GIFT OF 
 Author 
 

 
 

A PLEA FOR GREATER SIMPLICITY 
 IN THE LANGUAGE OF SCIENCE. 
 
 BY 
 T. A. RICKARD. 
 
 [Keprinted from SCIENCE, N. , Vol. XV., No. 369, 
 Pages 182-139, January $4., 1902.'] 
 
JL 
 
[Reprinted from SCIENCE, N. 8. t Vol. XV., No 369, r-i . .. -. 
 iges 132-139, January 24, 1902.] ) VN \ U rL 
 
 Pages 
 
 A PLEA FOR GREATER SIMPLICITY IN THE \^>9 \ 
 LANGUAGE OF SCIENCE* M As\ 
 
 SCIENTIFIC ideas are with difficulty solu- 
 ble in human speech. Man, in his contempla- 
 tion of the flux of phenomena at work all 
 about him, is embarrassed by the want of a 
 vehicle of thought adequate for expression, as 
 a child whose stammering accents do not per- 
 mit him to tell his mother the new ideas 
 which suddenly crowd upon him when he 
 meets with something alien to his experience. 
 
 Our knowledge of the mechanism of 
 nature has been undergoing a process of 
 growth, much of which has been sudden. 
 It is not surprising, therefore, that the in- 
 completely formed ideas of science should 
 become translated into clumsy language 
 and that inexact thinking should be evi- 
 denced by vagueness of expression. This 
 inexactness is often veiled by the liberal 
 use of sonorous Greek-Latin words. 
 
 The growth of knowledge has required 
 an increase in the medium of intellectual 
 exchange. New conceptions have called 
 for new terms. Sir Courtenay Boyle has 
 pointed out that the purity of a nation's 
 coinage is properly safeguarded, while the 
 verbal coinage of its national language is 
 subject to no control. Specially quali- 
 fied persons prepare the standards of gold 
 and silver. This insures the absolute 
 purity of the measures of commercial ex- 
 change and gives the English sovereign 
 and the American gold piece, for example, 
 an assured circulation along all the ave- 
 nues of commerce. It is not so with the 
 standards of speech. The nation debases 
 
 *A paper read before Section E of the Ameri- 
 can Association for the Advancement of Science, 
 August 28, 1901. 
 
 , * 
 
3 . : r ;i 3 
 V- ' , v ::':% 
 
 2 
 
 Its language with slang, with hybrid and 
 foreign words, the impure alloys and the 
 cheap imports of its verbal coinage, mere 
 tokens which should not be legal tender on 
 the intellectual exchanges. Prance has an 
 academy which in these matters has much 
 of the authority given to the Mint, whose as- 
 sayers test our metal coins; but in our coun- 
 try the mintage of words is wholly unre- 
 stricted, and, as a consequence, the English 
 language, circulating as it does to all the 
 four corners of the globe, has received an 
 admixture of fragments of speech taken 
 from various languages, just as the cur- 
 rency with which one is paid at the fron- 
 tier, where empires meet, includes the coin- 
 age of several governments, each of which 
 passes with an equally liberal carelessness. 
 Science ignores geographical lines and 
 bemoans the babel of tongues which hin- 
 ders the free interchange of ideas between 
 all the peoples of the earth. Nevertheless, 
 the international character of technical 
 literature is suggested by the fact that 
 three languages, French, German and 
 English, are practically recognized as the 
 standard mediums of intellectual exchange. 
 One of these affords the most lucid solvent 
 of thought, another is the speech, of the 
 most philosophical of European people and 
 the third goes with world-wide dominion, 
 so that each has a claim to become the 
 recognized language of science. The 
 brotherhood of thinking men will have 
 been fully recognized when all agree to 
 employ the same tongue in their inter- 
 course, but such a 'far-off divine event' 
 is not within the probabilities of the pres- 
 ent, consequently there remains only for 
 us to make the best of our own particular 
 language and to safeguard its purity, so 
 
3 
 
 that when it goes abroad the people of 
 other countries may at least be assured 
 that they are not dealing with the debased 
 currency of speech. 
 
 Barrie has remarked that in this age the 
 man of science appears to be the only one 
 who has anything to say and the only one 
 who does not know how to say it. It is 
 far otherwise in politics, an occupation 
 which numbers among its followers a great 
 many persons who have the ability for 
 speaking far beyond anything worth the 
 saying that they have to say. Nor is it so 
 in the arts, the high priests of which, ac- 
 cording to Huxley, have ' the power of ex- 
 pression so cultivated that their sensual 
 caterwauling may be almost mistaken for 
 the music of the spheres. ' In science there 
 is a language as of coded telegrams, by the 
 use of which a limited amount of informa- 
 tion is conveyed through the medium of 
 six-syllabled words. Even when not thus 
 overburdened with technical terms it is 
 too often the case that scientific concep- 
 tions are conveyed in a raw and unpala- 
 table form, mere indigestible chunks of 
 knowledge, as it were, which are apt to 
 provoke mental dyspepsia. Why, I ask, 
 should the standard English prose of the 
 day be a chastened art and the writing of 
 science, in a great scientific era, merely an 
 unkempt dressing of splendid ideas? The 
 luminous expositions of Huxley, the occa- 
 sional irradiating imagery of Tyndall, the 
 manly speech of Le Conte, and of a very 
 few others, all serve simply to emphasize 
 the fact that the literature of scientific re- 
 search as a whole is characterized by a flat 
 and ungainly style, which renders it dis- 
 tasteful to all but those who have a great 
 hunger for learning. 
 
To criticism of this sort the profession- 
 al scientist can reply that he addresses 
 himself not to the public at large, but to 
 those who are themselves engaged in simi- 
 lar research, and he may be prompted to 
 add to this the further statement that he 
 cannot pitch the tone of his teaching so as 
 to reach the unsensitive intelligence of per- 
 sons who lack a technical education. Fur- 
 thermore, he will claim that he cannot do 
 without the use of the terms to which 
 objection is made. However, in condemn- 
 ing the needless employment of bombastic 
 words of classical origin, in place of plain 
 English, I do not wish to be understood as 
 attacking all technical terms. They are 
 a necessary evil. Some of them are instru- 
 ments of precision invented to cover par- 
 ticular scientific ideas. Old words have 
 associations which sometimes unfit them to 
 express new conceptions and therefore 
 fresh words are coined. The complaint 
 lodged against the pompous, ungainly 
 wordiness of a large part of the scientific 
 writing of the day is that it is an obstacle 
 to the spread of knowledge. 
 
 Let us consider the subject as it is thus 
 presented. In the first place, does the ex- 
 cessive use of technical terms impede the 
 advancement of science? I think it does. 
 It kills the grace and purity of the litera- 
 ture by means of which the discoveries of 
 science are made known. Buskin, himself 
 a most accurate observer of nature, and 
 also a geologist, said that he was stopped 
 from pursuing his studies 'by the quite 
 frightful inaccuracy of the scientific peo- 
 ple's terms, which is the consequence of 
 their always trying to write mixed Latin 
 and English, so losing the grace of the one 
 and the sense of the other.' But grace of 
 
diction is not needed, it may well be said; 
 that is true, and it is also true that a clear, 
 forceful, unadorned mode of expression is 
 more difficult of attainment and more de- 
 sirable in the teaching of science than 
 either grace or fluency of diction. One 
 must not, as Huxley himself remarks, 
 { varnish the fair face of Truth with that 
 pestilent cosmetic, rhetoric,' and Huxley 
 most assuredly solved the problem of how 
 to avoid rhetorical cosmetics and yet con- 
 vey deep reasoning on the most complex of 
 subjects in addresses which are not only as 
 clear as a trout stream, but are also bright- 
 ened by warm touches of humanity, keen 
 wit and the glow of his own courageous 
 manhood. Nevertheless, though clearness 
 of expression be the first desired, yet grace 
 is not to be scorned. When you have a 
 teaching to convey, it is well to employ all 
 the aids which will enable you to get a 
 sympathetic hearing. Man lives not by 
 bread alone, much less by stones. He likes 
 his mental food garnished with a sauce. 
 Let the cooking be good, of course, but a 
 chef knows the value of a well-seasoned 
 adjunct to the best dish. 
 
 Our language is capable of a grace and 
 a finish greater than we give it credit. That 
 it is possible to write on geology, for in- 
 stance, in the most exquisite simple Eng- 
 lish has been proved by Ruskin, whose 
 'Deucalion' and 'Modern Painters' con- 
 tain many pages describing accurately 
 the details of the structure of rocks and 
 mountains, and dealing with their geologic- 
 al features in language which is marked 
 by the most sparing use of words which 
 have not an Anglo-Saxon origin. 
 
 The next aspect of the enquiry is 
 whether the language of science, apart 
 
from the view of mere grace of style in 
 literature, is not likely, in its present 
 everyday form, to delay the advance of 
 knowledge by its very obscurity. Leaving 
 the reader's feelings out of the argument, 
 for the present, it seems obvious that the 
 whole purpose of science, namely, the 
 search after truth, which is best advanced 
 by accuracy of observation and exactness 
 of statement, is hindered by a phraseology 
 which sometimes means very much but 
 oftener means very little, and, on the 
 whole, is most serviceable when required 
 as a cloak for ignorance. To distinguish 
 between what we know and what we think 
 we know, to comprehend accurately the 
 little that we do know, surely these are 
 the foundations of scientific progress. If 
 a man knows what a thing really is, he can 
 say so, describing it, for example, as being 
 black or white; if he does not know, he 
 masks his ignorance by stating in a few 
 Greek or Latin terms that it partakes of 
 the general quality of grayness. Writers 
 get into the habit of using words that they 
 do not clearly understand themselves and 
 which, as a consequence, must fail in con- 
 veying an exact meaning to their readers. 
 Many persons who possess only the smat- 
 tering of a subject are apt to splash all 
 over it with words of learned sound which 
 are more quickly acquired, of course, than 
 the reality of knowledge. Huxley said 
 that if a man does really know his subject 
 1 ' he will be able to speak of it in an easy 
 language and with the completeness of con- 
 viction, with which he talks of an ordinary 
 everyday matter. If he does not, he will 
 be afraid to wander beyond the limits of 
 the technical phraseology which he has 
 got up." If any scientific writer should 
 
complain that simplicity of speech is im- 
 practicable in dealing with essentially 
 technical subjects, I refer him to the course 
 of lectures delivered by Huxley to working- 
 men, lectures which conveyed original in- 
 vestigations of the greatest importance in 
 language which was as easily understood by 
 his audience as it was accurate when regard- 
 ed from a purely professional standpoint. 
 
 Science has been well denned as ' organ- 
 ized common sense ' ; let us then express its 
 findings in something better than a mere 
 jargon of speech and avoid that stupidity 
 which Samuel Johnson, himself an arch- 
 sinner in this respect, has fitly described 
 as 'the immense pomposity of sesquipeda- 
 lian verbiage.' George Meredith, a great 
 mint-master of words, has recorded his 
 objection to ' conversing in tokens not 
 standard coin. ' Indeed the clumsy latinity 
 of much of our scientific talk is an inherit- 
 ance from the schoolmen of the past; it is 
 the degraded currency of a period when 
 the vagaries of astrology and alchemy 
 found favor among intelligent men. 
 
 Vagueness of language produces loose- 
 ness of knowledge in the teacher as well as 
 the pupil. Huxley, in referring to the use 
 of such comprehensive terms as ' develop- 
 ment' and 'evolution,' remarked that 
 words like these were mere 'noise and 
 smoke/ the important thing being to have 
 a clear conception of the idea signified by 
 the name. Examples of this form of error 
 are easy to find. The word * dynamic ' has 
 a distinct meaning in physics, but it is 
 ordinarily employed in the loosest possible 
 manner in geological literature. Thus, the 
 origin of a perplexing ore deposit was re- 
 cently imputed to the effects produced by 
 the ' dynamic power ' which had shattered 
 
8 
 
 a certain mountain. ' Dynamic r is of 
 Greek derivation and means power ful, 
 therefore a 'powerful power ' had done 
 this thing ; but in physics the word is used 
 in the sense of active, as opposed to ' static r 
 or stationary, and it implies motion result- 
 ing from the application of force. In the 
 ease quoted, and in many similar instances, 
 the word ' agency ' or * activity ' would 
 serve to interpret the hazy idea of the 
 writer, and there is every reason to infer, 
 from the context, that he substituted the 
 term ' dynamic power 'merely as a frippery 
 of speech. It is much easier to talk grand- 
 iloquently about a ' dynamic power ' which 
 perpetrates unutterable things and recon- 
 structs creation in the twinkling of an eye 
 than it is to make a careful study of a 
 region, trace its structural lines and de- 
 cipher the relations of a complicated series 
 of faults. When this has been done and a 
 writer uses comprehensive words to sum- 
 marize activities which he has expressly 
 denned and described, then indeed he has 
 given a meaning to such words which war- 
 rants him in the use of them. 
 
 In this connection it is amusing to re- 
 member how Ruskin attacked Tyndall for 
 a similar indiscretion. The latter had re- 
 ferred to a certain theory which was in 
 debate, and had said that it, and the like 
 of it, was ' a dynamic power which operates 
 against intellectual stagnation/ Ruskin 
 commented thus : ' ' How a dynamic power 
 differs from an undynamic one, and, pre- 
 sumably, also, a potestatic dynamis from 
 an unpotestatic one and how much more 
 scientific it is to say, instead of that our 
 spoon stirs our porridge that it ' operates 
 against the stagnation of our porridge/ 
 Professor Tyndall trusts the reader to 
 recognize with admiration." 
 
Among geological names there is that 
 comfortable word ' metasomatosis ' and its 
 offspring of 'metasomatic interchange' 
 ' metasomatie action, ' ' metasomatie origin, ' 
 etc., etc. To a few who employ the term to 
 express a particular manner in which rocks 
 undergo change, it is a convenient word 
 for a definite idea, but for the greater 
 number of writers on geological subjects 
 it is a wordy cloud, a nebular phrase, 
 which politely covers the haziness of their 
 knowledge concerning a certain phenom- 
 enon. When you don't know what a thing 
 is, call it a ' phenomenon ' ! Instances of 
 mere vulgarity of scientific language are 
 too numerous to mention. ' Auriferous ' 
 and ' argentiferous ' are ugly words. They 
 are unnecessary ones also. The other day 
 a metallurgical specialist spoke of ' aurifer- 
 ous amalgamation' as though any process 
 in which mercury is used could be gold- 
 bearing unless it was part of the program 
 that somebody should add particles of gold 
 to the ore under treatment. A mining 
 engineer, of the kind known to the press 
 as an expert, described a famous lode as 
 traversing ' on the one hand a feldspathic 
 tuf aceous rock ' and ' on the other hand a 
 metamorphic matrix of a somewhat argillo- 
 arenaceous composition.' This is scientific 
 nonsense, the mere travesty of speech. To 
 those who care to dissect the terms used it 
 is easily seen that the writer of them could 
 make nothing out of the rocks he had ex- 
 amined, save the fact that they were de- 
 composed and that the rock which he de- 
 scribed last might have been almost any- 
 thing, for all he said of it; for his de- 
 scription, when translated, means literally 
 a changed matter of a somewhat clayey- 
 sandy composition, which, in Anglo-Saxon, 
 
10 
 
 is m-u-d! The 'somewhat* is the one use- 
 ful word in the sentence. Such language 
 may be described in the terms of miner- 
 alogy as metamorphosed English pseudo- 
 morphic after blatherskite. Some years 
 ago, when I was at a small mine near 
 Georgetown, in Colorado, a professor 
 visited the underground workings and was 
 taken through them. He immediately be- 
 gan to make a display of verbal fireworks 
 which bewildered the foreman and the 
 other miners whom he met in the mine, all 
 save one, a little Cornishman, who, bring- 
 ing him a bit of the clay which accom- 
 panied one of the walls of the lode, said to 
 him, 'What do 'ee call un, you?' The 
 professor replied, ' It is the argillaceous 
 remnant of an antediluvian world.' Quick 
 as a flash came the comment, * That's just 
 what I told me pardner.' He was not de- 
 ceived by the vapor of words. 
 
 Next consider the position of the reader. 
 It is scarcely necessary at this date to plead 
 for the cause of technical education and 
 the generous bestowal of the very best that 
 there is of scientific knowledge. The great 
 philosophers of that New Reformation 
 which marked the era of the publication of 
 * The Origin of Species ' have given most 
 freely to all men of their wealth of learn- 
 ing and research. When these have given 
 so much we might well be less niggardly 
 with our small change and cease the prac- 
 tice of distributing, not good wholesome 
 intellectual bread, but the mere stones of 
 knowledge, the hard fossils of what were 
 once stimulating thoughts. In the ancient 
 world the Eleusinian mysteries were with- 
 held from the crowd and knowledge was 
 the possession of a few. Do the latter day 
 priests of science desire to imitate the at- 
 
11 
 
 tendants of the old Greek temples and con- 
 fine their secrets to a few of the elect by 
 the use of a formalism which is the mere 
 abracadabra of speech? Among certain 
 scientific men there is a feeling that scien- 
 tists should address themselves only to 
 fellow scientists, and that to become an 
 expositor to the unlearned is to lose caste 
 among the learned. It is the survival of 
 the narrow spirit of the dark ages, before 
 modern science was born. There are not 
 many, however, who dare confess to such 
 a creed, although their actions may occa- 
 sionally endorse it. On the whole, modern 
 science is nothing if not catholic in its 
 generosity. ' To promote the increase of 
 natural knowledge and to forward the ap- 
 plication of scientific methods of investiga- 
 tion to all the problems of life ' was the 
 avowed purpose of the greatest of the phi- 
 losophers of the Victorian era. 
 
 There are those who are full of a similar 
 good will, but they fail in giving effect to it 
 because they are unable to use language 
 which can be widely understood. In its 
 very infancy geology was nearly choked 
 with big words, for Lyell, the father of 
 modern geology, said, seventy years ago, 
 that the study of it was ' very easy, when 
 put into plainer language than scientific 
 writers choose often unnecessarily to em- 
 ploy/ At this day even the publications 
 of the Geological Surveys of the United 
 States and the Australian colonies, for ex- 
 ample, are occasionally restricted in use- 
 fulness by erring in this respect, and as I 
 yield to none in my appreciation of the 
 splendid service done to geology and to 
 mining by these surveys, I trust my criti- 
 cism will be accepted in the thoroughly 
 friendly spirit with which it is offered. It 
 
12 
 
 seems to me that one might almost say 
 that certain of these extremely valuable 
 publications are " ' badly ' prepared be- 
 cause they seem to overlook the fact that 
 they are, of course, intended to aid the 
 mining community in the first place and 
 the public, whether lay or scientific, only 
 secondarily. From a wide experience 
 among those engaged in mining I can 
 testify that a large part of the literature 
 thus prepared is useless to them and that 
 no one regrets it more deeply than they, 
 because there is a marked tendency among 
 this class of workers to appreciate the 
 assistance which science can give. Take, 
 for example, a sentence like the following, 
 extracted from one of the recent reports of 
 the U. S. Geological Survey. "The ore 
 forms a series of imbricating lenses, or a 
 stringer lead, in the slates, the quartz con- 
 forming as a rule to the carunculated 
 schistose structures, though occasionally 
 breaking across laminae, and sometimes the 
 slate is so broken as to form a reticulated 
 deposit/' This was written by one of our 
 foremost geologists and, when translated, 
 the sentence is found to convey a useful 
 fact, but is it likely to be clear to anyone 
 but a traveling dictionary? A thoroughly 
 literary man might know the exact mean- 
 ing of the two or three very unusual 
 words which are employed in this state- 
 ment, but the question is, will it be of any 
 use whatever even to a fairly educated 
 miner, or be understood by those who pay 
 for the preparation of such literature, 
 namely, the taxpayers? An example of 
 another kind is afforded by a Tasmani^n 
 geologist who recently described certain 
 ores as due to ' the effects of a reduction in 
 temperature of the hitherto liquefied hy- 
 
13 
 
 droplutonic solutions, and their conse- 
 quent regular precipitation.' These solu- 
 tions, it is further stated, presumably 'for 
 the guidance of those who wield the pick, 
 ' ascended in the form of metallic super- 
 heated vapors which combined eventually 
 with ebullient steam to form other aque- 
 ous solutions, causing geyser-like discharges 
 at the surface, aided by subterranean and 
 irrepressible pressure/ At the same time 
 certain * dynamical forces ' were very busy 
 indeed and 'eventuated in the opening of 
 fissures' of which one can only regret 
 that they did not swallow up the author 
 as Nathan and Abiram were once engulfed 
 in the sight of all Israel. 
 
 It will be well to contrast these two ex- 
 amples of exuberant verbosity because the 
 first befogs the statement of a scientific 
 observation of value, made by an able man, 
 while the second cloaks the ignorance of a 
 charlatan, who masquerades his nonsense 
 in the trappings of wisdom. Here you 
 have an illustration of the harmfulness of 
 this kind of language, which obscures 
 truth and falseness alike, to the degrada- 
 tion of science and the total confusion of 
 those of the unlearned who are searching 
 after information. 
 
 Let the writer on scientific matters learn 
 the derivation of the words he uses and 
 then translate them literally into English 
 before he uses them, and thereby avoid the 
 unconscious talking of nonsense. If he 
 knows not the exact meaning of the terms 
 which offer themselves to his pen, let him 
 avoid them and trust to the honest aid of 
 his own language. ' Great part of the sup- 
 posed scientific knowledge of the day is 
 simply bad English, and vanishes the 
 moment you translate it,' says Ruskin. 
 
14 
 
 The examples already given illustrate this. 
 ' Every Englishman has, in his native 
 tongue, an almost perfect instrument of 
 literary expression,' so says Huxley, and 
 he illustrated his own saying. Huxley and 
 Ruskin were wide apart in many things 
 and yet they agreed in this. Ruskin 
 proved abundantly that the language of 
 Shakespeare and the Bible can be used as 
 a weapon of expression keen as a Damascus 
 saber when it is freed from the rust of 
 classic importations, which make it clumsy 
 as a crowbar. 
 
 There is yet another reason against the 
 excessive use of Greek-English words, in 
 particular. Greece is not a remnant of ex- 
 tinct geography, but an existing land with 
 a very active people and a living language. 
 The terms which paleontology has bor- 
 rowed from the Greek may be returned by 
 the Greeks to us. And, as Ruskin points 
 out, ' ' What you, in compliment to Greece 
 call a ' Dinotherium, ' Greece, in compli- 
 ment to you, must call a ' Nasty-beastium, ' 
 and you know the interchange of compli- 
 ments can't last long." 
 
 In all seriousness, however, is it too 
 much to ask that such technical terms as 
 are considered essential shall not be used 
 carelessly, and that in publications in- 
 tended for an untechnical public, as are 
 most government reports, an effort be 
 made to avoid them and, where unavoid- 
 able, those which are least likely to be un- 
 derstood shall be translated in footnotes. 
 Even as regards the transactions of scien- 
 tific societies, I believe that those of us 
 who are active members have little to lose 
 and much to gain by confining the use 
 of our clumsy terminology to cover ideas 
 which we cannot otherwise express. By 
 
15 
 
 doing so we shall contribute, I earnestly 
 believe, to that advancement of science 
 which we all have at heart. 
 
 The words which, at first, are the ex- 
 clusive privilege of the specialist, gradually 
 extend into wider use, following in the 
 wake of that diffusion of scientific knowl- 
 edge which is one of the objects of this 
 Association. We believe that to get along- 
 side facts, to apply the best knowledge 
 available, to seek truth for its own sake, is 
 as essential to the well-being of the in- 
 dividual life as it is to the success of a 
 machine shop, and as beneficial to the com- 
 munity as it is to a smelting works. 
 
 In furtherance of this principle we must 
 remember that language in relation to 
 ideas is a solvent, the purity and clearness 
 of which affect that which it bears in solu- 
 tion. Whewell, in ' The Philosophy of the 
 Inductive Sciences, 'has expressed this view 
 of the matter with noble eloquence. ' Lan- 
 guage, ' he said, l is often called an instru- 
 ment of thought, but it is also the nutri- 
 ment of thought; or rather, it is the 
 atmosphere in which thought lives; a 
 medium essential to the activity of our 
 speculative powers, although invisible and 
 imperceptible in its operation, and an ele- 
 ment modifying, by its qualities and 
 changes, the growth and complexion of the 
 faculties which it feeds.' 
 
 In considering the subject from this 
 standpoint, there is borne in upon the 
 mind a suggestion which carries our 
 thought far beyond the confines of the mat- 
 ter under discussion. Such power of 
 speech as man possesses is a faculty which 
 appears to divide him from all other liv- 
 ing things, while at the same time the im- 
 perfection of it weighs him down con- 
 
16 
 
 tinually with the sense of an essential 
 frailty. To be able to express oneself per- 
 fectly would be divine, to be unable to 
 make oneself understood is human. In 
 'Man's Place in Nature/ Huxley points 
 out that the endowment of intelligible 
 speech separates man from the brutes 
 which are most like him, namely, the an- 
 thropoid apes, whom he otherwise resem- 
 bles closely in substance and in structure. 
 This endowment enables him to transmit 
 the experience which in other animals is 
 lost with each individual life; it has en- 
 abled him to organize his knowledge and 
 to hand it down to his descendants, first by 
 word of mouth and then by written words. 
 If the experience thus recorded were prop- 
 erly utilized, instead of being largely disre- 
 garded, then man's advancement in knowl- 
 edge and conduct would enable him to 
 emphasize, much more than it is permitted 
 him at present, his superiority over the 
 dumb brutes. Considered from this stand- 
 point language is a factor in the evolution 
 of the race and an instrument which works 
 for ethical progress. It is a gift most truly 
 divine which should be cherished as the 
 ladder which has permitted of an ascent 
 from the most humble beginnings and leads 
 to the heights of a loftier destiny, when 
 man, ceasing to stammer forth in accents 
 which are but the halting expression of 
 swift thought, shall photograph his mind 
 in the fulness of speech, and, neither with- 
 holding what he wants to say nor saying 
 what he wants to withhold, shall be linked 
 to his fellow by the completeness of a per- 
 fect communion of ideas. 
 DENVEB. T. A. RlCKAED. 
 
" The Minerals which accompany Gold, and their bearing 
 upon the Richness of Ore Deposits." 
 
 By T. A. RICKARD, M.Inst. M.M. 
 
 IN the general advance of knowledge anatomy has distanced 
 medicine. The surgeon works with confident skill while the 
 diagnosis of the physician is yet a faltering guess. It is thus in 
 our own profession. The structure of the rocky envelope of the 
 earth has been in many localities so carefully deciphered that the 
 mining engineer can unravel the geology of an ore deposit with a 
 saccess to which the mines of Leadville, Bendigo and Gympie 
 bear ungrudging testimony. When, however, he endeavours to 
 ascertain the causes which have determined the presence of gold 
 at one spot and its absence at another he hesitates, and, saturated 
 with the brutal experience of widely separated regions, he con- 
 fesses that it is a phenomenon yet to be explained. 
 
 The working of gold mines in different countries has yielded an 
 accumulation of scattered evidence which needs only scant examina- 
 tion to emphasise how incomplete and contradictory it is. The 
 absence of accurate knowledge on this subject has encouraged the 
 growth of attractive fallacies, in the combating of which the whole 
 matter often comes up for informal discussion wherever mining 
 men congregate. During recent journeyings over the goldfields 
 of West Australia, I found that many an old fallacy had sprung 
 again into vigorous life amid the congenial atmosphere of a com- 
 munity over which the windy breath of a boom had but lately 
 passed. 
 
 It may seem a thankless task to oppose those plausible theories, 
 which become rampant only when facts are scarce, yet I am 
 convinced that in the search after truth the first step must be to 
 
 B 
 
sift the little that \ve really do know from the much that we think 
 we know ; the first is science, the second is popular knowledge. 
 The old industry of mining was formerly guided by the venerable 
 rule of thumb, and would forever have remained but a blind sort 
 of groping in the dark had it not obtained the willing aid of the 
 younger science of geology. 
 
 The immediate problem to which my most recent experience 
 has called attention may be summarised thus : In examining a 
 lode only incompletely developed and in a new country, what is 
 the evidence on which a correct estimate of the prospective value 
 of the mine may best be based ? The two most common answers 
 would be a plain denial of any man's ability to see further into 
 the ground than the point of his pick, and against this obvious 
 surrender would come the reply that the best indication would be 
 found in the presence of particular minerals in association with 
 the gold. 
 
 It is this question of indicative minerals which I purpose dis- 
 cussing. The experience of certain mining districts has gone to 
 prove that gold is notably accompanied by particular minerals, 
 and this to such an extent that they are considered to assure the 
 richness of an ore in which the gold itself cannot visibly be 
 discerned. These " indicative minerals," as they may be termed, 
 are not the same in every locality. A few examples, such as 
 have come within my own experience, may be quoted. Every 
 mining engineer can add to the list. 
 
 In Boulder county, Colorado, roscoelite (a vanadium mica) is 
 closely associated with the tellurides of gold (calaverite and 
 sylvanite). This fact is rendered of additional interest because the 
 same rare mineral has been recognised by me in the telluride ores 
 of Kalgoorlie, in West Australia.* At San Andreas, in California, 
 uranium ochre (the yellow oxide of uranium) is found to distin- 
 guish the pockets of specimen gold ore to such an extent as to 
 serve as a guide in prospecting. In several parts of Arizona, in 
 Yuma, Yavapai and Final counties, especially the last, vanadinite 
 and descloizite (both vanadates of lead) characterise ores rich in 
 gold and silver. Wulfeiiite (the molybdate of lead) often accom- 
 panies the vanadium minerals, and has been noticed in the ores of 
 two celebrated lodes, the Comstock in Nevada and the Vulture 
 in Arizona. The association of gold with these lead ores is 
 notable, because the particular minerals mentioned are all of 
 great beauty and delicacy. The same may be said of crocoite 
 
 * Eoscoelite also occurs generously in the veins of the district (El Dorado) 
 where gold was first discovered in California. 
 
(the chromate of lead), which characterises several gold veins in 
 the North Coolgardie goldfield, especially at Menzies.* The 
 more common sulphide, galena, is also an accessory mineral in the 
 richest mines at Menzies, and accompanies coarse native gold. At 
 Niagara, Pinyalline, and Wagiemoola, three widely separated 
 localities in West Australia, I found gold closely associated with 
 tourmaline in the form of acicular crystals in contact with coarse 
 pold, and also in a condition of minute diffusion forming dark 
 blotches in the white quartz. The gold ores of the Mysore in 
 India carry tourmaline. 
 
 Instances might be multiplied, but it would be to no purpose. 
 Those already cited will serve as a sufficient text for the discus- 
 sion of the subject. 
 
 Such occurrences as these would seem at first sight to afford 
 a much needed aid to the explorer. It is unfortunately easy 
 to prove that as evidence they, and any number more of them, 
 are of very uncertain value in a new mining territory, because 
 they are contradicted by similar testimony of a negative kind, 
 which compels us to regard them as mere coincidences. Take the 
 case of zinc blende. One locality was quoted where this mineral 
 is a sure sign of a generous amount of gold and silver in the ore. 
 The Morgan Mine, in Wales, affords, I understand, corroborative 
 testimony. At the East Murchison Mine, in West Australia, this 
 mineral has been found to be an almost unerring guide in separat- 
 ing rich from poor ore. But in Arizona it is a common experience 
 that the impoverishment of lodes in depth, when it does occur, is 
 concomitant with an increasing percentage of zinc. Other regions 
 echo this unpleasant fact. Broken Hill knows it. Similarly, there 
 is the beautiful mineral fluorite or fluorspar. The association of 
 fluorite with the tellurides of gold was early recognised in both 
 the Boulder and Cripple Creek districts of Colorado, and the 
 purple tint imparted by this mineral was speedily bailed as a 
 distinction peculiar to rich veins. Later experience, notably in 
 Park County, has proved that poor ores are favoured with fluorite 
 no less than the bonanzas. 1 have mentioned a locality where 
 rhodochrosite is esteemed a favourable mineral. But while it is 
 thus characteristic of rich ore at Rico, in Colorado it is a negligi- 
 ble factor in certain lodes at Butte City, Montana. Again, 
 consider calcite. When it is seen amid the gold bearing quartz of 
 California it is recognised with regret, because it so often means a 
 falling off in values, while at Kalgoorlie the same mineral charac- 
 
 * Dana mentions that crocoite is associated with gold in the quartz of 
 Kiznhi Tagilsk in the Urals. 
 
 B 2 
 
terises ores rich in calaverite (the telluride of gold), and at Rhuda 
 in Transylvania, a very valuable gold vein has been worked whose 
 matrix was essentially calcite. 
 
 We are all familiar with mines in which iror pyrites is so 
 intimately associated with the gold that a lessening of the one 
 means a diminution in the other, but there are also cases where 
 an excessive percentage of pyrites coincides with impoverishment. 
 Moreover, there are lodes in which the coarse cubes of pyrites are 
 less favourable to the presence of gold than the finely crystalline 
 variety, but there are also those in which the reverse is true. 
 Much in the same way, there used to be an idea that coarse cubical 
 galena was less silver-bearing than the fine grained kind, but this 
 as a generalisation has long since been exploded. Thus, therefore, 
 it requires but little sifting of this sort of evidence to emphasise 
 its contradictory character. 
 
 The rich lodes of the same district frequently differ widely in 
 their mineralisation.* Poor veins often carry the ores considered 
 characteristic of the rich ones. The neglect of the former causes 
 this fact to be overlooked. "When the field of comparison is 
 enlarged from mines to whole districts the divergence of evidence 
 becomes tenfold emphasised. 
 
 In matters like these the experience of each mining engineer 
 is a personal equation by which every theory must be eventually 
 tested. Out of the whole sad wreck of glittering generalisations 
 on this particular subject, only one or two have survived my own 
 particular trial of them, and even they, I fear, await the destruc- 
 tive testimony which may at any moment be found in the develop- 
 ment of new mining regions. When gold occurs in pyrrhotite 
 ores it has been as yet invariably proved to be in immediate asso- 
 ciation with a small, often overlooked, percentage of copper 
 pyrites. The testimony of Montana, Colorado, and British 
 Columbia is at one in this deduction. Again, while many veins 
 carrying coarse gold encased in white quartz persist to great 
 depths, and in this respect Bendigo does especially set at naught 
 the dictum of American experience, nevertheless I have not known 
 gold quartz to be persistent when wholly barren of the sulphides 
 of the baser metals, while, on the other hand, I do remember in- 
 numerable examples of ore quite destitute of pyrites, galena, and 
 blende which proved particularly short lived. I might venture 
 
 * This word is not of vulgar coinage. It comes through the French, who 
 use it as we do, to express the fact that a rock carries minerals of economic 
 value, that is, ore. " Mineralise " is the equivalent of " mineralised," and is 
 related rather to the word " mineral" (ore) than to " mineral." 
 
one other. There is no better indirect evidence of the size of a 
 body of gold ore than uniformity in the distribution of the gold. 
 A patchy occurrence is less likely than homogeneity to indicate 
 continuity or size; samples which vary between narrow limits are 
 more encouraging than those which swing between wide extremes 
 of richness and poverty. It is with a desire to avoid a merely 
 destructive attitude that I have dared to offer these three obser- 
 vations. 
 
 While therefore the evidence in support of the value of the 
 supposed indicative minerals is, as we have seen, of a very contra- 
 dictory nature, it also has another feature which must not be 
 
 overlooked. At its best, the aid of these minerals would be delu- 
 
 
 sive, because, even if it proved the invariable association of gold 
 with particular minerals, it could not predicate the actual amount 
 of that gold. That a lode should carry gold is quite insufficient 
 to the mining engineer, whose operations for its profitable extrac- 
 tion require that it should be there in paying quantity. This is 
 the difference between science and business. The union of the 
 two creates an industry. One might discuss in a learned and 
 entertaining manner, as Stelzner has done, the suggestiveness of 
 the association of gold with such a compound as the silicate of 
 boron and aluminium (tourmaline), because it indicates a deep- 
 seated origin. The presence in notable quantity of the fluoride of 
 calcium (fluorspar) might prompt speculations of a vapourous and 
 corroding kind. But the proof of gold having either a profound 
 or a gaseous origin, were it attained by the geologist or chemist, 
 would not permit the mining engineer to infer that the gold per- 
 sists in paying quantity to any particular depth. An ore which 
 carries 2 dwt. per ton in a region where the conditions are such 
 as to require the equivalent of 15 dwt. to be expended in the 
 extraction and reduction of a ton, is to all practical intent as value- 
 less as one which is wholly barren. 
 
 The question of indicative minerals bears many points of resem- 
 blance to that of the plants which have been observed to distin- 
 guish the soil enriched by particular ores. The Viola Intea was 
 supposed to be peculiar to the soil covering the zinc deposits of 
 Westphalia, and was subsequently recognised growing on the out- 
 crop of the zinc ores of the Horn Silver Mine in Utah. It became 
 known as the " zinc plant." Similarly there is a so-called " lead 
 plant," the Amorpha canescens, which characterises the lead deposits 
 of Michigan, Wisconsin, and Illinois. These plants are local 
 varieties rather than a distinct species, their colour being affected 
 by their absorption of the particular metallic ingredient in the 
 
soil.* Their occurrence has long ceased to have anything more 
 than academic interest. 
 
 If then we cannot accept the belief that certain minerals are 
 indicative of the plentiful occurrence of gold, what shall be said 
 for the idea that they give an assurance of persistence in depth ? 
 Every one has read serious statements to the effect that this or 
 that mine was of undoubted value because its ores contained par- 
 ticular minerals, the presence of which promised that the vein 
 would increase in richness in depth. In young mining regions 
 such ideas find a fertile soil. In West Australia the finding of 
 tellurides in an ore is now generally considered to permit of the 
 inference that the lode will go down to a great depth. The early 
 discoveries of extraordinary pockets of native gold in veins of 
 white quartz, such as made the Londonderry famous, proved 
 sporadic and bunchy to a distressing degree. When, therefore, 
 the telluride ores of Kalgoorlie became recognised, and were found 
 to occur in bodies of magnificent size and very satisfactory per- 
 sistence, the conclusion was jumped at that if tellurides were only 
 present in an ore, continuity in depth became thereby guaranteed. 
 Post hoc, ergo propter hoc. 
 
 In these matters a very small portion of ascertained truth is 
 swamped amid a mass of supposition quite unworthy of the name 
 of theory. A theory embodies an underlying principle of universal 
 application. The idea which to-day dominates the mining of Wes- 
 tralia is a vain imagining, delusive as a promoter's dream. 
 
 Those who are acquainted with the history of the mining of 
 tellurides need not be told how ill founded is the statement that 
 these particular minerals characterise lodes of peculiar perma- 
 nence. The combinations of tellurium with gold and silver have 
 proved of notable commercial importance in three mining regions, 
 namely, Transylvania, Colorado, and West Australia. There are 
 other districts where the mining of them is an incident in the 
 working of ordinary gold ores. Such is the case in certain locali- 
 ties in California, South Dakota, and the North Island of New 
 Zealand. In none of these, however, have they been indicative 
 of any special persistence in the richness of the veins, and their 
 occurrence has been merely an added obstacle to the successful 
 extraction of the gold. 
 
 It was in 1802 that Klaproth discovered the presence of a new 
 element, tellurium, in the ores of Zalathna, and so led to the 
 recognition of a large number of the compounds of that metal 
 
 * See " Indicative Plants," by E. W. Kajrnond, Trans. Amer. last, of M.E., 
 vol. xv, p. 644. 
 
with gold and silver. Zalathua, Nagyag, and Verospatak were 
 gold mining centres when Transylvania was the Roman province 
 of Dacia and was ruled by Trajan. The very complex ores of these 
 districts have been a puzzle to the metallurgists of many genera- 
 tions. The veins penetrate young volcanic rocks (andesites) and 
 Tertiary limestones, sandstones, and conglomerates. This very 
 ancient mining country exhibits to-day a very forceful example of 
 impoverishment in depth, while the refractory character of the 
 ores has tried the resources of the smelting establishments of 
 Schemnitz, Zalathna, and Freiberg. 
 
 In Colorado the tellurides were recognised as early as 1874 in 
 Boulder county, more especially at the mines of Magnolia, Salina, 
 and Sunshine. An experience of nearly twenty-five years has proved 
 to the miners of that county that these ores occur there in compara- 
 tively small bodies of remarkable richness but of very irregular 
 and uncertain behaviour. In two other districts of the same State, 
 namely, in Hinsdale county and amid the La Plata mountains, 
 valuable mines, carrying ores rich in the tellurides of gold and 
 silver, have been worked during the past ten years, but their 
 record corroborates that of Boulder. There remains the more 
 important goldfield of Cripple Creek, where veins penetrating a 
 remarkable complex of volcanic rocks have proved so persistently 
 rich to a depth now approaching one thousand feet, that they have 
 obliterated the reputation which this class of ore won in the three 
 older parts of the same State. 
 
 In West Australia tellurides are being mined in three localities 
 Redhill, Bardoc, Kalgoorlie and the wonderful development of 
 the last has given a new impulse to the whole industry of the colony. 
 
 Thus, one hears much of Cripple Creek, and, lately, of Kal- 
 goorlie. In both districts very rioh lodes, characterised by telluride 
 ores, have been opened up, with results so eloquent as to silence 
 the story of the more numerous localities where these particular 
 minerals have been only a metallurgical obstacle associated with 
 ore bodies of no satisfactory continuity. As a consequence, 
 investors are prepared to swallow the rhetorical confectionery of 
 an irresponsible press, and to believe that a new era has dawned 
 for any neglected region in which these tellurides are now for the 
 first time recognised. Believe me, the compounds of tellurium 
 are far more widely dispersed in gold ores than is generally sup- 
 posed. I have detected them in several mines when a low extrac- 
 tion in the stamp mill suggested an unusual difficulty in the ore, 
 and it is certain that during the next few years the greater 
 familiarity with these minerals will lead to their recognition in 
 
8 
 
 so many unsuspected localities, that they will cease to be a 
 mineral ogical curiosity.* 
 
 The idea, now very prevalent, that at Kalgoorlie especially the 
 presence of tellurides guarantees persistent richness is contradicted 
 by several facts, the most notorious of which should be the fact 
 that the very mine in which they were first recognised (by Mr. J. 
 C. Moulden, in May, 1896), and subsequently acclaimed by the 
 local press as heralding sure prosperity, has proved unprofitable ; 
 indeed, the particular ore-body in which the first telluride was 
 seen has been demonstrated by later development to be an isolated 
 patch leading to nothing of any moment. Moreover, the lodes at 
 Kalgoorlie vary in the amount of tellurides which they carry 
 without any proportionate difference in their richness. The 
 gold occurs not only in chemical combination with tellurium, but 
 also in its ordinary native condition. Further, tellurides occur 
 which do not contain gold. The so-called " black tellurium" of 
 certain mines is the rare telluride of mercury, called " coloradoite," 
 from the locality of its first discovery. Native tellurium also 
 exists. Again, some of the veins even below the zone of oxidation 
 are so free from tellurium as not to differ from ordinary gold- 
 bearing reefs. Yet there is no reason to suppose that these are 
 less rich or less persistent than those which are characterised by 
 a notable percentage of tellurides. 
 
 It is not too much to say, therefore, that the observations 
 gathered from the working of telluride ores in various parts of 
 the world refute the idea that their occurrence has any particular 
 bearing on the question of persistence in depth ; while, on the 
 other hand, experience has frequently demonstrated that their 
 presence is an important and objectionable factor from a metal- 
 lurgical standpoint, because it increases the cost of gold extraction. 
 
 Thus we are brought to face the general question of the enrich- 
 ment of ores in depth. It is, however, outside the scope of this 
 contribution. As a far-reaching fallacy, persisting in spite of the 
 accumulated experience of many mining regions, it possesses a 
 pestilent vitality, which must at times astonish those who from 
 the actual direction of mining operations have seen so much 
 evidence to the contrary. I am referring now to gold mines only, 
 
 * The sulphide ore of Mount Morgan, Queensland, carries tellurides. The 
 fict was recently determined by Mr. E. S. Simpson, G-overnment Assayer for 
 West Australia. How much of the early trouble in the treatment of the 
 oxidised ores is explained by this discovery ? It also recalls to me the 
 resemblance between the dull brown gold of some of the Mount Morgan ore 
 and that of the first discoveries at Cripple Creek in 1892. 
 
because the facts relating to baser metals, which by oxidation 
 become soluble, differ in detail. Gold and tin are in this respect 
 unlike copper and silver. While, therefore, I do not wish on this 
 occasion to reopen the whole subject, I cannot forbear referring 
 to the question as it has come up for discussion in West Australia, 
 where I have lately been. 
 
 In that country the assertion is made with tiresome iteration 
 that veins become richer below the water level, because in the 
 oxidised zone the ore has been impoverished by the leaching out 
 of the gold. It is also held by many who pose as having authority 
 and not as the scribes, that if the outcrop give evidence of notable 
 mineralisation it is reasonable to expect almost barren quartz to 
 become valuable when the sulphides are reached in the ordinary 
 course of deeper mining. If these pleasant doctrines are ques- 
 tioned, you are bidden to go to Kalgoorlie, where, so they say, 
 you will be forced by the evidence there obtainable to admit the 
 fact that lodes which now attract the attention of the financial 
 world, were too poor to meet expenses until the mine workings 
 penetrated into the unoxidized ore. Indeed, at Kalgoorlie especi- 
 ally this idea has a strong foothold, especially among stock- 
 jobbers. 
 
 The matter seemed to me to be one of great interest. If the 
 facts really did indicate a general enrichment of the veins as they 
 approached the drainage level of the district, which is also the 
 water level of the mines, then Kalgoorlie offered a striking excep- 
 tion to the experience of other goldfields. If, moreover, a satis- 
 factory theory were forthcoming to account for these unusual 
 facts, then the uncertain chemistry of ore occurrence would 
 receive invaluable aid. But the prettily coloured bubble was 
 dissipated as soon as an earnest investigation was commenced. 
 The history of the development of the lodes, and a few quiet con- 
 versations with the able men who have come from elsewhere to 
 direct the big mines, were sufficient to stamp this as another 
 resurrection of a fallacy that was old before the Phoenicians came 
 to Cornwall. 
 
 To say that mines get richer in depth is, in such a region as 
 West Australia, a cruel cynicism. If anyone is inclined to believe 
 it, let him wander over the desert, and count the idle stamp mills 
 which lie rusting in the sweltering sun, and the long succession of 
 abandoned shafts which now serve only to water the passing 
 camel train. By mere repetition of an untruth you may effect 
 persuasion, but you do not alter the falsity of it. 
 
 If you omit the manifest failures and turn to the production of 
 
 B 3 
 
10 
 
 the more successful mines in the Menzies, Murchison, Cool- 
 gardie, and Norseman goldfields, you will still find that it is a 
 work of supererogation to attempt a serions discussion of the 
 statement that the veins have improved in depth. Incomplete as 
 the Government statistics are, and vitiated by a total lack of 
 system in the determination of the actual tonnage treated at the 
 mills, yet they, too, tender an emphatic denial.* 
 
 The alleged facts are further explained by a general hypothesis 
 that the gold in the oxidised ore has been leached out so that it is 
 beneath its normal richness, which will be found nnimpaired 
 below the water level. This is stated to be evidenced by the 
 removal of the iron pyrites, the casts of the crystals of which now 
 appear as cavities in the quartz. In some of these gold is found, 
 but in others it is absent, proving, so it is said, that the gold has 
 been removed from the cavities which are now empty. The occur- 
 rence of films of fine gold, called " paint gold," on the faces of 
 fractures is instanced as an illustration of secondary reactions. 
 Finally, the alkaline composition of the waters in the mines is 
 quoted in proof of their solvent power. 
 
 Although the chemistry of the oxidised zone is far from being 
 thoroughly understood, yet in its incompleteness it is sufficient to 
 disprove these arguments. When iron pyrites is decomposed the 
 sulphide becomes a sulphate, and this in turn, by further oxida- 
 tion in the presence of water, is resolved into sulphuric acid and 
 the hydrated oxide of iron. The native sulphur frequently seen 
 in the cavities left by the removal of the cubes of pyrites is not a 
 direct product of decomposition, but is traceable to later secondary 
 reactions in which the organic matter of the surface has served as 
 a reducing agent. The gold intimately mixed with the pyrites, 
 and probably originally deposited with it, remains, because the 
 noble metal is insoluble to the waters which dissolved the iron. 
 
 The occurrence of gold in pyrites is now less of a mystery 
 than it used to be. Microscopic examination has disclosed the 
 existence of the gold in the planes of the pyrites, and the leaching 
 of the gold by cyanide solutions without any apparent deformation 
 of the pyrites is no less suggestive. It is indeed true that in some 
 of the casts, left by the removal of the sulphides gold does not 
 occur, but this is frequently due to the fact that it is very diffi- 
 cult to break a piece of cellular quartz without shaking the gold 
 out of the cavities in which it lies loosely. Hence their emptiness 
 
 * Of course the grand totals are misleading, since they include the produc- 
 tion of new mines, and do not indicate the shutting down of unprofitable ones. 
 The yields of individual mines must be consulted. 
 
11 
 
 may mean nothing. At other times this may indeed be due to the 
 real absence of the gold, and against this observation we then 
 balance another, namely, that the pyrites as we find it unaltered 
 below the water level also varies in its gold contents, so that in 
 the same vein it is sometimes barren and sometimes rich, account- 
 ing in this way for the uncertain presence of free gold in the 
 oxidised zone. The "paint gold," frequently noticed in the 
 gossan, appears to be the result of secondary and comparatively 
 recent reactions. It is, however, only a proof of precipitation, 
 and therefore presupposes a previous leaching, but not necessarily 
 in the vadose region. It evidences local enrichment rather than 
 impoverishment. 
 
 Of the solvent power of surface waters upon the gold there is 
 only supposition, and this supposition must first overcome the 
 fact of the occurrence of such organic matter in the ground 
 approaching the surface as would reduce any known salts of gold 
 should they be in solution. In the Sugarloaf Mine, near Kunanal- 
 ling, I saw the roots of trees at 74 ft., and in the Great Boulder 
 Main Reef Mine, at Kalgoorlie, I saw some which had penetrated 
 the rock to 85 ft. below the surface. In the former case the 
 oxidation of the enclosing rock ceases at 130 ft. and in the latter 
 at 175 ft. The region is an unusually dry one, which has under- 
 gone erosion with extreme slowness ; and this is doubtless the 
 reason why roots in search of moisture should penetrate so deeply. 
 
 The waters of the mines are all brackish ; they are many times 
 more salt than the sea. Analyses made at the Great Boulder 
 Proprietary Mine show an average in solids of 8'9 per cent., and 
 of this 6*2 was chloride of sodium, 0'45 chloride of magnesia, and 
 0'73 sulphate of lime. The water from the Lane shaft gave the 
 maximum of 11 '9 per cent, solids, containing S'S N"aCl, 0'51 MgCl 2 , 
 and 1-1 CaS0 4 .* 
 
 Certain results obtained in the treatment of the zinc precipitate 
 in the cyanide works of the Associated Mines have led the mill 
 manager, Mr. Grayson, to deduce the solubility of gold in sulph- 
 uric acid when tellurium oxide is also present, and thus to offer a 
 chemical theory for the alleged leaching of gold in the surface 
 ores. This explanation, as it stands, is questionable, because the 
 solubility of gold under the stated conditions is not known. 
 When, however, free chlorine is also present such solubility would 
 occur. f The telluric oxide, in the presence of salt and sulphuric 
 
 * For these figures I am indebted to the courtesy of Mr. Kichard Hamilton, 
 the mine manager. 
 
 f As pointed out by Mr. Richard Pearce, in a recent letter to the writer. 
 
12 
 
 acid, would take the part given in the laboratory to the black 
 oxide of manganese. The occurrence, therefore, of waters rich in 
 chlorides, of sulphuric acid derived from decomposing pyrites and 
 of tellurium oxide obtained from the oxidation of tellurides, are 
 all recognisable amid the conditions at Kalgoorlie, and thus afford 
 a theory which, while it has no very strong evidence to commend 
 it, is at least tenable from a chemical standpoint. 
 
 In many cases the supposed enrichment in depth can be easily 
 explained. For example, a shaft passes, in course of sinking, 
 from poor into rich ore. The lode, it would appear, has become 
 better in depth. The fact is, that the shaft was started off the 
 oreshoot, which has a pitch such as to bring it across the line of 
 the shaft at a certain level. The accompanying diagram will 
 illustrate this point. 
 
 MAIN SHAFT 
 
 It would be just as reasonable to argue that the ore occurred 
 in vertical bands because the levels pass in and out of the shoots. 
 In another suggestive instance a vertical shaft was sunk in a very 
 wide lode which is not quite perpendicular. The shaft was 
 started on the hanging wall side, where the ore is now known to 
 be always poor, and in depth it approached the footwall, where the 
 lode is richest. It was assumed, for a time, that an enrichment 
 in depth characterised the lode. The sketch (p. 13) will explain 
 this occurrence. 
 
 The idea of general enrichment in depth at Kalgoorlie arises 
 from an ignorance of the history of the early development of the 
 region. The discovery of the big ore-bodies was not made in the 
 infancy of the district, but came in the wake of that preliminary 
 digging which usually precedes systematic exploration. Patrick 
 Hannan pegged out the first claim on April 12th, 1892. At that 
 time nothing was known save the existence of a few superficial 
 deposits on the flat overlooked by Cassidy Hill and Mount 
 Charlotte. These deposits were of the kind termed " dry blowers' 
 patches." They may be described as the alluvium of a waterless 
 
13 
 
 country. Their substance varies. They may consist merely of 
 a few inches of sand and clay lying on the decomposed rock 
 surface, but elsewhere they may have a thickness of many feet, 
 
 SHAFT 
 
 LODE 
 
 and include a lower portion which is so compact as to be called 
 "cement." In the absence of the transporting power of running 
 water, the wind has been an active agent in sifting the debris 
 caused by that disintegration of the surface which is mainly trace- 
 able to the variation between the heat of day and the cold of night. 
 The finer rock particles are thus separated from the larger frag- 
 ments of hard quartz. And although the wind is but a feeble 
 agent as compared with the mountain stream, yet, owing to the pre- 
 valence of the constant and violent draughts of a high plateau, 
 such as the interior of West Australia, the sum of its activities 
 during long periods of time is capable of producing noteworthy 
 results. The miner imitates the ways of nature, and in default of 
 sluicing he winnows the dirt by a process known as " dry blow- 
 ing." The " dry blower " of West Australia is brother to the 
 "gulch miner" of California and the "alluvial digger" of Vic- 
 toria. 
 
 From the deposits which are thus accumulated gold has been 
 extensively won, and occasional patches of extreme richness have 
 been encountered. The heaviest gold is found resting close to the 
 underlying rock surface, and therefore, as in ordinary alluvial 
 mining, the working of these deposits often leads to the discovery 
 of the veins from which the gold was shed. Thus many " dry 
 blowers' patches " have been found adjacent to very valuable 
 lodes, and in the case of the alluvium of the Kalgoorlie flats 
 there were found small veins which led to the first raining. This 
 early mining was confined to that portion of the district which is 
 
14 
 
 close to the present town of Kalgoorlie, and which is distinct from 
 the scene of the great mining developments of the past two years, 
 2 miles further to the southward. The veins found in this 
 northern part of the goldfield were, as has been stated, small ; 
 they were also uncertain in behaviour, and generally poor. They 
 served nevertheless as an excuse for the taking up of numerous 
 leases and the subsequent flotation of mining enterprises of a 
 thoroughly worthless kind. Not one of these veins has as yet 
 become the basis of a successful enterprise, although they have 
 been followed by very extensive workings. In the meanwhile the 
 prospectors wandered further south, and found several rich patches 
 of surface dirt and cement, which led directly to the discovery of 
 one or two strong quartz croppings, on the evidence of which the 
 Great Boulder and other claims now famous were pegged out. 
 These quartz veins were larger than those previously worked in 
 the northern part of the field, but they were similarly poor and 
 uncertain, although this fact did not prevent the notation of the 
 Great Boulder Proprietary Company. The story of this splendid 
 mine is typical of that of several of its neighbours. The first 
 explorations were confined to a vein which outcropped in the 
 eastern part of the lease, and the shaft sunk upon it is the one 
 known as No. 3, or Gamble North's. The vein was soon proved to 
 be of no importance, becoming thin and poor at a depth of 75 ft. 
 A trench was then started to cut a big ironstone outcrop which 
 forms a hillock behind the present office. This ironstone reef was 
 found to contain only 12 dwt. of gold per ton, an amount too 
 small for profitable operations at that time. When, however, 
 the trench referred to was extended farther west it penetrated 
 another vein which had no outcrop. This proved to be the eastern 
 portion of the magnificent lode which subsequently gave such 
 great value to the mine. It was rich from the start. A wide open- 
 cut now bears confirmatory evidence, and the least observant can- 
 not help noticing that the stopes have been extended from the 
 underground workings up to the daylight. The section afforded 
 by the opencut exhibits the fact that 2 ft. of cement form a cap 
 over a lode nearly 20 ft. wide. The Great Boulder Perseverance 
 had a similar beginning. The first work was done on what is known 
 now as the old No. 1 Shaft, carrying a comparatively poor vein 
 which was abandoned when the rich lode in the neighbouring Lake 
 View Consols Mine was traced into the Perseverance ground. This 
 lode, which gave the value to this company's property, also failed 
 to outcrop. A big opencut now explains the reason to be similar 
 to that noted in the case of the Great Boulder. The surface 
 
15 
 
 workings on the Ivanhoe, Kalgurli, and other adjacent mines 
 exhibit similar conditions, big lodes capped by cement and long 
 lines of stopes breaking through into daylight. 
 
 In the meantime the extensive development of the goldfield has 
 afforded an explanation for the chequered nature of the early 
 explorations. It has been found that the quartzose lodes are 
 uniformly poor, and that the rich ones have a chloritic and mag- 
 nesian matrix which renders them susceptible to easy degradation 
 and erosion. Thus it is easy to understand the current misunder- 
 standing. The first veins worked were naturally those which had 
 outcrops. They outcropped because they carried much quartz and 
 were harder than the encasing country. They also happened to be 
 poor; therefore the first attempts at mining were unprofitable. 
 On the other hand the rich lodes had a composition into which the 
 carbonates of lime and magnesia entered largely, rendering them 
 softer than the rock enclosing them, and therefore they suffered 
 erosion at least as rapidly as the surrounding country. The 
 detrital deposits of the surface capped the tops of the rich ore- 
 bodies, and it was not until an accidental exploration had pierced 
 the cap of this " cement " that the first of the soft and rich lodes 
 was uncovered. The discovery of the others followed in due course. 
 
 The idea of an enrichment in depth was based on the fact that 
 the mines which were at first unprofitable became subsequently 
 marvellous ore producers. Careless observation and that wishing 
 which is father to much loose thinking served to bolster up an 
 erroneous idea, and to spread the statement that the ore became 
 richer at the water level. It is a matter which does not affect the 
 reputation of the really good mines so much as that of the forlorn 
 hopes, the poverty of which is excused by a lack of depth, thus 
 leading directly to the spending of much money on the foundation 
 of a fallacy. 
 
 From careful investigation and the sifting of much evidence I 
 am forced to the conclusion that Kalgoorlie is no exception to a 
 common experience, and that where rare enrichments occurred in 
 the sinking of a shaft, the fact can be traced to the structural rela- 
 tions of the ore deposits. I regret the conclusion. It would have 
 encouraged those in other regions had there at last been found a 
 district where nature had placed the best ore where man could 
 with most difficulty reach it, and, apart from its economic aspects, 
 the occurrence would have been one of great scientific interest. 
 
 Thus the tellurides, like rhodochrosite, tourmaline, zinc blende, 
 pyrites and a host of other supposed indicative minerals, must be 
 discarded as helps no better than the will-o'-the-wisp which leads 
 
16 
 
 the wanderer into a morass worse than the darkness itself. Better 
 no guide at all than a false one. 
 
 Shareholders and investors may be tempted to inquire whether 
 I would go so far as to deny the possibility of veterans in the 
 profession having such ability and experience as would permit 
 them to come to safe conclusions as to the prospective value of a 
 mine from a mere examination into the character of the ore. To 
 this I would answer that I believe the most experienced, the very 
 Ulysses among mining engineers, would be the first to emphatic- 
 ally disclaim such short cuts to the valuation of mines. A moil and 
 a 4-lb. hammer are of more use than a book full of sounding theories ; 
 a careful sampling of the workings is of more immediate utility 
 than a treatise on mineralogy. Successful mining must be based 
 on facts ; all the rhetoric and fond imagining in the world cannot 
 alter them. It is the province of the mining engineer to deter- 
 mine the facts, to get alongside them, as Huxley would say, and 
 when a theory comes floating by leave it, as Joseph left his coat 
 in the hands of the harlot, and flee. Experience has proved thab 
 indicative minerals are delusive ; so let them go. But the mineral 
 contents of an ore, though they have no bearing on the mining, 
 decide its metallurgical treatment, and therefore need careful 
 examination. The importance of the character of the ore from 
 this point of view is too often overlooked by those enthusiastic 
 mineralogists who permit themselves to make the most sweeping 
 deductions on matters of much greater uncertainty. 
 
 Careful sampling is worth a bushel of suppositions, and the 
 painstaking determination of the working costs is better than any 
 amount of geological generalisation. Mining is not a scientific 
 pursuit, although at times it may to the observant have seemed to 
 be either that or one big insanity. But mining is an industry. 
 The good sense which financial men have of late years contributed 
 to its operations has done much to bring it from a windy misti- 
 ness to the solid footing of sound business The main purpose 
 is not to develop the waste places of the earth, nor to spoil the 
 scenery of the mountainous ones, but simply to win a profit by 
 extracting ores out of the ground. It is a plain matter of profit 
 and loss. On the one side is the value of the gold in the ore, and 
 on the other is the cost of the processes needed to obtain it. To 
 arrive at the former there is only one way, namely, to sample the 
 workings systematically. The result will be reliable in propor- 
 tion to the care taken. Any shirking of difficult places in the 
 mine, any avoidance of hard portions of the vein, any assistance 
 from untrustworthy hands, will vitiate the resulc. Against this 
 
17 
 
 must be placed the costs of operation. Here it is that experience 
 is needed. The sampling is largely mechanical, like ordinary- 
 assaying", and requires patience and care more than anything else. 
 In the estimate of the costs there must be included many items of 
 expenditure, such as the breaking of the ore, the development 
 work, the equipment, the milling, the management ; and to arrive 
 at these the previous actual charge of mines is the only proper 
 preparation. Then comes the question of the quantity of ore avail- 
 able or likely to become available by further exploration. This is 
 the pans asinorum of mining. That which some describe as ore in 
 sight is often really ore out of sight. The over sanguine estima- 
 tion of ore reserves has rained more enterprises than all the bad 
 management and over- capitalisation of which complaints are daily 
 made. It is ever a difficult matter and requires a cool judgment, 
 wide experience, and a careful investigation into the circum- 
 stances and structure of each particular mine. 
 
 When the value and tonnage of the ore available have been 
 arrived at, and when working costs have been determined, then 
 the engineer has the greater part of the evidence needed to submit 
 to the client whom he is advising. The other data which will 
 influence an opinion are more variable in their character. The 
 geological conditions may affect the distribution of the ore bodies 
 and, consequently, the cost of mining, and the mineralogical com- 
 position of the ore may determine the expense of milling. As 
 such they mast not be overlooked, but the padding of a report 
 with a large amount of geological disquisition, where it is not 
 necessary to a comprehension of the facts of the case, is very 
 nearly an impertinence, seeing that it is not expected that it will 
 be understood by the person or persons for whose guidance the 
 report is written. 
 
 In concluding this contribution I would express the hope that 
 this paper may lead to a useful discussion. If there are any tech- 
 nical men who seriously entertain the idea of an enrichment in 
 depth due to the leaching of gold in the oxidised ores, then it would 
 be of much service to the industry if they would frame a defence 
 and an explanation of views which daily experience must other- 
 wise condemn as nonsense. Nor in denouncing one generalisation 
 would I make the equally grave mistake of advocating its opposite, 
 namely, that all mines must necessarily become poorer in depth. 
 There may be causes, founded on geological structure, why a 
 change in the value of the ore in a vein may take place in any 
 direction, upward or downward, in dip or in strike, and it is an 
 undoubted fact that there have been instances where the deepening 
 
18 
 
 of the workings lias led to the discovery of new ore bodies. Bendigo 
 is a telling illustration.* The gold-bearing quartz occurs along the 
 anticlinal axes of sedimentary rocks. In sinking, a succession of 
 saddle formations is penetrated. ~No single one of these has any 
 not able -vertical extent, yet the series as a whole is wonderfully 
 persistent. This explains why the last resort of a perplexed mine 
 manager is to advise the sinking of the main shaft. At Bendigo 
 the advice is well founded, but when the managers from this dis- 
 trict go to West Australia and recommend deeper exploration 
 every time they encounter poor ore, they do so without regard to 
 the total unlikeness of the conditions. Again, it cannot be denied 
 that in certain regions alternations of comparative richness and 
 poverty appear to coincide with the penetration of the workings 
 through successive zones of rock. The Gympie district is a case 
 in point. There the veins cut through a series of shales, lime- 
 stones, conglomerates, and sandstones, amid which there are 
 several beds of black slate. The gold occurs in paying quantity 
 only when the veins are traversing the slates. Every district 
 deserves a study unbiassed by the record of its neighbours ; each 
 mine must be taken on its merits and inspected without prejudice. 
 It is, however, one thing to examine a mine with the assumption 
 that gold veins in general become enriched in depth, and it is 
 quite another thing to recognise that while it may occur in a par- 
 ticular case, it is an expectation which experience does not justify. 
 When, however, such enrichment or impoverishment does occur, 
 experience suggests to us that its cause is to be sought for rather 
 in the geological structure of the encasing rocks than in the 
 merely coincident presence of certain minerals found associated 
 with the gold. 
 
 * See " The Bendigo Goldfield," by the writer, in vol. xx, Trans. Amer. Inst. 
 of Mining Engineers. 
 
 HARRISON AND SONS, Printers in Ordinary to Her Majesty, St. Martin's Lane. 
 
Abstract of Proceedings. Vol. VIII. 
 
 "The Cripple Creek Goldfield,' 
 
 A PAPER READ BEFORE THE 
 
 INSTITUTION OF MINING AND METALLURGY, 
 
 ON WEDNESDAY, IOTH NOVEMBER, 1899, 
 
 BY 
 
 T. A. RICHARD, M.Inst.M.lVL, State Geologist of Colorado. 
 
 Bonbon : 
 
 INSTITUTION OF MINING" AND METALLURGY, 
 BROAD STREET HOUSE, B.C. ' 
 
" The Cripple Creek Goldfield." 
 By T. A. RICKARD., M.Inst.M.M., State Geologist of Colorado. 
 
 INTRODUCTORY. 
 
 THE romantic history of mining records many names which had an 
 odd sound until fame familiarised them. Ballarat, the Coeur 
 d'Alene, Bendigo, the Yuba, Leadville, Broken Hill, Klondyke, and 
 Kalgoorlie, for example, have been words to conjure with, although 
 in the beginnings of the particular mining districts designated by 
 them they were spelt with difficulty and pronounced with un- 
 certainty. In 1892, when Cripple Creek began to be talked about 
 among the clubs and banks of Denver, as a new locality where im- 
 portant discoveries of gold had been made, the name seemed only 
 provocative of derision. It is said to have originated from the fact 
 that at a certain point on the course of the little stream there was a 
 morass in which straying cattle wandered and, in their efforts to 
 extricate themselves, were occasionally lamed. So says one of the 
 survivors of the band of men who once tended the herds that 
 grazed on the hills now pierced with many shafts. However, the 
 name needs no apology to-day, the magic baptism of golden dis- 
 covery has made it sound as alliterative and impressive as the most 
 exacting historian could demand. 
 
 The locality of the great goldfield is full of romantic suggestion, 
 because its very situation, overshadowed by the granite battlements 
 of Pike's Peak, recalls the fact that it has fulfilled the expectations 
 of an older generation. The wave of immigration which, after the 
 financial panic of 1857, swept westward until it broke against the 
 ramparts of the Rocky Mountains, was the vanguard of a new 
 civilisation destined to dispossess the Indian and the buffalo. In 
 their progress across the prairies, the pioneers of that advance ever 
 sought with shaded eyes for the first glimpse of the beacon moun- 
 tain whose white crest on the far horizon gave promise of the land 
 of gold. That beckoning guide was the granite peak which Lieut 
 
 6 
 
Zebulon Pike had reconnoitred in the first years of the century. 
 " Pike's Peak or bust," the motto of the adventurers of 1857 and 
 
 1858, sounds but mock heroic in our ears, but it expressed something 
 of the mingled humour and daring of the men who first pierced the 
 unknown wilderness which was then the borderland of the territory 
 of Kansas. 
 
 The immigration which marked the beginning of Colorado's 
 history, was thus known as " the Pike's Peak excitement." The 
 rallying call of the pioneers expressed a delusion. No gold 
 discoveries of any moment were made at that time in the 
 canyons or on the hills surrounding the peak. It was in the 
 mountainous region 70 miles northward, now known as Gilpin 
 County, that the first beginning was made. On the 6th of May, 
 
 1859, John Hamilton Gregory found the outcrop of the lode 
 which still bears his name and the working of which celebrated the 
 commencement of the mining industry of Colorado. This discovery 
 led to the development of Gilpin county, which was contempor- 
 aneous with the opening up of Clear Creek and Boulder. In 1860 
 the placers of California gulch and Breckenridge were discovered ; 
 in 1875, Leadville; in 1879, Aspen; in 1882, Eed Mountain; in 
 1889, Creede; and so on, until the mining districts of Colorado 
 were distributed all over its wonderful complex of mountain land. 
 
 Amid all these rapidly succeeding discoveries, and the extra- 
 ordinary activity which followed each of them, the silence of the 
 quiet hills surrounding Pike's Peak remained unbroken. Suddenly, 
 in the spring of 1884, rumours were circulated of a great discovery 
 south of the peak. During the darkness of an April night a horde 
 of prospectors stole swiftly away in obedience to vague hints which 
 had been scattered among the saloons of Leadville and surrounding 
 camps. Each party aimed to be the first on the ground. The 
 dawn of the next day found an excited crowd of four thousand men 
 gathered at the base of Mt. Pisgah. The incident has since become 
 known in local history as the Mt. Pisgah fiasco. 
 
 Among the hills which like a flock of sheep cluster around the 
 southern base of Pike's Peak, there is a dark cone standing in soli- 
 tude among its smaller brethren. This is Mt. Pisgah. In 1884 
 the miners who rushed thither could find no gold in workable 
 quantity save in the prospect holes made by the original locators. 
 Salting was suspected, the man who had instigated the rush was 
 conspicuous by absence, an accomplice was caught with a bottle of 
 yellow stuff in his pocket. It was not whisky, but its modern 
 antidote, the chloride of gold. Man had endeavoured to remedy 
 nature's seeming niggardliness and the rock had been artificially 
 
enriched. Angry feelings found vent in threats of lynching, but in 
 the failure to lay hands upon the real perpetrators of the fraud, 
 the affair broke up in a big picnic and a general drunk. A little 
 digging had been done, one or two veins were uncovered, but the 
 comparative poverty of the ore only added bitterness to the general 
 disappointment. The crowd disappeared as quickly as it had come. 
 The hillsides resumed the quiet aspect of the cattle range for which 
 they seemed best fitted. The incident was over. 
 
 The vicissitudes of mining are proverbial. No district illus- 
 trates it more forcibly than Cripple Creek. It provokes one to 
 cynicism to think how near the deluded prospectors of 1884 were 
 to the eve of big discoveries. The dark front of Mt. Pisgah now 
 overshadows the very streets of the town of Cripple Creek, with its 
 20,000 inhabitants, and on the ridges opposite the lines of smoking 
 chimneys bespeak a long succession of productive mines. 
 
 Not until 1893 did Cripple Creek come to the front; two years 
 before, the name had begun to be mentioned in mining circles, but 
 the Mt. Pisgah excitement had discredited the district and the 
 contemporaneous discoveries of large silver lodes at Creede, at the 
 headwaters of the Eio Grande, diverted attention for a time. The 
 closing of the Indian mints, in June, 1893, prostrated the silver 
 mining industry, which at that period was far more important to 
 the state than its gold production.* As soon, however, as the silver 
 market became disorganized, all the activity of a most energetic 
 mining community was concentrated upon its gold resources. The 
 experienced men of Leadville and Aspen, where silver-lead mining 
 predominated, turned with the energy of despair to the new gold- 
 field which previously they had pooh-poohed. A new impetus was 
 given to exploratory work, Cripple Creek underwent rapid develop- 
 ment and the result soon became apparent in the opening up of 
 several rich mines and in a production of gold which sprang from 
 $583,000 in 1892 to $2,100,000 in the year following. 
 
 A few notes regarding the events which led up to the present era 
 of prosperity and productiveness will fittingly close this introductory 
 history. For several years before 1891 prospectors had wandered 
 over the hills from Colorado Springs and Florissant, treading in the 
 footsteps of the men of 1858. Indeed, there is a story current in 
 the camp to this day that on the top of Bull Cliffs,! above the Victor 
 
 * In 1892, Colorado produced 26,350,000 oz. of silver, valued at $23,082,600, 
 and 256,410 oz. of gold, worth $5,300,000. In 1898 the State producer) 
 1,138,584 oz.of gold, worth 823,534,531. 
 
 t The names of several hills and gulches are reminders of the fact that the 
 district was once given up to the quiet herds of cattle. 
 
 6 2 ' 
 
Mine, there was found a shallow shaft, which had been dug by the 
 pioneers of the Pike's Peak excitement. Among the earliest of the 
 gold-seekers was Robert Womack, who once owned a small ranch in 
 the district. He sold it to Bennett and Myers, the proprietors at 
 that time of the cattle range, which covered a large part of the area 
 now forming the environs of the town of Cripple Creek. For many 
 years, between 1880 and 1890, Bob Womack lived in the district, 
 doing occasional work for Bennett and Myers, and spending his 
 spare time in prospecting. He had previously had some experience 
 in Gilpin County, and knew gold ore when he saw it. In the course 
 of desultory digging, he found several veins, and when he would 
 turn up at intervals, at Colorado Springs, he exhibited pieces of 
 float (surface ore) as evidence of his discoveries ; but having a repu- 
 tation for honesty rather than shrewdness, his statements made little 
 impression. For many years he worked on a hole in Poverty Gulch 
 without staking a claim in proper form. There seemed no need to 
 do so ; no one came to disturb him ; the whole hill country was at 
 that time fenced in so as to serve as a summer range for cattle. The 
 cowboys and herdsmen looked good-naturedly at Bob's digging, but 
 did not consider it of any moment. In December, 1890, E. M. de 
 la Vergne and F. F. Frisbee came up from Colorado Springs to 
 prospect. George Carr, who was in charge of the ranch belonging 
 to Bennett and Myers, showed them around the district. The hills 
 were under snow, and only a few bare spots permitted of any pro- 
 specting. On Guyot Hill, in Eclipse and in Poverty Gulches, they 
 found evidences of gold veins, and samples were taken away. These 
 averaged about 2 oz. of gold per ton. Encouraged by their first 
 visit, De La Vergne and Frisbee returned early in February, 1891. 
 They found Bob Womack at work in Poverty Gulch. He had sunk 
 a shaft to a depth of 48 ft., and encountered good ore. The claim 
 he had pegged out was called the " Chance," and a number of 
 stakes indicated that he had relocated it six years in succession 
 without recording the fact or complying with the conditions of the 
 mining law in regard to the amount of assessment work required 
 annually. When he found the newcomers were making inquiries, 
 he relocated the claim as the " El Paso," and De La Vergne, finding 
 another lode, heavy in iron pyrites, to the west of Womack's vein, 
 located a claim, which he called the " El Dorado." It was recorded 
 a few days later, and in the certificate the district was called for the 
 first time by the name which it still bears, Cripple Creek. Although 
 these locations had been made, little actual mining was done upon 
 them for some time afterwards. Womack absented himself. Frisbee 
 saw that there was a good deal of surface ore which could easily 
 
be removed, so while Womack was away, he sent 1,100 Ib. by wagon 
 to the Pueblo Smelting and Kefining Company, who gave returns at 
 the rate of $200 per ton. This was in August, 1891. Frisbee 
 induced Womack to give him a bond and option on the El Paso for 
 85,000. Shortly afterwards it was transferred to Messrs. Lennox 
 and Giddings, who still own it, as a part of a very successful mine, 
 the Gold King. 
 
 In May, Frisbee and De La Vergne happened to be at Colorado 
 Springs and met "\V. S. Stratton, to whom they showed certain 
 assays of ores brought down by them from Cripple Creek. Stratton 
 was a house-builder and carpenter by trade, but in the intervals of 
 his regular occupation he had been prospecting for fully 20 years 
 previous to this date ; he had learnt the use of the blow-pipe, and 
 was familiar with the outlines of mineralogy and geology, in fact 
 an energetic, well-informed man, thoroughly equipped for prospect- 
 ing work of any kind. At that time he had been searching for 
 cryolite, a mineral from which the metal aluminium is obtained, 
 and had a camp on the Little Beaver, on the Cripple Creek side of 
 Pike's Peak. After the meeting with De La Vergne and Frisbee, 
 he went to Cripple Creek and camped there. Stratton met Bob 
 AVomack and went around seeing the little work done by the latter 
 and his associates. Among those who were prospecting in the 
 vicinity was Dick Houghton, an old mountaineer, prospector, and 
 specimen hunter, whose labours have enriched many museums. One 
 day Houghton brought down a piece of rock from the Lone Star 
 claim on Gold Hill, and, meeting Stratton in Poverty Gulch, he 
 told him he had found some galena (the sulphide of lead). Stratton 
 examined it with his magnifying glass and expressed doubts as to 
 its being galena, and in looking at the ore he saw little cubes of 
 rusty gold, one of which had been scratched by being carried in 
 Houghton's pocket so as to expose a bright surface. They went 
 down to Stratton's tent, and he pulled out his blow-pipe and made 
 a test which proved that it was gold. Neither of these men knew 
 at that time that the bright silvery mineral, which Houghton 
 thought to be galena, was sylvanite, the telluride of gold and silver. 
 It is not known who first recognised the tellurides of Cripple 
 Creek, but there is a story that a miner made a camp fireplace with 
 some pieces of rock which carried this silvery mineral, and that the 
 heat of his cooking operations roasted the ore so as to bring out the 
 fact that it carried gold. Se non k vero e ben trovato. Stratton 
 went up and located the claim adjacent to Houghton's; it was 
 named the Gold King, and is now a part of the Gold and Globe 
 property. On the 5th of June, Stratton, accompanied by Fred 
 
6 
 
 Troutman, went to the ridge above Battle Mountain, and seeing 
 the willows at the head of Wilson Creek (where now the town of 
 Goldfield is situated), they inferred the presence of water. They 
 descended the hill and got . a drink ; then climbing the hill behind 
 the spring, they found loose pieces of rock, one of which was 
 broken open and found to be smothered in gold. The owner of 
 the Independence says that this was the only time he got really 
 excited. Camp was moved from Cripple Creek next day and 
 pitched close to the spring. A search was begun for the lode which 
 had shed so goodly a float. Trenches were dug ; but Stratton had 
 an idea at this time that veins with a north and south direction 
 were the ones which carried rich ores, and so his trenches were dug 
 at right angles to this course, with the result that they paralleled 
 the veins actually existing there, and since developed into the 
 Legal Tender, Lillie, and Vindicator Mines. They found nothing. 
 An old ranchman, Billy Fernay, came along about this time and 
 brought some float which he had found on the hill below, now 
 called Battle Mountain. Stratton liked the look of it, so Fernay 
 located it for Stratton, Troutman, and himself, calling it the Black 
 Diamond. It is now one of the claims included within the territory 
 of the Portland Mine. Next day Stratton went down to see the 
 vein and tried to make the course of it accord with the line of the 
 ridge. This led him down the hill to a big outcrop of granite. It 
 was the Independence vein, which had already been seen by many, 
 including nearly all of those whose names have been mentioned. 
 The path from one ranch to another went close by, and all the 
 cattle men who had any idea of prospecting had looked at it. 
 Every one had condemned it as worthless granite. Fernay pointed 
 it out to Stratton, but he also did as the others had done. On 
 examining the outcrop he remarked the absence of any metallic 
 mineral and of vein quartz such as he had been accustomed to in 
 the San Juan region, and therefore concluded that it was an 
 unlikely looking rock. And so it really was, for it was granite 
 without the ordinary gold-bearing minerals visible in it, differing 
 indeed from the granite of the dome of Pike's Peak in being less 
 fresh in appearance, brown instead of pink, and marked by dark 
 spots where the mica had been decomposed. Some of it yet 
 remains in place, inviting the observation of those who may wonder 
 why the great lode was so long disregarded. Stratton overlooked 
 it, but not irretrievably. Two days later, John R. McKinnie, who 
 was one of the first prospectors in the district, came to their camp, 
 and so did Charlie Love, a ranchman from Beaver Park, who had 
 pointed out the big outcrop to many of the prospectors. The latter 
 
asked McKinnie if he had seen it, but the matter was allowed to 
 drop. Stratton remembered the incident when, on the morning of 
 the Fourth of July, he was at Colorado Springs, whither he had gone 
 with five samples for assay. The assays gave only three or four 
 dollars per ton at the best, notwithstanding that he had obtained 
 good results by panning. It suddenly occurred to him that the 
 granite outcrop must be the lode. He had found gold in the loose 
 fragments of porphyry lying upon the south face of Battle Mountain 
 near the granite outcrop, but he had been unable to trace its source 
 to any vein in the porphyry formation. Acting on the impulse, he 
 took a horse immediately, and on arrival found Troutman ready 
 to leave in order to celebrate the Fourth at Colorado Springs. 
 Stratton made two locations : the Washington and the Independ- 
 ence. I doubt if any man ever celebrated the Fourth of July to 
 better advantage. Some pieces of the outcrop of granite ore were 
 broken, and Troutman took them to be assayed at the Springs, 
 while Stratton awaited the result. Troutman returned on horse- 
 back next day with the assay certificate, proving the ore to be 
 worth |380 per ton ! The rest of the story is simple. It records 
 the steady development of one of the richest mines ever uncovered 
 by the miner's pick. 
 
 I might go on to tell the story of the Portland and that of other 
 mines, now celebrated, which made beginnings no less romantic ; 
 but the above few notes will give an idea of the manner in which 
 the Cripple Creek goldfield was first opened up. Let me emphasize 
 the fact that it was not the result of accident, nor the work of 
 ignorant men, but it was the accomplishment of experienced miners 
 who knew what they were doing, and had the energy and ability to 
 do it. It is now a part of the true and romantic story of beneficent 
 endeavour which turned the barren prairies into the granary of a 
 continent, and made the snowclad mountains an empire whose tribute 
 of gold and silver transcends that of the Caesars'. 
 
 PHYSICAL FEATURES OF THE DISTRICT. 
 
 The known gold-bearing portion of the district covers an area 
 four miles long by three miles wide, occupying a group of hills 
 which rise from 300 ft. to 1,000 ft. above the general surface, 
 and have an average altitude of 10,500 to 11,000 ft. above the sea. 
 The drainage of the region flows into the Arkansas river, whose 
 gateway into the plains is at Canon City. The general slope is 
 southward, and the sunny aspect incident to this configuration of 
 the surface has caused the hill-sides to be clad with sufficient grass, 
 
8 
 
 and rendered them, at one time, despite the high altitude, a good 
 pasturage for cattle. 
 
 Few mining camps have so picturesque a situation, and Cripple 
 Creek is further notable because the picturesque is not obtained at 
 any sacrifice of accessibility. The beauty of the panoramic view to 
 be obtained from most of the mines is not due to mere ruggedness 
 or to the ordinary grandeur of a mountainous country ; it is trace- 
 able to a position upon the slopes flanking Pike's Peak, which per- 
 mits of an uninterrupted view of snow-clad ranges a hundred miles 
 away. It is a panorama rather than a picture. In front are hills 
 like giants tumbled in troubled sleep, whose feet touch the plateau 
 of the South Park. To the left are the Arkansas hills that confine 
 the river of the same name to its tumultuous gorge ; further south 
 is the Wet Mountain valley, and beyond that the long magnificent 
 serrated range of the Sangre de Cristo, telling of the shattered dream 
 of Spanish conquest, of which no trace now survives, save in the 
 occasional name of a peak or a stream. These remind a practical 
 age of the priestly warriors and the warlike priests who once sought 
 to win the golden treasures of a land whose aboriginal people have 
 almost passed away. The wind blows the snow of the Sangre de 
 Cristo into streaming banners, and the clouds like vanquished legions 
 sweep across the far horizon. Turning northward, the valley of the 
 Arkansas can be seen dividing the mountains which overlook Lead- 
 ville. Further to the right are the beautiful Kenosha hills, at the 
 headwaters of the Platte, and beyond them are snow-clad peaks 
 rising above 14,000 ft. The details of the view are lost in the vast- 
 ness of it, which impresses the observer no less because he is sur- 
 rounded by a noisy murmur of trains, steam whistles, wagons, and 
 machinery, which tell of the activity going on about him. Still, 
 there is a nobility of human endeavour and successful achievement 
 no less impressive than the beauty of snow-clad peak and silver 
 summits. 
 
 The physical condition of the surface had much to do with the 
 chequered history of the district. Owing to the southern exposure 
 and the comparative absence of a protecting growth of trees, the 
 rocks, which mostly possess a fissile structure, have been shattered 
 by frost so as to overspread the solid formation with a thickness of 
 debris to which the tufted grass has given a further covering. 
 Water, owing to its expansion between 4 C. and the freezing point, 
 is a ceaselessly destructive agent. When it penetrates the cracks 
 and crannies of the rocks it serves as a wedge shattering their stony 
 substance with a resistless power. The heat of day and the 
 cold of night, the warmth of summer and the snows of winter, alike 
 
9 
 
 aid this disintegrating process. A high altitude and a south slope 
 afford the conditions most favourable to such action. Thus it came 
 about that the district of Cripple Creek is largely covered with the 
 shattered rock which the miners call " wash," incorrectly, however, 
 because it is not composed of rounded waterworn material, but of 
 angular fragments which, if not in place, are not far from their 
 original position, having slid down the hill slope in obedience to the 
 laws of gravity. This shattering of the rock-surface has caused one 
 very important and, in Cripple Creek's case, far-reaching result. 
 There are no outcrops. Ordinarily, the veins of gold-ore stand 
 above the surface with that boldness which caused the Australian 
 miner to term them " reefs," and the Calif ornian to call them 
 " ledges." The ore, as will be seen when discussing the geology of 
 the gold-field, is essentially mineralised and enriched rock, compara- 
 tively devoid of the quartz composing the typical lodes of other 
 districts in America or Australia, and consequently it shares with 
 the rock the tendency to undergo easy shattering. Solid veinstone, 
 therefore, rarely survives amid the general disintegration, the out- 
 crop of the Independence being a very notable exception. 
 
 The first discoveries in mining are usually due to the finding of 
 outcrops ; in the absence of them, deep explorations are rarely under- 
 taken. Deep ravines often afford good natural sections of the rock 
 formation. The Cripple Creek district was as deficient in the one 
 feature as the other. The absence of steep declivities and con- 
 sequent rock faces was characteristic of the pastoral landscape, and 
 the angular debris covering the rounded hildsides made digging 
 difficult. For these reasons, although the district was traversed by 
 many thousands of prospectors at successive epochs, the existence 
 of rich lodes was not surmised until a very recent date, and many 
 experienced miners failed of success at first because they encountered 
 conditions unfamiliar to them. Among the early arrivals, in 1891 
 and 1892, were miners from Gilpin, Leadville, and Aspen, men of 
 knowledge in their own habitat, but unable to understand the 
 peculiar vein structure which they saw at Cripple Creek. It was 
 the adverse opinion of these men, rather than the views of geolo- 
 gists or scientific observers, which injured the reputation of the 
 goldfield in the beginning of its development. 
 
 THE GEOLOGY OF THE GOLDFIELD. 
 
 The intimate relationship between geological structure and ore 
 occurrence has nowhere been more forcibly emphasised than in 
 Colorado. This is largely due to the labours of the United States 
 
10 
 
 Geological Survey, whose monographs on Leadville and Cripple 
 Creek (particularly the former; have been of inestimable assistance 
 to the mining industry. 
 
 The dissemination of accurate knowledge regarding the geology 
 of mining districts has been aided by the increasing simplicity and 
 clearness of the language employed to convey it. There was a 
 time when geological data were expressed through the distorted 
 medium of six-syllabled words, and scientific men appeared to follow 
 the example of the hierophants of the ancient temples, who spoke 
 to the populace only in language incomprehensible to them. The 
 application of science to commerce, of geology to the industry of 
 mining, has led to the recognition of the fact that to talk to busi- 
 ness men in a hybrid Greek-Latin jargon, is only an impertinence. 
 If mining be not a business, it is a vain delusion. The language 
 of technical science when it bears upon business must be made 
 intelligible to business men, otherwise it will remain a mere abra- 
 kadabra of speech.* 
 
 The mines of Cripple Creek are situated in a complex of vol- 
 canic rocks, occurring amid the mass of granite whose culminating 
 point is Pike's Peak. These volcanic rocks found a passage through 
 the underlying granite in the comparatively recent period known 
 to science as the Miocene, an early part of the last of the three 
 great subdivisions of geological time. The granite was formed in 
 the very dawn of time, out of the substance of it the mighty foun- 
 dations of Pike's Peak were upbuilt and the crest of the mountain 
 was chiselled. It is the basal rock of the region and at one time 
 probably formed the floor of the ancient seas which received the 
 sediments now composing the sandstones and limestones flanking 
 the Front range. The granite is of a particular type, known, 
 because of its prevalence in this locality, as the Pike's Peak granite. 
 It is coarsely crystalline and its three ingredients, the minerals 
 quartz, mica, and felspar, are easily distinguishable by the unaided 
 eye. A beautiful red tint, mainly due to the colour of the felspar, 
 characterises it and renders it recognizable by the least observant. 
 
 * I have in the present contribution laid myself open to the criticism of 
 technical men by avoiding the use of technical terms and by a seemingly 
 unnecessary translation of those the use of which was unavoidable. It may 
 seem to be a work of supererogation, yet because an institution of mining and 
 metallurgy does its most useful work when it transmits the recorded observa- 
 tions of its members to those who are engaged in the industries the benefit of 
 which it promotes, therefore it seemed better to me to give explanations 
 needless to scientific men than to be unintelligible to those to whom these 
 observations may be of interest, however slight, and of use, however insig- 
 nificant. 
 
11 
 
 Long subsequent to the formation of the granite and the sedi- 
 mentary rocks which were laid down upon it, there began an 
 elevatory movement supposed to be traceable to the re-adjustment 
 of the earth's exterior to its cooling and shrinking interior. 
 Accompanying this movement there occurred a general fracturing of 
 the rocks thus affected, so as to permit volcanic matter to force a 
 way upward, after the manner of water rising through cracks in 
 the overlying ice. The volcanic rock thus brought to the surface 
 of the granite slowly filled the hollows of its uneven surface, and 
 spread over a large area since then diminished by the patient forces 
 of atmospheric erosion, which during the long period of time 
 separating the Miocene from the present day, have slowly sculptured 
 the hills and valleys of the district. 
 
 A glance at the coloured geological map of the goldfield exhibits 
 a great variety of volcanic rocks. The principal of these is ande- 
 site breccia.* The very nature of the breccia suggests the violence 
 of the volcanic action which brought it to the surface of the granite. 
 The miners call the breccia " porphyry " from its apparent resem- 
 blance to the rocks of that class with which they were previously 
 familiar in the Leadville and in the Gilpin County mines. The 
 porphyry of Leadville is quartz-felsite, that of Gilpin is quartz- 
 andesite. Porphyry! is an adjective-noun and refers to the struc- 
 ture rather than to the composition of a rock, so that there is 
 " granite-porphyry," " diorite-porphyry," " andesite-porphyry," &c., 
 the term being applied to rock of igneous origin in which particular 
 minerals are distinguishable amid the ground mass of the rock so as 
 to give it a speckled appearance. The Cripple Creek breccia has 
 this appearance, but it is due to the fact that it is made up of a 
 heterogeneous mass of rock particles of every size, from the most 
 minute powder to fragments as large as a man's head. These con- 
 
 * "Andesite" is derived from Andes, the mountain range where this rock 
 is especially prevalent. "Breccia" is a word of Italian origin, and means 
 " broken." It is a term applied to rocks which are made up of fragmentary 
 material. 
 
 t " Porphyry " comes to us through the Greek word porphyra, signifying 
 purple. It was first xised to designate a beautiful rock of this type which the 
 Eoinans obtained from the quarries of Grebel Dokhan, on the shores of the Eed 
 Sea. This original "porphyry" called by the Italians " porfido rosso antico," 
 had, according to Zirkel, a beautiful blood-red ground mass speckled with 
 small snow-white and rose-red crystals of felspar. But the first meaning of 
 the term which depended on the colour has long been lost in another meaning 
 which refers to the structure. A rock is a " porphyry," or, more correctly, 
 is " porphyritic," when some particular constituent mineral, very often felspar, 
 stands out well defined from the general ground-mass, as in the western 
 miners' familiar " bird's-eye porphyry." 
 
12 
 
 sist mainly of andesite, but the other rocks are included, especially 
 near the edges of the volcanic vent. Some of this material is 
 mere volcanic dust, called tuff,* which, when consolidated under 
 pressure and cemented by silicious waters, becomes compacted into 
 a dense hard substance difficult to distinguish from a true crystal- 
 line rock ; so that it is not to be wondered that the miners often 
 label it with an incorrect name. 
 
 The breccia lies in the uneven hollows of the ancient surface of 
 the granite, and probably fills a large part of the vent through 
 which it was ejected. The thickness of the breccia has not been 
 proved, nor has the exact position of the vent been discovered, 
 although there is evidence, in the composition of the rocks, indi- 
 cating the approximate position of it to be just west of the town of 
 Goldfield and near the locality covered by the Hull City placer. 
 The mine workings have shown the thickness of the breccia to be 
 over a thousand feet in several places ; but as these are for the most 
 part near the edge of the mass there is every probability that the 
 maximum depth of this formation is several times one thousand feet 
 in the vicinity of the point of extrusion. 
 
 The accompanying sketch of the Cripple Creek volcano is largely 
 diagrammatic, but it will serve to convey a general idea of the 
 geological structure of the district. 
 
 The breccia is penetrated and traversed by later volcanic rocks, 
 of which phonolitef is the most important in its relation to the 
 occurrence of ore. Until recent years phonolite was not known as 
 a rock species save as forming the Wolf rock in Cornwall, and, 
 therefore, its association with great mineral wealth at Cripple Creek 
 has been one of the most interesting features of the development of 
 that district. The phonolite occurs for the most part in dykes, that 
 is to say, in approximately vertical sheets which traverse the older 
 formations, the granite and the breccia, in various directions, and 
 are probably united, at depths far beyond the reach of human ex- 
 ploration, to larger masses of rock having a similar composition, 
 just as the cracks in ice are filled with a liquid similar to that 
 beneath. 
 
 These dykes follow such lines of weakness in the older rocks as 
 
 * " Tuff " comes from the Italian tufa. Vesuvius is responsible for the 
 Italian nomenclature of many volcanic products. 
 
 f " Phonolite " is derived from two Greek words, phone, signifying sound, 
 and lithos, meaning stone. It owes this name to the fact that it rings when 
 struck by a hammer. This is due to its hardness and close texture. It is also 
 called " clinkstone." The essential constituents of phonolite are nepheline and 
 the glassy variety of felspar termed sanidine. 
 
13 
 
 were developed [into fractures during those periods when the rocks 
 underwent strains, the latter being considered to be the result of 
 the slow wrinkling of the earth's crust due to its readjustment over 
 
 C f? 
 
 FIG. 1. 
 
 PLAN 
 
 a cooling and shrinking interior. The phonolite rose in a mobile, if 
 not molten, condition through the fractures thus formed after the 
 manner of water rising through the cracks in [the overlying ice. 
 The structural conditions thus created gave a direction to the sub- 
 sequent circulation of underground waters. The deposition of ore 
 
14 
 
 is the result of such circulation, the mineral-bearing solutions being 
 the vehicle by which the metals are leached out of the rocks and 
 laid down elsewhere in such a concentrated form and within such a 
 distance of the surface as to render them valuable to man. The place 
 of origin is surmised, but vaguely, as being deeper than our deepest 
 mines, and the place of deposition is not always the place where the 
 miner finds it. Lines of weakness, healed and strengthened by the 
 cementing effects of hot igneous rock, in the form of dykes, afford 
 new lines of lesser resistance, parallel to the old ones and along the 
 contact of the two rocks of unlike hardness and texture. For this 
 reason ore-bearing veins so often accompany dykes. They do so at 
 Cripple Creek. 
 
 Before venturing upon the details of vein structure in this par- 
 ticular district, it will be well to preface such a description by a 
 few general remarks upon the subject as viewed from a wider 
 standpoint. 
 
 The mines of Cripple Creek afford excellent illustrations of the 
 teachings of modern geology, and emphasise the incorrectness of 
 the hasty generalisations of Sandberger and others before him. It 
 is, of course, foolish to deride even theories which are now laid on 
 the shelf, after they have served the purpose of quickening the 
 researches of scientific enquirers. A working theory is needed in 
 order to give some sort of direction to observation, because without 
 an intelligent idea of what may be the possible fact one certainly will 
 be unlikely to discover the real one. A man who is lost on a dark 
 night, and declines the guidance of a tallow candle because it is too 
 poor a light to illuminate the mountains in the distance, will lose 
 the opportunity of avoiding the holes at his feet. The exploded 
 ideas of Werner served a good purpose in their own day, because the 
 accumulation of observations intended to disprove them became at 
 the same time the basis for other views, which were as much nearer 
 the truth as the data on which they in turn were founded, were 
 more complete and more thorough. During later years the lateral 
 secretion theory of Sandberger became accepted by certain dis- 
 tinguished geologists, and was as vigorously combated by others, 
 notably Posepny, with the result that a great impetus was given to 
 observation, and a large mass of new facts has been collected, 
 bringing the scientific explanations of ore occurrence another step 
 nearer the knowledge of things as they are. The unthinking sneer at 
 the faltering steps of science, and the working miner is apt to belittle 
 the aid which geology gives him. The amount of accurate knowledge 
 of any kind so far attained by the human race is small when com- 
 pared to the bulky mass of that which they think they know, Each 
 
15 
 
 intelligent observation is one step nearer the attainment of truth, 
 and those who direct the working of mines will get more aid from 
 geology when they contribute the necessary data without which the 
 occurrence of ore will remain merely a maze of tangled phenomena. 
 
 It is well to begin a discussion of a subject by defining the terms 
 employed. A " lode " is something that leads a miner, the words 
 " lode " and " lead " having an identical Saxon origin. Australian 
 miners designate a small continuous vein connecting larger ore- 
 bodies as a "leader." "Lode "is therefore a comprehensive term 
 covering many diverse forms of ore occurrence. The word " vein " 
 has a more restricted usage, and describes those lodes in which the 
 ore is supposed to occur in a tabular form, occupying continuous 
 planes which are approximately vertical, and traverse the rocks like 
 interminable sheets of paper set on edge, that is, they are supposed 
 to fill simple fractures made in a perfectly homogeneous material. 
 The term was originally borrowed from the human anatomy, and 
 the oldest writers have used the simile of the rock veined with 
 the precious metal. Nature does not recognise the definitions of 
 the technical dictionary and in mining practice it has been 
 found that regularity of structure is the exception rather than the 
 rule. The geologist of 50 years ago, when the science was more 
 the product of the library and the laboratory than of actual obser- 
 vation underground, conceived the ore as having filled gaping 
 fissures in the rock, comparable to the crevasses of a glacier, and 
 \vhen he had noted the dissimilarity between the ore and the 
 encasing rock, he imagined the former to have been due to an up- 
 vvelling of molten metallic matter. The ideas of the present day 
 are still slightly tainted by the imaginations of the past and the 
 terms of an obsolete philosophy continue to cling to our nomen- 
 clature.* 
 
 Modern investigations, based on accurate chemical knowledge, as 
 .veil as geological observation, have all gone to prove that gold ores are 
 not the product of direct volcanic action, but that they have been 
 con s eyed to the place where the miner finds them through the 
 medium of water, the metals having been dissolved, in various 
 chemical combinations, by underground solutions, and precipitated 
 along those fractures in the rocks which have been first lines of least 
 resistance, and then lines of maximum circulation. The mineral 
 solutions cannot have come from indefinite depths, because the 
 
 * Thus the terms " fissure- vein," ''vein-filling," "vein-walls," &c., carrv 
 with them suggestions which are misleading to untechnical persons, and are 
 the heritage of ideas now, I trust, recognised as untenable in the light of later 
 evidence. 
 
16 
 
 increase of heat (1 F. for every 48 ft. of descent) observable in the 
 sinking of shafts and boreholes indicates that at a horizon of about 
 20,000 ft. below the present surface water would become dissociated* 
 into its constituent gases. It is considered probable, from the 
 evidence yielded by certain classes of lodes, particularly those of 
 nickel ores,t that volcanic action serves to bring the metals from 
 these great depths to that zone of the earth's exterior wherein 
 solvent waters can circulate. The experience of gold mining corro- 
 borates this view, the association of volcanic rocks with bodies of 
 valuable ore having become almost proverbial. 
 
 It is not surprising, therefore, that this very fact has tended to 
 cause a confusion of ideas between volcanic action and lode forma- 
 tion. 
 
 In a railway cutting between the towns of Cripple Creek and 
 Anacoda, there is a bit of nature's testimony which will be of service 
 in getting a clear idea of the essential characteristics of gold-bearing 
 veins as compared with dykes of volcanic rock. The accompanying 
 drawings will help the description. In Fig. 2 there is afforded an 
 excellent illustration of simple dyke structure. The dyke in this 
 case is composed of basalt ; it is from 9 to 15 in. in width, and can 
 be easily traced as an irregular dark band traversing the coarse- 
 grained pink granite. The dyke is very well defined, exhibiting 
 clean-cut lines of demarcation from the enclosing granite, and it is 
 evident from the contour of the walls that it occupies a fault fissure. 
 The outline of the east wall corresponds exactly to that of the 
 western one, the movement of the latter having been upward, 
 causing a displacement equal to about 14 in. It is a clean-cut 
 fissure in the granite, filled with foreign material, a basic volcanic 
 rock, which probably welled upward in a mobile condition, filling 
 the fissure as it was formed, so as at no time to permit of a vacuity. 
 Compare this with Fig. 3, which is a sketch of a gold-bearing vein, 
 situated at a distance of a few yards from the dyke illustrated in 
 Fig. 2. The country is the same, viz., granite, but in this instance 
 the vein filling is not foreign matter, but essentially rock in place ; 
 it is granite, altered, indeed, but easily recognisable, in spite of the 
 kaolinisation of the felspar, and the partial removal of the mica. 
 There are no clearly defined boundaries between the decomposed 
 vein matter and the enclosing country, nor is there any evidence of 
 faulting. The lines of fracture shown in the granite are the joints 
 of that rock, and those which are observable in the vein itself are 
 
 * I refer to the critical point, which is 773 F. At this temperature water 
 cannot, however great the pressure, retain its liquid form. 
 f As indicated by the researches of J. H. L. Yogt. 
 
17 
 
 not continuous, but rather a closely knit series of little breaks, 
 which have afforded a passage for a liquid more subtle than the 
 
 FIG. 2. 
 
 H 'I FOOT 
 
 A*A BASALT V 
 
 GRANITE. 
 
 basalt. The vein occupies a line of maximum porosity along which 
 water, more searching than any molten lava, has found a way, 
 decomposing the soluble ingredients of the rock, and depositing a 
 
18 
 
 minute quantity of gold, insufficient to make the decomposed 
 granite of the vein differ essentially from the outer country, but 
 rendering one gold-bearing ore, and leaving the other barren rock. 
 
 FIG. 3. 
 
 lUt^fbr" 
 
 Here we have a dyke compared with a vein and volcanic agencies 
 brought into strong contrast with aqueous action. The faulting 
 
19 
 
 along the fissure followed by the dyke is easily seen, but no 
 evidences of such movement can be discerned along the seam of 
 altered granite, which forms the gold vein. Nevertheless there 
 must have been some movement, however slight, because a crack 
 or break is not made evident, can be considered only as latent, 
 until the two faces of it are caused, by that very shifting, so to 
 disagree as to produce the irregularities which, when linked together, 
 form the visible line of fracture. Even the joints in the solid granite 
 require such [an explanation, and however insignificant the shifting 
 may be, it marks the adjustment of the rock to the effects of stresses, 
 traceable in this case to the volcanic energies which extruded the 
 large masses of breccia forming the characteristic feature of the 
 geology of Cripple Creek. Permit me to repeat, however insig- 
 nificant this shifting may have been, it made the rocks pervious to 
 underground mineral-bearing solutions, and where it occurred it 
 developed a series of united passages, which afforded a line of maxi- 
 mum porosity, permitting of the circulation of gold-bearing waters, 
 and the subsequent precipitation of the metal dissolved in them. 
 
 The Cripple Creek district exhibits a great variety of vein struc- 
 ture, and in order to afford a general idea of the conditions under 
 which the ore is found it will be necessary to select one or two 
 typical examples. Many of the veins are essentially mineralised 
 dykes, that is, a part, or even occasionally the whole width of the 
 dyke, is sufficiently rich to be regarded as pay ore, and the boun- 
 daries of the dyke then become the walls of the lode. The Moose 
 vein will exemplify this type. The accompanying sketch, Fig. 4, was 
 made at the 350-ft. level. From D to F is the width of the dyke, 
 which in this case is nepheline basalt. It traverses the andesite 
 breccia, which is indicated at AA. The pay ore extends from E to 
 F, a width of 10 in., and it is distinguished from the remainder, 
 EG, comparatively barren portion of the dyke, a dark bluish grey 
 rock, by being iron stained and seamed with reddish brown threads 
 in which gold and tellurides occur. The multiple fracturing, parallel 
 to the walls of the dyke, is a characteristic feature of such lodes, 
 and experience has shown that there is reason to expect the lode to 
 consist of rich ore when it becomes threaded with minute seams 
 following these lines of fracture. This feature can be described as 
 a sheeting of the rock ; it is a very important factor in ore depo- 
 sition. 
 
 Another type is presented by those veins which accompany the 
 phonolite dykes. This is very characteristic of the Cripple Creek 
 district. The direction followed by a majority of the veins, espe- 
 cially on Battle Mountain and Bull Hill, conforms to that of a 
 
 c 2 
 
20 
 
 system of phonolite dykes. While a particular vein may not adhere 
 continuously to the line of the dyke with which it is associated, 
 nor the ore itself be found in the substance of the dyke, when they 
 
 FIG. 4. 
 
 ANDESITE BRECCIA [OfJ NcPHELINE BASALT 
 
 VEIN MATTER 
 
 are together, yet the behaviour of the vein is intimately connected 
 with that of the dyke, and the ore occurrence is modified by both. 
 The accompanying sketch, Fig. 5, recently made in the Independence 
 Mine, will illustrate this. The lode AB is shown to be in breccia, 
 and follows a phonolite dyke, BC, which is 2 ft. wide. The ore is 
 confined to the breccia, and if the phonolite is enriched it is so to a 
 slight extent only, and the enrichment is confined to the planes of 
 
21 
 
 fracture near the lode and does not extend into the body of the dyke. 
 The ore is essentially andesite breccia, rendered gold-bearing by the 
 
 FIG. 5. 
 
 PHONO LITE: 
 
22 
 
 penetration of solutions which have circulated along the line of 
 contact between the phonolite and the breccia. The gold occurs not 
 only in the seams which follow the fracture in the breccia, but it is 
 also found in the heart of it, where a spongy vesicular appearance 
 has been caused by the removal of the more soluble ingredients of 
 the rock. 
 
 In striking contrast to the two types above described I would 
 instance those veins which are neither mineralised dykes nor imme- 
 diately* associated with them, but consist essentially of lines of 
 fracture in the body of the granite itself. A very good illustra- 
 tion is afforded by the Independence vein when it leaves the breccia 
 and extends southward into the granite of the Washington claim. 
 The accompanying drawing, Fig. 6, was made at the bottom of the 
 old whim shaft on the 100-ft. level. The lode is essentially decom- 
 posed granite divided into two equal portions of 2 ft. each on either 
 side of the small seam EF, which consists of a parting, E, marked 
 by a slight clay selvage, and a seam of quartz, F, which is only 
 from J in. to \ in. thick, but very regular and continuous. The 
 lode, which here consists of 4 ft. of 2 oz. ore, has no walls, that is 
 to say, the decomposed gold-bearing granite, CD, is not separated 
 from the undecomposed valueless granite, A and B, by any clearly 
 defined boundary, although the transition from the dark brownish 
 granite into the fresh pink rock can be clearly followed by looking 
 at it from a distance of 5 or 6 ft. The ore is therefore essentially 
 gold-bearing granite, which, if examined, will be found to have 
 undergone several changes, the most notable being the removal of 
 the mica, the decomposition of the felspar, and the addition of 
 secondary quartz ; the general effect being to give it a honeycombed 
 spongy character. 
 
 The lode above described is similar to the outcrop which so many 
 overlooked in 1890 and 1891, because it carried no visible metallic 
 minerals or free quartz. It will be of interest to examine the 
 famous outcrop more closely. The reef has evidently undergone a 
 weathering, yet it has withstood the elements, because it carries 
 more quartz than the surrounding rock. The outcrop ceases to 
 appear at a point now occupied by the No. 1 shaft of the Inde- 
 pendence Mine. This shaft is situated at the contact of the granite 
 and the breccia. The lode continues northward for a great distance, 
 as the subterranean workings testify. Southward the lode is 
 encased in granite, and it is itself composed of granite. The barren 
 outer rock is pink in colour, and its constituent minerals present a 
 
 * Emphasis is laid on " immediately " because the Independence vein, for a 
 large part of its known course, accompanies a phonolite dyke. 
 
23 
 
 fresh unaltered appearance. The gold-bearing portion, comprised 
 within the lode, has a dull brown tinge ; it is noticeable that the 
 mica is absent, having evidently been leached out, leaving patches 
 of chlorite and iron-stained spots in which free gold can occasionally 
 
 FIG. 6. 
 
 
 .- 4 : 4 . 
 
 '. --. 4- + . 
 -K ..+ 
 
 * 
 
 t t 
 
 + 
 -T44 
 
 -,% - V\ ' ^/- '..".*.. / -4- T 
 
 . 4-4 + + - 
 
 4- ./ + .4- + + + + 
 
 N. v f ..4 +- 4- 4 
 
 4. 4- 4 -4. -4 '. : :. . js+- : tf '..-. v 1 - , ' 
 
 4. -4- -i -4 1-. -+-'. **><1" ' ' ' 1 f. '.-\ '4 ' * '. 
 4 4- 4 -4 4- . /.-/: vT'. *.- '.. t T -. 
 
 v^li^S 1^?! ? ifr^vv. 
 
 ^^IKf Itifell w^ 
 
 4 4 4 4 - ' - V. V ' *-"A.flX / ' ' V' ' -.-I- ' f- 4- t t - 1 
 444 4\'. + v- . V --'I ' - ' V >^- '^ 4 <- 4 4 4 -h 
 
 :*>.-*.-*.Vrv>> + .->sH-:.J. ::/:t :^ :: .-j>^ + 4 + ^ 
 
 4444 *. " T V X''-'l ' ' ' J.' l! >>^ ....* 4 + 1 
 
 4 4 -+ 4\'..>V +.. X X't' ...'. ' V-f .-x^'. '. ^>- + - 4. H +4* 
 
 +^ -*+'.*i: x 4 v*/ + .i'--'-'\i>- +" '.% 4 + 4 4 
 
 ^vJ-^ f Mf;v^^; .>y 
 
 4. 4 4-4 *'+.. f x IA. % ./' f- -I .-> f 4 -f- >- 
 
 .4 4. ^ 4 . - - ;:W - . . ; fl*,/v> ' ;' :<<* * * t T ^ 
 
 ^ 4 \"V^-i : V : -i'. *-'''-ii"''[ - ^. * i^ 1 ~4. w^ 
 
 AC *F "h * >i1t 
 
 OR 
 
 LODE 
 
24 
 
 be distinguished ; of the two felspars* of the original rock the more 
 soluble has become kaolinised, while the other remains so undecom- 
 posed as to preserve much of the usual appearance of the granite ; 
 the original quartz has been removed, probably by the action of the 
 hydrofluoric acid, the presence of which at one time is strongly 
 suggested by the purple fluorite now staining portions of the ore ; 
 further, there is abundant secondary quartz, in groups of opalescent, 
 indistinct crystals, to the presence of which the lode owes the fact 
 that it is harder than the enclosing granite. 
 
 When the lode penetrates the breccia it continues to be made up, 
 not of free quartz or any other foreign vein-matter, but of the 
 formation which it traverses, so that south of the contact the Inde- 
 pendence is essentially gold-bearing granite, and north of the contact 
 it is gold-bearing andesite breccia. Why there is no outcrop north 
 of the contact I do not know, unless it be that the lode partakes of 
 the fissile and easily eroded character of the breccia, and has not 
 been strengthened by the infiltration of sufficient additional secondary 
 quartz to enable it to withstand the obliterating hand of time. 
 
 The character of this lode presents several notable features, a high 
 value from a commercial standpoint coinciding with peculiar 
 scientific interest. At the third level there is presented a good idea 
 of the general relation existing between the gold-bearing portion, 
 recognised as " the lode," and the rock formations which it traverses. 
 It is remarkable that while the several bands of gold-bearing matter 
 have a general parallelism and sympathy with the course of the 
 two phonolite dykes, yet a large part of the ore is not contiguous to 
 the phonolite, but traverses the granite and the breccia, regardless 
 of such structural features as the contact or the dykes themselves. 
 The ore has no defined walls ; when definite partings appear to 
 limit the widths of gold-bearing material it is only to mislead ; there 
 are similar " walls " both within the ore itself and beyond it in the 
 outer country. When the ore abuts against a phonolite dyke it 
 does not usually extend into the dyke, save occasionally where 
 tellurides are found upon the cleavage planes of the latter near 
 its edges. Where the lode crosses the contact the ore changes at 
 once from gold-bearing granite to gold-bearing breccia. A widen- 
 ing of the ore-body exists at the contact, and for a considerable 
 distance both north and south of it. The composition of the rocks 
 appears to have been an entirely unimportant factor as compared to 
 the physical and structural conditions in the locality of the ore 
 deposit. The evidence warrants the most careful study, and would 
 
 * Orthoclase and oligoclase. The plagioclase variety, containing a larger 
 percentage of lime, is the one which has undergone decomposition. 
 
25 
 
 furnish the text for a long discussion of the essential features of ore 
 deposition. Few examples of lode structure so well emphasise the 
 general truth of those modern ideas of ore deposition which are 
 advocated by the teachings of Posepny. It is interesting to 
 accentuate this fact, because there was an erroneous impression 
 conveyed, in the early days of Cripple Creek, by the writers of the 
 daily press, that the gold-field set at naught the accepted teachings 
 of geological science. The idea was due to the careless utterances 
 of local men, and never emanated from any recognised authorities. 
 The converse is true, and should be emphasised, namely, no modern 
 mining region so clearly establishes that explanation of ore deposi- 
 tion, which is based upon the recognition of the laws governing the 
 circulation of underground waters, under conditions traceable to the 
 geological structure of the rocks. 
 
 THE ORES AND MINERALS. 
 
 In discussing the geological features of the district, frequent 
 emphasis has been laid upon the fact, that the ore is usually only 
 rock, whether granite, phonolite, or breccia, which has become im- 
 pregnated with gold-bearing minerals to a slight extent as regards 
 percentage, but to a notable degree as regards commercial value. 
 In 1893, when W. S. Stratton, the owner of the Independence, sent 
 several carloads of rich ore from his mine to the Denver smelters, 
 the officials at the works thought a blunder had been made and 
 that loads of ballast had been inadvertently consigned to them. 
 The ore was obviously granite and it required a* trained eye, such 
 as that of Dr. Richard Pearce, manager of the Boston and Colorado 
 Smelting Company, to detect the fact that the mica of the granite 
 had been largely removed, leaving small, iron-stained spots amid 
 which there were disseminated dull yellow specks of gold. A 
 glance into the ore-bins of the chlorination establishments will 
 exhibit a mixture of broken rock, which looks more like the spoil 
 of a barren cross-cut than the yield of a rich stope. The petro- 
 grapher, in looking over this material, could easily label the rock, 
 and if not initiated, he would wonder whether it could be gold- 
 bearing. On being assured that it was valuable as such, he would 
 take a few pieces, and break them open so as to examine a fresh 
 surface, and it would not be long before he would see on the planes 
 of fracture, evidences of richness. 
 
 The gold occurs either in the native condition or as a telluride, 
 and is found distributed among the interstices of the rock, lining 
 the fractures or penetrating the substance of it in threads of vary- 
 
26 
 
 ing minuteness. In lodes traversing the granite, the gold, or the 
 tellurides containing it, will be scattered amid the porous cavities 
 due to the removal of certain more soluble portions of the rock ; 
 in phonolite, the values will be found more frequently along 
 fractures than in the heart of it. This renders the last mentioned 
 class of ore very difficult of estimation. In the andesite breccia, 
 the component fragments of which are so heterogeneous, the physi- 
 cal character of the rock varies considerably, and the gold values 
 will partake of an irregular sporadic distribution. 
 
 The distinguishing feature of the ores of the district, is the 
 occurrence of tellurides. The discoveries of these uncommon 
 minerals, produced nearly as many misconceptions a few years ago 
 as the finding of similar minerals at Kalgoorlie in West Australia 
 Tellurides seemed to create as much confusion among the miners of 
 both countries, and to be as puzzling as the finding of the Ornith- 
 orhyncus paradoxus (or duckbilled Platypus) to the naturalists at 
 the beginning of this century. Colorado, however, was better 
 prepared for the telluride discoveries of Cripple Creek, than 
 Australia was to exploit those of Kalgoorlie. The latter were 
 unprecedented, the former only followed the line of previous, partly 
 forgotten, experiences in the Boulder and La Plata districts of the 
 same State. 
 
 A few general notes concerning the composition of these com- 
 plex ores will be of interest. And first a few definitions are 
 necessary. The " tellurides " are compounds of tellurium with 
 certain metals, and they are so termed just as the compounds of 
 sulphur are called " sulphides " ; thus, for example, calaverite is 
 the telluride of gold, while iron pyrites is the sulphide of iron. 
 The name " tellurium " is derived from the Latin tellus, meaning 
 the earth, and was chosen in opposition to that of the element 
 selenium, which comes from the Greek word, selene, the moon. 
 Tellurium is a non-metallic element with a metallic lustre, it acts 
 as an acid base, just as selenium and sulphur : the three forming a 
 recognized chemical group having common affinities. If tellurium 
 were a metal, as is often supposed, its combination with gold or 
 silver would only be possible as an alloy. 
 
 It is usually assumed that the precious metals enter into the 
 composition of tellurides, and a high commercial value is taken for 
 granted in speaking of this species of minerals. Nevertheless, 
 there are many varieties which are valueless to the gold miner, such 
 as the telluride of mercury, called Coloradoite, which occurs at 
 Kalgoorlie, as well as at Magnolia in Boulder County, Colorado ; 
 there are also the telluride of bismuth, called Tetradymite, and the 
 
27 
 
 telluride of lead, called Altaite, and the telluride of nickel, 
 Melonite, all of them found occasionally in the mines of Boulder 
 Comity, as well as in the ancient mining region of Transylvania, 
 where most of them were first recognised. These tellurides of the 
 baser metals occur, for the most part, in quantities so restricted as 
 to have no commercial value and are rather to be considered as 
 curiosities much desired by the mineral collector. 
 
 In the mining camps it is a frequent custom to speak of tellurium 
 when it is intended to refer not to that element, but to its com- 
 pounds with gold or silver. Tellurium itself occurs native, that 
 is, in a free state, just as gold, silver or copper. It is tin-white in 
 colour, it is soft but brittle, and is usually found in a granular 
 massive condition. A commercial value of $3*50 per ounce is ordi- 
 narily quoted for tellurium, but the demand for this rare earth (as 
 the chemist terms it) is very slight, and a few shipments of it would 
 quickly demoralize the market. No native tellurium has yet been 
 found in the Cripple Creek district, but in Boulder County, 90 
 miles further north, it occurs among gold ores in a free state, and a 
 mass weighing 25 Ib. was found in the John Jay Mine about twenty 
 years ago. 
 
 Certain telluride materials very much resemble the common ores 
 of silver, the sulphide of silver (called argentite), for example, is 
 difficult to distinguish from hessite, the telluride of the same metal, 
 silver. The instance is quoted in order to refer to a simple test 
 applicable to any doubtful cases. Remove a small bit of the sus- 
 pected mineral with the point of an old knife, and put it in a porce- 
 lain dish or a white saucer. Add three or four drops of strong sul- 
 phuric acid, and heat over a lamp. Should tellurium enter into the 
 composition of the suspected mineral, a beautiful purple will suffuse 
 the colourless acid. The miner's time-honoured test is to put the 
 ore in the fire of a blacksmith's forge and roast it. Tellurium fuses 
 at a comparatively low temperature, and becomes volatilised, passing 
 off in white fumes of telluric oxide. If the telluride mineral con- 
 tains gold, the latter will remain in the form of globules. Even 
 the precious telluride hidden in the seams of the piece of ore will be 
 exuded as a yellow perspiration. The miner calls this process 
 " sweating," and the reason for it becomes obvious when the results 
 are observed. 
 
 Experienced miners, such as those of the Boulder district of 
 Colorado, who have been working amid these particular ores for 
 twenty-five years, know very well, from the disappointing returns 
 of many a shipment to the smelter, that there are several minerals 
 closely resembling tellurides which are not rich in gold, and there- 
 
28 
 
 fore that a rough test, by roasting, is occasionally necessary. The 
 mineral may go off in fumes when heated, leaving no gold or silver 
 behind, as native tellurium does. Consequently, the Boulder miners 
 are apt to call everything native tellurium which in the process of 
 roasting disappears entirely or leaves a residue in which the precious 
 metals are not recognisable. But among the latter would be in- 
 cluded the tellurides of lead, bismuth, and nickel ; and to the former 
 belongs not native tellurium alone, but also the telluride of mercury, 
 because mercury also readily volatilises under the conditions of the 
 roasting test. This mistake was made at Kalgoorlie, where I found 
 the telluride of mercury being labelled " black tellurium," for the 
 reason just referred to. The mineral combination of tellurium and 
 mercury is rare ; it was first found at the Mountain Lion mine at 
 Magnolia, in Boulder County, and a simple test for it is to roast a 
 particle of it in a glass tube. The mercury is volatilised at the hot 
 lower end of the tube, and is condensed at the cool upper end in the 
 form of minute metallic globules, which are readily recognisable as 
 quicksilver. 
 
 The principal telluride minerals found in the Cripple Creek ores 
 are sylvanite, calaverite, and petzite. Sylvanite, named after the 
 place of its discovery, the historic goldfield of Transylvania, is the 
 most characteristic of Cripple Creek ores, very beautiful specimens 
 of it having been obtained at, among others, the Independence, 
 Portland, Moon, Anchor, and Anchoria-L eland Mines. It is a double 
 telluride, containing gold and silver, an average composition being 
 28 per cent, gold, 16 per cent, silver, and 56 per cent, tellurium. 
 Sylvanite is a brilliant silvery -white mineral, having a characteristic 
 crystalline habit, to which it owes its other name, " graphic tellu- 
 rium," the arrangement of the crystals resembling Arabic lettering. 
 On account of the large percentage of gold in the composition of 
 the richest ores of Cripple Creek, it has been concluded that the 
 prevalent mineral is not a silver-bearing telluride, but that the gold 
 occurs combined with tellurium alone in the form of the mineral 
 calaverite. Calaverite is the simple telluride of gold, pure speci- 
 mens contain 44*5 per cent, gold and 55*5 per cent, tellurium. It 
 is named after the county of Calaveras, in California, where it was 
 first found at the Stanislaus Mine. It usually carries from 2 to 3 
 per cent, of silver, which must then be considered as an impurity. 
 The purest varieties have a bronze-yellow colour. It is the charac- 
 teristic mineral of the rich ores of Kalgoorlie, and beautiful speci- 
 mens of it are common in the Great Boulder, Associated, and Lake 
 View Mines of that celebrated district. Calaverite is rather difficult 
 to distinguish from iron pyrites ; the difference in colour is slight, 
 
29 
 
 but the former is easily cut by a knife, while the latter will not 
 permit of it. The cubic crystalline habit of pyrites will usually 
 help to make it known, because calaverite rarely occurs in any other 
 than a massive form. The best specimens obtained in the Cripple 
 Creek district came from the Work Mine. 
 
 Reference has been made to the uncertainty as to the identity of 
 the particular telluride mineral which carries the values in many of 
 the Cripple Creek ores. It is very probable that future investiga- 
 tions will discover the existence of a new variety, peculiar to the 
 district, in which many of the physical characteristics of sylvanite 
 will be united to a composition so rich in gold as to resemble 
 calaverite. 
 
 Petzite, named after the German chemist Petz, is, like sylvanite, 
 a double telluride of gold and silver, its average composition being 
 25 per cent, gold, 42 per cent, silver, and 33 per cent, tellurium. 
 It is much darker than sylvanite, being steel-grey to iron-black ; it 
 is also slightly harder and more brittle. The best specimens of 
 petzite found in the district came from the Geneva claim on Gold 
 Hill, about four years ago. Recently the writer found petzite in 
 the ore of the Porter Gold King Mine 
 
 All these tellurides are distinguished from the baser minerals, with 
 which they may be occasionally confounded, by their rich lustre. 
 
 The lodes of Cripple Creek are further characterised by the 
 presence of fluorite or fluorspar (the fluoride of calcium), a beautiful 
 purple mineral, which is so notably associated with the ores of the 
 district as to have led to the idea that it could be accepted as an 
 indication of the richness of the veins in which it was found. But, 
 like most similar attempts at short cuts to knowledge of this kind, 
 the generalisation has proved fallacious. There are several large 
 lodes of very low grade ore in the district which are purple with 
 fluorite, and there are some very rich ores almost devoid of it. 
 The association of the gold and the fluorspar points to a similarity, 
 and possibly a contemporaneity, of origin ; but this fact does not, 
 and could not, predicate whether the quantity of gold present will 
 give the ore an average value of $2 or of $200 per ton. As a 
 matter of science, both kinds of ore may be considered gold-bearing, 
 as a matter of business, one spells losses and the other dividends. 
 
 In the upper levels of the mines, within the reach of surface 
 waters, the tellurides are decomposed and the gold has been 
 liberated. In the first years of development, certain mines, such as 
 the Pike's Peak and Garfield Grouse, on Bull Hill, afforded speci- 
 mens of native gold, the dull brown lustreless appearance of which 
 was a puzzling variation. At Kalgoorlie, likewise, a brittle spongy 
 
30 
 
 variety became known as " mustard gold." In each instance, when 
 such a specimen is scratched with a knife or burnished, the bright 
 gleam of pure gold is made apparent. These varieties of native 
 gold are directly traceable to their origin from tellurides, which 
 have been decomposed by oxidation, the gold often retaining the 
 form of the original mineral, and being a perfect skeleton of u 
 former mode of occurrence. Beautiful pseudomorphs, as they are 
 called, of gold after sylvanite,* are common in the ores of Cripple 
 Creek. 
 
 Below the depth, which ranges from 100 to 400 ft., reached by 
 surface waters, the unaltered tellurides appear in all their un- 
 tarnished beauty. At a further depth, from 500 to 700 ft., the ores 
 become more complex, because of the increasing percentage of baser 
 minerals, chiefly iron pyrites, but including also galena (the sulphide 
 of lead) and stibnite (the sulphide of antimony). This change is 
 important chiefly from a metallurgical standpoint, because the 
 increase of "sulphur renders the roasting of the ores more expensive. 
 The general question of the probable changes to be encountered as 
 the mines become deeper will be discussed under another heading, 
 at the close of this description of the district. 
 
 THE TREATMENT OF THE ORES. 
 
 Most of the gold of commerce has been won from simple ores, 
 those in which the precious metal occurs in a native condition 
 encased in quartz. Stamp-milling, accompanied by amalgamation, 
 is the process ordinarily employed to reduce them. Another type, 
 of greater importance every year, is represented by the ores in 
 which the gold occurs intimately associated with iron pyrites, but 
 so minutely disseminated as to be rarely visible even under the 
 microscope, and therefore inviting the supposition that it is chemic- 
 ally combined in a condition as yet not understood. A modified 
 form of stamp-milling is employed for some of these ores, but for 
 the most part they afford a field for great diversity of practice, 
 including chemical and smelting processes of many kinds. The 
 third type of gold mining, and in many respects it is the most 
 modern, is represented by ores in which the gold is known to be 
 chemically combined in definite proportions with the element 
 tellurium. Several mining regions produce these telluride ores. 
 Transylvania in Europe, Colorado in the United States, and West 
 
 * At tlie Gold Xing Mine, in Poverty Gulch, I recently secured specimens 
 carrying crystals of gold pseudomorphic after krennerite, a mineral resembling 
 calaverite, but occurring in prismatic crystals. 
 
31 
 
 Australia in the Antipodes are the principal localities. Transyl- 
 vania has an interest which is chiefly historic, but Cripple Creek in 
 Colorado, and Kalgoorlie in West Australia, are writing their 
 names in glittering figures on the records of the present. The new 
 phases of metallurgical practice inaugurated by these recent dis- 
 coveries of telluride ores have given a great impetus to this technical 
 science, the aid of which is now thoroughly appreciated by the 
 miner and the capitalist alike. 
 
 The changes which have occurred since 1891 in the treatment of 
 the ores produced by the mines of Cripple Creek are a fitting 
 illustration of the fact that the development of metallurgical prac- 
 tice, like all true progress, is a slow evolution from simple begin- 
 nings to a full fruition. It is a common fallacy to suppose that 
 processes of ore treatment are unexpectedly discovered by rumi- 
 nating chemists or revealed from on high to the millman, and fre- 
 quent paragraphs go the round of an ill-informed press to the effect 
 that this or that spectacled professor has lit on a new combination 
 in physics or chemistry which is to revolutionise the existing 
 methods of ore reduction by extracting 100 per cent, at a negligible 
 cost. The progress of metallurgical practice resembles organic 
 evolution in that it does not advance per saltum. The chlorination 
 process was first applied, in 1857, by Deetkin, in California. It 
 took a quarter of a century of patient endeavour to place it on a 
 safe commercial basis. MacArthur and Forrest's application of 
 potassium cyanide was used, at the Crown Mine in New Zealand, 
 as early as 1889, but the chemical reactions which occur in the 
 cyanide process are still incompletely understood to-day, and the 
 development of this method of ore treatment cannot be said to have 
 ceased. 
 
 The first ore broken at Cripple Creek was carried on the backs of 
 prospectors to Colorado Springs or Florissant, and forwarded to the 
 smelters of Pueblo and Denver. Such small shipments of selected 
 ore usually mark the birth of our western mining districts. Subse- 
 quently larger lots in wagons were similarly consigned, but the 
 costs were high and the proportion of ore capable of yielding a 
 profit under such conditions was small. The miner felt the neces- 
 sity of extracting the gold by milling it nearer the place whence it 
 came. He fell back on his previous experience in other localities 
 and put up a stamp-mill. 
 
 The stamp-mills were built on the model of those of Gilpin 
 County, the oldest gold mining district in Colorado, and therefore 
 had light stamps, 400 to 500 Ib. ; a slow drop, 30 to 35 per minute ; 
 a long drop, 17 to 20 in. ; and a deep discharge, 12 to 15 in. The 
 
32 
 
 ore was broken by hammers and fed by hand into the batteries, 
 except in the case of the Rosebud mill, which was provided with 
 rock-breakers and automatic feeders. Amalgamation, on copper 
 plates, both inside and outside of the mortars, followed the stamp- 
 ing. During the three years succeeding the first discoveries the 
 following plants were at work : 
 
 Name of mill. 
 
 Locality. 
 
 Date of 
 erection. 
 
 No. of 
 stamps. 
 
 Lawrence 
 
 
 1892 
 
 20 
 
 Summit 
 
 Gillett 
 
 1892 
 
 30 
 
 Gold and Globe 
 
 Cripple Creek 
 
 1892 
 
 40 
 
 Beaver Park . 
 
 Beaver Park 
 
 1893 
 
 20 
 
 Colorado Springs 
 
 Beaver Park 
 
 1893 
 
 25 
 
 
 
 1893 
 
 20 
 
 Hartzell . . 
 
 
 1893 
 
 20 
 
 Gold Geiser 
 
 
 1892 
 
 15 
 
 
 
 1893 
 
 20 
 
 Rosebud 
 
 Mound Citv 
 
 1893 
 
 60 
 
 
 
 
 
 The total is no less than 270 stamps. In April, 1897, only 50 
 out of this number were dropping, and to-day they are all idle, 
 having been replaced by large leaching plants shortly to be de- 
 scribed. 
 
 The first ores came of course from the surface, or near it, and 
 were therefore oxidised. The gold occurred in a free state, having 
 been liberated from its combination as a telluride. This last fact 
 was not known and not appreciated even when first it became 
 known. It affected the milling most seriously, because gold having 
 this origin is coated with a film of the tellurite of iron, which is a 
 serious obstacle to amalgamation. The extraction in the stamp- 
 mills was soon found to be low, and attempts were made to remedy 
 the incompleteness of the treatment by employing bumping tables 
 and Frue vanners to arrest the gold escaping amid the tailings. 
 When this failed, blankets were added, and these in time became a 
 recognised addition to the mills. Even then the best extraction 
 barely reached 50 per cent, of the gold in the ore, as shown by 
 assays, and a great deal of good ore was wasted in an ineffectual 
 effort to win a profit. The usual rate for treatment was $3 per ton, 
 delivered at the mill. 
 
 Early in the development of the district there came men who 
 recognized the unsuitability of stamp milling for the treatment of 
 telluride ores, and in 1893, W. S. Morse, of the Russell Lixiviation 
 Works, at Aspen, made the experiments which formed a basis for 
 
33 
 
 the erection of a chlorination plant built by Edward Holden, at 
 Lawrence, 2 miles from the town of Cripple Creek, at the close 
 of the same year, 1893. Holden purchased an old stamp-mill at 
 Lawrence and altered it to a chlorination plant which, although it 
 was crude and incomplete, successfully demonstrated the suitability 
 of the process employed. This was barrel chlorination on the 
 model of the practice of South Carolina and Dakota. The erection 
 of the first well-designed plant, using this process, was begun at 
 Gillett, in August, 1894, and completed in the following January. 
 This had a capacity of 50 tons per day. 
 
 The eyanide process had been already tried, with results not 
 wholly satisfactory, because of the variable composition of the ores 
 and the inexperience of the men who organised the first milling 
 enterprise. The local company, controlling the MacArthur-Forrest 
 patents, built a cyanide mill of 40 tons capacity, at Brodie, in 1892. 
 It was* remodelled in 1894. In 1895 the Metallic Extraction Com- 
 pany's mill was built near Florence. It has been enlarged from 
 time to time and now has a capacity of 8,000 tons per month. The 
 cyanide process made less progress than barrel chlorination, so that 
 while two mills now employ this method, six use the other. The 
 Colorado-Philadelphia chlorination mill was built at Colorado city 
 in 1896. It has a capacity of 6,000 tons per month. The El Paso 
 mill, with a capacity of 3,000 per month was built at Florence in 
 1897. The Gillett mill doubled its capacity in 1898. Others were 
 erected as shown on the accompanying list. 
 
 The Mills of the Cripple Creek District. 
 
 Name. 
 
 Locality. 
 
 Date of 
 erection. 
 
 Capacity 
 per day. 
 
 Ch farina Ho n 
 
 Cripple Creek 
 
 1893 
 
 tons. 
 30 
 
 Gillett 
 
 Gillett 
 
 1894 
 
 80 
 
 Colorado-Philadelphia . . 
 
 Colorado City 
 
 1896 
 
 200 
 
 El Paso 
 
 Florence 
 
 1897 
 
 100 
 
 Colorado 
 
 Arequa . 
 
 1897 
 
 75 
 
 
 Florence . . ... 
 
 1897 
 
 50 
 
 Cyanidation 
 Brodie 
 
 Cripple Creek 
 
 1892 
 
 60 
 
 Metallic Extraction .... 
 
 
 1895 
 
 270 
 
 Page 
 
 Florence . . ... 
 
 1896 
 
 20 
 
 
 
 
 
 The Lawrence mill was burnt down in 1896, and the owners of 
 it built the El Paso, at Florence, immediately afterwards. The 
 
 d 
 
34 
 
 Page mill was erected to use a secret modification of the cyanide 
 process, but after a brief activity it became idle. 
 
 The trend of events indicates that the future growth of the 
 milling practice will favour an increase in the chlorination mills 
 rather than in cyanide establishments. At first, cyanidation was 
 conducted upon raw ores, but this gave good results only when they 
 were oxidised. Koasting is now considered a necessary preliminary 
 and it has removed the advantage which in the earlier years of the 
 district cyanidation possessed over chlorination, a process always 
 preceded by the roasting of the material subjected to it. 
 
 The chlorination practice of the district has undergone no radical 
 changes during recent years. It is typical barrel chlorination. In 
 the matter of the recovery of the gold from solution there is a 
 difference, the Gillett mill, for instance, using charcoal as a pre- 
 cipitant, while the Colorado-Philadelphia plant uses sulphuretted 
 hydrogen. The mills at Florence enjoy an important advantage 
 in the use of oil residuum, instead of coal, in their roasting furnaces. 
 The residuum comes from the distillation of petroleum and costs 
 about 1 dollar per barrel now, although a few years ago the price 
 was much less. There is an increased demand for it because it 
 affords a fuel peculiarly adapted for roasting, permitting of a nice 
 and quick adjustment of the temperature of the furnace. 
 
 During recent years the metallurgical practice in the chlorination 
 plants has remained fairly constant, the improvements being in the 
 direction of large capacity and better mechanical arrangements 
 rather than in any changes in the chemical department. 
 
 The cost of treatment at one of the larger mills, having a 
 capacity of 3,000 tons per month, is, per ton of ore treated : 
 
 Labour and salaries $1*20 
 
 Chemicals and supplies 078 
 
 Fuel 0-65 
 
 Wear and tear 0'55 
 
 Incidentals .. 0*28 
 
 $3-46 
 
 Add to this interest on investment, general expenses and depre- 
 ciation of plant, and the total costs will approximate $4 '00 per ton. 
 The above figures are based on chloride of lime costing $2 '40, and 
 sulphuric acid $1*25 per 100 Ib. Koasting alone costs from 45 to 
 60 cents per ton. This item has grown as the mines have become 
 deeper, the sulphur contents having increased from an average of 
 1 per cent, in 1895 to 2J per cent, at the present time. The im- 
 
35 
 
 provements in other departments of the milling have more than 
 balanced this change. 
 
 The ores are altered phonolite, andesite breccia or granite, and 
 therefore have a composition similar to these rocks save in an in- 
 creased prcentage of quartz. A representative analysis may be 
 quoted as 
 
 Alumina 29'94 
 
 Silica 63-13 
 
 Lime 0'70 
 
 Iron oxide 3*66 
 
 Iron sulphide 2'64 
 
 Magnesia trace 
 
 Manganese oxide O40 
 
 Sulphur 0-96 
 
 Two interesting features of Colorado practice have been brought 
 out by the treatment of the Cripple Creek ores, the first being the 
 greater use of mechanical roasters, such as the Pearce, Ropp, and 
 other furnaces, and, secondly, a modification of the methods em- 
 ployed to sample the ores. The material produced by the mines is, 
 as compared with the typical ores of other districts, high grade and 
 very variable in its gold contents. This variability is due to its 
 mode of occurrence as a telluride in minute seams irregularly 
 scattered, and, of course, extremely rich, rendering it difficult to 
 apply the law of averages and obtain a satisfactory sample of a 
 large lot of ore. In its passage from the hands of the miner to 
 those of the smelter, the ore usually goes through the sampling 
 works, the owner of which may be considered a broker whose 
 business it is to see that both parties in the transaction get those 
 values in the ore which one sells and the other buys. It was soon 
 found that Cripple Creek ores were most unsatisfactory to sample, 
 the results being unreliable and erratic. This became remedied in 
 process of time by crushing a larger part of any particular lot of 
 ore and taking pains to pulverize the final pulp sent to the assay er 
 to 100 mesh,* instead of 60- or 80-mesh. It has also been found 
 that, on account of the variability of the ore, it is good business 
 for the mine owner to let all his product pass through the sampler 
 on its way to the smelter, and this has led to the erection of half a 
 dozen sampling works in the Cripple Creek district. The usual 
 cost of sampling is 75 cents per ton. 
 
 That is, 10,000 holes per square inch. 
 
 d 2 
 
36 
 
 THE MINES. 
 
 Cripple Creek is interesting to the geologist ; it is fascinating to 
 the financier. When viewed from the latter standpoint it presents 
 many aspects which render it unique among modern gold mining dis- 
 tricts. The mines of Cripple Creek have paid their own way from 
 grass roots, that is to say, they have not grown up by the expendi- 
 ture of working capital in development. Working muscle has made 
 a 10-ft. hole into a productive mine. There is, therefore, an in- 
 stant contrast between the financial features of the industry when 
 compared with the goldfields of the Transvaal or West Australia. 
 
 It may be objected that all mines are first made by the pick of 
 the miner and are then enlarged into important enterprises by the 
 investment of capital in machinery and development. Nevertheless 
 the contrast above suggested is not a strained one, because it is 
 a fact that the mines of Kalgoorlie and Johannesburg were merely 
 tracts of land when they became the basis for large company flota- 
 tions. The shafts were sunk afterwards by the companies organised 
 in London, or elsewhere, and the ore was uncovered by workings 
 which had no existence at the time of the first organisation of the 
 enterprise. Companies were brought out with a large subscribed 
 capital, a portion of which was paid out in the purchase of property 
 and another portion was set aside as a working capital, that is, 
 a fund out of which to pay the expenses of equipment and that 
 amount of development necessary to enable the mine to maintain a 
 steady production. It is rarely the case that a mine floated on the 
 London market is able to pay the increased dividends necessitated 
 by an increased capitalisation without some preliminary vigorous 
 development such as will permit of an enlarged output without 
 exhausting the ore reserves. In the case of the deep-level mines of 
 the Eand, the working capital is a princely sum, sufficient to sink a 
 shaft a couple of thousand feet, or even more, and erect a mill of 
 two or three hundred stamps. The finances of South African 
 mining are a study apart and the result of conditions previously 
 unknown in gold mining, although paralleled in the coal industry. 
 It represents a wonderful development of modern practice, such as 
 renders the digging for gold a steady business very much unlike the 
 feverish uncertainties of the days of 1851 in California and 
 Australia. 
 
 Even in districts which have not the extensive low.grade deposits 
 of the Eand, it is necessary to provide for a rainy day, and English 
 capitalists are accustomed to the idea of furnishing a certain amount 
 of money as a reserve fund to tide over the lean places in a mine's 
 
37 
 
 development. The practice is a good one, and to a great extent 
 offsets the large capitalisation of most British incorporations. The 
 American buys his mine and proceeds to work it for all it is worth, 
 the dividends are pocketed, and when the rich ore is exhausted 
 there comes a collapse. The shares of American companies are 
 usually non-assessable; the shareholders, who receive the divi- 
 dends, will often refuse to contribute fresh capital, and the mine 
 may be closed down until, after an interval, some one with a good 
 deal of pluck re-opens it. But this is rare. As a consequence 
 many properties which made a magnificent record are now idle, and 
 this idleness means, not inactivity alone, but the rusting of the 
 machinery and the falling in of the workings, rendering it a very 
 costly matter to re-open the mine. The English practice of heavy 
 capitalisation has been censured often enough, but there is this to 
 be said for the methods of London investors, that by subscribing an 
 adequate working capital they often permit the mine manager to 
 enlarge the capabilities of a property so as to enable it to hold up 
 cheerfully under its increased load and continue exploratory work 
 during those intervals when the production does not meet the 
 operating expenses. 
 
 Our ways of notation in Colorado are much more simple, and this 
 very simplicity would ruin any but the best of mines. A mining 
 claim is in the possession of three or four working miners, who 
 secured it originally by location. It does not pay its way, although 
 there is evidence that it is worthy of development. They go to a 
 couple of merchants in the nearest town, and each of these pays the 
 wages of one working miner to represent him. The prospect hole 
 becomes a shaft, and a little good ore is discovered. A company is 
 organised by a lawyer or a stockbroker. The capitalisation will be 
 a million shares of a nominal value of a dollar, but a rating of 10 
 or 20 cents per share. The owners give 10 per cent, of the stock to 
 the incorporator. Work is resumed with the aid of the money 
 obtained by selling a small block of shares. If the mine does not 
 pay, it is leased or some stock is sold. At the best it is a hand-to- 
 mouth policy, which succeeds in spite of its weak points, because of 
 the richness of the mine. 
 
 In other cases the original working miner is bought out for a few 
 hundred dollars, and the new owners go ahead subscribing the 
 money required to meet expenses, month by month, until the 
 patience of one or more is exhausted, and either the impatient 
 minority sells to the plucky majority or the entire party gives up 
 the fight for riches, and awaits a buyer who may happen along at a 
 time when the camp is excited by new discoveries on neighbouring 
 claims. 
 
38 
 
 The history of Cripple Creek, however, records comparatively 
 few abandonments, because the veins have proved so generally pro- 
 ductive that their yield has sufficed to keep the work of development 
 going ahead, even if it did not meet all the expenses. As soon as a 
 small mine becomes organised into a company, it is listed on the 
 stock exchanges of Denver and Colorado Springs as a " prospect," 
 and when it becomes a regular producer it is promoted to the 
 society of " mines," the two classes being kept distinct on the call- 
 lists of the exchanges. 
 
 A mine which does not pay goes through eras of greater or less 
 activity, according as the owners of it can scrape together the 
 money needed to continue the work. Idleness is possible because the 
 mining regulations do not entail forfeiture on that account. The 
 claim can be " patented," that is to say, the owner obtains a title in 
 fee simple from the U.S. Government when he has done a certain 
 amount of work, nominally rated equal to the expenditure of |500, 
 and the Government surveyor has prepared the map needed for 
 record in the bureau of the surveyor-general. Labour conditions 
 such as obtain in the English colonies are unknown in Colorado, and 
 the continuous operation of a mine cannot therefore be enforced 
 under the mining laws. 
 
 This is itself an important feature of mining in this State, and it 
 will appeal at once to those who have been shareholders of Aus- 
 tralian mining companies. I remember, when at Coolgardie in 
 1897, what a serious matter the labour conditions were to the West 
 Australian companies which had acquired an extensive acreage 
 during boom times, and were compelled to work a large force of 
 men during a period of financial stringency. The regulations 
 required the working of claims on which no ore had been found on 
 pain of forfeiture, and, therefore, enforced the expenditure of money 
 regardless of the nature of the work to be done. This clause in the 
 mining law, which compels the working of a certain number of men 
 on each claim, known in Australia as the " labour covenants," has 
 its good features, the chief being that it prevents good mining 
 claims from remaining undeveloped by those who, from choice or 
 necessity, would like to pursue a dog-in-the-manger policy. In a 
 lively mining district, like Cripple Creek, it is not needed, and 
 would only impose irritating obligations, but in the older camps of 
 the United States it has led to the severance from the public domain 
 of large areas, which remain unexplored on account of the poverty 
 or want of energy of absentee owners, who will not exploit the 
 mines, and refuse to sell them save at prohibitive prices. It must 
 be remembered that an idle mine is only a hole in the ground, and 
 
39 
 
 there is nothing more worthless. The problem is a far reaching 
 one, and is only mentioned incidentally because it is still agitating 
 the mining departments of the colonial governments. 
 
 The leasing system is still an important factor in Cripple Creek 
 mining. Three or four years ago it was more prevalent. The 
 owners of claims who were too poor to develop them, or too timid, 
 cut them up into several sub-divisions and leased them. The lessees 
 might be working miners, who engaged the service of others under 
 them, or the mine might be leased to outside parties, who hired 
 workmen in the ordinary way. The period of the leases varied 
 from six months to two years, and the royalties were 15 to 20 per 
 cent, of the net returns, that is, the receipts from the mill or 
 smelter, after the costs of transport and treatment are deducted. 
 Leasing is the last resort of the perplexed mine-owner, and is a 
 confession of inability to work one's property, yet in the early days, 
 because the mines were so often owned by men wholly unfamiliar 
 with mining, the system served a good purpose, and many rich 
 mines owe their first beginnings to the enterprise of a lessee. 
 
 The history of the mines is a pleasant one, encouraging to those 
 who have been led by the experience of other districts to consider 
 mining only as a reckless gamble in which blind luck outweighs 
 intelligence. The infrequent transfer of mines, which has charac- 
 terised the story of Cripple Creek up to the present, is due to the fact 
 that the conditions for successful mining are present to an unusual 
 degree. In the first place no deep sinking was needed to reach the 
 ore. Although outcrops were rare, and discovery was thus delayed, 
 it soon became evident that the tops of the ore-bearing veins 
 could be reached by trenching. The hills became spotted with 
 yellow heaps of rock, and it looked in 1894 and 1895 as if they had 
 been invaded by gophers of a larger growth. Ore was encountered 
 at depths of from 10 to 30 ft. It was rich. Cripple Creek has 
 always been a high grade camp ; the average yield for several years 
 exceeded 3 oz. per ton, and last year, notwithstanding an enormous 
 increase in the low grade milling ore, it was fully 2 oz. Therefore, 
 even in the earliest period of development, the ore could meet the 
 costs of transport to the smelters. But competing lines of railroad 
 were soon pushed into the district, and facilities for cheap mining 
 were obtained long before the goldfield had reached a quarter of its 
 present importance. This fact permitted poor men to work the 
 mines, because it gave them a market for their ores ; muscle and 
 energy were sufficient, capital was not needed to the extent known 
 in less favoured localities. Even to this day no single mine has a 
 reduction plant of its own ; it is not needed. As the camp grew, 
 
40 
 
 the chlorination and cyanide mills erected in or near the district 
 began to compete with the smelters, and prevented the latter from 
 levying excessive rates of treatment ; and, lastly, the demoralisation 
 of the silver market already referred to earlier in this description 
 as having occurred at the time of the closing of the Indian mints in 
 1893, which put a severe check on what was then the chief industry 
 of Colorado, did at the same time aid Cripple Creek immensely by 
 diverting the energies of a very resourceful population to the 
 development of the mines of its newly discovered goldfield. 
 
 STATISTICS. 
 
 From the first beginnings in 1859 to the close of 1898 Colorado 
 has produced 
 
 Gold 9,512,242 oz. $196,618,054 
 
 Silver 362,526,541 326,482,532 
 
 Lead 1,064,762 tons 87,131,457 
 
 Copper 43,089 10,742,167 
 
 The production for 1898 is estimated to have been 
 
 Proportion of 
 U.8. output. 
 
 Gold 1,138,584 oz. $23,534,531 34 per cent. 
 
 Silver 23,502,601 13,690,265 38 
 
 Lead 56,708 tons 4,117,043 26 
 
 Copper 5,435 1,304,504 2 
 
 At the present time the mineral production of the State, inclu- 
 sive of coal and iron, has a value of $55,000,000 per annum. 
 
 There are 30,000 men employed in the mines of Colorado out of 
 a total population of 520,000. 
 
 The smelting industry of Colorado has been an all-important 
 factor in the growth of its mining districts. There are ten large 
 smelting works in the State (at Denver, Pueblo, Leadville, and 
 Durango), and several smaller plants whose activity is intermittent. 
 The value of the entire product of the smelters amounted in 1898 
 to $61,000,000. This included the product from ores which came 
 from neighbouring States and from British Columbia. 
 
 At the present time 3,500 tons are smelted daily in Colorado. 
 The annual tonnage consists of 900,000 tons of ore, 300,000 tons of 
 iron flux, and 185,000 tons of limestone, the balance of the lime 
 needed being obtained in the form of ores, which carry more of 
 it than is required for their own treatment. Aspen provides the 
 bulk of the latter material. 
 
41 
 
 The charges for. treatment depend upon the composition of the 
 ore, particularly the ratio of iron to that of silica. On a neutral 
 basis the charge is $4*25 for oxidised ores and $7 per ton for 
 sulphide ores. On highly silicious ores, containing 60 to 70 per 
 cent, silica, the charge is 8 per ton, flat. 819 per oz. is paid for 
 the gold in ores carrying up to 2 oz. per ton, and 19'50 per oz. for 
 those which are richer. 
 
 Until 1892 silver mining was the most important industry ; since 
 that year gold mining has been in the ascendant. The production 
 of gold has grown steadily and rapidly, as the following figures 
 testify : 
 
 1892 256,410 oz. $5,539,000 
 
 1893 364,151 ,, 7,527,000 
 
 1894 462,009 9,549,730 
 
 1895 656,021 13,559,954 
 
 1896 738,618 15,267,234 
 
 1897 947,249 19,579,637 
 
 1898 1,138,584,, 23,534,53x 
 
 This increase is to be credited chiefly to the development of 
 Cripple Creek, the gain from that district having been the largest 
 part of the improvement made by the State in its entirety. The 
 output of the Cripple Creek district has been : 
 
 1891 100 oz. $2,060 
 
 1892 2,821 583,010 
 
 1893 104,000 2,150,000 
 
 1894 140,710 2,908,702 
 
 1895 332,800 6,879,137 
 
 1896 363,400 7,512,911 
 
 1897 490,500 10,139,708 
 
 1898 653,410 13,507,349 
 
 The analysis of the figures of the last three years exhibits the 
 growth in the tonnage of ores treated by the chlorination and 
 cyanide mills as compared with the smelters : 
 
 Smelting ore. Milling ore. 
 
 Tons. Value. Tons. Value. 
 
 1896 84,659 6,045,319 77,388 $1,467,592 
 
 1897 94,287 5,697,788 181,885 4,441,920 
 
 1898 110,036 7,137,366 251,862 6,369,983 
 
 The smelters charge a minimum rate of $6*50* on Cripple Creek 
 
 * Smelter rates have gone up since this was written, pending the readjust- 
 ment of the ore market, recently deranged by a labour strike which compelled 
 several of the works to be inactive for three months. 
 
42 
 
 ores, the mine owner paying the cost of transport by rail, which 
 item varies from $3 to $5 according to the richness of the ore. 
 
 The chlorination and cyanide plants have the following scale of 
 charges : 
 
 $7 per ton on ores carrying up to \ oz. per ton. 
 
 7 |O ,, ,, \ 55 
 
 8-50 1 
 
 Q 1 1 
 
 " 11 11 L ^ 55 
 
 10 1J 
 
 10-50 2 
 
 Ores carrying more than 2 oz. per ton are subject to smelter 
 rates. The mills pay $20 per ounce for the gold. In the above 
 charges is included the cost of transport, varying from 90 cents to 
 $1*50 per ton, which is met by the mill owners. Thus on a 2-oz. 
 ore the smelter charge would be $6 -50 plus the freight. $4, making 
 $10-50, this being equal to the milling rate, plus transport, on the 
 same ore. The consequence is that ores carrying less than 2 oz. go 
 to the mills and the richer stuff to the smelters. 
 
 The dividends declared by the mines ,of Cripple Creek during 
 1898 amounted to $2,596,144, but to this figure must be added the 
 profit made by mines not owned by public companies and also that 
 of the numerous leasing parties, bringing the total dividends to 
 fully $3,000,000. 
 
 Out of the 121 American mines quoted as dividend payers on the 
 list of the New York Stock Exchange, 38 are in Colorado, and 23 
 are situated in the Cripple Creek district. A few of the principal 
 ones among the latter are quoted below, together with the details of 
 their production. 
 
 Independence . . . 
 Portland 
 
 Depth area. Production in 1898. 
 
 -T.. . Total 
 
 D ^ vl -. 1 dividends 
 dends in , ~ , , 
 IQQC j to Oct. 1, 
 1899. 
 
 Feet. 
 
 Acres Tons. 
 
 Value. 
 
 Per 
 ton. 
 
 920 
 
 903 
 735 
 680 
 643 
 518 
 1000 
 820 
 650 
 620 
 
 I 
 
 112 8,378 
 183 27,798 
 100 13,548 
 (150) 31,512 
 14 8,252 
 30 17,] 83 
 11 34,775 
 40 22,342 
 103 19,329 
 n 9,957 
 
 $ 
 
 459,57(5 
 1,^79,681 
 565.279 
 1 ,051,149 
 352,329 
 536,265 
 952,134 
 415,863 
 576,538 
 453,987 
 
 $ 
 54-85 
 67-62 
 41 72 
 33-33 
 42-67 
 31 -21 
 30-28 
 18-61 
 29-83 
 45-59 
 
 S j S 
 220,949 3,062,164 
 570,000 2,377,080 
 None. ! 472,500 
 130,000 240,000 
 ] 35,000 261,000 
 220,000 686,960 
 350,000 i 1,555,000 
 45,000 228,500 
 126,875 253,750 
 142,140 256,610 
 
 Isabella 
 G-old Coin 
 Moon- Anchor . . . 
 Elkton 
 Victor 
 
 Golden Cycle .... 
 Vindicator 
 
 Lillie 
 
 
43 
 
 Some additional notes concerning a few of the big 'mines will not 
 be out of place. The Independence is one of the pioneer mines of the 
 district. It was pegged out by W. S. Stratton on the 4th of July, 
 1891, and remained under his sole ownership until May 1st, 1899, 
 when he transferred it to an English company, incorporated under the 
 name of Stratton's Independence, Limited. This great mine has never 
 yet been pushed to its full capacity for production. In 1895 eight men, 
 while engaged in purely development work, broke ore which netted 
 an average of $155,000 per month for seven months in succession. 
 Of the total area covered by the property, not one quarter has as 
 yet been explored. Up to May 1st, 1899, the mine had produced 
 44,224 tons, having a gross value of 84,071,860 and yielding a 
 profit of 82,574,164. During the first quarter of the new company 
 there were produced 9,222 tons, having an average gold content of 
 4'02 oz., and a total gross value of 8708,106. A dividend of 
 < 100,000 was distributed on account of operations from May 1st to 
 July 31st. The ore reserves already opened up ensure a continuance 
 of this rate of production for many years. 
 
 The Portland adjoins the Independence on the north. Of its 
 entire acreage only a little over 8 per cent, has been as yet explored. 
 During 1898 the total receipts were $1,890,641, while the expendi- 
 ture was $881,833, and the resulting profit $1,008,808. Dividends 
 to the amount of 8570,000 were distributed, and additional claims 
 were acquired. The surplus carried forward was 8668,000. At the 
 present time dividends at the rate of 24 per cent, are being paid on 
 the share capital of 83,000,000. The total production of this mine 
 to the end of 1898 has been 109,591 tons, having a value of 
 86,427,523. The average per ton is 858-65. There have been 
 expended on permanent equipment 8228,213, and on purchase of 
 adjoining claims 8619,953. Nevertheless the total dividends have 
 already been $2,377,080, and there is reason to believe that the mine 
 is yet young, and destined to do bigger things. 
 
 The Isabella became famous early in 1899 on account of extra- 
 ordinarily rich discoveries which permitted of a resumption of 
 quarterly dividends. Three separate shipments of over 50 tons 
 each averaged 45 oz. of gold per ton. This ore was obtained 20 ft. 
 above the ninth level, and the news of it caused a wild speculation 
 in the shares of the Company. 
 
 Xext door to the Isabella is the Victor Mine, which is said to 
 have been bought in 1893 for 852,000 by Messrs. Moffat and Smith, 
 who still control its operations. The dividends paid since then 
 have an aggregate value 22 times the purchase price of six years 
 ago. The profit earned in 1898 was $323,724. The total output 
 
44 
 
 to the end of that year has been 12,242 tons of smelting ore and 
 82,249 tons of milling ore, having a total value of $2,161,186. 
 
 Regarding other mines above mentioned, it remains but to add 
 that most of them have made much larger profits than the dividends 
 indicate, the want of reserve capital causing the expenditure of part 
 of the profits for the acquisition of adjoining territory or the carry- 
 ing forward of a surplus to be used as necessity arises. 
 
 FUTURE PROSPECTS. 
 
 In the eighth year of its existence Cripple Creek produced 13 J 
 millions, of which 22 per cent, was distributed in the form of 
 dividends. Is this to be the height of achievement ? It is less 
 difficult to foretell the career of a young man than the future of a 
 mere child. Cripple Creek has grown to full manhood, having 
 passed safely through the ills of its adolescence, and has developed 
 a distinct character of such stability that one is justified in prophesy- 
 ing a career of increasing success. 
 
 The present boundaries of the productive portion of the district 
 are approximately identical with the area occupied by the andesite 
 breccia, and the other rocks of the volcanic complex. This covers 
 about ten square miles. It is undoubtedly the proper territory for 
 further exploration, and no part of it offers greater promise than 
 the line of contact separating the breccia from the granite. Never- 
 theless the geological conditions outside this circumscribed area are 
 such as to forbid hasty conclusions discouraging to prospecting in 
 the granite, which surrounds the district on all sides. 
 
 The recent discoveries of pay-ore in Grassy Gulch, and on Copper 
 Mountain are suggestive of the probable extension of the boundaries 
 of the goldfield. It is known that the phonolite dykes which are 
 associated with the productive lodes of the central area extend into 
 the outer granite. Indeed several rich mines are wholly in the 
 granite, at distance varying from a few hundred feet to over 2,000 
 feet from the breccia. The Strong and Gold Coin are notable 
 examples, while among those most distant from the main mass of 
 the breccia may be mentioned the Orizaba and Prince Albert on 
 Beacon Mountain, and the Sweet and Caledonia, west of Anaconda. 
 It must not be thought that these mines exhibit an ore occurrence 
 wholly distinct from the main volcanic complex ; such an idea 
 would be unwarranted, because, while they are situated far outside 
 the mass of andesite breccia, the gold-bearing lodes, which they 
 develop, are associated with phonolite, in dykes and masses. The 
 geology of Beacon Hill is especially characterised by a very large 
 intrusion of that rock. 
 
45 
 
 It is not extraordinary that the vicinity of the contact of the 
 granite with the breccia should be a favourable environment for 
 large bodies of ore. The contact must have been, at all times, first 
 a line of weakness, next a line of movement and consequent fractur- 
 ing, and finally a line of water circulation. Thus there existed 
 the conditions which experience and observation indicate as being 
 most favourable to mineralisation, especially when to these is added 
 the penetration, across the contact, of bodies of volcanic rock, 
 such as the dykes of andesite, basalt, and phonolite. Although 
 comparatively little ore has been found lying immediately upon the 
 contact, there is plenty of proof, in the Independence, Portland, 
 and Granite Mines, for example, of the fact that the lodes crossing 
 it have been beneficiated. Similarly the phonolite dykes, when 
 they pass out into the granite, have afforded a line of weakness 
 along which fracturing has subsequently occurred, forming shattered 
 planes and lines of maximum porosity permitting of the circula- 
 tion of the underground solutions which precipitated the precious 
 metal. Every added page of evidence only further confirms the 
 view, held by the writer early in the infancy of the camp, that 
 Cripple Creek corroborates to a striking degree the most modern 
 explanations of ore deposition chiefly associated with the name of 
 Posepny. 
 
 What of the deep 1 Will increasing depth be accompanied by 
 impoverishment 1 This is not asked with the timidity of a few 
 years ago when the lodes had only been followed two or three 
 hundred feet in vertical descent, and it was foreseen that they 
 would eventually cut into the granite under the breccia. At that 
 time the future of the district was uncertain, and many cautious 
 men held back in fear of unfavourable developments. It is obvious 
 that the mines near the edge of the depression occupied by the 
 breccia, will penetrate into granite by sinking their shafts or by 
 extending their levels, as illustrated in the accompanying sketch, 
 Fig. 7. This has occurred notably in the case of the Independence 
 and Portland Mines, which reach the granite on the southern and 
 western sides of the territory owned by them. It is very satis- 
 factory to l)e able to record the fact, that magnificient ore-bodies 
 have been found in these two properties upon veins which have 
 been followed downward into the underlying granite. Nor should 
 this be surprising in view of the discoveries made during recent 
 years in the granite south and west of the contact with the breccia. 
 If good ore is found in the granite at a horizontal distance of 2,000 
 ft. from the mass of breccia, why should it not be also found 
 at a similar vertical distance below the same formation 1 All the 
 
46 
 
 evidence to hand goes to show that wherever the dykes have 
 broken through the rocks of the volcanic complex, they have per- 
 mitted of ore deposition, and that therefore the possibilities of 
 
 FIG. 7. 
 
 * * , * * - ' r < o x " # ''X^ %^ 
 
 gVV) GRANITE (V3 BRE 
 
 CCIA 
 
 future discovery are not limited to the present restricted known 
 productive area. 
 
 If the mines of the district were old, deep, worked out, one would 
 
47 
 
 be timid of foretelling a continued and advancing yield of gold, 
 because the brutal facts of experience do not countenance the popu- 
 lar idea of increasing richness with depth ; but the mines of Cripple 
 Creek are young, comparatively shallow, and only fractionally 
 explored; each month's development, whether in a lateral or a 
 vertical direction, uncovers ore reserves previously unsuspected, 
 save by those to whom painstaking observation has given a clue. 
 
 There is every probability that the near future will see the intro- 
 duction of capital from the outside, because the production of the 
 district has attracted the attention of the larger financial centres. 
 Nor is this anything but desirable. If the sale of the mines meant 
 the retirement of the present owners, their withdrawal from mining 
 operations and the transfer of the properties to absentee capitalists, 
 the benefits of the change might well be questioned ; but it is a 
 fact that those who control the best mines also own several smaller 
 undeveloped claims, and the result of a sale of any of the big pro- 
 perties would mean the liberating of large sums of money to be 
 used for the opening up of promising young mines, which now are 
 either idle or incompletely explored. The mining men of Colorado 
 have been bred in the atmosphere of gold-seeking, and the acquire- 
 ment of riches usually only leads to larger operations. It is 
 unnecessary to cite examples. They are a part of local history. 
 
 If the growing reputation of the district should thus lead to the 
 investment of large sums of money, the immediate result would be 
 greatly to augment activity in exploratory work, and in the wake 
 of this greater development there will come, inevitably, discoveries 
 of an importance eclipsing those, the yield of which is the basis of 
 the present productiveness. 
 
 The steady betterment in economic conditions tends continually 
 to decrease the working costs and to make a commensurate addition 
 to the tonnage of ore available for exploitation. This is the story 
 of all modern mining regions. The Rand illustrates it ; Kalgoorlie 
 accentuates it. There is no immediate probability of any radical 
 change in methods of ore reduction or transport, but there is a 
 tendency in several directions to diminish the expense of handling 
 low grade ores. Two railroads tap the district, and the competition 
 prevents rates of transport being unduly high. The building of a 
 third line is probable, should the production of the camp increase 
 as it promises. Electric haulage is likely to become a factor in 
 reducing this item of expenditure. The increased capacity of the 
 mills, due to their steady enlargement and the better arrangement 
 of the machinery, is permitting them to buy ores which at one time 
 were considered to have no commercial value. Thus five years ago 
 
48 
 
 the minimum rate for freight and treatment was $12 per ton, while 
 to-day it is $7 per ton. During the same period the smelter rates 
 of treatment have dropped from $15 to $6*50 per ton. What a 
 reduction such as this means, and how great a tonnage of low grade 
 material it transfers from the category of rock to ore, will be 
 appreciated by those who have watched the growth of other 
 districts. 
 
 The writer has seen the development of more than one of the 
 great goldfields of the globe, and looking back upon the brief history 
 of that development, he recognises that those which have pi oved 
 permanent, share certain characteristics in common. In the general 
 persistence of the ore bodies, in the size and continuity of the lode 
 channels, and in the economic conditions favouring an easy realisa- 
 tion of the values contained in the ores, Cripple Creek exhibits the 
 features of a great goldfield, and affords the promise of a future 
 which will eclipse the achievement of the first eight years of its 
 existence. 
 
 HAEEISOK AND SONS, Printers in Ordinary to Her Majesty, St. Martin's Lane. 
 
SUBJECT TO BEVISION-. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Cripple Creek Volcano. 
 
 BY T. A. RICKARD, STATE GEOLOGIST OF COLORADO, DENVER, COLO. 
 
 (Washington Meeting, February, 1900.) 
 
 THE Cripple Creek district occupies a cluster of foot-hills on 
 the south side of Pike's Peak and is a portion of an extensive, 
 though uneven, plateau which unites the eastern range of the 
 Rocky mountains with the Sangre de Cristo. It is essentially 
 a small volcanic area, of about 20 square miles, amid the granite 
 of the Front range. But though, when regarded as a rich 
 mining district, it may be considered as an isolated area,* yet, 
 geologically, it is, as Whitman Cross has pointed out, only an 
 outlying portion of a much larger volcanic region, whichf 
 stretches to the south and west, around Silver Cliff and the 
 Rosita hills, forming the picturesque country cut by the deep 
 canons of the Arkansas river and its tributaries. 
 
 The mines are situated amid a volcanic complex, consisting 
 of tuffs and breccias which have been penetrated by an exten- 
 sive system of dikes and other intrusive masses. The prevail- 
 ing formation is an andesite breccia, which lies upon the worn 
 surface of the granite and fills the deep basin around a volcanic 
 vent. The breccia, since its deposition, has been broken into 
 by several eruptions of phonolite and, later still, by a series of 
 thin dikes of basalt and other allied rocks of a highly basic 
 composition. 
 
 The successive sedimentary formations which, elsewhere in 
 Colorado, lie upon the basal granite, are not represented in the 
 district; whatever sediments were laid down before the volcanic 
 period must have been removed by erosion, and there is very 
 little evidence which affords a datum-line whereby the geolog- 
 ical age of the volcanic eruptions can be determined. Whit- 
 
 * The main mining belt of Colorado is 30 or 40 miles to the west, and extends 
 through Boulder, Gilpin and Summit counties, into Leadville, and then south- 
 westward, through Aspen, into the San Juan region. 
 
 f " Geology of the Rosita Hills, Custer County, Colo.," by Whitman Cross. 
 Proceedings of the Colorado Scientific Society, vol. iii., 1890. 
 
2 THE CRIPPLE CREEK VOLCANO. 
 
 man Cross has referred the breccia* of Cripple Creek to the 
 close of the Eocene period or to the early Miocene, f This is 
 done by correlating the small deposit of grit which occurs on 
 Straub mountain, and is the only sedimentary formation in the 
 district, with the lake-beds at Florissant, 15 miles to the north. 
 These celebrated fossil-beds belong to the late Eocene ; they 
 are largely made up of volcanic dust and are covered by breccia 
 similar to that of Cripple Creek. Moreover, they are overlain 
 by rhyolite identical in character with that which forms the 
 floor of the gravel-deposit on Straub mountain. 
 
 The granite which forms the basal rock of the region is 
 usually described as Archean. It is probably Algonkian. It 
 is, elsewhere, overlain by Upper Cambrian strata ; and it has 
 been found to include fragments of quartzite which are be- 
 lieved to be of pre-Cambrian or Algonkian age. Therefore 
 the granite is not necessarily Archean, but, to quote Dr. 
 Cross, " older than the only Cambrian rocks as yet identified 
 in Colorado."! 
 
 "Within the Cripple Creek area the granite differs in appear- 
 ance from the rock which generally prevails in the Pike's 
 Peak region. It is a well denned reddish biotite (black mica) 
 granite, and, instead of the microcline (feldspar) which ordi- 
 narily characterizes the Pike's Peak formation, it carries ortho- 
 clase in prominent tabular crystals. The quartz is usually 
 
 * The miners call the breccia "porphyry." This term is derived from the 
 Greek word "porphyra," meaning purple. It was first applied to the beautiful 
 dark-red rock which the Romans obtained from the quarries of Ghebel Dokhan, 
 near the shores of the Eed Sea. This original "porphyry " would now be classed 
 as a porphyrite. However, the original name, which depended upon color, has 
 long since lost its force in another meaning, which refers to the structure. The 
 original "porphyry," according to Zirkel, was speckled with snow-white and 
 rose- red crystals of feldspar in a blood- red ground- mass. Hence the term became 
 applied to rocks in which some particular mineral, frequently feldspar or quartz, 
 stands out well defined from the general matrix, giving it a spotted look, as for 
 example in the familiar " bird's-eye porphyry" of the western miner. The term 
 is often employed as though it covered a particular species of rock, while in fact 
 it is merely a descriptive adjective-noun, covering any kind of crystalline rock 
 having a mottled appearance due to the predominant development of one of its 
 constituent minerals in individual crystals. 
 
 f " Geology and Mining Industries of the Cripple Creek District, Colorado," 
 by Whitman Cross and R. A. F. Penrose, Jr., IMA Ann. Rep. U. S. Geol. Sur., 
 Part II, p. 18, 1895. The writer owes a great deal of his descriptive geology to 
 this valuable monograph. Op. tit., p. 17. 
 
 % I obtained some fine twin crystals (Carlsbad type), 2 inches long, from the 
 top of Bull Hill. 
 
THE CRIPPLE CREEK VOLCANO. 3 
 
 iron-stained, and the mica shows the commencement of a 
 change into green chlorite. The oligoclase, which occurs as a 
 subordinate feldspar, shows a ready tendency to decomposition, 
 especially near the ore-bodies in the mines. 
 
 Turning to the examination of the breccia,* we find that it 
 consists of a consolidated mass of fragmentary material having 
 a coarseness comparable to gravel. Occasionally the pieces 
 are as large as a man's hand ; but these are rare. More fre- 
 quently the breccia is very fine, and then comes under the 
 designation of " tuff." It is mainly composed of augite-andesite, 
 in which smoky-brown prismatic crystals of apatite occur. 
 The feldspar is kaolinized, and the dark silicates, such as augite 
 or biotite, have undergone destruction by leaching. While the 
 mass of this formation is made up of andesite, it exhibits, 
 locally, a good deal of fragmental phonolite and granite, the 
 latter more particularly in the vicinity of the contact. Fine 
 pyrite is distinguishable in most specimens. In the upper 
 workings of the mines the kaolinization of the feldspar has 
 given the rock a bleached appearance ; and at the surface the 
 iron oxides, derived from the alterations of the pyrite, have 
 stained it yellow or red. Fluorite is a frequent constituent, 
 wherever the breccia is penetrated by the gold-bearing veins, 
 and colors it a dark purple. The finer tuffs are often so silicified 
 as to be undistinguishable, except under the microscope, from 
 massive rocks. The decomposed breccia also exhibits the 
 healing effects due to the infiltration of secondary quartz ; and, 
 when it is included within the boundaries of any of the ore- 
 deposits, the soluble ingredients have been removed to such an 
 extent as to leave often only a pumice-like remnant of inter- 
 lacing quartz. 
 
 Penetrating the mass of the breccia and extending into the 
 surrounding granite, there is an intricate series of dikes, chiefly 
 of phonolite. f This is usually a light-colored rock of even 
 
 * "Breccia" and "tuff" are both words of Italian origin. We owe many 
 terms describing volcanic materials to the study of Vesuvius. " Breccia " means 
 "broken." It is applied to rocks made up of a consolidation of angular frag- 
 ments. "Tuff" is employed both for a rock built up of fragmental material of 
 smaller size than that composing a "breccia," and also for the rock resulting from 
 the mud caused by the action of water upon volcanic dust. In the latter sense, 
 the original Italian word " tufa " is made use of by many authorities. 
 
 f "Phonolite " is derived from the Greek words " phone," sound, and "lithos," 
 stone. The close texture and even grain of the phonolite causes it to give a ring- 
 
4 THE CRIPPLE CREEK VOLCANO. 
 
 texture and sherd-like fracture ; but the conditions of its occur- 
 rence, in thin and in thick dikes, in almost horizontal sheets, 
 and in shapeless intrusive cores, are so varied as to have in- 
 duced a great many modifications in its physical characteristics. 
 The essential constituents are sanidine (the glassy variety of 
 orthoclase) and nepheline. The crystals of the latter are occa- 
 sionally sufficiently developed to give the rock a porphyritic 
 appearance. Besides the normal phonolite there are allied 
 rocks, such as trachytic* phonolite and nepheline-syenite,f oc- 
 curring under various structural conditions. There are also 
 dikes of andesite,J similar in character to the earlier rock 
 which, in its fragmental form, composes the bulk of the breccia. 
 Finally, crossing these rocks, and therefore last in the sequence 
 of eruption, are the dikes of nepheline-basalt with which im- 
 portant ore-bodies are associated on Eaven hill and Battle 
 mountain. 
 
 The Cripple Creek district represents the ground-floor of a 
 volcano, the superstructure of which has been removed by 
 erosion. Let us consider what this means. Among the gains 
 of modern science there is none more striking than the elucida- 
 tion of the causes which bring about the terrifying phenomena 
 of volcanic action. A hundred years ago, an active volcano 
 excited superstitious fear, and was regarded only as a catas- 
 trophic interruption to the order of nature. Since then, the 
 patient researches of sucK men as Spallanzani, Scrope and Judd 
 have enabled us to recognize in these activities the orderly 
 operations of forces subject to definite laws. 
 
 ing sound when struck with a hammer. In England it is often called "clink- 
 
 stone. 
 
 * " Trachyte " is from the Greek word meaning " rough." The rock usually 
 has an uneven fracture, due to the angular sanidine and the porosity of the ground- 
 mass. 
 
 t "Syenite" comes from the Greek Syene, the town in Egypt now known as 
 Assouan. It is a curious fact that it has, comparatively recently, been found that 
 the rock at Assouan is not a typical syenite, which is a variety of granite contain- 
 ing very little quartz, with hornblende replacing the mica. It is really a red 
 granite, very much resembling that of Pike's Peak. The Egyptians quarried it 
 for their obelisks, and out of it they built the Temple of the Sphinx at Ghiseh. 
 
 J "Andesite" is derived from Andes, the mountain range in South America 
 where it is particularly prevalent. 
 
 $ The word "volcano " is Italian. It was the name given to one of the Lipari 
 Islands in the Mediterranean, where quiet eruptive action has been going on since 
 the tinie of the ancients, who considered the little mountain-island as the forge of 
 the Roman god Vulcan. 
 
THE CRIPPLE CREEK VOLCANO. 5 
 
 The scope of scientific investigation has included not only the 
 observation of existing* volcanic action, but also the examination 
 of the remains of extinct volcanoes. The structure of the latter 
 has thrown light on the behavior of the former. As the story 
 of the development of forms of life now extinct, but preserved 
 in fossil-beds and recorded for us by the palaeontologist, ad- 
 vanced our insight into the structure of living things, while 
 biology repaid the aid thus received from palaeontology by con- 
 tributing the clues through which the incomplete evidence of 
 the rocks was so correlated as to demonstrate the sequence of 
 strata, so the study of the volcanoes of to-day led geologists to 
 recognize the results of similar action in masses of rock, the 
 eruptive origin of which was previously unsuspected, and, in 
 turn, the deciphering of the skeletons of extinct volcanoes ad- 
 vanced the understanding of those which have survived. Nat- 
 ural sections gave the requisite testimony. Atmospheric ero- 
 sion, acting through vast periods of time, has cut into the 
 mass of many of the ancient volcanoes of the earth so as to un- 
 cover their anatomy. The dissection, by Professor Judd, of 
 the old volcano of Mull,f in the Western Isles of Scotland, is 
 an excellent example of this method of research. Occasionally 
 mine-workings, or excavations made for other purposes, afford 
 valuable evidence as to the internal structure of volcanic moun- 
 tains. The Eammerbuhl, in Bohemia, is a curious instance. J 
 It is a small hill, apparently of no particular interest, but, 
 nevertheless, it was once the subject of a hot scientific discus- 
 sion. The poet Goethe took part in the dispute, and persuaded 
 a friend, Count Sternberg, to drive a tunnel into the hill with a 
 view to settling the question of its origin. The result justified 
 Goethe's claim that it was " a pocket edition of a volcano.'' 
 It was found that the hill consisted of a mass of volcanic scoria, 
 through the center of which passed a plug of basalt. The plug 
 obviously occupied the choked-up vent of the volcano, from 
 which proceeded a lava-stream which had flowed over the flank 
 of the hill. Fig 1 illustrates this statement. 
 
 * There are about 350 active volcanic vents on the surface of the earth at the 
 present time. 
 
 f Quarterly Journal of the Geological Society, vol. rxx. , p. 220, etc. 
 
 t See Judd's "Volcanoes," pp. 112-114. 
 
 \ "Scoria " is a Latin word, unchanged. It is used especially for coarsely ve- 
 sicular lava, but often for fragmental lava in general. 
 
THE CRIPPLE CREEK VOLCANO. 
 
 n. < 
 O"' 
 
THE CRIPPLE CREEK VOLCANO. 7 
 
 At Cripple Creek, the mine-workings afford a good deal of 
 information concerning the underground structure of the region. 
 It is hoped that an inquiry into the history of the volcano 
 which determined the interesting character of the district will 
 contribute towards a clearer comprehension of the geology of 
 the mines. 
 
 The operations of nature in the past are inferred from the 
 observation of those which take place to-day. The intensity may 
 vary; the forces are the same. This is the corner-stone of 
 modern geology as laid down by Lyell. The volcanic complex 
 at Cripple Creek is to be understood in the light of the evidence 
 gathered for us by the patient investigators who have stood by 
 the side of the craters of Stromboli, Vesuvius and Kilauea. 
 
 The conclusions of those who have made a specialty of this 
 branch of geology* may be summarized thus : The explosive 
 violence of volcanic eruptions is due to the access of water to 
 the fused rock within the conduit of the volcano ; but, as it ap- 
 pears that this water is not contained within the substancef 
 of the lavaj emitted during the tranquil emissions succeeding 
 the first paroxysmal outburst, it is inferred that the water is not 
 the primary cause of volcanic action, which originates at a depth 
 greater than that to which it is believed that water can pene- 
 trate. The evidence collected is not complete ; but it warrants 
 a reasonable conjecture that volcanoes owe their origin to the 
 contraction, caused by the cooling, of the earth's crust upon a 
 yielding substratum, separating the solid outermost shell from 
 an equally solid nucleus. || While, therefore, the force which 
 
 * Among the best literature on the subject may be mentioned Volcanos by 
 Poulett-Scrope, Volcanoes by Judd, and Characteristics of Volcanoes by Dana. 
 
 f That is, " occluded." 
 
 J Lava is Italian for "stream." It is from the same Latin root as lave, lava- 
 tory, etc. Although the term is usually applied to the fused material emitted by 
 a volcano, it is often employed in referring to the same rock after it has become 
 consolidated, especially when the rock has not been specifically classified. 
 
 \ ' ' Secular refrigeration .' ' 
 
 || The question of the condition of the earth's interior is too large for extended 
 reference. Besides the standard text-books on geology, the reader will find much 
 suggestive matter in Osmond Fisher's "Physics of the Earth's Crust," and in 
 Prestwich's " Controverted Questions of Geology." There is also a summary of 
 the evidence regarding this subject in the address of Sir William Thompson 
 (Lord Kelvin) before the meeting of the British Association in 1876. The gen- 
 eral conclusions of science have been lately expressed, in a popular way, by Pro- 
 
8 THE CRIPPLE CREEK VOLCANO. 
 
 pushes large quantities of fused rock to the exterior of the earth 
 has, probably, a deep-seated origin, nevertheless, the imme- 
 diate cause of the uncertainty, the violence and the magnificent 
 energy of volcanic action is traceable to the effects produced by 
 water coming into contact with the lava as it approaches the 
 surface. 
 
 The destructive energy of a volcano may be likened to a 
 boiler-explosion ; volcanoes may be considered the safety-valves 
 of creation. The mass of incandescent rock which is slowly 
 being squeezed upward meets a large volume of water which 
 flashes into steam with a sudden expansion causing the most 
 astounding results. One cubic foot of water yields 1700 cubic 
 feet of steam. It is accepted by specialists that, whatever the 
 ultimate origin of volcanic action may be, the- surface effects 
 are due to the explosive escape of accumulations of steam sud- 
 denly released from pressure. This explanation is based upon 
 accurate observation of the quiet workings of the miniature 
 volcanoes of the Lipari Islands, in the Mediterranean, and 
 upon the evidence obtained during the more violent, apparently 
 paroxysmal, outbursts of Vesuvius, Etna, Tarawera, Kilauea 
 and Krakatoa. 
 
 The volcanic rocks of the Cripple Creek district have come 
 up through the granite. It underlies them all ; they rest upon 
 it, and can be seen penetrating it in the form of dikes. Pre- 
 vious to the first eruption, the granite must have presented 
 a weather-worn surface, such as characterizes the high hills. 
 Ever since its first emergence from the ocean this region has 
 been undergoing an intermittent elevatory movement, which 
 culminated in making the Front range. Erosion had been con- 
 tinuous, but the uplift more than counterbalanced such wear- 
 ing away ; and the granite hills had been slowly raised far above 
 the Cretaceous seas which washed their edges in the era pre- 
 ceding that to which the eruption is assigned. The forces 
 which had done this work were of the most patient kind ; their 
 
 fessor Milne, thus: "The earth became solid under two influences; it began to 
 solidify at the surface by cooling, the crust growing thicker and thicker ; and it 
 began to solidify at the center by pressure, the core growing larger and larger. 
 This double phenomenon of solidifying continued until a solid outer shell and a 
 solid inner core came close together in what may be called the critical region of 
 the earth, the region which feeds lava to volcanoes." 
 
THE CRIPPLE CREEK VOLCANO. 9 
 
 manifestation had about it nothing of a violent or paroxysmal 
 character; time was an essential element of the process. 
 
 At the close of the Eocene period this apparent equilibrium 
 was disturbed. The foundations of the granite hills trembled. 
 Slight tremors were followed by earthquakes, and these were 
 the precursors of greater violence. 
 
 Earthquakes usually precede an eruption. In certain vol- 
 canic regions, such as the north island of New Zealand and 
 Japan, the minor shocks, designated as " tremors," are of daily 
 occurrence. They represent the vibrations set up by the sud- 
 den generation of steam from water coming into contact with 
 the upwelling lava. It is water-vapor, and not smoke, which 
 is emitted by volcanoes.* This water is derived from the sur- 
 face, having sunk into the soil, permeating the more porous 
 sedimentary rocks, lodging in the crevices of unstratified for- 
 mations, and becoming stored underground, as mine-explora- 
 tions testify. Where the country surrounding the volcanic 
 vent has become covered with the products of previous erup- 
 tions, the loose character of the soil, resulting from the dis- 
 integration of scoriaceous lava, facilitates the descent of the 
 rains, and tends to the accumulation of large quantities of 
 water. Moreover, the vibrations set up by the superheated 
 steam cause fissures which allow distant bodies of water, from 
 subterranean reservoirs, fresh-water lakes,f or, if the volcano 
 be situated near the coast, the ocean itself, to be let downj sud- 
 denly into the volcanic vent and into explosive contact with the 
 incandescent lava. Humboldt found small fishes in the water 
 
 * Volcanoes are not necessarily mountains. The mountain is the result of the 
 volcano, and not vice versa. It is the accumulation of the material ejected from 
 the vent which slowly builds up the cone. Many emissions of lava occur at the 
 base of mountain ranges and have quietly overspread the surface from fissures, 
 much as water rises through cracks in the ice and overspreads it, when a heavy 
 wagon presses it down. The lava-plains of the Snake river, traversing Oregon 
 and Idaho, afford an example; so does the Deccan (India), where successive, 
 nearly horizontal, flows, covering an area of 200,000 square miles, have reached 
 a thickness of 6000 feet. 
 
 f Lake Rotomahana was drained at the time of the eruption of Tarawera, in 
 New Zealand, in 1886. 
 
 J Mosely (Notes by a Naturalist on the Challenger, p. 503) mentions that, in 
 1877, when on board the "Challenger," he saw the sea- water actually pouring 
 down into a fissure formed in the bed of the sea off the Hawaiian coast. The fis- 
 sure was traced to the shore and three miles inland. This occurrence was con- 
 nected with the volcanic activity of Mauna Loa, on the neighboring island of 
 Hawaii. | Controverted Questions of Geology, Prestwich, p. 116. 
 
10 THE CRIPPLE CREEK VOLCANO. 
 
 emitted from fissures caused by earthquakes in the Andes. 
 Diatoms, the microscopic forms of life characterizing the deep 
 sea, have been found in the volcanic ejections of the Pacific 
 islands. Where volcanoes are in proximity to the ocean it has 
 been found that among the emanations from the lava there 
 exist, not only chlorides, but also sea-salt itself. A sudden 
 diminution of the water-supply in wells and springs near 
 Naples has been repeatedly observed to presage the eruption of 
 Vesuvius. 
 
 There is therefore ample evidence that water does penetrate 
 into the conduit of the volcano, and that it is originally derived 
 from the surface. As against the contrary belief, namely, that 
 the water-vapor accompanying eruptions is an essential con- 
 stituent of the lava, and therefore shares with it a deep-seated 
 origin, there is the following evidence. It has been found, as 
 the result of a large number of accurate observations in wells, 
 shafts and bore-holes, that the temperature underground in- 
 creases 1 F. for every 48 feet of descent.* At 7776 feet, the 
 boiling-point, and at 34,700 feet, the critical point, 773 F., of 
 water, would be reached. The expansive force of steam in- 
 creases rapidly with the temperature, so that at 773 F. it would 
 be equal to the pressure of 350 atmospheres. f This is termed 
 the "critical point," because, at this temperature, water, how- 
 ever great the pressure to which it is subjected, can no longer 
 exist as a liquid, but becomes dissociated into its constituent 
 gases. Although the exact conditions which obtain at these 
 great depths cannot be known with certainty, nevertheless, 
 all the evidence goes to show that there is a limit set to the 
 descent of surface-water by the rapid increase in the expansive 
 force of its vapor, due to the rising temperature. PrestwichJ 
 put the maxim limit at 6 to 7 miles, and Delesse estimated it 
 
 * ''On Underground Temperatures," Sir Joseph Prestwich. Proceedings of the 
 Royal Society, February, 1885. Of course this increment of 1 degree per 48 feet 
 can only apply to the outermost portion of the earth. Beyond a few miles of 
 depth there must exist conditions of which very little can be inferred. There, 
 the enormous pressure probably counteracts the expansive effects of heightened 
 temperature, and upsets many of the conclusions of physics which hold good near 
 the surface. 
 
 t Which, at 15 Ibs. per square inch for each atmosphere, amounts to about 2J 
 tons per square inch. 
 
 J Controverted Questions of Geology, p. 93. 
 
 g Bulletin Societe Geol. de France, vol. xix., p. 64. 
 
THE CRIPPLE CREEK VOLCANO. 11 
 
 at 60,000 feet, or about 11 miles. Moreover, experience goes 
 to show that the water encountered in mines is the drainage 
 from the surface. Deep mines are usually dry ones. I may in- 
 stance the deepest metal-mines, the Calumet-Hecla and Tama- 
 rack, in the Lake Superior region, and the "180," "New Chum- 
 Victoria," and neighboring shafts, at Bendigo, in Australia. 
 
 The evidence obtainable concerning the first eruption of the 
 Cripple Creek volcano is necessarily very meager. The first 
 vent must have been formed at some point along one of the 
 fractures caused by the earthquake-shocks; the lava, in forcing 
 for itself a way to the surface, being aided by the force of the 
 expanding steam. The pressure required to break a passage 
 through the overlying rocks is stupendous ; and, as a conse- 
 quence, when the steam accompanying the lava is finally, and 
 very suddenly, released from that pressure, on its immediate 
 arrival at the surface, it escapes with explosive energy, and with 
 projectile discharges which may reach to an astonishing height. 
 Thus, when the outburst of Krakatoa, an island near Java, oc- 
 curred in 1883, the finer fragments ascended skyward 10 miles, 
 and were recognizable* in the atmosphere of London. The 
 winds carried the dust of Krakatoa round the world, and thus 
 gave rise to the extraordinary sunsets observed in the autumn 
 following. 
 
 The material ejected during the first outburst of a volcano 
 consists of fragments of rock torn from the sides of the vent- 
 The extinct volcano of the Kammerbuhl, already mentioned in 
 this paper,f exhibits pieces of burnt slate within the mass of 
 the scoria forming its cone. The underlying formation consists 
 of slates and other metamorphic rocks. 
 
 The Cripple Creek volcano first ejected fragments of granite. 
 These were probably small in size, and became further re- 
 duced by colliding with each other as they were discharged, 
 so that they fell to earth in showers of particles like gravel. Of 
 this first eruption there is little trace now, unless the grits of 
 Straub and Grouse mountains be the remnants, as is probable, J 
 
 * The writer, then a student at the Koyal School of Mines, saw this volcanic 
 ash under the microscope after it had been collected from the London atmosphere, 
 which hardly needed solid contributions from such a distant source. 
 
 f See Fig. 1 and the corresponding text. 
 
 J This is the opinion of Whitman Cross. See page 71, op. cit. 
 
12 THE CRIPPLE CREEK VOLCANO. 
 
 of the debris accumulated at that time. Material resembling 
 this must certainly have covered the surface around the vent, 
 until the larger portion of it was washed away. The steam 
 which, in enormous volumes, accompanies the first outbursts 
 of volcanic action, becomes condensed as soon as it issues into 
 the cold air and forms rain-clouds, the downpouring of which 
 frequently removes the accumulations formed at the inital stage 
 of the volcano. The floods which succeed eruptions are due to 
 the super-saturation of the atmosphere with the water-vapor 
 emitted by the volcano. Such floods are more feared by the 
 dwellers around Vesuvius, for example, than the lava-streams, 
 the destructive effects of which are comparatively restricted. It 
 was the formation of a liquid mud, by the action of heavy rains 
 on the fine material, called " tufa," which buried the city of 
 Herculaneum. 
 
 It is unlikely that sufficient data will ever be forthcoming to 
 give an exact presentation of the chief vent of the Cripple 
 Creek volcano, unless one of the millionaires, enriched by the 
 gold he has won from the mines, shall prove as public-spirited as 
 Goethe's friend, and shall undertake the requisite explorations. 
 Yet some very interesting evidence on this point is available. 
 A miniature vent* exists near the town of Victor, and the 
 railroad has cut through it, so as to furnish the section of it 
 shown in Fig. 2. As a hand-specimen may exemplify the 
 structure of a mountain range, so this small vent typifies many 
 of the characteristics of the orifice probably existing in the 
 earlier stages of the Cripple Creek volcano. 
 
 This vent occurs in the massive granite of Squaw mountain, 
 about 1700 feet south of the main breccia-formation of Battle 
 mountain. In the railroad-cut, where it is to be seen, it has a 
 width of 35 feet. It is filled with fragments of granite and the 
 gravel derived from the brecciation of granite. The edges are 
 not particularly well-defined, because the face of the enclosing 
 rock is shattered. The most peculiar feature of the section is 
 presented by pellets, nodules and rounded fragments of dark- 
 red scoriaceous lava, which occur all through the material filling 
 the vent. At the edges, rounded inclusionsf of this lava can be 
 
 * Whitman Cross describes this vent on page 77 of his Cripple Creek report. 
 
 f The largest are 1 to 1 inches in size. On microscopic examination Professor 
 Kemp found it difficult to determine the exact petrographic character of this lava. 
 "It shows only alteration products in some parallel arrangement, but not in sig- 
 
THE CRIPPLE CREEK VOLCANO. 
 
 13 
 
 seen in the mass of fragmentary granite ; and in the center the 
 lava, by reason of oxidation, forms a red granular matrix, in 
 which large pieces of granite are separately discernible. The 
 
 -^- r^-^V-w. iv ^v A - 
 
 " 
 
 : ^^^^Si^S^^^^^$;^M 
 
 material, especially near the edges, has a laminated structure, 
 parallel to the sides of the vent. These laminations vary in 
 thickness according to the coarseness of the material. 
 
 nificant condition." In both of the specimens I sent to him he detected large 
 scales of biotite. Having in view this fact, and the character of the material, it 
 seems most probable that the lava closely resembles the rock of the basaltic dike 
 in which the neighboring Anna Lee ore-chimney was found to occur. 
 
14 THE CRIPPLE CREEK VOLCANO. 
 
 This illustration is of great interest. The vent is in granite, 
 as was the first vent of the volcano. It is now filled with breccia, 
 as, at one time, that was. The shattering of the sides is sug- 
 gestive of the mode of formation of the breccia, which now fills 
 it. Had this vent been further enlarged, and subsequently pene- 
 trated by phonolite, not in fragments, forming a breccia, but in 
 liquid form, solidifying to a compact mass, it would have pre- 
 sented a complete analogy to the Cripple Creek volcano. 
 
 As another example, but from a different locality, of a 
 natural section of a small vent, I would instance that shown in 
 Fig. 3, which represents a drawing recently made by Sir Archi- 
 bald Geikie,* while traveling among the Faroe Islands, in the 
 North Atlantic ocean. The action of the waves has cut down 
 the face of the cliff, so as to exhibit its structure very clearly. 
 The vent occurs in banded lava (A A) and has a diameter of 
 about 100 yards. It is filled with agglomerate (B) consisting 
 of compacted debris, in which lie large fragments of slaggy 
 lava, the largest being in the center of the former orifice. The 
 filling is arranged in distinct layers toward the sides. The top 
 of the vent is saucer-shaped, and is covered with three succes- 
 sive fiows of basalt (D, G, E) ; of these, the lowest has merely 
 extended over the center of the vent, while the next (D) nearly 
 covers it, and the uppermost (G) lies over the whole of it. 
 Above these there are other layers of basalt (E, F) which com- 
 pletely bury the orifice. 
 
 After the first outburst, a change took place in the matter 
 ejected by the Cripple Creek volcano; there began to appear 
 the fragmentary andesite which was destined to be accumulated 
 to such an enormous thickness. It may be that flows of ande- 
 sitic lava also welled out over the surface at this time. If so, 
 they were subsequently eroded. During the long intervals of 
 quiet separating one period of eruption from another, the lava 
 became cooled, cracked, arid then disintegrated by rain and 
 frost, so as to be broken up and -carried away by the moun- 
 tain streams to form a part of the alluvium of the valleys. 
 Thus the superficial flows were removed ; but the corresponding 
 bodies of lava which consolidated underground, when the ex- 
 trusion at the surface had ceased, are now, thanks to that very 
 
 * "The Tertiary Basalt Plateaux of North Western Europe." Quarterly 
 Journal, Geological Society, vol. lii., page 344. 
 
THE CRIPPLE CREEK VOLCANO. 
 
 15 
 
 erosion, to be seen as bodies of andesite rock in several parts of 
 the district, notably on the eastern side of Battle mountain and 
 near Legal Tender Hill, above Goldfield.* 
 
 The fragmentary eruption of andesite continued. At this 
 time the volcano must have been a splendid sight, especially by 
 
 night. It was so late in geological time that Pike's Peak was 
 already a giant among its fellows, and towered in lonely 
 grandeur above the lesser hills where the eruption was taking 
 
 * As the accompanying geological map (Fig. 4 ) of the district illustrates. This 
 map is a reduced copy of the colored map published by the United States Geo- 
 logical Survey. The ideal section which I have drawn (Fig. 5) is taken in an 
 east and west line across the southern part of the area. 
 
16 
 
 THE CRIPPLE CREEK VOLCANO. 
 
 FJC,*: 
 
 f 4- 4- 
 
 4- + * -V 4 . 4- -f 4 
 1-4-* 4 4 -f- <- ... 4. 
 
 J_ _!___ _L i 
 
 + 4 
 * 
 
 4 - - 4- + t jjA! 
 
 4-44^ _4-x ^^rl 1 
 
 f * t + X /T 'xv^ + 
 
 4- 4 +jf+*rt^' 
 
 4 + + ^tA - -H 
 
 . .^^a +^ -+x T- iv "t* ii 
 
 aii^^Mi 
 
 ^ + " BR G ^riMBI^ +*/.*%** ** *t****f 
 
 +X+^H& 1 "* |piBPr''-% % *V r *- % **%% 
 
 4- 4- --^^^4. t^B^^^^/4- 4- 4 ^H-1- 4 - t-44-i- 
 
 , Scale , l mile 
 
 Trachytic Phonolfte [_p Andesite flB Nepheline-Syenite / Basalfr 
 
 ^JP Phonolite $'<:'j Andesite Breccia ["+ . fl Granite^ 
 
 Nepheline-Syenite 
 ^"} Granite^ 
 ^^5 Arkoee Gravels 
 
 | Rhyolite 
 
 GEOLOGICAL MAP OF THE CRIPPLE CREEK DISTRICT. 
 (After U,S. Geological Survey.) 
 
 r Diabase 
 
 ,. . 
 
 place. The shifting lights of the volcano were reflected by the 
 snow-fields of the peak. Those lights were due to the glow of 
 
 * 
 
 snow 
 the 
 
 -es o te pea. ose gts were ue to te gow o 
 incandescent lava in the crater thrown upon the clouds* of 
 
 * Professor Judd very aptly likens this effect to that caused when, at night, 
 the engineer of a locomotive pulls ppen his furnace door and permits the light of 
 the fire to be thrown upon the stream of vapor issuing from the funnel. 
 
THE CRIPPLE CREEK VOLCANO. 
 
 17 
 
 watery vapor which hovered overhead. To this appearance* 
 were added lightning-flashes. The steam issuing through the 
 
 Hir 
 
 ^r,-m$$m / 
 
 '^t'^&m^ 
 
 10 S 1 U r i^V^K'^"'''"''^^ 
 
 2 Wi^SS^ n 
 
 141 W^iftbalfe^l 
 
 x i:^/s5 
 . ; v,\rv 
 
 ' > N .- ;: ^; 
 
 $m 
 
 oc 
 > o 
 
 1 1 
 
 orifice of a volcano is highly charged with electricity, generated 
 by its upward rush, and the friction of the colliding particles 
 
 * The old idea of a volcano was a mountain which spouted fire, ashes and 
 smoke. The "fire" is the reflection referred to above ; the "smoke" is vapor ; 
 the "ashes " are lava rendered vesicular or pumice-like by the bubbles of steam 
 penetrating fused rock. 
 
 2 
 
18 THE CRIPPLE CREEK VOLCANO. 
 
 of solid matter ejected with the steam contributes further in 
 producing a condition of intense electrical excitement. This 
 is relieved by discharges into the surrounding atmosphere. 
 
 The lightning illuminated the surrounding hills and shone 
 around Pike's Peak; the hurtling of the fragments of rock as 
 they met in mid-air and the sound of their fall as they rattled 
 down the slope of the volcano mingled with the muffled roar 
 of escaping steam and the occasional rumbling of the thunder. 
 
 There was none to see it. Man was not yet on earth, though 
 the footsteps of his oncoming could almost be heard.* Of 
 animal life no traces have been found in the Cripple Creek 
 formation. Bird and beast fled from the terrible sights and 
 sounds. But remnants of the vegetation of that time have 
 been preserved, and at depths of many hundred feet beneath 
 the surface of to-day the miner has encountered the remainsf 
 of trees, resembling pines, which were overwhelmed by the 
 eruption. 
 
 At this period similar outbursts .were occurring among the 
 neighboring hills, for the Cripple Creek volcano was but a 
 minor incident among the eruptions which, during the Tertiary 
 epoch, spread a vast thickness of breccia and lava over a large 
 portion of southern Colorado. Out of the products of these 
 eruptions were sculptured the serrated peaks of the Uncom- 
 paghre, the Cochetopa hills, and the rugged ranges of the San 
 Juan. 
 
 After the eruption had continued sufficiently long to form a 
 vast accumulation of the fragmentary materials, which in pro- 
 cess of time became consolidated into breccia, there came a 
 period of comparative quiet. 
 
 * The earliest vestiges of man belong to the close of the Miocene period. 
 
 t These are various. In the Jack Pot mine, at 400 feet from the surface, in the 
 Logan at 600 feet, and in the Doctor at 700 feet, there have been found fragments 
 of coal, exhibiting traces of wood -structure In the Independence, at 5CO feet, a 
 stump of a tree was discovered in the very midst of rich ore In every case the 
 enclosing rock was breccia. The specimen from the Independence is stone, the 
 others are coal. In the former case, the tree-portion must have become buried 
 under conditions free from access of air, and must have been subjected sub- 
 sequently to the action of siliceous waters, which gradually replaced the fiber of 
 the wood with a mineral precipitate. In the other cases, the tree must have be- 
 come enclosed within the breccia and subjected to a slow oxidizing action which 
 carbonized the wood, without permitting it to burn freely. Otherwise, it would 
 have been destroyed, leaving only ashes As it was, it became coal, carrying 60 
 per cent, carbon, and having the other characteristics of a typical lignite. 
 
THE CRIPPLE CREEK YOLCANO. 19 
 
 The Cripple Creek volcano must have formed a conspicuous 
 mountain. This is inferred from the nature of the material 
 ejected. The size and shape of the cones formed by the emis- 
 sions of a volcano depend upon the condition in which they 
 are emitted. Limpid lavas, like those of the Hawaiian vol- 
 canoes, form extremely flat cones. Mauna Loa, for example, 
 has a height of 13,675 feet above the sea, with a base of over 
 70 miles, the slopes having, according to Dana, an angle of 
 4 to 6 only. The great volcanic cones of the Andes are 
 made up of a much less liquid lava, and, according to Whym- 
 per, have slopes which range from 27 to 37. Mount Shasta, 
 in California, which is built up of similar rocks, stands, accord- 
 ing to Whitney, at an angle ranging from 28 to 32. A cone 
 such as that formed around the vent of the Cripple Creek vol- 
 cano, which emitted vast quantities of fragmental material 
 alternating with occasional lava-flows of the more viscid type, 
 would partake of the character of the well-known puys or peaks 
 of Auvergne, which dot the surface of that part of south-central 
 France, in shapes resembling a candle-extinguisher. Breccia 
 and lava together make steeper cones than lava or breccia 
 separately ; therefore the Cripple Creek volcano, when at its 
 maximum height, must have appeared as a steep mountain. 
 
 Projectile discharges were succeeded by tranquil emissions 
 of lava. The bodies of massive andesite in the southeastern 
 part of the district may represent such extrusions. They were- 
 marked by an absence of the violence which accompanied the 
 earlier outbursts, due, perhaps, to a diminution in the quan- 
 tity of escaping steam and a lessening of the pressure upon that 
 which remained. The earlier ejectamenta of a volcano are 
 scoriaceous and vesicular ; that is, they have been penetrated and 
 torn by the explosive escape of superheated water-vapor, while 
 the lava characterizing the later stages of activity is compact 
 and homogeneous. The creation of a vent serves as a safety- 
 valve in releasing the tremendous pressure of the steam, due to 
 its sudden expansion when coming into contact with incandes- 
 cent fused rock. Attendant upon the relief given to that pres- 
 sure, are all the terrifying phenomena of the first outburst. Sub- 
 sequently the force of the eruption diminishes. The lava ceases 
 to be violently projected by escaping high-pressure steam. The 
 underground waters near the conduit have become used up. 
 
20,: 
 
 ' > s J> 
 
 I* i *,j 
 
 THIS CRIPPLE CREEK VOLCANO. 
 
 The rise of the lava underground, followed by its protrusion at 
 the surface, becomes a quiet process, which must be referred to 
 a more deep-seated cause, namely, the local readjustment of 
 the earth's crust, causing the fused rock to ooze out slowly. 
 Many lava streams have a glacier-like movement. They seldom 
 progress more than 3 miles per day, and often require a year 
 to advance a few miles.* Observers have described the flows 
 of lava which follow the first eruption as welling out " with the 
 tranquility of a water-spring,"f as " proceeding in silence,"J 
 as " being effected quietly and without noise. " All this is in 
 vivid contrast to the paroxysmal outburst which marks the first 
 stage of volcanic activity. The difference is to be referred to 
 the relative quantity of steam taking part in the process of 
 eruption. 
 
 The period of quiet may have been, and probably was, suc- 
 ceeded by a complete, though temporary, cessation of activity. 
 This interval may have persisted for several hundred years. 
 Geology is lavish of time. The inaction was due to the diminu- 
 tion of pressure consequent on. the withdrawal of the lava in 
 the conduit of the volcano. Such a result would be brought 
 about by the shifting of the center of eruption to another place 
 along the line of fissure. The island of Yulcano, in the Lipari 
 group, affords an excellent example of such a change of vent. 
 Among the extinct craters of Auvergne|| in south-central 
 France, similar instances are numerous. (See Fig. 6.) The 
 first conduit of the Cripple Creek volcano became plugged up 
 by material which had failed of ejection. Other minor vents 
 may have been formed on the flanks of the mountain which 
 had been slowly formed by the long continuance of discharges. 
 When, after an interval, a vigorously active condition was re- 
 sumed, the second eruption, in all probability, took place 
 through a new vent, produced, as the original one had been, 
 by a fissuring of the rock immediately over congested masses 
 of steam due to the water which had accumulated during the 
 interval of inaction. 
 
 * Dana. f Scrope. J Fouque. \ Ibid. 
 
 || The writer cannot claim to have any special knowledge of volcanoes, but he 
 is familiar with the volcanic region of Auvergne, in south-central France, has 
 seen Vesuvius, and has traveled in the volcanic parts of New Zealand, and also 
 in Oahu, one of the Hawaiian Islands. 
 
THE CRIPPLE CREEK VOLCANO. 
 
 21 
 
 There is evidence indicating that the Cripple Creek volcano 
 had several vents. One existed near the present site of the 
 Hull City placer ; another must have been situated near Ana- 
 conda. The original position of the orifice of an extinct vol- 
 cano can be inferred from the composition of the rocks. The 
 lava which cools rapidly in the open air assumes the character 
 of a glassy substance,* containing only a few embryonic 
 
 FIG. 6. 
 
 SECTION 
 THE PUY DE PARIOU, AUVERGNE. 
 
 ILLUSTRATWG THE SHIFTING OF ERUPTION ALONG A LINE OF FISSURES. 
 (AflfeaJudd.) 
 
 crystals, but that which cools slowly underground, and while 
 still subjected to great pressure, is developed into completely 
 crystalline rock. Experiments with smelter-slags, and a micro- 
 scopic examination of the resulting material, have confirmed 
 this proposition. In this way the lava streams which have 
 issued from the vent are distinguishable from the material 
 
 * On June 3, 1840, a stream of lava from Kilauea reached the sea, after having 
 flowed over the island of Hawaii for a distance of 11 miles. " The burning lava, 
 on meeting the waters, was shivered like melted glass into millions of particles, 
 which were thrown up in clouds that darkened the sky and fell like a storm of 
 hail over the surrounding country." DANA, Characteristics of Volcanoes, page 63. 
 
22 THE CRIPPLE CREEK VOLCANO. 
 
 which has solidified in the throat of the volcano. The nephe- 
 line-syenite near the Lillie and Vindicator mines is the granular 
 equivalent of the phonolite which occurs so plentifully all over 
 the district. The phonolite and the syenite have a similar 
 chemical composition, but their texture is very different. This 
 is due to the fact that in the former a crystalline structure has 
 not been fully developed, but the ground-mass or matrix, as 
 seen under the microscope, being made up of crystallites, 
 minute, hair-like bodies without the properties, but with the 
 tendency to become, crystals. This indicates that the rock 
 cooled too rapidly to permit of proper crystalline growth. The 
 nepheline-syenite, on the contrary, is made up entirely of de- 
 veloped minerals, no part of the original ground-mass having 
 failed of arrival at true crystalline maturity; so that even the 
 slight excess of quartz, though uncombined, presents a crystal- 
 line structure. This indicates that the rock cooled very slowly, 
 giving ample time for the full play of the forces which pro- 
 duce crystallization. It is to be inferred that the nepheline- 
 syenite fills an old vent, or is close to it. The same inference 
 is drawn from the patch of syenite-porphyry between Gold hill 
 and Squaw gulch. Further evidence suggestive of the former 
 existence of a vent thereabouts is afforded by the steepness 
 of the plane of contact between the granite and breccia on 
 the adjoining Guyot hill. The dissection of extinct volcanoes 
 in other parts of the world, a dissection brought about by 
 natural erosion, which has cut valleys right into the flanks of 
 ancient eruptive centers, furnishes numerous examples con- 
 firming such deductions as have just been made with reference 
 to the vents of the Cripple Creek volcano. Even in Great 
 Britain, which has not known volcanic disturbances during the 
 time covered by the brief record of human life, there are abun- 
 dant proofs concerning the shifting of vents and the resulting 
 relations between perfected and undeveloped rock-types. 
 
 The occurrence of several vents would not be unusual. Vol- 
 canoes are not mere bores through which eruptive discharges 
 take place. Where one single vent survives, it may be con- 
 sidered to represent the centralization of energy due to the 
 choking-up of many other openings along the line of fissure 
 formed at the time of the first manifestation of activity. This 
 is well illustrated in the accompanying sketch of Mount Etna, 
 
THE CRIPPLE CREEK VOLCANO. 
 
 23 
 
 as it appeared in 1865. (See Fig. 7.) The expansive force of 
 the steam, to which the violence of the initial stages of vol- 
 canic action is due, tends to radiate from the central point of 
 energy so as to form cracks, the character and extent of which 
 will vary according to the structure of the rocks through which 
 the shocks are propagated. At certain points along these 
 cracks, or at the crossing of two of them, openings are formed, 
 permitting eruptive discharge. Those openings which are im- 
 mediately above the points of greatest pressure, will survive 
 longest; the others become plugged up with the material they 
 are unable to eject. One vent usually remains as the center of 
 
 Monte Frumento, an old Parasitic Cone B B Line of Fissure C C C New Scoria Cones 
 
 D D Lava, from the small Scoria Cones 
 
 FISSURE FORMED ON THE FLANKS OF MT. ETNA IN 1865. 
 
 (After Judd.) 
 
 energy. The others become extinct, until an increase of erup- 
 tive activity finds a single conduit insufficient, and thus neces- 
 sitates the obtaining of relief at other points. Lava-flows do 
 not necessarily take place at the central .vent. Many of the 
 largest flows known to have occurred among the Hawaiian 
 volcanoes, for example, have emanated, not from the crater at 
 the top of the mountain, but far down upon its flank. In cer- 
 tain instances, as at Kilauea,* the larger number of discharges 
 have been subterranean. 
 
 The subterranean discharges of lava are of peculiar interest 
 
 * Dana. That of July, 1840, started at a point 16 miles distant from the crater. 
 
24 
 
 THE CRIPPLE CREEK VOLCANO. 
 
 to the miner, because they are among the factors which he has 
 found by experience to influence the distribution of the ores 
 which he seeks. They are to be seen both in natural sections, 
 afforded by ravines, and in those other sections of the rocks 
 which are presented underground in the mines. , The accom- 
 panying drawing,* after Fouque (see Fig. 8), of a natural sec- 
 tion seen on the slope of the old volcano of Santorin, will be 
 suggestive. These intrusions take a variety of forms. Such 
 as seek out the lines of weakness presented by the bedding- 
 planes of sedimentary rocks, or the lines of successive deposi- 
 
 FiG.8, 
 
 Lava flows 
 
 Dykes 
 
 f Scoria and Ash 
 
 SECTION ON THE SLOPES OF THE OLD VOLCANO OF SANTORIN 
 (After Fouque) 
 
 tion of fragmentary volcanics, form sheets. In England, such 
 an intrusive sheet is termed a "sill." An instance is illustrated 
 in the accompanying section, obtained in the western islands of 
 Scotland by Sir Archibald Geikie.f (See Fig. 9.) The intru- 
 sive masses of porphyry (quartz-felsite) which, at Leadville, 
 penetrate the sedimentaries, afford an example which is of 
 peculiar interest on account of the remarkable ore-deposits 
 found at the contact of the porphyry with the Carboniferous 
 limestone. 
 
 * From Santorin et ses Eruptions. 
 
 f " The Tertiary Basalt-Plateaux of Northwestern Europe." Quarterly Journal 
 Geol. Soc., vol. lii., p. 377. 
 
THE CRIPPLE CREEK VOLCANO. 
 
 25 
 
 Those subterranean flows of lava which do not find a ready 
 passage, either in a lateral or a vertical direction, tend, when 
 thus impeded, to congest locally, so as to form huge under- 
 
 CQ 
 
 ground blisters which are sometimes large enough to arch the 
 overlying strata into dome-shaped hills. Such " laccolites,"* 
 as they are termed, were first recognized as a type by G. K. 
 
 * From the Greek lakkos, cistern, and lithos, stone. Laccolith would be a better 
 form. 
 
26 
 
 THE CRIPPLE CREEK VOLCANO. 
 
 Gilbert.* Since then, Whitman Crossf has described similar 
 occurrences in southwestern Colorado. The accompanying 
 drawing (Fig. 10) represents his ideal section of one of these 
 enormous cores of what was once fused rock. In this particular 
 section, of Mount Marcellina, it is evident that the porphyrite 
 has arched the overlying coal-bearing strata to the point of rup- 
 ture, a line of fracture being indicated to the right of the 
 laccolite. 
 
 Such intrusive masses as have been described are encoun- 
 tered by the miner with much less frequency than the dikes, 
 which are approximately vertical sheets of igneous rock, evi- 
 
 FIG. 10. 
 
 THE LACCOLITE OF MT. MARCELLINA 
 (After W.Cross) 
 
 AM, BANK NOTE CC.,N.Y. 
 
 dently filling cracks which usually extend to a depth greater 
 than any existing mine-workings. In underground explora- 
 tions we sometimes come across dikes which have failed to 
 reach the surface ; and, more rarely, it has been found that the 
 lower end of one of these vein-like bodies merges into the very 
 heart of a large mass of similar rock. It is inferred that every 
 dike emanates from some central core, because a purely local 
 origin is not conceivable ; the conditions which induce liquefac- 
 tion and those which compel the upthrust of the fused rock 
 are alike referable to factors created by the forces at work 
 
 * " Report on the Geology of the Henry Mountains," 1877. 
 
 f " The Laccolitic Mountain Groups of Colorado, Utah and Arizona." 
 
 Uth 
 
 Annual Report, U. S. Geol. Suwey. 
 
THE CRIPPLE CREEK VOLCANO. 27 
 
 v> 
 
 within large masses of rock. The water coming up through 
 a crack in the ice is referred to the body of it beneath that ice. 
 The fused rock rises in the fractures caused by earth-move- 
 ments much as the water fills the cracks in the ice; that is, no 
 gaping crevasse is necessarily formed, but the lava rises and 
 occupies the fracture as it is formed ; it follows it, it does not 
 make it, although the movement which makes the crack and 
 the pressure which squeezes the lava into it may both be trace- 
 able, far back, to a common cause. 
 
 The behavior of -dikes often affords striking evidence of their 
 adaptability to the structure of the rocks they traverse. They 
 seek out lines of least resistance, and thus frequently make 
 evident structural features which otherwise would have been 
 merely latent. The accompanying drawing (Fig. 11) illus- 
 trates this. It represents a flat surface of granite (in West 
 Australia) traversed by a dike of dolerite, which has evidently 
 utilized for its passage the lines of fracture produced along a 
 sheer-zone in the granite. The very low conductivity of lavas 
 (as of smelter-slag) may explain their ability to pass through 
 rock-fractures for great distances. The edges of a dike would 
 cool instantly, but in so doing would afford a protection to the 
 central portion, the liquidity of which would thus tend to be 
 maintained. 
 
 The bulk of the material thrown up by the Cripple Creek 
 volcano was fragmentary, and became the great mass of 
 breccia now constituting the leading geological feature of the 
 district. The earliest lavas extruded were of medium fusi- 
 bility : namely, andesite, and then phonolite. On reaching 
 the surface, they formed streams, the exterior of which became 
 promptly chilled to a black-looking slag, to which escaping 
 steam gave a cindery structure. The lava rolled down the 
 slope of the volcano with the utmost slowness, making clinking 
 sounds such as are heard when the workmen empty the slag- 
 pots over the dump of a smelter. Such lava-streams weather 
 very easily ; their exterior, by the contraction of the surface due 
 to cooling, becomes porous, and water penetrates into the mass 
 of them, disintegrating them so that they are readily carried 
 away by the rains of spring. 
 
 The last extrusions of the Cripple Creek volcano were of 
 basalt. These were more limpid, and must have formed 
 
28 
 
 THE CRIPPLE CREEK VOLCANO. 
 
 4 -f 
 
 + 4j 4-+ 4- + + 
 
 Dike 
 
 Granita 
 
THE CRIPPLE CREEK VOLCANO. 29 
 
 streams which traveled much farther than the less fusible 
 phonolite and andesite. The basalt, judging from the be- 
 havior of similiar lava-flows actually observed in the Hawaiian 
 Islands and elsewhere, would progress rapidly down the slopes 
 of the mountain and overwhelm the forests which, probably, 
 clothed the lower portions of the Cripple Creek volcano, setting 
 them on fire and adding greatly to the aspects of destruction 
 presented by the scene. Upon cooling, these basaltic flows 
 would be cleft asunder by symmetrical series of cracks forming 
 prismatic columns grouped like the pillars of a Gothic cathedral. 
 But where they were not protected by a later covering of rock, 
 the ruthless hand of decay attacked them also, the frost of 
 many thousand years shivered the straight columns ; and the 
 freshets of spring swept the remnants into the torrents which 
 fe.d the Arkansas river. 
 
 The successive periods of activity in the life of the Cripple 
 Creek volcano are marked by the sequence of lavas extruded. 
 This sequence is indicated by structural relations, the older ex- 
 trusions being penetrated by the younger. But this is not all. 
 The crystalline structure and the chemical composition of the 
 rocks resulting from the cooling and consolidating of the 
 successive lavas exhibit differences which have been found to be 
 closely analogous to those presented by similar successions of 
 rock at other volcanic centers, both in the United States and in 
 Europe. The earliest lava extruded by the Cripple Creek vol- 
 cano was andesite. Then came the phonolite, and, lastly, the 
 basalt. These three rocks represent types which vary in their 
 chemical composition and in their consequent fusibility. Basalt 
 fuses at about 2250 F. ; certain varieties fuse at about 2000 
 F. What is usually termed a " white heat " is equivalent to a 
 temperature of 2100 F*. The least fusible rocks are of the 
 granite and trachyte class ; they fuse with difficulty at about 
 2700 F. To the intermediate type belong the andesites, which 
 fuse at about 2520 F.f The relative fusibility of these rocks 
 is dependent upon the fusibility of their chief constituent, feld- 
 
 * According to the latest determinations by Henry M. Howe. According to 
 Pouillet's experiments, gold melts at 2192 and silver at 1832 F. See Eng. and 
 Min. Journal, Jan. 20, 1900, p. 75. 
 
 t These are the temperatures derived from the experiments of Carl Barus. 
 See Dana's Manual of Geology, p. 273. 
 
30 THE CRIPPLE CREEK VOLCANO. 
 
 spar, the variety in the basalts being labradorite, the most fusi- 
 ble of the feldspars. Moreover, in basalt there is present a 
 good deal of augite, a still more fusible mineral, and a large 
 percentage of iron which, as in smelter-slags, contributes di- 
 rectly to fusibility. The trachytes are largely made up of 
 orthoclase, the least fusible of the feldspars. The andesites 
 are intermediate in composition and of medium fusibility, their 
 characteristic feldspar being oligoclase. 
 
 This fusibility used to be expressed in terms of " acid " and 
 " basic character^' the rocks high in silica and low in iron being 
 at one extreme, and those low in silica and high in iron at the 
 other. But Dana has pointed out* that this does not express it 
 correctly, fusibility being dependent not so much on the per- 
 centage of silica as upon the amount of alkali, namely, potash 
 and soda.f Thus the rocks rich in alkaline feldspars are the 
 most fusible. Free quartz exists in most rocks ; and the percent- 
 age of it, which is far from uniform among the members of 
 any particular type, increases the acid character of the rock, so 
 that it becomes a secondary factor in determining fusibility. 
 Similarly iron occurs as an oxide (magnetite) in all rocks, to an 
 insignificant degree in the granites, but in the basalts and gab- 
 bros freely, so as to form an important ingredient, giving them 
 their dark coloring. This large percentage of iron contributes 
 to easy fusibility ; indeed, certain basalts are known to become 
 so limpid that they can be taken up in a spoon attached to the 
 end of a cane.J 
 
 This question of fusibility would be of slight importance 
 were it not for one interesting fact, namely : it has been ob- 
 served in several volcanic regions that lava of intermediate 
 composition, such as andesite, is succeeded by those of the 
 extreme types, namely, the very alkaline or comparatively non- 
 alkaline rocks, such as basalt and rhyolite, respectively. This 
 was the case at the Cripple Creek volcano. It has been in- 
 ferred from these facts that in the earlier stages of volcanic 
 activity the lavas are mingled together underground, and that 
 during the period of eruption the heavier portion separates 
 
 * Manual of Mineralogy and Petrography, p. 437. 
 f Dana, Characteristics of Volcanoes, p. 146. 
 
 J This was actually done in the case of the basaltic lava of Kilauea, in Hawaii. 
 Coan. American Journal of Science. 
 
THE CRIPPLE CREEK VOLCANO. 31 
 
 from the lighter, causing two diverse products to be separately 
 emitted. 
 
 Eventually (it may have been several thousand years after 
 the first manifestation of activity) the volcanic energies became 
 wearied, and lava ceased to appear at the surface. The re- 
 adjustment of the earth's crust, at this particular locality, had 
 been accomplished, and a condition of equilibrium supervened. 
 The lava sank beneath the level of the crater, and, on cooling, 
 plugged up the conduit, as was the case, for instance, at the 
 Kammerbuhl.* The sinking of the lava may have gone further, 
 so that the withdrawal from the upper part of the mountain, 
 formed by the ejections of the volcano, may have caused ex- 
 tensive subsidence and created deep fissures. Such was the 
 case at Kilauea in 1832 and 1840. f Those who are engaged 
 in mining at Cripple Creek are aware of the existence of 
 numerous large cavities underground, particularly in the south- 
 ern part of Bull hill and the northwestern portion of Battle 
 mountain. In the Logan mine the orifice of a very large 
 cavity was recently encountered while sinking the shaft. J The 
 sudden flows of water which have embarrassed some of the 
 mines are due to the unexpected drainage of such openings. 
 It is worthy of note that these especially characterize the 
 trachyte-phonolite and those rock-masses which represent the 
 lavas extruded last. 
 
 After the volcanic energies had declined, there followed a 
 long period of smothered activity, evidenced by geysers and hot 
 springs. Steam continued to escape, but gently. There was 
 none of the violence of the earlier period. Heated water ac- 
 companied the steam, instead of fused rock. The hot lava still 
 existing at greater depth served to give expansive force to the 
 surface waters which found their way, by seepage, through 
 the overlying deposits of volcanic material. The steam and hot 
 water now emitted, at some spots quietly as a thermal spring 
 and elsewhere intermittently as a geyser, probably carried a 
 
 * Judd's Volcanoes, p. 114. See also p. 5 of this paper. 
 
 f Dana's Characteristics of Volcanoes, p. 124. 
 
 J The miners heard the inrush of air caused when they tapped the cavity and 
 promptly left their work, to go to the surface. It is probable that the pumping 
 operations of the neighboring Portland mine had drained the water, which at one 
 time had filled the cavity, leaving it void. 
 
 $ Geyser is an Icelandic word, and means "gusher." A thermal spring which 
 spouts or gushes out above the surface is a geyser. 
 
32 THE CRIPPLE CREEK VOLCANO. 
 
 good deal of mineral matter in solution. A wonderful work is 
 accomplished in this quiet way, because such activities extend 
 over enormous periods of time. Professor Judd has shown 
 that the hot spring at Bath (England), although an apparently 
 unimportant geological agent, brings daily to the surface 
 180,000 gallons of water at a constant temperature of 120 F. 
 This spring was doing its duty at the time of the Roman in- 
 vasion of England, and it is estimated that since that time it has 
 brought up, in solution, enough material to form a good sized 
 volcanic cone.* % 
 
 The Cripple Creek district exhibits abundant evidence of 
 hydrothermal action. This is particularly the case in the 
 northwestern part of the mining area. The breccia of the 
 upper parts of Globe and Ironclad hills, penetrated by the 
 workings of the Deerhorn, Summit, South Park, Plymouth 
 Rock and other mines, is much decomposed, and has a loose, 
 crumbly character. It is seamed to an unusual degree with 
 irregular fractures, lined with secondary minerals, among 
 which crystalline gypsum and amorphous kaolin are the most 
 common. In the Deerhorn shaft there is evidence of a more 
 definite kind. At a depth of 240 feet the shaft cuts into a 
 mass of gypsum, and from that point to the bottom, 575 feet 
 below the surface, it has been sunk in the midst of what 
 appears to be a series of extinct thermal springs. The accom- 
 panying drawing, Fig. 12, will illustrate the occurrence. 
 
 The workings are very extensive in a direction at right- 
 angles to the plane of the section followed by the illustration, 
 and connect with the adjoining mines. Breccia and tuff com- 
 pose the prevailing rock.f No distinct dikes are visible near 
 the Deerhorn shaft; it is probable, judging from the com- 
 position of the breccia at several points, that several intru- 
 sions do exist, but that they have been so shattered in place as 
 to be scarcely distinguishable from the original breccia which 
 surrounds them. At the third level, and at the succeeding 
 levels, there are three distinct narrow-pointed cones of com- 
 
 * Page 21 9 of Volcanoes. 
 
 f The breccia was found by Professor Kemp to contain undoubted fragments 
 of kaolinized granite, decomposed orthoclase being easily recognizable. The 
 breccia of Cripple Creek, although fragmentary andesite predominates, every- 
 where exhibits a scattering of granite particles, which in places become so numer- 
 ous as to give it a truly granitic character. 
 
THE CRIPPLE CREEK VOLCANO. 
 
 33 
 
 FIG 12. 
 
 Deerhorn Shaft 
 
 Gypsum Breccia 
 
 AN EXTINCT THERMAL SPRING, CRJPPLE CREEK. 
 
 pact white gypsum which, at 15 to 25 feet from their apex, 
 graduate into chimney-like masses of breccia cemented by 
 
 3 
 
34 THE CRIPPLE CREEK VOLCANO. 
 
 crystalline gypsum. At the sixth level there is a fourth of 
 these occurrences. Others, which do not happen to have been 
 intercepted by the workings of the mine, may exist in the 
 vicinity. 
 
 Iron pyrites is found in the gypsum ; it occurs as a scattering 
 of coarse crystals in the upper portion, and finely disseminated 
 lower down. The white gypsum carries patches which are 
 stained pink by 'fluorite. The surrounding breccia is every- 
 where traversed by color-bands due to layers of gypsum, man- 
 ganese oxides, and iron ocher. Scattered through the vicinity, 
 but parallel to the group of columns above described, there are 
 patches, as well as seams, of fluorite sand, consisting of parti- 
 cles of crystalline silica stained purple by admixture with fluor- 
 spar. The upper levels also show bands of a white unctuous 
 clay, named " Chinese talc " by the miners. This is pure kao- 
 lin,* derived from the decomposition of the feldspar in the 
 andesite fragments composing the bulk of the breccia. The 
 latter is in a crumbly condition, its character being suggested 
 by the fact that in driving the levels only a pick is needed, the 
 ground requiring no blasting. Beyond the central portion, 
 which has structural lines sympathetic to the arrangement of 
 the columns of gypsum, the breccia is still stained and dis- 
 integrated for a great distance, and in places exhibits sug- 
 gestions of the neighborhood of other thermal conduits. 
 
 There can be no doubt as to the nature of these masses of 
 gypsum. Thermal springs which have become extinguished 
 are marked by just such accumulations of lime, although the 
 carbonate is, under such circumstances, more common than the 
 sulphate. f The flows of hot water encountered in the deep 
 
 * The following is Dr. Hillebrand's analysis, made by him for Prof. Penrose. 
 See page 128 of the Report on "The Geology and Mining Industries of the Cripple 
 Creek District," U. S. Geological Survey, Itith Ann. Rep. Part II. 
 
 Silica, . . , . . . : ' V - 45.08 
 
 Alumina, . . . . J . . . . . 31.83 
 
 Ferric oxide, . . . . '. V . . . . .95 
 
 Lime, . ..... . ... . . 1.76 
 
 Magnesia, . ,"'" . . .,,,.. ' '..'.. . .59 
 
 Potash,. f.' ' "'' J . '"'/ ." ' v ; . ""'". '" ;-.'" ; "' : '. ' '/ "' -' . "' . .14 
 
 Water, . ', ... ' . . . . . . . . 19.96 
 
 100.31 
 f Siliceous deposits characterize geysers. 
 
THE CRIPPLE CREEK VOLCANO. 35 
 
 workings of the Comstock carried a notable percentage of gyp- 
 sum. Last April, while examining certain copper-mines near 
 Hawthorne, in Nevada, the writer came across a group of sim- 
 ilar vents, marking the site of former thermal springs. The 
 conduits, in this case, occurred in lime-shales, and were still 
 open to a considerable depth, as was proved by dropping stones 
 into them. They were surrounded by a compact chimney of 
 carbonate of lime, which had also overspread the enclosing 
 rock. 
 
 Recurring to the conditions observed in the Deerhorn shaft, 
 it would seem that the rising hot waters, in their approach to 
 the surface, were unable to maintain a defined channel through 
 the breccia higher than the level marked by the tops of the 
 cones of gypsum. This might be caused, first, by the fact that 
 the vapors ascending above the subterranean springs disinte- 
 grated the breccia so as to destroy its cohesion, and changed it 
 from a compact rock to loose material. The most potent factor, 
 however, was probably the diffusion of the ascending waters 
 into the drainage of the surface, the effect of which would be 
 encountered at this horizon. The condition of the breccia and 
 the wide area which has undergone disintegration favor this 
 view. 
 
 It is in accord with facts observed in other regions that the 
 vents which permitted the emission of lava-flows should be in 
 one part of the volcanic area (in this case the southern portion) 
 while the escape of hot waters which marked the time when 
 the volcanic energies were waning should have occurred in 
 another part, in this case the northern and northeastern. 
 The lava had healed lines of weakness ; it had cemented the 
 fractures produced by the earlier paroxysmal efforts of the vol- 
 cano ; and therefore the thermal waters found a better chance of 
 exit elsewhere. With the hot waters which found their way to 
 the surface during the closing period of the volcanic cycle there 
 were emanations of gas. Sulphuretted hydrogen was probably 
 emitted, sulphurous acid gas, and, in all likelihood, carbonic 
 acid gas also, although not all of these were to be found at one 
 place or at one time. The volcano had now reached the " sol- 
 fatara" stage.* These acid gases played an important part in 
 
 * "Solfatara" is from the Italian "solfo," meaning sulphur. It is a name 
 given to one of the small volcanoes, near Naples, which is in a condition such 
 as marks the dying out of volcanic activity. 
 
36 THE CRIPPLE CREEK VOLCANO. 
 
 altering the volcanic rocks, and were, possibly, a factor in the 
 process of ore-deposition which was beginning. The vapor of 
 hydrofluoric acid was also among the agencies at work. This 
 is inferred from the large amount of fluorite, the fluoride of 
 calcium, which occurs all over the district, and more especially 
 in the gold-bearing lodes. Fluorite is not common in volcanic 
 regions, although it is found in the lava of Vesuvius. The 
 action of hydrofluoric acid on feldspars containing lime would 
 form fluorite. It would also convert gypsum in a similar way. 
 Fouque has shown that the action of hydrofluoric acid in the 
 liquid state is to decompose, first, uncrystalline silicates or 
 glasses, then feldspar and other acid silicates, then quartz, and 
 lastly, basic silicates. Whether the vapor of hydrofluoric acid 
 would act in the same way is uncertain, although it is possible 
 that in this case quartz might be attacked in preference to the 
 feldspar. This is a matter of interest, because in examining 
 specimens of granite which have been converted into ore (by 
 the addition of gold-bearing tellurides) it is observable that the 
 original quartz of .the granite has been attacked while the 
 orthoclase remains comparatively fresh. 
 
 This last stage of the Cripple Creek volcano is of great 
 importance to the mining geology of the region. It extended 
 over an enormous period, coinciding, roughly speaking, with 
 that which has elapsed since the time to which is ascribed the 
 first evidence of the existence of the human genus, and it 
 afforded, to an unusual degree, those particular conditions which 
 are considered to favor the deposition of precious ores. During 
 this time, also, the breccia, with its finer portions, the tuff, 
 became solidified. The pressure of the overlying masses of 
 lava which at one time covered it, and the chemical solutions, 
 which deposited fresh crystalline substances in the interspaces, 
 converted the scoriaceous material into a compact mass, 
 which eventually became solid rock as we now see it. The 
 cooling of the intrusive bodies of lava caused them to contract, 
 and thus developed lines of weakness along which the ener- 
 gies of the volcanic center developed fractures permitting the 
 subsequent prolonged circulation of underground waters. The 
 readjustment of this particular portion of the earth's exterior, 
 which followed the cessation of volcanic eruptions, and the 
 partial settling of the entire mass forming the Cripple Creek 
 
THE CRIPPLE CREEK VOLCANO. 37 
 
 volcano, must have formed an extensive system of ruptures, 
 which afforded lines of maximum porosity along which the 
 gold-bearing solutions found passage-ways. Thus the hot 
 waters which are supposed to dissolve out the metals from the 
 deep-seated rocks were permitted to ascend toward the surface, 
 where the release from pressure and the lowering of tempera- 
 ture forced them to precipitate their contents. 
 
 The activity of the geysers ceased ; the warmth of the water 
 bubbling from the springs gradually diminished ; and at length 
 the last vestige of the volcanic fires passed away. The moun- 
 tain became as cold as the snow which mantled it each winter, 
 and as still as the darkness enshrouding it nightly. 
 
S OBJECT TO REVISION. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Lodes of Cripple Creek. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 (New Haven Meeting, October, 1902.) 
 
 A. INTRODUCTORY. 
 
 IN a former paper* the writer has described the essential 
 features' of the general geology of the Cripple Creek region. 
 In the present account it is intended to examine into the oc- 
 currence of the ores, the value of which has made this district 
 the most important among existing American gold-fields. The 
 production of Cripple Creek from its discovery, in 1891, to the 
 close of 1901, has reached a valuation of fully $125,000,000. 
 During the past year (1901) the output amounted to $17,285,- 
 470. In 1900 it was $18,174,681. 
 
 The first discoveries, which led to the development of the 
 district, were made in the spring of 1891, but it was not 
 until 1893 that vigorous work was commenced. A great im- 
 petus was then given to the exploration for gold on account 
 of the sudden drop in the market-price of silver, caused by 
 the closing of the Indian mints in the summer of that year. 
 This induced an energetic population from the older silver- 
 mining camps of Colorado to go to the new gold-field, which 
 was then beginning to attract attention. Prospecting, at first, 
 was hindered by the comparative absence of outcrops, due to 
 the fact that the surface of the hills is covered with a consid- 
 erable thickness of shattered rock, resulting from the action of 
 frost at a high altitude ; but so much indiscriminate digging 
 was done that a number of rich veins were uncovered, and this 
 stimulated the search for others. The advanced condition of 
 the mining industry of Colorado offered unusual facilities for 
 exploration and reduction ; progress was therefore rapid, with 
 the result that the district soon achieved great prominence. 
 
 * "The Cripple Creek Volcano," Trans. t xxx., 367-403. It is proper that 
 reference should also be made to the more authoritative monograph of the U. S. 
 Geological Survey, namely, " Geology and Mining Industries of the Cripple 
 Creek District, Colorado," by Whitman Cross and K. A. F. Penrose, Jr. 1895. 
 
Z THE LODES OF CRIPPLE CREEK. 
 
 B. GEOLOGICAL CHARACTER OF THE DISTRICT. 
 
 The geological environment of the gold-bearing veins can be 
 outlined briefly. The district occupies the ground-floor of a 
 volcano, the superstructure of which has been removed by ero- 
 sion. This basal wreck of material erupted during the Tertiary 
 period now survives as a complex of volcanic rocks, tilling the 
 hollows and occupying the plug of a basin which is surrounded 
 by the granite of Pike's Peak. The volcanic area of Cripple 
 Creek occupies about nine square miles, and consists, for the 
 most part, of breccia, in which andesite predominates. Pene- 
 trating the breccia in every direction are numerous dikes, 
 composed of various rocks, those of basalt and phonolite being 
 the most notable, on account of their close association with 
 the occurrence of ore. 
 
 The mine-workings have reached a maximum depth of 1400 
 ft. Added depth appears to have affected the persistence of 
 the ore to the same extent as experience elsewhere would lead 
 one to expect. The veins situated near the edge of the breccia 
 have in several cases been followed downward in their penetra- 
 tion of the underlying granite, and it has been demonstrated that 
 some of the ore-bodies have continued from the upper into the 
 lower geological horizon. The distribution of these ore-bodies 
 offers the same perplexing problems as in other gold-fields. Ex- 
 tensive developments, due to very successful mining, have, how- 
 ever, afforded a great deal of interesting evidence, the consid- 
 eration of which may contribute toward the better understand- 
 ing of the economic geology of the district. 
 
 The mines exhibit examples of a great diversity of lode- 
 structure. This diversity is mainly traceable to the complexity 
 of the enclosing rocks. The variations in ore-occurrence due 
 to this fact explain the vicissitudes which marked the early 
 history of the district, and the recognition of them should pro- 
 mote the success of future exploratory work. 
 
 During the past five years, while examining a dozen of the 
 principal mines, the writer has gathered many examples of 
 vein-structure which are herewith submitted as testimony bear- 
 ing upon the ever-fascinating problem of ore-occurrence. As 
 a poor witness may sometimes furnish a good lawyer with an 
 illuminating bit of evidence, so the writer hopes that this testi- 
 mony may be of service to the geological philosophers who are 
 engaged in the study of ore-deposits. 
 
THE LODES OF CRIPPLE CREEK. 
 
 '+ * 
 
 4- 
 
 4 < *yVV*T* 
 
 
 ; *' + f;*V*] 
 
 4 
 
 f | 
 
 ;^":C%/^tr 
 
 
 
 * 
 
 p 
 
 * * 4 ^ 4 + 4- 
 
 
 ,4.^4 
 
 
 l- 
 f 
 
 "; :!'. '..-. 
 
 4 4. 
 
 
 ^ 
 
 + 
 
 % * l_J^- T-^- 
 
 4- -J 
 
 ^ 
 
 
 
 
 u 
 > 
 
 UJ 
 
 Jj o 
 
 ul 
 
4 THE LODES OF CRIPPLE CREEK. 
 
 C. A TYPE OF LODE-STRUCTURE. 
 
 A small section of a single vein will sometimes typify the 
 lode-structure of an entire region. Such I believe to be the 
 case in the occurrence which is illustrated in Fig. 1. It repre- 
 sents the vertical section of a portion of the Independence vein 
 as it appeared just south of the station at the second level from 
 the No. 1 shaft. The scale indicates that the space covered is 
 about 10 ft. high by 16 ft. wide. The country-rock is the pink, 
 coarsely crystalline Pike's Peak granite ; the vein, A K, L C, 
 appears as a band of iron-stained, decomposed granite along- 
 side of a phonolite dike, A B, C D, which throws out a 
 nearly horizontal tongue, E F, G H, into the rock on the 
 west. This offshoot from the dike is crossed by the vein, and it 
 affects the distribution of the ore. Thus, while the decom- 
 posed gold-bearing granite, constituting the lode, is about 1-1} 
 ft. wide both above and below this intrusion of phonolite, it is 
 broken up at the place of crossing into a few stringers cutting 
 through the phonolite ; so that, while the lode maintains its 
 continuity, it does so with difficulty. An important feature of 
 the section is the evidence obtainable as to the relative age of 
 the phonolite and the joint-planes in the granite. The pho- 
 nolite is, of course, younger than the granite which it pene- 
 trates. But this is not all ; it is also apparent that the joints in 
 the granite are more recent than the dike. Observe how the 
 joint-planes, E F and G H, cut through the protruding sinuosi- 
 ties of the outer edge of the phonolite. It remains to add that 
 there is a distinct division, but no selvage, between the hang- 
 ing-wall, A C, of the vein and the dike which it accompanies, 
 while on the other side, K L, the vein is not marked by any 
 clear line, but graduates, by the lessening of the evidences of 
 decomposition, into the outer granite. The east wall, B D, of 
 the dike exhibits a marked selvage, and it is also accompanied 
 by traces of ore. On the joint-plane, G H, which is nearly 
 horizontal, there is a slight, but evident, selvage. 
 
 The story told by this section is that the phonolite penetrated 
 the granite; that, subsequently, a line of fracture was estab- 
 lished alongside the phonolite ; that this afforded a passage-way 
 for ore-bearing solutions ; that the impregnation of ore was less 
 where the solutions passed through the protruding tongue of 
 phonolite, because there, the rock being closer-grained and 
 
THE LODES OF CRIPPLE CREEK. 
 
 more fissile than the granite, it was broken by a very few de- 
 cided cracks, rather than by an irregular multiple fracturing 
 such as determined the diffused mineralization constituting the 
 lode in the granite; further, it is evident that the jointing of 
 
 FIG. 2 
 
 fv V 
 
 I V y V( PHONOLITE. 
 
 3 
 
 ^4-%] G-R.ANITE 
 GOLD- BSA K IN6-. 
 
 the granite, due to a condition of strain, must have occurred 
 subsequent to the intrusion of the phonolite, because the joints 
 cut through the edges of the phonolite ;* finally, it is rendered 
 
 * Of course it is possible that the cracks through the phonolite are merely the 
 prolongation of the joints, and that this extension of the latter may have been 
 of later origin ; but this is not my interpretation of the evidence as I have seen it. 
 
6 THE LODES OF CRIPPLE CREEK. 
 
 very probable that the jointing of the granite and the fractur- 
 ing now identified with the lode were contemporaneous, both 
 being the result of mechanical stresses connected with the 
 earth-movements which followed the last stages of volcanic 
 activity in the district. 
 
 D. GENERAL CHARACTERISTICS OF THE VEINS. 
 
 The foregoing example will serve as a text for a preliminary 
 statement. The lodes of Cripple Creek are essentially lines of 
 fracture accompanied by a variable width of rock, the constitu- 
 ents of which have undergone replacement by fluorite, quartz, 
 pyrite and other gangue, together with gold-bearing tellurides. 
 The width and distribution of the ore depends upon the extent 
 and character of the fracturing ; the study of the latter is there- 
 fore of vital importance to the miner. Owing to the number 
 of volcanic rocks occurring in the district, the veins differ 
 greatly in appearance ; but this difference is traceable to diverse 
 structural conditions rather than to diversity of origin. In all 
 the lodes which I have examined, the ore is essentially rock in 
 place, however much altered ; the lodes are to be regarded as 
 bands of replacement, rather than the filling of open fissures or 
 crevices ; nor is there any departure from the rule that the 
 lodes were formed during a late period in geological history, 
 for the ore is, in every case, as far as I know, subsequent to the 
 intrusion of the eruptives which penetrate the breccia, itself of 
 late Eocene or early Miocene age. While these eruptives cut 
 across each other and thereby evidence their relative succession 
 in geological time, they do not appear to cut across the ore- 
 veins, which, on the contrary, pursue their course amid varying 
 petrographic conditions, unchecked but not unchanging, for to 
 the changes due to this variable rock-environment we owe the 
 extremely interesting variations in ore-occurrence. 
 
 The lodes have originated from lines of fracture formed sub- 
 sequent to all the members of that volcanic complex which con- 
 stitutes the gold-field. These fractures are the outward mani- 
 festation of lines of weakness, or of such comparative weakness 
 as is the equivalent of least resistance ; therefore, it is not at all 
 surprising that the veins frequently follow the planes of contact 
 between rocks which are unlike in hardness, and especially the 
 very close-grained eruptives when these traverse the coarse- 
 textured breccia. 
 
THE LODES OF CRIPPLE CREEK. 
 
 z 
 
 LJ 
 
 UJ 
 O 
 
 z. 
 
 LJ 
 
 ,->" * ;'-* : ; * '"^-*- *; 
 
 LJ 
 O 
 
 LJ 
 
 in 
 h- 
 
 UJ 
 CD 
 
 Ld 
 
 UJ 
 
8 THE LODES OF CRIPPLE CREEK. 
 
 For this reason phonolite is closely related to the occurrence 
 of ore, so much so, indeed, as to be often confounded with the 
 origin of that ore. The later dikes of basalt are also notably 
 connected with important lodes. It is possible to generalize 
 further and state that the dikes, especially the very numerous 
 dikes of phonolite, spread outward toward the edges of the 
 volcanic area, and, as a consequence, the strike of the principal 
 veins also has a radiated distribution. The latter are dependent 
 in their strike upon structural relations coincident with the 
 dike system, the arrangement of which points to the approxi- 
 mate position of the volcanic vent, or vents, supposed to be 
 situated somewhere in the central portion of the district. 
 
 From these preliminary considerations it is evident that the 
 study of the district, from the point of view of the miner, re- 
 solves itself into the endeavor to understand the structural re- 
 lations of the ore-deposits as affected by the fracturing of the 
 rocks. Questions of origin may be of greater interest, because 
 they appeal to the scientific imagination, but they do not have 
 any direct bearing on the economics of mining. To those who 
 conduct mining operations it is not so much a question of 
 " Where did the gold come from ?" as " What are the condi- 
 tions which determine the distribution of it among the rocks 
 now penetrated by mine-workings?" Therefore, the patient 
 deciphering of complicated systems of fracture will be of more 
 immediate help to the miner than the broad philosophic con- 
 siderations which render the science of ore-deposits so fascinat- 
 ing to all of those who are interested, even indirectly, in 
 mining. 
 
 Before discussing the matter any further it will be well to 
 pass in review more of the evidence afforded by the examina- 
 tion of the lodes as seen underground. For the sake of con- 
 venience, it is considered advisable to divide the lodes accord- 
 ing to their encasing rock, which is also their matrix. 
 
 E. LODES IN GRANITE. 
 
 The granite which surrounds, and partially underlies, the 
 breccia of the volcanic area of Cripple Creek forms a part of 
 the mass of Pike's Peak, the great mountain which overlooks 
 the district from the northeast, and has given its name to the 
 rock. The country near the mines, however, is not the same as 
 
THE LODES OF CRIPPLE CREEK. 
 FIG. 6. 
 
 VKv'^yi; 1 .- 
 
 Anaconda Lode as seen in an Open Cut in 1897. 
 
10 THE LODES OF CRIPPLE CREEK. 
 
 the Pike's Peak granite, orthoclase replacing, to a large extent, 
 the microcline of the typical rock. The Cripple Creek granite 
 may be described as a pink, rather coarsely crystalline rock, 
 the most prominent constituents of which are biotite (black 
 rnica) and orthoclase (feldspar), the latter occurring in large, 
 tabular crystals. The color of the rock is due to that of the 
 orthoclase which has been stained red by iron oxide. Flu- 
 orite occurs sparingly, but it is interesting on account of its 
 association with the ores of the district. In different portions 
 of the district the granite presents variations, the most im- 
 portant of which is a very fine-grained rock that, in the form 
 of dikes, penetrates the coarser variety, and is evidently of 
 more recent date than the basal rock of the region.* 
 
 Fig. 2 illustrates a gold-bearing lode in granite. It repre- 
 sents the heading of the 160-ft. level in the Hallett and Ham- 
 burg claims, near Victor, as seen in April, 1897. The ore ap- 
 pears as an ill-defined band, B B, about 1 ft. wide, which is 
 wholly in granite, but at the same time is only 2 ft. distant from 
 a large phonolite dike, A A. The alteration of the granite, 
 which marks the course of the ore, follows a series of short, 
 overlapping seams, parallel to the line of the dike, and also ex- 
 tends into the surrounding rock along the cross-joints, C C. 
 The width of 2 ft. of granite which separates the vein from the 
 dike exhibits partial alteration along the seams, D D, and car- 
 ries a feeble scattering of ore. The granite under the vein is 
 fresh and unaltered. In the ore-bearing rock the mica is nota- 
 bly absent, the granite is honeycombed by decomposition, and 
 of the two constituent feldspars, oligoclase and orthoclase, 
 the former is kaolinized. Iron pyrite bespatters the gold- 
 bearing portion, and, by its partial oxidation, stains it dark red. 
 
 Fig. 3 exhibits the Independence lode in the Washington 
 claim, which is a portion of the Stratton's Independence prop- 
 erty. The lode, which farther north traverses the breccia and 
 is closely associated with a phonolite dike, is seen here as a 
 band of decomposed granite subdivided equally by a central 
 thread of quartz. The ore is essentially granite. The por- 
 tion A C, D F, is 4 ft. wide, and carries a little over 3 ounces 
 
 * This is discussed by Whitman Cross in "Geology and Mining Industries of 
 the Cripple Creek District, Colorado," U. 8. Geol. Survey, page 23. 
 
THE LODES OF CRIPPLE CREEK. 11 
 
 of gold per ton. The width of 4 ft. which carries gold, and 
 is therefore ore, has no parting or wall separating it from the 
 outer rock, which is granite, and is regarded as waste, but is 
 distinguished from the latter in many ways. The outer granite 
 is fresh and unaltered, exhibiting with great clearness its con- 
 stituent minerals, reddish quartz, black .biotite-mica and pink 
 orthoclase-feldspar. The inner gold-bearing rock is much 
 altered by decomposition and replacement; the orthoclase 
 alone appears to have survived the general destruction; the 
 mica has been removed, and, in its stead, chlorite can be seen 
 in green patches ; the original crystalline quartz is largely 
 gone, and the presence of purple fluorite suggests that hydro- 
 fluoric acid may have been a primary agent in that removal ; 
 secondary hydrous quartz fills many of the interstices between 
 the crystalline constituents of the rock;* in iron-stained cavi- 
 ties free gold can be seen by the aid of a pocket-lens, and the 
 gold is observed to have the dark, lusterless appearance which 
 characterizes it when derived from the oxidation of tellurides. 
 The entire width of this gold-bearing decomposed granite is 
 heavily iron-stained by the oxides resulting from the disintegra- 
 tion of the small crystals of iron pyrite, which can still be 
 seen, in an unaltered condition, scattered throughout the same 
 lode, at lower levels. In the center of the band of ore there is 
 a distinct parting, B E, which is separated from a persistent 
 thread of white quartz, only about a quarter of an inch in 
 width, by a slight selvage of red clay. At a distance, the lode 
 appears as a distinct broad band of iron-stained granite, and it 
 is only by closer examination that the boundaries of it are seen 
 to consist, not of " walls " or of any such evident demarkation, 
 but merely of a transition from decomposed into undecom- 
 posed granite. 
 
 The Independence vein is illustrated again in Fig. 4, which 
 was obtained on the same level as Fig. 3, but 300 ft. farther to 
 the north, where the vein lies against a phonolite dike, A B 
 
 * This description is founded on the examination of hand-specimens by the 
 aid of a pocket-lens. To those who desire to go into the matter further, there is 
 the detailed description of Mr. Lindgren, together with microscopic sections of 
 this very ore (made from specimens which I gave to Mr. Emmons in 1900), to be 
 found in that most important contribution entitled " Metasomatic Processes in 
 Fissure- Veins, " by Waldemar Lindgren, Trans., xxx., 578-692, especially 
 page 655. 
 
12 4 THE LODES OF CRIPPLE CREEK. 
 
 D E. The thread of quartz, shown at B E in Fig. 3, is to be 
 seen again as a larger, but less regular seam, B E, in Fig. 4. In 
 this case it is characterized by cavities, or " vughs," as the 
 miners call them, which gave evidence,* at the time they were 
 first encountered by the workings, that they had served as 
 water-holes along a line of underground circulation. This 
 may be considered as marking the line of the original fracture 
 which determined the course of the lode. In Fig. 3 it was in 
 the center of the ore ; in Fig. 4 it marks the western limit, and 
 separates the ore-bearing granite from the phonolite. The lat- 
 ter is 20 inches wide, and regular. The lode consists, as in the 
 preceding instance, of highly-altered granite, which is richest 
 along the contact with the dike, and shades off eastward (from 
 B E toward C F) along an irregular wavy line, C F, which in 
 no case has any of the characteristics of a " wall " or defined 
 separation between what is gold-bearing ore and what is barren 
 rock. 
 
 These characteristics are repeated in other sections which I 
 have sketched underground. The lodes in the granite are fre- 
 quently remarkable for absence of definition, as was instanced 
 in Fig. 4, this being due to the evenly granular texture of the 
 rock. Within the zone of oxidation the boundaries of a gran- 
 ite lode are made manifest by the red-brown stain, due to the 
 decomposition of iron pyrite ; but below the zone of surface- 
 waters it becomes difficult to distinguish country- rock from ore 
 without frequent assays. When the granite has undergone 
 impregnation it is usually porous, by reason of the removal of 
 the microcline and some of the quartz of the original rock. 
 Whatever biotite, hornblende and epidote it contained are ab- 
 sent from the ore, and their decomposition-product, chlorite, is 
 in evidence. Microscopic sectionsf indicate that secondary 
 valencianite (a form of orthoclase feldspar) and sericite (hy- 
 drous mica) have been formed, and that iron pyrite, fluorite 
 and the tellurides have been deposited within the cavities pro- 
 duced by the removal of parts of the granite, and also along 
 the cracks which traverse the rock. Occasional specimens, ob- 
 tained from the stopes, exhibit these changes on a scale visible 
 
 * By containing water and by being lined with slime. 
 
 f See Lindgren, Trans., xxx., 656, and Genesis of Ore-Deposits, p. 576. 
 
THE LODES OF CRIPPLE CREEK. 18 
 
 without any lens. Thus I possess a piece of ore characterized 
 by large crystals of pinkish feldspar (or orthoclase) and a little 
 silvery mica (muscovite) held together apparently in a cavern- 
 ous mass of quartz, through which bright specks of calaverite 
 are scattered. The quartz contains spots of green, earthy 
 chlorite and a very few minute cubes of fluorite. White quartz, 
 as a distinct veinstone, does not characterize these lodes to the 
 extent usually observable in gold-lodes elsewhere, although 
 secondary quartz is everywhere found penetrating the altered 
 veinstone. Pyrite is also a constant companion of the gold- 
 bearing tellurides, and fluorite is readily to be seen save where, 
 near the surface, it has been decomposed. The occurrence of flu- 
 orite has suggested many theories, but the fact that it forms an 
 original constituent of the granite of the Pike's Peak region 
 and the prevalence, in the same neighborhood, of such fluorine- 
 bearing minerals as cryolite and topaz,* renders it dangerous to 
 draw inferences connecting it with the ore-forming agencies. 
 There is the appearance of probability about the idea that the 
 secondary fluorite of the lodes was derived by the circulating 
 waters from the granite of a lower horizon, and it may be men- 
 tioned that Fouque showed that hydrofluoric acid in a liquid 
 state has a notable effect on silica and silicates by first de- 
 composing the uncrystallized silicates, or glasses, and then act- 
 ing similarly on feldspars and other acid silicates, then on 
 quartz, and lastly upon the basic silicates. Whether hydroflu- 
 oric vapor acts similarly is an open question. Under such cir- 
 cumstances, quartz might be attacked before feldspar. 
 
 F. VEINS IN ANDESITE AND ANDESITE BRECCIA. 
 
 The andesite of Cripple Creek is usually an augite-mica- 
 andesite. It is distinguished by having apatite as one of its 
 constituent minerals. Although this andesite forms the prin- 
 cipal element of the breccia, the latter is notably irregular in- 
 its composition. Phonolite is sometimes locally predominant, 
 and near the edge of the volcanic area the breccia contains a 
 large proportion of fragments of granite. The breccia, since 
 
 * Florissant and the Pike's Peak region generally are celebrated for specimens 
 of topaz. W. S. Stratton, the discoverer and former owner of the Independence 
 mine, was prospecting for cryolite, as a source of aluminum, just previous to his 
 first trip to Cripple Creek. 
 
14 THE LODES OF CRIPPLE CREEK. 
 
 it was laid down as a product of violently explosive volcanic 
 eruption, has become decomposed and cemented. According 
 to Whitman Cross, the decomposition has led to the " total de- 
 struction of the dark silicates," such as the augite, hornblende 
 and biotite present in the original fragments, and in the re- 
 moval, by leaching, of the compounds resulting from this de- 
 composition.* The result has been to change the breccia from 
 dark crumbling material into a bleached compact mass which, 
 in process of time, by reason of pressure and waters contain- 
 ing kaolin, silica and other cementing substances, has become 
 consolidated into a hard, massive rock. In the vicinity of the 
 lodes the effects of siliceous solutions are rendered apparent 
 by the impregnation of quartz to such a degree as to obscure 
 the original fragmentary nature of the rock and make the 
 finer-grained breccia, or tuft', resemble phonolite in texture 
 and appearance. The variations in the andesite and andesite- 
 breccia are responsible for corresponding changes of lode- 
 structure, as will be presently illustrated. 
 
 Fig. 6 is a photograph of the Anaconda lode, as seen in an 
 open-cut, in July, 1897. The lode at this place forms a part of 
 an andesite dike traversing the breccia. The dike exhibits a 
 multiplication of fractures parallel to its walls, and along these 
 lines of cleavage there occur seams of quartz and fluorite car- 
 rying tellurides.f In the surf ace- workings, the gold liberated 
 from the tellurides occurred pseudomorphic after sylvanite, 
 distributed in yellow patches amid purple fluorite, affording 
 specimens of great beauty .J 
 
 When, as rarely happens at Cripple Creek, the lode consists 
 of massive ore notably separated from its encasing rock, it will 
 be found that such definition of structure is due to the presence 
 of fluorite and secondary quartz which have so filled up the 
 interstices of the decomposed breccia as quite to obscure its 
 original character. Fig. 7 represents the main lode of the 
 Gold King mine, in Poverty Gulch. At the time the drawing 
 
 * "Geology and Mining Industries of the Cripple Creek District, Colorado," 
 U. S. Geol. Survey, page 52. 
 
 f The general characteristics of the ores of this district have been separately 
 described. " The Telluride Ores of Cripple Creek and Kalgoorlie," by T. A. 
 Rickard, Trans., xxx., 708-718. 
 
 t See " Further Notes on Cripple Creek Ores," by Eichard Pearce, Proc. Colo. 
 Scientific Society, vol. v., pp. 15-18. 
 
THE LODES OF CRIPPLE CREEK. 
 FiG. 7 
 
 15 
 
 ^'^ 
 
 v - : < * - 
 
 . 
 
 -'' 
 
 BRECCIA 
 
16 THE LODES OF CRIPPLE CREEK. 
 
 was made the stopes had a maximum width of 12 to 18 ft. 
 The rock, owing to partial oxidation, seemed, at first glance, to 
 be structureless and homogeneous, but on closer investigation, 
 prompted by contradictory assays, it was found that in the 
 middle of the section afforded by the stopes, which were (for- 
 tunately for the purpose of observation) unencumbered with 
 timbering, there was to be seen a compact dark band, A B- 
 O D, from which small seams, E E, went out, almost at right 
 angles, into the surrounding breccia. This band, which was 
 the vein proper, also consisted of breccia, but so impregnated 
 with purple fluorite and so interpenetrated by secondary quartz 
 as to hide the fact. Throughout the massive vein-stuff fine 
 iron pyrite was scattered, and with the pyrite were crystals of 
 calaverite, rendering it very rich. At intervals, small cavities 
 lined with crystalline quartz occurred, as is indicated at H, H, 
 in Fig. 7. In these cavities occurred crystals of native gold 
 pseudomorphic after calaverite. Owing to their dull, rusty 
 exterior, they looked like bits of rotten wood, and it required 
 close observation, especially underground, to detect them. 
 When scratched, they gave instant testimony of their precious 
 nature. Minute stringers of ore, rendered noticeable by the 
 color of the fiuorite, followed the cross-fractures or joints in the 
 surrounding breccia, and, as delicate threads, accompanied the 
 central vein, A B-C D, the boundaries of which were further 
 marked by a granular selvage along A C. 
 
 Fig. 8 is very characteristic of Cripple Creek veins in brec- 
 cia. It represents the breast of a level following one of the 
 branches of the Bobtail lode, in the Independence mine, on 
 Battle mountain. The Bobtail lode itself is similar, but its 
 true structure is less evident on account of a more diffused im- 
 pregnation of ore. The oxidation of the pyrite accompanying 
 gold-bearing tell u rides marks the course of the ore-streaks, 
 A B and C D. They look, at a distance, like mere stains ; but 
 closer observation discloses the. fact that they are partings 
 along the lines of fracture in the breccia, each of which forms 
 the center of a narrow band of oxidized pyrite and very minute, 
 bright specks of calaverite. The latter is seen, under the mag- 
 nifying glass, to be in process of decomposition, the oxidation 
 of the tellurium of the telluride in the presence of decompos- 
 ing pyrite having resulted in the formation of the tellurite of 
 
THE LODES OF CRIPPLE CREEK. 
 
 IMPREGNATION ALONG PARALLEL. FRACTURES 
 
 iron* and the liberation of the gold in a brown amorphous 
 condition, resembling yellow paint which has become tarnished. 
 
 * This alteration product has a definite chemical composition, as has been de- 
 termined by F. C. Knight. See "A Suspected New Mineral from Cripple 
 Creek," Proceedings of the Colorado Scientific Society, vol. v. , pp. 66-7.1, October 1, 
 1894. Mr. Knight's analysis gave a percentage of Fe.,0,, 32.72; TeO.,, 65.45 ; and 
 H 2 O, 1.83. The physical characteristics ascertained were, a light-brown color, 
 a dull luster, a brilliant and uneven fracture, a hardness between 3 and 4, and a 
 bright yellow streak. 
 
18 THE LODES OF CRIPPLE CREEK. 
 
 The tributary streaks, along the cross-joints of the breccia, are 
 also gold-bearing for a short distance away from A B and C D. 
 
 Such parallel partings as have been shown in Fig. 8 are 
 sometimes so multiplied as to become zones of sheeting. An 
 example is exhibited in Fig. 9, which represents a lode in the 
 Moon- Anchor mine. This type of ore-occurrence is thoroughly 
 characteristic of the mines' in that part of the district known as 
 Gold Hill. The breccia is fine-grained. The partings are 
 about a quarter of an inch apart. They are followed by minute 
 seams of red, gritty, clay in which the tellurides can be distin- 
 guished. The individual seams are united by transverse im- 
 pregnations which collectively make a pocket or small body of 
 ore, in which it is not unusual to encounter patches consisting 
 of an almost solid aggregate of crystalline calaverite and kren- 
 nerite.* This sheeted structure dies out into the enclosing 
 country-rock by the process of a gradual widening of the space 
 intervening between each successive parting. 
 
 Fig. 10 represents the Emerson vein at the fourth level of 
 the Independence mine. Here, also, the country is andesite- 
 breccia. A central thread, B E, of fluorite and quartz, is fol- 
 lowed by a band, A C, D F, about 3 ft. in width, of decomposed 
 rock, which is gold-bearing, and therefore regarded as a lode. 
 This lode appears as a band of bleached rock amid the dark- 
 gray breccia. It is marked by thin veinlets of quartz, and is 
 sparingly honeycombed with small, spongy cavities, containing 
 iron pyrite and fluorite. The ore has no defined boundaries, 
 but in the space from A to C and D to F it averages 2J oz. of 
 gold per ton. 
 
 The breccia and tuff exhibit the effects of the thermal waters 
 which have penetrated them during the quiescent stage of the 
 volcano. Kaolinization of the feldspars was the most evident 
 result; the dark silicates also are entirely gone, and are re- 
 placed by white mica.f During the subsequent period, when 
 the ore-deposits were in process of formation, these decomposed 
 fragmentary rocks, already partially cemented by their kaolini- 
 zation, became further consolidated by siliceous solutions, so as 
 
 * Krehnerite is a telluride of gold, approximating calaverite as regards compo- 
 sition, but differing from the latter in possessing a perfect cleavage. It was named 
 after Professor J. A. Krenner, of Buda-Pesth. 
 
 t As observed both by Lindgren and by Cross. 
 
THE LODES OF CRIPPLE CREEK. 
 
 19 
 
 to be changed into a compact hard rock. Underground, near 
 the veins, by reason of the bleaching, due to decomposition, the 
 
 FIG. 9 
 
 ORE STREAKS 
 
 ORE ALONG SHEETED ZONE 
 
 breccia has the mottled look which the miners recognize by the 
 term x "porphyry." As in the case of the granite, secondary 
 minerals are readily found wherever the breccia has been 
 
20 THE LODES OF CRIPPLE CREEK. 
 
 changed into ore and the groundmass of the rock is seen to 
 have undergone substitution by fluorite and pyrite. The 
 former enters into the groundmass so thoroughly, sometimes, 
 as to make it a purple rock spotted with bits of bleached ande- 
 site. It is a feature of the breccia that the ground-mass of it 
 has undergone mineralization more extensively than the rock- 
 fragments which it contains, an observation which illustrates 
 the selective action of the circulating waters. As a conse- 
 quence, even when it is changed into ore, the included pieces 
 of andesite are conspicuous, and are often edged with the ore- 
 forming minerals, such as pyrite, fluorite and the tellurides. 
 However, the most important change which the breccia has 
 undergone, in the vicinity of the lode-fractures, is its silicifica- 
 tion by impregnation with quartz. This is not so apparent as 
 would be imagined, because it does not occur in the form of 
 bands of white quartz or dark hornstone, but rather as an ill- 
 defined width following the dominant lines of fracture. For this 
 reason the ore is often harder than the country-rock, and the 
 workings on the lode require less timbering than the cross-cuts. 
 
 G. VEINS IN PHONOLITE. 
 
 Phonolite is in many respects the most characteristic rock 
 of the gold-field because of the comparative rarity, elsewhere,, 
 of this species of eruptive, and its marked association with the 
 occurrence of ore in this particular mining district. The essen- 
 tial constituents of phonolite are nepheline and that glassy 
 variety of feldspar termed sanidine. Sodalite, noseaii, and a 
 variety of augite called aegirine, are common to the Cripple 
 Creek phonolite, which, typically, appears as a dull greenish- 
 gray, dense, very hard rock, distinguished from the other erup- 
 tives in the district by a schistose structure* that gives it a 
 sherd-like fracture. In the vicinity of the lodes the greenish 
 tint (due to augite and allied minerals) has been obliterated by 
 bleaching, and a speckled or porphyritic appearance is given 
 by white spots of decomposed nosean.f 
 
 * Due, according to Whitman Cross, to the fluidal arrangement of the tabular 
 feldspars. Op. cit, p. 33. 
 
 f This is especially a characteristic of the so-called Independence dike, as seen 
 at the third and fourth levels of that mine. Professor Judd, F.R.S., from speci 
 mens which I sent to him, labelled this rock distinctively a "nosean phonolite." 
 For further discussion of the varieties of phonolite occurring in the region, the 
 reader must refer to Dr. Whitman Cross's interesting descriptions in the "Geol- 
 ogy and Mining Industries of the Cripple Creek District, Colorado," pp. 34 to 41. 
 
THE LODES OF CRIPPLE CREEK. 
 
 21 
 
 Phone-lite is normally a fine-grained close-textured rock, and 
 for this reason the alteration which it has undergone, wherever 
 it has been in the passage-way of the ore-depositing agencies, 
 
 FIG. 10 
 
 B 
 
 Sill' 
 
 
 IMPREGNATION F0LLCW//VG- 4 SING-LE 
 
 is rendered more striking. The Independence dike, which ac- 
 companies a very rich vein, has been so corroded by the solu- 
 tions as to be a spongy-looking porphyritic rock, especially 
 
22 THE LODES OF CRIPPLE CREEK. 
 
 wherever it happens to have lain in the path of the ore-bearing 
 solutions which found a way along the vein-fracture. Where nor 
 thus altered by impregnation, the phonolite is often so cleaved 
 by cracks parallel to its walls, and to those of the accompany- 
 ing lode, as to resemble a shale. At such places it is usually 
 mineralized by the occurrence of pyrite and tellurides along 
 the faces of the cracks. 
 
 The phonolite occurs not only within the central mass of 
 breccia, but also outside the immediate boundaries of the vol- 
 canic area, penetrating the granite in dikes and in large, irreg- 
 ular, intrusive masses, one of which forms Mt. Pisgah, so cele- 
 brated in. connection with the early history of the Pike's Peak 
 region.* 
 
 In the distribution of ore, phonolite plays an important part, 
 as the sequel will show. It has already appeared in Fig. 4, but 
 not in so direct a relation as, for instance, in Figs. 5 and 11, 
 now to be described. 
 
 Fig. 11 is especially interesting when taken in connection 
 with Figs. 3, 4 and 5, because it represents the same vein amid 
 a different geological environment. The dike in Fig. 4 is the 
 same as the one, B C-E F, in this drawing, while the body of 
 phonolite to the left is a tongue from a large mass of brecciated 
 phonolite occurring in this part of the mine. The feature to 
 which it is desired to draw attention is the distribution of ore 
 at this point. The dike, B C-E F, is the traversing breccia. 
 The main ore-streak consists of the width of breccia, 26 inches 
 across, separating the phonolite at B E from that at A D. There 
 is some ore also in the phonolite dike, especially along C F, 
 where it is so shattered as to resemble a shale. Threads of ore 
 also occur along the other cleavage-planes in the phonolite, 
 and are (observe G G) widely distributed through the breccia 
 to the east, so as to form a large mass of comparatively low- 
 grade ore. By way of summary, it may be said that the ore is 
 scattered through the breccia and is concentrated near the 
 edge of the phonolite, occurring in the body of the latter only 
 where it happens to be shattered. 
 
 In Fig. 5 the Independence vein is again illustrated, as it 
 
 * The Mt. Pisgah story is told in my earlier paper, "The Cripple Creek Gold- 
 field." Proceedings of the Institution of Mining and Metallurgy, London. Vol. 
 viii., pp. 50-51. 
 
THE LODES OF CRIPPLE CREEK. 
 
 23 
 
 appeared in the raise between the 800-ft. and the 700-ft. levels, 
 in June, 1899. The same dike of phonolite, E F-G H, having 
 
 .P. 
 
 BRECCIA 
 
 -PHONOLITE: 
 
 here a width of from 18 to 20 inches, occupies the center of the 
 band of gold-bearing granite, A C-B D, which is the lode. 
 
24 THE LODES OF CRIPPLE CREEK. 
 
 When sampling the ore, previous to shipment, it was found 
 that the dike only yielded fines or " screenings," indicating that 
 the fine particles, which came oft' the cleavage-planes, carried 
 whatever gold there was in the phonolite. In the case of the 
 granite, on the contrary, the bulk-ore was the best. The lode 
 extends from A to C ; the left-hand portion is about 2 ft. wide, 
 it is traversed by streaks of fluorite, and is richest along the 
 contact with the dike. This is also true of the right-hand por- 
 tion, which is 2J ft. wide and similar in character. The richest 
 parts follow the dark streaks composed of purple fluorite asso- 
 ciated with iron pyrite, accompanied by the tellurides, sylvan- 
 ite and calaverite.* The walls, A A and B B, are clean and 
 defined, with a slight selvage. The outer rock is a fresh pink 
 granite, the inner lode-granite being kaolinized and otherwise 
 altered. 
 
 Fig. 12 was obtained at the fourth level of the Independence 
 mine, at a place where a part of the Bobtail vein, in its north- 
 ward course, penetrates a mass of phonolite, which, apparently, 
 is only a local enlargement of another dike crossing the breccia 
 at a slight angle with the vein. The main streak of ore, even 
 at this point, is in breccia, so that it is only the enlargement of 
 the Bobtail lode, 5 to 6 ft. wide, which is considered to reach 
 into the phonolite. The planes of fracture are well-marked. 
 Where the ore occurs, the rock is sheeted along lines which 
 are parallel to the lode, and accompanying these fractures there 
 are found small threads of extremely rich material. That 
 marked A A is the largest ; it is only from a quarter to half 
 an inch thick, and consists of little crystals of iron pyrite, 
 which, by reason of their partial oxidation, give the ore-streak 
 a dull-red color, and render very distinct its passage through 
 the light-gray rock. Tellurides accompany the pyrite, and are 
 the cause of the high gold-contents of the ore. The other 
 streaks are similar, though smaller. The surrounding phono- 
 lite is peppered over with minute cubes of purple fluorite, 
 which darken it. t Many of the planes of fracture are lined 
 with the same material. The whole mass, from A A, and 
 across C C, for a width of 6 ft., assayed 3 to 4 ounces of gold 
 per ton. 
 
 * And especially a massive granular telluride, found, by Mr. W. E. Ford, to 
 be a variety which, as regards composition, is intermediate between calaverite and 
 sylvanite. 
 
THE LODES OF CRIPPLE CREEK. 
 
 25 
 
 H. VEINS IN BASALT, TRACHYTIC PHONOLITE, ETC. 
 
 Numerous dikes of nepheline basalt, the last product of the 
 Cripple Creek volcano, occur in the district, especially in its 
 southwestern portion. The Raven, Elkton, Anna Lee, Black 
 
 PIG. 12 
 
 RICH -STKEAKS \ M 
 
 Diamond, Moose, Bertha, Trail and other mines contain lodes 
 which are an integral portion of such dikes. They are usually 
 much decomposed, hy reason of their basic constitution, and 
 do not make any showing at the surface. Of the several lodes 
 associated with these basalt dikes, the Elkton is the most inter- 
 
26 THE LODES OF CRIPPLE CREEK. 
 
 eating. A characteristic section is given in Fig. 13, which 
 illustrates this lode as seen in the stopes above the fifth level, 
 in May, 1899. The dike is nearly 4 ft. wide, from A C to 
 B D, and traverses the andesitic breccia of Raven Hill. It 
 shows a distinct lamination parallel to the walls. This is very 
 strong along the outer edges of the basalt, where it is also 
 bleached and decomposed. The central portion of the dike 
 appears as a hard, dark-gray mottled rock, marked by evident 
 cross-jointing. The dike is nearly vertical, inclining slightly 
 to the east. The cross-joints dip northward at an angle of 
 about 20, and facilitate stoping. The basalt exhibits the 
 effects of mechanical stress by its lamination, which is suffi- 
 ciently pronounced in places to give the. rock the character of 
 shale and to render mining dangerous. 
 
 Evidences of chemical alteration are apparent, and they co- 
 incide with the occurrence of ore. The latter usually follows 
 the west wall, but occasionally it is found on both walls, and 
 more rarely in a scattering through the mass of the dike. 
 The total width of ore in these particular stopes averaged 
 about 18 inches. 
 
 A remarkable feature of the section is the inclusion, within 
 the dike, of fragments of granite. The largest of these (at Q) is 
 4 inches wide. In the neighboring stopes such inclusions were 
 frequently seen. This suggests the vicinity of the basal granite. 
 In fact, the level above which this drawing was made leaves 
 the breccia and enters the outer granite at a point only 850 ft. 
 from the place here illustrated. At an intermediate point, 
 where the Elkton dike is not ore-bearing, I secured the section 
 shown in Fig. 15 ; here larger fragments of granite are in- 
 cluded within the basalt, and the breccia itself is seen to con- 
 tain numerous fragments of the older rock. 
 
 In Fig. 13, which is a characteristic section of the lode, the 
 main streak of ore is seen to follow the western boundary of 
 the dike, and to include the rock on either side of that line, so 
 as to obscure it. There is no parting or selvage to mark the 
 line of division between the basalt and the breccia ; that is, it 
 is, as a miner would express it, " a frozen contact." The ore 
 spreads across into both. Both alike exhibit the destruction of 
 their original soluble constituents and the replacement by 
 veinstone, especially fluorite. The breccia is bleached by the 
 
THE LODES OF CRIPPLE CREEK. 
 
 27 
 
 kaolinization of the feldspar, and is honeycombed with cavi- 
 ties which contain water-quartz in various forms, especially 
 hyalite. The telluricles, sylvanite and calaverite, are scattered 
 through this decomposed hreccia and extend into the adjoin- 
 
 
 S'' 1 - ' ^.:- 1 ' 
 
 
 ;- 
 
 %f?$.~yiW$-*Z& ^^ .' r?;**X*.?*?::.; \*$i 
 
 ; *v. p^pfe^::? ^^if^sS^I 
 
 ,- * !.. \ v" .- * .->- 17, -v-* -i^.^ . >'<> '--. -?;V_.-__J >- 
 
 : -^^^~?^ ; C j"^- - ^x^H-r.;.^ -. -'?s 
 
 D 
 
 '^^^^^^ s 
 
 %'- < v< vr v ^^*<r-< v r^^M*** i r<"/ > 
 
 'ai^iiS&sa; IM 
 
 ^v.^ /D 
 
 ing basalt. This latter is also bleached to a dull gray, and is 
 seamed with ore along the faces of the cleavages. Although 
 neither the walls of the dike nor the ore-streaks themselves are 
 indicated by selvages, it is noteworthy that several very dis- 
 tinct partings, followed by clay-seams, traverse the basalt in 
 
28 
 
 THE LODES OF CRIPPLE CREEK. 
 
 lines parallel to its strike. They are shown at G M, H BT, 
 K O and L. P. 
 
 This section presents another interesting feature. It will be 
 noticed that on the east side the breccia is brecciated ; that is, 
 the fragmentary rock has been broken again into fragments by 
 a later movement which took place along the course of the 
 dike. It is likely that the other side was similarly affected, but 
 
 FIG. 15 
 
 ELKTON DIKE 
 
 I could not determine the fact with certainty, owing to the de- 
 composition of the rock and the deposition of ore. That this 
 movement bears some relation to the period of ore-formation 
 is most likely ; that it occurred subsequent to the complete 
 consolidation of the dike is rendered certain by another sec- 
 tion, shown in Fig. 16, obtained in a neighboring level of the 
 same mine. Here a lateral offshoot, A B, of basalt is seen to 
 
THE LODES OF CRIPPLE CREEK. 
 
 29 
 
 be clearly broken by vertical movement. The central portion 
 of the dike is dark green, with secondary chlorite, and is 
 speckled by feldspar phenocrysts. The dike, C D E F, only 11 
 inches wide at this point, also exhibits a banded structure along 
 the sides, suggesting a differentiation between the core and its 
 
 FK;. 16 
 
 a:,. 
 
 ANDESITE 
 
 ELKTON DIKE 
 
 GR/\NtT 
 
 ^dges, due to a less complete crystalline development, conse- 
 quent upon rapid cooling at the time of intrusion into the 
 breccia. The latter is seen to contain numerous fragments of 
 granite, for this section, also, was secured at a distance of 500 
 feet only from the granite rim. 
 
30 
 
 THE LODES OF CRIPPLE CREEK. 
 
 iiiM 
 
 il 
 
 #;vVi::;#- 
 
 
 i;SS(* 
 
 ^^Kfe-vv 
 
 K^^&SiS} 
 
 &&;&?:& 
 
 g*?|l%l 
 
 Ilil 
 
 Another section is illus- 
 trated in Fig. 14, obtained in 
 the same stopes as Fig. 13, 
 but about 50 ft. farther north. 
 The dike, A C-F E, is 3 ft. 
 10 inches wide. It has a very 
 distinctly laminated structure, 
 and in places it breaks like 
 shale.. It is spotted with vesic- 
 ular cavities which are lined 
 with zeolites and hydrous 
 quartz. The ore occurs along 
 each wall of the basalt, spread- 
 ing over into the encasing 
 breccia. No selvage divides 
 the dike from the outer rock, 
 but the bands of decom- 
 posed ore-bearing basalt, A 
 B-C D, and L F-M E, are 
 separated from the central 
 mass of the dike by distinct 
 clay-partings, B D and L M. 
 The ore-bearing edges of the 
 dike are rich in tellurides. 
 That part of the ore-streak 
 which consists of mineralized 
 breccia, F H-E G, appears as 
 a kaolinized rock darkened 
 by spots and streaks of purple 
 fluorite. It is from 2 to 6 
 inches wide, and is fairly well 
 distinguished from the outer 
 gray breccia by the contrast of 
 color. The enclosing rock is a 
 fairly coarse breccia, marked 
 by sintery spots, due to altera- 
 tion. These are frequently 
 ore-bearing, by reason of tel- 
 lurides. The slips or parallel 
 fractures, S S, also carry a 
 little ore upon their faces, and 
 
THE LODES OF CRIPPLE CREEK. 31 
 
 permit the rock to be mined at a profit, because it yields 
 " screenings " or fines, which are rich enough to be sent to the 
 smelter. 
 
 In Fig. 17 there is given a characterization of the chief fea- 
 tures of the Elkton lode-structure. The vein is remarkably 
 straight ; in the breccia it appears as one or more small frac- 
 tures carrying tellurides, accompanied by chlorite ; when the 
 vein encounters the basalt dike, it follows the latter as long as 
 the basalt maintains a direction similar to the strike of the 
 vein ; when the basalt is crossed by a later dike of phonolite, 
 the vein-fractures persist across the phonolite, and spread so as 
 to make a large width of gold-bearing rock. 
 
 The trachytic phonolite of Cripple Creek occurs in large 
 intrusive masses, which are penetrated by later dikes of phono- 
 lite and basalt. It has a decided porphyritic habit by reason 
 of the occurrence of large orthoclase crystals in a dense ground- 
 mass. The workings of the Legal Tender (or Golden Cycle) 
 property are in this rock, and afford examples of lode-structure. 
 In Figs. 18 and 19 the Harrison vein is illustrated as it is seen 
 in this mine. 
 
 The Harrison vein consists of a band of shattered coun- 
 try in the trachytic phonolite ; the center of it is marked by a 
 leader, usually very rich, bordered by fractured rock having a 
 very variable width. This leader is shown at B E in Fig. 18 
 and A B in Fig. 19. 
 
 In the first example, secured just above the 6th level, B E 
 appeared underground as a streak of crushed rock, 3 to 4 inches 
 wide, and dark-red in color by reason of the oxidation of pyrite. 
 The band of brecciated and bleached rock on the hanging-wall 
 side, from A to B and from E to D, contained numerous little 
 threads and spots of pyrite, accompanied by just sufficient 
 gold tellurides to make it low-grade ore. The corresponding 
 band on the foot-wall, from B to C and from E to F, was less 
 decomposed and exhibited more clearly a defined system of 
 fractures, the latter being lined with fine-grained iron pyrite. 
 In Fig. 19, A B appeared underground as a seam, 1 to 1 J 
 inches wide, of white, gritty mud, very rich in gold. The hang- 
 ing-wall, from A to C and from B to D, is brecciated and 
 ore-bearing, as is the corresponding band, A E-B F, on the 
 foot-wall ; but the latter, being less fractured, is also less rich 
 than the other side of the lode. 
 
32 
 
 THE LODES OF CRIPPLE CREEK. 
 Fro. 18 
 
 + X + X 
 
 -h X + X U- ' * . | , 
 
 ^, ' I: 
 
 X f- X f- *.'' - T-/J1 
 
 ^- x */ ./ .'-.-I 
 
 t- >. . 
 
 
 
 
 TRACHrTE PORPHYRY 
 
 VEIN 
 
 The widest ore found on the Harrison vein is found at 
 places where spurs or subordinate veins joined the main lode. 
 
THE LODES OF CRIPPLE CREEK. 
 FIG. 19 
 
 33 
 
 X +- X 4- x-t-X4-X/v 
 
 t X 4- X4-X4-X 4-/*;- . 
 t-X 4- * 4- x. 4- X 
 
 X 4- X 4- X 4- X 4- 
 X 4- X 4- X, 4- X 4- X \ X/, 
 
 4* X "t~ ' - T- '-> i "/x 
 X -f- X H- X 4- X/ 
 X^X 4-X4-X/^^ X /, 
 
 4- x -f- x -I- x 4-/.\x / /* 
 
 4- X +- x 4- X f / >0 /, \ 
 
 X 4- X 1" X t" 
 
 X X- *- X 
 
 f-X--/X -f- X4-X 
 X 1- X 
 
 .14- X -H X.4- A4-Xf- 
 
 ORE 
 
 H/\RKiSON VEIN. No.*/ 
 
 This gives the ore-bodies a disconnected character, a series of 
 linked enlargements, rather than the appearance of a persistent 
 
THE LODES OF CRIPPLE CREEK. 
 
 ore-streak; when the ore-body narrows, the line of the lode 
 becomes indistinct, being indicated merely by a group of irreg- 
 ular fractures scarcely different from the fractures to be seen in 
 the crosscuts, and not recognized as " veins " simply because 
 they do not carry pay-ore. 
 
 FIG. 30 
 
 
 r.f^- W 
 
 tLzili} PMOIX/OLITE - y C-OCD-BE4RING 
 
 Vein Traversing a Sheet of Phonolite. 
 
 I. VEIN CROSSING A SHEET OF PHONOLITE. 
 
 The occurrence recorded in Fig. 20 represents the Orizaba 
 vein, on Beacon Hill, as seen in September, 1899. The coun- 
 try is granite, which, in this part of the district, is penetrated 
 by several sheets and intrusive cores of phonolite. The Orizaba 
 vein cuts through at least two of these flat intrusions, and in 
 doing so presents several interesting features. Fig. 21 illus- 
 trates the relation between the geological structure and the 
 
THE LODES OF CRIPPLE CREEK. 
 
 35 
 
 mine-workings at 220 ft, below the surface. The phonolite is 
 from 9 to 11 ft. thick, dipping flatly both northward and west- 
 ward. At the south winze the phonolite is cut at a point 4 
 ft. down, and is found to extend thence to a depth of 13 J ft. 
 The remainder of the winze, to the bottom, at 23f ft., is in 
 granite. The north winze, which is 77 ft. distant from the 
 other, penetrates phonolite at 13J ft., and strikes granite again 
 at the bottom, 23 ft. down. The phonolite is faulted about 14 
 in., B to C and D to E, Fig. 20, by the fracture which marks 
 the line, A B D F, of the vein. In the granite the vein ap- 
 pears as a narrow seam, but in its passage through the phono- 
 lite it opens out and forms a series of cavities which are lined 
 with long prismatic crystals of sylvanite, encrusted with quartz, 
 affording specimens of great beauty, and, of course, of extra- 
 ordinary richness. The tellurides also impregnate the rock 
 encasing the fracture. 
 
 FlO. 21 
 Leuel 
 
 Granite 
 
 phon 
 
 olite 
 
 Sheet 
 
 Granite 
 
 This shows the Relation of the Phonolite Sheet (Fig. 20) to the Workings. 
 
 In crossing the phonolite, the lode-fracture straightens up ; 
 in leaving it, and passing into the granite again, it flattens. 
 While traversing the 9 to 10-ft. sheet of phonolite, and for 
 a farther distance of 15 to 20 ft. into the granite above the 
 phonolite, the vein carries very rich ore, forming a flat body, 
 the pitch of which conforms to the dip of the phonolite. 
 Farther up, the vein becomes impoverished, until, at a point 85 
 ft. above the 220-ft. level, it encounters another flat sheet of 
 phonolite, characterized by a repetition of the conditions just 
 described. In the stopes above the 220-ft. level the granite is 
 mined not only for the 4 or 5 inches of vein proper, but also 
 for as much as 5 or 6 ft. into the hanging-wall, which is tra- 
 versed by telluride threads, parallel to the line of the vein. In 
 the phonolite the vein is characterized by " vughs " or cavities, 
 2 to 8 inches wide, yielding an average of about 5 inches of rich 
 
36 THE LODES OF CRIPPLE CREEK. 
 
 ore. This rich ore does not continue downward into the 
 granite under the phonolite ; the vein thins out, becoming a 
 mere thread amid a series of parallel seams, which give the 
 granite a schistose character for a width of one foot. 
 
 J. GENERAL OBSERVATIONS. 
 
 The occurrence of ore in the Cripple Creek district is inti 
 mately related to the distribution of fractures. As a rule, the 
 veins, in their strike and dip, exhibit an evident sympathy with 
 the dikes, more particularly those of phonolite, which are also 
 the most numerous. It is true that the locality of Bull Hill is 
 crowded with a very large number of veins which appear to be 
 independent of dikes, but it is a fact, proved by the experience 
 of mining in the district, that these numerous veins are less 
 persistent and carry ore-bodies which are more uncertain than 
 those, for example, of Battle Mt. and Raven Hill, where the 
 veins are obviously connected with dikes. It is possible to go 
 further and state that the explorations carried out in the ex- 
 treme eastern and western parts of the region, such as the 
 eastern part of Gold Hill and the corresponding slope of Big 
 Bull, both of which are still well within the volcanic area, have 
 tended to prove that the absence of dikes means the want of a 
 factor usually very favorable to the finding of ore. Nor is this 
 a matter of surprise. The veins are obviously the sequel to 
 the volcanic activity which occurred in this region, and it is a 
 reasonable deduction that the agency of ore-precipitation was 
 linked to that of the thermal waters which marked the last 
 stage of the dying volcano. 
 
 The principal veins, such as those which have made rich 
 mines out of the territory controlled by the Independence, 
 Portland, Strong, Gold Coin, Granite, Anaconda, Elkton, Gold 
 King and other companies, either follow dikes or have a course 
 lying closely parallel to them. It is noticeable that the later 
 fracture constituting the vein is apt to be straighter than the 
 older line of fracture occupied by the dike ; so that the vein 
 may be compared to a road, alongside a river, which avoids the 
 excessive bends of the latter and keeps a course as straight as 
 is consistent with a given general direction, namely, that of the 
 river. The Independence main lode illustrates this observa- 
 tion, as the accompanying plan will indicate. (See Fig. 22.) 
 
THE LODES OF CRIPPLE CREEK. 
 
 37 
 
 This exhibits a portion of the first level where the vein is 
 mostly in the granite. It will be seen that when the vein- 
 fracture encounters the phonolite dike it follows the latter ; or, 
 looking at the occurrence from the opposite standpoint, when 
 
 -H- -h -* 
 
 s+ 
 
 the phonolite makes a sharp turn to the west, the vein main- 
 tains its general strike. Near Ko. 1 shaft the vein crosses the 
 dike. This is shown in greater detail in Fig. 23, at E-D, where it 
 is evident that the vein-fracture persists in its course despite the 
 
38 THE LODES OF CRIPPLE CREEK. 
 
 fact that it has to cross the sharp bend made by the dike. At 
 the place of crossing, E D, there are one or two small stringers 
 of ore which serve to connect the lode on either side of the pho- 
 nolite. Between C and E the ore, here 4 ft. wide, narrows 
 down, by steplike succession, from one joint-plane in the gran- 
 ite to the next. Beyond the ~No. 1 shaft, as will be seen in 
 Fig. 22, the Ipde widens until, at the contact, it is 10 to 15 ft. 
 across. At this contact, where the overlying breccia rests on 
 the granite, the ore is in decomposed granite, having no marked 
 boundaries save where, on the east, it lies against the dike. 
 Immediately north of the contact the vein narrows and crosses 
 the phonolite only to disappear. At lower levels it has been 
 traced much farther northward. 
 
 i*" E f**M 6R.ANITE, /7c?l PHONOL.IT& 
 
 Lj!^ -J i_y-J 
 
 NOPE'NDE NCE. GROSSING- DIKE 
 
 The obvious connection between phonolite dikes and veins 
 has led to the idea that phonolite itself is notably an ore- 
 carrier. This is scarcely true. The details of lode-structure 
 described earlier in this account indicate that the gold-ore ob- 
 tained from the phonolite comes mainly from the places where 
 the ore-bodies in the granite or in the breccia are in immediate 
 contact with the dikes ; or, if ore is found within the phonolite 
 itself, it is at isolated spots, where the line of a lode crosses a 
 dike and makes a scattering along the fractures produced by 
 the crossing. Mistakes in this connection have been made by 
 confounding phonolite with certain finer-grained breccias and 
 tuffs which, by impregnation with quartz, have put on the ap- 
 pearance of a close-textured crystalline rock. This happens 
 
THE LODES OF CRIPPLE CREEK. 39 
 
 frequently in the mines on Gold Hill. Where valuable ore is 
 really taken from phonolite, it will be found that its true char- 
 acter is sufficiently indicated by the fact that it is secured in 
 the form of " screenings." The fine, powdery material ob- 
 tained by passing the ore over a wire-screen (which separates 
 all the larger fragments, and concentrates the small proportion 
 of rich ore), occurs as an encrustation, of fluorite and tel- 
 lurides, which lines the numerous cracks of a phonolite dike. 
 That shattering of the dense, fine-grained siliceous rock ap- 
 pears to be an essential factor in the deposition of the ore. 
 In this connection it is a notable fact that the phonolite 
 dikes are found occasionally to widen into tongues or cores of 
 large dimensions, which, if they lie on the strike of a series of 
 veins, are so much shattered as to permit of a generous dis- 
 semination of ore. Such an ore-body, of noteworthy size and 
 richness, occurs in the Independence mine at the second, third 
 and fourth levels, pitching northward more flatly than the con- 
 tact with which it was originally supposed to coincide, causing 
 a confusion of ideas very detrimental to the development of the 
 mine. 
 
 The chief characteristic of the ore-bodies of Cripple Creek 
 is that they are essentially impregnations spreading outward 
 from lines of fracture ; therefore, it is not surprising that the 
 distribution of ore is affected by the changes in country. Prof. 
 Penrose has pointed out that " the character of the fissures of 
 the district is much affected by the nature of the rocks they 
 intersect,"* and it is but a further step to connect this observa- 
 tion with the distribution of ore. In discussing this aspect of 
 the inquiry it is preferable to avoid the use of terms such as 
 " fissure," with its old associations of open crevasses and gaping 
 cavities, and to risk the weariness of iteration by employing 
 the word " fracture," which goes no further than to suggest 
 dislocation or breaking without necessarily bringing in the 
 idea of an open space, because the experience of mining in the 
 Cripple Creek district is all against the theory that open spaces 
 are the necessary adjuncts to ore-deposition ; and Mr. Becker's 
 well-known dictum, made in connection with the Comstock, 
 that " the first condition for the formation of a quartz body is 
 
 " Geology and Mining Industries of the Cripple Creek District," U. S. Geol. 
 Survey, p. 143. 
 
40 THE LODES OF CRIPPLE CREEK. 
 
 an opening to receive it,"* is daily contradicted by the under- 
 ground workings of this district, as it has been by many others 
 with which I am familiar. The open spaces which are fre- 
 quently encountered, especially in the mines situated on the 
 south slope of Bull Hill and on Ironclad Hill, are, as a rule,f 
 notably unfavorable to the finding of ore ; and while certain 
 veins, among which the Bobtail, in the Independence mine, 
 may be instanced, are indeed marked by frequent " vughs " or 
 cavities, these cavities do not contain ore, nor is their presence 
 a factor in connection with the distribution of good ore ; quite 
 otherwise, all such " pot-holes " are disliked by the mine- 
 foremen, because they coincide with lean places ; and by this 
 is understood not only poverty in respect of gold-bearing min- 
 erals, but also an absence of gangue, such as quartz, fluorite, 
 and the other constituents of the ores of the region. This all 
 goes to show that the term " fissure " and the associations 
 which go with it are to be avoided in an attempt to convey the 
 real nature of the lode-structure, because it cannot be empha- 
 sized too much that the ores of the district occur as a disper- 
 sion into the rock where it is traversed by lines of fracture, not 
 only in the fracture itself, which is often only a mere parting, 
 but also along the minor cracks and porosities of the enclosing 
 rock. * 
 
 The physical and chemical characters of the rock the first 
 more than the second are, consequently, a primary factor in 
 determining the shape and extent of the impregnation which 
 constitutes the lode. Close-grained rocks are apt to be more 
 fissile and less porous ; coarse-textured rocks are likely to break 
 in a larger, more irregular manner, but they are often more 
 penetrable by solutions. The phonolite and the breccia exhibit 
 extreme divergence in this respect. Granite resembles the 
 breccia because it is coarsely granular, but its jointings are 
 more regular; basalt resembles the phonolite in texture, but, 
 
 * Quoted from the Comstock monograph. 
 
 f An interesting exception was recently encountered on the seventh level of 
 the Elkton mine, where a cavity, having maximum dimensions of 20 x 20 x 35 
 ft. , was found to contain ore and water. The latter was struck in such quantities 
 as seriously to impede operations ; the ore occurred in a mass of brecciated rock, 
 lining the fractures and penetrating the shattered country, especially near the 
 periphery of the mass. It looked like a thermal spring which had become 
 choked before reaching the surface. 
 
THE LODES OF CRIPPLE 'CREEK. 41 
 
 on account of its basic composition, the weak places in it are 
 more readily searched out by corroding waters. 
 
 This " structural dependency " (as it may be termed) of the 
 lodes in relation to the rock is manifested not only by the char- 
 acter of the vein-fractures but also in the manner of their im- 
 pregnation by ore. Thus, while the bands of ore in granite 
 are often wanting in walls, yet on the whole they are less lack- 
 ing in definition than the breccia, because structural lines in 
 the granite, such as joint-planes, have served as barriers to in- 
 definite impregnation. On the other hand, the breccia, not 
 being composed of a crystalline granular material, but being 
 built up by fragments which are confusedly mingled together, 
 has no defined system of joints, and the width of the impreg- 
 nation which constitutes the ore will be determined by purely 
 local conditions of fracture ; the lodes may have no walls, and, 
 when they are limited by such boundaries, these are apt to be 
 cracks sympathetic with the main vein-fractures and parallel to 
 them. In the phonolite the limits are set up by the sheeting 
 of that rock ; the ore, which is infrequently found in phonolite, 
 occurs then as a lining or powdery encrustation upon the faces 
 of the laminae, and not, as a rule, within the matrix of the 
 rock itself. As the lamination is parallel to the walls of these 
 dikes, the width of ore also has a shape conforming to them. 
 
 Faulting on a large scale is conspicuously absent in the mine- 
 workings ; that is to say, there is no evidence of extensive 
 movement since the ore was deposited. Penrose has recorded 
 his opinion that " the fissures represent fault-planes of slight 
 displacement."* The amount of this displacement is not meas- 
 urable, because, as a matter of fact, the multiplicity of the 
 fracturing and the subsequent precipitation of ore has obscured 
 it most effectually, and it is this character of multiple fracture 
 which pervades the entire structure of the volcanic area. To 
 what extent these fractures are merely shrinkage-cracks and 
 to what extent they represent radical movements due to the 
 readjustment around a volcanic orifice, I cannot say. In so far 
 as the question concerns ore-deposition, one can emphasize the 
 fact that all breaks, from a crack to a crevasse, are the outward 
 and visible signs of displacement; for without displacement 
 
 * "Geology and Mining Industries of the Cripple Creek District," U. S. Geol. 
 Survey, p. 153. 
 
42 THE LODES OF CRIPPLE CREEK. 
 
 the fracture is only latent, and a latent fracture has no possi- 
 bilities for ore-deposition and does not concern the mining ge- 
 ologist. Since the ore was formed conditions of comparative 
 rest must have supervened, for this is a direct inference from 
 the comparative absence of faults. This fact, taken with the 
 known age of the volcano, which broke out so late in geologi- 
 cal time as the end of the Eocene or early in the Miocene 
 period, points to the recency of the agencies which made the 
 ore-deposits. 
 
 BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other 
 errors or communications for publication as u Discussions," or 
 independent papers on the same or a related subject, are earn- 
 estly invited. 
 
SUBJECT TO EEVISIOX. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 Vein- Walls. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 (Pittsburgh Meeting, February, 1896.) 
 
 FROM time immemorial the fissure-vein has been held the 
 simplest type of ore-deposit. The prominence given to it by 
 Cotta and his disciples, from their study of the mines of the 
 Erzgebirye, is impressed upon technical literature; and, in 
 in consequence, the ores which carry the valuable metals have 
 been supposed to occur mainly in fissures, cleaving the rocks 
 in diverse directions, and the noblest type of vein has been 
 deemed that which cut across the country independent of its 
 structure, whether evidenced as bedding, foliation or cleavage, 
 and which was identified with rents produced in the rocky crust 
 of the earth. 
 
 As so conceived, the vein was a fissure filled with ore, extend- 
 ing through the country for a varying distance, and continued 
 downward to a depth more or less proportionate to its longi- 
 tudinal extent. The vein-material was bounded by an encase- 
 ment of rock, and those immediate surfaces which limited it 
 on either side were called " walls." 
 
 These primary conceptions have become modified by the ex- 
 perience of modern mining in widely separated regions. The 
 study of lode-formations has led to the recognition of notable 
 departures from the supposed normal structure of the veins of 
 Saxony and Cornwall, the two classic homes of early economic 
 geology. 
 
 Typically the walls of a vein are conceived as parallel rock- 
 planes enclosing the ore ; the upper one being called the " hang- 
 ing," and the lower the " foot-wall."* 
 
 Walls are rarely alike. Even where a vein traverses a 
 homogeneous formation, such as a massive crystalline rock, it 
 is usually found that the surface which bounds it underneath 
 
 * The French equivalents are le toit, "the roof," and le mur, literally, "the 
 wall.'' In German, df(s Hangende and das Lieyende. 
 
 1 
 
2 VEIN-WALLS. 
 
 differs from that which limits it overhead. This is to be as- 
 cribed to the effect of the agencies which brought about the 
 deposition of the ore. The action of underground waters tends 
 at first to affect both equally ; but in many cases probably the 
 solutions, as they slowly ascend along the line of fissuring, are 
 prevented from penetrating into the encasing rock by the occur- 
 rence of an impermeable covering of clay, due to abrasion, 
 which may line either wall, but, because of gravity, generally 
 accompanies the under one. Similarly we are justified in sup- 
 posing that the deposition of a mineral deposit may form a 
 coating which would serve to protect the fooi^wall from the cor- 
 roding effects of chemical action. The activity of the mineral- 
 bearing current thus becomes diverted in its greatest intensity 
 toward the upper wall, where the decomposition of the rock- 
 surface may be followed by its disintegration so as to cause the 
 exposure of fresh faces for further dissolution. 
 
 Illustrations of these conditions may be seen in Figs. 1 and 
 2. The first is reproduced from a sketch made June 25, 1895, 
 in the lower level of the Union and Companion mine at Cornu- 
 copia, Union county, Oregon. It represents the breast of the 
 north drift on the west vein. The country, a fine-grained 
 granite, is not visibly altered under the foot-wall ; but along the 
 hanging it exhibits an alteration of its more soluble ingredients. 
 There is a slight selvage, D, separating the granite from the 
 pay-ore, C, which is about 10 inches thick, and consists of rib- 
 bons of quartz, impregnated with pyrite and alternating with 
 strips of altered country. A distinct parting, unaccompanied 
 by any apparent selvage, divides this streak of ore from one, B, 
 below it, which is twice as thick, but much less gold-bearing. 
 This part, B, of the vein consists of white quartz, carrying occa- 
 sional patches of pyrite, and marked by large inclusions of 
 slightly altered country, arranged along the foot-wall, where a 
 thin selvage separates them from the outer granite. The evi- 
 dence of vein-structure embodied in this figure permits diverse 
 interpretations. The upper pay-streak, C, appears to me to be 
 country-rock, in place, decomposed, fractured, and silicified, 
 with accompanying precipitation of gold. The central wall 
 may have been the original hanging-wall. The present foot- 
 wall is sufficiently distinct ; but the occurrence of the pieces of 
 enclosed country leads me to believe that at an earlier stage 
 
VEIN- WALLS. 
 
4 VEIN-WALLS. 
 
 the foot-wall was broken and irregular ; the shape and position 
 of the fragments of rock now lying upon it being such as to 
 render it doubtful that they could have been detached from the 
 hanging. 
 
 Fig. 2* was drawn May 10, 1893, in the ~No. 4 level, north, 
 of the Hillside mine, Yavapai county, Arizona. The lode oc- 
 cupies a strong fissure, cutting almost vertically through the 
 nearly horizontal layers of a quartzose talc schist, B B. The 
 original line of fracturing is probably now occupied by the 
 seam, C, 6 inches thick, of white talcose clay, covering the foot- 
 wall. The ore-bearing portion, D, of the lode is formed by an 
 irregular mineralization of the hanging-wall country, extending 
 to a distance of from 15 to 18 inches, and presents an intricate 
 medley of quartz, pyrite, zinc-blende and a little galena, carry- 
 ing about 1 ounce of gold and 25 ounces of silver per ton. 
 
 The most noteworthy feature of the section is the occurrence 
 in the hanging, on the outer confines of the main ore-streak, of 
 several irregular cavities, A A, whose inner surface is covered 
 by a series of siliceous coatings, evidently deposited by min- 
 eralizing waters that have circulated through them. Along 
 the outcrop of the lode, at Wikiup Point, there occur hollows 
 in the schists, of a character similar to those above described, 
 and of such a shape as to suggest that their origin was due to 
 the removal, by waters carrying carbonic acid, of certain por- 
 tions of the country, rendered soluble by the segregation of 
 lime. As the fourth level nearly follows the water-level of the 
 mine, and the siliceous encrustations were stained with iron 
 oxide, the formation appears to have been due to w T hat Posepny 
 called the Vadose circulation. On the other hand, the im- 
 pregnation of the hanging-wall country by sulphides cannot be 
 ascribed to oxidizing waters, and must have taken place at an 
 earlier period, when the surface was relatively more distant. 
 
 The lode follows a fissure formed along the axis of a syn- 
 clinal bend in the schists, and often very noticeably reproduces 
 the structure of the country which it has in part replaced ; the 
 ore breaking along lines corresponding to the almost horizon- 
 tal foliation of the schists. The width of the ore is very ir- 
 regular. That occasionally found under the clay seam is rarely 
 rich enough to mine ; the main pay-streak being that portion 
 
 * See also Tram., xxiv., 945. 
 
VEIN-WALLS. 
 
 of the vein bounded underneath by the clay and extending into 
 the hanging until the mineralization becomes so meager that 
 " ore " becomes " country-rock." 
 
 Fig. 3. 
 
 'LIMESTONE (J 
 CD QUARTZ 
 
 COARSE SANDSTONE 
 
 FINE GRAINED SANDSTONE 
 
 RHODOCHROS.TE SORE 
 ENTERPRISE MINE, COLORADO. 
 
 When a vein occurs in a formation composed of several kinds 
 of rock it may cut across the lines of parting and be labelled a 
 " true fissure ; " or it may conform to them, and become a 
 
6 VEIN-WALLS. 
 
 " bedded vein," if the two beds happen to be similar, or a 
 " contact-vein," if they are dissimilar. It is evident that, when 
 a vein crosses the bedding of a series of sedimentary rocks, the 
 differences between the enclosing walls at any given place will 
 depend upon the thickness of the beds traversed, and the ex- 
 tent of the faulting of the country along the line of the fissure. 
 When the faulting is slight, the change in the wall-rock will be 
 practically simultaneous for both sides of the vein ; while, when 
 the dislocation is equal to, or exceeds, the thickness of the 
 members of a series of dissimilar beds so intersected, the oppos- 
 ing walls may be entirely dissimilar. This is illustrated in Figs. 
 3 and 4. 
 
 Fig. 3 represents the breast on August 14, 1894, of the north 
 drift of the Jumbo ~No. 2 vein, on the Group tunnel level, in 
 the Enterprise mine, at Rico, Dolores county, Colorado. The 
 vein follows a fault-fissure through a series of lower carbonifer- 
 ous shales, limestones and sandstones. The throw of the fault, 
 along which the ore has been deposited, is about 2 feet ; the 
 thickness of the prominent bed of limestone is 3 feet ; and the 
 section shown in the figure covers 7 feet by 6. It is charac- 
 teristic of the veins in this mine that they 'split up and be- 
 come impoverished in lime, while in the sandstone, on the 
 contrary, they usually become clean-cut, compact and richly 
 ore-bearing, as is the case at the top of the drift represented 
 in the figure. In traversing the lime, the selvage following 
 the line of fissuring is very noticeable; but in the sand- 
 stone, particularly where the vein splits, the ore is " frozen," 
 that is, has no evident parting separating it from the encasing 
 rock. 
 
 Fig. 4 is taken from a drawing accompanying a note by Mr. 
 E. J. Dunn, of the Victorian mining department, contributed 
 by him to the Quarterly Report of December 31, 1888. It rep- 
 resents certain features of the Sunday reef, near Beechworth in 
 Victoria (Australia). The country consists of Silurian slates 
 and sandstones, which have been faulted about 2 feet. Along 
 this line of faulting gold-bearing quartz has been deposited ; 
 and it is noticeable that its occurrence is mainly confined to the 
 under side of the sandstone, while under the slate it disappears 
 and gives place to fluccan or clay. I would suggest that the 
 lenticular shape of the quartz-bodies indicates that the spaces 
 
VEIN-WALLS. 
 
 i? 
 
8 VEIN-WALLS. 
 
 occupied by them were produced by the movement of one of 
 the walls of a fissure, following a line whose undulatory form 
 was caused by the unequal texture and hardness of the beds 
 traversed by it. 
 
 Of the change observable in the character and value of the 
 mineral ingredients of a vein in its passage from one kind of 
 rock into another it is hardly possible to speak in parenthesis. 
 One of the best known examples is that of the old Dolcoath 
 mine in Cornwall, where the vein, in leaving the clay-slate 
 (killas) and penetrating the granite, changed from a copper- 
 bearing into a tin-bearing lode. I might also mention the sil- 
 ver-lead veins of Pontgibaud,* in France, which are in a gneiss 
 country, diversified by dikes of granulite. The ore-veins have 
 been formed along fractures within the dikes, and on their line 
 of contact with the gneiss. When the dike diminishes in size, 
 the ore decreases in width ; when the vein penetrates into the 
 gneiss, the ore disappears. The best ore is associated with the 
 kaolinization of the feldspar of the granulite ; and when the 
 latter becomes hard and unaltered in depth, the ore pinches 
 out. 
 
 On Newman Hill, Rico, Colorado, the veins of rich gold- and 
 silver-bearing ores are noticeably affected by the character of 
 their rock-walls. The particular changes due to penetrating 
 from lime into sandstone have already been mentioned in con- 
 nection with the veins of the Enterprise mine, but there is also 
 the more general observation, that when the sedimentary beds 
 are black, the veins in them are rich ; when they lose that 
 black color, the ore diminishes. 
 
 Other instances occur to me, but the above are typical. This 
 inter-dependence between country and ore has been used as an 
 argument in support of the now crippled lateral-secretion 
 theory. It has been suggestedf that this relation, often no- 
 ticed in vein-mining, points to the derivation of the ore from 
 the enclosing rock, and that some formations have an enriching 
 effect, because they have been the source of the valuable metals 
 
 * See " The Lodes of Pontgibaud," by the writer, in the Eng. and Mm. Jour. 
 of August 11 and 18, 1894. 
 
 f As, for instance in the paper ' ' On Some Evidences of the Formation of Ore- 
 Deposits by Lateral Secretion in the John Jay mine, at Providence, Boulder 
 county, Colo.," by P. H. Van Diest, in the Proceedings of the Colorado /Scientific 
 Society, vol. iv., p. 340, and in the discussion of the said paper, Id., p. 340. 
 
VEIN-WALLS. 
 
 o 
 
10 VEIN-WALLS. 
 
 now found in the veins penetrating them. But as Cotta long 
 ago suggested, the influence of the physical texture and chemi- 
 cal composition of the country, as facilitating the deposition of 
 the ore, may explain this phenomenon. The former would affect 
 the rate of cooling and the formation of adhesive crusts. The 
 latter would act by direct chemical precipitation. 
 
 As I suggested in the discussion of the paper just referred to, 
 the local enrichment or impoverishment of veins may be ex- 
 plained by the presence or absence in the enclosing formation 
 of precipitating agents. What the agent has been we can only 
 in rare instances guess. At Rico it was undoubtedly the car- 
 bonaceous matter enclosed in the Lower Carboniferous shales, 
 limestones and sandstones. At Pontgibaud it was probably the 
 feldspar which made room for the silver-bearing galena, and in 
 Cornwall also the beautiful pseudomorphs of tinstone after 
 feldspar suggest similar chemical interchanges. 
 
 In the case of veins which lie along the bedding-planes of 
 sedimentary rocks, the dissimilarity between the enclosing 
 walls may not go further than a slight difference in the grain 
 of two beds of sandstone, the color of two beds of slate, etc., or 
 it may reach the more marked diversity presented by rocks as 
 entirely unlike as a quartzitic sandstone and a soft slate. 
 
 Fig. 5 represents a gold-vein, following the bedding of, and 
 encased by, a band of black slate, which is in turn flanked on 
 either side by light gray slates. The ore consists of ribbons of 
 quartz, mingled with strips of included country, and separated 
 from the outer slates by a selvage, faint on the hanging- but 
 strong on the foot-wall. The drawing was made July 3, 1895, 
 in the upper level of the Bonanza mine, Baker county, Oregon. 
 
 The comparatively straight walls of ordinary vein-mining 
 occasionally give place in veins of the bedded class to surfaces 
 having a marked curvature. Such walls characterize the sad- 
 dle-reef, a type of lode-structure common in only two known 
 mining districts, namely, Bendigo in Australia and Waverly in 
 Nova Scotia unless it be true, as is now stated on good au- 
 thority, that the Broken Hill lode in New South Wales is also 
 a saddle-reef. 
 
 In these regions, gold-bearing quartz is found along the bed- 
 ding-planes of folded sedimentary rocks. While anticlinal 
 folds (or saddles) alternate with synclines (inverted saddles or 
 
VEIN-WALLS. 
 
 11 
 
 + L +J-,*"!. V ** * 4- f. , -r 4- , * ^ -C v 
 
 -^>j^i^S^<^;^ 
 
 v v ^ 
 
12 VEIN-WALLS. 
 
 troughs), experience has shown that the ore-deposition is mainly 
 confined to the former. Such a formation will offer many 
 striking features, because of the occasionally very regular cur- 
 vature of the walls. I remember, for instance, standing in the 
 stopes just above the 980-foot level in the Johnson's mine at 
 Bendigo, and seeing the foot-wall curve underneath like the top 
 of a boiler, while the hanging arched overhead like a Roman 
 bridge. This was the apex of a saddle, as illustrated in Fig. 7, 
 reproduced from a sketch made at the time.* The lode is seen 
 to consist of white quartz about 2J feet thick, separated from 
 the overlying sandstone by a very regular parting of black clay. 
 Underneath is about a foot of sandstone, then a dark seam of 
 slate, from 5 to 6 inches thick, whose parting from the next bed 
 of sandstone is marked by streaks of quartz, thinning out both 
 east and west. 
 
 The downward continuation of such a formation (the " legs 
 of the saddle ") presents the appearance of an ordinary bedded 
 vein, usually marked, however, by a noteworthy want of per- 
 sistence of ore in depth. Of the many drawings illustrating 
 such veins already contributed to the Transactions^ I have re- 
 produced, in Fig. 6, the breast of the north end of the 1990-foot 
 level in the Shenandoah mine at Bendigo. The lode carries 2 
 feet of closely-laminated quartz, from which spurs or stringers 
 go off into the underlying sandstone. The hanging shows a 
 gouge or selvage, J separating the quartz from the overlying 
 slate. 
 
 Many veins follow the contact between eruptive dikes and 
 the metamorphic or sedimentary formations which they have 
 penetrated. The dikes of quartz-andesite porphyry traversing 
 the granitoid gneiss of the earliest mining districts of Colorado 
 (in Boulder, Gilpiri and Clear Creek counties) offer many ex- 
 amples of this type of vein-structure. In such cases the miner- 
 alization may often be found to have spent itself on the more 
 
 * Octobers, 1890. See also Trans., xx., 506. 
 
 f By the writer in vols. xx. and xxi. 
 
 J "Selvage," "gouge," "dig," "pug," "fluccan" are all more or less syn- 
 onymous. "A layer of soft stuff" would cover them all. It is perhaps worthy 
 of notice, however, that our " selvage," used in this sense, is not the exact syno- 
 nym, as it has often been supposed to be, of the German Saalband. A Saalband is a 
 definite wall, as distinguished from a gradual transition from vein-matter into 
 country-rock. A layer of soft material on the wall is a Besteg. 
 
VEIN-WALLS. 
 
 13 
 
 ^vV, 
 
 i 
 
 ' v \-r X I 
 
14 VEIfr-WALLS. 
 
 soluble porphyritic igneous rock, rather than upon the less 
 soluble metamorphic. The walls of such veins will vary, as 
 the ore deposition has followed either fractures along the im- 
 mediate contact, or those which ramify into the body of the 
 dike, or those again which cut across the latter, where its irregu- 
 lar outline has been an obstacle to the main line of fissuring. 
 These ideas are illustrated in the diagrams A, B and C, Fig. 8. 
 
 The California mine, in Gilpin county, offers many examples 
 of such vein-phenomena. Figs. 9 and 10 represent the western 
 ends of the 2000-foot and the 2100-foot levels, as seen on July 
 13, 1892. In the first the vein is seen to lie between mica- 
 schist, on the foot, and " porphyry," on the hanging. The 
 " porphyry" forms part of a dike, 17 feet thick, of dacite or 
 quartz-andesite, and is both brecciated and much decomposed 
 near the lode, from which it is separated by a dark band of 
 " flint," which consists of small fragments of porphyry ce- 
 mented together by a very dark chalcedonic quartz. Under- 
 neath this there are 5 inches of white kaolinized porphyry, 
 containing threads of iron and copper pyrites. Next comes an 
 inch and a-half of quartz and feldspar intermingled ; then a band 
 of included country, part gneiss and part mica-schist, which is 
 subdivided by a streak of pyrite. Finally there is an irregular 
 foot-wall ; the load-filling shading off into the soft mica- 
 schist which underlies the vein. 
 
 The lower level, shown in Fig. 10, exhibits a marked differ- 
 ence. The lode has crossed the dike, and the porphyry forms 
 the foot-wall. Next comes a thickness of 6 to 8 inches of white, 
 soft, decomposed porphyry, then a black selvage, with slicken- 
 sides on the lower side. Then come two bands of mineralized 
 porphyry, separated by thin partings. The main width of ore 
 consists of about 2 feet of lode-filling traversed by patches and 
 streaks of pyrite. Fragments of porphyry can also be recog- 
 nized in it. This is separated from the overhanging gneiss 
 and mica-schist by a selvage of varying thickness. 
 
 In the neighboring Indiana claim, the California vein exhib- 
 its certain changes, the most evident of which are the absence 
 of selvages, the indistinctness of its limits and the brecciation 
 of the vein-filling. This is suggested in Fig. 11, which repre- 
 sents the breast of a stope above the 800-foot level west, as ob- 
 served November 13, 1895. The enclosing country, A A, is a 
 
VEIN-WALLS. 
 
 15 
 
 granite almost destitute of mica. The part B is bespattered 
 with pyrite. The best ore is a seam, C C, of black zinc-blende 
 lining the hanging-wall. D is evidently brecciated. The 
 larger part of the section consists of slightly altered country (E 
 E) reticulated with seams of blende, following joint-fractures. 
 The foot-wall of the vein is considered to be under the bands of 
 zinc-blende and copper pyrites occurring along F F. The en- 
 
 Rg. 
 
 tire width is about 4 feet. The lode has departed from the 
 dike, with which it is so closely associated in the neighboring 
 mine ; but the workings show that it meets this dike at inter- 
 vals, and is benefited by the intersection. 
 
 That the vein follows the line of a fault can be seen by ex- 
 amining the walls of the 2000-foot level in the California mine, 
 more particularly at points between 350 and 450 feet west of 
 the shaft, where the lode has left the dike entirely, and is en- 
 cased in the gneiss and mica-schist. The country-rock on the 
 two sides of the drift is not the same. The extent of the throw 
 of the fault, however, could not be measured. 
 
16 VEIN-WALLS. 
 
 In the course of the foregoing descriptions of lode-structures, 
 mention has been repeatedly made of the occurrence of clay 
 selvage, following sometimes one, sometimes both, of the walls 
 of a vein. This " clay " may occasionally be material precipi- 
 tated from solution ; ordinarily it is only crushed rock. It fre- 
 quently encloses exquisite mineral specimens, because its soft 
 consistency has permitted untrammeled crystalline growth. 
 Most examples of well-developed crystals of native gold have 
 been discovered under such conditions. This is the case at 
 Cripple Creek, Colo., where the gouge or clay has been dried 
 and hardened near the surface, and as a crumbly earth, made 
 purple by the presence of fluorite, carries beautiful crystals of 
 gold pseudomorphic after sylvanite and calaverite. The exquisite 
 leaf-gold specimens, for which Farncomb hill (Breckenridge, 
 Summit county, Colo.) is so famous, are found imbedded in 
 talcose clay. Large pieces of pure argentite are often found in 
 such an environment, as at the De Lamar mine, in Owyhee 
 county, Idaho. Wire-silver also has been found in compara- 
 tively large amount encased in such a " mud " in many Lead- 
 ville mines; notably at the Crown Point, in 1886. 
 
 By reason of their opposition to the passage of water such 
 seams of clay protect the rock-surface of vein-walls, and under- 
 neath them there will occasionally be found comparatively fresh 
 and unaltered rock having beautifully polished faces or slicken- 
 sides. At Ballarat, in Australia, I have seen many such rock- 
 faces like finished ivory in their smoothness, and streaked with 
 black lines, due to the grinding of specks of pyrite. In the 
 Bonanza mine, Baker county, Ore., there could be seen quite 
 recently an exquisite example of such an occurrence. In an 
 upper drift there was at one place a surface of a few feet square 
 (on one of the Avails of a gold-bearing quartz-vein) covered by 
 a thin layer of black clay, under which lay what seemed a white 
 enamel of very remarkable delicacy. It could not be removed 
 without breaking, because it was very friable, consisting essen- 
 tially of crushed quartz partially recemented, probably by 
 pressure. 
 
 " The handwriting on the wall " is not always easy to deci- 
 pher. The lines or striae occasionally to be seen upon its sur- 
 face have been held to indicate the direction of that movement 
 (or succession of movements) of the opposing rock-planes to 
 
VEIN-WALLS. 
 
 17 
 
 which the deposit of ore primarily owed the opportunity for its 
 existence. These lines, however, sometimes have opposite di- 
 
 \--\- 
 
 rections within a short distance and otter conflicting evidence 
 hard to explain. 
 
 2 
 
18 VEIN-WALLS. 
 
 Rarely is a story told more clearly than in the ripple-marked 
 foot-wall which was to be seen in October, 1891, in the John- 
 son's mine at Bendigo. It had been very difficult to distinguish 
 the bedding of the country because the development of a 
 strongly-marked cleavage had obliterated the lines of original 
 sedimentation. At the 106 5-foot level, however, the matter was 
 made plain. For more than 100 feet square the surface of the 
 foot-wall was covered with ripple-markings. The crests of the 
 waves were about 3 inches apart and presented all the little ir- 
 regularities to be seen to-day when the wind blows over the shal- 
 low waters of an estuary and imprints the evidence of its action 
 upon the yielding sand. The markings had been protected 
 by layers of Silurian sediment, and the whole series had been 
 indurated into rock, the sand which bore the markings becom- 
 ing quartzitic sandstone, and the overlying mud slate. Between 
 them, as within the pages of a book, was preserved the conclu- 
 sive evidence of the original position of the beds of rock enclos- 
 ing the reef, which had been formed in later times, when fissur- 
 ing had made room for the circulation of underground waters 
 and the deposition of the gold-bearing quartz. 
 
 In the above interesting case the corrugation of the foot-wall, 
 due to the ripple-markings, rendered difficult the detachment 
 of the ore. Distinct walls, especially when accompanied by 
 selvage, are very useful in actual mining ; but they are not by 
 any means necessarily indicative of a productive vein, or par- 
 ticularly favorable to the continuity of the ore. A " clean " 
 wall and a good " gouge " are welcomed by the miner because 
 they ease his toil ; but the idea that their presence alongside a 
 lode gives it a character better than another unprovided with 
 such adjuncts is a dangerous delusion. In many mines, more 
 ore has been lost through the persistent following of a " wall," 
 without exploring beyond it, than was ever compensated for by 
 the' greater facility given by such a parting-plane for the break- 
 ing of the ore found. 
 
 Many veins have no defined walls, but gradate imperceptibly 
 into the enclosing country, and are bounded only by the com- 
 mercial value of the material mined. Such veins are to be 
 seen, for instance, in the mountains that overlook Silver Plume, 
 Clear Creek county, Colo. Fig. 12 represents a sketch made 
 May 27, 1892, from the 300-foot level of the Seven-Thirty mine. 
 
VEIN-WALLS. 
 
 19 
 
 A fracture penetrating the metamorphic granite carries ore on 
 both sides, which diminishes in richness as it spreads into the 
 encasing country. The joints in the granite are evident. 
 
 In this mine the so-called " walls " are often simply two 
 parallel veins (rich, but very small), separated by clean, hard 
 country. This is illustrated in Fig. 13, which was obtained 
 
 Fig. 14. 
 
 CANTON MINE 
 
 from the same level about 1000 feet further east, The grani- 
 toid gneiss is traversed by two streaks of ore, of which the one 
 to the right is much the richer. Between them there are at 
 least two well-marked parallel fractures devoid of ore. The 
 vein to the left has a thin selvage, under which there is a streak 
 of quartz carrying a little silver-ore; but the companion-vein to 
 the right follows a fracture, unaccompanied by any selvage, 
 whose upper side is impregnated with about 3 inches of tetra- 
 hedrite, galena, and polybasite. 
 
20 VEIN-WALLS. 
 
 Where ore is absent in the Seventy-Thirty mine, the walls 
 are apt to be particularly well-defined ; and when there is any 
 thickness of rich silver-bearing mineral present, the walls are 
 scarcely to be distinguished, and the rock is hard to break, be- 
 cause it is destitute of convenient partings. The large veins 
 carrying gouge are found to be uniformly poor, except where 
 they meet the very narrow rich streaks which constitute the 
 resource of the property. The Seven-Thirty vein proper is 
 only 2 J inches thick, but it is very persistent through the midst 
 of hard crystalline rocks, and it has, for twenty years, proved 
 very productive. 
 
 In many mines one vein only is exploited, and cross-cutting 
 the country in search for parallel lodes is entirely neglected. 
 In others, a cross-cut is stopped as soon as it reaches the further 
 wall of the particular vein it was started to reach. Both these 
 unwise practices are founded upon a misconception of lode-struct- 
 ure, due to a narrow interpretation of the early teachings of 
 economic geology, which lays a misleading emphasis upon the 
 definition and clean-cut boundaries of so-called " true fissure- 
 veins." The fact is, as daily observation proves, that there* are 
 walls within walls, and walls beyond walls ; and that to follow 
 closely any particular hard, smooth rock-surface, with the idea 
 that it is the utmost limit of ore-occurrence in any particular 
 mine, is to be blind to the realities of geological structure. 
 
 Fig. 14 represents the face of a drift* in the Canton mine, 
 near Waipori, Otago, New Zealand. A A is the reef, a vein 
 of quartz which is supposed to lie immediately upon the foot- 
 wall. Along B B the quartzose schist is soft, and the included 
 quartz-folia are much twisted. C C is one of .the so-called 
 " false hanging-walls." Along A A and C C faulting is evi- 
 dent, along B B distortion only. It was not possible to say 
 where the lode ended, or where it began. The whole width 
 from A to C was known to be gold-bearing, although A A 
 served as a guide in following the gold-bearing channel. 
 Nevertheless those who were working the mine had little com- 
 prehension of the formation, particularly of its essential lack 
 of definition, and, while admitting that there were several 
 " false hanging- walls," insisted that there was only one foot- 
 wall (underneath A A) which was stated to be of a different 
 
 * On November 15, 1890. See also Trans., xxi. , 415. 
 
VEIN-WALLS. 
 
 21 
 
 kind of rock, and exceptionally hard. On examination I found 
 that the rock of the supposed foot-wall was similar to that of 
 of the rest of the gold-bearing country forming the lode, and 
 on a sample of it being crushed and tested in a prospector's 
 
 Fig. 15. 
 
 + t- 
 
 GRANITE /// PYRITES 
 
 ^ SELVAGE AND CRUSHED ROCK 
 
 RIBBON QUARTZ 
 \Z?\ QUARTZ 
 
 UNION AND COMPANION MINE, OREGON. 
 
 pan, it was discovered to be richer than that which was being 
 actually mined. It was scarcely necessary after that to insist 
 that a cross-cut should be made into the foot-wall. 
 
 Fig. 15 represents the north breast* of the lower level on 
 the main lode in the Union and Companion mine, Union 
 
 * On June 26, 1895. 
 
22 VEIN-WALLS. 
 
 county, Oregon. It illustrates the occurrence of " walls within 
 walls," for while the lode may be limited by the main boundaries 
 along E and D, there are at least two partings (G and H) equally 
 well-defined, subdividing the enclosed width of ore. The coun- 
 try is a fine-grained granite, which, near the hanging, is de- 
 composed and ore-bearing. D is a streak of granular crushed 
 country, mixed with lenticles of white quartz whose longer 
 axes are parallel to the lode-walls. D is from 3 to 7 inches 
 wide, and carries only traces of gold. A consists of white 
 hackly quartz spotted with iron pyrites. It is from 14 inches 
 to 2 feet wide, and contains about J an ounce of gold per ton 
 of ore. Then comes a hard regular "wall," separating A from 
 B, which is the main pay-streak, ribboned with veins of iron 
 and copper pyrites. The width is from 2J to 3 feet, and the 
 ore averages about 2 ounces in gold and 8 ounces in silver. 
 Then follows a parting marked by a slight selvage, underneath 
 which comes a 10- to 15-inch band (C) of ribboned white quartz, 
 stained by the oxidation of copper pyrites and carrying about 5 
 pennyweights of gold per ton. Then comes the main foot-wall 
 with its streak, 1 to 3 inches thick, of granular crushed country, 
 mixed with clay. The underlying rock is but little altered. 
 
 Fig. 16 affords an example of " walls beyond walls." It rep- 
 resents a section obtained at the station on the 500-foot level in 
 the Mammoth mine, Final county, Ariz. The Mammoth lode 
 traverses hornblende-granitite, porphyrite and a porphyry 
 agglomerate. The lode-filling consists of altered country, and 
 therefore changes as the lode in its strike penetrates first one 
 kind of rock and then another. When standing in the stopes 
 it is not difficult to recognize in the ore the reproduction of the 
 habit of either the granite or the porphyrite by whose altera- 
 tion the lode was produced. The country near the lode is 
 much altered and often visibly gradates into the ore, while, as 
 the lode is receded from, these effects diminish until they be- 
 come confined to the faces of the rock lining the fractures. The 
 granitite carries two feldspars, of which the pink orthoclase is 
 evidently more stable and succumbs to decomposition less 
 quickly than the green plagioclase. The ore is both gold- and 
 silver-bearing, but chiefly valuable for gold. The great variety 
 of associated minerals includes some uncommon species, such 
 as wulfenite (usually colored by vanadic acid), vanadinite, des- 
 
VEIN-WALLS. 
 
 23 
 
 cloizite, ecdemite, dechenite, linarite, besides the commoner 
 anglesite, pyromorphite, cerussite, malachite, dioptase, azurite, 
 and a little galena and pyrite. Referring- to the drawing (made 
 March 17, 1893), the edge of the ore is shown at A; it becomes 
 
 Fig, 16. 
 
 GRANITITE 
 
 VEIN QUARTZ 
 
 SELVAGE 
 
 (/?/&j GRANULAR FILLING , 
 
 MAMMOTH MINE, ARIZONA. 
 
 mixed with altered granular country (along B) in approaching 
 the "main footwall." This is followed by the granitite itself, 
 in which there are well-defined walls (or fractures parallel to 
 the lode-channel) and cross-joints, often lined with exquisite 
 crystals of vanadinite and wulti'iiite. 
 
 Going to the Pacific coast, Fig. 17 represents a part of the 
 west side of the so-called " mother lode " of California. The 
 
24 VEIN-WALLS. 
 
 drawing, made May 21, 1891, is a portion of the face of a large 
 open cut at the Gold Cliff mine, Angel's Camp, Calaveras 
 county, Cal., near the now well-known Utica mine. The ore- 
 channel consists of a country-rock traversed by cross-veins of 
 white gold-bearing quartz. The country-rock is a greenish 
 gray augite schist (probably at one time a diabase), carrying 
 coarse pyrite near the gold-quartz. 
 
 There are " walls " ad infinitum. Each cuts off the quartz- 
 seams, which occur again on the further side and extend to the 
 next " wall," where they are terminated as before, and so on. 
 A certain portion, 20 to 30 feet in width, of this channel of 
 country is rich enough to work, and is sent to the mill, but the 
 poorer material which lies beyond it has an identical geological 
 structure. Of course, in such a case the " main walls " will 
 depend for their determination upon commercial rather than 
 geological conditions. 
 
 Another case in point is presented at the Cashier mine in 
 Summit county, Colo., as illustrated in Fig. 18, which shows a 
 part of an open cut on the lode, as seen August 22, 1895. The 
 latter consists of altered quartz-felsite, rendered porphyritic by 
 large crystals of feldspar. It is spoken of as a vein 45 feet wide, 
 having a hanging-wall of porphyry and a foot-wall of lime. The 
 ore is said to be penetrated by dikes of porphyry. The facts 
 are really these : A certain width of quartz felsite within the 
 neighborhood of its contact with the limestone has been acted 
 upon by mineral solutions which probably came up along that 
 contact. There are no walls, the porphyry of the hanging be- 
 ing simply the rock of the ore-channel in a less altered condi- 
 tion. The feldspar of the lode-rock has been leached out. In 
 the cavities, now partially filled with crystalline quartz, iron 
 oxide and gold, there can be distinguished the outlines of the 
 large (J to 1J inches) crystals of orthoclase whose removal 
 made the rock porous to circulating waters. The mineraliza- 
 tion is indicated by the softening and reddening of the por- 
 phyry and is most marked along the joints, especially where 
 they intersect. There are occasional portions of the rock com- 
 paratively unaffected by the leaching agencies, and therefore 
 appearing as hard, unstained nuclei amid a mass of softer red- 
 dish ore. It is these that are locally termed " horses " and 
 " dikes " of porphyry. 
 
VEIN-WALLS. 
 
 25 
 
26 VEIN-WALLS. 
 
 Lodes subdivided by partings parallel to their outer walls (as 
 in numbers 1, 9, 10 and 12) often resemble twin veins such as 
 are actually formed by the temporary parallelism of two dis- 
 tinct fissures travelling together after they have united. Such 
 a case is shown in Fig. 19, which illustrates the union of the 
 Old and New Castletown veins as seen in the north face of the 
 500-foot level of the Drumlummon mine, Marysville, Mont. The 
 country is clay slate. A B is the Old Castletown vein, 2J feet 
 wide. B C is the New Castletown, 2 feet wide. There is no 
 selvage on any one of the three walls, but each is marked by 
 soft, crushed and foliated slate. 
 
 The generous lodes of silver-bearing copper-ore which at 
 Butte, Mont., penetrate the granite are frequently marked by a 
 brecciation of the encasing country and are accompanied by a 
 mineralization of the granite far beyond the walls or limits 
 of workable ore. In the 300-foot level of the Gagnon mine, 
 374 feet west of the main shaft, a cross-cut shows that the 
 lode-channel extends 30 feet north of the supposed foot-wall, the 
 enclosed granite being broken and mineralized. Beyond this 
 line the country ceases to be shattered and is no longer impreg- 
 nated with ore, but is comparatively fresh, hard, normal granite, 
 with a blocky fracture. This outer foot-wall of the lode-chan- 
 nel is marked by the occurrence of some ore-streaks and an ac- 
 companiment of seams of clay, as is shown in Fig. 20 (drawn 
 September 15, 1895). The foot-wall country has a noticeable 
 number of slips or joint-planes. It is separated from the lode- 
 channel by a thick layer of tough black clay. Then comes a 
 zone of kaolinized granitic filling traversed by irregular veins 
 of zinc-blende and pyrite. Another clay-seam divides this part 
 of the section from a band of mixed white quartz and granitic 
 filling, followed by altered mineralized granite, ribboned with 
 veins of gray quartz, whose southern limit is a third seam of 
 black clay. Then comes crushed, brecciated granite, diversi- 
 fied by quartz and occasional evidences of ore, which extends 
 to the main pay-vein (on the hanging) which has been the 
 workable part of the deposit. The section in the figure repre- 
 sents a width of 6 feet. 
 
 Fig. 21 came from the east breast of the 1300-foot level, in 
 the same mine. It is a representative section of the main ore- 
 bearing vein. Granite, visibly altered, marks the northern 
 
VEIN-WALLS. 
 
 27 
 
 11 
 
28 VEIN-WALLS. 
 
 edge of the section, which is the foot-wall. Upon it lie a few 
 inches of breccia, succeeded by 8 inches of blende, pyrite, and 
 enargite, well intermingled. Then come 3 feet of friable, 
 mineralized, light gray shattered quartz, giving place to 6 to 8 
 inches of harder quartz streaked with veinlets of chalcopyrite 
 and bornite. Upon this lies a foot of altered granite traversed 
 by streaks of quartz. Then 18 inches of low-grade ore, con- 
 sisting of quartz, pyrite, blende and a little bornite, separated 
 from the main pay-streak by 6 inches of granitic filling. The 
 main pay-streak is from 5J to 6 feet wide, and consists of a 
 massive mixture of pyrite, blende, enargite and bornite, carry- 
 ing about 60 per cent, of silica. Between this and the hang- 
 ing-wall there is 2 or 3 feet of decomposed broken granite, 
 showing small veins of ore which drop into the main pay-streak. 
 Beyond is granite. 
 
 In mines of this character, the geologist may determine the 
 existence of the lode far beyond the limits of workable ore ; but 
 the miner will rightly distinguish between what is mineralized* 
 country too poor to exploit and the concentrated mineral which 
 will yield a profit. 
 
 That straight walls are not the necessary adjuncts of a vein 
 of ore is suggested in Fig. 22, which represents the breast (on 
 September 26, 1895) of the hanging- wall drift on the upper 
 level of the Double Extension mine, in Summit county, Colo. 
 The lode-formation consists of gently sloping quartzite, cut 
 across and broken into by porphyry, which, as a dike, forms 
 " the main vein," and in the shape of sheets, intercalated 
 among the beds of quartzite, makes a succession of " floors " of 
 gold-bearing ore of widely varying hardness. In the particular 
 section illustrated, the intrusive porphyry forms the hanging- 
 wall, A B C, of a zone of ore which is limited on its lower side 
 by the ragged edges of the quartzite, M M. In this instance 
 the conventional straight walls give place to one of extreme and 
 irregular curvature and another of a markedly broken and 
 
 * The term "mineralized," like the word "mineral," is employed by miners 
 in a sense not sanctioned by the ordinary dictionary, though fully entitled by its 
 general usage to such recognition. Dr. Raymond's Glossary of Mining and Metal- 
 lurgical Terms gives this sense as follows : "Mineral. In miners' parlance, ore. . . . 
 Mineralized. Charged or impregnated with metalliferous mineral." The French 
 use mineral and mineraliser in this sense ; and I have adopted it because no English 
 equivalent occurs to me. 
 
VEIN-WALLS. 
 
 29 
 
 jagged outline ; but they are nevertheless walls, as truly as 
 would be the most perfectly straight, smooth rock faces. 
 
 1 
 
 mm 
 
 The porphyry, A C, a quartz-felsite, is bleached to a yellow 
 white and softened to a granular clay, as it approaches its con- 
 
30 VEIN-WALLS. 
 
 tact with the broken quartzite, D D. The latter is dark bluish- 
 gray, and carries, along its joints and other fractures, minute 
 seams of iron-stained ocherous clay, which is gold-bearing. E 
 E and G G are veins of such gold-bearing ocher. F F is crushed 
 quartzite, very similar to D D. The band of quartzite breccia, 
 H H, is separated from an equally wide band of porphyry- 
 quartzite breccia, L L, by a succession of thin parallel quartz- 
 seams, K K. Then comes the foot-wall itself. At N", under 
 the projecting curve of the porphyry of the hanging, there 
 is a mass of much-shattered quartzite mixed with iron-stained 
 quartz. This is all gold-bearing. 
 
 Fig. 23, representing the western edge of a " cutting-out 
 stope," near the supposed foot- wall of the lode (as seen Septem- 
 ber 23, 1895) exhibits a somewhat similar complication and 
 another curved " wall." To the extreme left is fractured quartz- 
 ite, carrying iron-stained clay along the faces of fractures, and 
 divided into two parts, H H and B B, by a narrow zone, A A, 
 of soft yellow porphyry, whose curved lines of alteration are 
 marked by streaks of gold-bearing ocher. The remainder of 
 the section is all porphyritic material, of which C C is similar 
 to A A; D D is a wedge of comparatively fresh rock, but 
 slightly kaolinized and full of pyrite, and E E and F F are lay- 
 ers of brown and reddish soft talcose porphyry and clay, sepa- 
 rated by numerous slips or smooth partings forming " false 
 walls." The " main foot-wall " was supposed for some time to 
 be the line of contact of the band of quartzite, B B, with the 
 underlying porphyry; but assays have shown that the soft de- 
 composed rock lying beyond it is fully as gold-bearing as the 
 quartzite, and can be mined with as much profit for several 
 feet beyond that line. 
 
 Not infrequently veins have irregular indistinct walls when 
 ore-bearing, and smooth, clearly defined ones when barren. 
 Fig. 24 illustrates the face (as seen September 15, 1895) of the 
 west drift of the 430-foot level on the middle vein in the Nettie 
 mine, near Butte City, Mont. The south country is a fairly 
 hard, reddish granite, which, in approaching the hanging, be- 
 comes soft and is traversed by slips or joints. On the hanging- 
 wall itself, A A, there is a seam of tough black clay, in which 
 can be seen frequent films of minutely crystalline blende and 
 galena, and small imbedded shots of ore and rock. This over- 
 
VEIN-WALLS. 
 
 31 
 
 lies a filling of white decomposed granitic material, full of part- 
 ings and seams of black clay, such as C C. The foot-wall, B B, 
 is also marked by a black selvage. Underneath it comes com- 
 paratively fresh " Blue-bird " granite. 
 
 Fig. 24 
 
 -t-^t 
 
 f- 
 
 -f -f 
 
 + "t t-1*. 
 -t- ff* 
 
 s ;.y >1- t -1- 
 
 GRANITE 
 
 SELVAGE 
 
 QUARTZ 
 
 NETTIE MINE, MONTANA. 
 
 A few feet further east this level carried an ore-body, A B 
 in Fig. 24 being the zone so transformed. The brecciated 
 quartz upon the foot-wall was the part of the vein which first 
 became ore. The sides of the drift are now coated with a deli- 
 cate efflorescence of goslarite (sulphate of zinc). In this con- 
 
32 VEIN-WALLS. 
 
 nection it may be of interest to state that in the Gagnon mine, 
 at Butte, three miles away, the apparently clean country, at 
 some distance from the lode, was found* to carry 3 per cent, of 
 zinc, indicating the extent to which the mineralizing action had 
 penetrated. 
 
 Figs. 25 and 26 represent an interesting piece of evidence. 
 Fig. 25 is an attempt to reproduce in color a block of ore giv- 
 ing a section of the Jumbo vein, and broken in the Enterprise 
 mine a year ago. It is a beautiful example of ribbon-structure. 
 The general lode arrangement is shown in Fig. 26, from a 
 sketch made November 19, 1894. The vein follows a line of 
 faulting, nearly at right angles across sedimentary beds of alter- 
 nating sandstone and limestone. The extent of the fault is 
 clearly marked by the dislocation of the bed of lime, B B, and 
 its down-throw of about 2 feet on the hanging-wall. The 
 country on the foot has its bedding-planes turned down, while 
 on the hanging the reverse occurs. 
 
 The vein is about a foot wide and is composed of a regular 
 symmetrical arrangement of diverse minerals. The center of 
 the ore is marked by a seam of quartz. The most remarkable 
 feature of the section, however, is that while on the hanging 
 the ore is frozen hard to the sandstone, on the foot there is an 
 actual vacancy separating the ore from the country. This ex- 
 tends for a few feet above the place of the section, and is seen 
 to find its downward termination as soon as the foot-wall pene- 
 trates into limestone, where the contact of the ore and the en- 
 casing rock is only marked by a slight selvage. 
 
 This description will render more intelligible the meaning of 
 the detailed section of the vein presented in Fig. 25, which is 
 intended to portray as accurately as possible the characteristics 
 of the ore-occurrence at the point in the lode marked A on the 
 outline-drawing, Fig. 26. 
 
 The main features are as follows : The western boundary of 
 the vein is fairly straight, dipping, as the vein does, eastward. 
 It is separated from the country-rock, a light-gray medium- 
 grained sandstone, A A, by an actual vacant space, B B, of 
 about half an inch. The edge of the ore nearest the foot-wall 
 consists of an irregular band, C C, of about f of an inch of 
 quartz, speckled with pyrite and chalcopyrite. Toward the bot- 
 
 * According to Mr. C. W. Goodale, the manager. 
 
n si 
 LI 1 1 
 
 > ? 
 
 > 
 
VEIN-WALLS. 
 
 33 
 
 torn this quartz narrows, but becomes clearly defined into a 
 crystalline comb, with teeth at right angles to the vein. 
 
 Then comes a zone, D D, averaging 1 J inches, of pink rhodo- 
 chrosite. This band is broken into by veinlets of quartz, some 
 of which are only branches from the outer seam, C C, while 
 others traverse the rhodochrosite in bluish-gray streaks parallel 
 
 Fia 26 
 
 to the general structure, and are peppered over with particles 
 of pyrites. 
 
 The rhodochrosite band is broken on the right by the irregu- 
 lar outline of the blende and galena, E E, which is about 2 
 inches wide. There are blotches of yellowish " resin-blende " 
 and patches of bluish-black galena distributed throughout a dark 
 and intricate mixture of these minerals. They shade out into 
 the white quartz, F F, which makes a bilaterally symmetrical 
 division in the ore. The dark mass of the sulphides encloses 
 shreds of rhodochrosite having distinct outlines. 
 
 3 
 
34 VEIN-WALLS. 
 
 Along the median line of the central quartz-seam, F F, occurs 
 a succession of geodes, lined not only with crystals of the quartz 
 itself but also with beautiful crystals of stephanite. The latter 
 are seen in irregularly distributed clusters. In the outer quartz 
 there are numerous specks of pyrite. 
 
 The eastern half of the vein presents, in reverse order, an ex- 
 act repetition of the mineral bands just described. The separa- 
 tion between the rhodochrosite band and the outer quartz is 
 more distinct. The dark sulphides also present a cleaner out- 
 line. The outer quartz has its comb-like structure strongly de- 
 veloped, the points of the crystals penetrating into the pink 
 rhodochrosite and their base gradating into the dark-gray sand- 
 stone of the hanging-wall. There is not the slightest selvage or 
 parting of any sort. The quartz is, as the miners say, " frozen " 
 to the sandstone. The latter is marked by clouds of dark min- 
 eral hardly denned enough to be described as dendritic. This 
 feature is traceable to the diffusion of minute particles of pyrite 
 and stephanite. The rock is rich enough to.be classed as ore. 
 
 In interpreting this structure, shall we follow the explana- 
 tions given for the repeating symmetry of the comb-structure of 
 the Drei Prinzen vein,* and accept the theory of successive 
 crystalline growth from the sides of a gaping crevasse ? Or 
 are we to conclude that the mineral aggregates, now forming 
 the ore, were derived by the substitution, bit by bit, of rock in 
 place by material deposited from solutions circulating along the 
 line of fissuring ? 
 
 Do we conceive of veins as formed by the filling of pre-exist- 
 ing cavities, whatever their shape may be, produced by the 
 rupturing of the earth's crust, or do we believe that lodes can 
 be formed without any previously prepared vacant space and 
 simply by the chemical interchange vaguely covered by the 
 term metasomasis ? or, again, do both these explanations find 
 corroboration in the daily observations of the mine ? 
 
 * As drawn by Von Weisenbach in his book published at Leipzig in 1836. 
 Other notable examples of this structure are C. Le Neve Foster's drawing of the 
 Huel Mary Ann lode (in the Transactions of the Royal Geological Society of Corn- 
 wall, vol. xix., 1875), and that of the Carn Marth lode by J. H. Collins (in the 
 Proceedings of the Institute of Mechanical Engineers, 1873). Reference may also 
 be permitted to the writer's four colored drawings of the Eureka, Songbird, Jumbo 
 and Kitchen veins, accompanying a paper en titled " Vein Structure in the Enter- 
 prise Mine," in the Proceedings of the Colorado Scientific Society for 1895. 
 
VEIN-WALLS. 
 
 35 
 
 Walking recently along the railroad grade between Ana- 
 conda and Cripple Creek, in El Paso county, Colorado, I found 
 
 R 
 
 in the sides of two open cuts the testimony transcribed in Figs. 
 27 and 28, one representing a typical dike and the other a typi- 
 
36 VEIN-WALLS. 
 
 cal ore-vein. In both cases the country is the coarse-grained, 
 red granite of the Pike's Peak region. In both the jointing is 
 well developed. The dark dike of basalt in Fig. 27 cuts clean 
 through the red granite. Its boundaries are clear, there is no 
 mistaking the line of separation. Moreover it is evident that 
 the walls have duplicate outlines and that rupturing has sepa- 
 rated them without the destruction of their definition. The 
 throw of the fault-fissure followed by the dike can be seen to be 
 about 14 inches, and its direction is indicated by the arrow. 
 
 Fig. 28, sketched in the immediate neighborhood, illustrates 
 a gold-bearing vein in the same granite formation. Here there 
 is no essential difference between the country and the vein-fill- 
 ing. The latter is altered granite, easily recognizable as such, 
 in spite of its having become granular and soft through the 
 kaolinization of the feldspar. The walls of the vein are ill- 
 defined, the streakiness of the filling being dimly repeated in 
 the encasing rock. The vein-filling assays $2.60 gold per ton 
 at this place, but is richer, without other material change of 
 character, a few rods distant. 
 
 The dike, Fig. 27, is composed of foreign matter filling an 
 evident fissure ; the vein, Fig. 28, is rock in place changed into 
 ore by the removal of some of its constituents and the substitu- 
 tion of new ones. In the former case liquid material rose into 
 the fissure, probably pari passu with its formation. On the 
 other hand, the vein of gold-ore traversing the granite gives no 
 evidence of the occupation of a fissure by the incoming of new 
 material. The ore is granite in place, softened, decomposed, 
 discolored, and impregnated with gold, but still granite, clearly 
 enough. Some liquid -more subtle than molten lava was the 
 vehicle which brought in the minute particles of gold and re- 
 moved the alkali of the feldspar. It was water, circulating 
 for long periods, and patiently searching out its way, which 
 quietly changed the granite into gold-bearing ore. 
 
 Is it necessary in this case, as in that of the neighboring dike, 
 to suppose the existence of an open fault-fissure ? The evidence 
 of a fault along the course of the vein Cannot be discovered with 
 certainty ; nevertheless, judging from analogy and experience, 
 we would certainly believe that the gold has been deposited 
 along a line of displacement. It seems difficult to conceive 
 that any fracturing, such as marks the beginnings of vein-forma- 
 
VEIN-WALLS. 
 
 37 
 
 tion, can take place without some displacement, however slight, 
 of the two opposing rock-faces. Without such dislocation, 
 though it be comparatively insignificant in amount, the fracture 
 is only latent, and can hardly be said to exist. The possibility 
 of a simple rupture, without any shearing movement or relative 
 displacement, cannot be denied ;* but observation underground 
 indicates that, so far as the deposition of ore is concerned, we 
 
 INDIANA VEIN. GILPIN COUNTY. COLORADO. 
 
 have invariably to deal with rupturing accompanied by a rela- 
 tive displacement of the rock-walls. In other words, veins are 
 generally built on fault-lines. The absence of evidence of such 
 movement in a section on one particular plane is not conclu- 
 sive, since the displacement may have been at right-angles to 
 the section. 
 
 * In this connection I would refer the reader to the suggestive paper of Mr. 
 William Glenn on "The Form of Fissure-Walls, as Affected by Sub-fissuring, and 
 by the Flow of Rocks," read at the Atlanta Meeting of the Institute, October, 
 1895, and printed in Trans., xxv., 499. 
 
38 VEIN-WALLS. 
 
 Where a vein cuts across sedimentary rocks, the dislocation 
 may be looked for along the bedding-planes. Such is the case 
 at Rico, in the Enterprise mine already referred to, where the 
 breast of a stope will show a vein traversed by a fracture at right- 
 angles to its walls, and apparently unaccompanied by any dis- 
 location, but further examination will frequently show that 
 there has been a displacement of the country along the dip 
 of the sandstone and limestone beds, in the strike of the vein 
 itself. 
 
 The question here arises, whether the formation of the ore- 
 vein required the existence of an open fissure. In the particu- 
 lar case shown in Fig. 28, the quantity of foreign material within 
 the vein is insignificant in amount ; the " ore " being simply 
 altered rock in place. That this rock became mineralized by 
 the penetration of metal-bearing waters was probably due to 
 the crushing of the granite by an original slight faulting move- 
 ment, presenting facilities for circulation and consequent chemi- 
 cal interchanges. Minute spaces there probably were ; but 
 a clear opening, or a slow crevassing, such as accompanied the 
 formation of the neighboring dike, seems hardly needed. The 
 ribbon-structure of the Enterprise section, in Fig. 25, presents 
 features much more diflicult to explain. 
 
 When Werner and his school attributed the filling of veins to 
 the agency of descending waters, the existence of open fissures 
 at the time of vein-formation was conceivable, because the 
 theory necessarily restricted such operations to the vicinity of 
 the surface. But the acceptance of ascending waters as the 
 main agents of ore-deposition, and the recognition of the condi- 
 tions possible to the formation of large masses of sulphides, at 
 once transferred the laboratory of ore-formation to a deeper 
 horizon ; and the suggestion that veins were filled by the de- 
 position of layers of mineral precipitated from waters passing 
 upward along fissures which were kept wide open during such 
 time as was required for crystalline growth to choke them with 
 ore, was immediately ridiculed by the miner, because his daily 
 experience taught him that the vein once deprived of its filling 
 did not remain open, but was inevitably closed by the pressure 
 of the surrounding rock. In many cases, in the absence of arti- 
 ficial means of support, his mine-workings collapsed, so that 
 where there was once a level wide enough for a man to walk 
 
VEIN-WALLS. 
 
 39 
 
 through, there came to be only a seam of mud enclosed in 
 shattered rock. 
 
 Despite the miner's objection, however, there is evidence 
 that fissures do sometimes occur, which have been sufficiently 
 open to permit the tumbling in of large pieces of rock. Such 
 
 Fig. 30. 
 
 MAMMOTH MINE, ARIZONA. 
 
 an occurrence was observed in connection with certain faults 
 which disturb the Yirginie lode at Roure, near Pontgibaud, in 
 France,* where, at a depth of 164 feet from the surface, a fault- 
 fissure encloses a mass of clayey material containing boulders 
 of a black, soft, and porous rock, which can be identified as 
 
 * See Etude sur les yites metallifZres de Pontgibaud par M. Lodin, Ingenieur-en- 
 chef des Mines. Annalesdes Mines, April, 1892, and " The Lodes of Pontgibaud," 
 by the writer, in Eng. and Min. Jour., August 11 and 18, 1894. 
 
40 VEIN-WALLS. 
 
 pieces of scoriaceous lava. No such rock occurred elsewhere 
 underground ; and the boulders must have been portions of the 
 Quarternary alluvium which covered the outcrop of the lode, 
 and fell into it at the time of its intersection by an open fissure, 
 which long post-dated the formation of the ore-vein itself. The 
 mines are in a district which has frequently been subjected to 
 earthquakes, and in the heart of a region formerly the scene of 
 great volcanic activity. 
 
 We must be careful, however, to distinguish between the for- 
 mation of cavities within the zone of the vadose circulation, and 
 their existence in " the deep," where sulphide ores have their 
 origin. 
 
 Two examples may be quoted. The first is shown in Fig. 
 29, sketched November 25, 1895, in the stopes above the 800- 
 foot level in the Indiana mine, Gilpin county, Colo. The lode, 
 Avhich is the California vein, in its extension westward from the 
 Hidden Treasure mine, is about 2 feet wide. There is no part- 
 ing or selvage separating it from the country. The latter is a 
 quartz-feldspar rock, best described as granulite. Near the lode 
 it is seamed and sprinkled with pyrite, and sufficiently gold- 
 bearing to be sent to the stamp-mill. The main pay-streak is 
 almost entirely composed of black zinc-blende which, by candle- 
 light underground, contrasts strongly with its encasement of 
 light gray country. The upper part of the vein, in this particular 
 stope, consists of a breccia of zinc-blende, with an occasional 
 spattering of wall-rock, the latter so disintegrated as to resemble 
 gravel. At one point, A B, there is a shred of wall-rock lying 
 across the vein. Lower down there are a number of cavities 
 or vugs scattered among angular fragments of ore. It all looks 
 loose, like an old stope filled with ore that has been mined, but 
 the material is hard and difficult to detach without explosives. 
 Lower again, the vein loses both its cavernous and its brecciated 
 character, and consists of a compact body of blende. It may 
 be added that, even where the brecciation is most evident, both 
 walls are lined with a few inches of ore unbroken and firmly 
 attached to the wall-rock into which it gradates. The vugs, 
 when first found, were full of gas (C0 2 , probably) and the 
 miners suffered from bad air when working in ground of this 
 character. The pieces of blende are held together by a siliceous 
 cement, which also covers each fragment in the form of a gray- 
 
VEIN-WALLS. 
 
 41 
 
 blue chalcedonic coating. It is almost certain that the cavities 
 above described contained water, previous to the drainage of 
 the ground by the penetration of the level underneath. 
 
 Fig 31 
 
 ANDESITE BRECCIA fO^| NEPHELINE BASALT 
 
 VEIN MATTER 
 
 THE MOOSE VEIN, CRIPPLE CREEK, COLORADO. 
 
 Another instance is suggestive. In the Mammoth mine, 
 Final county, Ariz., already described, the granite in the east 
 cross-cut at the 300-foot level, north, has an extraordinary num- 
 ber of fissures partially occupied by broken pieces of rock, so 
 wedged in as to leave open spaces. The pieces are not of any 
 foreign rock, but are identical with the enclosing granite. Fig. 
 
42 VEIN-WALLS. 
 
 30 is a reproduction from a sketch made on the spot, March 15, 
 1893. The elongated cavities, such as that illustrated, were 
 found full of water when first reached by the cross-cut ; but 
 they became drained as the workings tapped them, and thereby 
 depressed the water-level of the mine. 
 
 This instance suggests why mining excavations collapse, and 
 yet a natural cavity underground might remain open. The 
 former contains unconfined air only, while the latter may be 
 filled with a confined and practically incompressible fluid, 
 water. 
 
 It is the usual experience in mining that when the abandoned 
 workings of a mine are flooded they are less likely to collapse 
 than when they are dry. This is due partly to the exclusion of 
 air, and partly to the sustaining power of the water itself, as 
 suggested by Mr. P. Argall, in the Eng. and Min. Jour., Sep- 
 tember 23, 1893, p. 314. 
 
 The formation of the hollow spaces occasionally seen in veins 
 is, I believe, in most cases subsequent to the ore deposition, and 
 may therefore have taken place at a time when erosion had 
 brought that portion of the vein near to the surface. The In- 
 diana section, Fig. 29, shows that the cavities have been pro- 
 duced by the shattering of a vein of zinc-blende already formed. 
 The only occurrence of later date is the consolidation of the 
 mass by the agency of water bearing silica, unaccompanied, so 
 far as can be seen, by the deposition of any metallic minerals. 
 In the Mammoth mine, Fig. 30, the blocks of rock wedged 
 within the cavities were coated with crystals of vanadanite and 
 wulfenite ; but there seems to be no connection between the 
 presence of these later minerals and the formation of the ore- 
 bearing parts of the lode. They are the result of secondary 
 processes, of which the upper part of a lode is the characteristic 
 zone of activity. 
 
 The vein in the railway-cut, cited above as a type, presents a 
 filling readily recognizable as simply altered rock containing 
 only an insignificant percentage of material foreign to the com- 
 position of the original granite. Nor is this an abnormal type 
 of vein-structure. The rich gold mines on the adjacent hills 
 afford numerous examples of this very kind of lode-formation. 
 (And incidentally I would say that I know of no mining dis- 
 trict which illustrates modern views on ore-deposition so clearly 
 
VEIN-WALLS. 
 
 43 
 
 as does Cripple Creek.) Of such mines I would quote the 
 Independence vein, whose richness is such as to cause its com- 
 mercial value to obscure its scientific interest. It does illus- 
 trate very aptly, however, this part of our enquiry, because the 
 ore is so very evidently only altered country-rock. In 1893, 
 when the workings had not penetrated far from the surface, the 
 car-loads of ore sent from this mine to the Denver smelters 
 gave the impression that some one had blundered and either 
 shipped waste from a cross-cut or else switched cars of bal- 
 last into the place of loads of ore. One could see that it was 
 the normal Pike's Peak granite with its big pink feldspar, but 
 
 Fig. 32 
 
 DRUMLUMMON MINE, MONTANA. 
 
 it required a trained eye to note that the mica had been largely 
 removed, leaving small iron-stained patches. It was ore by 
 ourtesy, because there was enough gold present to give it as 
 certain commercial value ; but to the petrographer it was clearly 
 granite, not much altered and but slightly mineralized. 
 
 The vein leaves the granite and, going northward, penetrates 
 into andesite breccia. Its character remains the same ; the ore 
 is still altered country-rock ; only now it exactly reproduces the 
 structure of its new encasement, and the habit of the andesite 
 breccia is quite evident, although blotches of sylvanite and fluo- 
 rite may occasionally try to obscure it. The strike of the vein, 
 its width, its richness, all appear unaffected by the passage from 
 one formation into the other, while the change in the structure 
 of the ore is so marked as to render it easy for the observer to 
 know what is the enclosing rock without looking at the walls. 
 
44 VEIN-WALLS. 
 
 In a case such as this and it is not abnormal it is not ne- 
 cessary to suppose the original existence of an open cavernous 
 fissure since the material of the vein is the material of the rock 
 which was there before vein formation began. The vein follows 
 a line which became a path for metal-bearing waters. Minute 
 interspaces there probably existed, such as would be produced 
 by the crushing and slight dislocation of particles of rock lying 
 along a line of fracture ; but a clear opening, a crevassing, such 
 as accompanied the origination of the dike, seems hardly 
 needed. 
 
 Occasionally, it is true, we do find veins ful] of minerals for- 
 eign to the encasing rock and so symmetrically arranged in 
 bands having a comb structure as to suggest to many investi- 
 gators that they were formed by successive crystalline growth 
 from the walls of a vacant fissure. Such, no doubt, would be 
 the interpretation given to the section of vein illustrated in Fig. 
 25. The reversed repetition of the quartz, rhodochrosite and 
 sulphides is evident enough ; but the most striking feature to 
 me is the equal width of each of the two bands of the same 
 mineral. Each vein of mineral would seem to have been frac- 
 tured exactly in the middle previous to the deposition of the 
 next succeeding one. 
 
 This specimen, and numerous similar structures in the same 
 mine, indicate that the rhodochrosite was the first laid down, 
 replacing, in part at least, the crushed rock which encased an 
 original line of fault-fissuring. Subsequently another fracturing 
 occurred, and this time the line of least resistance was the rho- 
 dochrosite itself, which, being homogeneous, broke down its 
 center. The shattered carbonate offered an easy prey to the 
 sulphide-bearing waters which laid down the blende and galena. 
 The presence of bits of rhodochrosite within the sulphide band 
 indicates that the substitution was irregular. Later, new dis- 
 turbing forces were at play and the vein was fractured not only 
 along its middle, as heretofore, but also along the lines of its 
 contact with the encasing rock. These fractures were healed 
 by the deposition of quartz, accompanied first by iron and cop- 
 per pyrite, and then by rich silver-bearing minerals, such as the 
 stephanite. The corrosion of the sandstone on the hanging had 
 on that side irregularly widened the vein so as to give it greater 
 strength; therefore the next movement, the last, took place 
 
VEIN-WALLS. 
 
 45 
 
 along the foot-wall. This apparently resulted in nothing save 
 the crushing of some of the encasing rock and the formation of 
 a selvage whose removal produced the cavity which was so 
 striking a feature of the stope. 
 
 Another typical illustration of this structure is presented by 
 the Amethyst Last Chance vein (at Creede, Colo.) which is cer- 
 tainly a magnificent example of an ore-break.* The country- 
 rock, trachyte, has undergone multiple fracturing and ore has 
 
 Fig. 33. 
 
 NATURAL SIZE 
 
 DRUMLUMMON MINE, MONTANA. 
 
 been deposited along the division-planes so that there are walls 
 ad libitum. The regular ribbon-structure produced by the de- 
 position of agatized quartz in a sheeted rock is very beautifully 
 marked, and the same process of silicifi cation is further evi- 
 denced in those places where the lode consists of breccia com- 
 posed of pieces of country covered by concentric layers of agate. 
 The lode itself is much wider than the pay-streak of silver-ore, 
 ^hich usually follows the foot-wall. On the hanging the boun- 
 dary between vein and country is fairly discernible ; on the 
 foot less so, because for several feet beyond the ore there is a 
 red jasper oid which gradates into country. 
 
 * At Red Mountain, in Ouray county, Colo., it has been the practice to speak 
 of the veins (the Guston, Yankee Girl, and other celebrated lodes) as ''ore- 
 breaks," a break in the rock accompanied by ore a term, it seems to me, much 
 preferable to "fissure vein." 
 
46 VEIN-WALLS. 
 
 In the Enterprise example, Figs. 25 and 26, each succeeding 
 fracture occurred in the mineral deposit which had healed the 
 previous fracture. In other instances the mineral deposit ap- 
 pears to have proved harder than the encasing rock and the 
 second fracturing took place near the original one, but in the 
 soft rock rather than in the hard vein, thereby producing a 
 new break parallel to the first one, and close to it, causing a 
 repetition of vein-walls such as have already been described in 
 connection with the sections given in Figs. 1, 9, 10, 15 and 21. 
 Or there may be the production of companion-fissures forming 
 contemporaneous veins, such as are shown in Figs. 13 and 19. 
 Finally, the companion-fissures may be so multiplied as to cause 
 a sheeting of the country and the formation either of one vein 
 and several, subordinate, smaller and parallel to it, as in ~No. 15, 
 or of a series of ore-streaks united by mineralized country so 
 as to form one large lode, as seen in Figs. 5, 14, 17 and 31. 
 
 The evidence of a multiplicity of fracturing, whether succes- 
 sive or contemporaneous, is the clue, I venture to believe, to 
 many of the anomalies of vein-structure. No district within 
 my knowledge so well illustrates this aspect of the inquiry as 
 Colorado's new El Dorado, Cripple Creek, in El Paso county, 
 where gold-veins occur as mineralized and enriched portions of 
 dikes, phonolite and basalt, traversing masses of andesite tuff 
 and breccia. Other types are observable, but these are to-day 
 the most characteristic. The mineralized rock forming the 
 vein and that less distinctly gold-bearing country which encloses 
 it, have been subjected to such multiple fissuring as to produce 
 a very marked division of the rock into parallel bands or sheets 
 which may be a fraction of an inch apart or several yards. 
 This structure can be seen no less in hand-specimens than in 
 blocks an acre big. The Moose vein, on Raven hill, is a fair 
 example. It is illustrated in Fig. 31, as seen October 27, 1895, 
 in the back of the sixth (or 350-foot) level. A is andesite tuff 
 and breccia, B C D is a dike of dark, blue-gray nepheline basalt, 
 subdivided into two barren parts, B and C, and one ore-bearing 
 portion, D. Native gold and telluride compounds (sylvanite and 
 calaverite) occur along the seams in the basalt where it is de- 
 composed and iron-stained. The pay-streak extends from E to 
 F, about 10 inches. 
 
 This sheeting or multiple fissuring was probably the result of 
 
VEIN-WALLS. 47 
 
 shrinkage accompanying the cooling of the volcanic rock. The 
 fractures have a contemporaneity of origin quite distinct from 
 the successive ruptures discussed in connection with the ribbon- 
 structure of the Enterprise section. The latter were marked 
 by the precipitation of diverse minerals, while those of a Cripple 
 Creek vein are characterized by a similarity of mineral de- 
 position. 
 
 Cases also occur where there can be discerned a combination 
 of both these types of multiple lissuring. 
 
 A line of weakness, or even a region of weakness, once de- 
 veloped in the earth's crust is apt to continue to be a line of 
 least resistance available for future fracturing. Even when a 
 quartz-vein is formed along a line of rupture, healing the break 
 and strengthening it with a substance harder than the rock- 
 walls themselves, we may suppose that the next break will take 
 place along the line of weakness presented by the imperfect co- 
 hesion existing along the plane of contact between the hard 
 quartz and the less resisting rock. 
 
 The gradual penetration of mineral solutions into the imme- 
 diately encasing country may finally obliberate the divisions 
 due to multiple assuring. The sheets of rock separating one 
 from the other would be replaced by ore, and nothing might re- 
 main of the original structure save faint partings in the lode, 
 such as are less evident to the eye than to the hand of the 
 miner who instinctively uses them to assist him in breaking ore. 
 
 Thus, I believe, the collection of observations in various 
 mining districts tends to the modification of that idea of clean- 
 cut definition which accompanied the early ideas of vein-struc- 
 ture. The evident contact between two dissimilar rocks, such 
 as is seen along the walls of a dike, will be often found in veins 
 to be replaced by an indistinct gradation from mineralized to 
 unmineralized rock, originally the same but now rendered un- 
 like by the selecting action of chemical solutions. 
 
 We are justified, however, in putting some limit to the depth 
 of possible ore-formation, since that formation is dependent on 
 the presence of water. The record of the largest number of 
 careful observations has shown that as we sink into the earth 
 the increment of temperature is 1 F. per each 48 feet of de- 
 scent. At this rate the critical point of water would be reached 
 at 34,704 feet or 6J miles from .the surface. Where the tern- 
 
48 VEIN-WALLS. 
 
 perature is that of the critical point (773 F.) water cannot ex- 
 ist as a liquid no matter how great the pressure, but becomes 
 dissociated into its gaseous elements. Moreover we are war- 
 ranted in believing that the thermometrical gradient becomes 
 more rapid at depths beyond those reached by human observa- 
 tion because of a decreased conductivity in the rocks, or as Pro- 
 fessor Prestwich, the best authority on these matters, puts it :* 
 
 " Taking into consideration the probable limitation of the percolation of water, 
 and the possible diminution of conductivity with increase of depth, if there should 
 be any alteration in the thermometric gradient, at great depth, it will be more 
 likely to be in the direction influenced by these more or less certain factors." 
 
 Therefore, taking these conditions into consideration, we may 
 expect the circulation of water to cease at 20,000 feet or there- 
 about. But at the maximum depth the maxima of temperature 
 and pressure must obtain. It must necessarily be a horizon of 
 solution. Precipitation would hardly begin until a lowering of 
 the temperature and a lessening of pressure permitted it. The 
 deposition of ore is the direct result of precipitation, therefore 
 actual ore-formation is likely to be limited to a depth often of 
 15,000 feet. 
 
 It is not difficult to surmise why clean-cut fractures are not 
 necessarily most favorable to ore occurrence. In the Drum- 
 lummon mine, Montana, the distribution of the ore appears to 
 be connected with the change in the angle of intersection be- 
 tween the course of the veins and the strike of the slate country. 
 Most of the ore-bodies have been found where the course of the 
 veins (N. 15 E.) cuts the slates at an oblique angle and the 
 levels run out of ore when their direction is either at right an- 
 gles to, or conforms with, the strike of the country (N. 17 W.). 
 
 Fig. 32 is a sketch made in one of the surface-workings of that 
 mine which illustrates in miniature the fact above noted It rep- 
 resents a small quartz-seam 2 inches wide, traversing the slates, 
 whose structure is very clearly marked by the color bands fol- 
 lowing lines of original sedimentation. Near the left of the 
 sketch the quartz follows a joint and becomes narrowed, while 
 where it crosses (along a line of slight dislocation) the country 
 it has irregularities and bulges which answer to the alternating 
 slate-bands. A rough, ragged fracture, when continuous, may 
 
 * Controverted Questions of Geology, by Joseph Prestwich, D.C.L., F.R.S., etc., 
 Macmillan, 1895, p. 247. 
 
VEIN-WALLS. 49 
 
 be expected to ofter more surface to solvent action and more, 
 but not too many, obstacles to a rapid circulation of under- 
 ground waters. Its structure also means more opposition to 
 the closing in of the walls, because the irregular faces of the 
 fracture, when they come together, leave openings which, if not 
 along one section then along another, have intercommunica- 
 tion, and so permit of a passage which would be badly im- 
 peded, if not absolutely stopped, by the closing in of smooth 
 walls. 
 
 Fig. 33 represents, to actual scale, a piece of slate enclosing a 
 quartz-vein, which came from near the end of the 700-foot level, 
 also in the Drumlummon mine. It so happens that this is a 
 true illustration in miniature of what the lode itself is doing at 
 this point. The New Castletown lode, on which the level is 
 driven, is at this point cutting at right-angles across the bedding 
 of the slates and is barren of ore. In the hand specimen, re- 
 produced in the drawing, a quartz-vein, not quite half an inch 
 wide, cuts perpendicularly across the slate whose bedding is 
 rendered beautifully marked by dark bands. The vein has a 
 uniform width, it has regular well-defined walls guiltless of the 
 projections and bulges noticed in the previous illustration. It 
 may be only a convenient coincidence, but it is a fact that the 
 quartz in Fig. 25 was opalescent and destitute of other miner- 
 als while that in Fig. 24 was true ferruginous vein-quartz. 
 
 Thus underground work bears daily testimony to the close 
 dependence of ore-occurrence upon the geological structure of 
 the enclosing country, a relation, the importance of which Mr. 
 S. F. Emmons has done invaluable service by clearly stating in 
 more than one of his contributions to the Transactions. Want- 
 ing a proper understanding of the structure of the rock enca- 
 sing his vein, the miner gropes but blindly in a maze of tangled 
 phenomena until the geologist, by their proper elucidation, 
 gives him a light which dissipates much of the darkness ob- 
 scuring his progress underground. * 
 
Subject to Revision. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 TEE BENDIGO GOLD-FIELD. 
 
 BY T. A. RICKARD, ALLEMONT, ISERE, FRANCE. 
 (Glen Summit Meeting, October, 1891.) 
 
 AMONG the names which won a world-wide fame during the 
 golden age of the early fifties, Bendigo and Ballarat were to Aus- 
 tralia, what the Yuba and Grass Valley were to California. The 
 map of Victoria did not for a long time show the name of old Ben- 
 digo;* for this first and more distinctive name was replaced with 
 the more English Sandhurst, just as the alluvial diggings gave place 
 to quartz mining. Towards the close of last year, steps were taken 
 to give back the old name, as associated with the early days of rich 
 alluvium, and more suggestive than the application taken second- 
 hand from an English military academy. 
 
 HISTORY. 
 
 The first discovery of goldf in this district, was made in the 
 autumn of 1851 ; but there has never been any certainty as to the 
 day or the man. At that time the country around Bendigo Creek was 
 a part of the Ravenswood sheep-run, and its resemblance to the 
 Forest Creek district (now Castlemaine), induced the first prospect- 
 ing. It was late in November when the "rush" broke out; the 
 shepherds left their flocks ; the sylvan solitudes were disturbed by 
 
 * The name of Bendigo is said to have been derived from a hut-keeper on the 
 Ravenswood sheep-rnn, who on account of his fondness for " fisticuffs '' was nick 
 named Bendigo, after the prize-fighter of that name. It is not aboriginal, as is 
 often supposed, but Spanish ; and equivalent to our Benedict. There must always 
 be some confusion between the two names of Sandhurst and Bendigo; the town, and 
 with it the gold-field, having been three times named. Several other old familiar 
 names have been likewise unfortunately replaced by second-hand English ones; so 
 that an old digger talks of Forest Creek when he means the modern Castlemaine, 
 Mt. Ida for Heathcote, Growler's Creek for Bright, etc. I shall use the names 
 Sandhurst and Bendigo interchangeably. 
 
 t The first discovery of gold in Australia, was made by E. FT. Hargraves, February 
 12, 1851, near Bathurst in New South-Wales. In August of the same year the dis- 
 covery at Buninyong, near Ballarat, inaugurated the first of a series of rushes to 
 the Victoria gold-fields. 
 
 1 
 
2 THE BENDIGO GOLD-FIELD. 
 
 the voices of the first "diggers ;" the green glades of Bendigo .Creek 
 were ruthlessly uptorn by pick and spade ; and the busy energetic 
 life of a young and thriving mining camp replaced the sleepy idle 
 routine of an out-of-the way sheep-station. 
 
 Since that date the gold-field has yielded over fifteen million 
 ounces of the precious metal, valued at more than sixty millions 
 sterling. Like most mining districts, it has passed through days of 
 severe depression and extreme inflation. Until 1854 the alluvium 
 only was worked. The pan and the cradle early gave way to the 
 paddling-tub, a machine more suited to the clayey character of the 
 wash. By reason of the limited supply of water, the long torn was 
 never very widely used. The highest output on record was reached 
 in 1853, when 661,729 ounces, valued at 2,646,800, were obtained 
 from the alluvium only. Long before the diggers were aware of the 
 real value of gold-quartz, they used to amuse themselves by break- 
 ing off specimens from the outcrops for decorative purposes.* Dia- 
 mond Hill owes its name to the beautiful specimens which its surface 
 yielded in the* early days. Vein-mining or " quartz-reefing" had 
 its inception with the discoveries made by Ballestedt on Victoria 
 Hill, which has now been pierced for a depth of over half a mile, 
 and is honeycombed with deep workings. From 1854 to 1862, the 
 quartz-mining industry had a chequered career; as will be readily 
 understood when the peculiar character of the ore-deposits has been 
 passed in review. In 1859 the first regular registration of a quartz- 
 minef took place. About this period the shallow alluvial deposits 
 became exhausted and, in the absence of deeper channels, the whole 
 energy of a very enterprising community was concentrated upon the 
 exploitation of the quartz-lodes. In 1862 the first limited-liability 
 company was brought out; and in the immediately succeeding years 
 the steady development of the field and the increasing knowledge of 
 the lode-structure were accompanied by an increasing gold-output, 
 which rose in 1870 to 241,380 ounces. The formation of numerous 
 companies which marked the early seventies, introduced fresh capi- 
 tal into the district, and thus led to great increase in the work done 
 in the mines, the output from which averaged at this time over 
 300,000 ounces per annum. But company-promotion soon devel- 
 
 * So ignorant, it is reported, were the pioneers of gold-mining in those days, that 
 many immigrants went to the rushes or mining stampedes with the idea that " gold 
 in quartz" meant gold in quarts or pailfuls! 
 
 f This was the Johnson's gold-mine, which is still a rich producer, having 
 headed the dividend list for 1890 with 30,800. 
 
THE BEXDIGO GOLD-FIELD. 
 
 oped into a mania which rapidly did its evil wo r k. Paper mining 
 replaced honest work, as it has done in many another mining district 
 before and since. A reaction set in ; the gold-field saw its darkest 
 days; and a collapse took place which ended the wild speculation in 
 bogus companies and marked the commencement of a new era of 
 steady progress. The opening up of deeper ground and a renewal of 
 
 Fig. 
 
 
 Lradley $ Poates Sngrs. A'. Y. 
 
 SCALE. t50 MH.ES 
 
 :C*j VOLGA NIC 
 
 HJQRANITE 
 
 GEOLOGICAL SKETCH MAP 
 
 OF A PORTION OF 
 
 VICTORIA. 
 
 rich discoveries, brought about a revival in the first years of the last 
 decade, which, accompanied as it has been by great enterprise, and 
 the intelligent development of the mines with a more accurate 
 knowledge of their ore-deposits, has enabled the Bendigo gold- 
 field to hold the first place among the quartz-mining districts of 
 Australasia, and to make its record unique in the statistics of this 
 industry. 
 
4 THE BENDIGO GOLD-FIELD. 
 
 To the members of the Institute, probably few mining districts are 
 less known, considering their importance, than those of the colony 
 of Victoria. The steamship, the railway, and the telegraph, have 
 linked together the most distant mining centers, Broken Hill and 
 Virginia City, Johannesburg and Grass Valley; but the older gold-, 
 fields of Australia have received but a superficial and passing notice 
 from the pens of standard writers. More particularly is this true of 
 Sandhurst or Bendigo,* which shares with Ballarat the first rank 
 among the Australian localities of quartz-mining. This mining 
 center and its peculiar ore-deposits it is my purpose to describe, 
 from the notes of a recent examination. The time three mouthsf 
 was insufficient to enable me to give to the field the extended study 
 which it invited; and I would leave the subject to better hands, did 
 I not believe that the objects of our Institute are best carried out, 
 when its members place on record the different facts observed in 
 different countries, in order that a mass of observations may ulti- 
 mately be accumulated, which those best qualified may combine and 
 discuss. 
 
 GENERAL DESCRIPTION. 
 
 At the outset a general description of the appearance of the gold- 
 field may be of interest. A very good view can be obtained from 
 the upper platform of the Old Chum poppet-heads,! on Victoria 
 hill. The air is usually clear, and from this point of vantage one 
 can see a long way. The district lies among a series of undulations 
 which rise above the tame level of the surrounding plains. The 
 even line of the latter is further broken by several hills, marking the 
 granite bosses which penetrate the overlying slates and sandstones. 
 To the north, poppet-heads and tall red brick chimneys in long suc- 
 cession indicate the various great lodes or " lines of reef," stretching 
 out to Eaglehawk, four miles away, while out in the distance be- 
 
 * Only the more recent works on gold-deposits contain any references, and these 
 are almost invariably inaccurate and misleading in their descriptions of the mode 
 of occurrence of the quartz. Lock's Gold which is, generally speaking, a very 
 complete compilation on the subject, contains only one reference to Sandhurst, 
 comprised within a paragraph of a dozen lines. 
 
 f April, September, and part of October, 1890, also a part of February, 1891. 
 % " Poppet heads" is the English and colonial equivalent for the Western "gal- 
 las " or gallow's frame. " Three legs " and " heapsteads " are the names used in the 
 north of England. 
 
 \ A " line of reef" is a reef or lode taken as a whole. The mines of Amador, 
 Calaveras, and Tuolumne counties would be said to be on " the same line of reef," 
 viz., "the Mother-lode" of California. 
 
THE BEXDIGO GOLD-FIELD. 
 
 yond is the dark blue sea of the trackless bush,* broken in front by 
 the hills at Kerang and to the right by the promontory of the White 
 hills,t a name familiar to every Australian digger. White hills 
 they are no longer, for the "cement" which covered the rich allu- 
 vium has become oxidized, and patches of red gravel-heaps have 
 replaced what was once glistening white. Between these and the 
 spectator lies the modern city of Sandhurst, its well laid out streets 
 lined with the English trees which have replaced the gums that 
 once covered the site. A wavering, blue, irregular line marks Ben- 
 digo creek, once flowing through the forest glades, but now mean- 
 dering past tailing-heaps and back yards. Out beyond the town we 
 
 Fig. 2. 
 
 hVy.V.V.-.ISANDSTONE |^=g=j SLATE 
 
 SADDLE. 
 
 QUARTZ. 
 
 can dimly see Mt. Ida, where Heathcote lies. Southward the suc- 
 cession of poppet-heads marks the auriferous belt. The engine- 
 houses of the South Bellevue and Eureka Extended mines indicate 
 the Xew Chum reef, on which there is operated to-day perhaps the 
 greatest series of deep gold-quartz mines which the world has yet 
 seen. A new church rises above Golden Square, the scene of some 
 of the first and richest of the alluvial diggings. The view is further 
 diversified by gray heaps of tailings, bluish piles of waste rock, gar- 
 
 * The forest of Eucalyptus, which at one lime covered the whole of the habitable 
 portion of the Australian continent. 
 
 f The White Hills of Bendigo and the Black Hill at Ballarat are in the history 
 of Australian gold discovery what Mokelurane Hill in old Calaveras, and Table 
 Mountain in Tuolumne were to California, or what Ruby Hill at Eureka, and Mt. 
 Davidson at the Comstock were to Xevada. 
 
6 THE BEXDIGO GOLD-FIELD. 
 
 dens and houses, among which is seen the sinuous curve of the rail- 
 way along which the Melbourne express is now coming. Further 
 south, in the distance, are the granitic slopes of Mt. Alexander, be- 
 yond which lies Castlemaine. To the west, clouds of sulphurous 
 smoke indicate the various pyrites-works, and a black line against 
 the blue sky marks the water supply flume, while immediately be- 
 low us are the gardens and house of one of the mine-owners,* an oasis 
 of pleasant green among the stern practical surroundings of mines 
 and mills. 
 
 Sandhurst or Bendigo has a population of over 30,000 inhabitants, 
 several fine public buildings, and some very beautiful public gar- 
 dens. It is connected with Melbourne, the chief port and metropo- 
 lis of Victoria, by a double-track railway 101 miles long, constructed 
 at a cost of 18,000 per mile. 
 
 STATISTICS OF PRODUCTION. 
 
 A few figures, taken from the annual report of the Secretary for 
 Mines, will indicate the size and importance of the Bendigo gold- 
 field. During the past two years the gold-production of the three 
 leading Australian colonies has been as follows: 
 
 Victoria, 1889, . 
 1890, . 
 
 New South Wales, 1889 
 " " 1890 
 
 Queensland, 1889, 
 " 1890, 
 
 The year 1889 was the first in which Victoria did not lead the 
 colonies, being surpassed by Queensland through the Mt. Morgan 
 mine, whose output alone was over 300,000 ounces. The marked 
 decrease in the yield of Queensland for 1890 is similarly due to a 
 decline in the output from Mt. Morgan. The explanation of the 
 Queensland average of 288 per miner, in 1889, is explained by the 
 fact that the most of the value of the product of Mt. Morgan in that 
 year found its way into the pockets of half a dozen men. 
 
 The yield of 588,560 ounces (1890) is the lowest on record in the 
 history of gold-mining in Victoria. There has been a gradual de- 
 crease during the past decade, mainly due to the exhaustion of the 
 more readily accessible alluvial deposits. 
 
 Ounces. 
 
 Value. 
 
 No. of 
 miners. 
 
 Average per 
 miner. 
 
 
 . 
 
 
 . 
 
 s. 
 
 d. 
 
 614,838 
 
 2,459,352 
 
 24,323 
 
 101 
 
 2 
 
 2 
 
 588,560 
 
 2,354,240 
 
 23,833 
 
 98 
 
 15 
 
 7 
 
 119,758 
 
 434,070 
 
 10,192 
 
 42 
 
 11 
 
 9 
 
 127,460 
 
 459,086 
 
 12,182 
 
 37 
 
 13 
 
 8 
 
 737,822 
 
 2,582,377 
 
 8,955 
 
 288 
 
 7 
 
 5 
 
 600,000 
 
 2.100.000 
 
 
 
 
 
 Fortuna Villa, the residence of M. George Lansell. 
 
THE BEXDIGO GOLD-FIELD. 7 
 
 From 1851 to the end of 1890 the yield of gold from Victoria 
 amounted to 56,870,574 ounces, valued at 227,482,296, an average 
 per year of 1,452,761 ounces, the highest for any single year being 
 3,053 r 744 ounces, in 1856. Of this total, Bendigo has contributed 
 11,168,414 ounces, valued at 44,673,656. In addition, it is esti- 
 mated that the gold taken away privately to Melbourne and the 
 neighboring colonies, and not included in the government returns 
 for the district, will amount to 4,000,000 ounces, which would give 
 a round total of over 15,000,000 ounces, valued at over 60,000,000 
 sterling. 
 
 Victoria is divided into seven mining districts, of whfch the 
 
 *i$m 
 
 
 .yV--.X--.lSANDSTONE |=gg^|8LATE frW<i QUARTZ 
 
 FALSE SADDLE. 
 
 most important are Ballarat and Bendigo, the former being the chief 
 alluvial center, while the latter leads the quartz-mining districts. 
 The total area of the Victoria gold-fields, 86,760 square miles, is 
 worked and prospected by a force of 23,833 miners ; and the propor- 
 tion belonging to the two principal gold-fields is as follows : 
 
 Area in 
 sq. miles. Miners. 
 
 Bendigo, . ... * . . . 5,870 4,420 
 
 Ballarat, 5,180 6,249 
 
 While the mining operations in the Ballarat district are distributed 
 over an actual area of 40 square miles, and the boundaries include 
 such important centers as Clunes and Creswick, those of the Ben- 
 
8 THE BENDIGO GOLD-FIELD. 
 
 digo district are practically concentrated upon an area of 21 square 
 miles within the adjacent townships of Eaglehawk and Sandhurst. 
 During the past 2 years the yield of gold has been : 
 
 Alluvial. Quartz. Total. * 
 
 Oz. dwts. grs. Oz. dwts. grs. Oz. dvvts. grs. 
 
 Bendigo, 1889, 6,973 12 10 134,547 8 21 141,521 1 7 
 
 " 1890, 3,293 3 18 134,671 10 11 137,964 14 5 
 
 Ballarat, 1889, 98,342 6 13 117,321 18 215,664 4 13 
 
 " 1890, 92,836 2 10 117,597 8 210,433 2 18 
 
 It is seen that, while Ballarat is the leading alluvial district, it 
 produces also a large proportion of gold from quartz,* while at Ben- 
 digo, on the other hand, the alluvium is relatively important. The 
 figures just given bear out the statement of the Secretary for Mines 
 that the diminution of the gold-yield is chiefly in that from the allu- 
 vial mines. In both the leading centers the yield from quartz has 
 slightly increased, while that from alluvium has considerably dimin- 
 ished. The average yield of the quartz per ton of ore crushed, dur- 
 ing the past year, was as follows : 
 
 dAvts. grs. 
 
 Victoria (average of the seven districts), ..' .9 4 
 Bendigo, . . . , . , . , . . . 9 5 
 
 Ballarat,. ./I . ; U : '. . ; -> : . . . . 7 21 
 
 The average yield from pyrites and blanketings was: 
 
 , Total treated. Total yield. Average. 
 
 Tons. cwt. Oz. dwts. grs. Oz. dwts. grs. 
 
 Bendigo, . . 1,766 10 3,901 16 12 244 
 
 Ballarat, ; . 2,148 5,196 19 7 289 
 
 The highest and lowest prices paid for the gold per oz. were, at 
 Bendigo, 3 17s. and 3 19s., and at Ballarat, 3 17s. 6d. and 4 3s. 
 
 While in the colony as a whole the number of miners is pretty 
 equally distributed between alluvial and quartz mines 11,470 in 
 the former to 12,363 in the latter there is, in the two leading dis- 
 tricts, a greater disproportion ; Bendigo having 949 alluvial and 
 3375 quartz-miners, while Ballarat has 2440 alluvial and 3677 
 quartz-miners. At Sandhurst there are 270 Chinamen, nearly all 
 engaged in surface-washing, while at Ballarat there are 736 Mon- 
 golians to 5508 Europeans. 
 
 * At Ballarat, as the deep leads (alluvial) were becoming worked out, the crop- 
 pings of the quartz-veins were found in the bed-rock of the alluvium. Several 
 claims which have been rich in alluvium are now good quartz-mines. 
 
THE BEXDIGO GOLD-FIELD. 
 
 9 
 
 The Bendigo gold-field includes several scattered subdivisions; 
 but it consists practically of Eaglehawk and Sandhurst (or Bendigo), 
 two distinct municipalities, forming one long straggling township, 
 somewhat after the manner* of Gold Hill and Virginia City, or 
 Black hawk and Central City. 
 
 In 1890 the machinery employed in quartz-mining was thus dis- 
 tributed : 
 
 Sandhurst, 
 Eaglehawk, 
 
 Steam- Machine Concen- Arras- 
 engines. Stamps. drills. trators. tras. 
 
 . 175 625 70 65 25 
 
 105 501 40 40 6 
 
 For the Bendigo gold-field as a whole, the numbers are as fol- 
 
 Fig. 4. 
 
 GARDEN GULLY LINE 
 
 IDEAL SECTION. 
 
 SHOWING THE MAIN LINES OF REEF. 
 
 Bradley & P^.ttt 
 
 Engrt. S. F. 
 
 lows: Steam engines, 316; aggregate nominal, H.P. 6873; stamp- 
 heads, 1328; whims, 76; whips, 127; machine-drills, 128; con- 
 centrators, 105; arrastras, 82. The total value is estimated at 
 478,611. Considering the size and yield of the district, the value 
 of the machinery is small indeed, when compared to that of a 
 Western American mining-camp, with its much larger and more 
 costly hoisting-engines, mills, etc. 
 
 * But the mining townships of Victoria are very different from those of the 
 great West. Ballarat, Sandhurst, Chines, and Creswick are pretty towns, situated 
 in rich agricultural districts, and presenting none of that bare ruggedness which is 
 characteristic of most mining camps of Colorado, Nevada, and California. 
 
10 THE BENDIGO GOLD-FIELD. 
 
 The quantity and cost of the timber consumed for mining pur- 
 poses during the year were as follows : 
 
 Firewood,* . 146,628 tons. 
 
 Props and cap-pieces, 105,533 pieces. 
 
 Laths and slabs, . . . . . . . 80,820 " 
 
 Sawn timber, . ". V 1 . .' ", ''.'.' . 821,232 feet. 
 
 The value of this is set down at 63,856 6s. 6d. 
 
 Mining is carried on for the most part by companies, whose share 
 capital is invariably small and their reserve capital usually nil. 
 The tribute-system is largely in use, and, here as elsewhere, often 
 leads to the discovery of valuable ore-bodies. There are few private 
 mines, the most important of which belong to Mr. Lansell, a mine- 
 owner, the record of whose enterprise forms an important part of 
 the history of the field. A few small parties of miners, less numer- 
 ous than the future prosperity of the district requires, are engaged 
 in prospecting new grounds. 
 
 Operations are distributed among eleven approximately parallel 
 formations or " lines of reef," of which by far the most important 
 are the New Churn, f the Garden Gully and the Hustlers. At 
 present the greatest activity prevails along the first-named which 
 has also been the most continuously profitable of the series. A 
 notion of the extent of the field and its worthiness to -rank among 
 the greatest of modern mining centers may be obtained from the 
 following statements. The New Chum lode has been worked from 
 Axe Creek to the Franklin mine in Sailors' Gully, a distance of 
 fourteen miles. The Garden Gully has been followed from the 
 Suffolk Tribute and the Moon, beyond Eaglehawk, to the Great 
 Southern Extended, beyond Bendigo Creek, a distance of 7 miles. 
 The third great lode, the Hustlers, has been tapped at the Fortuna 
 Hustlers in the city of Sandhurst, and from there has been worked 
 as far as the King of Prussia, in Opossum Gully, which is 5 miles 
 away. So much for the extent of working along the strike. Down- 
 wards, the New Chum has been followed for a vertical depth of over 
 half a mile (2641 feet), the Garden Gully for over 2300 feet and the 
 Hustlers 2000 feet. There are in Sandhurst 18 shafts exceeding in 
 depth 2000 feet. Several of these are still going down ; and of the 
 
 * Fifty feet of firewood equal one ton of 2240 pounds. Laths and slabs are the 
 same as what the American calls " lagging." 
 
 f " New Chum " is the colonial equivalent of the Western " tenderfoot," i.e., a 
 fresh arrival in the countrv. 
 
THE BEXDIGO GOLD-FIELD. 
 
 11 
 
 20 companies among which these 18 shafts are distributed, 3 are in 
 rich ore, 7 are breaking pay-ore, 9 are prospecting and 1 is idle. 
 
 Though the output has suffered during the past two years by 
 reason of the greater attractions presented by gambling in silver 
 shares at Broken Hill, Sandhurst contained during the past year 28 
 dividend-paying companies which produced 101,879 ounces 10 dwts. 
 (not including 7 tribute parties which were dividend paying), 
 enabling the payment of 149,381 17s. in dividends. The work 
 of the past year has shown an improvement as indicated by the fol- 
 lowing comparison. In 1889 the calls amounted to 137,489, the 
 
 Fig. 5. 
 
 dividends to 118,473, a balance on the wrong side of 19,016. lu 
 1880 the calls were diminished to 111,142, while the dividends 
 increased to 149,38,1, leaving a profit of 38,239. During the 
 last 14 years the dividends have exceeded the calls by 1,101, 836, the 
 year 1889 being the only unprofitable period. Roughly speaking, 
 during 1890 each ounce of gold was obtained at a cost of 2 10s. Sd. t 
 leaving 1 9s. 4d as profit for the shareholders. 
 
 Out of the 28 companies which appeared on the dividend-list at 
 the beginning of 1891, the 20 whose records are obtainable show 
 that only four have failed to pay back the capital expended 
 upon them, and of these four, one is not yet a year old. The 
 
12 
 
 THE BEKDIGO GOLD-FIELD. 
 
 average total dividends of each of these 20 properties* amounts 
 to 81,947, the average nominal capital of each is 49,742, 
 while the average paid up capital is only 34,167. It is seen, there- 
 fore, that these 20 companies have returned in dividends nearly 
 twice the amount of capital called up for their equipment and de- 
 velopment. Further, it should be stated that the number under 
 consideration does not include several of the minesf which have the 
 
 * The following list gives the detailed figures of the twenty companies which 
 were dividend-paying at the beginning of this year (1891). The results are given 
 
 up to the end of 1890: 
 
 
 
 
 
 Nominal 
 
 Paid up 
 
 
 Company. 
 
 capital. 
 
 capital. 
 
 Dividends. 
 
 
 . 
 
 . 
 
 . 
 
 Catherine Eeef United, . 
 
 135,200 
 
 82,810 
 
 50,755 
 
 Fortuna Hustlers, . 
 
 14,000 
 
 3,500 
 
 2,800 
 
 Gt. Ex. Hustlers, 
 
 68,000 
 
 62,050 
 
 419,200 
 
 Hercules and Energetic, . 
 
 60,000 
 
 8,250 
 
 74,625 
 
 Johnson's Reef, . , . . 
 
 78,000 
 
 72,100 
 
 223,950 
 
 Lazarus New Chum, . . 
 
 67,500 
 
 63,187 
 
 67,500 
 
 Lazarus No. 1, . . 
 
 67,500 
 
 63,950 
 
 95,062 
 
 Lady Barkly, . . . . 
 
 24,000 
 
 17,400 
 
 58,315 
 
 New Chum Con, . V 
 
 42,000 
 
 18,200 
 
 132,300 
 
 New Chum Railway, . . 
 
 36,890 
 
 28,589 
 
 52,078 
 
 New Chum United, . , 
 
 14,750 
 
 8,850 
 
 66,375 
 
 North Old Chum, . 
 
 54,000 
 
 33,075 
 
 86,495 
 
 Rose of Denmark, . . . 
 
 24,000 
 
 4,800 
 
 63,600 
 
 
 45,000 
 
 27,750 
 
 15,750 
 
 Shenandoah, . , , . 
 
 96,000 
 
 33,600 
 
 59,600 
 
 South New Chum, . . . 
 
 32,000 
 
 21,735 
 
 800 
 
 Specimen Hill United, . 
 
 20,000 
 
 12,000 
 
 23,500 
 
 United Hustlers and Redan, . 
 
 48,000 
 
 19,200 
 
 114,000 
 
 United Devonshire, 
 
 28,000 
 
 9,800 
 
 21,700 
 
 Young Chum, . 
 
 40,000 
 
 32,500 
 
 10,550 
 
 Totals, . . ." 
 
 994,840 
 
 623,346 
 
 1,638,955 
 
 Averages, . 
 
 49,742 
 
 31,167 
 
 81,947 
 
 f The greatest producers have been the following mines : 
 
 Called up 
 
 Name. qp,piial. Dividends. 
 
 . . 
 
 Garden Gully United 21,642 667,796 
 
 Gt. Extended Hustlers, 62,050 419,200 
 
 Johnson's Reef, 72,100 223,950 
 
 Gt. Hustler's Tribute, 61,200 620,200 
 
 North Johnson's, ....'.. 31,850 148,625 
 
 United Devonshire 8,244 224,000 
 
 New Chum Con., 18,200 132,300 
 
 There are many others, the totals of whose dividends is more than 100,000. 
 
THE BEXDIGO GOLD-FIELD. 
 
 13 
 
 greatest records, but have temporarily dropped out of the divi- 
 dend-list. 
 
 The instances of individual productiveness here have been sur- 
 passed in other parts of the world ; but it is doubtful whether in the 
 history of gold-mining there can be shown a better record in the 
 proportion of dividends paid to capital expended. The product of 
 the mines from tribute-parties is not included in the above list unless 
 especially mentioned. It is a matter of record, for instance, that, 
 including the product of the tributers, the Garden Gully United has 
 yielded over 1,000,000. The Kentish mine of the late I. B. 
 Watson is said to have yielded over 2,500,000; and another 
 private mine, G. Lansell's "ISO/ 7 has given magnificent profits to 
 its owner, as have also several tribute-workings, the records of which 
 are not accessible now. 
 
 To the Australian tBe name of Sandhurst is always associated with 
 
 Fig. 6. 
 
 INVERTED SADDLES. 
 
 the "saddle-reefs." It was the frequent mention of these which led 
 me to visit the mines ; and it is the peculiar interest which they must 
 have for all geologists and mining engineers which has induced the 
 publication of these notes. Before discussing, however, these and 
 other matters of detail, a general account of the geology of the 
 district should be given. 
 
 GEOLOGY. 
 
 As will be seen by a reference to the map* of Victoria (Fig. 1) ? 
 the gold-field is situated near the northern edges of the exposure of 
 the Lower Silurian, which, a short distance further north, is over- 
 lain by Pliocene shales. The boss of granite at Mt. Hope suggests 
 
 * The geological map of a portion of Victoria which accompanies this paper, 
 was copied by me from the geological sketch-map in The Geology and Physical 
 Geography of Victoria, by R, A. F. Murray, the geologist of the Victorian govern- 
 ment. 
 
14 THE BENDIGO GOLD-FIELD. 
 
 the deeper masses of crystalline rocks which also form the M Alex- 
 ander ranges, dividing the Sandhurst and Castlemaine gold-fields. 
 The gold-mining districts of Victoria are almost entirely confined to 
 beds of Upper and Lower Silurian age, of which Mr. Murray says :* 
 "As surface or underlying rocks, they occupy the greater part of 
 Victoria from the sea-coast to elevations exceeding 6000 feet." 
 They form the bed-rock of the alluvium the yield of which aston- 
 ished the world in 1851, and the country-rock of the quartz-lodes 
 from which that alluvial gold was derived. Selwynf computed their 
 total thickness to be not less than 35,000 feet. While the line of 
 division between the two horizons has not been found, certain differ- 
 ences in lithological character and fossil remains have led the Vic- 
 torian Geological Survey to refer to the Upper Silurian that portion 
 of the Silurian rocks lying east of a line drawn from Melbourne to 
 Heathcote, while the Silurian west of that line* is regarded as Lower. 
 It is in the lower horizon, which, according to Professor McCoy, cor- 
 responds to the Llandeilo Flags and Bala rocks of Wales, that the 
 auriferous deposits of Ballarat, Castlemaine, and SandhurstJ occur. 
 In the upper are the Ovens district, the Buckland and Harriet- 
 ville. Again, to the latter belong the picturesque alpine districts, 
 and to the former, the extensive plains diversified by low rounded 
 hills. 
 
 While there is a general similiarity in the mode of occurrence of 
 the gold, there are also some interesting differences in the habits of 
 the quartz-lodes in the two horizons. The auriferous deposits are 
 found traversing certain defined belts, which have a general strike 
 20 to 30 west of north. These parallel belts contain veins of 
 quartz which conform to the general strike, and which, like the belts 
 themselves, are separated by barren portions of country. My ob- 
 servations lead me to believe that the gold-veins of the Lower Si- 
 lurian are more often conformable to the stratification, while those 
 of the Upper are more frequently true fissures, traversing the country 
 at an angle to the bedding. R. A. F. ^Murray, the government 
 geologist, has noted that while the quartz-reefs in the Upper Silurian 
 
 * Page 33 of the book mentioned in the preceding note. 
 
 f A. R. C. Selwyn, formerly head of the Geological Survey of Victoria, and now 
 occupying a similar position under the Canadiari government. 
 
 J The fossils most common in the rocks at Sandhurst, are graptolites, particularly 
 stellatus, extensus and tripedes, together with Sertul'iria mayna and vergata, Didymo- 
 grapsus, fruticosus and Phyllograpsus folium. In the weathered slate-beds they are 
 easily found, but underground, the dark color of the rock, and the development of 
 fine cleavage renders them difficult of recognition. 
 
THE BEXDIGO GOLD-FIELD. 
 
 15 
 
16 THE BENDIGO GOLD-FIELD. 
 
 may be fewer in number and smaller in size, they have, on the other 
 hand, considerably exceeded hitherto, in their average yield of gold, 
 the reefs in the lower division.* It seems probable, however, that 
 the smaller number of discovered reefs in the upper horizon is 
 largely due to the more mountainous and less accessible character of 
 the country in which they occur. In the few districts, such as 
 Bright and the Buckland, where there has been any considerable 
 amount of prospecting in the rocks of this division, large numbers 
 of parallel veins have been exposed. Their greater yield per ton 
 *is accounted for by the fact that the ores of the mines in the Upper 
 Silurian are frequently so charged with sulphides as to come under 
 the "refractory" class, necessitating the working of ore of higher 
 tenor than is required in the Lower Silurian, where the quartz is 
 usually of the simplest " free-milling" type. This difference will 
 also serve to explain the circumstance, mentioned by the govern- 
 ment geologist, that all the largest nuggets obtained in the alluvial 
 mines of Victoria have been found where Lower Silurian rocks 
 prevail. 
 
 The Bendigo district consists, broadly speaking, of a belt of sand- 
 stones and slates of Lower Silurian age, abutting to the south and 
 west against the granite of the Mt. Alexander ranges and overlain 
 to the north and northeast by the shales of the Pliocene. The most 
 marked characteristic of these sandstone and slate beds is the extreme 
 bending, folding, and contortion which they have undergone, 
 accompanied, as might be expected, by a varying amount of fissuring 
 and faulting. The anticlinal and synclinal undulations are often 
 remarkably sharp and exhibit every gradation in extent, from a few 
 feet to miles, from a hand-specimen to those larger corrugations of 
 the earth's crust which geologists name " ge-synclines" and ''ge- 
 anticlines." The main anticlinal axes strike N. N. "VV. and S. S. E., 
 but there are also transverse undulations which further complicate 
 the geological structure. 
 
 THE REEFS. 
 The quartz reefs or lodesf conform to these folds in the country- 
 
 * The returns show that the average yield per ton is as follows : 
 
 Upper Silurian, BucWorth, 13 dwts. 23 grs., Gippsland 15 dwts. 21 grs. 
 
 Lower Silurian, Ballarat, 7 dwts. 21 grs., Bendigo, 9 dwts. 5 grs. 
 
 f The Australian calls a quartz lode or vein a " reef," the Californian a " ledge," 
 while in Colorado the word "crevice" often does similar duty. Throughout this 
 article I shall often use the colonial mining terns, since they are usually expressive 
 and it would be difficult to find other names that are not also local. 
 
THE BEXDIGO GOLD-FIELD. 
 
 17 
 
 I . 
 
 Q UJ 
 
 5? 
 
 ZS 
 
 UJ 
 
 I 
 
 CO 
 
18 THE BENDIGO GOLD-FIELD. 
 
 rock, that is, the ore-deposits lie between and along the beds of slate 
 and sandstone, the anticlinal axes of which form the apex or cap of 
 the quartz-formations, which are thus known as "saddles," while 
 the lower portions, called the " legs," similarly dip east and west 
 with the inclosing strata. In like manner, in the direction of their 
 strike, the quartz-formations* pitch north and south conformably to 
 the longitudinal undulations produced in the anticlinal axes by the 
 transverse folds mentioned above. 
 
 The " saddle-reef" is the distinctive ore-deposit of the Sandhurst 
 mines. The references to this most beautiful type of ore-deposit to 
 be found among the works relating to the distribution and extraction 
 of the precious metals, are both meager and inaccurate. In the 
 Colonies, it is true, one hears a great deal of these " Sandhurst sad- 
 dles," such references being, however, for the most part very vague, 
 and incorrect. In other mining districts, in the neighboring colo- 
 nies of New South Wales, Queensland, etc., the writer has often 
 heard this or that mine spoken of as containing "a saddle, just like 
 those of Sandhurst." On examination these proved in every case to 
 be different forms of the ordinary junction of two lodes, not true an- 
 ticlines, producing however bodies of quartz which the old Bendigo 
 digger would promptly label as "saddles," for the sake, perhaps, of 
 auld lang syne. I was beginning to fear that the saddle-reef as a 
 distinct formation did not exist at all, even at Sandhurst, until 
 underground, at the New Chum and Victoria mine, I saw for the 
 first time a type of ore-deposit which is perhaps the most interesting 
 of the many forms in which gold is known to occur. I remember 
 well my delight in recognizing the peculiar character of the lodes, 
 also my disappointment on finding that the " west legs" did not 
 conform to the bedding, and then finally my relief when I saw that 
 in the latter observation I had confounded bedding and cleavage. 
 The cleavage in some parts of the field is so strong as to obliterate 
 the bedding; and it is by reason of this fact that so many observers 
 have gone astray In what is practically the only authority dealing 
 with Victorian mining Brough Smyth's Gold-Fields of Victoria 
 there is a lamentable confusion upon this point. The difficulty is 
 further increased by the fact that there are "false saddles," one leg 
 
 * In the mines, the words "pitch," "dip," "underlay," etc., are used indis- 
 criminately. I shall always use "dip " to express the angle with the horizon, east 
 or west, made by the beds of the country or the reefs which are conformable to 
 them. "Pitch" will be used to describe the inclination north or south along the 
 strike of the quartz-formations. 
 
THE BEXDIGO GOLD-FIELD. 
 
 19 
 
 of which conforms to the stratification, while the other follows a 
 joint or some other cross-fracture in the country. Figs. 2 and 3 
 serve to illustrate the simplest type of true and false saddles. In 
 both cases the bedding-planes are indicated, while, to avoid con- 
 fusion, the lines of cleavage are omitted. In Fig. 2, A would be 
 called the cap or apex, B the west leg, and C the east leg. A cross- 
 cut passing through D would be said to be in " center-country ;' 7 ns 
 soon as the dip of the beds became distinctly east or west the cross- 
 
 NEW CHUM 
 
 cut would have penetrated into "east " or " west country." In Fig. 
 3, A A illustrates a fissure, sometimes a fault, sometimes only a 
 joint ; D D is the ore formed along this line of fissure, while B is 
 the body of quartz formed at its junction with the bedding-plane 
 C C, which carries another vein of quartz. When a formation like 
 this is further complicated by a few minor faults and the develop- 
 ment of a strong slaty cleavage at varying angles, it is very diffi- 
 cult to determine correctly the true facts of the case ; and the quartz- 
 body may be mistaken for a true saddle, that is, an anticline of 
 quartz. 
 
20 
 
 THE BEXDIGO GOLD-FIELD. 
 
 The mines are located along the various " lines of reef," which 
 are coincident with the surface-exposure of the quartz formed along 
 the anticlinal axes. The general dip of the country (as distinguished 
 from that of the individual beds comprising it) is eastward; or, as 
 the miners put it, " center-country dips east." The following state- 
 ment illustrates this point. Three mines (they happen to be three 
 famous producers) are taken approximately opposite each other on 
 the three great lines of reef the New Chum, the Garden Gully, and 
 the Hustlers. In the accompanying table, the third column gives 
 the average strike of the anticline which forms the "line of reef," 
 and the fourth the pitch of the quartz-formation at the depths indi- 
 cated in the brackets. The last column gives the dip of " center- 
 country " as determined from the figures given in columns 5 to 8. 
 Taking the saddle as similar to the roof of a house, the third column 
 gives the angle which the ridge makes with the meridian ; tHe fourth, 
 the angle with the plane of the horizon; and the last column, the in- 
 clination of its axis when it is slightly tilted to one side. 
 
 Table showing the Principal Features of the Main Saddle- Formations. 
 
 SHAFT. 
 
 CIH* 
 
 O 
 g 
 
 
 
 M 
 
 B 
 
 CO 
 
 o 
 
 " s 
 'E. '-3 
 
 II 
 
 43 
 
 I 
 
 Distance of 
 nter-country 
 rom Shaft. 
 
 "a 
 
 ill 
 
 verage dip. 
 
 
 3 
 
 < 
 
 
 3 
 
 8 
 
 Q 
 
 o 
 
 < 
 
 "180" Mine 
 
 New Chum... 
 
 21 e W.ofN. 
 
 1 in 6 (at 2500 ft.) 
 
 MO 
 
 5ft.W. 
 
 2500 TOft.E. 
 
 Iinl4 
 
 Victory and Pandora 
 
 Garden Gully 
 
 25 W. of N. 
 
 Iin6 (at 650 ft.) 1 140 
 
 9 i( " 
 
 2160 130 " " 
 
 1 in 15% 
 
 Gt. Ex. Hustlers 
 
 Hustlers 
 
 35 W ofN. 
 
 1 in 5 (at 1800 ft.) 
 
 200 
 
 80 " " 
 
 1800160" " Iin6> 
 
 1 
 
 At the " 180" mine, for instance, the strike of the Chum forma- 
 tion is 21 W. of N, the pitch of the saddle at the 2500-foot 
 level is northward 1 in 6, the dip of center-country is east about 1 
 in 14. The last is determined thus: at the 560-foot cross-cut the 
 center country is 65 feet west of the shaft, while at the 2500 it is 
 70 feet east of the shaft, so that it has travelled eastward 135 feet 
 in about 1940 feet, the general dip of the country having taken from 
 one side to the other of this particular shaft the series of beds inter- 
 sected by it. The ideal section, Fig. 4, represents the structure, and 
 shows how, the general trend of the country being to the east, any 
 one of the deep mine- workings will intercept, in succession, many 
 saddles, some of which will prove gold-bearing and some barren. 
 It will be tunderstood that only the gold-bearing ones of the series 
 
THE BEXDIGO GOLD-FIELD. 
 
 21 
 
 are developed in a manner permitting their proper examination. 
 One mine may have only two gold-bearing saddles, while another 
 may have exposed a dozen or more.* As soon as one formation has 
 been worked out, when the legs intercepted by the deeper cross-cuts 
 are found to become too small or too poor for profit, prospecting is 
 renewed until another gold-bearing saddle is cut. Its apex may 
 occur between the lower portions of the legs of the last saddle or it 
 may not be found for 200 or 300 feet deeper. Deeper, not further 
 east or west on the same horizon ; for the working of the mine has 
 
 Fig. 13 
 
 222 AND LAZARUS. 
 
 shown that a gold-bearing succession of saddles will go down in 
 step-like gradations, each succeeding one being slightly eastward of 
 the one above it (see Fig. 5). This simplicity of arrangement is, of 
 course, much complicated, sometimes utterly destroyed, by faulting, 
 and by the formation of irregular bodies of quartz that may be rec- 
 ognized occasionally as imperfect saddles. 
 
 * In the New Chum and Victoria mine, for instance, as many as 30 saddles 
 have been passed through from the surface to 2300 feet. In the "180" mine, five 
 have been discovered and explored, of which number three have proved profitably 
 auriferous. 
 
22 THE BENDIGO GOLD-FIELD. 
 
 As would be expected by the geologist, these anticlines alternate 
 with synclinal undulations; but this fact has been recognized by few 
 of those engaged in the development of the field, though it is a point 
 of paramount importance to the proper conception of the mode of 
 occurrence of the quartz. The explanation of this neglect is that 
 exploration has been confined, particularly in the deep mines on the 
 New Chum reef, to a narrow strip of country in the immediate 
 vicinity of the great anticlinal axes; and, though it is known that 
 quartz lodes occur, for instance, between the New Chum and Garden 
 Gully lines, these " side-lines," as they are called, have been 
 neglected,* and it is in that portion of the country that the synclines 
 would be situated. Where extensive faulting has taken place, these 
 synclines are to be seen in the workings of some of the mines on the 
 main "lines of reef." In the Confidence Extended, for instance, I 
 observed some small " inverted saddles," as also in the Hercules and 
 Energetic. In both cases there is reason to believe that a dislocation 
 has brought a portion of the west country into line with one of the 
 chief anticlinal axes, in the one case the Garden Gully, in the other 
 the New Chum. A good instance of the more frequent occurrence 
 of " inverted saddles " is presented by the Great Britain mine, located 
 on the Carshalton reef, a "side-line" west of the New Chum. Fig. 
 6 illustrates it. 
 
 The distribution of the gold in the quartz of the saddle-reefs 
 shows great variations. In a given formation in one mine the cap 
 or a portion of the cap only will pay, while on the same formation 
 in a neighboring claim the cap and west leg may yield good returns, 
 or again both legs may prove gold-bearing while the cap is barren. 
 The quartz-bodies do not extend uninterruptedly along their strike ; 
 their continuity is broken by overlappings or disturbed by faults. 
 Different local changes in the structure of the country give very 
 different shapes to the enclosed formations. 
 
 The most extensive ore-body and the greatest yield of gold from 
 any one formation is claimed by the Garden Gully line from a saddle 
 which traversed a group of mines (of which the Garden Gully 
 United and the Victory and Pandora were the chief producers), at 
 
 
 
 * Since writing the above, and during a later visit to Sandhurst, I learn that the 
 recent legislation as to mining on private property, together with the notable suc- 
 cess of the New Red, White and Blue Consolidated, which is on a "side line" (the 
 Sheepshead), has caused the beginning of active exploration on these subsidiary 
 formations, this exploration being due, as has often been the case in this gold-field 
 to the enterprise of Mr. Lansell. 
 
THE BENDIGO GOLD-FIELD. 
 
 23 
 
24 THE BENDIGO GOLD-FIELD. 
 
 a depth of from 600 to 700 feet from the surface. In the Garden 
 Gully United alone, it was worked for 646 yards along the strike 
 during 14 years, and yielded 13 tons of gold. For continuous pro- 
 ductiveness, most numerous succession of gold-bearing formations, 
 and greatest underground development, the New Chum ranks first. 
 One can walk underground from the Victoria Consols to Golden 
 Square, through the continuous workings of 21 mines, at a depth of 
 from 1800 to 2000 feet, for a distance of 2 miles. The average num- 
 ber of "payable" saddles in any one mine on the New Chum line 
 from the surface to 2000 feet, would be not far short of ten ; on 
 the Garden Gully the gold has been practically confined to two for- 
 mations. The Hustlers line had its greatest development in the 
 Great Extended Hustlers, the Hustlers, and the United Hustlers and 
 Redan. It has been worked less extensively than the other two main 
 lines of reef; but its known extent is great, and it should prove an 
 important producer in years to come. Of the various formations to 
 be seen in the mines of Sandhurst at the time of my inspection, the 
 largest, most extensive, and most profitable was that on the New 
 Chum lode between the New Chum railway and the "180" mine. 
 It extended through 14 different claims (see Fig. 7), a distance of 
 2400 yards, and was intercepted at depths which varied from 1600 
 to 2400 feet. I saw the development of this formation in six of the 
 mines through which it passed, and, with the aid of drawings repro- 
 duced from sketches made underground, I will endeavor to describe 
 the different modes of its occurrence. 
 
 THE NEW CHUM RAILWAY MINE. 
 
 The most southerly mine on this great body of gold-bearing 
 quartz is the New Chum Railway, which, on account of the good 
 returns obtained from this formation at 2025 feet depth, is often 
 quoted in the Colonies as an example of deep gold-mining. From 
 this company's ground the formation rises towards the Shenandoah, 
 where at 1990 feet* the west leg was being very profitably exploited 
 at the time of my visit. In the breast of the level and in the slopes 
 overhead, the reef is seen to be notably laminatedf and very well 
 defined. As the cap is approached the walls remain as before, but 
 the quartz becomes broken, dead-white in color, and with a splintery 
 
 * It will be seen that between the New Chum Railway and the Shenandoah, the 
 back or anticlinal axis of the formation pitches about 100 feet in 600. 
 
 f In Amador County, Cal., this would be called "ribbon-rock." In both Cali- 
 fornia and Australia such a structure is considered a favorable sign. 
 
THE BENDIGO GOLD-FIELD. 
 
 25 
 
26 THE BENDIGO GOLD-FIELD. 
 
 fracture at right angles to the walls. The cap or apex of the saddle 
 is poor, while the east leg soon gets small, and is never " payable." 
 Figs. 8,9, 10, and 11 illustrate the peculiarities of the formation. 
 A indicates sandstone, B slate, and C quartz. Fig. 8 shows the west 
 leg at the bottom level. The lode is about 7 feet wide, and consists 
 of beautifully laminated and mottled stone, carrying visible gold. 
 There is about 4 inches of selvage* or "dig" on the % hanging-wall, 
 shown at E. Fig. 9 shows the same lode at the north end of the 
 drift. It is here about 2 feet wide, closely laminated, but poor. 
 This is explained by the fact that going northward the level gets out 
 of the ore-shoot, which is rising overhead, pitching south. The 
 "spurs" or feedersf going off into the center-country are a common 
 feature in these mines. Fig. 10 illustrates the west leg a-few feet 
 below the turn-over of the saddle. The quartz, which is white and 
 barren, shows included fragments of country .-rock (D). Fig. 11 
 gives a general view in cross-section of the formation. The richest 
 ore was found along that part of the west leg which is marked by 
 crosses (to the right of N). The distance from M to N is 120 feet. 
 In the cross-cut, 60 feet below the cap of the saddle, the legs are 90 
 feet apart. Center-country consists of beds of hard sandstone, sepa- 
 rated by thin slate partings. A winze sunk below the cross-cut has 
 intercepted another small saddle, whose axis is a few feet eastward 
 from that of the main formation. 
 
 THE NEW CHUM CONSOLIDATED. 
 / 
 
 The next minej in which I studied this formation was the New 
 Chum Consolidated. Between this mine and the Sheuandoah the 
 formation undergoes a change. While it pitches south in the latter 
 (as we have seen), it turns over in an intermediate mine, Craven's 
 New Chum, and begins to take a northerly pitch, which character- 
 izes it in all the remaining mines through which we shall follow it. 
 It is scarcely necessary to add that in the exploitation of the mines 
 it is found that the back or anticlinal axis of the formation has not 
 
 * ''Dig" and "pug" are the names given in the Colonies to that which an 
 American calls "gouge," a Cornishman "hulk" and " fluccan," and which in the 
 text-books is termed "selvage." 
 
 f Irregular cross-veins of quartz, which are found traversing the country in all 
 directions, are called at Sandhurst "spurs" a good name, and almost equivalent 
 to the "feeders" and "droppers" of other districts. The short-lived, flat seams 
 are often called "floating spurs." 
 
 J See the plan, Fig. 7, of the mining properties referred to. 
 
THE BEXDIGO GOLD-FIELD. 
 
 27 
 
 . m^W'f!-- ' ,# 
 
 ^liiiPtev^ 
 ^iiSii'^:^!;!' 
 S^ill&ir-^ 
 
28 THE BENDIGO GOLD-FIELD. 
 
 that unswerving regularity which a general description might lead 
 one to infer, but is frequently broken by faults, and presents over- 
 lappings, which, however, do not prevent it from keeping a general 
 easily-recognized inclination. 
 
 In the New Chum Consolidated, the formation has undergone 
 several changes, as compared to its appearance in the Shenandoah, 
 and one would be led to believe that it consisted here of three sad- 
 dles, one above the other. If I read the facts correctly, there is 
 only one, which corresponds to that seen above the 1990 cross-cut 
 in the Shenandoah. At the mine, one is told that there is one con- 
 tinuous west leg, with three east legs ; but it seems to me th'at it 
 would be more correct to consider the lower two legs as " spurs " 
 from the west leg into the center- country, after the manner of the 
 veins shown in Fig. 9. By Fig. 12 it will be seen that the bend of 
 the saddle is very sharp, and that below the 1770-feet cross-cut there 
 is a break or fault. Center-country, as in the Shenandoah, is hard 
 sandstone, with traces of a westerly cleavage, while the bed overlying 
 the quartz is slate, which in the 1683-feet cross-cut, west of the cap, 
 shows a very strong cleavage of about 60 east. This has been 
 mistaken for bedding, so that one is told that the saddle is east of 
 center-country, and that the west leg cuts across the stratifications. 
 It is frequently the case that in the immediate vicinity of the saddles 
 the cleavage is so developed as to hide the bedding-planes. 
 
 The richest quartz, or (( best gold,"* was found on the west side 
 of the lower part of the cap, as indicated by crosses in my sketch. 
 The quartz of the stopes is generally very white and the gold com- 
 paratively fine. Near the lode there is a casing of black graphitic 
 slate, which is highly pyritiferous. In conclusion, it may be noted 
 that in this mine six saddle-formations have been discovered, from 
 the 1240 down to the 1810-feet level. 
 
 LANSELL'S " 222 " MINE. 
 
 Leaving this mine,f to which I hope to refer again as being one 
 of the best-equipped and best-managed properties on the field, 
 the next claim northward which I visited^ was Lansell's " 222," 
 
 * The Australian talks of '' fair gold," "good gold," " best gold," etc., meaning 
 that he is getting a fair amount, a good amount, etc., of.gold in the quartz; or, as 
 would be said out West, '* fairish rock," ' good dirt," the " best ore," etc. 
 
 f My best thanks are due to Mr. James Boland for his courtesy in guiding me 
 through the mine, etc. 
 
 J The New Chum United lies between the New Chum Cons, and Lansell's " 222." 
 
 $ The claim is about 222 yards long, while, similarly, the famous (l 180 " mine is 
 180 yards long. Both are the private property of Mr. George Lansell. 
 
30 THE BENDIGO GOLD-FIELD. 
 
 which communicates underground with the Lazarus mine, so that 
 it will be convenient to consider both together In these two 
 mines the overlying beds have been bent, with the result that the 
 arch of the saddle is broken, and a long neck of quartz marks the 
 fracture. At times, the formation looks like an ordinary junction of 
 two lod-es; and the highly developed cleavage would make it, re- 
 garded alone, difficult to unravel. At the 1900-feet level in the 
 " 222," the legs are only 20 feet apart, approaching each other 
 overhead so that both are worked in one run of stopes, the heading 
 of which presents the appearance of a big lode divided by a " horse " 
 of country. The quartz itself is from 5 to 20 feet wide, enlarging, 
 of course, near the cap of the saddle. Between the legs the country 
 is quartzose, and much broken up by a ramification of spurs which 
 with the cleavage obliterate the bedding. The cap forms a long and 
 narrow neck of ore, which extends for 81 feet above the level, break- 
 ing up "into spurs and irregular bodies of quartz at its upper end. 
 The formation at this level pitches north 1 in 10. 
 
 THE LAZARUS MINE. 
 
 In the Lazarus, the cap of the saddle, forming here also a narrow 
 neck of quartz, was followed down by the shaft from 1850 to 1960 
 feet, and proved " payable " most of the way. In the illustration 
 (Fig. 13) A is sandstone, which, near the saddle, is cut up by spurs 
 (as is usually the case where center-country is sandstone), but in the 
 2000-feet cross-cut is hard and clean. B is slate, the cleavage of which 
 is highly developed. The arrows (at E and W) indicate the bedding, 
 while the slanting lines mark the cleavage. E (at the top of the 
 Fig.) is at 1889, and D at 1960 feet below the surface. C is the 
 main body of ore, which is frequently disordered by minor faults, 
 such as x and y. That marked y, for instance, carries crushed quartz 
 3 to 4 inches wide, accompanied by softer materials (fluccan or sel- 
 vage). The spurs, indicated in A, show gold near the main lode. 
 Both legs and the cap have been profitably worked, the gold in the 
 legs being very coarse, more especially in the " west reef/ 7 where 
 pieces weighing from 1 to 3 ounces have been obtained. The quartz 
 itself is dead-white, with a splintery fracture, and when broken 
 rattles like fragments of porcelain. There is but little pyrites present, 
 and it is noteworthy that pyrites is generally absent from that part 
 of the lode which carries the coarsest gold. Below the formation 
 another saddle has been discovered, which may possibly be that which 
 was described as cut by the winze below the 1990-feet level in the 
 
THE -BEXDIGO GOLD-FIELD. 
 
 31 
 
 Shenandoah. In Fig. 11 this u make of stone " is shown. It is sep- 
 arated by 20 feet of sandstone from the main saddle; it is more 
 regular than the upper one, and its west leg carries " fair gold," 
 while the eastern is poor. 
 
 Only two paying formations have been intersected in this mine 
 in the last 1000 feet of sinking (that is, below the 1000-feet level), 
 namely, the saddle at the 1750, and that at the 2000-feet level above 
 described. In that portion of the mine below 850 feet, twelve for- 
 
 Fig. 34. 
 
 mations have been cut, most of which showed some gold ; but the 
 two above mentioned have been much the most productive. 
 The following list may be of interest: 
 
 Saddle cut at Remarks. 
 
 850 feet, /. . . . . " payable." 
 
 930 
 1040 
 1160 
 1240 
 1263 
 1435 
 1630 
 1750 
 1790 
 1837 
 
 - .. . / .-; -.,. * * . . no good. 
 
 . . . . .- . no good. 
 
 ... * no good. 
 
 7 dwts. first crushing, followed by a 4 dwt. yield. 
 
 . no good. 
 
 . no good. 
 
 . * . . . small, not payable. 
 
 * good. 
 
 poor. 
 
 broken, poor. 
 
 1889 to 2000 feet, very good. 
 
32 THE BENDIGO GOLD-FIELD. 
 
 THE NORTH OLD CHUM MINE. 
 
 Next to the Lazarus,* is the Old Chum, which I did not visit, 
 and then follows the New Chum and Victoria, which was not 
 deep enougnf to cut the formation which we have been following 
 through the different mines. Then follows the North Old Chum, 
 where, at 2290 feet, the main formation has been profitably devel- 
 oped. A cross-cut at that depth cut the west leg at 70 feet from the 
 shaft, and 45 feet further intercepted the east leg. A lava dyke 
 about 4 inches wide is seen 24 feet east of the west leg. The west 
 reef has been driven upon for about 20 feet each way. In the 
 north end it was 8 feet wide, with clean walls, carrying coarse J gold, 
 easily visible in the quartz which had the same dead-white color 
 and curious fracture as that of the Lazarus. There were to be seen 
 patches of mineral (mostly arsenical pyrites) arranged along the black 
 lines formed by some included slate. From this drift, during my 
 stay in Sandhurst, was broken stone which gave " the deepest divi- 
 dends" on record for the Southern hemisphere.! 
 
 In the south end the lode was smaller, as would be expected, since 
 the saddle pitches north. The width was 2 feet in the face, and the 
 back of the level showed coarse gold, the quartz being similar to that 
 of the north drift and accompanied by 2 inches of black clay or 
 "dig." The hanging-wall, as heretofore in the other mines, is seen 
 to be slate, while immediately under the foot-wall there is "cordu- 
 roy" or closely alternating thin beds of sandstone of varying hard- 
 ness and composition. Near the lode the country shows coarse 
 pyrites, arranged with no apparent regularity. 
 
 The east leg had not been driven upon when I saw it; but since 
 then it has been developed and has given good stone. 
 
 When the north drift from the 2290 -feet level in the North Old 
 Chum has been driven 300 feet further, it will connect with the 
 2300 feet level in Lansell's " 180" mine,|| the deepest in Australia. 
 
 * 1 take this opportunity to thank the mine-manager, Mr. T. Whitford, for his 
 courtesy in taking me through the workings. 
 
 f Since my visit the shaft has been sunk and the reef cut at 2260 feet. 
 
 I The coarse character of the gold is indicated by the yield of 223 oz. of gold 
 from only 341 oz. of amalgam. 
 
 For the week ending September 13, 1890, it yielded 223 oz. 9 dwts. from 141 
 tons, which result enabled a sixpenny dividend to be paid. The depth was 2290 
 feet. 
 
 || The opportunity is offered me in this connection to express my great obliga- 
 tions to Mr. George Lansell, the man who has done most to develop the Sandhurst 
 gold-field, for assistance given me in visiting the mines, as well as for valuable 
 information regarding mining and milling in the gold-field. 
 
THE BENDIGO GOLD-FIELD. 
 
 33 
 
 In this mine the crown or cap of the saddle is cut by the 2200-feet 
 cross-cut, 80 feet east from the shaft, showing a width of 12 feet of 
 quartz. At 43 feet a dike is cut. In the 2300-feet cross-cut the 
 west leg is cut at 58 feet, while the east leg is seen, broken up and 
 irregular, at 130 feet. The dike is cut at 56 feet. In the 2400- 
 feet cross-cut the west leg is 8 feet east of the shaft and the dike 46 
 feet. In the 2500-feet cross-cut this formation has not been cut, but 
 the west leg of another saddle is formed at 48 feet east, the corre- 
 sponding east leg being at 81 feet. The dike is at 58 feet. In the 
 2600-feet cross-cut the same dike occurs at 56 feet. The cross-sec- 
 tion (Fig. 14) illustrates these formations. The dikes, one of which 
 
 A Fig. 35. 
 
 A^MH n n,;')/O 
 
 SvvlMt^ 
 
 S^A^y ": 
 -^aiwv\\%-^T/:-: 
 
 PM>V^M 
 
 is shown in the section, are a most important and interesting feature 
 of the mining at Sandhurst, and will be referred to frequently. 
 
 THE a !80" MINE. 
 
 In the " 180" mine we see the furthest northern development of 
 the great saddle which we have followed through several mines and 
 which is first cut by the New Chum Railway. In the " 180 " mine 
 it has not been opened up much ; but at 2400 feet, in the south 
 level, it forms the deepest gold-bearing quartz now worked in the 
 colonies. The west leg, the only portion of the formation which is 
 worked at present, shows about 1 foot of very beautifully laminated 
 
 3 
 
31 THE BENDIGO GOLD-FIELD. 
 
 quartz. The quartz is brittle and flaky, the gold coarse and associ- 
 ated with a good percentage of iron pyrites and zinc-blende. On 
 the hanging- wall there is a black graphitic slate which carries a note- 
 worthy amount of mundic. The foot-wall shows cross-joints about 
 30 inches apart and nearly at right angles to the strike. The coun- 
 try is "corduroy," similar to that noted in the North Old Chum, 
 and carries pyrites near the reef. The cleavage is highly developed, 
 and to the east (about 60 feet) in the cross-cut, it obliterates the 
 bedding, though the latter is to be distinguished with difficulty to 
 the east near the east leg and to the west near the west leg. Be- 
 tween them the country is broken up and penetrated by the dike, 
 which has a slight easterly dip. 
 
 The illustrations represent other interesting features of the " 180 " 
 mine. Fig. 15 shows the point where the lava dike, about 8 inches 
 wide, strikes the top of the saddle above the 2500-feet level. The 
 arrows indicate the bedding; the slanting lines, the cleavage; E is 
 disordered country. The dike T appears to be cut off, but it finds 
 a passage in a plane other than that in which the section is taken. 
 A is broken sandy rock. O and C are fragments of the cap. Fig. 
 16 is taken in center-country at the 2500-feet level. The dike T 
 (here 10 inches wide) cuts through the spurs preparatory to taking 
 a more regular course conformable to the bedding. In Fig. 14, 
 already referred to, the dark line indicates the dike, which, though 
 it rarely exceeds 9 inches in width, has been traced through the 
 half-mile of workings from the surface down. It can be seen in the 
 2600-feet cross-cut and it is a noticeable feature of a surface cutting, 
 a sketch of which is reproduced in Fig. 12. Fig. 17 shows the dike 
 T where it forms a division in the quartz of the west leg (of the 
 2500-feet saddle) and carries included pieces of quartz, D. In this 
 figure B is slate, A is slaty sandstone, and C is quartz. Fig. 18 
 shows a fault, the throw of which is about 7 inches, as seen in the 
 2400-feet level. The sketch explains itself. 
 
 The underground workings of this very interesting mine* have un- 
 covered five saddles, of which the one at the 2400-feet level is the third 
 " payable" one. The other formations were cut at 560, 1560, 2000 
 and 2200 feet respectively. The east leg of the 2400-feet formation 
 is the longest east leg in the mine, 40 feet. The longest west leg 
 was worked from the 1600 to the 1870-feet level. The cap of the 
 
 * Mr James Northcote, the mine-manager, gave me a great deal of this informa- 
 tion and in many other ways assisted me in my examination of the gold-field. 
 

 THE BENDIGO GOLD-FIELD. 
 
 35 
 
 560-feet saddle was the most payable portion of that particular 
 formation. The east leg was short-lived, the quartz pinching, while 
 the wall or "back" continued. Generally speaking, the west legs 
 are the strongest and most auriferous in this, as in most of the 
 saddles of the New Chum line of reef. No considerable body of 
 gold-bearing stone has been worked below 1870 feet. 
 
 Barren quartz is rarely met with, but some is not of paying grade. 
 From 1560 to 1870 feet was worked the great saddle-reef of the 
 " 180" mine, there being a large body of stone or ore of extraordi- 
 nary richness on the west leg of the formation, which was first cnt 
 
 
 at 1560 feet. The deeper levels show no change in the character af 
 the country, and no large influx of water* hinders further sinking. 
 
 RECAPITULATION. 
 
 This concludes that portion of my notes which refers to the series 
 of mines in which is to be seen the main saddle formation of the 
 Sandhurst of to-day. It may be taken as typical of the great runs 
 of pay-quartz from which the field has obtained most of its gold. 
 During the time (the four weeks preceding October 13th, 1890) in 
 which I inspected the larger number of this group of mines, the re- 
 turns were as shown in the accompanying table. 
 
 The quantity of water hoisted is 3000 gals, per 24 hours. 
 
36 
 
 THE BENDIGO GOLD-FIELD. 
 
 -~ 
 
 MINE. 
 
 1st Fortnight, 
 ending Sept. 27, '90. 
 
 2d Fortnight, 
 ending Oct. 11, '90. 
 
 For the Month. 
 
 A 
 
 I 
 
 Loads. 
 
 Ozs. 
 
 Dwts. 
 
 Loads. 
 
 Ozs. 
 
 Dwts. 
 
 L'ads 
 
 Ozs. Dwts. 
 
 Feet. 
 
 2025 
 1990 
 1900 
 1400 
 1850 
 1850 
 1900 
 1960 
 1960 
 2290 
 
 New Chum Railway.... 
 
 527 
 385 
 209 
 108 
 736 
 416 
 
 474 
 479 
 95 
 45 
 532 
 117 
 
 1 
 3 
 10 
 5 
 12 
 11 
 
 512 
 365 
 145 
 160 
 757 
 420 
 
 643 
 379 
 100 
 56 
 378 
 72 
 
 1 
 1 
 4 
 14 
 2 
 8 
 
 1039 
 750 
 354 
 268 
 1493 
 836 
 98 
 441 
 505 
 460 
 
 1117 
 
 858 
 195 
 101 
 910 
 189 
 88 
 400 
 191 
 395 
 
 2 
 4 
 
 14 
 19 
 14 
 19 
 
 8 
 
 1 
 
 North Shenandoah 
 Young Chum 
 
 New Chum Con 
 
 New Chum United 
 Lansell's " 222" 
 
 Lazarus Co 
 
 231 
 256 
 181 
 
 163 
 52 
 743 
 
 17 
 
 7 
 11 
 
 210 
 249 
 279 
 
 336 
 138 
 241 
 
 11 
 13 
 10 
 
 Lazarus No 1 
 
 North Old Chum 
 
 Ten mines are included in this list, there being no crushing from 
 the " 180 " mine for this particular period. The returns for the 
 separate fortnights are given so as to show how far the yields vary. 
 Nine out of the ten are dividend-paying properties at the present 
 time, and the figures show that the average yield is 444 oz. 16 dwt. 
 from an average output for the month of 624J loads,* these results 
 being obtained from workings whose depth is 1912J feet from the 
 surface. This is a good record for deep quartz-mining. 
 
 OTHER UNDERGROUND PHENOMENA. 
 
 Before proceeding to describe the underground phenomena ob- 
 served in others of the mines it will be well to refer again to the gen- 
 eral structural geelogy of the district. Emmonsf quotes a saying 
 of the geologist Von Groddeck that the understanding of the true 
 character of veins can only be arrived at by study of the structure 
 of the region in which they occur. Of no mining district can this 
 be said more forcibly than of Sandhurst. As we have already seen, 
 the gold-field is situated among the highly contorted folds of the 
 Lower Silurian slates and standstones. The fissuring which is the 
 accompaniment and result of extreme contortion has led to the pro- 
 duction of very diverse forms of ore-deposition. We have seen 
 something of the saddles and synclines (troughs or inverted saddles). 
 
 * A load is equal to 25 cwt. (avoirdupois, at 112 pounds) of ordinary ore, or 30 
 to 35 cwt. of concentrates. 
 
 f " The Structural Kelations of Ore-deposits," Trans., xvi., 804. 
 
38 THE BENDIGO GOLD-FIELD. 
 
 For reasons to be discussed in the sequel, the latter are neither so 
 extensive nor so productive as the saddles proper. In addition to 
 these two very beautiful types of ore-deposition, there are in the 
 Sandhurst mines good examples of almost all the best recognized 
 forms in which gold-quartz is known to occur. When the parting 
 between two adjacent beds has been a line of movement, the distinct 
 division as produced in the country is recognized and named a 
 " back. 7 ' It is usually accompanied by a smooth wall forming the 
 surface of the harder ,of the two beds, and by more or less black 
 selvage or gouge, resulting from the abrasion to which one of 
 the two beds has been subjected. Such a " back " offers facilities for 
 the deposition of quartz by the waters to which it gives a ready 
 passage. A " back " accompanied by quartz, whether a mere thread 
 or several inches in width, becomes a "leader," the word referring 
 more particularly to the quartz seam which serves as a guide in 
 prospecting the ground. Such a deposit would come under the 
 category of " bed- veins." 
 
 Another very common, often also very extensive and profitable, 
 formation is locally known as a " make of spurs" It consists of a 
 network of quartz-veins, traversing a more or less definitely limited 
 section of country. They frequently start in the neighborhood of a 
 " back " or " saddle," and intersect the slate and sandstone at a 
 strong angle with their bedding. These spurs are sometimes so 
 numerous as to make the country almost entirely quartzose, while in 
 other instances, though continuous and following a distinct belt of 
 country, they may be so far apart as to hide their true character. 
 In various forms these spur-systems constitute one of the -most im- 
 portant sources of the gold obtained in the Bendigo* mines. When 
 they accompany one of the main reefs they may be considered as 
 " feeders ;" when they form a distinct reticulation of quartz- veins they 
 answer to the term of " stockwork." 
 
 Midway between the forms known as " backs" and " makes of 
 spurs " come the " lodes." These consist of occasional belts of country- 
 rock, most frequently slate, which carry irregular seams of quartz, 
 some of which are arranged parallel to the walls (the bedding planes 
 of the country), while others have a transverse direction. Such oc- 
 currences are locally called by the generic term of " lode," differing 
 from a " make of spurs " in that the quartz-seams are confined to one 
 
 * The best-producing mine at the present time the New Red, White, and Blue 
 Consolidated is developing one of these " makes of spurs." 
 
THE BEXDIGO GOLD-FIELD. 
 
 39 
 
 bed alone, and from the backs and leaders in being larger and less 
 defined, and in carrying a greater proportion of country-rock. 
 
 Fissures containing quartz and traversing the country unconform- 
 ably to the bedding, are often faults and would answer to the " true 
 fissure-vein,"* a type which is of frequent occurrence in this field, 
 though not so important a repository of the precious metal as the 
 saddles or spurs. " Bulges," " blocks," etc., are names given to 
 irregular bodies of quartz, presenting features more or less in common 
 with the preceding types. At Sandhurst, as elsewhere, the different 
 forms of ore-deposition cannot be arbitrarily labelled, exhibiting as 
 they do frequent gradations from the one to the other. In the para- 
 Fig. 38. 
 
 graphs which follow, I will describe instances of the type known as 
 "saddles," leaving the other forms for subsequent consideration. 
 
 THE SOUTH NEW CHUM MINE. 
 
 At the southern end of the district about 3J miles from the 
 group of big mines on Victoria Hill, some of which have been passed 
 in review there is a small mine called the South New Chum, which 
 
 * This form of ore-deposit was at one time erroneously considered as particularly 
 favorable to the occurrence of continuous shoots of gold-bearing stone. 
 
40 THE BENDIGO GOLD-FIELD. 
 
 admirably illustrates the particular formation most characteristic of 
 Sandhurst.* 
 
 This n^ine is working in regular "saddle-country." The longi- 
 tudinal and cross-sections given in Figs. 19 and 20 will serve to 
 explain it. The underground developments of this mine and its 
 northern neighbor, have proved the existence of three formations, 
 all pitching strongly to the south. 
 
 Formation No. 1 came to' the surface 120 feet from the South New 
 New Chum shaft. The line drawn in the section, Fig. 19, is the 
 anticlinal axis of the saddle. Looking along the strike, it would 
 appear like the ridge of a roof, sloping rapidly southward. At A 
 the cap of this formation was strongly defined and very rich in gold. 
 Near the surface both legs proved " payably " auriferous. At B, 
 the saddle was not " payable." At C the cap became gold-bearing, 
 and was well denned as it approached the next shaft to the south. 
 
 Formation No. 2 is the one which is shown in the cross-section, 
 Fig. 20, which is taken in a plane 5 feet south of the line of the 
 shaft. Both the 170- and the 2SO-feet cross-cuts passed through it. 
 At D, Fig. 19, the cap is broken, and there was no quartz in the 
 legs. At A the cap became " payably " gold-bearing as it ap- 
 proached the line of the shaft. The east leg was not worked, and 
 the west leg was also poor. At B there was a " payable " cap and 
 west leg, between the 170- and 280-feet levels. At C, the formation 
 is irregular and broken. 
 
 Formation No. 3 is cut through by the shaft and is again partially 
 exposed at the 550-feet level. The cap is irregular. The west leg 
 is worked, but the east leg has not yet been reached by the cross-cut. 
 Referring to the cross-section* Fig. 20, I will transcribe the notes 
 made by me while underground. 
 
 At the 170-feet level. East leg cut 10 feet east of shaft. The lower dyke* 12 feet 
 and west leg 34 feet, both west of shaft. The lower portion of the cap is passed 
 through in sinking at 125 fee , the top of the cap being 5 feet west of the shaft. 
 The lava dike is 4 feet wide, divided by 2 to 3 inches of slate, which, through- 
 out the upper workings, separates it into nearly equal portions. The cleav- 
 age of the country is with the east leg, slightly over the cap and stronger a short 
 distance above. On the other side of the saddle the cleavage is decidedly across 
 the west leg. The formation pitches strongly southward, 1 foot in 6, and at 
 times even 1 in 5. 
 
 * I owe thanks to Mr. L. A. Samuels, the mine manager, who conducted me 
 through the workings during my visits at the mine and gave much interesting 
 information. 
 
THE BEXDIGO GOLD-FIELD. 
 
 41 
 
 At the 280/eef level. East leg 74 feet east of shaft. Lava dike in the plat.* 
 West leg 84 feet west of shaft. The dike is increased in size, the two portions 
 being divided by two feet of slate. The cross-cut shows a subordinate saddle un- 
 derneath the main formation. This secondary saddle carries a little quartz (4 to 
 5 inches), which in the shaft showed "nice gold." The west leg (of the main 
 saddle) consists of two parts, each about 5 inches in width, the quartz of which is 
 very beautifully laminated or ribboned. The hanging-wall is clean and defined, 
 inclining at a less angle than in the level above. The cleavage west of the center- 
 country is slightly west, nearly upright, and cuts across the bedding, which is 
 readily recognizable. The country east of the west leg is slate (2 feet thick) over- 
 lying sandstone, the thin bedding of the latter being very marked. The east leg 
 as cut in the cross-cut is small and poor, but is overlain by country corresponding 
 to that which covers the west leg. 
 
 Fig. 39. 
 
 At the 45Q-feet level. The legs of the upper formation have not been sought for, 
 as they both became small and poor below the 280-feet level. The east leg; would 
 be about 150 and the west leg 200 feet from the shaft. At 35 feet east of the shaft 
 a western "-back" is struck, this proving to be the continuation of a wall coming 
 from a saddle below the level. The lava is cut at 36 feet from the plat ; it here 
 shows only a fine black line dividing the two portions. . 
 
 At the ooQ-feet level. In the plat the sandstone of the west country shows ripple 
 markings. The west leg of the third formation is cut close to the shaft, and has 
 been driven upon for 118 feet southward. 
 
 The east leg has not yet been cut, though the cross-cut has been put out in 
 
 * The station at the shaft, often called the " station." Literally, " plat " means 
 a flat place cut out. The Cornish talk of a *' tip plat," the flat place where the ore 
 is accumulated, with facilities for discharge below the level. 
 
42 THE BENDIGO GOLD-FIELD. 
 
 that direction for 69 feet. It is estimated that 20 feet more would find it. The 
 cross-cut very clearly shows the bedding of the country which is pierced by the 
 lava dikes, which here are 16 feet apart. The south drift is on the west leg. 
 While the wall (the " west back " of the 450-foot cross-cut) continues its course, 
 accompanied by a seam of quartz ("the leader"), the west ''reef" turns off east- 
 ward and strikes against the lava dikes, but has not yet been crossed by them. 
 The quartz which here is highly auriferous is found to occur both between the two 
 dikes and west of them. The end of the drift is in lava. 
 
 Figs. 21 to 27 inclusive illustrate some of the more interesting of 
 the underground features already referred to. Fig. 21 shows the 
 second formation as disclosed in the workings above the 170-feet 
 level. There is no doubt as to the continuity of the beds forming 
 this anticline. Sandstone A overlies the saddle, of which B and D 
 are respectively west and east legs. C is the body of quartz form- 
 ing the apex; above it there is a wedge-shaped mass of crushed 
 country, consisting for the greater part of black broken slate con- 
 taining a notable percentage of pyrites, but no u payable " amount of 
 gold. The slate underneath the west leg varies from 2 to 3 feet in 
 thickness, and is divided by a thin "bar" (3 to 4 inches) of hard 
 sandstone. Underneath the east leg there is also from 2 to 2| feet 
 of slate, while below the cap this slate is irregular and forms 
 " bulges/' This bed overlies the hard sandstone H of the center- 
 country, fractured and penetrated by spurs. The east back F, that 
 is, the parting which forms the hanging-wall of the east leg, has been 
 followed for 30 feet above the cap of the saddle. 
 
 Fig. 22 is the west leg, as seen at the 550-foot plat. The reef C 
 is hard against the back A, which carries its own thin vein of quartz 
 (the leader). D D are spurs from the west leg into center- country. 
 These cross-spurs are a frequent feature of the country between the 
 legs of a saddle. 
 
 Fig. 23 represents in plan the position of the " lava streaks" in 
 the south drift of the 550-feet level. S and T represent the dikes ; 
 C is the quartz ; and A, A the " back." 
 
 Fig. 24 shows the relative position of the dikes, as disclosed in 
 the 550-foot east cross-cut-. The bedding of the country is very evi- 
 dent. T, which is from 18 to 20 inches thick, is just east of center- 
 country, and has cut through it. S is 20 inches thick, and has just 
 begun to shape its course with the bedding. 
 
 Fig. 25 represents the markings, natural size, in the decomposing 
 lava of the west dyke in the 550 cross-cut. 
 
 Fig. 26 shows the " west back," which, 40 feet above the 550-ft. 
 level, runs into the west leg of an incomplete saddle (the third form- 
 
THE BEXDIGO GOLD-FIELD. 
 
 43 
 
 ation). It will be understood that a " back " is such only so long 
 as it follows the line of parting between two beds of the country ; 
 that when it follows a quartz seam it often becomes the hanging- 
 wall of a reef; and finally that, before striking the quartz or 
 after doing so, it may change its character and be a cross-fissure. 
 In Fig 26, A is the back ; C is quartz; S and Tare the two portions 
 of the lava dike which cuts through the formation. There is a 
 fault, the throw of which is from 8 to 10 inches. The dike does 
 not fault the quartz, but follows the line of an earlier dislocation. 
 D is broken ground, traversed by spurs. B is an east back. 
 
 Fig. 27 is taken from the cross-cut at 190 feet, and indicates a 
 local fault which throws the country about 3 feet east. B, B is a 
 
 bed of slate; F, F is the line of fault, carry ing a couple of inches 
 of selvage and, on the under side, a little quartz. 
 
 This mine illustrates the general character of the sad die-reefs. To 
 any one desirous of obtaining the key to the geological structure of 
 the district I recommend the examination of formation No. 2 as cut 
 by the 170 and 280- ft. cross-cuts, where the different features of 
 cleavage and bedding of the enclosing country, the pitch and under- 
 lay of the quartz bodies, are all more distinctly marked than I ob- 
 served them in any other mine. On the other hand the lower or 
 No. 3 formation, as cut by the 450- and 550-ft. cross-cuts well illus- 
 trates the frequency with which the simpler type of ore-deposits 
 becomes complicated almost beyond recognition. That this is due to 
 
44 THE BENDIGO GOLD-FIELD. 
 
 the action of faults, is evidenced by the slickensides on the walls 
 and the crushed condition of portions of the country, such as the 
 wedge of slate above the No. 2 saddle. 
 
 In this mine there is none of the perplexity occasioned in the deep 
 mines on Victoria Hill by the difficulty in distinguishing the bed- 
 ding from the cleavage, where the latter is highly developed. The 
 cleavage which elsewhere so often obliterates the bedding, especially 
 of the west country, is clearly distinguishable in the slate and sand- 
 stone beds disclosed by the different cross-cuts. 
 
 The 280-ft. level, where it is driven upon the western leg particu- 
 larly, well illustrates this feature. The sandstone there seen over- 
 lying the reef is composed of a number of thin beds of different 
 shades of gray rock, the light and dark laminae are beautifully regu- 
 lar, and have a strong dip westward (with the reef), while the 
 cleavage is only slightly off the vertical, giving the foot-wall in the 
 "drive" the appearance of taking a roll. The side of the level 
 had broken first along the wall of the reef which is also the bedding 
 of the enclosed country and then along the nearly vertical cleavage. 
 
 In conclusion I may add that though the mine is called the South 
 New Chum, having been originally supposed to be a southern con- 
 tinuation of that great " line of reef," it is now generally accepted 
 as being on an extension of one of the "side-lines" to the west. 
 
 THE JOHNSON'S MINE. 
 
 The finest example of the saddle-reef to be seen at the present 
 time is in the Johnson's mine at Eaglehawk. This claim is not, like 
 most of those hitherto described, on the New Chum line of reef, but 
 on the northern extension of the Garden Gull^ so called after the 
 mine in which it had its greatest and richest development, the Garden 
 Gully United. There has been but one saddle worked in the Johnson's 
 mine, but that one has been exceptionally regular and rich. The 
 apex is 980 feet from the surface ; the west leg has been but little 
 developed as yet, but the east leg still continues profitable beyond 
 the 1340-ft. level, which is the deepest in the mine. 
 
 All the gold obtained in the workings came from " backs " and 
 " spurs," as well as other irregular bodies of stone or quartz.* De- 
 scending No. 2 shaft a thousand feet, one finds that the level is 
 driven upon " the main east back," as it is called. It may be con- 
 sidered as an east leg which has no corresponding west leg; nor, so 
 
 * The Colonial talks of " stone," where the American speaks of " rock," and the 
 Frenchman " mineral." Gold-quartz in Australia is " golden stone." 
 
THE BE^DIGO GOLD-FIELD. 
 
 45 
 
 far as it has been followed, does it turn over to form a saddle. This 
 " back " has been worked successfully for 300 feet along its strike, 
 the quartz making in bulges, sometimes 100 feet in height, but of 
 very variable longitudinal extent. The gold-contents varied from 
 3 to 10 dwt. per ton. These bodies of quartz pitch north. Before 
 coming to an end they usually break up into a number of spurs, 
 and they are generally to be found at those points where a number 
 of small veins feeders or spurs -join the main back. Such a 
 " make of stone " * is to be seen above this 1000-ft. level. The 
 
 Fig. 41. 
 
 
 fcL^J 
 
 1 i ^ O --Or X-- ;: -'- v 
 
 quartz, 12 feet wide, is crystalline and white, but well mineralized, 
 containing vugs or geodes and occasionally patches of included 
 country. This block of quartz pitches north, but 60 feet further is 
 another which pitches in the contrary direction. A small regular 
 seam usually accompanies the back. It is known as the u leader, 
 and is distinct from the other irregular bodies of quartz which may 
 be found along the line of the back. The terms " back " and 
 " leader " are used interchangeably. The wall of the back is very 
 well defined, and carries a couple of inches of black clay the 
 " dig " which continues long after the quartz has died out. Figs. 
 28 and 29 will illustrate this. A is sandstone ; C is massive quartz ; 
 B is slate ; L is the leader ; D is the dig or selvage ; F, F are small 
 spurs. A cross-cut 85 feet east from this back brings us to the east 
 
 * A " make of stone" is the equivalent of a "shoat of ore" or an "ore-body." 
 
46 THE BENDIGO GOLD-FIELD. 
 
 leg of the big saddle. The cross-cut shows that on the hanging-wall 
 there are 14 feet of sandstone, divided by three thin partings of 
 slate. Both walls are very clean and distinct, the hanging par- 
 ticularly. 
 
 Above the stopes the saddle itself is seen. The appearance of 
 the workings is very striking. The removal of the quartz has left 
 a large vaulted chamber, over which the curving hanging- wall ex- 
 tends with the regu[arity of an arch of masonry, while the foot-wall 
 underneath looks like the back of a boiler, the curve of the saddle 
 being remarkably regular. As there is no timbering to obstruct the 
 vein, it is easy to sketch the heading. Fig. 30 shows the general 
 structure of the formation. Looking along the crest the summit 
 of the curving under-wall one can readily see that the piteh is to 
 the north. The overlying rock is the hard sandstone which forms 
 the hanging-wall ; underneath comes 2J feet of quartz ; then follows 
 a dark parting of slate, under which lies 12 to 14 inches of sand- 
 stone, then 5 to 6 inches of slate, mixed up with quartz, which latter 
 gets rapidly smaller both east and west. 
 
 These layers of slate, sandstone and quartz are all conformable to 
 the bedding of the enclosing country. The over- arch ing wall of 
 sandstone shows wavy markings, a suggestion of the beautiful rip- 
 ple-markings to be seen at the 1060-ft. level. There are also to be 
 observed thin threads of quartz, in lines at right angles to the 
 strike probably following joint-planes. 
 
 The west leg has been followed only 30 feet on the dip. Fig. 31 
 illustrates its appearance. Under the hanging is 12 to 14 inches o'f 
 clean quartz, C, well laminated. Underneath comes 2 feet of sand- 
 stone, A, separated by a black slate parting. Between this sand- 
 stone and the main foot-wall there is 5 inches of slate, B. The 
 hanging is broken by feeders which carry gold. The cleavage of 
 the country-rock is to the east, as indicated ou the right of the 
 drawing. 
 
 The east leg has supplied the major portion of the output of the 
 mine, and has proved highly auriferous. Fig. 34 shows its appear- 
 ance just below the cap of the saddle. The reef at this point is 
 divided into two parts by about 12 inches of sandstone, H. The 
 upper portion, C, is 2J feet wide, mottled by the inclusion of bits of 
 country, M, near the hanging-wall, and well laminated or ribboned 
 (N) near the included sandstone, H, which last is cut up by spurs, 
 
 s, s. 
 
 The underlying slate, B, is black and graphitic. The lower por- 
 
THE BENDIGO GOLD-FIELD. 47 
 
 tion, E, of the reef is less regular, and lies directly upon the hard 
 sandstone, D, of the main foot-wall. At about 40 feet below the 
 cap the east leg, as seen in Fig. 32, pinches to 3 inches at C, with 4 
 feet of slate, B, and sandstone, A, between it and the hanging. The 
 decrease in size is compensated for economically by an increase in 
 the gold-contents. 
 
 At the 1065-foot level the lode has been worked out. At the 
 1280-foot level a cross course throws the east leg, which is here from 
 9 to 10 inches wide, eastward 6 feet, which is equivalent to its being 
 moved from one wall to the other of the lode-channel in which it is 
 situated. This is shown in Fig. 33. At this point a body of quartz, 
 C, about 6 feet by 6 feet, is formed. It is very white, and has been 
 
 Fig. 42. 
 
 Fig. 43 
 
 known to carry coarse gold. A is sandstone; B, slate ; R, the reef. 
 The north end of the 1280-foot drive shows two faults* in the lode. 
 See Fig. 35. The larger has a throw of 8 inches. Both dip west- 
 ward, but at different angles. The quartz, A, on the foot- wall side, 
 is much the best in appearance and in yield. The foot-wall itself is 
 well defined and unbroken. B is broken, slaty rock, containing 
 pieces of quartz. C is a body of quartz, white, and containing but 
 little gold. 
 
 In the stopes the same faults are found closer together. The spurs 
 
 * In the mine they call them "slides." Elsewhere in Australia this term alter- 
 nates with "heads" and <% breaks." In the Xew Zealand coal-mines the synonym 
 is " troubles." 
 
48 THE BENDIGO GOLD-FIELD. 
 
 in the foot-wall going west from the reef pay to follow for 20 or 25 
 feet. The quartz of which they are formed is white and the gold is 
 coarse, not varying in this regard whether near or distant from the 
 main lode. The tenor of the ore is such that the reef will pay to 
 work when only 3 inches thick, the miners breaking with it feeders, 
 spurs, mullock,* everything as it comes. The average width, 
 however, is from 12 to 16 inches, at which size the lode is most 
 gold-bearing, better than when it increases to its maximum width 
 of 3 feet. 
 
 At the 1340-feet level the east leg is still rich in gold. It is be- 
 coming more inclined, having travelled east 10 feet in the last 60, 
 while between the 1000- and 1280-feet levels it moved 90 feet. 
 There is not so much country-rock between the walls as in the levels 
 above. The quartz is covered by a very clean striated hanging- wall, 
 which is 4J feet west of the main hanging of the lode-channel. In 
 the breast of the north drift the reef is 6 feet wide. The foot-wall 
 is a sandstone so far altered and hardened as to be a quartzite. Rip- 
 ple-marks are beautifully distinct. There is a fine line of stopes 
 above this level. Faults similar to those in the 1280 are seen. The 
 broken country under the faults shows evidence of having been 
 arranged in lines parallel to the lode. In the south drift is seen the 
 lava dike, shown in Fig. 36. B is a fault, the course of whjph is 
 marked by soft broken slate. The reef, A, is twice dislocated, the 
 second time by a small fault, which has served as a passage-way for 
 the dike, T. 
 
 This 1340-feet level is at present the deepest in the mine. The 
 reef has been followed by a winze for a further depth of 35 feet. 
 The shaft is now being sunk so as to enable deeper levels to be 
 opened, and so continue the development of the mine. A cross-cut 
 is being driven to intercept the west leg. 
 
 The richest ore which this formation yielded was obtained just 
 below the turn-over of the saddle, but very rich shoots were found 
 irregularly distributed through the reef, having the same pitch as 
 the formation itself. The quartz, speaking generally, is patchy, and 
 sometimes extremely rich bunches are found. One of these lately 
 gave 150 ounces of gold from a half-sack of quartz. 
 
 * Mullock is waste rock. A "mullock-tip" is brother to the western " dump." 
 Originally, mullock was the name given to the basalt which covered the deep leads 
 of Ballarat; but since then the alluvial diggers have introduced the term into 
 quartz-mining ; and at Sandhurst it refers to the slate and sandstone which is broken 
 with the quartz of the reef. 
 
THE BEXDIGO GOLD-FIELD. 
 
 49 
 
 As we have seen, most of the workings are on the east leg, which, 
 as observed in the levels underneath the cap of the saddles, presents 
 all the appearance of an ordinary quartz-lode with walls parallel to 
 the bedding of the enclosing country. The cross-cuts show the bed- 
 ding. The alternating slate and sandstone are called "bars" by 
 the miners. Thus, one hears of a cross-cut having just passed 
 through a " tight bar of sandstone." Even where the difference in 
 the nature of the rock forming adjacent beds is very slight, there are 
 lines of parting (usually seams of slate) which indicate the stratifi- 
 
 cation. The cleavage is distinct and uniformly to the east at an 
 angle of 60. 
 
 The Johnson's mine for the half-year ending June 30, 1890, paid 
 dividends amounting to 19,441 2s. The yield of 12,367 loads of 
 stone was 9146 oz. 3 dwt, worth 38,639 5s. 3d., and averaging 14 
 dwt. 19 gr. per load. The following figures will be of value as in- 
 dicating the tenor of the ore at the different levels during the half- 
 year : 
 
 Part of the Mine. 
 
 Above the 550-feet level, . l . 
 1000-feet level, 
 1130-feet level, 
 1200- and 1210-feet levels, 
 12SO-feet level, 
 1340-fei-t level, 
 
 4 
 
 Loads. 
 
 Yield. 
 
 (About 2800 Ibs: each.) 
 
 Oz. dwts. 
 
 . 121 
 
 13 10 
 
 . 1886 
 
 991 3 
 
 . 289 
 
 206 16 
 
 s, . 2156 
 
 1274 17 
 
 . 5145 
 
 3276 17 
 
 . 2113 
 
 2803 19 
 
50 THE BENDIGO GOLD-FIELD. 
 
 The average yield from the stone at the bottom of the mine was 1 
 oz. 7 dwt. per load.* 
 
 The Johnson's mine is on the Garden Gully line of reef, but 
 the next to be described is on the third of the three great anti- 
 clinal axes the Hustlers. The Great Extended Hustlers is one of 
 the " record-mines" of the district,f and at the present time exhibits 
 a formation of subsidiary saddles which is both peculiar and inter- 
 esting. Fig. 37 illustrates the formation as it is seen in the workings 
 between the 1700- and 1800-feet levels. The cross-section is taken 
 along a 6, and, with the longitudinal section, will explain itself. A 
 is slate, B and C are both sandstone. It is seen that the anticlinal 
 axes (the ridges of the saddles) pitch strongly to the north, the main 
 axis 1 in 5, while the secondary saddles pitch 1 in 3. The main 
 formation has been worked for 800 feet in this mine, and extends for 
 some distance into the adjoining claims. The secondary saddlesj have 
 a length along their strike of 250 and 300 feet respectively. 
 
 In Fig. 37 it is seen that, commencing at the south, the right hand 
 of the drawing, a cross-section would show one large saddle; as we 
 proceed north the great width of quartz becomes divided by a horse 
 of sandstone which, like a wedge, eventually splits the formation 
 into two saddles, having at a-b a width through their caps of 40 
 and 12 feet respectively. At this point the top of the main cap 
 is irregular, broken into a mass of spurs. The foot-wall of the lower 
 saddle forms a very clean arch. Further north again, the lower 
 saddle gradually pinches out, while simultaneously the main forma- 
 tion increases in size, very soon to be again divided by another wedge 
 of country-rock, with repetition of the conditions already noted in the 
 previous case. 
 
 Before the two saddles become divided by the country-sandstone, 
 
 * My thanks are due to Mr. Williams, the mine-manager, as also to the under- 
 ground foreman, for the details here given. 
 
 f It is a noteworthy fact that the three mines which perhaps rank first in the 
 returns of gold which they have made, should be on the three main "lines of reef," 
 and opposite each other, illustrating the old mining aphorism, "ore against ore." 
 I refer to the " 180 " on the New Chum, the Garden Gully on the line of the same 
 name, and the great Extended Hustlers on the Hustlers line. 
 
 % During my later visit to Sandhurst the manager informed me that he had come 
 across a third of these subsidiary saddles. I had not the time to inspect it. I have 
 here an opportunity of thanking the mine-manager, Mr. Thomas Heckley, for the 
 valuable assistance he gave me in visiting this mine, as well as for his guidance in 
 examining the old working* of the Unity mine. 
 
THE BENDIGO GOLD-FIELD. 
 Fig. 45 
 
 51 
 
 188 FT. CROSSCUT- 
 
 894 FT. CROSSCUT- 
 
 UNITY MINE. 
 
 53 FT. CROSSCUT. 
 
 SCALE. 1 = 40'' 
 
 E3QUART2 _LAVA DYKES 
 
 ^2S38AMD8TONE [T^) SLATE 
 
 atM. 
 
52 THE BENDIGO GOLD-FIELD. 
 
 the main body of the quartz begins to show included fragments of 
 country ; becomes, as the Sandhurst miners say, " mullocky."* 
 
 At the 1750-feet level, the east leg carries three or four inches of 
 quartz against a sandstone wall which exhibits transverse markings. 
 These will be referred to later. The quartz is crushed so as to re- 
 semble common table-salt, and occasionally the surface where it has 
 not been pulverized shows beautiful slickensides, polished to the 
 likeness of ivory, and veined with black streaks due to the grinding 
 of the pyrites. The west leg shows a large body (5 to 6 feet) of 
 white and splintery quartz. 
 
 The saddle was most auriferous at and immediately below the 
 commencement of the legs. This was particularly marked in the 
 case of the west leg, which was by far the more auriferous of the 
 two. In another formation, worked in the levels immediately over- 
 head, the reverse was the case ; the east leg paid best, often proving 
 continuously gold-bearing for from 150 to 200 feet; whereas the 
 east legs are generally short-lived. 
 
 The sandstone overlying the saddle is 10 to 15 feet in thickness, 
 and is overlain by a bed of slate 25 feet thick over the cap, and 
 penetrated lower down by the 1800-feet cross-cut, the slate being 
 thinner on the west side than on the east, where it is much disturbed 
 arid broken. 
 
 The sandstone over the cap has a nearly vertical cleavage ; that 
 of the west country is strongly east, while that of the eastern country 
 .is slightly westward ; in other words, the cleavage is radiated. This 
 is illustrated in Fig. 38. 
 
 In Fig. 39, one of the lower secondary saddles is shown. The 
 cleavage over the cap is also radiated and distinct, though it does 
 not entirely hide the bedding. Above the cap, at B, and in the 
 quartz itself, at C, there are a few inches of black slate. In the 
 center-country underneath, there is the suggestion of a third saddle, 
 D, in the quartz seam following the slate-parting which marks the 
 bedding of the sandstone. 
 
 Fig. 40 is taken in the 1805-feet level. A B is a bedding-plane, 
 sandstone above and slate underneath. The lines C, C, are joint- 
 fractures ; S, S, are small spurs cutting across both divisions in the 
 country-rock. Underneath the second saddle in the same level are 
 seen the fractures shown in Fig. 41 ; A B is the east leg, C is a 
 quartz seam following the bedding ; a a are lines of normal cleavage. 
 
 * That is, mixed with mullock or country-rock. 
 
- . 
 
54 THE BENDIGO GOLD-FIELD. 
 
 The system of fractures to which b b belong appears to me to be also 
 cleavage, but due to the transverse (north and south) folding of the 
 country. In other words, there is here double cleavage, one due to 
 the east and west, and the other to the north and south, bending of 
 the beds. The planes b b are at right angles to the plane of A B 
 (the bedding) and are not confined to the bed only. 
 
 Reference has been made to some peculiar markings seen above 
 the east leg of the main formations. They are more plainly seen in 
 the sandstone above the west leg at and about the turn-over of the 
 saddle. As seen underground, they present the appearance shown 
 in Fig. 42. The deepening and thinning of the dark lines is due 
 to the unevenness of the surface produced in breaking it. Actually, 
 the lines are as shown in Fig. 43. They are identical with the 
 cleavage, and present an instance of cleavage which is also crystalline 
 lamination, that is, they are lines due to compressive strain, along 
 which a dark indeterminate mineral has been developed and arranged. 
 
 Fig. 44 is a " false saddle" seen in the 1670-feet level. B is slate, 
 the cleavage of which is indicated, as is also that of A, which is a 
 slaty sandstone. T is a lava dike, 12 to 14 inches wide. D is a 
 slaty sandstone, broken up and containing irregular fragments of 
 quartz at E, E. The bedding, to the west, is indicated by the arrow. 
 This is a typical instance of a quartz formation which is very apt to 
 be mistaken for a true saddle.* Quartz is formed along the fissure 
 which cuts across the bedding of the country, the bedding-planes 
 themselves also show quartz, and the point of intersection with the 
 fissure may be marked by a large body of ore. In this case the 
 dike follows the line of the cross-fissure and a formation of quartz 
 (C) is seen. It is to be noted that the line of bedding is more favored 
 in the deposition of quartz than that of the fissure which crosses it. 
 Such " makes of stone " are notably irregular and uncertain. At 
 the point where the sketch is taken the lava is just west of "center- 
 country/ 1 and the reef underneath the lava is of very limited extent. 
 In going south, the dike makes over to the east country, the country 
 dipping east, and the accompanying quartz then becomes more contin- 
 uous. 
 
 THE UNITY MINE. 
 
 At the Unity mine, which is on the Garden Gully line, there is a 
 good example of the extensive faulting which frequently obtains in 
 this district, making difficult the development of the ore-bodies. 
 
 * As already noted in the beginning of this paper. 
 
THE BENDIGO GOLD-FIELD. 
 
 55 
 
 Fig. 45 is a section, 40 feet to the inch, which will serve to explain 
 the occurrence. B A C is an imperfect but true saddle, since the 
 country dips east and west with the two legs. There is no true east 
 leg, but rudiments of it are seen in the spurs which traverse the 
 slate at S. Sandstone overlies the cap and the west leg, as well as 
 the bed of slate in which are the spurs which replace the east leg. 
 At 28 feet below the cap, the country is faulted, the throw bringing 
 the west leg, the only part of the formation which continues well- 
 
 Fig. 52. 
 
 VICTORY AND PANDORA 
 
 COMPARATIVE SECTIONS 
 
 SCALE ABOUT 4o'-. 
 
 . LAV* DYKE 
 
 defined, from B to D, a distance of 35 feet. Another slide at a 
 further depth of 38 feet (along the dip) causes another break, this 
 time of 8 feet only. Again at M there is a dislocation, which has 
 not gone further than to cause a derangement in the straight course of 
 the lode. We will follow the formation through the different changes 
 which it undergoes. At the 183-feet cross-cut, where it is first seen, 
 the top of the cap has been stoped away, offering to view the partial 
 
56 THE BEXDIGO GOLD-FIELD. 
 
 formation of the arched structure, which is so beautifully distinct in 
 some of the mines, the Johnson's for instance. The west leg is 
 strongly defined, and yielded well at the time it was stoped. The 
 spurs which replace the east leg were worked for a depth of 25 feet, 
 and eventually merge into the formation shown at C in Figs. 45 and 
 46. In the latter, A is the sandstone of the. overlying country ; 
 E E are spurs ; C is quartz, which includes several fragments of 
 country at D D ; B is a layer of brecciated quartzose material con- 
 taining gold, whose origin was probably the fragments of quartz 
 broken away by the fault from the west leg up above. All this 
 overlies the lava dike T, which is from 6 to 8 inches wide, and is 
 separated from the underlying sandstone by the lower wall of the 
 fault-fissure. The whole formation, inclusive of the portions C, D, 
 B, may be considered as forming the slide or fault which at a later 
 date became a passage-way for the dyke. The west leg continues, 
 well-defined and easily recognizable, fora depth of over 200 feet, in 
 spite of its being three times dislocated. From D to F it forms a 
 large body of stone,* decreasing from 12 to 5 feet in width, which 
 yielded good returns, many crushings giving 5 oz. per ton. 
 
 At the 290-feet level at the east end of the cross-cut, the first fault 
 is seen. A drift 15 feet long shows at its opposite ends the appear- 
 ance illustrated in Figs. 47 and 48. Fig. 47 shows the south end. 
 The sandstone, A, is over the line of fault, which along its course 
 has a clean wall carrying a few inches of soft selvage, S. The sand- 
 stone, C, underneath, is considerably fissured, and in the fissures are 
 the small quartz-seams, m, m. The slate, B, shows cleavage parallel 
 to the fault. Quartz is formed along the main wall, and a large 
 spur,f D, follows the bedding of the country. At the other end of 
 the drive, only 15 feet from the south face, the heading presents a 
 totally different appearance, as is shown in Fig. 48. A is sandstone ; 
 T is the dike which, in the plane of section, Fig. 47, must have 
 pinched out temporarily. D, D are quartz-veins parallel to the 
 fault. The country through which it cuts dips east. 
 
 The 291 -feet cross-cut gives a section of the lode and of both 
 slides. The lower fault is 28, and the first, or upper, 57 feet east of 
 the shaft. The second fault has more dip, but, like the first, it 
 shows a bulge of lava at one end and none at all at the other end, 6 
 
 * That is, " mill-stuff/' " quartz," or " dirt," as it is variously termed by the miners 
 in various parts. 
 
 f Were it to continue for any distance it would be called a " back," since it fol- 
 lows the line of bedding. 
 
THE BEXDIGO GOLD-FIELD. 
 
 57 
 
 feet distant, of a raise which has been put up to cut the lode. The 
 country between the two slides is much disturbed, and shows lines 
 of fissure in sympathy with the faults. It is full of flat spurs, hav- 
 ing a slight dip eastward. The country west of the faults contains 
 no spurs, but it is hard sandstone and much fissured. At 15 feet 
 west of the second fault or slide, the country begins to show a west- 
 erly dip. In Fig. 49, taken at this point, a, a are fissures parallel 
 to the faults; b, b is the bedding, indicated by a slate parting be- 
 tween two layers of sandstone ; c, c is cleavage, nearly vertical. 
 
 At the 353-feet level (see Fig. 45) the quartz has decreased to 2J 
 feet, but it is still a strong lode. Neither of the faults is to be seen, 
 as the cross-cut is not far enough east. At M there is seen an at- 
 tempt at faulting which has gone so far only as partially to dislocate 
 
 Fig. 54. 
 
 RIPPLE MARKS. 
 JOHNSON'S MINE. ioes .FT. LEVEL. 
 
 the reef. At N there is a " back," a line of parting between two 
 beds, parallel to the lode, which goes up as far as the second fault, 
 where a formation of spurs is found on both sides of it. This is the 
 last we see of the reef, which decreases rapidly in size and becomes 
 unprofitable, the dip taking it across the shaft before reaching the 
 level of the 451 -feet cross-cut. 
 
 This cross-cut intercepts at O, Fig. 45, the back which we saw at 
 N, in the 353-feet crass-cut. It is well-defined and continues under 
 foot. The cross-cut ends in a very well-formed saddle, P, Q, K, 
 which is shown in greater detail in Fig. 50. The outline is sug- 
 gestive of a double contortion. The cap makes a very clean curve. 
 Sandstone, A, overlies the quartz, both being penetrated by the dike, 
 T. Underneath the quartz is slate, B, in which are the spurs at C, 
 which replace the east leg. The west leg is divided into two por- 
 tions, separated by slate. Going south, they are wider apart. The 
 
58 THE BENDIGO GOLD-FIELD. 
 
 slate under the cap shows lines of bedding, and its division from the 
 underlying sandstone forms a clean, very beautiful arch. 
 
 The lava dikes, which form so marked a feature of the section, 
 Fig. 45, have many points of interest. A dike (varying from 12 to 
 20 inches in size) cuts through the cap at the 183- feet level. It has 
 a slight eastern dip which, on striking the quartz, is changed for the 
 dip of the west leg, through which it passes (it is now 6 to 8 inches 
 wide) until meeting the fault, which it then follows, as the line of 
 least resistance. It underlies the formation at C, and is last seen in 
 the 294-feet cross-cut. 
 
 Another dike (4 inches only in width) comes down, keeping com- 
 pany with a " leader," cut near the shaft at the 294-foot level. It 
 is probably a branch from that which follows the No. 2 fault, as 
 seen at H, Fig. 45. This latter dike is probably again seen in the 
 lava which strikes at Q against the saddle, following the west leg 
 for a few feet, and then cutting across the quartz to continue its 
 course through the sandstone of the center-country. 
 
 At the 353-feet level, near the plat, is seen the dike shown at K, 
 which is also illustrated in Fig. 51. There it is seen that it cuts 
 across the bedding (A, A), following a fissure, and that it appears to 
 die out in small threads at M and N. 
 
 About 5 feet east of this point there is another dike, shown at Z, 
 Fig. 45, which is 9 inches thick, and is continuous so far as it is 
 seen. 
 
 The two faults encountered in this mine are found again in the 
 neighboring mines. They get wider apart to the north. In the 
 Carlisle they are divided by 40 feet of country, while southward 
 they approach each other, and in the Victory and Pandora Com- 
 pany's ground they are seen to cross. I saw a section of the upper 
 workings of the Pandora in which these same faults are readily 
 recognizable, though they had been misinterpreted by the draughts- 
 man. In Figs. 52 and 53 are given two comparative sections. Fig. 
 52 is a sketch reproducing on a smaller scale the old drawing to be 
 seen in the office of the company. Fig. 53 indicates what appears 
 to me to be the real situation. In Fig. 52 S is called the leader, 
 G the cap of the saddle, H the west leg, and K the east leg of 
 another more complete formation. The lava dike follows a slide 
 which has an irregular course' through the two bodies of quartz. 
 Just below the 234-feet cross-cut the legs are bent. 
 
 Compare this with the section of the Unity. The two mines ad- 
 join, and we know that southward the two faults or slides are ap- 
 
THE BEXDIGO GOLD-FIELD. 
 
 59 
 
 
60 THE BENDIGO GOLD-FIELD. 
 
 preaching each other. Now refer to Fig. 53, where G is the cap of 
 a formation, which, like that of the Unity, of which it is undoubt- 
 edly an extension, has no east leg, while the west leg, H, is faulted 
 by the two slides, A, B and C, D. In the Unity we saw that 
 the lower fault was flatter than the other it is so here, where 
 they cross. Below the 234-feet cross-cut we have a partial dis- 
 location due to the fault, E, F, similar to that seen at M in the 
 Unity (Fig. 45). The portion, N, of the formation corresponds 
 to that shown at C in the Unity section, while the quartz which 
 accompanies the dike at L, L is similar to that which usually 
 follows the line of the fault, as indicated in Figs. 47 and 48. 
 
 The question arises, which way was the movement ? The only 
 evidence in reply is that obtained by noting which part of the 
 country-rock is most shattered. In the Unity the country between 
 the faults has been fissured, that west of them less, and that east of 
 them more. That the west country has not been subjected to much 
 movement is shown by the regularity of the formation in the 451- 
 feet cross-cut. It seems to me, therefore, that the movement was an 
 upward one on the part of the country east of the first fault, accom- 
 panied by a lesser movement in the same direction by that which 
 lay between the two faults, decreasing westward until at M it had 
 almost died out. 
 
 OTHER INDICATIONS OF STRUCTURE. 
 
 Having given a description of some of the typical mines of the 
 district, it remains for me to add such other evidence gathered in the 
 various mines as bears most directly upon the structural relations of 
 the ore-deposits. 
 
 Of the evidence offered by the underground workings, none is 
 more beautiful than the ripple-marking at the Johnson's mine. This 
 is spen at its best in the 1065-feet north level. Figs. 54 and 55, are 
 sketches made underground to illustrate it.* 
 
 Fig. 54 was taken 5 feet north of Fig. 55. The crests of the 
 waves are 3 to 3J inches apart, the rock in which they occur is a 
 very hard sandstone, shading into a quartzite, and forms the footwall 
 of the reefs. On breaking the face the markings cannot be followed 
 into the next layer of sandstone, this being due to the metamorphism 
 which the rock has undergone, and its cementation along the lines 
 
 * It requires photography to do justice to this very interesting occurrence. All 
 I can do is to give roughly an idea of this striking evidence of the bedded character 
 of the reefs. 
 
THE BEXDIGO GOLD-FIELD. 
 
 61 
 
 of original deposition. The preservation of the ripple-marks is due 
 to the fact that the sandstone face which shows them was overlain 
 by a soft slate, which has since in part been replaced by the quartz 
 of the lode. The markings can be followed for 100 feet in height, 
 and for more than 200 feet in length. The reef of which this is the 
 foot-wall dips east about 70 ; it was in this part of the mine richly 
 gold-bearing, and it was found in breaking the quartz* that it 
 broke with difficulty, owing to the resistance offered by the pro- 
 jections of the corrugations which were so striking a feature of the 
 stopes.f 
 
 Fig. Gl. 
 
 CONTORTIONS IN SANDSTONE. 
 
 LAZARUS. 125O LEVEL 
 
 % NATURAL SIZE. 
 
 These ripple-markings were in east country. At the 550-feet plat 
 in the latter mine, immediately behind the "west reef," there is a 
 
 f The ripple-marked wall formed "the shooting-wall," that is, it was utilized in 
 blasting as the Hue along which the quartz detached itself most readily. 
 
 | Soon after my third visit to Sandhurst, I saw an almost exact duplication of 
 these markings in the sands of to-day. It was in New Zealand. We were trawling 
 by moonlight ; and while pulling in the net I noticed that the sand forming the bot- 
 tom of the shallow water in which we stood was covered by a series of ripple-marks, 
 whose distance apart and little irregularities resembled those which I had seen in 
 the Johnson's mine ; but these on which I stood were of to-day, those were laid 
 down in the estuaries of the Silurian seas ; these were soft and yielding, while those 
 had been consolidated into a quartzhic sandstone, now one thousand, and at one 
 time manv thousand feet below the surface. 
 
62 THE BENDIGO GOLD-FIELD. 
 
 bed of sandstone whose under side shows a cast of ripple-markings, 
 in other words instead of getting ridges, you get hollows, the true 
 ripples on the underlying bed are not to be seen, but the sandstone 
 which was deposited upon it still retains the impression, the nega- 
 tive of the face of sand which it overspread. 
 
 At the Lazarus mine is found the formation shown in Figs. 56 to 
 61, reproduced from sketches taken in some old stopes at the bottom 
 of a winze leading from the 1250-feet east level. Fig. 56 gives a 
 general view of the saddle. A A is the cap, which is not at all 
 regular in outline, and both above and below breaks up into spurs. 
 The east leg is cut off by a fault, on which the winze was sunk. 
 The manager informed me (the ground is filled up now), that in 
 stoping it, was found that the west leg also was cut off by this same 
 "slide." 
 
 The remarkable feature of this formation is the development of 
 radial cleavage. In the drawing, a a are lines of cleavage, b b are 
 structural lines parallel to the bedding. The bedding is for the 
 most part completely obliterated by the cleavage. On careful search 
 the lines of original deposition can be traced, but with difficulty and 
 only partially. The [most striking evidence, however, is that of 
 some extremely delicate but distinct markings found in the sand- 
 stone underneath the arch of the saddle, markings which prove in 
 miniature the contortion to which the rock has been subjected. They 
 are shown in their natural size in Fig. 61,* and their position as 
 regards the saddle is indicated by X in Fig. 56. The rock in which 
 they occur is a very fine-grained sandstone, the contortions being 
 rendered distinct by the alternation of dark- and light-gray laminse. 
 
 Fig. 57 was taken in the winze. The slide S is 5 feet wide, and 
 the slaty materials of which it is composed are arranged parallel to 
 the bounding walls. A small quartz-seam B is faulted,f the throw 
 being about four inches. It is accompanied by a narrow band of 
 black slaty filling. The edges of the beds of the country are bent 
 and broken at their contact with the walls of the "slide" at D. 
 
 Fig 58 is taken in center-country, under the saddle. A is a vein 
 of quartz, a spur, filling one of the many fractures produced in the 
 bending of the beds; a a are lines of cleavage, at this point very 
 marked; b b are quartz-seams arranged along the structural lines, 
 
 * This might be taken as the cross-section of a mountain range ; and certainly 
 these foldings, though only covering a few inches, are typical of the plication which 
 has produced mountain ranges. 
 
 f A fault within a fault. 
 
THE BENPIGO GOLD-FIELD. 
 
 63 
 
 which are parallel to the bedding. This may be called " secret bed- 
 ding," since the fractures are doubtless in sympathy with the bedding 
 and along lines of original deposition, only now made visible by the 
 fissuring through which relief was obtained at the time of the plica- 
 tion of the rocks. 
 
 Fig. 59 is in east-country, just above the slide or fault. C is 
 slate ; D, slaty sandstone ; E, sandstone. A and B are quartz-spurs 
 thrown off by the east leg. At F the cleavage is twisted. 
 
 This formation, the several portions of which have been briefly 
 described, throws a good deal of light upon the structure character- 
 istic of saddle-reefs. 
 
 Evidence of the structure of the district can be obtained without 
 
 Fig. 62. 
 
 going underground, since large open cuts are numerous along the 
 main lines of reef. Several sketches made in the surface-excava- 
 tions are shown in Figs. 62 to 66, inclusive. Figs. 62 and 63 were 
 both taken behind the engine-house of the " 180" mine on Victoria 
 Hill. Fig. 63 shows where the quartz has been for the most part 
 removed, leaving an arch overhead. C is debris; D, slaty sand- 
 stone; while A is a lava dike, the same dike which is repeatedly 
 seen underground and which forms one of the most striking features 
 of the deepest workings, as shown in Fig. 14. 
 
 Fig. 62 is about 100 yards south of Fig. 63, and shows the 
 southern continuation of the same anticline. At B, the bedding is 
 very distinctly to the west, the rock being "corduroy," which 
 weathers very slowly. The country about the apex of the saddle 
 
64 THE BENDIGO GOLD-FIELD. 
 
 has undergone considerable alteration, and only traces of the original 
 bedding are now to be seen. 
 
 Fig. 64 is taken in the vicinity of the New Red, White and Blue 
 mine. The saddle is very sharp and distinct. C is an old drift, 
 while D consists of material which has been filled in. 
 
 Figs. 65 and 66 will appear curious. They are sections of the 
 same anticline, taken from the opposite sides of a narrow cutting. 
 The space covered is only 7 to 8 feet in width.* The wavy lines 
 are marked by small seams of quartz which follow the contorted 
 bedding in the country-rock. The nearly vertical veins are inter- 
 esting as indicating the fractures which took place along the axis of 
 the fold. 
 
 This closes the evidence which I offer as bearing most directly 
 upon the structural relations of these very remarkable ore-deposits 
 of Sandhurst. Out of the large number of notes and sketches made 
 by me while underground, I have endeavored to place before the 
 Institute those which seemed most directly pertinent. Instances in 
 which geology, particularly structural geology, and practical mining 
 are so closely allied can rarely be found. The close relation which 
 they bear to one another is hardly understood by the busy under- 
 ground managers of the mines, save in a few very noteworthy cases ; 
 and this is scarcely to be wondered at, seeing that almost without 
 exception the references to and the descriptions of the Sandhurst 
 mines, meager as they are, on the part of geologists, engineers, 
 etc., are quite incorrect; their authors having confounded the bed- 
 ding with the cleavage. Misled by the cleavage, "its mysteriously 
 deceptive harmonies with the stratification "f on tne east side of the 
 saddles, and its often complete obliteration of the bedding on the 
 west side, they have considered that the east leg did conform to the 
 bedding, but that the western cut across it, that is, the ore-deposits 
 were " saddles " in name only. 
 
 There is one noteworthy exception, namely, a short note which 
 appeared in the quarterly report of the Mining Department of Vic- 
 toria, for December, 1888, by E. T. Dunn, formerly government 
 geologist of the Cape Colony. In that note attention is directed to 
 
 * There are several large open cuts behind the Victoria quartz mine, and having 
 noticed that in different parts of the workings the country dipped east and west, I 
 hunted for the turn-over of the saddle. It was only a ter a second search that, in 
 leaving the old excavations by a narrow road-cutting, I found what is represented 
 iu ray sketches. Recent rain had rendered the structure beautifully distinct. 
 
 f Ruskin, in Schisma Montium, Deucalion. 
 
THE BEXDIGO GOLD-FIELD. 
 
 65 
 
 this point. Had it come under my notice previous to going to 
 Sandhurst, I should have been spared much of the difficulty which 
 I experienced before the true nature of the deposits became manifest.* 
 
 That the typical ore-deposit of the Sandhurst gold-field is a true 
 anticline there can be no doubt. As already pointed out, the saddle 
 is not the only formation in which the gold-quartz is formed, since 
 the spurs, backs, lodes, etc., have at all times been responsible for a 
 very large share of the output; but the saddle is the distinctive 
 form to which the others are for the most part accessory and sub- 
 sidiary. 
 
 The ripple-marks frequently observed underground are incon- 
 
 Fig. 63. 
 
 trovertible evidence of the original position of the beds. That, for 
 instance, the east leg of the big saddle in the Johnson's follows the 
 true line of stratification, is amply proved by the very beautiful 
 markings seen in the 1060-feet level. Similarly, ripple-marks are 
 seen on the faces of beds dipping west. Other no less conclusive 
 though less striking evidence has been given in the descriptions of 
 the various mines. 
 
 Mining is a commercial business and not a scientific pursuit. The 
 le on its dip ceases whenever the quartz which it 
 
 following of a 
 
 * In visiting Sandhurst one usually visits first the more famous mines on Victoria 
 Hilt, such as the celebrated *' 180" mine and others near it. It so happens that in 
 these mines that the structure of the country-rock is most hidden, because the 
 cleavage is most highly developed. The smaller mines at the other end of the field 
 show the true character of the ore-deposits far more clearly. Among the latter the 
 South Xew Chum has been described here. 
 
 5 
 
66 THE BENDIGO GOLD-FIELD. 
 
 contains is no longer auriferous; and as a consequence the mine- 
 workings rarely disclose the ultimate limits of the lower portions 
 of a saddle-formation. Lower cross-cuts will intercept a thin but 
 pronounced parting in the country, a "back" which could be traced 
 upward until it formed the boundary of a big lode or "reef;' 7 or 
 they may cut through a "spur," which if followed would be found 
 to lose itself in an east or west leg, the distinction in the two cases 
 being solely that of conformity with the bedding of the country- 
 rock. Where the legs, as parts of a saddle-formation, end, and 
 where they become one or other of the various types of cross-fissure, 
 no man can say. It may be considered that whenever they lose 
 their true character as bedded veins they cease to be the lower por- 
 tions of a saddle; but the distinction is theoretical and arbitrary; 
 for the gold knows no difference and is found in both. 
 
 The same system of fracturing may produce in one part of the 
 mine a " big reef," a leg of a saddle which is highly auriferous, while 
 overhead* in another part it may be a mere fissure, carrying no 
 quartz, and lined only with a thin seam of black clay, which cuts 
 across the country overlying the saddle. Again at a lower depth, 
 while still retaining its characteristics as a portion of a saddle, it 
 may carry quartz which is not sufficiently gold-bearing to work, or 
 it may slowly degenerate into a " leader," if the quartz continue, or 
 a "back 7 ' whenever that has ceased, becoming nothing more than a 
 parting between a bed of sandstone and a bed of slate. Again, it 
 may eventually cross the bedding, cease to be a true " leg," and 
 become a gold-bearing "spur" ; and finally it may be traced into a 
 mere thread of white quartz, one of many, traversing a bed of sand- 
 stone. 
 
 To make nice distinctions would be arbitrary and out of accord 
 with the facts; the same fissure in one mine plays many parts. 
 
 While, therefore, I would not say that the legs of a saddle-forma- 
 tion never go astray from their correct course between the bedding 
 planes, such an occurrence would be found only when they are begin- 
 ning to die out, and does in no way modify our view of the true nature 
 of the "saddle-reef," which, notwithstanding interesting local varia- 
 tions of structure, is a distinct type of ore-deposit essentially travers- 
 ing the Silurian slates and sandstones in conformity with the bed- 
 ding, and forming along the anticlinal undulations of the enclosing 
 country those bodies of gold-bearing quartz which are the most pecu- 
 
 * See Fig 21, where an instance of this kind is shown in the South New Chum. 
 
THE BENDIGO GOLD-FIELD. 
 
 67 
 
 liar feature of the mining industry and the most valuable depository 
 of the wealth of the Bendigo gold-field. 
 
 MINE-MANAGEMENT. 
 
 Fig. 67 is a view of the New Chum line of reef from Eaglehawk, 
 copied from the quarterly mining report of the Victorian govern- 
 ment. 
 
 There are at present engaged in the exploitation of the mines 143 
 companies and 21 tribute-parties, the former including four private 
 mines. The gold-field has been developed by the energy of its own 
 people, the amount of outside chiefly Melbourne money invested 
 being comparatively small. Sandhurst has profited greatly by the 
 enterprise and success of one or two mine-owners, such as the late 
 I. B Watson and the present owner of the " 180 " mine ; but its 
 development has been retarded, on the other hand, by the prevalence 
 
 Fig. 64. 
 
 of one of the worst systems of company-financiering. The actual 
 management of the mines, both above and under ground, is in the 
 hands of capable and careful men ; but they are hampered by the 
 fact that reserve capital is almost unknown. Of the 28 dividend- 
 paying companies of 1890, four appear also on the call list. That 
 is to say, these four companies both levied calls and disbursed divi- 
 dends during the year. A series of fortnightly sixpenny dividends 
 may be followed by a number of fortnightly calls, supplemented 
 by a bank-overdraft a state of affairs which may swell the volume 
 of business and keep a number of clerks employed, but which, to 
 say the least, is quite unbusinesslike and highly prejudicial to the 
 proper development of mines which require extensive and systematic 
 exploration. The fortnightly dividend is the bane of Bendigo. 
 Whenever a rich saddle-formation is discovered, all haste is made to 
 open it up; as soon as the cross-cuts and drifts have intersected the 
 ore, stoping is at once commenced, the quartz being broken away as 
 
68 THE BENDIGO GOLD-FIELD. 
 
 rapidly as possible, while all development-work is for the time prac- 
 tically suspended. The results of a few crushings enable the di- 
 rectors to pay off the bank-overdraft and enter upon the regular 
 announcement of dividend after dividend, at intervals of a week if 
 a fortnight seems too long ! No part of the profit is laid aside as a 
 reserve-fund, and, as a consequence, when the ore-body is worked 
 out, the dividends abruptly cease, and the bank-account is overdrawn 
 to pay running expenses, until it is necessary to call upon the share- 
 holders for fresh assessments. This foolish round of alternating 
 surplus and deficit, of squandering, borrowing and taxing, has gone 
 on year after year, notwithstanding some of the more thoughtful 
 managers are fully aware of its harmful character. The result may 
 be seen in the cases of mines which divided in profits a few years 
 ago sums varying from 100,000 to over 250,000, and are now 
 almost idle for want of funds to open up new ground. The imme- 
 diate distribution of profits leads to a continual change in the per- 
 sonnel of the shareholders, so that a mine when poorest maybe owned 
 by men who had no share in the property when it was most produc- 
 tive. Mining is thus brought down to the level of mere specula- 
 tion an evil not unknown, under different forms, in other districts, 
 and certain everywhere to cripple the legitimate industry of mining. 
 The management of the mines is controlled by the directors, the 
 " legal manager " and the " mine-manager." Since, as a rule, these 
 are all resident in the vicinity, and exercise more or less direct super- 
 vision, it is largely a question of personal influence which is in the 
 ascendant. A mine-manager, as known to English companies, 
 that is, a manager of all the mining work, or a superintendent, as 
 known in the United States, is not found in this gold-field. The re- 
 sponsibility of superintendence is much scattered. The " mine-man- 
 ager" receives the pay of a foreman about 20 or $100 per month. 
 The " legal manager " is the business man and book-keeper. The 
 directors control the policy of the company, and also do much of 
 the work often delegated elsewhere to a consulting engineer. Such 
 a thing as a trained mining engineer is not to be found upon the 
 staff of any of the companies ; and the work done, as a conse- 
 qence, lacks progressive character. The actual mining work under 
 ground leaves nothing to be desired. It is carried out under the eyes 
 of men whose superiors as miners cannot be found ; but a want of 
 system is to be observed in the development of the mines. 
 
THE BEXDIGO GOLD-FIELD. 
 
 TREATMENT OF THE ORE. 
 
 69 
 
 The handling of the ore in the mills is far from satisfactory. The 
 explanation is simple. Of the managers of 27 mines which I exam- 
 ined, the names of 25 indicated the fact that they hailed from the west of 
 England, while the other two, though native-born, were of the same 
 stock. The men of Doon and Cornwall are miners second to none; 
 but they make the most unprogressive of mill-men. 
 
 The gold-ore of this field belongs to the simplest type of the free- 
 milling class. As a rule, it consists of white quartz carrying a very 
 small proportion (from 0.25 to 1 per cent.) of arsenical pyrites. Iron 
 and copper pyrites, blende and galena are also frequently present, 
 but in very inconsiderable amount. The gold varies greatly in 
 its mode of occurrence, but is usually coarse, in the rich ore 
 
 Fig. 65. 
 
 almost invariably visible, and of uniformly high purity, being 
 worth 3 17s. Od. to 3 19s. Od. per ounce pure gold being worth 
 at the London mint 4 4s. lljd. 
 
 The quartz itself is usually dead-white, with an appearance 
 which, in California, would be considered most unfavorable to the 
 presence of gold. It has a splintery fracture, rendering it easy 
 to break. The mill-stuff consists of the quartz mixed with from 
 one-third to over one-half of vein-filling and country-rock, which 
 varies. The ratio in amount of slate to sandstone and the con- 
 sequent hardness of the material to be crushed is constantly 
 changing. It is the fragments of excessively hard quarzitic sand- 
 stone which cause most wear and tear to the milling-machinery. 
 
 Stamp-milling of the simplest kind is the method employed to 
 extract the gold. The mills are constructed on the spot by excellent 
 
70 THE BENDIGO GOLD-FIELD. 
 
 local foundries, at a price usually far below that which is in the 
 western United States. A first-class stamp-mill of 40 heads, engine 
 and shed included, with shaking- tables but without rock-breaker or 
 automatic feeder, can be contracted for at from 6000 to 7000 
 or about $30,000. The battery-frame is generally of iron. 
 Whether this mode of construction is advantageous to the work 
 of the mill is open to doubt. Both the breaking and the feed- 
 ing of the ore is done by hand, and in this respect the mills of 
 Sandhurst, in common with most of the colonial batteries, are a 
 standing disgrace to the modern mining industry. Inside plates are 
 not used. Plain, not electro-silver-plated, copper plates are used to 
 arrest the gold on amalgamating tables. Blankets precede the sha- 
 king-tables, which have the end-shock,*and are -a variation of the 
 much-used Rittinger type- 
 
 The stamps weigh from 800 to 950 pounds per head ; drop 8 to 9 
 inches, usually 70 to 75 times per minute, and crush, as a rule, about 
 2 tons per head per 24 hours. The depth of discharge or issue va- 
 ries widely, but the average is about 3 to 3J inches. The screen or 
 , grating is made of slot-punched Russia iron, having 120 to 180 holes 
 per square inch. The bullion is from 940 to 960 fine. 
 
 The percentage of concentrates varies from J to 2 per cent, per 
 ton of ore milled. These are treated at the local " pyrites works," 
 of which there are several ; the method of extraction varying from 
 arrastra to chlorination. The charge is generally 3 per load of 25 
 to 30 cwt. 
 
 A discussion of the milling-practice in detail and from a technical 
 standpoint would be interesting and instructive ; but I must content 
 myself in the present paper with the above indication of its general 
 character. 
 
 GOVERNMENT ASSISTANCE. 
 
 The serious decline in the output of gold in Victoria has led to 
 the introduction of government assistance to mining. Whether this 
 course has done good or harm is a vexed question. In the hope of 
 giving renewed vigor to the mining of the colony, the Victorian gov- 
 ernment has distributed for several years sums amounting to 80,- 
 000 per annum, the intention being to encourage exploration. A 
 miner, a group of miners, or a company needing funds to proceed 
 with a cross-cut, a level or a shaft to cut a known lode, or to explore 
 for a suspected one, makes application before a local committee, 
 elected by the miners, and called the Prospecting Board. This body 
 
THE BEXDIGO GOLD-FIELD. 
 
 71 
 
 reports it favorably or otherwise to the Secretary for Mines. Out 
 of a large number of applications submitted, the most promising and 
 deserving are selected. The terms of the grant are " pound for 
 pound ;" that is, for a grant, say of 000, there must be another 
 500 furnished by the applicants, making 1000 available for the 
 particular work (and that only) designated in the application. 
 
 Such prospecting-grants are now generally condemned. Beyond 
 question the system has completely failed to bring about fresh dis- 
 coveries by prospecting. I have seen its operation in different parts 
 of the colony, particularly in the mountainous districts which have 
 been, as yet, least prospected ; and the result appears to have been 
 only to pauperize mining. It is always understood, that should the 
 subsidized party succeed in placing the assisted mine in a dividend- 
 
 Fig. 66. 
 
 paying condition, the amount of the grant should be repaid to the 
 government from the first profits. This has been done in instances 
 so few as to be remarkable. 
 
 On the other hand, this annual dole has done harm by encouraging 
 that improvidence, whether of companies or of individuals, which is 
 the chief hindrance to systematic mining. It has long been a bad 
 feature of colonial mining, as I have shown above, that no portion 
 of the profits is put aside as a reserve to carry on the work of devel- 
 opment during lean years; and this prospect ing-grant encourages 
 that evil. Having been too eager for dividends to provide for the 
 time when the reef might " pinch out," the mine-owners fall back 
 upon the fatherly assistance of a benevolent government. Mining 
 is a business ; and if a mine has sound prospects of success it is very 
 rarely indeed that the money is not forthcoming to carry on the work 
 of development. The money thus distributed could be far better 
 
72 THE BENDiGO GOLD-FIELD. 
 
 employed in the endowment of a good central mining school, to re- 
 place the second-rate technical institutions which at present usurp 
 the name. 
 
 Prospecting with the aid of the diamond-drill may be said to form 
 a part of the scheme of governmental assistance. 
 
 During the past year, some interesting work in this direction has 
 been carried out at Sandhurst. At the invitation of Mr. George 
 Lansell, who offered to provide the necessary compressed air and 
 other facilities, the Victorian mining department decided, toward 
 the end of 1889, to put down a series of bore-holes from the bottom 
 of the celebrated "180" mine, which had then reached a depth of 
 half a mile. The machine used was Leschot's patent, manufactured 
 in San Francisco, the core being 1 inch in diameter. Four holes 
 were put down, having an aggregate length of 2335 feet. The record 
 of each was as follows : 
 
 No. 1. Bored horizontally eastward from a point in the 1300-feet 
 level 197 feet east of the shaft. Length, 683 feet. Commenced 
 January 16, and finished March 17, 1890. Alternating beds of slate 
 and sandstone were intersected with occasional thin seams of quartz. 
 No information of any value was obtained, and. the drilling was 
 stopped by a strong flow of water, preventing the sufficiently rapid 
 removal of the sediment from the bit. 
 
 No. 2. Bored downward to a depth of 453 feet, with an inclina- 
 tion of 9 inches in 16 feet, from center-country in the 2600-feet 
 cross-cut. The ground varied greatly in hardness, and finally be- 
 came broken up, when water, having a temperature of 97 F., and 
 under a pressure of 110 pounds per square inch, was struck.* 
 
 * While the diamond-drill was at work, a good deal of notice was drawn to the 
 heat of the water encountered in boring at the bottom of the "180" mine. The 
 thermometer showed an average of 97 F., and at one time a maximum of 107 was 
 reached, as recorded by three instruments. This was at a depth of 450 feet below 
 the 2600-feet level or 3050 from surface. This temperature is by no means sur- 
 prisingly high. The average annual mean temperature at Sandhurst is 60.2 F., 
 and allowing for an increment of 1 for every 55 feet, we should expect at 450 feet 
 a temperature of about 115 F, which agrees fairly well with the facts as disclosed 
 in the "180" mine. However, the matter was considered of sufficient interest to 
 induce a thorough examination by the government analyst, Cosmo Newberry, of the 
 contents of the water so obtained. To this end, two and a half tons of the water was 
 evaporated down to 10 gallons, care being taken to keep out impurities, and 3125 
 grains of solid matter remained, mostly carbonate of iron. Assays were made, but 
 no gold was obtained, though a trace of a metal of the platinum group was given by 
 the precipitated material. The results were disappointing, in failing to throw light 
 on the occurrence of the gold in the quartz formation. The annual mining report 
 of the department says that a further (optical) examination is to be made. 
 
THE BEXDIGO GOLD-FIELD. 
 
 73 
 
74 THE BENDIGO GOLD-FIELD. 
 
 No. 3. Bored at a slight inclination below horizontal for 636 feet 
 westward from the plat at the 2500-feet level. It intercepted several 
 veins of quartz, the largest of which, however, was only 9 inches 
 thick. 
 
 No. 4. Bored nearly vertical (inclining only slightly to the west) 
 at a point 30 feet west of No. 2, in the 2600-feet cross-cut, to the 
 depth of 562 feet below the level, or 3162 feet below the surface. 
 It passed through about 200 feet of sandstone, as well as several 
 beds of quartzitic sandstone, and cuts several series of small quartz- 
 veins. Hot water under considerable pressure interfered with prog- 
 ress, as in the case of No. 2, though the temperature in this instance 
 was lower. 
 
 The result of these borings was practically nil. No discoveries 
 of importance were made; and it is doubtful whether the drilling 
 had even a negative value in proving the absence of auriferous 
 quartz in that portion of the country which it was attempted to test. 
 If relied upon as a prospecting instrument under such conditions, the 
 diamond-drill is likely to do serious harm by causing the condem- 
 nation of large areas of what may be good mining ground. In 
 strata possessing regularity and continuity, such as the coal-seams; 
 in the determination of the thickness, of certain beds overlying 
 known deposits, such as the sheets of basalt over the "deep leads" 
 of California ; in the tapping of old workings which are under water ; 
 in the measurement of large ore-bodies (as was done in the case of 
 the great bonanza at Virginia City); and in many other instances, 
 no doubt, the diamond-drill, if judiciously employed, is a most use- 
 ful aid to the miner; but in quartz-mining in general,. and in such 
 districts as Bendigo in particular, it is often likely to do irretrieva- 
 ble harm by fostering delusive hopes on one hand or unnecessary 
 discouragement on the other. 
 
 To support this view, it is not necessary to go outside Victoria. 
 In the discovery of gold-seams and the exploration of deep beds of 
 auriferous alluvium, the diamond-drill, under the judicious direction 
 of the government geologist, has been very successful ; but it has 
 proved a very mixed and doubtful blessing indeed to quartz-mining. 
 In the Sandhurst district, the peculiar structure of the "saddle- 
 reefs," and the comparatively short extent of most of the bodies of 
 gold-bearing quartz, are extremely unfavorable for tests of this 
 character. This is particularly true of horizontal holes, which 
 might penetrate the immediate neighborhood of rich formations 
 without discovering them. If the drill is to be used at all, the 
 
THE BENDIGO GOLD-FIELD. 
 
 75 
 
 dangers attendant upon its use should be minimized by planning a 
 series of holes close together, so as to test thoroughly and satisfac- 
 torily, at least a small portion of ground. 
 
 DIMENSIONS OF CLAIMS. 
 
 Among the interesting features of this gold-field is the small area 
 of the claims. The following table gives the areas of eleven con- 
 tiguous properties on the New Chum " line of reef." The claims 
 are of very irregular shape (see Fig. 7), and in some cases the 
 length of the tract is much greater than the figures given, but for 
 purposes of comparison the measurement is taken along the sup- 
 posed line of the New Chum reef. 
 
 Areas and Depths of a Group of Mines, Victoria Hill, Bendigo. 
 
 NAME OF MINE. 
 
 Area of the 
 Property. 
 
 Length along 
 ftrike 
 of reef. 
 
 Depth of 
 Shaft, 
 
 Ironbark Quartz 
 
 Acres R. P. 
 4 1 36 
 
 Yards. 
 220 
 
 Feet. 
 2140 
 
 Victor! a Consol s 
 
 22 3 15 
 
 259.6 
 
 2162 
 
 Gt. Central Victoria 
 
 10 1 17 
 
 250.8 
 
 1970 
 
 Victoria Reef Quartz 
 
 7 25 
 
 140.8 
 
 2302 
 
 Lansell's "180" 
 
 14 1 12 
 
 171.6 
 
 2641 
 
 North Old Chum 
 
 2 1 25 
 
 88 
 
 2310 
 
 New Chum and Victoria 
 
 13 3 12 
 
 710 
 
 2300 
 
 Old Chum 
 
 11 2 32 
 
 710 
 
 2208 
 
 Lazarus Co . . "i 
 
 
 83.6) 
 
 
 Lazarus No 1 / 
 
 22 1 7 
 
 764.6 J 
 
 2173 
 
 Lansell's " 222 " 
 
 16 19 
 
 994 
 
 2100 
 
 
 
 
 
 It will be seen that the average area of each property is but a 
 little over 11 acres; that one of the claims, having an area of only 
 two acres, has workings over 2-300 feet deep ; and that the ten shafts 
 belonging to eleven companies have an average depth of 2230 feet, 
 and are distributed over a total distance of less than a mile along 
 the strike of the lode. The small area of these properties is prima- 
 rily a relic of the early days when the claims consisted of twenty 
 yards "along the line of reef" for two men. A certain amount of 
 consolidation followed on the initiation of deep mining; but this was 
 limited to the immediate needs of the time, and has long since been 
 
76 THE BENDIGO GOLD-FIELD. 
 
 outgrown by the very extensive exploration of more recent years. 
 A circumstance permitting the working of these small areas is the 
 absence of any large quantity of water in the mines. In the par- 
 ticular group of properties cited above there is not a single pump. 
 The little water that finds its way into the workings is raised with 
 tanks alone. At the "180," the deepest mine in Australia, 3000 
 gallons are hoisted per 24 hours. 
 
 The largest areas held by mining companies are as follows: 
 
 
 
 Acres. Rods. Perches. 
 
 Hercules and Energetic, .85 3 17 
 
 Johnson's Reef, ."-./:- . 71 2 21 
 
 Catherine Reef United, . . ^.' . . '. '. 65 3 12 
 
 New Red, White and Blue Cons 'V. 41 3 27 
 
 Garden Gully United, . . . . . ... 41 3 
 
 It is seen that even the largest properties are of a size which would 
 be considered small in many districts. It must be admitted, how- 
 ever, that the holding of an extensive acreage does not, in Sand- 
 hurst, necessarily mean extensive explorations; since, by reason of 
 the want of working-capital, most of the companies confine their 
 operations to such portions of their holdings as are in the immediate 
 vicinity of the main shaft. This bad feature of the mining work 
 will be slowly overcome, no doubt, by further consolidation. The 
 twin Lazarus Companies have set a good example by sharing one 
 working-shaft; and a recent attempt to consolidate the North Old 
 Chum, New Chum, and Victoria, though unsuccessful, may be taken 
 as an indication of the growth of a proper appreciation of the neces- 
 sity for such measures. 
 
 DEEP MINING. 
 
 The list of deep mines just given suggests the general subject of 
 deep sinking, a feature of mining at Sandhurst to which reference is 
 often made in the colonies. This practice owes its beginning to the 
 "180" mine* When the mine was purchased in 1873, the shaft 
 was only 400 feet deep, but the neighboring North Old Chum, New 
 Chum, and Victoria, Old Chum, and Lazarus, were doing well on a 
 reef which traversed the mines from 600 to 700 feet below the sur- 
 face. The sinking of the shaft of the " 180 " mine was commenced. 
 At about 600 feet 120,000 of gold was won. Sinking was con- 
 tinued in the face of much ridicule, and slowly the mine attained a 
 depth which in those days was considered very geat. Much money 
 was expended without any return, until, in 1883, after ten years of 
 
THE BEXDIGO GOLD-FIELD. 77 
 
 steady development, the top of the saddle was cut in the 1548-feet 
 level. An ore-body of extraordinary richness was uncovered, and 
 stoping began ; but the sinking of the shaft continued. The Mel- 
 bourne Argus of that day said : " The success of this venture in deep 
 mining decides the prosperity of Sandhurst for a further decade at 
 least." The mine is now ^641 feet deep. The success of deep 
 prospecting having been proved in this trial-instance, imitators were 
 not wanting; and there were soon several mines competing for the 
 record of greatest depth. Deep sinking developed into a craze 
 which seemed at one time likely to do serious injury to the proper 
 exploitation of the mines. The result is seen to-day in the 18 
 shafts, each of which has a depth of over 2000 feet. 
 
 Among the causes of this state of things the structure of the ore- 
 deposits may be named first. The Bendigo miner has an embarrass 
 de richesse in the matter of quartz- formation. Should a saddle be 
 intercepted, the first crushing from which yields scarcely enough gold 
 to pay expenses, it is soon left on one side in the search for the next 
 formation, which is usually not far below. Below, not ahead, for, 
 instead of longitudinal extension, the miner in this gold-field looks 
 for a vertical repetition of the auriferous formations. Did each mine 
 uncover one lode only, there would be more extensive and patient 
 prospecting at any one given level ; but, as matters stand, the ex- 
 ploration is not so thorough as it should be, for the reason that it is 
 divided among several levels. 
 
 The most potent cause is, however, seen in the success of the deep 
 mines. Deep sinking has not drawn blanks alone, but many prizes, 
 such as the bonanzas of the Great Extended Hustlers, at 1800 feet ; 
 the New Chum Consolidated, at 1810; the Shenandoah, at 1900; 
 the Lazarus, at 2000; Lansell's " 222," at 2000; the New Chum 
 Railway, at 2025; and the North Old Chum, at 2290 feet. As I 
 have said, there are 1 8 shafts over 2000 feet in depth. They belong to 
 20 companies, there being two instances the two in Shenandoah and 
 the twin Lazarus companies where one main working-shaft is used 
 in common. Out of these 20 companies, 7 are upon the dividend- 
 list; or, to inquire further, 4 are working quartz which is highly 
 auriferous and 6 are breaking ore which is yielding profits, while of 
 the remaining ten, nine are in that process of prospecting and develop- 
 ment which here succeeds (though it ought to accompany) a period 
 of stoping, and one is idle. This is a record above the average of even 
 shallow mining. 
 
 The actual yield, during 1890, of the deepest-producing mines is 
 
78 
 
 THE BENDIGO GOLD-FIELD. 
 
 given as follows in the quarterly report of the Victorian Mining 
 Department : 
 
 NAME OF MINE. 
 
 Quantity 
 crushed. 
 
 Yield. 
 
 Average. 
 
 Depth 
 of 
 Slopes. 
 
 Depth 
 of 
 Shaft. 
 
 Oz. 
 
 Dwt. 
 
 Gr. 
 
 ;oz. 
 
 Dwt. 
 
 Gr. 
 
 Feet. 
 
 Feet. 
 
 Tons. 
 
 Gt. Extended Hustlers... 
 Lazarus Company 
 
 16,612 
 6,232 
 7,282 
 3,454 
 18,721 
 9,797 
 7,325 
 7,474 
 1,048 
 2,496 
 1,752 
 3,117 
 
 3,780 
 5,059 
 3,665 
 2,510 
 5,153 
 2,243 
 10,371 
 5,039 
 948 
 1,446 
 1,169 
 1,183 
 
 4 
 
 16 
 2 
 
 14 
 10 
 17 
 3 
 3 
 19 
 13 
 13 
 
 
 
 
 
 
 
 12 
 
 
 21 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 4 
 16 
 10 
 14 
 5 
 4 
 8 
 13 
 18 
 11 
 13 
 7 
 
 13 
 
 
 
 6 
 1 
 12 
 12 
 14 
 8 
 11 
 2 
 5 
 8 
 14 
 
 1,800 
 2,000 
 2,000 
 1,950 
 1,800 
 1,900 
 2,025 
 1,990 
 1,990 
 1,800 
 2,290 
 1,800 
 
 2,040 
 2,110 
 2,110 
 2,105 
 1,850 
 1,940 
 2,078 
 2,010 
 2,010 
 1,840 
 2,310 
 2,113 
 
 Jjazarus No 1 
 
 Lansell's "22" 
 
 New Chum Con 
 
 New Chum United 
 
 New C^um Railway 
 
 
 North Shenandoah 
 
 Shamrock 
 
 North Old Chum 
 
 
 
 Totals 
 
 85,310 
 
 42,571 
 
 5 
 
 9 
 
 
 
 
 23,345 
 1,945 
 
 24,516 
 2,043 
 
 Averages 
 
 
 9 
 
 23 
 
 
 
 
 
 
 
 Leaving on one side numerous small lots of ore, and taking into 
 account only the results obtained from 12 of the deepest mines which 
 were working regularly, it is found that during the year these dozen 
 claims yielded 85,310 tons of ore, giving 42,571 ounces or an aver- 
 age of 10 pennyweights per ton, the average depth at which the ore 
 was broken being 1945 feet. 
 
 All but one of these mines are on the dividend-list. We must 
 inquire further in order to arrive at a just appreciation of the signifi- 
 cance of this analysis. Of these 12 mines, 11 are paying dividends 
 on ores broken at an average depth of about 2000 feet. There are 
 a similar number, working at an equal average depth, which are not 
 at present making profits. It is most probable that, during an in- 
 terval of a year fully a third of the former will step into the ranks 
 of the latter; that is to say, they will cease to break highly aurifer- 
 ous quartz and become prospectors for a new run of ore-ground, 
 while, on the other hand, an approximately similar number will 
 replace them from the list of mines which at present are in process 
 
THE BENDIGO GOLD-FIELD. 79 
 
 of development. We see, then, that at the present time half of the 
 mines working at depths between 1800 and 2600 feet are profit-pay- 
 ing. The average yield of their ore is 10 dwt., while that of the 
 district as a whole is 9 dwt. 5 gr. per ton. The best returns at 
 present come from the New Chum Railway, which, at 2025 feet 
 depth, is breaking quartz averaging nearly J J ounces per ton. Dur- 
 ing the year this mine paid dividends amounting to 21,672 on a 
 paid-up capital of 28,589 and a nominal capital of 36,890. Its 
 total dividends to date have been 52,078. 
 
 During the second half-year the Shenandoah, working at 1990 
 feet depth, produced 4555 tons of quartz, yielding 3717 oz. 17 dwt., 
 or an average of 16 dwt. per ton. Dividends of 8400 were paid 
 during the 6 months, on a called-up capital of 12,800. Altogether 
 this company has returned 59,600 in dividends. 
 
 The Lazarus Company, working at 2000 feet, on 76-dwt. ore, paid 
 out during 1890 dividends of 15,750 on a paid-up capital of 63,- 
 187. The total dividends of this mine to date have been exactly the 
 full amount of its nominal capital, 67,500. 
 
 The results obtained in some cases appear to leave a very slight 
 margin of profit. The average of the Great Extended Hustlers, the 
 New Chum Tjnited, and the New Chum Consolidated mines is very 
 low. It speaks well for the size of the lodes and the handling of the 
 ore, that dividends are possible at a depth of nearly 2000 feet on 5- 
 dwt. mill-stuff. The New Chum Consolidated is an instance of very 
 successful gold-mining. The return of 5 dwt. 12 gr. shown in the 
 list given above is higher than the ordinary average of the minef 
 since richer quartz than usual was broken in the second half year. 
 For the year ending 30th June, 1890, 9586 tons were sent up from 
 the 1800-foot level, yielding. 1722 oz. 19 dwt. of gold at the mill 
 and 278 oz. 8 dwt. (from 106 loads) at the pyrites works. The total 
 value of the yield was 7943 5s. 9d. The average of the ore was 
 3 dwt. 14 gr. only, but this gave a profit of 1510 6s. 9c/., equiva- 
 lent to a shilling dividend on each of the 28,000 shares. The yield 
 was 16s. 9d. (say 4) per ton, and the cost 13s. 5d. (say $2.70) per 
 ton. Even on this low return the company, having a paid-up capi- 
 tal of only 18,200, was working at a profit of 11 per cent, per an- 
 num. The New Chum Consolidated has paid 132,300 on its 
 nominal capital of 42,000 and its oaid-up capital of 18/200. The 
 other mines will show scarcely less striking results so far as concerns 
 the ratio of money returned to that expended.* 
 
 * As stated in the first part of this paper, out of the 28 dividend-paying mines of 
 
80 THE BENDIGO GOLD-FIELD. 
 
 The favorable record of deep mining in this gold-field, as ont- 
 lined in the above paragraphs, has led many to quote the district in 
 proof of the richness of the deeper portions of quartz lodes. This 
 argument ignores the unique character of the geological structure of 
 the district. Bendigo does not furnish proof of the continuance of 
 pay-ore to great depths in ordinary veins. If we look upon each 
 saddle-formation as a distinct lode (which it no doubt is), we per- 
 ceive that the vertical extent of the auriferous quartz is very limited. 
 As a rule, in this district, a "reef" which can be worked to profit 
 in three levels or stoped in two lifts may be considered above the 
 average. The different saddles form distinct lode- formations, trav- 
 ersing beds of the country-rock which are different from those either 
 above or below. 
 
 PROSPECTING. 
 
 It is* the fact last mentioned which necessitates the most patient 
 prospecting. Systematic development is always one of the most 
 important features of mine-work. In such ore-deposits -as these it 
 is of paramount importance. Owing to lack of reserve-capital, and 
 the haste made to sink the shafts deeper, there has not been that 
 careful and patient prospecting, which the peculiar structure of the 
 district demands, of the ground rendered accessible by each level. 
 
 Several of the richest saddle-formations have passed longitudi- 
 nally through a succession of adjacent claims. Such was the main 
 Garden Gully saddle, and such is the formation now so successfully 
 worked from the New Chum Railway to the " 180" mine. As a 
 rule, however, the ore-shoots, particularly the richest, are small in 
 extent, and, unless the ground is carefully cut up by drifts and cross- 
 cuts, they are easily missed. Two instances will illustrate this. In 
 the Old Hustlers mine, after the workings had reached a depth of 
 over 1500 feet, there was accidentally found, last February, a good 
 body of auriferous quartz, between the 730- and 830-foot levels, in 
 ground which had been considered thoroughly tested. In the Her- 
 cules and Energetic mine there was found, in December, 1889, a 
 body of quartz 8 feet square, which gave 9000 worth of gold, 46 
 tons yielding at the rate of 46-J ounces per ton. This was exposed 
 in making a connection with a winzp, and was as unexpected as it 
 was valuable. 
 
 1890, I obtained the results given by 20, and found that all save four had more than 
 returned their paid-up capital. The average of the 20 showed an expenditure of 
 31,167 per mine on a nominal capital of 48,742 pe'r mine. 
 
THE BEOTIGO GOLD-FIELD. 81 
 
 At present, the work of development is confined almost entirely 
 to the three great " lines of reef," the New Chum, the Garden 
 Gully, and the Hustlers, and more particularly to the immediate 
 vicinity of the big mines. This is not surprising. New mines are 
 opened as continuations of already proved properties, and there is a 
 strong tendency to remain in the neighborhood of ground which is 
 known to have been rich. But at Sandhurst this has been overdone, 
 and the result is that the north and south extensions of the main 
 " lines of reef " have been but little tested, while similarly the inter- 
 mediate lodes or "side-lines" have been much neglected. Since it 
 has been demonstrated by the Geological Survey, as well as by actual 
 mining, that the gold-belt continues for several miles on either side 
 of the towns of Eaglehawk and Bendigo, it would be well to dis- 
 tribute upon shallow ground, which is as yet unworked, a little of 
 that energy and capital which is now expended on deep sinking ; for 
 here, as in most mining districts,* the first few hundred feet are gen- 
 erally richer than any succeeding horizon. 
 
 As to the exploration of the " side-lines " or quartz formations 
 which occur between the main anticlinal axes, attention has been 
 drawn to these portions of the district by the marked success of the 
 New Red, White, and Blue Consolidated, which is working a run 
 of rich spurs on the Sheepshead lode or reef, intermediate between 
 the Garden Gully and the New Chum. In this connection it is a 
 curious fact that, notwithstanding the system of government assist- 
 ance, no cross-cut has been driven between the main u lines of reef" 
 in that portion of the district (in the town itself) where they have 
 been proved to be richest. Such an exploration is recommended by 
 the structure of the country, the richness of this section of the gold- 
 field, and the experience of other mining districts. 
 
 OUTLOOK FOR THE FUTURE. 
 
 The prospect of future deep mining on this gold-field is most 
 encouraging. The depths yet reached are far within the capabilities 
 
 * There are exceptions, but they are not numerous. I recall the history of some 
 of the mines on the "Mother-lode" in Amador county, Cal., where no profitable 
 returns were obtained until several hundred feet had been sunk. As a rule, how- 
 ever, the increasing richness of mines with depth is a fal.lacy too often found among 
 the paragraphs of a mine-report. In most districts there are few gold-mines, the 
 first 50 to 200 feet of which did not exceed in richness any succeeding horizon. 
 
 6 
 
82 THE BENDIGO GOLD-FIELD. 
 
 of modern mining machinery.* There is no reason to expect any 
 increase of water ; on the contrary, the experience of deep mining 
 in other places points to a diminution in the quantity of water as 
 depth is gained. No chemical causes have been observed as active 
 in this district which would tend to make the underground temper- 
 ature increase other than with the usual increment of 1 for every 
 50 or 60 feet of additional depth. Moreover, there is every proba- 
 bility, from a geological standpoint, that the saddle-reef formations 
 will be repeated, as in the 2000 feet or more already pierced ; for the 
 only cause likely to bring them to an end, the granite contact, is at a 
 depth far beyond human reach. The cost of exploitation will in- 
 crease with depth, but, as the mines are comparatively dry and the 
 encasing rock does not become harder, it need not be expected that 
 this increase will be material between 200$ and 3000 feet.f Below 
 3000 feet, increased power and efficiency of the winding-engines, for 
 \yhich there is yet plenty of room at Sandhurst, will compensate for 
 the increasing distance from which the ore will be lifted. 
 
 At present, generally speaking, 5 dwt. of gold per ton will, with a 
 3-feet or 4- feet reef, pay the expenses of the mine and mill. The New 
 Chum Consolidated has shown how, at the end of the second thousand 
 feet from the surface, 3J-dwt. ore may be made to pay. The width 
 of the lode in the New Chum Railway, the Shenandoah, the New 
 Chum Consolidated, the New Chum United, etc., averages about 6 
 to 8 feet; and it is the width of the quartz in the reefs which will 
 determine the economical results of its extraction. In this respect 
 there is no reason to foresee a diminution. Nor is there any ap- 
 parent reason to expect a decline in the gold-contents of the quartz. 
 In most gold-mines the first 200 or 300 feet are richer than any suc- 
 ceeding horizon of similar thickness; but having once passed out of 
 the region of surface-waters there is nothing to cause one to expect a 
 marked change. Poor zones and rich ones will alternate as hereto- 
 
 * The shafts are invariably vertical, the winding being done by steam-power with 
 round wire-ropes and cages. Double-decked cages are not in use. Under the gov- 
 ernment regulations and the supervision of the mine-inspector, the winding-appa- 
 ratus is always in good order, and the safety-appliances are frequently and regularly 
 tested. 
 
 f The speed of sinking varies. The country traversed by the New Chum lode 
 is less hard than that of the Garden Gully ; hence, while at a depth of over 2000 
 feet in the " 180 " mine, the speed of sinking the last 200 feet averaged 20 feet per 
 fortnight (the distance from 2440 to 2640 feet being accomplished in exactly ten 
 fortnights) ; the average rate in the Victory and Pandora, on the Garden Gully 
 line, is 12o feet per fortnight. In both cases timbering, etc., is included. 
 
THE BENDIGO GOLD-FIELD. 83 
 
 fore ; but, owing to the folding of the country in which the reefs 
 occur and the recurrence of the beds, the mine-workings will, at 
 greater depths, pass through portions of country already met with 
 nearer the surface. The gold does not appear to have become more 
 refractory with increasing distance from daylight ; the percentage of 
 pyrites has varied but little, while the fineness of the gold has not 
 changed.* 
 
 It will be primarily a question of the economical handling of the 
 ore, and in this respect the underground exploitation is at present as 
 good as the treatment at the surface is bad. With mills of enlarged 
 capacity, properly equipped with modern improvements (particu- 
 larly with automatic feeders and with rock-breakers), the Bendigo 
 gold-field should long continue to be the home of successful gold 
 quartz-mining and the pioneer of deep sinking. 
 
 NOTE BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other errors, 
 or communications for publication as " Discussion/' or independent 
 papers on the same or a related subject, are earnestly invited. 
 
 * In the Lazarus, at 2000 feet, I saw white quartz containing beautiful coarse 
 gold in pieces weighing several pennyweights. The gold at the greatest depths 
 cached is still 22f to 23 carats or 945 to 960 fine. 
 
[TRANSACTIONS OF THE AMERICAN INSTITUTE OP MINING ENGINEERS.] 
 
 THE BENDIGO GOLD-FIELD (SECOND PAPER): ORE- 
 DEPOSITS OTHER THAN SADDLES. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Schuylkill Valley Meeting, Reading, October, 1892.) 
 
 THE earlier paper (Trans., xx., 463) describing this Victorian 
 mining district, to which the present is supplementary, was mainly 
 confined to the consideration of the "saddle-reefs," as scientifically 
 the most interesting and economically the most important of the 
 ore-deposits of Bendigo. Incidentally, however, references were 
 also made to other gold-bearing quartz-formations worked in the 
 district ; and of these a brief account will now be given. Among 
 them the most productive is that which is locally named a " make of 
 spurs" or "spur-formation," that is, a network of quartz-veins 
 bearing some resemblance to the type known as Stockwerk. 
 
 THE CATHEKINE REEF UXITED. 
 
 This mine, situated at Eaglehawk, is a representative of the class 
 characterized by this form of ore-deposit. The underground work- 
 ings disclose a strikingly regular succession of alternating slate and 
 sandstone beds with easterly dip. The different members of the 
 series are named according to their thickness, which in any one bed 
 varies between narrow limits only. Fig. 1 is a cross-section, illus- 
 trating the structure of that portion of the Lower Silurian country- 
 rock which contains most of the mine-workings. The scale of the 
 drawing is too small, and it would otherwise be confusing, to indi- 
 cate the quartz-spurs themselves; but it will be understood that cer- 
 tain members of this series of slates and sandstones are traversed by 
 comparatively small and generally irregular veins of quartz called 
 " spurs," and confined either to one bed or to a certain succession of 
 beds. 
 
 The " ore-shoots" of the mine are the "runs" or "makes" of 
 spurs, which in one plane (that of the strike of the enclosing rock) 
 pitch north 22 inches in 6 feet, and in the other plane ^that of its 
 dip) cross the bedding of the country nearly at right angles, thus 
 
 1 
 
2 THE BENDIGO GOLD-FIELD. 
 
 presenting a contrary or westward dip to the extent of the width of 
 the belt. This width, measured upon the westward dip, varies for 
 the "runs" in this mine from 150 to 200 feet. Along the strike 
 they have been followed north and south for several hundred feet, 
 but the extent of their development necessarily depends upon eco- 
 nomic considerations, the amount of gold they carry and the hard- 
 ness of the rock they traverse. In the Catherine Reef United, the 
 two shafts are 947 feet apart, and one run of spurs has been traced 
 throughout this distance and 300 feet beyond. Such a network may 
 have its regular course disturbed by faults, and is subject to the 
 irregularities of strike and dip which usually characterize such for- 
 mations. 
 
 In this mine the bed richest in spurs and most productive in gold 
 is the "forty-foot sandstone " (see Fig. 1), so called from its thick- 
 ness. It is overlain by the ten-foot slate, the two-foot sandstone 
 and the five-foot slate. The two-foot sandstone is so hard, and forms 
 so marked a feature of the underground workings, that the miners 
 have named it " The Devil's Back/' and by this term it is generally 
 known. Underneath and west of the forty-foot sandstone comes a 
 regular series, including, in the order named, the eighteen-foot slate, 
 the thirty-foot sandstone, the six-foot slate, the eighteen-foot sand- 
 stone and the thirty-five- foot slate. The wider beds of sandstone 
 are often subdivided by slate partings, as the thirty-foot slate, for in- 
 stance, is cut up by several thin seams of sandstone. The divisions 
 into slate and sandstone are frequently somewhat arbitrary, since 
 there are rocks of intermediate composition, sandy slate and slaty 
 sandstone, recognized by the miners as "bastard slate 7 ' and "bas- 
 tard sandstone." The main divisions into the "bars" or beds of 
 stated thickness are determined at the time of driving the cross-cuts, 
 when the drill decides the question of relative hardness and fracture. 
 
 The spurs worked in the forty-foot sandstone, in the stopes above 
 the 676-foot level, will serve as illustrations. Figs. 2 and 3 are re- 
 produced from the sketches made underground. In Fig. 2, A is the 
 bed of sandstone dipping east and penetrated by a series of quartz- 
 veins inclining flatly to the west. These do not penetrate the over- 
 lying slate B, but they are found in the underlying bed C, where their 
 position is almost invariably changed to a steeper angle. The frac- 
 tures filled with quartz have many of the features of joints, as shown 
 in Fig. 3, which illustrates the same bed of sandstone in another 
 part of the mine, where it is barren of quartz but fractured in lines 
 which are almost at right angles to the plane of bedding. 
 
THE BENDIGO GOLD-FIELD. 3 
 
 The width of a breast (4 feet) in the stopes ordinarily shows an 
 average of three spurs, the largest about 8 inches and the smallest 1 J 
 inches in thickness, giving an average width of 15 inches of quartz 
 in the 4 feet of sandstone rock broken for the mill. 
 
 In Fig. 4 a longitudinal section is presented, as seen in the north 
 stopes of the 676-foot level. It will be noted that the spurs pitch 
 to the north, their dip being (as we have seen) to the west. Lines of 
 cross-fracture or jointage are indicated. The upper spur A carries 
 an inclusion of country C. This is considered favorable to the 
 occurrence of gold, which, as in ordinary vein-mining, often " makes 
 at the point of a horse." The lower spur B shows two splices. 
 
 Fig 5 illustrates a behavior on the part of the spurs, which is 
 characteristic of them all over the gold-field. A quartz-seam, upon 
 leaving a bed of sandstone and entering one of slate, invariably turns 
 its dip in sympathy with the cleavage of the slate. Frequently a 
 big " blow " or irregular body of quartz is formed in the slate sepa- 
 rating two beds of sandstone. This is very marked in the case of the 
 ten-foot slate, as shown in Fig. 5, where S S are spurs, A is the forty- 
 foot sandstone, B the ten-foot slate, C the " Devil's Back," and D 
 the five-foot slate. 
 
 The " leaders," the position of which is marked on the general 
 cross-section (Fig. 1), form a marked feature, and are useful guides 
 in the underground workings. They are essentially thin seams of 
 quartz and clay, following the line of parting between certain mem- 
 bers of the series 'of slate and sandstone beds. The thickness of 
 quartz which they carry, though not uniform, is usually limited to 4 
 or 5 inches, and they are accompanied by a variable amount of graph- 
 itic clay, derived from the softer of the two bounding walls. It will 
 be noted that in every case save one the overlying bed is sandstone 
 and the underlying slate. In these cases the leaders carry a very clean 
 hanging-wall, often showing smooth, polished surfaces, sometimes 
 also marked by strice. The foot-wall country exhibits a variable 
 amount of distortion, and is frequently in a crushed condition for 2 
 or 3 feet below the black clay or mud of the leader into which it 
 gradually merges. 
 
 Following the stratification as they do, the leaders may be con- 
 sidered true bed- veins. There is abundant evidence that the plane 
 of parting which they follow has also been a plane of movement of 
 the enclosing rocks, and that the black clay which is one of their 
 chief characteristics is the result of the attrition which has crushed 
 the softer slate constituting one usually the lower of the two sur- 
 faces in contact. 
 
4 THE BBNDIGO GOLD-FIELD. 
 
 In the development of the mine, such a leader is often found to be 
 the apparent starting-line of a series of spurs. It is also found that 
 the latter are frequently faulted by the former. The second fact ex- 
 plains the first. Occasionally, the displacement is so small as to be 
 of no importance to the miner, though interesting to the geologist. 
 
 Fig. 6 illustrates "the leader/' so-called to distinguish it from 
 the " east," " west," and "black" leaders, shown in Fig. 1. The 
 sketch was made in a short cross-cut from the 676-foot level. The 
 leader D separates the forty-foot sandstone A from the eighteen- 
 foot slate B. It consists of a thin but regular vein of quartz E, 
 accompanied with black clay or fluccan, varying from one to three 
 inches in thickness. The spur S in the forty-foot sandstone is seen 
 to reappear in the eighteen-foot slate ; but in crossing the line of the 
 leader it has been dislocated and broken. The throw is two feet. 
 C C are fragments of quartz broken off the spur by the movement 
 along the plane of the leader. The greater resistance offered at this 
 particular point by the quartz of the spur has caused a local increase 
 of the thickness of crushed material ; and consequently there is a 
 width of 4 or 5 inches of black clay between the two faulted por- 
 tions of .the spur. 
 
 Fig. 7 shows the" black leader," so-called because in this instance 
 quartz is frequently absent, and entirely replaced by graphitic clay. 
 The unusual thickness of the latter is explained by the fact that the 
 overlying bed A, the eighteen-foot sandstone, has more than ordinary 
 hardness, while B, the underlying thirty-five foot slate is compara- 
 tively soft. The sandstone forms a straight, clean, polished hanging- 
 wall. The leader carries imbedded in the clay small pieces of 
 quartz, probably the shattered remnants of quartz-veins broken 
 through by the movements along the plane of the leader. The width 
 is about 4 inches. The underlying slate is much crushed and dis- 
 turbed near the leader and is full of distorted threads and irregular 
 pieces of quartz, which become regular spurs at no great distance 
 from the leader. 
 
 In Fig. 8 the " east leader " is illustrated. The sketch was made 
 in the stopes, called the "No. 13 backs," above the 870-foot level, 
 main shaft. This leader follows the line of parting b'etween the 
 thirty-foot sandstone and the six-foot slate. A and B indicate the 
 thirty-foot sandstone, of which the part B is beginning to be marked 
 by slaty cleavage. C and D are the six-foot slate which, near the 
 leader, is sandy. The country on the two sides of the parting has a 
 nearly equal hardness, which explains the fact that this leader is no- 
 
THE BENDIGO GOLD-FIELD. 
 
6 THE BENDIGO GOLD-FIELD. 
 
 tably narrow and is accompanied by an unusually small amount of 
 graphitic clay. The sketch shows a fault to have taken place. The 
 throw is about 12 inches. Between the upper and lower portions of the 
 spur S the leader L is accompanied by a small quartz seam T. Though 
 this is very small, the fact that the two larger portions of the spur 
 are connected points to the conclusion that the faulting of the frac- 
 ture in which the quartz of the spur was deposited took place before 
 the deposition of that quartz, which, following the upper portion of 
 S, was arrested by the leader or parting between the two beds B and 
 C ; that it followed the line of fault, namely the leader, as the seam 
 T, and then resumed its course along the lower portion of the faulted 
 fracture. The reason for the narrowing of the quartz deposited 
 along T was, that the fracture between the two beds was very nar- 
 row and straight, not affording such facilities for deposition as were 
 given by the more irregular, broken and more horizontal fractures 
 across and in the country-rock itself. 
 
 While minor faults are found along the leaders, the latter are 
 themselves dislocated by larger faults, coming in from the west. 
 Fig. 9 shows one of these, as seen in the north stopes of the 1140- 
 foot level. F is the line or wall of the fault. The throw is from A 
 to B, 12 feet. The structural effects of the fault upon the country 
 (and therefore upon those fractures in the country which after the 
 faulting became the depositories of quartz) are shown by the spurs 
 S S, which, though not broken, have here departed from their usual 
 west dip, and incline slightly east. At a short distance from the 
 fault they are seen to resume their normal position. The seam lining 
 the fault-fissure is formed of quartz of a different character from 
 that of the spurs themselves. Fig. 10 illustrates another similar 
 fault, this time in the stopes above the 1070-foot level, north of the 
 shaft. The throw is 15 feet. The spurs are, as in the previous case, 
 distorted in sympathy with the fault, the line of which, F F, is 
 accompanied by three or four inches of crushed material. 
 
 Lava dikes are not often seen in this mine ; but Fig. 11 illustrates 
 their characteristic features, due to their later origin, in this gold- 
 field. Here the lava dike T, seeking the lines of least resistance, 
 traverses a bed of sandstone until it meets with a fault, which it fol- 
 lows for a short distance before taking to a bedding plane, which it 
 in turn leaves to accompany a joint fracture before finally resuming 
 its course along the line of parting between two beds. 
 
 The modes of occurrence of the gold, as observed in this mine, 
 present many points of interest. Figs. 12 and 13 are longitudinal 
 
THE BENDIGO GOLD-FIELD. 
 
 UJ Q 
 
 UJ UJ 
 
 OJ _| 
 
 z: < 
 
 I- 
 
8 THE BENDIGO GOLD-FIELD. 
 
 and cross-sections of two spurs, A and C, as seen in the 1118-foot 
 stopes. At and near the point marked with a cross in Fig. 12 there 
 was found, on the day of ray first visit underground, a very rich 
 bunch of gold-quartz. The spur C, though particularly gold- 
 bearing at its intersection with the diagonal spur B, was, however, 
 also rich for many feet in length. The quartz was white, some- 
 what crushed and friable. The gold was coarse and could readily 
 be separated from the enclosing quartz by the point of a drill.* 
 This spot afforded a typical example of the generally coarse char- 
 acter and iregular distribution of the gold in spurs. 
 
 Fig. 13, a cross-section of the spurs A and B shown in Fig. 12, 
 illustrates the almost invariable rule that the quartz- veins traversing 
 the rocks of this district cut across the sandstone, and travel along 
 the cleavage lines of the slate. Fig. 14 shows other spurs traversing 
 the beds C, D and E, which follow the same rule. 
 
 The appearance of the quartz forming the ore of the Catherine 
 Reef United mine would be considered in most other districts unfa- 
 vorable to the presence of gold.f It is very white and often some- 
 what sugary. Again, a miner usually dislikes vugs or geodes in a 
 gold-quartz vein ; but here they are often accompanied by gold, fre- 
 quently pseudomorphic after mundic. "Black Jack " or zinc-blende, 
 arsenical iron pyrites and mundic, are the minerals accompanying 
 the gold. Of these the last is present in the largest proportion. It 
 is coarsely crystalline and appears to favor the smaller spurs, par- 
 ticularly in the parts nearest the enclosing sandstone. Galena is not 
 often seen, but is considered favorable to the presence of gold. The 
 gold is generally coarsej and of high caratage. It is often visible, 
 and invariably so in rich ores. Pieces weighing 7 dwt., 4 dwt., and 
 many of two and three dwt. have been taken out of one spur, at 
 depths exceeding 1000 feet from the surface. As a rule the gold is 
 less coarse and more evenly disseminated in spurs which traverse the 
 slate than in those found in the sandstone. It would be hazardous 
 
 * It is the custom of the mine manager, in making his daily rounds of the work- 
 ings, to remove and take with him the more tempting pieces of gold exposed in the 
 spurs; and at this place we spent an interesting half-hour in breaking away the 
 richest of the " stone," which showed gold in particles as large as peas. 
 
 f Miners elsewhere would characterize it as " wild," " rash," "bastard," or " bull 
 quartz." 
 
 As indicated by the retorts in the mill. For instance a test lot of ore (46 tons) 
 gave 42 ounces of amalgam from which, on retorting, 34 oz., 15 dwt. of gold were 
 obtained. 
 
THE BENDIGO GOLD-FIELD. 
 
10 THE BENDIGO GOLD-FIELD. 
 
 to say that the slate is more auriferous than the sandstone, though 
 the experience of the manager* points that way. 
 
 Notwithstanding the occurrence of rich specimens, and the gene- 
 ral coarseness and purity of the gold, this mine presents, from a 
 business standpoint, what is familiarly known as a " low-grade 
 proposition/' The character of the work done is indicated by the 
 following figures. During six months (1891) 11,080 tons were 
 mined and crushed, yielding 2583 oz., 12 dwt. of gold, an average 
 per ton of 4 dwt., 16 gr. (including 34 tons of pyrites yielding 66 
 oz., 5 dwt.). One dividend of sixpence per share on 67,600 shares, 
 was paid during that period. 
 
 THE NEW RED, WHITE AND BLUE CONSOLIDATED. 
 
 This mine,f situated at the other end of the Bendigo district, 
 affords another interesting example of a spur formation. Though a 
 much smaller mine than the Catherine Reef United, it is at present 
 one of the best producers^ upon the gold-field. 
 
 Work is confined to three levels, 660, 760 and 820 feet respec- 
 tively from the surface. The main stopes, where the best sections of 
 the ore-deposit are obtainable, are above the 760-foot level. That 
 portion of the country in which the spurs are found dips to the east. 
 The formation or " make of spurs " pitches south, the individual 
 spurs having a variable direction. So far, the opening up of the mine 
 has not led to the recognition of " leaders," such as those noted in the 
 Catherine Reef United ; but the country is traversed by "walls" 
 having smooth faces and accompanied by black clay, which also dip 
 eastward, cutting the bedding at a small angle. The wedges of rock 
 thus formed between the " walls " and the planes of bedding neces- 
 sitate extra care in timbering the mine. These "walls" have been 
 lines of movement; and frequently the extent of the faulting can 
 be determined. Like the " leaders " elsewhere, they are found to 
 separate barren from auriferous ground, and hence are accepted as 
 
 * Mr. Robert Coates, to whom I am indebted for courtesy and for valuable infor- 
 mation. 
 
 f The original claim received its name from its first operators, a company of sailors 
 who had deserted their ships in Port Philip Bay, and taken to mining. On gala 
 days they were in the habit of decorating the works with red, white and blue flags. 
 
 J For the quarter ending September 30, 1891, this mine produced 5174 tons, 
 yielding 2815 oz., 15 dwt., and averaging 10 dwt., 21 gr. per ton. During the same 
 period the fortnightly dividends amounted to 5625. 
 
 $ My notes are from visits made in September and October, 1890. I would ex- 
 press my thanks to Mr. Wm. Hicks, the manager, for his courtesy. 
 
THE BENDIGO GOLD-FIELD. 
 
 11 
 
 
12 THE BENDIGO GOLD-FIELD. 
 
 guides in the development of the auriferous portion of the " make of 
 spurs." 
 
 Lava dikes are often seen in the workings of this mine. One in 
 particular can be followed through the different levels and stopes, 
 and is of economic importance in that it is held to limit the " run of 
 spurs" in the ground above the 760-foot level, although, below that 
 level, it crosses the ore-channel. The penetration of the country-rock 
 by the dikes is the most recent occurrence in its structural history ; 
 and the supposition of their agency in enriching certain portions of 
 an ore-shoot or spur-formation is an error, based upon accidental co- 
 incidences; In the above case, for instance, the lava follows, for a 
 certain distance, one of the " walls," which it then leaves to take an 
 independent line across the country. While following the wall it 
 limits the gold-bearing ground. Previous faulting along the plane 
 of the wall may have brought highly auriferous rock opposite to that 
 which is barren : and where this result is observed in contact with 
 the later lava-dike, it is natural, but erroneous, to ascribe to the in- 
 fluence of the dike what is in fact the effect of an earlier displace- 
 ment and separation of two portions of an ore-shoot, along a plane 
 of movement with which the dike happens to coincide in its local 
 position. 
 
 The accompanying sketches will illustrate the different structures 
 seen underground in this mine. Fig. 15, is a sketch taken in the 
 stopes above the 760-foot level. The bedding is indicated by the 
 arrow. H H is called the hanging- wall of this part of the stoping- 
 ground, that is, it is accepted as the upper or eastern limit of the 
 auriferous formation. The rock on the upper side is hard sandstone. 
 The " wall " is smooth, shows a graphitic lining and carries a little 
 clay. It is a fault, but the amount of throw I could not determine 
 owing to the disordered structure of the country. A is sandstone, 
 threaded by quartz-veins. B is slaty sandstone, disordered and car- 
 ying veins of quartz C, parallel to the ba.ltlin^. D is soft, black, 
 broken-op rock, likewise carrying quartz E; the sandstone F also 
 showing twisted pieces of quartz, of short length. G is slate. T is 
 the lava dike, here two feet wide, black and homogeneous. It hugs 
 a "wall," nearly parallel to that which bounds the other side of the 
 formation. 
 
 Turning round and looking south, one sees the other end of the 
 stopes, as shown in Fig. 16. This is 40 feet from the point illus- 
 trated in Fig. lo. The beds A, B, F, G consist of sandstone, slaty 
 sandstone, sandstone and slate respectively, corresponding to the 
 
THE BENDIGO GOLD-FIELD. 
 
 13 
 
 
14 THE BENDIGO GOLD-FIELD. 
 
 opposite breast of the works. C is massive quartz, more white and 
 less auriferous than the narrow spurs E E, with their interlacing 
 quartz-veins. T is the dike. 
 
 Fig. 17 representing another part of the stopes above the 760-foot 
 level, shows how, in this mine, the quartz of the spurs follows some- 
 times the planes of bedding, sometimes cross-fractures. Close exami- 
 nation of the ground is usually required to distinguish the bedding. 
 The broken line on the parting between beds C and D in this figure 
 denotes that this boundary is very indistinct. This instance ex- 
 hibits again the behavior of the spurs, already repeatedly mentioned, 
 in u following " the slate, while cutting across the sandstone. (See, 
 for example, spur a, 6, c.) 
 
 Fig. 18 shows the structure of the breast of the 760-foot level. D 
 is slate which, near A, is black and broken. A is a quartz-vein 
 separated into two portions by the strip of black slate E, which last 
 carries a notable amount of pyrites. B is hard sandstone. G and 
 H are both slate, well marked by cleavage and appearing to be di- 
 vided portions of the same bed. C is a channel of soft country, 
 streaked with quartz and underlying the dike T; while F is a 
 vein of quartz, and O is sandstone. It will be noted that the coun- 
 try has been dislocated and that the lava follows the line of the fault- 
 fracture, which is also indicated by the soft broken country marked 
 C. Fig. 19 shows on a larger scale the cross-hatching of quartz 
 which occurs at the point marked K in Fig. 18. 
 
 Previous to the discovery of the gold-bearing character of this 
 spur-formation, the work of the mine was confined to what is known 
 as the " Sheepshead main reef," a large lode of massive quartz which 
 is cut by the 760-foot workings. As there exposed, it is from 12 to 
 14 feet wide, conformable with the bedding, and separated from the 
 spur-formation now worked by 30 feet of very hard sandstone. This 
 lode of quartz does not extend upward so far as the 660-foot, nor 
 down so far as the 820-foot level, but was worked along the strike 
 for 70 feet north and 169 feet south of the shaft. It is uniformly 
 poor. 
 
 The " run of spurs " is worked in this mine for a width of 20 to 
 25 feet. Its extent north and south is not yet known. The forma- 
 tion is subject to irregularities of several kinds ; but occasionally it 
 has a well-defined character, that of a series of quartz seams confined 
 to a certain narrow belt of country. The number and size of the 
 spurs is always varying. Sometimes one or two rich spurs pay for 
 the removal of a large width of poor rock ; sometimes the sandstone 
 
THE BEXDIGO GOLD-FIELD. 
 
 15 
 
 WH^r*.. 
 
 OJ 
 
 L 
 
16 THE BENDIGO GOLD-FIELD. 
 
 is so penetrated by a ramification of veins as to be substantially a 
 quartz-lode. Gold is often visible, especially in one or two particu- 
 lar spurs, comparatively narrow (say, 2 to 3 inches), which maintain 
 their individuality for a considerable distance 10 to 25 yards. The 
 ground is easily broken, but requires careful filling and timbering. 
 The ore as sent to the surface looks as if it comprised 75 per cent of 
 barren slate and sandstone. It will be understood that careful sort- 
 ing is out of the question, on account of the low grade of the quartz. 
 A representative fortnightly yield is 559 oz., 14 dwt. of gold from 
 641 tons.* 
 
 THE HERCULES AND ENERGETIC. 
 
 In my first paper on the Bendigo district, reference was made to 
 a quartz* formation known locally under the generic terra of "lode." 
 Such is that which has been developed in the Hercules and Ener- 
 getic mines at Long Gully. The "lode" is called the Victoria, 
 from the mine where it had its greatest development; but it is 
 really a portion of the main New Chum formation. It consists of 
 a channel of more or less shattered country-rock, threaded by quartz- 
 veins, some of which traverse it irregularly, while others are parallel 
 to the bounding walls. In dip and strike it is conformable with 
 the enclosing country. It may therefore be pronounced, in the first 
 place, a " bed-vein/' as distinguished from a "true fissure;" but it 
 may be also looked upon as a degenerated " leg" of a saddle-formation, 
 or again, as an exaggerated " leader." Since it evidently occupies a 
 line of movement, it can be called a fault or "slide," the filling of 
 which is occasionally auriferous. In this mine it is sometimes called 
 " the Victoria back," which means simply that the wall continues 
 when the accompanying quartzose and other material has " pinched 
 out." In any case, it illustrates very forcibly the difficulty of apply- 
 ing arbitrary definitions, and the absurdity of careless, dogmatic 
 labelling. 
 
 The " back," that is, the upper and best defined wall of the lode, 
 serves as the main guide in the development of the mine. Besides 
 the lode which " makes up against it," there are in its neighborhood 
 channels of country which carry spurs.f Sometimes both lode and 
 
 * Since the time of niy visit, the mine has continued to give excellent returns, 
 and is to-day the premier dividend-paying property in this gold-field. It was an 
 abandoned mine at one time, and owes its present position to the enterprise of Mr. 
 Geo. Lansell. 
 
 t I am reminded in this connection of a remark made by Mr. Northcote, the 
 manager of the 180 mine, to the effect that "backs " often formed the boundaries to 
 the gold-bearing portion of an ore-channel. 
 
THE BENDIGO GOLD-FIELD. 
 
 17 
 
 spurs are sufficiently gold-bearing to warrant exploitation, sometimes 
 the lode but not the spurs, or vice versa. 
 
 Nearly parallel to the " main back," there are other divisions in 
 the country, which are called " leaders." These are simply lines of 
 movement in sympathy with a main fault, and are marked by small 
 clay seams. They tend to meet the main lode on its dip ; and at the 
 junctions so formed, large bodies of ore have been found and profit- 
 
 - 20. 
 
 \ X T 
 
 HERCULES AND ENERGETIC 
 
 ably worked. Bodies of quartz as much as 40 feet wide have been 
 discovered under these conditions, bounded to the west by the 
 " back," but breaking into spurs towards the east. These spurs cut 
 through the so-called " leaders" and are found richest at the inter- 
 section. An example may be seen in Fig. 20, where A A indicates 
 the main back, and B is a large body of quartz breaking eastward 
 into the spurs S S, while C C are the " leaders." The spurs are 
 more flat, and there are more good spurs in the sandstone than in 
 
 2 
 
18 THE BENDIGO GOLD-FIELD. 
 
 the slate; although if a good (i.e., a highly gold-bearing) spur 
 traverses more than one bed of the country, it is not found notably 
 poorer in the slate. The gold is coarsest in the sandstone. It is 
 also noted that frequently the heaviest gold is on the foot-wall or 
 lower part of any given spur. 
 
 At the 600-foot level, the "Victoria lode" consists of a bed of 
 black slaty material, containing threads of quartz which carry both 
 coarse and fine gold. The manager informed me that the gold in the 
 slate was more flaky than that found in the quartz of the sandstone 
 which was, on the contrary, granular. In this part of the mine the 
 lode dips about 70 to the east, and strikes 20 west of north, which 
 is the strike of the New Chum Reef. 
 
 At the 1020-foot level, the lode has a remarkably clean, straight 
 hanging-wall. A sketch made in this level, facing south, is shown 
 in Fig. 21. A is the main wall; B is black, crushed slaty filling, 
 containing a large proportion of quartzose matter ; C is sandstone, 
 here notably nodular ; D is a thin slaty parting between the sand- 
 stone C and the bed of slate E, which contains a network, 9 feet 
 wide, of quartz-veins. The cleavage is indicated. 
 
 Forty feet below this level, or at 1060 feet below the surface, the 
 lode is faulted; and close to the point of dislocation there was found 
 a body of remarkably rich quartz, of which 46 tons gave an average 
 yield of 46 \ oz. per ton, producing over 2000 oz. of gold. The Vic- 
 torian Mining Department deputed Mr. E. J. Dunn, F. G. S.,* to 
 examine this occurrence; and his description appeared in the Quar- 
 terly Mining Report of March, 1890. My sketch, Fig. 22, differs 
 but little from his, except in minor details. S S marks the line of 
 the fault ; A is the lode. It will be noted that the throw of the 
 fault is equal to the width of the lode. The line of the fault is 
 marked by a wall, accompanied with black graphitic clay of vary- 
 ing width, while the country included within the limits of the lode 
 is shattered and traversed by a number of quartz- veins, of varying 
 size and direction. There is every gradation from clean black slate 
 to clean white quartz. The broken portions of included country 
 have become so interpenetrated by minute quartz- veins that it is im- 
 possible to say where the quartz begins and where the slate ends. 
 Locally it would be termed an extreme case of a " mullocky " reef. 
 The cleavage cuts through the slaty filling of the lode. 
 
 * This gentleman, one of the leading colonial geologists, has recently been en- 
 gaged in the preparation for the Victorian Mining Department, of a monograph 
 upon the Bendigo gold-field, which is to be published shortly. 
 
THE BENDIGO GOLD-FIELD. 
 
 19 
 
20 THE BENDIGO GOLD-FIELD. 
 
 At the point marked with a cross, in a space 8 feet square, there 
 was obtained 9000 worth of gold. When I saw it, the ore ex- 
 hibited a notable absence of the considerable percentage of pyrites, 
 usually present in the richer ore- bodies of the district; but I was in- 
 formed that at the time of working the " rich patch " there was 
 " plenty of mundic."* The gold was comparatively fine, the amal- 
 gam at the mill yielding one-third when retorted. The material a 
 few feet away from this particular rich spot was valueless, although, 
 as the manager said, somewhat similar in appearance to that which 
 had been so valuable. 
 
 The fault here observed has been encountered also at the 1120,- 
 1220- and 1320-foot levels, keeping a uniform direction, though the 
 width of broken country is subject to much variation, owing to the 
 varying hardness and structure of the beds traversed. Fig. 23 is a 
 sketch of the fault or " slide," as seen in the west drift of the 1220- 
 foot level. It has there a width of 4 feet, and consists of broken 
 country, mixed with quartz. The quartz A upon the under wall is 
 10 inches wide, but njn-auriferous. Stringers and irregular lumps 
 of quartz are scattered through the soft black crushed slate B. There 
 is a " dig " or mud-seam C upon the hanging-wall, only differing 
 from the broken slate in being more finely comminuted. The cleav 
 age is shown in the figure. 
 
 The sketches given indicate the great similarity between the struc- 
 ture of the fault and that of the lode. In fact, they both mark 
 lines of improvement ; but the latter follows the bedding, while the 
 former crosses it ; one is a cross-fissure while the other is a bed-vein. 
 Economically, they present the important difference that one is un- 
 doubtedly more auriferous than the other. 
 
 The discovery above mentioned, of the rich ore-body at the 1060- 
 foot level (which was almost accidental, having been made in con- 
 necting a winze with a " rise," in the course of ordinary working, 
 rather than of purposed exploration), shows how necessary it is to 
 prospect the mines thoroughly, and, wherever conditions known by 
 experience to be favorable are present, to cut up the ground carefully 
 and systematically. 
 
 THE CONFIDENCE EX-^ENDED. 
 This mine is full of geological puzzles, most of which are too 
 
 * These expressions are of course relative. At Bendigo, 2 per cent, of pyrites 
 is deemed a large amount. The concentrates obtained in the mills average 1 per 
 cent, of the ore. 
 
THE BENDIGO GOLD-FIELD. 
 
 21 
 
22 THE BENDIGO GOLD-FIELD. 
 
 complicated to be unravelled without detailed surveys.* In Figs. 
 24 and 25, I have given two sketches made underground at the 980- 
 foot level. In Fig. 24, A is sandstone ; B is slate, having a well- 
 defined cleavage; D is quartz; C is sandstone. At first sight, this 
 would be put down as an " inverted saddle," a syncline of quartz ; 
 but, on further study, the structure proves to be as shown in the 
 section, Fig. 25, where H, B, and K are beds of slate, characterized by 
 marked cleavage ; C, A, and L are sandstone, and the irregular de- 
 posit on the left of E E is quartz. There is no inverted saddle. On 
 the other hand, this spot illustrates an interesting feature of the sand- 
 stone beds of the district. I refer to the nodular structure men- 
 tioned already in one previous instance, which is often attended with 
 the deposition of quartz. It appears to me that A is a nodule, due 
 to the segregation of purer grains of sand from the general body of 
 the sandstone bed C. Movements of the country have caused frac- 
 turing around the wedge formed between the nodule A and the 
 bed of slate B; and in the fractures so formed the quartz has been 
 deposited. 
 
 The east wall, E E, is clean and straight. It can be followed, 
 unbroken, throughout the workings of the mine. The sandstone A 
 is very hard and fine-grained, carrying only a few fine threads of 
 quartz. The sandstone C is coarser grained and not so hard, and is 
 traversed, near the quartz bodies which it contains, by well-marked 
 lines of cleavage, which, while locally distorted, resume their nor- 
 mal direction a little lower down. The quartz is very heavily min- 
 eralized with mundic, and carries coarse gold. The formation pitches 
 north. 6f feet in 33 feet. 
 
 Fig. 26 was also sketched in this mine. It represents an elemen- 
 tary saddle formation, as seen in the 1250-foot level. B and D are 
 beds of sandstone, of somewhat similar composition, while A is finer 
 grained. The cleavage is indicated. In A there are structure -lines, 
 along which quartz seams have been formed. These lines, a, a, are 
 suggestive of bedding; they are, in fact, what may be termed "se- 
 cret-bedding," lines of lamination marking the original deposition 
 of the material forming the beds, and in harmony with the main 
 lines of parting or stratification. 
 
 Another rudimentary formation is seen in Fig. 32, from the 500- 
 foot level of the same mine. In this case we have the beginnings of 
 
 * My thanks are due for courtesy shown to rae by Mr. Abrahams, and afterwards 
 by Mr. Hall, managers of the mine. 
 
THE BENDIGO GOLD-FIELD. 
 
 23 
 
 O >- Z UJ 
 QC ^ uj UJ ( 
 
 " 
 
 UJ CM 
 
 O Q CO 
 
 Z U -o 
 
 UJ Q - 
 
 5o 
 
 CO 
 
 :-::-V\ .> \\ x 
 
 
 ^ 
 
 : :->mvs -\ \. 
 
 :-i^^s>"- 
 
 :-: : ---'---'V^ A ' -v 
 
 : ^*t^ 
 
 w> \ . / 
 
 OX I 
 
 -'y/:.-: 
 
 II' / '/ - 
 
 ^r '. 
 s 
 
24 THE BENDIGO GOLD-FIELD. 
 
 an " inverted saddle," or syncline of quartz. The sandstone A is 
 very hard, and is threaded with quartz. Along the curve of the 
 parting, between the two beds, there is a soft layer of black clay or 
 " dig." D D, is slate, C is quartz. 
 
 Fig. 29 is a somewhat similar exhibit, taken from the Whip and 
 Jersey mine, at the 700-foot level. Here, also, we have the sugges- 
 tion of an in verted -saddle formation. A is hard sandstone. C is 
 sandy slate. The dip is shown. There is crushed quartz and broken 
 country-rock underneath the saddle. 
 
 MISCELLANEOUS NOTES. 
 
 Several of the mines which were visited and examined by the 
 writer,* did not present peculiar features, though an occasional note 
 of value was afforded. Thus, at the Fortuna Hustlers, one of the 
 youngest of the Bendigo mines, and situated in the heart of the city, 
 was obtained the observation represented in Fig. 28. The sketch 
 represents the west leg of the saddle, which is part of the main 
 Hustler's formation. C is slaty sandstone, which forms the clean 
 hanging- wall of the reef; B is slate, A is quartz, D is the very hard 
 sandstone of the foot-wall. The cross-cut clearly shows the forma- 
 tion (see Fig. 27). The saddle pitches south ; the two legs, A and 
 C, are only 18 feet apart; and the bedding on the two sides is seen 
 to correspond. The cleavage is easterly above the west, and westerly 
 above the east leg. Center-country is hard sandstone. It is a sam- 
 ple type of the Bendigo saddle. The shaft was sunk, and the gold- 
 bearing reef was discovered, on inferences drawn from the informa- 
 tion given by a railway cutting. 
 
 Figs. 30 and 31 illustrate the behavior of quartz-veins which cut 
 across country. Fig. 30 is from the shaft of the Confidence Ex- 
 tended. A is sandstone, B is slate. The fracture, in which the 
 quartz was afterwards deposited, could take place as easily across the 
 even-grained and structureless sandstone as in any other direction, 
 but, when it entered the slate, the line of least resistance was found 
 to be with, rather than across, the cleavage. In Fig. 31, from the 
 Garden Gully United, the same behavior is shown, though in a 
 somewhat different way. 
 
 Figs. 33, 34, and 35, are three surface-sections, taken from a large 
 
 * The writer went through the underground workings of twenty-seven of the 
 Bendigo mines. 
 
THE BENDIGO GOLD-FIELD. 
 
 25 
 
26 THE BENDIGO GOLD-FIELD. 
 
 open cut behind the Victoria Quartz mine. ' The different beds of 
 slate and sandstone are indicated. In Fig. 33 it is seen how quartz 
 has been deposited along joint- fractures in the sandstone. Both 
 Figs. 33 and 34 illustrate the behavior characteristic of the small 
 quartz-veins of the district. In Fig. 35, A A is a quartz-vein hav- 
 ing a vein within itself, and presenting a sort of banded structure, 
 which indicates that it underwent fracturing after the deposition of 
 the first quartz. 
 
 CONCLUSION. 
 
 The above notes, scattered among the several mines of one mining 
 district, indicate the infinite variety of ore-deposition. Perplexing 
 as such differences of lode- formation may appear, and contradictory 
 as some of the modes of go Id -occurrence may seem, there is no doubt 
 that they can be shown to be the harmonious effects brought about 
 by the same set of causes, and due, in their variety, to the varying 
 structural conditions and relations of the beds of slate and sand- 
 stone in which they are found. 
 
f 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 THE ORIGIN OF THE GOLD-BEARING QUARTZ OF THE 
 BEND1GO REEFS, AUSTRALIA. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Chicago Meeting, being part of the International Engineering Congress, August, 1893.) 
 
 THE lode-formation of the Bendigo gold-field was described in a 
 former paper.* It presents a striking identity of arrangement with 
 the general geological structure of the region, which is one of com- 
 parative simplicity. The alternating beds of slate and sandstone 
 which constitute the prevailing country-rock have been extremely 
 contorted ; yet notwithstanding their highly developed cleavage it is 
 possible to discern in their structure the evidences of original sedi- 
 mentation. Along the crests of the waves which are the axes of 
 anticlinal folds occur bodies of gold-bearing quartz, of great econom- 
 ical importance, which the miners have appropriately termed "sad- 
 dles." They are more extensive in strike than in dip, are found to 
 occur in a recognized succession, and have been followed by a very 
 complete system of mine-workings reaching from the surface to more 
 than half a mile below. 
 
 I. THE KOCK-FORMATIONS. 
 
 At the commencement of our inquiry into the origin of this gold- 
 bearing quartz, it will be necessary to consider the relative ages of 
 the different formations of the region. Numerous* graptolites have 
 made it easy to label the slates and sandstones in which the reefs 
 occur as Lower Silurian. Any further subdivision, however, of 
 this great thickness of rocks has been rendered almost impossible by 
 reason of the striking lack of variety in the fossil remains, the gen- 
 eral confinement of their occurrence to the slates ; the marked 
 scarcity of conglomerates and breccias; and finally, the notable 
 similarity of texture and composition which characterizes the succes- 
 sive beds of slate and sandstone. 
 
 The enormous thickness of this series has been referred to. Dr. 
 A. R. C. Selwyn, at one time head of the geological survey of Vic- 
 
 * "The Bendigo Gold-Field," Trans, xx.,463. 
 1 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 toria,* estimated it at 35,000 feet. The same authority is in accord 
 with the present government geologist, R. A. F. Murray, in consid- 
 ering that a thickness of 7500 feet of superincumbent rock at one 
 time covered the beds which now form the surface. 
 
 The geological map of the colony f here reproduced (Fig. 1) indi- 
 
 Fig. I. 
 
 (j IMT.HOPE 
 
 
 "' l 
 
 
 i rmllry $ 1'uatcg t.nyre. A. I'. 
 
 ALE. 1^50 MILES 
 
 GRANITE 
 
 GEOLOGICAL SKETCH MAP 
 
 OF A PORTION OF 
 
 VICTORIA. 
 
 cates that the Silurian rocks of the BendigoJ gold-field are overlain 
 to the north by Tertiary shales, while south they abut against the 
 granite mass of Mount Alexander, which, in a horseshoe form, sepa- 
 rates this mining district from that of Castlemaine. 
 
 The contact between the two older formations is best seen in cer- 
 
 * Now director of the Geological Survey of Canada. 
 
 f Taken from "Geological and Physical Geography of Victoria," by R. A. F. 
 Murray. 
 
 I The old name " Sandhurst " appears on the map in place of " Bendigo." 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 3 
 
 tain road-cuttings at Big Hill, 7 miles from the town. The accom- 
 panying map* (Fig. 2) shows, on a scale larger than that of the 
 general map, the principal features of the surface geology of this 
 part of the district. It will be noticed that the crest of the ridge is 
 formed, not by the granite but by the Silurian rocks where hard- 
 ened by their contact with the granite. The railway passes through 
 the ridge ; but the tunnel indicated on the map is rendered useless 
 for the purpose of obtaining a geological section by reason of the 
 
 FIG. 2. 
 
 POST PLIOCENE 
 
 GEOLOGICAL MAP 
 
 BIQ HILL, BENDiQO. 
 
 brickwork which effectually hides the rock- structure. A short dis- 
 tance to the west, however, the main wagon-road, in crossing the 
 hill, affords several interesting sections. 
 
 The northern edge of the cutting shows the commencement of the 
 physical and chemical changes produced in the Silurian rocks by 
 contact-metamorphism.f The slate graduates into a crystalline 
 schist and the sandstone becomes a quartzite. More mica has been 
 
 * A reproduction of a small part of a general map of the gold-field, published by 
 the department of mines, Melbourne. 
 
 f Also termed by Daubre"e, " the metamorphism of juxtaposition," page 133, 
 Etudes Synthetiques de Geologic Experimentale. 
 
4 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 developed. At this point the structure of the country shows no 
 marked disturbance ; but in approaching the highest point of the 
 road, attention is drawn to a distortion of the bedding by the occur- 
 rence of a large black lava dike, which evidently follows a line of 
 fracture. 
 
 Further southward the rocks begin to exhibit more marked altera- 
 tion, being hardened, somewhat bleached, and very much jointed. 
 At the crest of the ridge the granite itself is first noticed. (See Fig. 
 3.) On the west the cutting gives a partial syncline, the members 
 of which show joints. Underneath, and upon a level with the road 
 itself, the first intrusions of granite are to be seen. Small veins of 
 it extend halfway up the height of the cutting. The rocks forming 
 the immediate foreground of the sketch are cut up by joints and 
 cross-joints. The bedding is indicated by the contour of the em- 
 bankment which forms the side of the road. 
 
 On the southern slope of the ridge the cleavage of the slates is 
 very marked, and the sandstones are traversed by several systems of 
 fracture, while both rocks have become hardened and more brittle. 
 The granite again appears in the form of small veins penetrating the 
 overlying rocks. (See Fig. 4.) The vein of granite, G, intrudes 
 among a series of thin beds which have been so altered that it is 
 difficult to recognize which of them were originally slate. Two 
 systems of joints, C C, are readily noted, more particularly in the 
 sandstones, A, A. A little further on, the gradually diminishing 
 sides of the cutting gave the section reproduced in Fig. 5, where G, 
 H and K are veins of granite (2, 2J and 15 inches wide respectively), 
 which have noticeably affected the sandstone bed A. The slates B, 
 B, are also baked, and their ordinary cleavage (60 to 65) is 
 largely obliterated by cross-fracturing. 
 
 The wagon road does not show the actual contact of the two forma- 
 tions ; but the railway, in approaching the tunnel from the south, 
 gave me the sketch seen in Fig. 6. Here the main mass of the 
 granite throws out small branches which intrude between the bed- 
 ding-planes of the slates and sandstones, penetrating them for a con- 
 siderable distance. Some of these veins, C C, are not more than a 
 couple of inches thick. The darker lines, B B, indicate segregrations 
 of ironstone. 
 
 Approaching the tunnel-entrance a crossing of two granite veins 
 is observed (Fig. 7). 
 
 To the facts above given, the following observations may be added. 
 At 500 yards from the contact the effects produced are only faintly 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 5 
 
 
 ~~ 
 
 ^^weaapr- . ..' - 
 
 iPSptP 
 
 '"-'.-' \~ ' ^--- "^"^v^/,^ 
 
 " :''^J ' .'j ~ ^ / if**^~*' l f *r*S < ''-r^~^ 
 
 Wii^^rn^ 
 
 m&im - 
 
6 ORIGIN OP GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 observable in the occurrence of joints recognized as not habitual ; at 
 300 yards the fracturing has become very marked and the rocks have 
 lost their usual cblor. Even in the immediate vicinity of the contact 
 the bedding of the Silurian rocks has not been notably disturbed. 
 The changes produced in the slates and sandstones consist in their 
 being somewhat bleached, considerably hardened, and very much 
 fractured. 
 
 The penetration of the sedimentary rocks for such a distance from 
 the contact by such small veins of granite, without however causing 
 any disturbance of the bedding, affords a study of peculiar interest. 
 To explain the behavior of the granite, it must be allowed to have 
 been in a mobile condition. Mobility suggests fluidity, and fluidity 
 in rocks is generally held to be the result of a molten state. An acid 
 rock could not, however, by reason of heat alone, be in a plastic, 
 much less a fluid state, except at an extremely high temperature. 
 That temperature has been approximately determined as being pro- 
 bably more than 2500 but less than 3000 F. Mallet's experi- 
 ments * on siliceous slags proved that their melting point was about 
 3000 F. Though we find that the general effects of heat upon the 
 slates and sandstones are indeed observable, yet the actual surfaces 
 in contact with the granite are not particularly affected ; and the 
 evidence as a whole strongly indicates that no such temperature as 
 that just mentioned could have existed at this point. 
 
 The volcanic phenomena of to-day furnish a clue to the problem 
 here suggested. The ejection of lava from volcanic vents is accom- 
 panied by enormous volumes, not of smoke but of steam. The 
 movement of a lava-flow down the mountain-side is marked by 
 those clouds of watery vapor whose after condensation precipitates 
 the heavy rains which are often more injurious to man than the 
 desolation caused by the lava itself. The subsequent examination 
 of the cold lava will show it to have a vesicular structure due to 
 the myriad bubbles of superheated steam which it contained at the 
 time of ejection. In this way, by the aid of the steam which forms 
 a large part of their bulk, acid lavas are often as mobile and ap- 
 parently as fluid as those which have a basic composition. More- 
 over, Daubree has proved that siliceous rocks which require a tem- 
 perature of 2500 to 3000 F. before they undergo true fusion will 
 yet become liquid at 800 F. if in the presence of superheated 
 steam. 
 
 * Also those of Sir Lowthian Bell. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 7 
 
 It is suggested, therefore, that the penetration of these slates and 
 sandstones for some distance from the contact by small veins of 
 granite was due to a condition of suspended solidification caused by 
 the presence in the igneous rock of imprisoned steam, taken up by 
 the intrusive mass of granite when at lower depths.* The granite, it 
 is true, does not now exhibit a vesicular structure such as would or- 
 dinarily characterize a rock whose mass has been interpenetrated by 
 steam ; but it must be remembered that it cooled under the pressure 
 of a great thickness of overlying formations and was extruded at so 
 early a period in geological time that any such structure would long 
 ago have been obliterated by those infinitely slow physical and 
 chemical changes which are forever bringing about the " decay and 
 repair " of rocks. 
 
 To the petrographer the granite presents no particular feature of 
 interest. It is of the normal type, consisting of mica, quartz and 
 orthoclastic feldspar. 
 
 It was extruded at a period previous to the Devonian, but later 
 than the Lower Silurian. The following facts warrant this state- 
 ment. In the sections afforded by the road-cutting and railway- 
 embankments at Big Hill, we have seen that it intrudes between and 
 across the bedding-planes of the slates and sandstones. It must 
 necessarily, therefore, be of later origin. Further, while the great 
 series of the Lower Silurian rocks has been much folded and con- 
 torted, yet this has not altogether obliterated the original lines of 
 their sedimentation, and we find that when the strike of the slates 
 and sandstones makes an acute angle with the locally irregular line 
 of the contact, their dip abuts against the granite. Viewed as a 
 whole, however, the general line of the contact is at right angles to 
 the strike, and, therefore, to the axes of the folds of the Silurian 
 rocks. This fact proves not only that the granite was extruded at a 
 period following the deposition of the Silurian sediments, but also 
 subsequently to that folding which is one of their most noteworthy 
 features. The stratigraphical position of the granite is further in- 
 dicated by the fact that elsewhere in the Colony its eroded edges are 
 overlain by rocks known to be Devonian, which are neither pene- 
 trated nor altered at the surface of contact. 
 
 Fig. 8 f represents a section at Mt. Hump Creek. 
 
 * Since the above was written I have read Rev. Osmond Fisher's " Physics of the 
 Earth's Crust," in which the author argues in favor of the existence beneath the 
 earth's crust of a liquid substratum of rock holding water-vapor in solution. 
 
 f From Geology and Physical Geography of Victoria, by R. A. F. Murray. 
 
8 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 Having determined the relative ages of the slates and sandstones 
 in which the quartz-reefs occur, and of the granite with which the 
 former come in contact, we have one other formation to consider. I 
 refer to the lava dikes, incidental references to which have been fre- 
 quently made in my previous papers on this subject. They form a 
 marked and instructive feature of the Bendigo mine-workings. A few 
 additional sketches will serve to illustrate further the characteristic 
 behavior of these " lava-streaks/ 7 as the miners call them. This is 
 
 FIG. 8. 
 
 A. SILURIAN B. OrmrNJTE C. DEVONIAN 
 
 well shown in the cross-section of the deep levels of the 1 80 mine. 
 (Fig. 9.) The course of the dike, whose width averages about 9 
 inches, can be readily followed as it cuts through the successive sad- 
 dle-formations. In Fig. 10 a dike (in another mine) is seen to tra- 
 verse a sandstone, cutting through several small quartz-veins, until 
 it reaches a bedding-plane, which it then follows. In Fig. 11 an- 
 other lava-streak, following the structural lines of the country-rock, 
 becomes " pinched out " in the plane of the section along which the 
 sketch is taken. Doubtless it found an easier passage elsewhere. In 
 Fig. 12 a larger dike, 14 inches wide, exhibits centers of decompo- 
 sition marked by concentric formations of white zeolites. There is 
 a dark band of less altered lava following the center of the dike. In 
 Fig. 13 a lava-streak separates into two small branches before finally 
 dying out. 
 
 It requires but little observation underground to determine the 
 recent origin of these dikes, which evidently followed a passage along 
 those lines in the country-rock offering the least resistance. 
 
 The lava is of Tertiary age, either Pliocene or post-Pliocene. It 
 is identical in lithological character with the basalt, successive sheets 
 of which, in a manner much resembling that to be observed in Cali- 
 fornia, overlie the Miocene and Early Pliocene gravel of the " deep 
 leads" of the alluvial mines of Victoria. The gold-field of Ben- 
 digo was probably also, at one time, covered by the lava extruded 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 from the dikes ; and while all vestiges of such an outflow have since 
 been removed by erosion, yet by a comparison of its structure, com- 
 position and behavior it is easy to see the similarity existing between 
 the rock which forms the " lava-streaks " of the deep workings of 
 
 I 
 
 I 
 
 the mines and that of the basaltic plateaux overlying the rich allu- 
 vium of the neighboring districts of Clunes and Heathcote, and the 
 more distant ones of Ballarat and Ararat. 
 
 It is not easy to determine accurately such a rock as the Bendigo 
 
10 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 lava. Igneous rocks in the vicinity of ore-deposits are almost in- 
 variably much altered, and therefore very difficult of examination 
 under the microscope. In the case of a basic rock, such as the one 
 under consideration, these difficulties are very much increased. 
 Upon examining a fair sample of the lava, taken from 2000 feet 
 below the surface, Prof. Judd, F.R.S., at the Royal School of Mines, 
 London, decided that, while now much altered, it was originally 
 basaltic in character and contained free crystals of olivine of con- 
 siderable size. The augite and magnetite are abundant and well 
 preserved, but the alu mi no-alkaline constituent of the rock has 
 almost disappeared. Leucite, nephelite, or even melilite may have 
 been present. The Germans would call such a rock "melaphyr," a 
 term which Dana,* however, highly disapproves. 
 
 In the mines the lava is generally far advanced in decomposition. 
 The olivine becomes converted into serpentine. The vesicles, often 
 arranged so as to indicate that the mass has flowed, are filled with 
 zeolites. At the surface, or within the domain of surface-waters, 
 this alteration has of course progressed even further, and only white 
 soapy clays remain to contrast with the black, compact, and homo- 
 geneous rock of the deep levels. 
 
 One feature of the behavior of these dikes has peculiar interest, 
 namely, their penetration through such an enormous thickness of 
 overlying rock. In the 180 mine I have traced from the surface to 
 a depth of over 2600 feet a dike only 9 inches wide. It is fair to 
 assume that the dike must have found its way for a distance many 
 times exceeding that for which it can be actually observed, for allow- 
 ance must be made for the portions eroded since the Tertiary 
 period, and also for that much greater unknown depth from which 
 the lava came. 
 
 The question arises, did the lava effect its passage slowly or was it 
 shot upward through its entire length and height in one instanta- 
 neous operation ? The latter explanation requires the formation of 
 a continuous fissure, itself unwarranted by the facts in this case, and 
 the conception of its instantaneous filling with lava along its entire 
 extent further presupposes that the material of the dikes remained 
 molten during the brief time of such a performance. Again, the 
 force which was able to shoot the lava upward through the tortuous 
 fractures, penetrating many thousands of feet of overlying rock, 
 would also cause it, when it reached the surface, to be ejected with 
 great violence and to a great height into the air. 
 
 * Manual of Mineralogy and Petrography, p. 485. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 11 
 
 Such an explanation is in accord with the catastrophic theories of 
 the past, but it is opposed by the modern study of volcanic action, 
 and does not harmonize with the facts as observed in the mines of 
 Bendigo. 
 
 The accurate observation of volcanic phenomena by Scrope and 
 Judd* has shown that the molten material issuing from the vent of 
 a volcano usually wells up slowly. The violent paroxysmic out- 
 bursts which do occasionally take place are essentially surface-occur- 
 rences, and are due to a sudden relief from pressure obtained by the 
 escape of accumulated superheated steam. 
 
 The course of the dikes and the effect of the lava upon the rock- 
 surfaces in contact must be now considered. Nothing in their mode 
 of occurrence is more remarkable than their tortuous and very irreg- 
 ular passage through the overlying rocks. They do not fill a clean- 
 cut, continuous fissure; they rarely preserve a straight line for any 
 great distance, but follow bedding-plane, joint and cross-fracture, as 
 each in turn presents itself. Where their line of passage takes them 
 across the quartz-reefs, the crossing is generally effected near the 
 apex of the saddle. The conclusion arrived at is, therefore, that the 
 penetration of the basalt through the slates and sandstones was not 
 the work of a few seconds, during which it was shot upward instan- 
 taneously through its entire height and length, but rather that it 
 required a long time, and took place during a period when the Silu- 
 rian rocks were subject to a tangential strain which caused their 
 fracturing and thereby, little by little, offered a passage to the basalt, 
 which being at the time under pressure, was seeking its way upward. 
 
 The effects produced upon the Silurian rocks, through which at 
 Bendigo the basalt penetrates, and upon the granite and gravel, upon 
 which in the neighboring districts it lies, are in each instance so 
 slight as to be barely observable. The feeble changes produced 
 upon the rock-surfaces in contact suggest themselves as due rather 
 to the action of water than to the effects of heat. 
 
 It is, indeed, true that rocks having the composition of these ba- 
 salts are fluid at a temperature low in comparison with that required 
 to melt an acid lava; but observation of the behavior of the dikes, 
 and of the effects produced upon the beds through which they pass, 
 impresses one with the conviction that the temperature of the mate- 
 rial filling them did not reach that which even the more basic of basalts 
 require for their fusion. The conclusion forces itself upon us that 
 
 * As described by the former in his book entitled Volcanos, and by the latter in 
 his Volcanoes. 
 
12 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO KEEFS. 
 
 the basalt of the " lava-streaks" did not owe its mobility to a molten 
 condition arising from intense heat. The government geologist, 
 Mr. R. A. F. Murray, states the belief that the dikes were "in great 
 measure the product of hydro-thermal action."* This is my view 
 also, which, more definitely expressed, is as follows : The material 
 of the dikes, when forcing its passage through the Silurian rocks, 
 was more in the condition of a boiling mud than what we ordinarily 
 imagine as the state of a liquid basalt ; its mobility was due not so 
 much to the fact that it was basic in chemical composition, and there- 
 fore more readily fused, but because of the superheated steam of 
 which it was full. Such imprisoned steam was superheated because 
 originating at a great depth. It has been found that within the very 
 restricted limits of human observation heat increases with depth. 
 As we sink through the earth's crust the average increment of heat 
 is at the rate of 1 F. per 47 J feet of descent, f Water cannot re- 
 main a liquid, in spite of increasing pressure, at a temperature above 
 that of its critical point. This was first determined by Caigniard 
 de la Tour to be 773 F. More recently, however, Battelli proved^ 
 that it was 364 C., equivalent to 687 F. Such a temperature, 
 taking the mean surface temperature to be 50 F., would be reached 
 at a depth of about 30,000 feet. In areas under disturbance and in 
 volcanic regions local conditions would tend to raise the temperature 
 and consequently to diminish the depth required to reach the horizon 
 where water can no longer remain liquid. A depth of less than 
 25,000 feet might then suffice. In the gold-field of Bendigo we have 
 to deal with a series of rocks over 35,000 feet thick. The basalt of 
 the dikes has come up through that thickness, and consequently 
 must have had its origin at a depth greater than that required to 
 reach the temperature of the critical point of water. Such water as 
 it contained must have existed, therefore, as water-vapor, which, as it 
 approaches the surface, we may call superheated steam. This steam 
 was in a state of compression, seeking to be relieved of its load, and 
 striving to go where only that load could be lightened, that is, up- 
 ward. The expansive force of such imprisoned steam rendered it a 
 
 * Op. cit., p. 137. 
 
 f Sir William Thompson (Lord Kelvin) estimated it at 1 per 51 feet. Prof. 
 Prestwich collected 530 observations made in 248 localities, and selecting those 
 only in which the necessary precautions had been taken, found the average to be 
 as above stated, 1 per 47 feet. 
 
 J At Turin, in 1890. Strauss gives the critical point as 370 C. and A. Najedin 
 as 358 C. This information I owe to Prof. Hallock and to Mr. Carl Barus. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 13 
 
 powerful agent in assisting the basalt to force its slow way through 
 the crevices and fractures of the overlying rocks until relief was 
 obtained at the surface. The lava would have lost some of its 
 heat and moisture by contact with the rock-faces along which it 
 passed, but having a temperature much above the lowest tempera- 
 ture of hydro-thermal fusion, it could lose much heat without solidi- 
 fication, and was therefore enabled to arrive at the surface where it 
 probably welled forth water, steam and mud, overspreading the older 
 rocks and ft the later gravel with one of those sheets of basalt which 
 form so marked a feature of the surface geology of the Colony of 
 Victoria. 
 
 The Silurian rocks form the Ultima Thule of all research into 
 the geological history of the region. Of the rock- masses by the 
 disintegration of which they were formed, no vestige remains. Their 
 uniformity of structure and composition, their thin bedding and 
 general regularity, their wide extent and great thickness, all prove 
 that they were the sediments deposited during enormous periods of 
 time from a comparatively shallow ocean. The frequent ripple- 
 marks now observed at a depth of many hundred feet below the 
 surface tell of estuarine seas and shallow reaches of water. The 
 absence of any large bodies of conglomerate and breccia indicates a 
 continuity of uniform conditions. 
 
 If the members of this great series of beds were deposited in 
 water of a generally uniform depth then it follows that the bed of 
 the Silurian ocean must have undergone a subsidence which kept 
 pace with the rate of sedimentation. The subsidence occurred along 
 a certain line of weakness in the earth's crust, which later became 
 the longer axis of a trough-like depression. The gradual deepening 
 of that depression corresponded with the slow rate at which it was 
 being filled. 
 
 As each layer of material became covered by another it began to 
 undergo a change; as the superincumbent mass became thicker and 
 heavier, the thin slime and the fine sand were consolidated by pres- 
 sure and commenced to take to themselves the form and structure of 
 the rocks which we term slate and sandstone. 
 
 When the area of depression had been loaded with a thickness of 
 seven miles of sediment, subsidence ceased and elevation began. 
 The existence of so great an accumulation of material determined 
 the choice of this part of the earth's crust as the place of an eleva- 
 tory movement. The lowermost layers of sediment were subject to 
 an enormous pressure whose effect was to cause condensation fol- 
 
14 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 lowed by contraction. This was the local cause which started the 
 action of the tangential strains due to the general compression of 
 the earth's crust. This compressive strain brought about the fold- 
 ing of the Silurian sediments, it caused them to be gradually ele- 
 vated and compelled the sea- waters covering them to recede slowly. 
 Their upper portions became dry land, and erosion at once com- 
 menced. 
 
 The forces still at work continued to exert a lateral compression 
 upon the sediments which now had become rock-masses. The effects 
 are seen in their highly developed cleavage and in the flexures and 
 undulations which are to-day their most marked feature. Their cor- 
 rugation made them stronger but less pliant. 
 
 Though bent and folded, the Silurian beds were not at this time 
 broken by extensive fissures. This was prevented by their great 
 thickness and by their comparative flexibility. That flexibility was 
 due in the first place to the water which they still held over from 
 the period of their sedimentation, and secondly to their fine grain 
 and thin bedding. 
 
 The neighboring rock-masses, forming the rim of the original 
 area of depression, were, however, unprotected by any such depth 
 of overlying, deposits; they were older and more rigid; and they 
 became consequently broken by fractures and fissures through which 
 volcanic agencies found a vent. It was then that the plutonic gran- 
 ite, perhaps, absorbing into its mass the lowermost portions of the 
 Silurian beds,* welled up toward the surface, giving out its heat as it 
 advanced. The granite as it was extruded must have exerted a 
 certain pressure against the slates and sandstones. It may have 
 been the agent which caused those minor transverse undulations 
 whose axes. are at right angles to the main ore-bearing anticlinal 
 axes of the Bendigo gold-field. 
 
 A period of comparative quiet followed. The Silurian rocks un- 
 
 * At Mt. Tarrangower there is an inlier of sandstone which suggests this. For 
 the following particulars I am indebted to Prof. Ulrich, of New Zealand : " The 
 Silurian inlier lies about 16 chains away from the Granite-Silurian boundary, form- 
 ing a small hillock about one acre in extent. It consists of a nearly black, dense, 
 metamorphic sandstone, and its boundary with the granite can, in several places 
 round its circumference, plainly be seen, but there is no change in the rock other 
 than that feldspar particles make their appearance near the boundary. However, 
 in a water-course which cuts across the contact the dark Silurian rock can in one 
 place be seen to run down into the granite; and there it becomes gradually quite 
 light-colored, i e., strongly feldspathic and also micaceous ; in fact, so altered that 
 any geologist seeing a hand-specimen of it would no doubt call it a fine-grained 
 granite." 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 15 
 
 derwent denudation ; their upper portions were disintegrated ; from 
 their debris other formations were built up, to be in turn eroded and 
 washed into the waters of the ocean. While the upper earth was 
 undergoing change, the under world was also the scene of silent 
 chemical and physical processes, removing matter here and laying it 
 down there, destroying and upbuilding, ever shifting their centers 
 of activity but never at rest. In the latter part of the Tertiary 
 period the basaltic lava found its passage through the fractures 
 traversing the Silurian rocks and covered the golden alluvium 
 lying upon their eroded edges. 
 
 II. THE AURIFEROUS QUARTZ. 
 
 The origin of the deposits of gold-bearing quartz, belongs to no 
 particular period. The agencies which brought the ore of the reefs 
 to its present position began to operate when first the sediments of 
 the Silurian seas were laid down, and have continued until now. 
 
 In the reefs of Bendigo the two most important substances are, 
 the metal, gold, and the matrix quartz. The other mineral con- 
 stituents found in association with these two are relatively unim- 
 portant. Their origin is a matter of much interest but it can be 
 discussed apart. 
 
 1. The Quartz. 
 
 The Silurian sediments contained a large proportion of sand, and 
 the resulting rocks are very siliceous. Silica occurs in the rocks 
 partly in a free state, as quartz, but a proportionally larger amount 
 is found combined as a silicate. Free quartz is soluble in heated 
 waters. The quartz combined in the more complex form of silicates 
 has been demonstrated by Daubree and others to be readily dis- 
 solved in hot water, more particularly superheated steam. 
 
 The formation of the quartz lodes has taken place in two stages, 
 namely, leaching followed by precipitation. In both operations 
 water was a necessary factor. It is the all-powerful disintegrating 
 and transporting agent of the land-surface, where its chemical ac- 
 tivity is intensified by the presence of dissolved carbonic acid; it is 
 also, though in a different way, no less efficient underground where 
 by reason of the prevalence of a higher temperature it becomes more 
 energetic both physically as a force and chemically as a reagent ; and 
 finally it is increasingly powerful at great depths where even the 
 tremendous pressure of superincumbent rock-masses will not prevent 
 it from being transformed into steam and developing a chemical 
 activity to which the mineral constituents of the rocks can offer but 
 
16 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 feeble resistance. It was the agent which, from a state of general 
 distribution, collected the quartz and brought it into the fractures 
 and fissures, crevices and cavities where the miner now finds it. 
 
 All rocks, though compressed and dried as they appear, contain 
 moisture.* All rocks are pervious to waterf to a varying extent by 
 reason of capillary action, and all rock-masses are permeable because 
 of the fractures and joints which traverse them. It has been shown 
 by Daubree, Bischof and others, that only a very small quantity of 
 water such as we find the rocks actually to contain is required to 
 produce the most pronounced changes in their chemical constitu- 
 tion, particularly when aided by pressure, accompanied by high 
 temperature. 
 
 The heat, in most instances accompanied by pressure, required to 
 make the water in the rocks intensely active, was afforded at various 
 times and for long periods. At the earliest stage of their history 
 they were subjected to high temperature. From the moment that 
 one layer of sediment was deposited on the ocean bed and became 
 covered by another it began to acquire a more elevated temperature 
 in consequence of its increased distance from the surface of radiation. J 
 As the thickness of the sediments kept pace with the sinking of the 
 bottom of the depression in which they were laid, the successive 
 beds acquired a temperature proportioned to their depth. The 
 lowermost members attained a distance of over 35,000 feet from the 
 surface. Though the increment of temperature be not constant with 
 increasing depth, yet the heat which obtained at a horizon seven 
 miles from daylight must have been extremely high.|| 
 
 The great thickness to which they attained caused an enormous 
 pressure to be exerted by the upper upon the lower members of the 
 series. Pressure does not develop heat unless motion also occurs. 
 When,' however, at the close of the period of their deposition certain 
 elevatory movements took place, their great thickness must have 
 helped to develop an energy which became converted into an exceed- 
 
 * The French call it eau de constitution. They also have a term eau de carriere, 
 which is the equivalent of our "quarry-water." 
 
 f The amount of water in the rocks and their porosity has been measured by 
 Sterry Hunt, Prestwich, Delesse, and others. See Chemical and Geological Essays 
 by the first and Geology, Chemical, Physical and Stratigraphical, by the second. 
 
 J An observation due to Babbage, and quoted by Daubree. 
 
 \ See Kev. Osmond Fisher's Physics of the Earth's Crust, 1889, chap. i. 
 
 || Le Conte, Elements of Geology, p. 93, says, " the lower portion of sediments 10,000 
 feet thick would be raised to a temperature of about 260, and of 40,000 feet thick 
 to that of 860." In the instance under discussion the eroded portions of the Silu- 
 rian sediments are estimated to have been 7500 feet thick, and their total original 
 thickness to have been 35,000 feet. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 17 
 
 ing heat. This period of elevation and corrugation was long; and 
 during its prevalence the slates and sandstones must have been sub- 
 ject to the full play of those slow chemical and physical forces which, 
 though less striking than violent volcanic outbursts and sudden 
 earth-movements, are yet the most powerful of the agencies which 
 modify the rocks. 
 
 Afterwards, when the granite was extruded, further heat was 
 diffused through the adjoining slates and sandstones. In the long 
 interval which separated the time of the extrusion of the granite 
 from that which marked the ejection of the basalt, the Silurian rocks 
 were subjected to slow movements of elevation and depression which, 
 while not so energetic as those which took place at the beginning of 
 their life-history, were yet sufficient to develop a rise of temperature. 
 In later times, the period during which the lava penetrated the older 
 rocks must have been marked by an increase of their heat. Though 
 the extrusion of both granite and basalt have left more striking evi- 
 dence of their occurrence than the slower movements referred to, 
 which took place at other periods, yet the heat they afforded was not 
 so widely diffused, and the effects produced were comparatively local. 
 The heat given out by both granite and basalt was however sub- 
 sequently widely distributed. 
 
 This distribution was effected through their contact with under- 
 ground waters which, becoming converted into steam, transferred 
 some of their heat to other circulating waters, and these in turn in- 
 jected their heat and steam through the pores and crevices of the 
 slates and sandstones. 
 
 The hot water and superheated steam * thus produced during 
 long continuing periods were the restless agents in leaching the rocks, 
 in dissolving out the silica from its state of combination and in after- 
 wards transferring it to underground currents which bore it away 
 until changed conditions compelled them to deliver it up by preci- 
 pitation as quartz. 
 
 Thus, in this and other ways, the quartz became separated out 
 through the pores of the rocks by a kind of sweating process,f to 
 be segregated along the joints and fractures traversing them. 
 
 * One feels inclined to speak of "superheated" water, but there is no such thing. 
 Superheated water, without reference to pressure, is steam. Geikie, though his 
 writing is generally a model of accurate expression, slips into the use of this term 
 on page 284, Text-book of Geology. 
 
 f Or, as Daubree puts it : " Le quartz a e"te fourni aux veines par une sorte 
 d'exsudation de la roche encaissante." 
 
 2 
 
18 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 The experiments of Daubree proved the action of superheated 
 steam in dissolving the silicates and the subsequent precipitation, 
 upon the lowering of the temperature, of crystalline quartz of a 
 character similar to that found in association with the gold and other 
 metals of ore-deposits. 
 
 The changed conditions compelling precipitation were very vari- 
 ous in kind and due partly to physical, partly to direct chemical 
 causes. In traversing the minute underground passages of the rocks, 
 the hot solutions would meet with portions of loose or crushed rock, 
 giving larger space, increased surface, and diminished pressure. 
 This would favor precipitation. The workings of mines often afford 
 illustrations of ore-deposits which owed their existence to such con- 
 ditions. Similarly hot waters meeting and mingling with colder 
 currents or passing between comparatively cool rock-surfaces would 
 have their solvent power diminished, leading directly to the depo- 
 sition of the material in solution. The hot springs of the present 
 day in many parts of the world give us familiar examples of the 
 precipitation of silica resulting from the lowering of the tempera- 
 ture of the issuing waters. A third cause may be quoted. The re- 
 ducing agency of organic and other matter is able to precipitate 
 silica from its state of solution as a silicate. Of this, silicified wood 
 is a familiar illustration. 
 
 The seas, the rivers, the thermal springs, and the underground 
 waters of to-day carry notable quantities of silica in solution. Forch- 
 ammer found sea-water to contain silica, and in certain samples he 
 determined the quantity to be as much as 3 parts in 1,000,000 parts 
 of water. A cubic mile of the ocean would, at this rate, contain 
 13,500 tons of silica. Deville showed that the river Loire, at Or- 
 leans, contained in 100,000 parts 13.46 of solid matter, of which 30 
 per cent, was silica. The geysers of the Yellowstone Park, those of 
 California, Iceland, and the north island of New Zealand, all de- 
 posit silica from the waters ejected by them. Steamboat Springs, in 
 Nevada, and Sulphur Bank, in California, may also be instanced. 
 The occurrence in New Mexico and Arizona of extensive areas which 
 have undergone submergence, and whose forests have become pet- 
 rified by the action of percolating siliceous solutions, affords a 
 striking instance of the transference of silica by underground waters 
 and its precipitation under favorable conditions. That the waters of 
 mines contain silica in solution has been proved by the silicificatiou* 
 
 * This, as pointed out to me by Prof. Le Conte, is a double process, consisting of 
 the filling of the interstices by the precipitation of silica and the actual replacement 
 of the woody fiber itself. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 19 
 
 of drift-wood, beautiful specimens of which have been found in tho 
 auriferous gravels of the " deep leads " of California and Australia. 
 Such silicified wood has also been shown to be gold-bearing. 
 
 The concentration of quartz in one place rather than in another, 
 its deposition between certain beds and along certain fractures rather 
 than elsewhere, are the results more of simple physical conditions 
 than of complicated chemical reactions, and are due to causes to be 
 discussed in considering the structural geology of this district. 
 
 2. The Gold. 
 
 The waters of the ocean contain gold. In 1851 Malaguti and 
 Durocher determined the occurrence of silver, but did not extend 
 their inquiries into the question of the presence of gold in sea- 
 water. This fact was first accurately determined by Sonstadt in 
 1872.* His experiments were not quantitative, but he stated, in 
 parenthesis, that the amount was "certainly less than 1 grain in the 
 ton."f More recently, however, Miinster found an average of 5 
 milligrammes per ton.J In endeavoring to arrive at an approximate 
 estimate it must be remembered that local conditions, such as the 
 temperature of the water, will affect the amount in solution. Son- 
 stadt's researches were made with water obtained near Ramsey, in 
 the Isle of Man, while Miinster got his from the Kristiania Fjord. 
 In each case the sea-water was that of a northern latitude. In 
 warmer regions it is probable that precipitation, due to the presence 
 of putrescent organic matter, may diminish the amount of gold 
 held in solution. Let us, however, take 5 milligrammes (equiva- 
 lent to y 1 ^ of a grain) as an approximation. This, though in itself 
 a minute quantity, will be found to represent an enormous total 
 amount of gold in the waters of the ocean. From the results ob- 
 tained from the careful soundings carried out by the Challenger and 
 similar scientific expeditions, it has been computed that the ocean has 
 an average depth of 2500 fathoms, and that it contains 400 million 
 cubic miles of water.|| This is equivalent to about 1 ,837,030,272,000 
 
 * "On the Presence of Gold in Sea-Water," E. Sonstadt, Chemical News, Oct. 4, 
 1872, xxvi., p. 159. 
 
 f Sonstadt is often incorrectly quoted as having shown that sea-water contains 1, 
 grain of gold per ton. 
 
 J The amount of silver was determined to be 20 mg. per ton. See " On The Pos- 
 sibility of Extracting the Precious Metals from Sea- Water," Journal of the Society of 
 Chemical Industry, April 30, 1892, xi., p. 351 ; abstract from Norsk Tekniak Tidsskrift, 
 vol. 10, No. 1. See note in the Chemical News, Oct. 4, 1872, xxvi., p. 161. 
 
 || Geikie's Text-book of Geology, 2d ed., p. 33. 
 
20 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 million tons, which, upon the basis of 5 milligrammes per ton, 
 would represent 10,250 million tons of gold. By way of contrast, 
 it may be added that, according to Soetbeer, Leech, and others, 
 the gold-production of the world, from the beginning of 149-5 to 
 the end of 1892, a period of exactly four centuries, has amounted to 
 only 5020 tons. The present output is equal to about 200 tons per 
 annum.* 
 
 The gold in sea-water is kept in solution as an iodide, f The 
 amount of free iodine present in the ocean is very minute ;{ but a 
 large proportion of that element occurs combined as an iodate of 
 calcium. From the results of a series of six experiments, Sonstadt 
 found that a cubic mile of sea-water contains about 17,000 tons of 
 iodate of calcium or 11,072 tons of iodine.|| This represents the 
 occurrence in the entire ocean of no less than 4,428,800 million tons 
 of iodine. 
 
 The iodine which maintains the gold in solution is obtained from 
 the iodate of calcium. Gold is soluble in extremely dilute solutions 
 of iodine, which under ordinary conditions are in turn readily 
 reduced by organic matter. That the gold in the sea is not precipi- 
 tated is due to the presence of the iodate of calcium in which it is 
 not soluble but which, being readily decomposed by putreseible or- 
 ganic matter, liberates the iodine required to keep the gold in solu- 
 tion. 
 
 There is reason to believe that the sea- waters of to-day contain 
 much less iodine than those of former geological periods. ^[ That 
 there is so little free iodine in the ocean is due to causes parallel to 
 those which bring about the noteworthy absence of carbonate of 
 lime. Marine animals abstract the latter while marine plants absorb 
 the former. How great is the work done in this way, is evidenced 
 by the dimensions of the coral reefs and by the Extent of the forami- 
 niferous and other marine limestones. 
 
 The abstraction of iodine is no less striking. Sea-weeds, and 
 more particularly those which grow at great depths, are the chief 
 source of the iodine of commerce.** When, after a storm, such sea- 
 
 * The colonies of Australasia, since 1851, have produced 2830 tons, of which 
 Bendigo contributed 375 tons. 
 
 f The Chemical News, October 4, 1872, xxvi., p. 159. 
 
 J /^W., April 26, 1872, xxv., p. 196. 
 
 \ Ibid., April 26, 1872, p. 197. 
 
 || Ibid., May 24, 1872, p. 242. 
 
 If Thomas Sterry Hunt, Chemical and Geological Essays, p. 142. 
 
 ** It is also recovered from the nitrate of Chili. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 21 
 
 weeds are cast upon the shores of Great Britain,* France and Swe- 
 den, they are collected and burnt, and from their fused ashes, termed 
 " kelp," the iodine is subsequently extracted by a simple chemical 
 process. From 13,000 kilos of kelp about 100 kilos of sodium car- 
 bonate and 15 kilos of iodine are obtained. f 
 
 That iodine is not now so plentiful in the sea as during former 
 geological periods has been suggested by chemical investigations into 
 the composition of rocks. Certain sedimentary formations contain 
 notable quantities of it. It has been found in some aluminous shales 
 in Sweden, and also in certain varieties of coal and turf.J The 
 saline waters of several springs contain large amounts of it. Even 
 rain-water has been known to give a recognizable iodine reaction 
 when tested, such iodine having been obtained by the agenc}* of 
 winds which have been blowing over certain areas of the sea where 
 it was being liberated by the action of organic matter upon the iodate 
 of calcium. 
 
 Let us now return to Bendigo. The conditions which prevailed 
 during the time when the Silurian seas washed the earth's surface, 
 were no less favorable to the solution of gold than those which ob- 
 tain to-day. It is indeed probable that the waters of the paleozoic 
 ocean contained more gold than those of the present geological 
 period. When the sediments sunk to the bottom they carried with 
 them, entangled amid the silt and sand, a large proportion of sea- 
 water, most of which was subsequently yielded up as they were 
 pressed down by the weight of the overlying deposits. The sea- 
 water as it was rejected by the solidifying strata, left behind it a re- 
 siduum which contained in a highly concentrated form the original 
 constituents of the Silurian ocean. The sediments which fell to the 
 ocean floor also contained portions and fragments of vegetable life 
 which in their decay served to decompose the iodate of calcium con- 
 tained in the residual sea- water and so set free the iodine. This is 
 a very active element and would at once form a fresh combination. 
 The excess of iodine thus obtained may have served as a solvent for 
 any particles of metallic gold which by mechanical means accompa- 
 nied the sands laid down beneath the sea and which thus became 
 added to that already derived from original chemical solution in the 
 waters of the ocean. 
 
 * Particularly the western isles of Scotland, and the west coasts of Wales and 
 Cornwall. 
 
 f The Principles of Chemistry, D. Mendeljeff, vol. i., p. 490. 
 J Fownes's Chemistry, p. 185. \ The Chemical News, May 17, 1872, xxv., p. 231. 
 
22 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 The great body of slates and sandstones, not less than seven miles 
 in thickness, was thus slightly but distinctly gold-bearing. It is 
 so still ; the amount of the precious metal has remained practically 
 the same and the changes which have occurred have merely brought 
 about its less uniform distribution. 
 
 As the sediments were further consolidated, the vegetation which 
 they originally contained became disintegrated into its elements, and 
 the iodine which it had abstracted from the sea-water when alive 
 was now yielded up. The iodine thus derived became another fac- 
 tor in the solution of the gold which was disseminated through the 
 solidifying strata. 
 
 From a state of eveii dissemination through great rock-masses to 
 its concentration along certain lines of fracture which we call reefs, 
 the gold arrived through the agency of the water still retained by 
 those rock- masses. The geological history of the district has shown 
 that from various causes the heat required to make those underground 
 waters intensely active was at hand for long periods. It is probable 
 that the time of the extrusion of the granite was in this respect one 
 of unwonted chemical activity. So also was the later period, when 
 the lava dikes penetrated the overlying strata. 
 
 As an iodide, the gold readily circulated through the medium of 
 the waters occurring in the rocks. We know gold to be readily 
 soluble, even in extremely dilute iodide solutions. It would be 
 wrong, however, to suppose that this or any other one chemical 
 agency was the universal solvent for the precious metal. There is 
 reason to suppose that in different formations and under diverse con- 
 ditions gold is soluble in varying combinations, all having a common 
 want of stability. It has been suggested by Le Conte and others, 
 and some recent discoveries* in the mines have tended to confirm the 
 supposition, that the gold of certain lodes has been deposited from 
 the solutions of the persulphate of iron. Alkaline sulphides. have 
 long been mentioned in the text-books as the chief agents in the dis- 
 solving of the metallic sulphides, and very pretty chemical formulae 
 have been evolved to explain the resulting complicated reactions.f 
 
 * "Gold Deposits in the Quartzite Formation of Battle Mountain," F. Guiterman, 
 Proceedings of the Colorado Scientific Society, vol. iii., part iii. 
 
 f The supposition that gold is insoluble in alkaline sulphides requires modifica- 
 tion. At the June, 1893, meeting of the Colorado Scientific Society, Mr. L. G. 
 Eakins reported the results of recent experiments, which show that fine gold, 
 digested for four to five days in a cold, strong yellow solution of ammonium sul- 
 phide, has a solubility equal to 2 per cent. Weak solutions, with seven days' diges- 
 tion, gave confirmatory results. Sodium sulphide also was found to be a solvent. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 23 
 
 Occasionally gold is found free from association with metallic sul- 
 phides ; then Bischof 's experiments are quoted, and its origin is put 
 down to a silicate of gold soluble in alkaline waters. Again, gold 
 readily combines with free chlorine, forming a salt easily soluble in 
 water. The chloride of gold has, however, not been considered as 
 likely to exist in nature because of the rarity of the occurrence of 
 free chlorine and because of the instability of the compound which 
 it forms with gold. The latter quality is not peculiar, but charac- 
 teristic of all the salts of gold as we know them. Free chlorine 
 does exist in nature, and though not frequently detected, this is not 
 to be wondered at, seeing that its occurrence is usually associated 
 with that of hot water or steam. Volcanoes, especially during times 
 of temporary quiescence, emit large quantities of hydrochloric acid,* 
 and the rims of the volcanic vents, then called "fumaroles," show 
 incrustations of chloride of iron, chloride of ammonium, etc. The 
 comparatively large amounts of such salts as exist in sea- water, which 
 were found at Vesuviusf was one of the facts used in support of the 
 theory that the steam of volcanic eruptions came from the ocean. 
 That these and other compounds, including hydrochloric acid, owe 
 their origin to free chlorine, and were formed in the presence of hot 
 water and steam, is most probable. Therefore it would seem well 
 to add the chloride to the other probable combinations in which gold 
 may circulate underground. 
 
 In the great laboratory of nature, the chemical changes which take 
 place in the long periods of time with which we have to deal must 
 be of an infinite variety, and therefore no number of chemical formu- 
 la can represent the reactions which have followed each other from 
 the moment when the -gold was liberated by the disintegration of 
 some pre-Silurian rock to this later day, when the miner finds it en- 
 closed in the quartz of the reefs. Therefore, while it is suggested 
 that as an iodide it may have travelled through the waterways of the 
 Silurian rocks, it is not meant that in its long journeyings before it 
 arrived at the place where it is now found, it did not pass through 
 many changes of chemical combination. 
 
 The precipitation of gold from solution can be brought about in 
 many ways. More than twenty-five years ago certain members of 
 the Geological Survey of Victoria carried out a series of experiments 
 
 but to a very slight degree only. Mr. Eakins is still prosecuting this series of in- 
 teresting experiments. 
 
 * Judd's Volcanoes, p. 213. 
 
 t Palmieri's Vesuvius, p. 121. 
 
24 ORIGIN OF GOLD-BEARING QUARTZ OP BENDIGO REEFS. 
 
 which yet remain our main source of information on this subject. In 
 1864, an accidental discovery by Richard Daintree led to the de- 
 termination by him and his colleague, Prof. George H. F. Ulrich, of 
 certain conditions under which the precious metal is deposited from 
 solution.* It was demonstrated subsequently by a number of care- 
 ful experiments made by Wilkinson,f that organic matter, in any of 
 the ordinary forms in which it is found to occur in the alluvial 
 drifts, is readily capable of precipitating the gold of even the weakest 
 solutions, and of depositing it as a thin metallic coating upon other 
 particles of gold or upon any of the sulphide minerals, such as pyrite, 
 galena, or blende, with which its occurrence is usually associated. 
 
 Several years later, in 1871, Daintree was in London and at Dr. 
 Percy's laboratory, at the Royal School of Mines, commenced 
 another series of experiments. In different bottles he placed solu- 
 tions of chloride of gold in strong solutions of chloride of sodium, 
 containing a piece of pure rock-salt, and to each he added a crystal of 
 one of the several metallic sulphides commonly found in gold-ores. 
 Four years later, and before any results had been obtained, he died. 
 The chemical reactions which he had set to work were, however, pro- 
 ceeding slowly but surely. I now quote, Mr. Richard Pearce, who 
 was an eye-witness of both the beginning and the consummation of 
 these experiments. 
 
 " When Daintree died, one of the bottles, namely, that containing a gold solution 
 and a crystal of common pyrite, was removed to Dr. Percy's laboratory in Glouces- 
 ter Crescent, and there, in 1886, the work which Daintree had begun came to frui- 
 tion. On the smooth surface of the crystal of pyrite there had been deposited a 
 cluster of crystals of gold." 
 
 * The following interesting account of what has become an historical event was 
 given to me by my distinguished friend, Prof. Ulrich, now of the University of 
 Otago, New Zealand, and with his permission, I reproduce it here: 
 
 "I was engaged in the laboratory analyzing a zeolitic mineral, whilst Daintree 
 himself was busy with some photographs. Suddenly he made ejaculations of aston- 
 ishment, and on my asking the reason, he showed me a small, common medicine- 
 bottle, which contained (more than half full) a water-clear fluid in which floated 
 a part of the cork. The cork remaining in the neck of the bottle was acid-eaten. 
 At the bottom of the bottle there was a large speck, or rather little nugget, of bright 
 gold. He explained that he had made a concentrated solution of chloride of gold 
 for the purpose of toning his photographic prints. He had placed in it a small 
 speck of gold. * And now see (turning the bottle upside down), 'the speck has grown 
 to such a size that it won't go through the neck of the bottle.' We both agreed that 
 the organic matter of the cork had been the cause of the decomposition of the solu- 
 tion and the growth of the gold." 
 
 f The late Mr. Charles Wilkinson, Government Geologist of New South Wales, 
 at that time junior assistant in the Geological Survey of Victoria. 
 
ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 25 
 
 It had taken fifteen years to obtain the result, and the man who 
 started the investigation did not live to see his work fulfilled ; but 
 what, it may well be asked, is the brief time of even a generation 
 when compared to those vast aeons during which Nature, in her 
 greater laboratory, is carrying out operations similar to these? 
 
 It is interesting to be able to add as a sequel to the above that in 
 the ore of the St. Louis mine, in Gilpin county, Colorado, crystals 
 of pyrite have been found which, while in themselves non-aurifer- 
 ous, were yet dotted over with clusters of crystalline gold remarka- 
 bly similar to those obtained by Daintree's experiment* 
 
 The persulphate of iron, which is also a vehicle for the removal 
 of gold from one place to another, is reduced by organic matter, 
 with the formation of gold-bearing pyrite. Under like conditions 
 silicate of gold solutions would precipitate their gold. Again, me- 
 tallic sulphates or alkaline sulphide waters containing metallic sul- 
 phides in solution would, on meeting alkaline carbonates in the 
 presence of organic matter, be compelled, by reduction and neutrali- 
 zation respectively, to form a deposit of metallic sulphides, f Finally, 
 iodide solutions are readily reduced by organic matter or by ferrous 
 sulphate, while the presence of both together would lead to the 
 formation of an auriferous pyrite. 
 
 We need now to recall the fact that the original sediments con- 
 tained imbedded with them numerous remains of the organic life of 
 the ancient seas, many of whose forms were subsequently preserved 
 in the rocks as the fossils which now enable us to determine the 
 stratigraphical position of the slates and sandstones. Other rem- 
 nants of the more minute organisms such as abounded in the waters 
 of the ocean, though they left behind them no recognizable forms, 
 yet were doubtless mixed among the silt and mud which fell to the 
 bottom of the Silurian seas. Such organic matter in process of time 
 became decomposed irito its constituent elements, those which were 
 soluble being removed by underground waters while the insoluble 
 remained to undergo further decomposition. In this case, as often 
 happens in the laboratory of Nature, the solvent and the precipitant 
 formed part of the same substance, whose disintegration liberated 
 the one from the other, both, however, to meet again and to react 
 upon each other at a later period. Thus the iodine, which is a sol- 
 vent for gold, was set free while the carbon, which is a precipitant, 
 
 * My authority is again Mr- Richard Pearce. 
 f Le Conte's Elements of Geology, p. 245. 
 
26 ORIGIN OF GOLD-BEARING QUARTZ OF BENDIGO REEFS. 
 
 remained in the residue and became converted into the graphitic 
 material which darkens the rock encasing the quartz lodes. 
 
 This graphitic material was the precipitant for the gold solutions. 
 Its occurrence in certain lodes has been pointed out by others* but 
 its very frequent association with gold quartz has not been fairly 
 recognized. In the main auriferous belt of California, passing 
 through the counties of Amador, Calaveras, Tuolumne and Mari- 
 posa, an encasing formation of black slate is known by experience 
 to be a favorable indication, while a gray or greenish-gray country- 
 rock is considered less encouraging. At Amador City, in the county 
 of the same name, I have seen men coming up from underground 
 with faces and hands all sooty black by reason of contact with the 
 graphitic slate which there and elsewhere in that region encloses the 
 quartz veins. In New Zealand, more particularly in the province 
 of Otago, the gold-bearing lodes are similarly characterized by a 
 black selvage, the somber tint of which is due to carbonaceous ma- 
 terial. In the mining districts of the continent of Australia, as 
 well as in the gold-fields of the island of Tasmania, the slates and 
 metamorphic schists, which so generally form the prevailing country- 
 rock, are dark, and the clay which lines the walls of the reefs is 
 black and graphitic. Such is the case also in the mines of Bendigo. 
 It is not, therefore, necessary to go far to find an agent capable of 
 precipitating the gold from its state of solution in the underground 
 waters of the rocks, f 
 
 That gold does occur in solution in the underground waters of to- 
 day has been shown by the evaporation of large quantities of ordt- 
 nary mine-water and the finding of gold in the residuum,^ also by 
 its occurrence in the incrustation of boilers using mine-water. It 
 has been proved By the examination of old mine timbers left in 
 abandoned workings and the discovery in the decayed and often 
 silicified 'wood of crystals of pyrite which 'were distinctly gold- 
 bearing. || Furthermore, it may be added that in the gravel of the 
 deep leads, at Ballarat, for example, there has been found driftwood 
 
 * As, for instance, by Sandberger, in connection with the veins of the Erzge- 
 birge. 
 
 f How far electro-chemical and electro-magnetic forces may have aided these re- 
 actions cannot be estimated. That they took some part is highly probable. 
 
 J First proved by Daintree. 
 
 % Also by Daintree, at the mines at Maryborough. 
 
 || Notes on the Physical Geography, Geology and Mineralogy of Victoria, by A. K. C. 
 Selwyn and G. H. F. Ulrich. Melbourne, 1866. 
 
ORIGIN OF GOLD-BEARING QUARTZ OP BENDIGO REEFS. 27 
 
 yielding assays of from a few pennyweights to several ounces of 
 gold per ton.* 
 
 The occurrence of the metallic sulphides, such as arsenical and 
 ordinary iron pyrites, galena, and blende, the minerals most com- 
 monly found at Bendigo in association with the gold, brings up a 
 large field of conjecture. Sandbergerf showed that iron, zinc, lead, 
 copper and other metals occurring in lodes can also be found in cer- 
 tain silicates common to the crystalline rocks, such as olivine, augite, 
 hornblende and mica. His deductions have not been, however, en- 
 tirely accepted. At Bendigo the lode-formation, though evidencing 
 metamorphic action, is yet sedimentary. It may, perhaps, be sug- 
 gested that the granite contributed the metallic sulphides associated 
 with the gold and quartz, but there is no evidence to support such 
 an explanation. While the frequency of the occurrence of ore- 
 deposits in association with eruptive rocks is a fact now widely re- 
 cognized, yet it has given rise to generalizations not altogether war- 
 ranted. In this particular district the contact is not a place of ore- 
 deposition, and the main series of producing mines is seven miles 
 distant. There are, it is true, certain anticlinal formations of quartz 
 not far from the granite ; but they appear to have no relation to tl}e 
 contact, and they are not economically of any importance. The 
 geological evidence of the region has suggested that the granite was 
 a factor in the process of ore-deposition, but it does not indicate 
 that this rock was the source of the gold or of the associated sul- 
 phides. 
 
 In this connection I would hazard the remark that the near 
 neighborhood of igneous rocks is favorable to the occurrence of ore- 
 bodies, not always or necessarily because such rocks were the origin 
 of the precious metals which were leached out from them, but often 
 because the extrusion of such eruptive rocks afforded the heat and 
 steam which gave an intensified chemical activity to percolating 
 solutions. 
 
 The Silurian sediments were obtained from the erosion of pre- 
 existing rocks, whose disintegrated particles probably contained the 
 material required to form the sulphide minerals of the reefs. 
 Whether the metals were dissolved in the waters of the palaeozoic 
 
 * Investigated by the above-mentioned, and also by J. Cosmo Newberry, analyst 
 to the Geol. Survey of Victoria. 
 
 f Engineering and Mining Journal, March 22 and 29, 1884, xxxvii., pp. 218 
 and 232. Translation of first chapter of '* Untersuchungen iiber Erzgiinge," by 
 Fridolin Sandberger. Wiesbaden, 1882. 
 
28 ORIGIN OP GOLD-BEARING QUARTZ ON BENDIGO REEFS. 
 
 seas and were subsequently chemically precipitated, or whether they 
 were deposited by mechanical agency among the silt and sand which 
 fell to the ocean bed, is a question not now to be determined. 
 
 In the reefs of the Bendigo gold-field the metallic sulphides are 
 present in an unusually small proportion. Iron pyrites is much 
 the most abundant. A great deal of the richest ore of the deepest 
 workings of the mines is a clean white quartz, almost entirely free 
 from any accessory minerals. Such quartz frequently contains the 
 gold in an extremely coarse form, in pieces weighing many penny- 
 weights.* The presence of pyrite is not necessarily an evidence of 
 the poverty or richness of the quartz. Rich ore-bodies often con- 
 tain a good deal of it, just as poor ones sometimes do. Other min- 
 ing-districts afford a similar experience. We must recognize that 
 the sulphates of iron act very differently with an increase or de- 
 crease of the oxygen they carry. Ferrous sulphate, FeO, SO 3 , is a 
 precipitantf for gold solutions, while ferric sulphate, Fe 2 O s , 3 SO 3 ,J is 
 a solvent. May not this fact help to explain the irregularity of the 
 phenomena attending the presence of pyrite in gold-ores ? 
 
 The limitations to the length of this contribution must prevent 
 the discussion of theories explanatory of the process by which the 
 gold and quartz were actually brought to the place where we now 
 find them. Modern teaching and experience has advanced that 
 theory of ore-deposition which has been, not at all happily, called 
 t( lateral secretion." It is to the effect that the origin of the pre- 
 cious metals as found in lodes is to be ascribed to the immediately 
 encasing rock, out of which they have been leached by solutions, 
 which afterwards by endosmotic flow, penetrated the walls of the 
 fissure and there deposited the gold and silver. Such an explanation 
 is, I respectfully submit, more in harmony with the teachings of a 
 professor's laboratory than with the testimony of underground ob- 
 servation. No theory so narrow as that framed on a phenomenon 
 as specific as endosmosis can live in the air of the mines where the 
 modes of occurrence of the ore have an infinitude of variety which 
 even the most general of explanations can hardly hope to cover. 
 As our stock of ascertained facts slowly accumulates, as each dis- 
 
 * At the Lazarus Mine, at a depth of over 2000 feet, I saw pieces of gold ex- 
 ceeding an ounce in weight in a large reef of clean, white, splintery quartz. 
 
 f It is the precipitant employed in the chlorination-works of California and else- 
 where. Charcoal is also used for the same purpose. 
 
 J The formula is not rigid. The so-called sesqui-sulphates of iron are of vari- 
 able composition. 
 
ORIGIN OF GOLD-BEARING QUARTZ ON BENDIGO REEFS. 29 
 
 tant mining district sends in its quota of recorded observations, we 
 shall, I believe, find that " lateral secretion " in its narrowest mean- 
 ing is rarely tenable, that is, that while the material of ore-deposits 
 may have been and probably was derived from the leaching of the 
 rocks, it did not necessarily or often come only from those which are 
 immediately adjacent to the walls of the lodes. In the case of the 
 Bendigo " saddles " we are led to believe that the gold and the quartz 
 were derived from the mass of the surrounding formation rather 
 than from that small portion only which immediately adjoins the 
 reefs. In the process of ore-deposition and lode -formation this 
 gold-field was a part of a greater area, in which similar phenomena 
 of segregation* took place, an area which included nearly all of the 
 numerous and productive gold-mining districts of the colony of 
 Victoria. Bendigo was especially favored because of the very pe- 
 culiar structure of its beds of slate and sandstone. 
 
 It may be objected to the general explanation which has been 
 offered with regard to the origin of the gold and the quartz that if 
 it be accepted as true, all sedimentary rock formations should be 
 equally capable of profitable exploitation. The answer is obvious, 
 namely, that to the miner the mere dissemination of gold in rocks is 
 a fact economically of no importance, since it is only by its concen- 
 tration in certain quantities and in certain forms of ore-deposit that 
 it can repay him for the toil and expense of its extraction. In the 
 Silurian rocks of the Bendigo district conditions obtained and 
 agencies were at work which were particularly effectual in collecting 
 the gold from its wide and even dissemination to its concentration 
 in the reefs. 
 
 The richness of the gold-field is owing primarily to two causes, 
 the structure of the country-rock whose extreme and very regular 
 folding gave rise to unusual facilities for the percolation of under- 
 ground waters, and the occurrence in the slates and sandstones of a 
 precipitant able to compel the deposition of the gold. 
 
 It is a striking fact that while the anticlines necessarily alternate 
 with syncliues, the latter are not the places of ore-deposition. " In- 
 verted saddles," as the miners call them, do indeed occasionally 
 occur; but they are not economically of any importance. The ex- 
 planation is a simple one. By the mechanical principle of the arch 
 
 the anticlinal structure tends to preserve a passage for mineral solu- 
 
 . . 
 
 * This word " segregation " the separating out of material and its regathering 
 together elsewhere best covers the process of lode-formation in this particular 
 region. 
 
30 ORIGIN OF GOLD-BEABING QUARTZ ON BENDIGO REEFS. 
 
 FIG. 14. 
 
 Drawing of Bendigo made in 1851. 
 
ORIGIN OF GOLD-BEARING QUARTZ ON BBNDIGO REEFS. 31 
 
 tions, while on the contrary the basin or trough, formed by the 
 synclinal arrangement of the beds, tends by the action of gravity to 
 become closed. It is not probable that the apex of the anticlines 
 was marked by an open way ; but we are justified in supposing that 
 along the anticlinal axes there were portions of rock more loose and 
 more permeable than the country surrounding them. These we may 
 liken to arched canals through whose long passages mineral solu- 
 tions have circulated from pre-Devonian times till now, bearing 
 with them that golden freight which by reason of the reducing 
 action of the carbonaceous matter lining their walls they were com- 
 pelled little by little to lay down. 
 
 Thus we arrive at a stage when from wide and uniform dissemina- 
 tion through enormous rock-masses the gold and the quartz have 
 become concentrated along certain lines and in certain localities, but 
 nature is never at rest; they are no sooner laid down than they be- 
 come again wanderers through the underground waterways. The 
 causes operating to remove them from one place and to concentrate 
 them in another are forever at work. We speak of secondary deposi- 
 tion in cases where we think we clearly recognize the removal of 
 metallic ore from one place to another; but as a matter of fact all 
 the ore-deposits of the mines are concentrations, and in their nature 
 secondary, from the period when their constituent parts formed a 
 portion, relatively large or infinitely small, of the first sediments 
 laid down upon the floor of the ocean to that time long afterward 
 when the pick of the miner disturbs that which for ages has been 
 going through a process of continual change and evolution. 
 
 Thus the silica which as fine sand fell to the bed of the sea, in 
 process of time united with other elements and became a part of a 
 complex mineral which we call a silicate. That silicate, by the rever- 
 sal of the reactions which had brought it into existence, became subse- 
 quently disintegrated, the silica was set free, and as quartz later on 
 became the matrix enclosing the gold. From that state of admix- 
 ture it was separated by the contrivances of man or by the less noisy 
 and more powerful agencies of heat and cold, wind and rain, to be 
 swept into the running stream which carried it into the waters of 
 the ocean in whose silent depths it was destined again to " sow the 
 dust of continents to be." 
 
 Similarly the Silurian slates and sandstones may have been them- 
 selves derived from the erosion and disintegration of the granites, 
 other portions of which afterwards intruded among them. Or, 
 again, there is reason to believe that the granite may have been 
 
32 ORIG.IN OF GOLD-BEARING QUARTZ ON BENDIGO REEFS. 
 
 formed by the extreme metamorphism of the lowermost members of 
 the Silurian series. Upbuilding and disintegration in the mineral 
 creation like life and death in the organic world, are but correlative 
 parts of one continuous process. They are different aspects of that 
 indestructibility of matter and transmutation of energy which are 
 taught no less by the formation of a quartz reef than by the unfold- 
 ing of a flower. 
 
 At that point in the long sequence which marks the present time, the 
 eye lingers on rolling woodland and winding road, grassy meadows 
 and fleecy flocks, glancing from the busy activity of the railway to 
 the peaceful quietness of the farm, to be finally arrested as it catches 
 the gleam of the Bendigo mines, white islands in the dark blue sea 
 of the lovely Australian bush, that vast forest of Eucalyptus whose 
 leafy waves have replaced the watery wastes of palaeozoic times. 
 
 Fig. 14 is a reproduction of a drawing of the Bendigo field as it 
 appeared in 1851. The upright mass of quartz in the foreground 
 is the " west leg " of a saddle- formation, while just beyond the two 
 pools of water (now ornamental lakes in the grounds of Mr. George 
 Lansell's residence) there is seen an actual saddle, outcropping at 
 the surface. 
 
/o 
 Subject to Revision. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 LA GARDETTE: THE HISTORY OF A FRENCH GOLD 
 
 MINE. 
 
 BY T. A. RICKARD, ALLEMONT, ISERE, FRANCE. 
 
 (Baltimore Meeting, February, 1892.) 
 
 THE mountains of the picturesque Dauphine, in southeastern 
 France, have long been known to collectors as the source of many 
 minerals of rare occurrence; but they contain also several mines, 
 which, though less known, date from the time of the Saracens, 
 many centuries back, to that of the graduate from the JScole des 
 Mines. 
 
 In the department of the Isere, upon the cliffs of Villard Ey- 
 mond and overlooking the lovely valley of the Oisans, is the his- 
 toric gold-mine of France, a mine interesting as much for its record 
 as for its geological features. 
 
 The gold-bearing character of the quartz of La Gardette was 
 known to the Greeks, the Romans, and later to the Saracens, all of 
 whom at various periods extracted the gold of the outcrop which 
 ribs the mountain-side. Mention of this mine is found in certain 
 rare manuscripts of the seventeenth century, but it was in 1733 that 
 the first serious working was inaugurated. In that year the ex- 
 ploration of the vein was undertaken by order of the king, much 
 to the disgust of the inhabitants of Bourg d'Oisans, to whom it has 
 been, both in earlier and later times, a source of revenue, either di- 
 rectly by the extraction of small quantities of gold-ore or indirectly 
 by the attraction which it has presented to passing travellers. The 
 working of the mine by the State had no results of importance and 
 shortly ceased. In 1765, the mine was again given over to the 
 peasantry. In 1776, the king' conceded to his brother, the Comte 
 de Provence, afterwards Louis XVIII., a large number of mines 
 in this district. La Gardette was included ; but work under 
 this grant was directed to the mines of Les Chalanches, near 
 Allemont, in the neighboring commune. Here a foundry was 
 erected under the supervision of M. Binelli, considered one of the 
 most celebrated mineralogists of his time. In 1781, Binelli was 
 replaced by Schreiber, a Saxon engineer, -whose name is interwoven 
 
2 LA GARDETTE: THE HISTORY OF A FRENCH GOLD MINE. 
 
 with that of nearly all the old mines of this part of Europe. At 
 that time a peasant named Laurent Gardent came to Allemont to 
 see M. Schreiber and to show him certain specimens of gold-quartz 
 recently extracted from the lode at La Gardette. Schreiber made 
 an examination, was much impressed with what he saw, and forth- 
 with started for Paris, where, upon his arrival, it was decided to 
 commence at once the exploitation of the mine. Systematic work- 
 ing was then started under the personal supervision of the best 
 mining engineers of that period. 
 
 This discovery of a gold-mine is said to have produced a great sen- 
 sation in Paris. All the literature of that time makes mention of 
 the matter, and the arrival in 1783 of the first ingots of gold aroused 
 great enthusiasm at the Court. 
 
 In 1786, the Comte de Provence caused a medal to be struck, the 
 gold of which was the product of this mine. The matter was 
 placed in the hands of L? Academic des Inscriptions et Belles Lettres, 
 which chose Dupre to execute the designs. One side of the medal 
 represented Louis XVI., and the other the Comte de Provence, in 
 the act of offering to the king the first product of a French gold- 
 mine. 
 
 The cost of this medal was put down at 8000 livres, and it has 
 been sarcastically said that this represented all the results thus far 
 obtained by the enterprise. It certainly marked the most brilliant 
 period of the history of the mine, for soon after, in 1788, work was 
 discontinued. It is reported that gold was found chiefly in the 
 upper levels, but that the irregular distribution of the precious 
 metal, together with other circumstances, caused the abandonment 
 of active exploitation. Among the "other circumstancts " it is safe 
 to include the insufficient quantity of gold in the ore; for in those 
 days, as now, there were men who knew how to avoid laying un- 
 necessary stress upon this somewhat important feature of gold- 
 mining. 
 
 After 1788, followed a blank period, during which the mine was 
 the property of the commune. The extraction of specimens, both 
 of gold and of rock-crystal, was actively carried on, and helped to 
 beautify collections in many of the less distant towns. More par- 
 ticularly it was then that the basis was laid for the fine collection now 
 to be seen at the museum in Grenoble. 
 
 Under the first Empire no work was done on the mine ; but the 
 mining engineer-in-chief at that time, Hericart de Thury, was in- 
 structed to write a report, which appeared in the Journal des Mines, 
 
LA GARDETTE: THE HISTORY OF A FRENCH GOLD MINE. 3 
 
 in 1806. The times were troubled, and the complications of politics 
 allowed the mine to remain in oblivion until 1837, when a fitful re- 
 opening took place. In 1839, the property was acquired by M. Van 
 de Velde for a Parisian company, which, under the management of 
 M. Graff, caused the mine to be re-opened in 1841. Some very rich 
 pockets of specimen-gold were found, but no serious prospecting was 
 done, and no important results were obtained. 
 
 The mine then passed through the hands of several proprietors, 
 under whose management far more gold was expended than was re- 
 turned, and more than was returned was stolen. 
 
 In 1862, La Gardette came into the possession of two Englishmen, 
 Messrs. Fisher and Watson ; but, upon the departure of the latter 
 for the more productive mines of Australia, the former became dis- 
 couraged and ceased work. Since then nothing has been done to 
 forward its development, save the writing of reports by the suc- 
 cessive mining engineers-in-chief, to whom it seems always to have 
 furnished the subject of a sort of graduation -essay. 
 
 Recently the re-opening of La Gardette was considered by the 
 English company now working the mines at Allemont ; and the 
 writer was called upon to examine it. The results of that examina- 
 tion, as stated below, bring the history of La Gardette up to date. 
 
 The history of the mine, as outlined above, finds a ready explana- 
 tion in the study of the conditions under which the gold occurs. An 
 obtuse disregard of the facts as disclosed in the workings and a belief 
 in wild theories of ore-deposition have been the causes of the re- 
 peated failures to make it profitable. 
 
 The gold of La Gardette occurs in a quartz-vein traversing the 
 gneiss, which in this district has a great variety of hardness and 
 composition.* The lode is of extraordinary regularity in strike, 
 dip and parallelism of walls. It runs nearly due east and west,f 
 and makes an angle of 75 with the horizon. 
 
 The gangue is almost entirely quartz, with a highly developed 
 banded or ribbon-structure. Slickensides characterize the walls. The 
 minerals accompanying the quartz are galena, iron and copper 
 pyrites and (rarely) gray copper. It has been noted that the coarse 
 galena J is favorable to the presence of gold. The richest quartz 
 
 * The French engineers variously apply to it the terms gneiss, protogine and 
 crystalline schists 
 
 f Or, as the French simply put it " vers sept d huit heures." 
 J " A grandes facettes." 
 
4 LA GARDETTE : THE HISTORY OF A FRENCH GOLD MINE. 
 
 is that which has a bluish-black color,* an experience in har- 
 mony with that of other gold mining districts. 
 
 This is not the only known occurrence of gold in the district, 
 though it is the only one which has risen to the dignity of a 
 mine. M. de Thury, mining engineer-in-chief under the first em- 
 pire, has left the record^ that there are several gold-deposits in 
 the department of the Is&re : 
 
 1. At Portraut, at the foot of the glaciers of the Grandes Rousses, 
 where it occurs in association with argentiferous lead ore 
 
 2. At Auris, on the southern slope of the same range, and nearly 
 opposite La Gardette, in a complex lead-copper ore, associated with 
 antimony. 
 
 3. At Mollard, near Allemont, in argentiferous galena; also in 
 the copper pyrites of La Corchette and in that of Les Chalanches, 
 Allemont. 
 
 In later times I have found it in noteworthy quantities in the 
 quartz of the Mine des Arabes, at Allemont, where it is associated 
 with galena, blende and pyrites, but occurs more particularly in 
 thin seams of maroon -colored earth. It is found in the argentif- 
 erous galena of Grand Clos, near La Grave, as well as in certain 
 quartz-veins above La Yillette. Nearly all the ores of this district 
 which I have had cause to assay have shown traces of gold. 
 
 Returning to La Gardette, we may consider briefly the geological 
 conditions. The gneiss, traversed as already remarked by this lode, 
 is overlain by the dolomite of the Trias and that in turn by the 
 lime-sh:ile of the Lias, both of which formations have been identi- 
 fied by their fossil remains. The Trias is but slightly represented, 
 and here varies in thickness from 5 to 20 meters. The Lias is repre- 
 sented by lime-shale, but its upper horizon is diversified by the 
 slate, the contorted bedding of which is a striking feature of the 
 cliffs above Bourg d'Oisans. In it occur the slate-quarries of Alle- 
 mont and Oz. ... , 
 
 The vein does not penetrate the overlying secondary formations, 
 but ceases at the upper eroded edges of the gneiss. Where the vein 
 ceases, two stringers or small seams of quartz extend a little way up 
 into the Trias. These stringers contain galena which is gold-bear- 
 ing, also copper and iron pyrites; in fact, they have much the same 
 mineralization as the main lode itself. They do not reach the Lias. 
 The accompanying sketch (Fig. 1) illustrates these conditions. 
 
 * "Quartz enfume, tfun bleu noirdtrc." f Journal des Mines, 1806. 
 
LA GARDETTE : THE HISTORY OF A FRENCH GOLD MIXE. 5 
 
 The Trias is a metalliferous horizon containing a notable pro- 
 portion of iron pyrites, usually in fine grains, arranged in small 
 seams, which ramify through the mass of the formation. 
 
 The lode of La Gardette answers to the term, much misused, 
 and often but little understood, " true fissure- vein." In this in- 
 stance we have a " gold-quartz-vein," and it is necessary to recog- 
 nize separately each one of the words which make up the name. 
 In practice it is too little recognized that a vein may (as "true 
 fissure-veins " are popularly supposed to do) continue indefinitely 
 downward through the crust of the earth, but unless it carries gold- 
 Fig, i. 
 
 CROSS-SECTION SHOWING 
 RELATIONS OF LA GARDETTE LODE. 
 
 quartz it is commercially of no value, however interesting scientifi- 
 cally it may be. Further, the gold-quartz may be continuous, but 
 unless the precious metal is present in a certain proportion it ceases 
 to be valuable to the miner. Here at La Gardette we have a very 
 beautiful* specimen of this type of ore-deposit; and in attempting 
 to arrive at its probable history it is necessary to distinguish between 
 the vein and the lode, between the fissure and the mineral matter 
 deposited in or along that fissure. 
 
 It is evident that the vein is anterior to the deposition of the 
 
 * By reason of its striking regularity of structure. 
 
6 LA GARDETTE: THE HISTORY OF A FRENCH GOLD MINE. 
 
 Trias, and consequently much older than the Lias. The two vein- 
 lets which start from the upper edge of the vein and penetrate the 
 Trias owe their origin to movements which caused fractures to be 
 formed in the Trias, and at this point are in line with the course of 
 the main fissure, because the latter was a line of least resistance. 
 
 The fact that the mineralization of the veinlets in the Trias is 
 identical with that of the upper part of the main lode in the gneiss 
 points to a common origin. It appears to me, therefore, that while 
 the formation of the fissure of La Gardette, as well as the deposi- 
 tion of the quartz of the lode, antedated the laying down of the 
 beds of the Trias, it was, notwithstanding, from the overlying Trias 
 that the lode, in common with these veinlets, may have derived a 
 certain portion of its metalliferous contents. 
 
 When the gneiss was eroded during the period preceding the 
 deposition of the Trias, the lode-cropping was also denuded, with 
 a resulting natural concentration along the apex of the vein. In 
 later times, after the Trias period, further mineralization took place 
 to an extent not now ascertainable. The practical result was that 
 that portion of the lode which was immediately under the Trias was 
 enriched, and that this part of the vein became really the only com- 
 mercially valuable part of it. 
 
 Upon the fact just stated hinges the whole history of the mine. 
 The gold first discovered was in the capping immediately under the 
 dolomite cliffs of the Trias, where the original cap of the lode had 
 been laid bare, as in the times before it was covered by the sedi- 
 ments of the Triassic seas. This part of the mine was very rich in 
 pockets of free gold, and soon became exhausted. Afterwards, when 
 capital had been obtained, the engineers who had charge of the 
 spending of it directed their attention to the deeper parts; their con- 
 fidence of increased richness with depth augmenting in proportion 
 as they recognized that the upper parts of the mine were becoming 
 exhausted.* 
 
 Successive administrations essayed and failed to open up a pro- 
 ductive mine at lower levels ; while, during the intervals, the peasants 
 scratched about in the upper workings and found occasional speci- 
 mens. 
 
 To-day the history of the development of the mine can be read in 
 the underground workings. Owing to the comparative smallness 
 
 * Many of the reports of the French engineers declare that increasing richness 
 may be expected with increasing depth. This is a fallacy too frequently repeated 
 in later times by men who have seen far more of gold-mining. 
 
LA GAKDETTE : THE HISTORY OF A FRENCH GOLD MINE. 7 
 
 of the lode, its great regularity and the hardness of the enclosing 
 rock, the workings are all readily accessible. The upper develop- 
 ment consists of adits alone ; the lower, of shafts connecting a series 
 of levels. The total vertical depth explored exceeds 400 feet. It 
 is seen that while all the quartz has been stoped away from the first 
 level up to the sloping floor of the gneiss-dolomite contact above, 
 and a winze follows that contact for a short distance under the 
 level,* in the lower workings, on the other hand, hundreds of feet 
 of drifts have been extended without the stoping of a fathom of 
 ground. In the uppermost part of the lode the quartz is bluish and 
 ribboned, containing galena and pyrites ; but lower down, while it 
 still carries occasional patches of pyrites, it is white and barren. The 
 upper portions of the lode have a width of 20 to 25 centimeters, but 
 in the lower levels this is increased to 30 and 40; above, it is com- 
 pact ; below, it is full of geodes lined with crystals. While the upper 
 part has been a gold-mine, the lower part has been, and is still to-day, 
 valuablef for rock-crystals alone. Assays made by me of the 
 quartz standing in the lower level gave traces of gold only. 
 
 The vein is remarkable for the extreme development of two 
 features common to many gold mines slickensides and ribbon- 
 structure. 
 
 The slickensidesj extend continuously over large portions of the 
 surface of the wells, for a length of 400 meters and a height of 
 over 80. The striae are nearly horizontal, an evidence of a very 
 i*eat change of position, indicating a movement through a large 
 angle. That this is not impossible, or indeed improbable, is 
 shown by the evidence of similar movements to be found in the 
 vicinity ; at Allemont, for instance. This change of position was 
 probably contemporaneous with the period of the contortion of the 
 schists (or gneiss); and both were in all likelihood due to the up- 
 lifting action of the granite, a boss of which peeps from under the 
 limestones of the Grandes Rousses. 
 
 The very beautiful lamination or ribbon-structure which charac- 
 terizes the vein has received frequent mention from visitors. M. 
 Charles Levy records that in one band alone, 9 centimeters thick, 
 
 * This has much to remind one of the "contact " and " verticals " in which the 
 ore occurs at Rico, Colorado. 
 
 f M. Napoleon Albertas, who kindly guided me over the mine, exploits the lower 
 workings for the rock-crystals found there, and'has lately shipped groups to Paris 
 which brought him 600 to 1000 francs per lot. 
 
 bv the French and "harnische" bv the Saxons. 
 
8 LA GARDETTE: THE HISTORY OF A FRENCH GOLD MINE. 
 
 he counted 38 laminae or ribbons. To some of those who have de- 
 scribed the mine, it has suggested successive reopenings and fillings 
 by crystallization. To others, it has indicated merely intermittent 
 crystallization. 
 
 This structure of gold-quartz- veins, frequently observed in 
 widely separated mining districts, is generally recognized by miners 
 as a favorable indication. Allied to it is the observation that milk- 
 white quartz is usually less likely to be gold-bearing than that 
 which has a dark or bluish tinge. 
 
 The explanation of the ribbon-structure does not require the 
 fanciful imaginings of the "successive reopening and refilling'' 7 
 theory. That the lode is usually an altered form of the country 
 which the gold-vein traverses, is a fact now generally recognized. 
 All underground observation leads one to look upon the dark, 
 nearly parallel lines which cause the ribboning as the last remnants 
 of included fragments of country-rock. In the gold-mines of Cali- 
 fornia and Australia, one can frequently note the transition from the 
 large, irregular pieces broken from the lode-walls to the small, more 
 regularly arranged fragments which serve to subdivide the width of 
 a lode. In certain cases one may follow the slow gradation from 
 quartz filled with portions of "country" to dark quartz in which 
 the traces of included country are entirely unrecognizable.* At La 
 Gardette it is to be noted (the fact is recorded by M. Graff) that 
 when the vein includes fragments of the inclosing country, such in- 
 clusions are always smaller than the width of the particular band of 
 quartz in which they are arranged. 
 
 It is not possible to imagine that, under ordinary circumstances, a 
 cavity could long remain empty under the weight of the overlying 
 rocks. Any fracture or fissure formed must immediately tend to 
 close up, and where it is a line of movement, a fault, as many veins 
 are, the effect would be to choke it up with fragments torn from that 
 wall which was of inferior hardness. Later movements along the 
 same line would tend to shear off additional portions of the enclos- 
 ing country. Further, it has been shown (by Becker at the Corn- 
 stock, for instance), that the action of a fault is to cause a sheeting 
 of the country by fractures in sympathy with the main line of 
 fault. This structural effect might also come into play within a lode ; 
 for, as the mineral solutions percolating along the main fissure or 
 
 * In Australia this would be the transition from "rnullocky" to " mottled 
 quartz. 
 
LA GARDETTE: THE HISTORY OF A FHEXCH GOLD MINE. 9 
 
 line of fracture dissolved portions of the included broken country 
 and in turn deposited quartz or other lode-filling, they would also 
 follow the other lines of fracture lying latent in the adjoining coun- 
 try. The result would be one of those cases where one or more 
 " false walls" are found, and where it is only the proportion of gold 
 present which determines where the lode may be practically con- 
 sidered to cease.* 
 
 In thus insensibly passing from a discussion of ribbon-structure 
 to that of lode-walls I have but followed the transition which occurs 
 underground. But to return: When the lode filling is less hard 
 than the enclosing country, there is always a likelihood of its be- 
 coming the line of movements similar to those which brought it 
 into existence. Later faulting would take place along the lines of 
 included country rather than along that of the hard quartz, and 
 would result in the crushing of those portions of included country 
 and their arrangement along parallel lines. Occasionally the in- 
 cluded country is harder than the portions of the vein more or less 
 incompletely filled with quartz, and then we get the crushed sugar- 
 like quartz which characterizes several well-known lodes. 
 
 Experience shows that ribbon-structure is a desirable feature of a 
 gold-vein. In the mines of California and Australia these black 
 lines of lamination greatly facilitate the actual breaking of the 
 quartz ; but besides this they are generally found to characterize 
 gold-bearing rock. This fact, common to districts otherwise very 
 dissimilar, is something more than a coincidence. These black lines 
 are often graphitic, f the evidence left by metamorphism of the or- 
 ganic remains deposited in the original sedimentary rocks. Such 
 carbonaceous matter would act as a reducing agent upon mineral 
 solutions, leading to the precipitation, for instance, of gold from a 
 chloride solution. In some of the mines of Victoria, the thin, black 
 seams of slate dividing the quartz are found to be covered with a 
 mosaic of fine gold. In California similar instances are not un- 
 known. 
 
 In this connection, one is reminded of the fact that dark and 
 bluish quartz are found by experience more likely to be gold-bearing 
 than white quartz. There is a distinction to be made, however, be- 
 
 * It is a bad tendency which some miners have, to seek for " walls," and then, 
 having found one, to desist from any further cross-cutting through the lode. 
 
 f The miners of Amador county, California, when they come up from under- 
 ground, look like coal miners, on account of the black slate having discolored their 
 clothes. 
 
10 LA GARDETTE: THE HISTORY OF A FRENCH GOLD MINE. 
 
 tvveen the dark and the bluish-tinted varieties; for while the former 
 appearance is probably due to the presence of minute fragments of 
 black slate or other country-rock, now almost entirely replaced by 
 quartz, the latter is due to the presence of sulphate of iron, which 
 may be either original or a secondary result of the decomposition 
 of iron pyrites. Such quartz becomes rusty by oxidation within 
 the zone of surface-decomposition. In this case, ferrous sulphate 
 may play the part of the graphitic matter of the black slate. 
 
 In leaving the subject it is well to add that, in mining, generali- 
 zations are always dangerous if followed too far. An instance is 
 suggested by the above paragraph. White or dull whitish quartz is 
 invariably considered by the California miner an evidence of the 
 poverty of the vein ; and yet I have seen at Bendigo quartz of this 
 character, at a depth of over 2000 feet, which carried gold freely, not 
 in an isolated pocket, but as characterizing a lode-formation over a 
 great distance. 
 
 NOTE BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other errors, 
 or communications for publication as " Discussion," or independent 
 papers on the same or a related subject, are earnestly invited. 
 
Subject to Pevision. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 THE MINES OF THE CHALANCHE8, FEANCE. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Bridgeport Meeting, October, 1894.) 
 
 IN southeastern France, among the magnificent alpine masses of 
 the Dauphine", there is a group of celebrated mines of silver-, 
 nickel- and cobalt- ores, the deposits of which present many features 
 of interest. In 1891 I directed the work done at the Chalanches, 
 and at that time made the notes upon which the present paper is 
 based. 
 
 The workings consist of a complex series of adit-levels entering 
 the heart of a mountain, the summit of which is one of the lower 
 peaks of the Belledonne, in the commune of Allemont, and over- 
 looking the valley of the Romanche and its tributary, the Eau 
 d'Olle. The lower adits are 3700 feet above the village of Alle- 
 mont, or 7250 feet above sea-level. 
 
 HISTORICAL. 
 
 The discovery of these, as of many other notable mines, was acci- 
 dental. In 1767, JVIarie Payen, a shepherdess (bergere) of Alle- 
 mont, found an outcrop of silver-ore, and brought away, in ignorant 
 curiosity, a lump of heavy stone, which she handed to the village 
 smith. When tested on his forge, the molten silver trickled from 
 it. The shepherdess received 600 francs upon her wedding-day as 
 a reward for the discovery.* Thereupon some of the peasants of the 
 commune began to dig and to smelt the silver-chloride ores, the 
 croppings of which they traced down the mountain-side. The ex- 
 ploitation thus inaugurated continued with but little interruption 
 for more than a century. 
 
 The first mining done was digging, f A loss of life through a 
 crush in the excavations caused the authorities at Grenoble to take 
 
 * There is an entry on the pay-sheet for September, 1768, made in the hand- 
 writing of M. Schreiber. *' Paid to bergere Marie Payen, at her marriage with Jean 
 Roux, master charcoal-burner at ihefonderie d' Allemont, the sum of 600 livres as 
 recompense for discovery of the mine." 
 
 f '* Gophering " or " coyoting." 
 
2 THE MINES OF THE CHALANCHES, FRANCE. 
 
 official cognizance of these operations ; and M. Lemonnier, a mem- 
 ber of the Academy of Sciences, was sent by order of the king to 
 investigate the discoveries of silver reported to have been made by 
 the peasants. 
 
 In 1769, systematic work was commenced under the direction of 
 a Piedmontese engineer, M. Binelli.* 
 
 On the 10th of June, 1776, the king granted a concession of these 
 mines, as well as those of Allemont and La Gardette,f to his brother, 
 the Comte de Provence, afterwards Louis XVIII. Smelting-fur- 
 naces were erected at the base of the mountain near Allemont. 
 
 In 1781, Binelli gave place to Schreiber, who assumed the direc- 
 tion of the smelting establishment and of the various mines. Sehrei- 
 ber's name is interwoven with the history of most of the mines in 
 this part of Europe. He was a Saxon engineer of much ability, and 
 was the father of the ficole des Mines, which was first established at 
 Moutiers in Savoy. 
 
 On the 2d of August, 1792, as a consequence of the Revolution, 
 the mines became national, and passed into the hands of the new 
 government. 
 
 The >ears intervening between 1776 and 1791 cover the most 
 prosperous period in the history of the mines. In 1791, the amount 
 of development- work was decreased, and the profits dwindled away 
 under bad administration. The silver produced was sent away, but 
 the amount of money necessary to pay for the work was not for- 
 warded to the mines. Accounts were liquidated with billets or 
 promissory notes instead of cash. Matters went slowly from bad to 
 worse until 1807, when the State abandoned operations and made a 
 concession of the mines to a public company. 
 
 From the first discovery up to 1801, a period of thirty-two years, 
 the mines produced 9453 kilos, or 303,514 Troy ounces of silver. 
 According to Schreiber, the receipts were 2,098,421 francs, or 65,577 
 francs per annum. The expenses, 1,890,056 francs, equal to 59,090 
 francs per annum. During this period there were times when the 
 lodes became very much impoverished, and the profits were further 
 diminished by the erection of reduction- works, buildings and other 
 outlays. There remained, nevertheless, a net balance of 207,585 
 
 * For many of these data I am indebted to an Extrait des Memoires de la Societe 
 des Ingenieurs Civils by M. Alfred Caillaux. 
 
 f See "La Gardette : The History of a French Gold-Mine," by the writer. 
 Trans., vol. xxi., p. 79. 
 
THE MINES OF THE CHALANCHES, FRANCE. 
 
 francs. The best years were 1784 and 1785, when the profits 
 amounted to 55,000 and 54,000 francs respectively. 
 
 In 1808, Schreiber became director of the jficole des Mines at 
 Moutiers,* and ceased to manage the Chalanches. In 1809, a new 
 company obtained control of the mines through an imperial decree. 
 It was short-lived, and was succeeded by a series of other compa- 
 nies, which did more or less work iu an unsystematic manner up 
 to 1873. In 1889, application was made by Pierre Manin for a 
 concession of the then abandoned mines, A company, La Societe 
 Savoy sienne,^ was formed to operate mines in Savoy and in the 
 Dauphine, including those of the Chalanches. This ambitious enter- 
 prise exhausted its energy in making large promises, and, after a brief 
 existence, was sold out for the benefit of its creditors. The Countess 
 de Grail ly became proprietress of the Chalanches, and of Grand 
 Clos, the mines of which have always been worked in conjunction 
 with the former. 
 
 In 1890 the mines passed into the hands of an English Company, 
 the " French Mines, Ltd.," and vigorous work was commenced at 
 the Chalanches, as well as at Les Arabes, Villaret and Grand Clos. 
 Owing to the fact that the other mines of this extensive group 
 offered better inducements for the investment of capital in their de- 
 velopment, the Chalanches was operated to a limited extent only. 
 The exploratory work led to the discovery of several rich pockets of 
 silver-ore and small patches of nickel- and cobalt-ores. On the 
 whole, however, the results were not such as to encourage further 
 work, and in September, 1891, operations ceased. These interesting 
 old mines are therefore again abandoned. 
 
 Resume of the History of the Mines. The record of the Chalan- 
 ches presents a story similar to that which is told of mines in more 
 modern mining districts. The inaccessibility of the mines in winter, 
 the richness of the ore, its great fusibility and the consequent sys- 
 tematic robbery of the silver are local commonplaces. Circumstan- 
 ces all worked together to make the Chalanches mines the prey of 
 the most barefaced plunder. With the aid of a common forge-fire, 
 even without the intervention of a crucible, and with little knowl- 
 
 * Sometimes spoken of as the " Ecole des Mines de Pesey." The mines of Pesey 
 and Macot, in the hills of old Savoy, were the cause of the choice of Moutiers, the 
 nearest town, as the locality for the first school of mines. 
 
 f That Gallic imagination by no means falls short of the Anglo-Saxon faculty 
 when it is applied to prospectus-making, is proved by the flamboyant style in 
 which the promoters of the^oci&e Savoysienne addressed the public. 
 
4 THE MINES OF THE CHALANCHES, FRANCE. 
 
 edge or skill, lumps of silver could be produced from the very rich 
 chlorides, ruby silver and black sulphides which constituted in the 
 main the soft earthy ores or terres found in the crevices of the out- 
 crop. Aged inhabitants still talk sportively of the theft like old 
 smugglers, and point out nooks in the woods which the remaining 
 ruins of the little furnaces dug out by the miners, show to have been 
 the scenes of former illicit silver-ore smelting. In these furnaces, 
 no larger than an ordinary fire-place, dug in the earth and smeared 
 with clay, with charcoal, or, failing that, clods of dung for fuel, and 
 two or three little urchins to blow, like cherubs on the old maps, 
 out trickled the white metal. Clergy and people joined cheerfully 
 in these moonlighting operations without in any degree shocking 
 local ethics. The priest at Allemont, who lately restored the parish 
 church, says that the old church had a room adjoining the sacristry, 
 in which a former reverend father used to melt down the silver-ore 
 brought to him by the faithful. The slags were concealed in an ex- 
 cavation under the floor, where a large accumulation of them was 
 found when the church was restored. 
 
 During the earliest period of mining at the Chalanches, some 
 bodies of extremely rich ore were found near the surface. It is 
 said* that two shots produced sufficient silver to pay for the two 
 buildings known as the pavilions at Allemont, with their various 
 ornamentations, including the fleurs-de-lis which still adorn the roof. 
 As 200 to 300 kilos of silver would at that time be worth from 
 $10,000 to $15,000, this statement does not seem incredible, f 
 
 A " pockety " mine is notoriously apt to be loosely and extrava- 
 gantly managed. The uncertainty of the work is prejudicial to the 
 maintenance of system. The various companies that operated these 
 mines from 1808 to 1873, did so at a loss, due largely to inexperi- 
 enced engineering and loose financial management. 
 
 M. Geymard, an engineer of repute, says of this interval of sixty- 
 five years : 
 
 "Explored, exploited, abandoned and resumed by new companies, the mine paid 
 dividends or levied assessments according to the ability of the men sent to take charge 
 
 * For this information, and many notes, I am indebted to my father, Mr. Thomas 
 Rickard. 
 
 f An idea of the value of the ore, outside the patches of extremely rich mate- 
 tial, may be gathered from a statement made by M. Schreiber, in a report sent to 
 the Academic and afterwards reproduced in the Annales des Mines, that the average 
 richness of the Chalanches ore treated in the furnaces at Allemont, up to that time, 
 was 750 grammes per 100 kilos, equivalent to about 219 Troy ounces per ton of 
 2000 pounds avoirdupois. 
 
THE MINES OF THE CHALANCHES, FRANCE. 5 
 
 of the works and according to the amount of the capital placed at their disposal. 
 To sum up, the mining was restricted to the workings opened up by Schreiber ; for 
 all his successors confined themselves to a few meters of development and explora- 
 tion among the old drifts." 
 
 M. Caillaux, summarizing the history of this period, adds : 
 
 " The mines of the Chalanches were never worked on a proper scale during the 
 present century and, as has been well expressed by M. Gruner, the want of success 
 marking the various attempts made during this lapse of time does not in any way 
 prove the sterility of the ore-deposits, or the impossibility of its being operated to 
 advantage." 
 
 The latter part of this statement is open to discussion. 
 
 It is not a little remarkable that although the silver is always 
 associated in the lodes with rich nickel- and cobalt-ores, often with 
 bunches of stibnite, and more rarely and erratically with gold, the 
 government engineers took no note of any metal other than silver. 
 None of the valuable metals mentioned figure in the old accounts. 
 The speiss containing nickel and cobalt was rejected with the slags, 
 and went to fill the swamps and to form the road-beds which, in 
 later times, were furrowed and turned over to recover their valuable 
 contents.* 
 
 The possibility of utilizing three metals instead of one seems to 
 
 * It has not been found possible to ascertain the value of the old mattes with 
 which roads were made and marshes filled, but the following notes will assist : 
 Herr O. F. Kotttg, writing from Oberschlema, August 7, 1889, with regard to the 
 speiss, picked up in the old smelter-dump and shipped by Pierre Manin, says that 
 it contained 3.6 per cent, metallic cobalt, 8.9 per cent, metallic nickel, and 0.2 per 
 cent, silver. Another lot gave 3 Co, 11.8 Ni, and 0.3 Ag. This speiss was neglected 
 during Schreiber's time. 
 
 In August, 1863, the Viscount de Talon sent 7 barrels of ore to Vivian & Sons, 
 Swansea. The ore in these barrels ranged in value (net) from 3 to 31 per ton, 
 not including the silver. The average was about 16. The nickel was valued at 
 Is. 9c?. per pound, the cobalt at 7s. per pound. The smelting charge was 1.10.0 
 per ton. The contents of the barrels were : 
 
 No. 
 
 1, . . . 
 
 2,. . . 
 
 2,. . . 
 
 3,. . . 
 
 4,. . . 
 5, . 
 
 5, . . , 
 
 6, . -. ; . 
 7,. . . 
 
 
 
 
 Nickel. 
 
 Cobalt. 
 
 Silver. 
 
 Cwt. 
 
 Qr. 
 
 Lbs. 
 
 Per cent. 
 
 Per cent. 
 
 Oz. per ton. 
 
 16 
 
 
 
 9 
 
 .6 
 
 .07 
 
 11 
 
 2 
 
 
 
 6 
 
 2.6 
 
 1.30 
 
 47 
 
 3 
 
 
 
 6 
 
 1.1 
 
 0.60 
 
 19 
 
 6 
 
 
 
 10 
 
 3.2 
 
 2.00 
 
 81 
 
 17 
 
 3 
 
 26 
 
 3.0 
 
 1.60 
 
 201 
 
 1 
 
 
 
 8 
 
 2.3 
 
 1.6 
 
 86 
 
 3 
 
 
 
 7 
 
 3.8 
 
 1.9 
 
 192 
 
 23 
 
 3 
 
 9 
 
 3.2 
 
 1.9 
 
 27 
 
 1 
 
 1 
 
 8 
 
 4.3 
 
 3.3 
 
 39 
 
6 THE MINES OF THE CHALANCHES, FRANCE. 
 
 have dawned upon the later engineers quite as a discovery ; and this 
 fact stimulated the repeated spasmodic attempts to rehabilitate 
 the old mine. The arsenides of nickel and cobalt were sold in 
 England and in Germany.* More recently, a German chemist was 
 employed at Allernont in an experiment to manufacture cobalt 
 pigments for the arts. He was not successful, and the attempt 
 was abandoned. 
 
 In 1891 the gold-value was first recognized. f Its importance 
 proved greater from a scientific than from a commercial point of 
 view. The old mine- workings, aggregating 20 kilometers in length, 
 showed that a great deal of unsuccessful exploration had been car- 
 ried out. Search among these galleries, particularly near the sur- 
 face, resulted in the finding of certain rich bunches of ore, which 
 were soon exhausted. An attempt to introduce the tribute- or lease- 
 system was made, with partial success. The necessity for concen- 
 trating the operations of the company led to more active work at 
 Grand Clos and Les Arabes, and, at the same time, made it advisable 
 to abandon the Chalanches. 
 
 THE ORE-DEPOSITS. 
 
 The geological formation is simple. A network of veins traverses 
 crystalline schists of very variable character. The country forms a 
 part of the great crystalline formation usually referred to as the 
 Archaic schists of the Alps, though in point of fact they probably 
 include rocks from the granite up to the Carboniferous. Lithologi- 
 cally, certain sections suggest the Huronian and Laurentian. These 
 schists lie immediately upon the granite; they are extremely varia- 
 ble in character, so that at different places they can be described as 
 
 * The Chalanches mines were always worked in conjunction with those of Grand 
 Clos, near La Grave. The lead-ores of the latter were brought about 20 miles to 
 Allemont, to be smelted with the products of the Chalanches. The smelting 
 was simple. The lead-sulphides and the arsenides of nickel and cobalt were 
 submitted to stall-roasting, and then passed through a low blast-furnace (four d 
 manche), giving as products: (a) work-lead, containing the silver, and, of course, 
 the gold, if present; (6) speiss, containing the nickel and cobalt; (c) slags. The 
 work-lead went in succession to Pattinsonage and cupellation for the extraction of 
 the silver. The speiss and slag went over the dump. It was only in later years 
 that the nickel and cobalt were taken account of. 
 
 f Small samples of the earthy ore gave occasionally as much as 1 to 1^ ounces 
 per ton. At Les Arabes, a mine just above the village of Allemont, there occurred 
 narrow streaks of maroon -colored earthy stuff, which assayed from 2 to as high as 
 
 7 ounces of gold per ton. 
 
THE MINES OF THE CHALANCHES, FRANCE. 7 
 
 gneissose, granitoid, talcose, micaceous, graphitic, or amphibolic.* 
 At the base of the slope leading to the mines there are superb blocks 
 of rock, containing crystalline epidote. 
 
 Chalanches, like the mines of the Alps generally, in France, in 
 Savoy, or in Switzerland, is far up toward the summit of the com- 
 plicated schist-region. Looking across the valley of the lovely 
 Romanche, one can see La Gardette, the historic gold-mine of 
 France, perched upon the cliffs overlooking Bourg d'Oisans. Across 
 the winding Eau d'Olle rises the imposing mass of mountains known 
 as "les Grandes Rousses."f One can distinguish their structure, 
 which more immediate examination proves to be that of crystalline 
 schist overlain patch-wise by the dolomite of the Trias, in turn 
 succeeded by the shales and slates of the Lias. 
 
 Immediately above the Chalanches mines and in rocks of Car- 
 boniferous age there is a deposit of anthracite. To the anthracite 
 succeeds, in fragmentary deposits, the dolomite limestone, which, 
 though less constant than the Carboniferous sandstone and shale, 
 almost always accompanies the anthracite basins, and in the Hautes 
 AlpesJ is associated with what appears to be Permian sandstone 
 and the gris bigarre. The latter fact gives rise to the suggestion 
 that the dolomite belongs rather to the Permian than to the Trias. 
 
 The country which more immediately holds the lode-channel of 
 the Chalanches mines, and which I may term the encasing rock, has 
 the character of gneiss. In actual contact with the veins it is amphi- 
 bolic and contains a notable amount of pyrite. This last character- 
 istic causes it to emit sparks when struck with steel and indicates the 
 origin of its local name, la roche martiale. 
 
 The oxidation of the pyrite is the reason of the red bands which 
 seam the steep bluff crowning the upper precipitous summit of the 
 mountain. These bands of pyritic schist dip into the hill just as 
 the main series of veins does, a fact which led M. Graff, a distin- 
 
 * On the government map the whole mass of the Chalanches, as also the Cor- 
 neillion, on the opposite side of the river, is marked " amphibolites." Above and 
 beyond Chalanches, there is shown a peak of " euphotide amphibolique," flanked 
 by serpentine. There is no doubt that these rocks, on either side of the Romanche, 
 are in places highly amphibolic, but it is an error to describe the entire mass ot 
 the mountain as such. 
 
 f I.e., the great " roughs," ruffians, or rugged ones. 
 
 At Argentiere and Valgaudemar. 
 
 $ The gres bigai-re is the Bunter sandstone of the Vosges, where it rests com- 
 formably on the red Permian sandstone. (See Geikie's Textbook of Geology, 3d ed., 
 p. 870.) 
 
8 THE MINES OF THE CHALANCHES, FRANCE. 
 
 guished engineer, to conclude that they played the part attributed 
 to the fahlbands of Kongsberg, in Norway. 
 
 The maps of the mine exhibit a wonderful network of galleries, 
 spreading like a cobweb over an area of about 600 by 300 meters. 
 
 It is computed that the workings aggregate in length not less than 
 12 miles, an extent in remarkable contrast to the relatively small 
 quantity of ore produced. 
 
 The principal veins are six in number, four of which, the Cobalt, 
 Prince, Simeon and Hercule, lying about 15 meters apart, dip rather 
 flatly into the mountain, in conformity with the bedding of the en- 
 closing rock-formation, while the two others, the Directoire, a nearly 
 
 Fig. I. 
 
 Cross-Section, Showing the Veins of the Chalanches. 
 
 vertical vein, and the St. Louis, which cuts it diagonally, may be 
 considered as cross- veins or counter-lodes to the main-series. The 
 accompanying cross-section (Fig. 1) will explain these relations. 
 
 In addition to the six lodes mentioned there are several minor 
 veins which may be considered as branches or feeders of the main 
 series, the whole forming a complicated web of ore-bearing fissures, 
 Schreiber is quoted as having said that " the veins have as many 
 directions as there are points of the compass." Gruner speaks of 
 Chalanches as " a mountain radiated and fractured in every direc- 
 
FRANCE. 9 
 
 tion, the largest fissures being filled with fragments of the encasing 
 rock and the smaller fissures with metalliferous ores of very varied 
 character. " Geymard considered the lode-structure to be a stockwerk; 
 but Graff distinguished two principal groups of veins, namely (1) 
 those which have a north-south strike and dipped either east or west, 
 apparently parallel to the lamination of the encasing schist, and (2) 
 those which strike east-west and dip uniformly to the north. Ac- 
 cording to the same authority, the veins north-south were the most 
 regular and continuous. Both series, however, were stated to throw 
 off numerous branches and thus gave rise to an apparently inex- 
 tricable confusion. 
 
 Of the engineers quoted, Graff was the most trustworthy observer. 
 His description of the veins is good. Others, even Schreiber, seem 
 to have entirely failed in mastering the difficulties of the deposit. 
 In the more fissured ground near the surface the lode-formation may 
 bear the description of a stockwerk, or, more properly, little sep- 
 arated patches of stockwerk; but in depth this character is not ap- 
 parent. Observation at every point at which the numerous veins 
 occur along the southeastern flanks of the Belledonne massif goes to 
 prove that by far the greater number of the veins which have been 
 mined conform to the bedding and, therefore, dip into the hill, as 
 the Chalanches lodes do. They follow the flexures and folds of the 
 schist, and naturally present all kinds of variations of direction 
 when exposed in the mine workings. This is also observable at 
 Les Arabes, Villaret and Oulles. The cross-lodes appear to be rela- 
 tively unproductive, the St. Louis and Directoire being exceptions. 
 It may be said, speaking generally, that these bedded veins in the 
 Dauphine* are weak, inconstant and difficult to follow. f They are 
 frequently altogether obliterated, leaving to the miner the bedding 
 of the country as his only guide. Hence the apparent extravagance 
 of drifts. 
 
 Towards the center of the mine workings of the Chalanches there 
 are three dikes of diabase, respectively 23, 3 and 30 meters in thick- 
 ness. Furthermore, all those who have at various periods directed 
 the mines take note of large barren fissures which traverse the 
 mountain and dislocate the ore-bearing veins. They are filled with 
 fragments of country and with clay, both sandy and micaceous. 
 Schreiber considered them as barren lodes and termed them " filons 
 
 * The more modern departments of the Isere and Hautes Alpes. 
 t These bedded veins in the schists remind one often of the lodes in the quartzose 
 schists of Otago. (See Trans., xxi., 411 et seq.) 
 
10 THE MINES OF THE CHALANCHES, FRANCE. 
 
 aauvages priv'es de substances m'etalliques" A Cornish man would 
 call them "flookan." 
 
 It has been thought by several observers that the lodes were more 
 numerous near the surface than in the interior of the mine. This is 
 due to the fact that any single fissure, in approaching the surface, 
 spreads itself out into a number of subordinate fractures. It has 
 also appeared that the lodes gained in regularity as they penetrated 
 the mountain. Caillaux therefore adds that this fact seems to indi- 
 cate the probable occurrence in depth of only a small number of 
 lodes, but that those surviving will have a regularity greater than 
 those which have been hitherto exploited. Regularity of structure 
 would be a poor compensation to the miner for the fact that the en- 
 closing rock is much harder, and the thickness of ore smaller, than 
 in the ground nearer to daylight. 
 
 The veins vary in width from a knife-blade to 80 centimeters (31.5 
 inches); their usual thickness lies between 3 and 30 centimeters 
 (0.1 to 1 foot). The following data from my note-book will indi- 
 cate, in a general way, the size and nature of the veins : 
 
 July 14, 1891. 
 
 Premiere Hercule. 12 cm. in two parts: the upper, quartz and 
 fine-grained galena ; the lower, efflorescence of nickel 
 (annabergite) in earthy ore. 
 
 Troisieme Hercule. 30 cm. Antimonial ore (stibnite and ox- 
 ide) accompanied by cobalt-bloom (erythrine). 
 
 Cinquieme Hercule. Vein crossed by cross-course. Broken ; 
 barren. 
 
 St. Nicholas. 35 cm. Brown earthy ore, containing arsenates 
 of nickel and cobalt, with native silver. 
 
 Galerie d' Argent. 5 to 7 cm. Wire silver, with black sul- 
 phides of silver, in an earthy gangue. 
 August 11, 1891. 
 
 Premiere Hercule. 10 cm. Chiefly calcite, a few spots of ga- 
 lena. 
 
 Troisieme Hercule. 35 cm. Calcite, with .threads of galena. 
 
 Prince. 20 cm. Red and black earthy ore (found afterwards 
 to contain 35 ozs. Ag) stained with copper. 
 
 Oinquieme Hercule. 7 to 10 cm. Calcspar, with splashes of 
 stibnite. 
 
 St. Nicholas. 12 cm. Black earthy ore, with stones of fahlerz 
 and kupfernickel. 
 
 Galerie d' Argent. 5 cm. Black earthy ore, full of native silver. 
 
THE MINES OF THE CHALANCHES, FRANCE. 11 
 
 General Conclusions Regarding the Ore- Occurrence. Some of the 
 conclusions of several accomplished French engineers have been 
 quoted. They differ according to the condition of the mine at vari- 
 ous periods, depending upon whether the development- work was 
 being vigorously pushed ahead, new ground opened up and rich ore 
 extracted, or whether the work of exploration was restricted and the 
 operations confined to the search for the pockets of silver which were 
 found from time to time i'rregularly distributed amid the complex of 
 veins. At the time when I directed the work, attention was mainly 
 confined to the exploration of blocks of ground not previously inter- 
 sected by drifts or cross-cuts. No work was done in the ends of 
 galleries farthest advanced into the mountain. My experience of 
 the mine and its ore-deposits led me to the following conclusions : 
 
 The formation of crystalline schists has been subjected to fissuring 
 at more than one epoch, an earlier one being marked by the fractures 
 filled with ore and now forming the lodes, and a later one charac- 
 terized by the formation of cross-fractures which broke across the 
 previously formed lodes, and are themselves non-metal-bearing. 
 
 Near the surface the lodes are soft, especially where they are 
 richest in silver. Though they agree in the main as to their mineral 
 impregnation, the daily advance of drifts will exhibit an extraordi- 
 nary variety of vein-filling. They all contain nickel, cobalt, silver, 
 and in places also antimony and gold, as their commercially valu- 
 able elements. With these are associated the numerous mineral 
 species for which the mines are famous, notably acicular crystals of 
 epidote. The minerals of the Chalanches are to be found in most 
 of the important collections of Europe.* 
 
 Examination of the old workings proves clearly that with increas- 
 ing distance from the surface the country gets harder, the veinstuff 
 loses its soft character, the veins become fewer in number, more reg- 
 ular, less wide and less ore-bearing. Approaching the surface, on 
 the contrary, the schists are fractured in a multiplicity of directions, 
 the veins become larger, their filling is generally earthy, and they 
 throw off branches, at the intersections of which ore-bodies are found. 
 In general, mineralization becomes more pronounced with approach 
 to daylight; this being due, not merely to the oxidation of the sul- 
 phides, but to an actual relative increase of " orey " matter. 
 
 The outer portion of the mountain is jointed and otherwise frac- 
 
 * Its contribution to the Museum of Natural History at Grenoble would itself re- 
 pay a % T oyage across the Atlantic. All the mines of Leadville, for instance, would 
 hardly furnish a richer collection of minerals than the Chalanches alone. 
 
12 
 
 THE MINES OF THE CHALANCHES, FRANCE. 
 
 tured to a very remarkable degree. The seams of ore which follow 
 such joints and fractures are often composed of earths rich in nickel 
 and cobalt, or of wire-silver mud. An illustration of such an occur- 
 rence is afforded by the pocket of native silver found within a few 
 
 Fig. 2. 
 
 Fig. 3. 
 
 Native Silver 
 
 Lamination of the Schists 
 
 Joints 
 
 Sections Showing Pocket of Native Silver. 
 
 feet of the surface, at the intersection of the St. Louis and Cobalt 
 veins, in July, 1891. The accompanying sketches, Figs. 2 and 3, 
 show the change in the lode-structure as the working progressed, the 
 time between the two drawings being four days. In Fig. 2 the 
 native silver, enclosed in a black mud, and accompanied by ochreous 
 
THE MINES OF THE CHALANCHES, FRANCE. 13 
 
 earth, extends from one vein, across the point of intersection, into 
 the other. In Fig. 3 the silver is confined to the upper part of the 
 Cobalt vein. Red iron-earth formed the filling of the St. Louis. 
 The structure of the enclosing country is merely suggested in the 
 drawings. 
 
 The observations made from day to day led me to conclude that 
 the richest part of the mine was that which was within the influence 
 of oxidation, and that both chemical agencies and structural condi- 
 tions favored an enrichment of ore near the surface. This statement 
 is particularly applicable to the silver contents. It also holds true 
 of the gold, but it is less accurate with respect to the nickel and co- 
 balt. The richness in silver of the oxidized ores suggests secondary 
 precipitation. This is confirmed by the fact that the silver appears 
 to be thrown down upon the nickel and cobalt arsenides, and often 
 envelopes them in such a way as to impart to them the rudiments 
 of a nodular structure. The hard, undecomposed arsenides con- 
 tain only small amounts of silver. The gold, only occasionally 
 present, is associated invariably with soft, maroon-colored, earthy, 
 iron-bearing vein-stuff. The nickel and cobalt minerals appear to 
 be primary ores, and are more persistent than those of silver and 
 gold. 
 
 The dependence of the occurrence of large amounts of rich ore 
 upon the broken and fractured character of the country would seem 
 to me to indicate that that particular concentration of metallic min- 
 erals which renders the deposit economically important is of com- 
 paratively recent geological date ; for, only near the surface (the sur- 
 face of any given time, not necessarily only that of to-day) were 
 there the conditions favoring such a concentration. A study of the 
 vein-structure of the surrounding region shows that the ore-bearing 
 veins are younger than the Jurassic age. This, of course, applies 
 only to the fissures in which the ore is now found. The actual de- 
 position of ore could not have commenced before the fracture took 
 place, but it has probably been going on ever since. At the Cha- 
 lanches, the change in the nature of the ore- deposits, both in struc- 
 ture and in mineral contents, is measured, not from any imaginary 
 nearly horizontal surface of a former unknown epoch, but from the 
 steep slope of the hillside of to-day. 
 
 The occurrence of deposits of nickel-ores in close association with 
 basic eruptives, and more particularly magnesian rocks, has been 
 frequently noted. The country-rock of the Chalanches lodes con- 
 sists of the crystalline magnesian schistose rocks, which have been 
 
14 THE MINES OF THE CHALANCHES, FRANCE. 
 
 already mentioned. They are overlain by doloraitic limestone, and 
 are intruded upon by a mass of altered gabbro or euphotide, which 
 is, in turn, flanked by serpentine. The serpentine may have been 
 derived by the metamorphism of amphibolic schists, euphotide, or 
 limestone.* That the origin of nickel-deposits is traceable to the 
 leaching of basic eruptives ; that the metal and its ores occur in 
 a finely disseminated condition in such rocks, and have been by 
 them brought within the reach of circulating waters, is, at present, 
 a strongly favored theory. f 
 
 As bearing on this part of the subject, the following additional 
 facts are pertinent. At the Chalanches, in addition to the magne- 
 sian silicate schists, forming the encasing rock of the lodes, there 
 are, at least, three dikes of diabase. Above Bourg d'Oisans six 
 miles distant there is an amygdaloidal paelaphyre (the spilite of the 
 French geologists), which carries nodules of calcite accompanied by 
 sulphide of nickel. J Between Allemont and Vizille there are, ac- 
 cording to the government map, several outcrops of spilite. They 
 are usually associated with the upper Trias, and occasionally appear 
 to belong to the Jurassic. Certain of the ore- bearing veins of the 
 district penetrate from the crystalline schists into the anthracite 
 beds, and even into the Lias, the last being the youngest formation 
 of the lode-mining portion of the region. 
 
 The roche martiale, or pyrites-bearing bands of schist, which im- 
 mediately contain the most productive veins, illustrate that associa- 
 tion of nickel and iron pyrites which has been often remarked by 
 geologists. 
 
 The origin of the metals which enrich the veins of the Chalan- 
 ches is a matter which, owing to the limited data bearing upon it, 
 cannot be discussed at great length with profit. The silver and 
 gold may be supposed to have been derived, as elsewhere, from as- 
 cending solutions which, in approaching the surface deposited their 
 precious contents according as the structural conditions of the rock 
 or the chemical composition of the casing of the fissures may have 
 regulated that deposition. The nickel and cobalt will be considered, 
 
 * That serpentine can be derived by metaraorphism from magnesian silicate 
 rocks, or from limestone, has often been pointed out quite recently by Mr. S. F. 
 Emmons, in "Geological Distribution of the Useful Metals," Trans., xxii., 71. 
 
 f It is advocated, for instance, by Mr. P. Argall, in a contribution to the Colo- 
 rado Scientific Society, entitled, " Nickel : the Occurrence, Geological Distribution, 
 and Genesis of its Ore-Deposits." 
 
 J A similar occurrence is that of millerite, or sulphide of nickel, recently noted 
 by me in certain hornblende-schists at the Gipsey Queen Mine, 3| miles east of 
 Salida, Colo. 
 
THE MINES OF THE CHALANCHES, FRANCE. 15 
 
 by many, to have had a more definite and immediate origin in the mag- 
 nesiau silicates of the diabase and schists, out of which they will be 
 supposed to have been leached. These explanations of the origin of 
 the four metals mentioned would, in that case, be a compromise be- 
 tween the contending views of the two sides in the controversy 
 between the extremes of lateral secretion and ascension. 
 
 It will be claimed, however, that, if the nickel and cobalt were 
 obtained fiom out of the encasing (the wall-rock), or the enclos- 
 ing (the remoter country) rock, then, there should be some differ- 
 ence in the schists penetrated by those parts of the lodes carry- 
 ing a notable amount of nickel and cobalt, as compared to the 
 schists in which the lodes are barren. It cannot be said that 
 this is the case. The bands of pyritic schist are parallel to the 
 lodes, and enclose both their rich and their barren portions. That 
 the lode-channel is marked by the presence of schist rich in pyrite 
 is true ; but the fact points not to the pyrite as the source of the 
 metal, but simply to a probable identity of source, and contempo- 
 raneity of deposition. Within the reach of oxidizing agencies, both 
 the nickel and cobalt arsenides and the iron pyrite are found 
 decomposed in some places, unaltered in others. The interior work- 
 ings of the mine show veins carrying hard unoxidized ores encased in 
 harder schists, the pyrite of which is unaltered. While the rock 
 which has been most affected by oxidation contains veins richer in 
 silver and gold than that which does not show the action of such 
 agencies, there is no noteworthy difference in the nickel- and cobalt- 
 contents. 
 
 In these mines, as in others in widely separated regions, I have 
 observed that it often happens that a very narrow but very rich 
 streak of ore may occur encased in hard undecomposed country, 
 while, on the contrary, a large width of poor veinstuff may be en- 
 closed by highly altered and mineralized rock. This, which is, I 
 believe, a common observation to those who spend much time under- 
 ground, is a fact forever opposed to the narrower* views of any 
 lateral-secretion theory. In such cases it is evident that the encas- 
 ing rock has been mineralized and enriched through the agency of 
 solutions which travelled in the lode-channel; that the mineraliza- 
 tion took place from the lodes to the country and not from the out- 
 side country toward the interior of the lode-channel. f 
 
 If we accept the current theory that the nickel and cobalt came 
 
 * As distinguished from the wider interpretation given to that theory, not by 
 Prof. Sandberger, but by Mr. Emmons and others in this country. 
 
 f This view was advocated by Mr. Pearce thirty years ago. (See Trans, xxii., 740. ) 
 
16 THE MINES OF THE CHALANCHES, FRANCE. 
 
 from the leaching of magnesian silicates (and facts are numerous 
 pointing that way), then, we must conclude that the origin of the 
 nickel and cobalt of the Chalanches was not the immediately enclos- 
 ing country, but rocks similar to it, which underlie it at a greater 
 depth. The silver and gold, it may be suggested, were precipitated 
 from other solutions, and at a period other than that which saw the 
 deposition of the nickel and cobalt. The precious metals were prob- 
 ably derived from a deeper-seated source ; and may have been 
 leached from the granite which underlies the schists and is penetrated 
 by the basic eruptives. In both cases, the various metals must have 
 come from a depth where leaching action was powerful, and from 
 which ascending currents brought the metallic constituents, the sub- 
 sequent precipitation of which produced valuable ore-deposits. 
 
 NOTE BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other errors 
 or communications for publication as " Discussion," or independent 
 papers on the same or a related subject, are earnestly invited. 
 
[TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Enterprise Mine, Rico, Colorado. 
 
 By T. A. BICKARD, STATE GEOLOGIST, DENVER, COLO. 
 (Colorado Meeting, September, 1896.) 
 
 I. HISTORICAL. 
 
 Rico, in the southwestern corner of Colorado, is one of the 
 productive mining centers of the San Juan region, so-called 
 because its waters drain into the river of that name, which is 
 tributary to the Colorado. The San Juan region includes the 
 counties of Ouray, Hinsdale, San Miguel, Dolores, San Juan 
 and Montezuma. It is traversed by a network of picturesque 
 mountain ranges on whose lofty summits there rests perpetual 
 snow. The region is peculiarly rugged, and, in the early days 
 of its development, tested to the full the hardihood of the ad- 
 venturers who first explored its canons in search for gold and 
 silver. 
 
 A prospecting party, guided by Jim Baker, scout and trap- 
 per, penetrated in 1861 this part of the territory of Kansas. At 
 that time the country was in the possession of the Ute Indians. 
 In October, 1873, by the Brunot treaty, they ceded to the United 
 States Government the richest mineral-bearing portion of their 
 domain. But in the interval much prospecting had already 
 been done, in defiance of difficulties among which snowslides 
 and redskins were the most noteworthy. The mountains bor- 
 dering the Animas and its tributaries were first explored by 
 the pioneers, but the gathering wave of immigration soon 
 swept further westward, and in 1864 a guide named Robert 
 Darling brought a party of United States army officers and 
 Mexicans from Santa Fe to the croppings of certain lodes 
 which he had found on the Dolores* river. This party erected 
 
 * If the Spaniard devastated the countries he conquered, he at least left a 
 poetic nomenclature in his wake. The river Animas was called Rio de las Ani- 
 mas perdidas "the river of lost souls," and the gloomy magnificence of its tu- 
 multuous way renders the name appropriate. Dolores, Durango, San Miguel, 
 San Juan, Ignacio, Dulce, Juniata, etc., compare well with Cripple Creek, Lead- 
 ville, Central City, Corkscrew, Coke Ovens, etc. 
 
 1 
 
THE ENTERPKISE MINE, RICO, COLORADO. 
 
 FIG. A. 
 
 400 800 IgQO 1600 
 
 Scale of Feet. 
 
 MAP SHOWING~THE PROPERTY 
 OF THE 
 
 ENTERPRISE MINING COMPANY 
 
 AT RICO, COLORADO. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 3 
 
 an adobe furnace and spent an entire summer in an abortive 
 attempt to smelt the ores, the outcrop of which can still be 
 seen at the north end of the main street of the town of Rico, 
 upon claims now owned by the Atlantic Cable Company. In 
 the autumn they returned to Santa Fe, and the valley was 
 given up to the trappers and hunters, who found beaver along 
 the stream and bear and deer on the hillsides. 
 
 In 1869 another expedition arrived. It consisted of John 
 Eckels, William Hill, Pony Whitmore and two others, all of 
 whom had made their way from the Moreno mines, a district 
 near Elisabethtown, in what is now New Mexico. They dis- 
 covered several large lodes near the site of the present settle- 
 ment of Dolores. In the following year, Gus Begole came 
 across the range from Silverton, and brought an assay-outfit 
 with him. He and his partner, Eckels, discovered and located 
 the Nigger Baby (now Yellow Jacket) and Dolores (now Aztec) 
 mines. They sank several shafts and ran several drifts, but the 
 ore proved too low in value to meet the costs of treatment and 
 transportation, and they abandoned their claims. Others, who 
 came from time to time, had a like experience. 
 
 In 1878, John Glasgow, Charles Hummiston and Sandy 
 Campbell found their way northward from La Plata City. 
 They spent the summer in active work, and located the Atlan- 
 tic Cable, Grand View, Phoenix, Yellow Jacket and other 
 claims. During the succeeding winter and in the early spring 
 of 1879, the news went out that " carbonates " had been found 
 at Rico, and a second Leadville uncovered. A " rush " set in. 
 In the fall of that year Messrs. Jones and Mackay, of Comstock 
 fame, visited the camp and purchased the Grand View group 
 of mines. Next year, 1880, the boom continued, and the erec- 
 tion of a smelter* was begun. The material required for con- 
 struction all came on mule-back over the ranges from Alamosa 
 at a cost of 16 cents per pound. In the fall the furnaces were 
 blown in under the superintendance of Messrs. Endlich and 
 Arnold. 
 
 All the early discoveries of this district centered around 
 Nigger Baby hill and the valley at its base. In 1879, however, 
 
 * That smelter still exists. It has afforded many well-known metallurgists 
 their early and hard-bought experience. Its history would present an amusing 
 commentary on the struggles of ill-digested enterprises. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 Fig. B. 
 
 LEGEND 
 
 Group Tunnel Level thus 
 Enterprise. Laura " 
 Intermediate 
 Contact .. 
 
 Limit of Contact Slopes 
 
 MAP OF THE 
 
 ENTERPRISE 3IINES 
 
 AND 
 
 WORKINGS. 
 
 E. W. Hunt, Surveyor. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 5 
 
 a shipment was made to Swansea from a discovery by Harry 
 Irving on a claim located further south, on Newman hill, which 
 is like a footstool to Mount Dolores. This event, unimportant 
 as it seemed at the time, marked the beginning of the devel- 
 opment which more than ten years later led to the prolific pro- 
 duction of gold and silver out of the workings of the Enter- 
 prise and Rico-Aspen mines. 
 
 In the spring of 1881 David Swickhimer, Patrick Cain and 
 John Gault sunk a shaft 35 feet deep upon their Enterprise 
 claim on Newman hill. This work was undertaken not upon 
 the evidence of ore, but in the expectation of cutting the con- 
 tinuation of the veins successfully worked in certain claims 
 further south, owned by the Swansea Gold and Silver Mining 
 Company. Without entering into a detailed description of the 
 geological structure of Newman hill it is necessary, in order 
 to make the early story of discovery clear to the reader, to say 
 that the true rock (sandstone and limestone) is overlain by 
 drift, through which shafts must penetrate before reaching the 
 ore-bearing formation. The veins do not reach the present 
 surface, save in the face of the landslip where Harry Irving 
 first detected them. The three owners above mentioned traded 
 their claim to George S. Barlow for $300 worth of lumber. 
 Barlow continued the sinking of the shaft to a depth of 146 
 feet. On an adjoining claim, named the Songbird, another miner, 
 A. A. Waggener, sank a shaft to the depth of 203 feet. The 
 latter penetrated through the drift into lime shale ; but the En- 
 terprise shaft did not at that time reach the true rock. Both 
 shafts got into very wet ground. In the meantime the Swansea 
 workings were reported to be impoverished and, finally, ex- 
 hausted of ore. It was also said that the veins did not extend 
 northward, but the real fact was that cross-veins had faulted 
 the ore-bearing veins in a manner to be rendered clear later on 
 in this account. Newman hill was discredited, and early in 
 1883 the Enterprise and Songbird shafts were abandoned. 
 
 A year later, Larned and Hackett resumed work in the 
 Swansea levels, and, by mere accident, discovered that the veins 
 had not come to an end, but were simply dislocated. They 
 prosecuted development, proved the continuity of the ore and 
 made large shipments. Their success induced Waggener and 
 Barlow to relocate their abandoned claims late in 1886. But 
 
6 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 neither of them had any capital, and they were unable to over- 
 come the heavy flow of water. In December, 1886, David 
 Swickhimer bought out Waggener's interest, acting on knowl- 
 edge obtained while working in the Swansea mine, which had 
 satisfied him that the veins must extend into the Enterprise and 
 Songbird claims. In March, 1887, he recommenced the sink- 
 ing of the Enterprise shaft. In May he acquired one-half of 
 Barlow's interest. In July the windlass was replaced with a 
 steam-engine and a pump. All this time Larned and Hackett 
 were drifting rapidly northward and threatened soon to reach 
 the boundary separating their territory from that of Swickimer 
 and Barlow. Unless the two latter succeeded soon in finding a 
 vein in place, so as to permit a valid location, the claims could 
 be successfully disputed.* They therefore hurried the sinking, 
 and in spite of bad luck, floods of water and a general lack of 
 experience, they struck ore on the 6th of October at a depth of 
 262 feet. The first assay gave 2.1 ounces of gold and 519.4 
 ounces of silver per ton. 
 
 This ore was one foot thick and formed part of a " flat lode." 
 In the light of later developments, this discovery is known to 
 have been a piece ot particular good fortune, for the maps of 
 to-day prove that it was the edge of the biggest ore-body ever 
 found on Newman hill, and that a shaft put down 20 feet fur- 
 ther east would have missed it. This was the first evidence of 
 the existence of a flat ore-deposit. Swickhimer thought at 
 first that it was merely a roll in the Enterprise, an almost 
 vertical vein. It was, however, soon proved by the workings 
 to be a bedded formation, conformable to the enclosing 
 
 7 O 
 
 country. The shaft was sunk 60 feet below this " con- 
 tact," and a drift was run westward until the increased seepage 
 of water, in the following spring, proved too much for the 
 pump, and caused work to be confined to the contact. In July 
 the water diminished, drifting was resumed, and in August, at 
 a distance of 118 feet southwest of the shaft, the Enterprise 
 vein was at last intercepted. The ore was 20 inches thick and 
 assayed 3.2 ounces of gold and 285.5 ounces of silver per ton. 
 In May, 1890, the Songbird and Enterprise mines, together 
 with much adjoining property, were acquired by the Enterprise 
 
 * A good example of the iniquitous operation of our absurd mining law. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 7 
 
 Mining Company, the operations of which were directed by the 
 writer from March 1, 1894, to February 28, 1895. 
 
 Fig. A shows the group of claims forming the property, and 
 the railway connecting them with the town of Rico. The mine 
 map (Fig. B) indicates the complex of drifts and crosscuts 
 which follows the ramification of veins. The workings aggre- 
 gate 8 miles in length. They have yielded ore whose gross 
 value exceeds $3,500,000. Of this nearly one-quarter has been 
 gold, the remainder silver.* 
 
 Entrance to the mine is made by the Group tunnel which 
 has a course S. 56 58' E., and consequently cuts the ore-bear- 
 ing veins almost at right angles. Moreover, since its line cor- 
 responds closely to the strike of the country, it intercepts the 
 veins at an approximately equal depth below the contact. It 
 would do so without variation, but for the step-faulting which 
 accompanies the vein-structure. 
 
 The tunnel or adit is 2920 feet long. Near the entrance the 
 contact is 210 feet overhead, at the breast it has approached to 
 within 35 feet. The largest drop is due to a down throw on 
 the so-called Leo cross-vein. 
 
 n. THE CouNTRY-EocK. 
 
 The Dolores, as it flows southward from the town of Rico, is 
 overlooked on the west by Mount Expectation, and on the east 
 by Newman hill. The river has eroded its own way and does 
 not follow the line of a fault. The Lower Carboniferous beds, 
 which form both its bed and the immediately flanking hillsides, 
 can be traced across the valley. On Newman hill they are for 
 the most part hidden by a deposit of Quaternary drift, the 
 maximum thickness of which is about 400 feet, diminishing 
 
 * The analysis of representative lots of ore gave 
 
 the following results : 
 
 First class. 
 
 Second class. 
 
 SiQz, 29. 2 per cent. 
 
 50 to 55 per cent. 
 
 Mn, 2.0 " 
 
 6 to 10 " 
 
 Fe, 11.8 " 
 
 6 to 10 " 
 
 Zn, 12.0 " 
 
 5 to 7 " 
 
 Pb, 10.2 " 
 
 2 to 3 " 
 
 S, 11.6 " 
 
 5 to 8 " 
 
 Au, 0.87 oz. per ton. 
 
 0.3 to 0.5 oz. per ton. 
 
 Ag, 221.50 " " 
 
 45 to 75 " " 
 
 The first class was mostly contact-ore, while the second class consisted of the 
 bulk of the product of the verticals. 
 
8 
 
 southwestward. The underlying shales, limestones and sand- 
 stones contain fossils which determine their stratigraphical place. 
 The intrusions of porphyrite,* both plentiful and irregular in 
 form, particularly at the northern end of Newman hill, afford 
 an explanation of the metamorphism of the sedimentary rocks. 
 
 The country enclosing the ore-deposits consists of these 
 shales, limestones and sandstones, having a strike !N". 20 "W. 
 and an average dip of 10. They are thinly bedded. Single 
 beds are not extensive, one layer dwindling in thickness until 
 it dovetails into another. Without necessary variation in 
 width, the composition may change so that lime graduates into 
 sandstone. These facts indicate that the sediments were laid 
 down in estuaries and in such shallow reaches of water as per- 
 mitted of swift changes in the conditions of sedimentation. 
 The fossil remnants are of a kind that accords with this view. 
 
 The foregoing description applies especially to that portion 
 (about 200 feet thick) of the formation to which the mine- 
 workings are practically confined. The veins do not penetrate 
 upwards beyond the horizon known as the " contact," and they 
 become barren at an average depth of about 150 feet below 
 that horizon. For this reason the overlying rock has been 
 merely penetrated in sinking to the ore-bearing horizon, and, 
 similarly, the underlying beds have only been pierced by one or 
 two unsuccessful shafts and bore-holes. 
 
 The beds above the contact consist, in ascending order, of: 
 
 2 to 5 ft. of lime breccia; 
 
 A thin bed of soft, crushed sandstone, which rarely reaches 
 a thickness of 9 ft., averages less than 1ft., and is occasion- 
 ally entirely absent; 
 
 * The following notes on a thin section of this rock, a hornblende-augite por- 
 phyrite, were given by Mr. R. C. Hills, geologist of the Colorado Fuel and Iron 
 Company. 
 
 Macroscopic Character. The rock is grayish in color, and shows white, opaque 
 feldspar (plagioclase), evidently much kaolinized ; also small, partly-altered 
 green hornblendes. Apatites are occasionally visible under the lens. 
 
 Microscopic Character. Under the microscope the feldspars are seen to be largely 
 altered to kaolin. So far as determinable in the only section available, they are 
 plagioclase. The green hornblendes are largely altered to chlorite. Small pale- 
 green augites and stout, relatively large apatites are rather numerous, together 
 with ore particles (magnetite). The granular groundmass is much kaolinized, 
 and abundantly distributed through it are grains and microlithic crystals of feld- 
 spar, also kaolinized. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 9 
 
 6 to 8 ft, of black shale ; 
 
 30 to 40 ft. of sandstone beds, and 
 
 40 to 50 ft, of black lime-shales. 
 
 The last graduate into a series of blocky limestones, the es- 
 carpments of which appear on the face of Mount Dolores. In 
 none of the beds of this series have profitable ore-deposits been 
 found, although large veins of calc-spar traverse them at inter- 
 vals. 
 
 The contact is not an ore-measure lying between two persist- 
 ent beds of shale and limestone, as has been stated.* The 
 composition of the encasing rocks is variable because of the 
 comparatively brief persistence of individual members of the 
 sedimentary series. It may be said, however, that the ore of 
 the contact is invariably found in rock which has undergone 
 shattering. An appearance of undisturbed solidity is occa- 
 sionally given by later cementation. Several raises put up to 
 the contact from the upper main level of the mine afford sec- 
 tions of the formation. Two are quoted. 
 
 No. 1. No. 2. 
 
 10 in. of compact pulverulent, 2 ft. of brown lime breccia, 
 
 lime, 6 in. of fine-grained sand- 
 14 in. of lime breccia, stone. 
 
 2 in. black shale, 21 in. dark blocky limestone, 
 
 19 in. limstone, 3 in. black soft shale, 
 
 12 in. sandy limestone, 28 in. blocky lime, 
 
 10 in. sandstone, 5 in. laminated sandstone, 
 
 1 in. parting of black mud, 18 in. black shale, 
 
 2 ft, lime shale, 1 in. parting black mud, 
 
 8 in. crushed lime, 15 in. light gray limestone, 
 
 25 in. blocky limestone, 1 in. parting, 
 
 10 in. soft sandstone, 58 ft. sandstone, 
 
 1 in. parting of shale, 2 J ft. shale, 
 
 Then a series of thin beds of 7 in. sandstone, 
 
 sandstone aggregating 21 3 in. shale, 
 
 ft. 4J ft. sandstone, 
 
 18 in. light-colored limestone, 2 in. lime shale, 
 
 10 ft, sandstone, 3 ft. coarse sandstone. 
 Then a further series of sandstones. 
 
 * J. B. Farish, Proceedings Colorado Scientific Society, vol. iv., p. 154. 
 
10 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 The section given in the first column came from the first 
 raise on the Jumbo No. 3 upper level, the second from a raise 
 on the Kitchen vein from the Enterprise level at the end of the 
 cross-cut between raises 7 and 8, Songbird. The linear distance 
 between the two sections is only 900 feet. Beyond the simi- 
 larity of the breccia, which marks the " contact," these two 
 sections are entirely dissimilar, and it seems impossible to re- 
 cognize any continuity in the stratification. The comparison 
 serves to explain the statement already made that the beds of 
 the series are notably non-persistent. The sketch reproduced 
 in Fig. 1 represents the face of a cross-cut where a bed of sand- 
 stone has been caught in the act, as it were, of merging into 
 
 a bed of lime-shale. 
 
 FIG. 1. 
 
 Non-persistence of Beds. 
 
 Further sections of the contact-horizon will be given when 
 we come to consider the ore-distribution at that level. 
 
 It has been seen that below the contact comes a series of very 
 thin lime and shale beds, interrupted by occasional sandstone 
 divisions. These beds are all dark in color, graduating from 
 coal-blackness at the contact to dark grays at a distance of 100 
 or 150 feet from it. As the contact is left, the sandstone beds 
 become more frequent, their grain is notably coarser, the lime- 
 stones become less shaly and more blocky, the black shale is 
 absent, and soon the workings penetrate into thick beds of a 
 coarse, light-colored quartzitic sandstone. 
 
 One or two shafts have been sunk, but the records which 
 have been kept are unfortunately so vague as to be useless for 
 the purposes of a geological section. The Jumbo shaft pene- 
 
THE ENTERPRISE MINE, RICO, COLORADO. 11 
 
 trated 524 feet below the contact, without any discovery of im- 
 portance. The Skeptical shaft, just north of the Enterprise 
 property, was sunk 365 feet in porphyrite and then penetrated 
 15 to 20 feet of shales and limestone. A hore-hole subse- 
 quently put down in the bottom of this shaft went through 200 
 feet of shales and limestone before entering quartzite, w r here 
 operations ceased. The Lexington tunnel, which is 400 feet 
 below the contact, penetrates the Newman hill formation for a 
 distance of 2740 feet, and is in coarse, light-colored, hard sand- 
 stone for most of its length. 
 
 There has always been much surmise regarding a certain 
 undiscovered " second contact." It has been the cause of much 
 nonsensical mining. The Enterprise Company, in 1893, sunk 
 the Jumbo shaft in search of this lower ore-measure, not realiz- 
 ing that, owing to the position of the shaft and the dip of the 
 formation, they would have to go down 300 feet below their 
 
 Fig. la 
 
 ibo Shaft 
 
 Scale, 150 feet =1 inch Group Tunnel 
 
 SECTION THROUGH JUMBO AND LAURA SHAFTS. 
 
 main adit before they would be even level, in a geological 
 sense, with existing northern workings. 
 
 This piece of exploratory work was badly planned and proved 
 without result. The neighboring company, the Rico-Aspen 
 Consolidated Mining Co. put down a bore-hole, which was as 
 barren of encouragement. The " second contact " of Newman 
 hill is a vain imagination. A hazy idea of the geology of Lead- 
 ville, blended with a misconception of that of Rico, has caused 
 the growth of an idea having no facts for its support. It was 
 suggested by the occurrence, on the hills north of the town 
 (above the village of Piedmont), of a series of at least three ore- 
 bearing contacts, and it seemed to be indicated by the devel- 
 opments in the Atlantic Cable mine. But deductions from this 
 evidence are vitiated by reason of the fact that the valley of the 
 Dolores, near the north of the town, is crossed by a large dike 
 of porphyrite, marking a fault which breaks the continuity of 
 the country on either side. 
 
12 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 The Atlantic Cable Co.'s bore-hole gave the following down- 
 ward section : 
 
 Feet. 
 
 Limestone, . . */.'- . . . . . 7 
 Lead- and zinc-ore, . . .' . ' '. ' . . ' , y . 4 
 Limestone, . -^'V- ? . . . '. : *'*i /''''' . 5J 
 Lead and zinc-ore, . . . ;. ? . . . 5 
 
 Limestone, . .13 
 
 White marble, . . . '**i . . . .20 
 
 Zinc-blende ore, ......... 3 
 
 Specular iron-ore 18 
 
 Limestone, .......... 43 
 
 Porphyrite, .......... 1 
 
 Limestone, 25 
 
 Porphyrite, .......... 2 
 
 Limestone, .......... 3 
 
 Mineralized porphyrite, ........ 3 
 
 Porphyrite, 21 
 
 The remaining 170 feet of the hole continued in quartzite. 
 To render the evidence complete, I now append the record of 
 the Rico- Aspen Co.'s bore-hole. This was sunk 20 feet north- 
 west of the Jumbo vein, between raises 7 and 8, at a point 85 
 feet below the contact. It was begun February 12, and fin- 
 ished September 10, 1895. From the collar to a depth of 481 
 feet the drill traversed alternating beds of limestone and sand- 
 stone ; the latter becoming coarser as depth was attained. 
 From 481 to 541 feet the drill traversed porphyrite. Between 
 541 and 573 feet the rock was quartzite. Then porphyrite con- 
 tinued to the bottom of the hole, at 706 feet. The evidence 
 afforded by these borings will be referred to after other mat- 
 ters have been passed in review. 
 
 III. THE ORE-OCCURRENCE. 
 
 In the investigation of the relation between the ore-occur- 
 rence and the rock-structure it is found that there are two dis- 
 tinct systems of vein-fissuring. One series of veins has a 
 N.E.-S.W. strike and a nearly vertical dip ; and this series is 
 crossed and faulted by a second system, having an approxi- 
 mately IN", and S. trend and a flat dip. The former are ore- 
 bearing and are called " verticals " or " pay-veins ; " the latter 
 are barren of valuable ore and are termed " cross-veins." Both 
 series fail to reach the present surface, save where deep erosion 
 has occurred ; because in coming up through the Carboniferous 
 
THE ENTERPRISE MINE, RICO, COLORADO. 13 
 
 
 
 formation they are abruptly terminated in their near approach to 
 a certain horizon marked by the occurrence of black shale and 
 beds of crushed lime. This, the contact, is disturbed by the 
 cross-veins. 
 
 The verticals are not productive immediately under the con- 
 tact. On the contrary, when within a distance varying from 5 
 to 15 feet from that contact they split up into stringers, which 
 scatter the ore so as to render exploitation unprofitable. Apart 
 from this dispersion of the vein, the total amount of ore which 
 it carries is also decidedly lessened. The plane of the contact 
 is itself ore-bearing ; the bodies occurring in the form of nar- 
 row channels ramifying through the crushed rock, in directions 
 which correspond exactly to the strike of the veins underneath. 
 It is a notable fact, moreover, that the cross-veins, barren as 
 they are, are yet related to ore-bodies on the contact as rich as, 
 if not richer than, those above the line of the verticals. 
 
 The knowledge of the relationships just outlined has proved 
 vital to the intelligent exploration of the mines ; and the theo- 
 retical consideration of them is, to the student of ore-deposition, 
 highly suggestive. The structure of the formation, on account 
 of the narrowness of the veins and the thinness of the beds 
 through which they pass, affords within the space of a few 
 square feet sections which ordinarily it requires acres to en- 
 compass. The coloring, moreover, of the minerals accompany- 
 ing the ore and of the rocks enclosing it, is so marked as to 
 assist the ready intepretation of structure, and enable the ob- 
 server to portray them by pen and pencil. For these reasons the 
 writer has endeavored to give the testimony collected by him 
 in the form of a series of drawings, rendering much comment 
 unnecessary. 
 
 IV. THE " VERTICALS " OR ORE-BEARING VEINS. 
 
 These belong to the simplest type of ore-deposit. They are 
 fractures cutting across the sedimentary rocks almost at right 
 angles to the bedding-planes. They have a simple structure. 
 Their width averages less than a foot; they are built along 
 fault-lines, are sensitive to the changes in the encasing rock, 
 and are themselves faulted by veins of later formation. 
 
 About a dozen veins have undergone noteworthy develop- 
 ment, and of these, five have yielded the bulk of the ore-pro- 
 
14 
 
 THE ENTERPRISE MINE, RICO, .COLORADO. 
 
 duction of the mine. The Enterprise, Jumbo No. 2, Jumbo 
 No. 3, and Hiawatha all dip to the northwest at angles varying 
 from 5 to 15 from the vertical; the Eureka is practically ver- 
 tical ; while the Kitchen, Swansea and Songbird veins have an 
 opposite (southeast) dip and a flatter angle, viz., from 12 to 
 22 from the vertical. Their strike varies between 50 and 
 
 FIG. 2. 
 
 l-r 
 
 pZSHET-j SHALE g^lVEIN 
 
 A Typical Pay -vein or Vertical. 
 
 65 east of north, the Eureka being conspicuous for its regu- 
 larity. 
 
 Fig. 2 is a typical illustration obtained from the end of one 
 of the levels. The vein is from 5 to 6 inches wide and cuts 
 the country-bedding at a right angle. It will be noted that the 
 ore occupies the line of a fault, the throw of which is 7 inches ; 
 the direction of the movement which caused it being indicated 
 
15 
 
 FIG. 3. 
 
 West 
 
 Scale, X in.- 1ft. 
 
 f .'':":'' " :':] F1NE SANDSTONE 
 
 S90 RHODOCHROSITE P 
 
 East 
 
 BICAN BAJUHmCO.N.Y. 
 
 L 1 QUARTZ g-^ 
 
 SONGBIRD VEIN 
 
 Scale, |-inch = 1 foot. 
 
 COARSE SANDSTONE 
 I BLENDE AND GALENA 
 
16 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 by the turning up of the bedding-planes on the hanging-wall of 
 the vein, and a corresponding bend in the partings on the foot- 
 wall side. The varied texture and color of the beds of sand- 
 stone and limestone rendered this structure very distinct. 
 Fig. 3 represents the Songbird vein, which has a dip op- 
 
 FIG. 4. 
 
 |-V.V : .:-I SANDSTONE 
 
 LIMESTONE 
 
 \\^\'\ VEIN QUARTZ ^f CLAY 
 
 Vertical and Horizontal Movements. 
 
 posite to that of the Jumbo No. 3, just described, The drawing 
 came from a stope about 30 feet below the contact, where the 
 vein happened to be entirely encased in beds of sandstone. A 
 fault is evident. Its throw is about 28 inches. The ore is 
 9 to 12 inches wide. On the hanging there is a casing, A A, 
 3 to 4 inches thick, which follows the vein throughout the 
 section. This casing, of dark sandstone, is separated by a 
 
THE ENTERPRISE MINE, RICO, COLORADO. 17 
 
 slight selvage from the outer country, but graduates gently 
 into the vein-stuff adjoining it on the east. On the foot-wall 
 there is a marked selvage, accompanied by crushed rock. 
 Two inclusions, C C, of sandstone occur within the ore. The 
 latter is banded by streaks of zinc-blende and by ribbons of 
 rhodochrosite within the quartz. D D is quartz. At B B the 
 ore has been slightly dislocated. 
 
 In Fig. 4 more complex conditions are represented. Two 
 dislocations of the country are evident. The vertical break 
 followed by the ore-formation has a throw of about 2 feet, 
 while the lateral fault, evidently of later occurrence, has caused 
 a disturbance measured by 9 inches only. It will be noticed 
 that the parting separating the upper fine-grained sandstone 
 from the bed of limestone has been brought into line with that 
 dividing the same bed of lime from the underlying coarser 
 sandstone. This coincidence must have facilitated the subse- 
 quent lateral shifting of the rocks. Such occurrences are fre- 
 quently observable in the mine. 
 
 It may be questioned whether the movement along the bed- 
 ding took place before or after the ore had been laid down. 
 There is evidence elsewhere in the mine that such movements 
 have both preceded and succeeded the vein-formation. In this 
 case it preceded, because the ore is seen to be not abruptly 
 broken off, but shaped to the structural conditions created at 
 this point previous to its precipitation. 
 
 A different state of things is disclosed in Fig. 5, which rep- 
 resents the Jumbo No. 2 vein, as seen in the end of the lower 
 level. Here, as usual, the ore occupies a fault-fracture, which 
 has dislocated the bedding to the amount of 20 inches ; but, in 
 addition, a later movement along coincident partings has broken 
 the vein and thrown it about a foot. The ore has been shat- 
 tered, and in the clay accompanying the line of fault there are 
 pieces of quartz and rhodochrosite, evidently due to this shat- 
 tering. The quartz-veins, unaccompanied by ore, observable 
 to the left of the vein, are of later origin. The dike of por- 
 phyrite will be referred to elsewhere. 
 
 In Fig. 6 a similar later movement, but this time in a ver- 
 tical direction, is illustrated. The Jumbo No. 3 vein, here 
 shown, follows a fault the throw of which is about 2 feet. 
 Since the ore was laid down a later shifting of the country has 
 
 2 
 
18 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 been accompanied by the formation of a fracture, which ap- 
 proximately follows the line of weakness of the older move- 
 ment, and breaks across the ore lying in its path. The amount 
 of this dislocation cannot be measured with certainty; it is 
 
 probably slight. 
 
 FIG. 5. 
 
 LIMESTONE 
 fVV^PORPHYRITE 
 
 '\VVJVEIN QUARTZ 
 
 Fault along Bedding-plane. 
 
 The veins are, as to their size, behavior and ore-bearing char- 
 acter, very sensitive to the structure of the enclosing rock. 
 They flatten when traversing lime, the increased deviation 
 from the vertical being accompanied by a diminution of ore. 
 Even in those cases where the actual width may not decrease 
 the percentage of valuable minerals does. In sandstone they 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 19 
 
 usually straighten up, and are marked by an enrichment. 
 When crossing a parting between the beds an offset of ore is 
 often formed underneath the parting. Some of these charac- 
 teristics are illustrated in Figs. 7 and 8, both representing the 
 Enterprise vein. In both the faulting along the ore-break can 
 be measured, since the dislocated portions of the same bed are 
 similarly lettered. 
 
 FIG. 6. 
 
 LIMESTONE 
 >/'-'! VEIN 
 
 Later Movement along Original Fracture. 
 
 Among the miners it was the common saying that " the vein 
 makes ore in sandstone," but my observations did not quite 
 confirm this generalization. When traversing lime the veins 
 tend to split up into stringers, and this is the case, to a lesser 
 degree perhaps, in sandstone. On the whole, my experience 
 was that unlike walls give the best environment for rich ore, 
 
20 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 and that a footavall of sandstone with a hanging of lime is a 
 particularly favorable combination. 
 
 In some cases comparatively modern shiftings of the country 
 are evidenced. Thus in Fig. 7 the flattened part of the vein, 
 E F, formed along the shale band, is crushed, and it is my be- 
 lief that this was caused by a movement along the bedding 
 
 FIG. 7. 
 
 
 PC"J LIMESTONE 
 
 I: :"::':| SANDSTONE 
 
 MUD 
 
 |^g%:| SHALE |j_\JVEIN 
 
 Vein Flattening along a Shale-bed. 
 
 long subsequent to the formation of the vein itself. The 
 stringers, G G, are also of late origin, and are composed of 
 barren quartz dissimilar to the gangue. In Fig. 8 there is a 
 similar jog in the vein, but in this case no crushing or disturb- 
 ance is suggested. 
 
 Pronounced selvages are not characteristic of these veins. 
 When noticeable they are usually in lime-beds. In sandstone 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 21 
 
 they are comparatively infrequent, and the absence of a parting 
 causes the ore to separate with difficulty from the sandstone, 
 into which it merges in such a manner as to cause the miners 
 to say that it is " frozen " to it. A casing of sandstone is occa- 
 sionally seen when the vein is entirely enclosed by lime, prov- 
 ing that the sandstone must have been shorn off upper beds in 
 
 FIG. 8. 
 
 '.SANDSTONE 
 
 VEIN 
 
 Influence of Encasing Rock upon Behavior of Vein. 
 
 the course of that movement which determined the existence 
 of the vein. This feature is illustrated in Figs. 9 and 10. 
 The first of these represents the Jumbo No. 3 vein, which in 
 this instance is identified with a fault of about 3 feet throw. 
 On the foot-wall the ore is divided from the country by a clay 
 selvage, but on the hanging there is no such parting. Toward 
 the bottom of the section the vein exhibits, on its hanging- wall, 
 
22 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 FIG. 9. 
 
 RHODOCHROSITE 
 
 g^g CRUSHED ROCK | 
 
 ( 3 QUARTZ 
 
 JUMBO NO. 3 VEIN 
 
 Scale, | -inch = 1 foot. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 23 
 
 FIG. 10. 
 
 
 J^ LIMESTONE 
 
 RHODOCHROSITE 
 
 CRUSHED ROCK 
 
 EUREKA VEIN 
 
 Scale, ^f-inch = 1 foot. 
 
24 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 a casing of country which changes from sandstone (A) to lime 
 shale (B) in accordance with the succession of similar adjacent 
 beds. The ore is distinctly ribboned by a symmetric alterna- 
 tion of vari-colored minerals. D is quartz. The vein is bi- 
 laterally symmetrical on either side of a central line marked 
 by vugs or cavities, C C, which are encrusted with quartz 
 crystals. The blende on each side of these vugs occurs in a 
 curiously spotty manner, suggesting brecciation. The smaller 
 vein, E E, consists of barren quartz and rhodochrosite. It is 
 of apparently later origin. 
 
 In Fig. 10 we have a very striking example of this ribboned 
 structure, to be discussed later on. For the present attention 
 is directed to the sandstone casings which follow the walls of 
 the vein. That on the hanging (F F) is scarcely an inch wide, 
 and has no appreciable selvage separating it from the outer 
 country. That on the foot-wall, A A, varies in thickness from 
 1 J to 2f inches, has a distinct parting dividing it from the coun- 
 try, and is, moreover, marked by a dark streakiness, suggesting 
 incipient ore-formation. In both cases these casings graduate 
 gently into the adjacent vein-stuff. 
 
 Each vein follows a fault-fracture. The shifting of the coun- 
 try is not likely to have been limited to a single line of fault- 
 ing, and it is found that just as the series of " verticals " indi- 
 cate contemporaneous and approximately parallel movements, 
 so there are also other minor shiftings sympathetic to these, 
 unaccompanied, it may be, by ore, and therefore unexplored by 
 the miner. Such subordinate faults are occasionally seen close 
 to the vein. Fig. 11 is a section of the Jumbo Fo. 3 in a stope 
 where it was non-productive, being represented merely by a 
 barren quartz vein, carrying a little rhodochrosite, but no valua- 
 ble sulphides. Two lines of faulting, A A and B B, are evi- 
 dent. The vein first follows one of these fault planes and 
 then deviates along cross-joints until it meets the other, 5 feet 
 further west, which it then accompanies. Both fault-lines are 
 marked by a selvage. The ore lies on the under side. The 
 main lode (DD) reappears (along BB) 5J feet lower down. 
 Deeper still it crosses over to the western fault, as its branch 
 had previously done, and, uniting with the latter, forms a strong, 
 rich vein, which continues undisturbed to a further depth of 30 
 feet, when another irregularity breaks its continuity. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 25 
 
 Fig. 12 affords farther evidence. In this case, as in the last, 
 the vein is seen where it is small and poor. Under such con- 
 ditions its structure is more readily discernible, because enrich- 
 ment and enlargement generally produce confused outlines and 
 are accompanied by a generous mineralization, destructive of 
 
 
 Vein Changing from one Fault-plane to Another. 
 
 definition. Hence the stopes most instructive to the scientific 
 investigator are least pleasing to the mine manager. In this 
 section there are two veins, both small, of which the western 
 may be regarded as a mere off-shoot. Two dislocations and 
 
26 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 several minor disturbances of the country are noticeable. The 
 western quartz-seam occupies a fault of a few inches, which dies 
 out into a mere distortion of the bedding ; the larger vein is 
 identified with a fault having a throw of 2 J feet. The bending 
 
 SANDSTONE 3dME r- SHALE 
 
 SANDY LIME Q^ QUARTZ 
 
 CRUSHED ROCK SELVAGE 
 
 Double Dislocations. 
 
 of the edges of the beds as they abut against the vertical quartz- 
 veins is very marked. Slight shiftings along bedding-planes are 
 indicated by the behavior of the small stringers traversing the 
 country. 
 
 The veins are built up of many-colored minerals, which give 
 them a rare beauty, and serve also to accentuate their structure. 
 
FIG. 13. 
 
 
 Scale of feet 
 
FIG. 14. 
 
 K 
 
 -ErTTTTi LIM!> A- .-....:> SAND- /. ...,.^_. > SANDY , ^^^ 
 
 >"->'] STONE l^Ll.^i; STONE [^-j,] LIMESTONE <^S> 
 
 a C ROCK HED C^ Q SEAM T 3 Z C^^VE.N 
 
 The Jumbo No. 3 Vein. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 29 
 
 Rhodochrosite and quartz enclose the sulphides of zinc, lead, 
 iron, copper and silver in the form of galena, blende, iron and 
 copper pyrites, argentite and stephanite. Native gold and 
 native silver both occasionally accompany the argentite. A 
 banded- or ribbon-structure is frequently brought about by the 
 alternation of quartz, rhodochrosite and the sulphides. This 
 structure assists the breaking of the ore, which will often part 
 in ribbons within itself more readily than it can be detached 
 from the encasing country. Fig. 25 illustrates a typical piece 
 of vein-stone.* The gentle graduation of ore into country is 
 noteworthy. The banding due to the rhodochrosite is a dis- 
 tinguishing feature, while the inclusion of portions of sand- 
 stone and the comb-structure of the quartz are additional testi- 
 mony as to the origin of the ore, which will be discussed under 
 another heading. 
 
 Much more might be said concerning the behavior of these 
 veins ; but sketches of the actual occurrences are better than 
 verbal description. Fig. 13 shows the Jumbo, No. 3 lode, as 
 seen in the stopes of the mine. The vein structure is illustrated 
 for a height of sixteen feet. It will be observed that the vein 
 follows a line of fracture which has faulted the country. 
 The vertical dislocation measures 2 J feet, and is rendered eas- 
 ily evident by the partings of shale which separate alternating 
 sandstone and limestone-beds. Following the section down- 
 ward, the ore is about 14 inches wide at the top, opposite A, 
 and is distinctly ribboned with bands of quartz, rhodochrosite 
 and zinc-blende, the last being also mixed with galena. The 
 vein continues fairly uniform for five feet, and is then inter- 
 rupted by a break opposite B, which indicates that the country 
 has been shifted to the right for a distance of six inches. This 
 movement took place at a point where a coincidence occurs be- 
 tween the partings between two sandstone-beds on one side and 
 lime-sandstone-beds on the other. Below this point the vein 
 opposite C is less regular, and divides into two branches, of 
 which the eastern carries all the pay ore, the western being 
 merely rhodochrosite and quartz. The latter, from its compo- 
 sition and structure, suggested to me, at the time, that it was of 
 later origin than the ore-bearing vein. Opposite D, four feet 
 
 * For a discussion of the evidence afforded by this drawing the reader is re- 
 ferred to the author's paper entitled "Vein- Wall," Trans., xxvi., 193. 
 
Fi. 15. 
 
 A 
 
 C ,KE ROCK LIMESTONE 
 
FIG. 16. 
 
 Downward Continuation of Fig. 15, Constituting Section of Jumbo 
 No. 3 Vein through Successive Stopes. 
 
32 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 below the last break, another occurs, a clean transverse fracture, 
 accompanied by scarcely any shifting. This, too, is found 
 where partings on opposite sides are so placed as to very nearly 
 make a continuous plane. The vein has been slowly diminish- 
 ing, and opposite E is only 8 inches wide. It continues to 
 dwindle. Independent little quartz stringers to the right sug- 
 gest disturbed ground. The vein decreases to a mere thread 
 and ends in a soft shale parting, Gr, two inches wide. But other 
 more interesting features demand notice. The ore no longer 
 clings to the left or western side of the faul1>fracture, which de- 
 termined the original vein-formation. Moreover, its course 
 downward is abruptly terminated. Several fragments of ore in 
 the shale band lead naturally to the continuation of the vein, 
 discovered to be 18 inches to the east. Here, opposite G, the 
 country has been shifted by a movement equal to about 1J 
 feet; but the behavior of the vein, especially the bending of 
 the ore near the points of fracture, suggests that the dislocation 
 of the country took place before the vein w T as formed. The 
 broken fragments indicate later movement also. Two feet 
 lower the vein is fractured and slightly dislocated. Below this 
 point the ore widens to 8 inches, and so passes out of view. 
 
 The conditions represented in Fig. 14 existed in the stopes 
 upon the same vein, about one hundred feet further north on the 
 strike. It is particularly interesting as illustrating the changes 
 not only in the vein but in the individual numbers of the series 
 of sandstone, shale and limestone-beds through which the vein 
 passes. Commencing at the top, K, of the section, the ore is 
 seen to be seven inches wide. About 1J feet lower, opposite 
 L, there is an incipient break in the vein, not sufficient to part 
 it. At five feet from the top, opposite M, a rupture has taken 
 place, accompanied by only a very slight displacement. Eleven 
 inches lower, opposite X, there is another break. M and IS" cor- 
 respond to B in Fig. 13. The ore here is 9 to 10 inches wide. 
 The vein is well defined and nearly vertical. Opposite O, three 
 feet below N", there is a more serious break. The vein is dis- 
 placed its own width, and for a height of six inches is broken 
 into several definite fragments. This severe shattering is due 
 to the fact that, in the absence of coincident partings, no clean 
 horizontal shifting of the country took place, but the movement 
 became more of a distortion. Compare the corresponding break 
 
THE ENTERPRISE MINE, RICO, COLORADO. 33 
 
 in Fig. 13, opposite D. The vein now decreases, as in Fig. 13, 
 and leaves, opposite P, the foot-wall of the main fault-fracture. 
 Opposite Q the ore is about 1J inches wide and two partings 
 exactly coincide, so that the horizontal shifting of the country 
 is expressed by a clean-cut fault in the vein amounting to a dis- 
 placement of 1J feet. A piece of ore occurs in the clay-seam, 
 midway between the divided parts of the vein. Below this the 
 ore increases. Opposite R there is an incipient fracture, cor- 
 responding to H in Fig. 13. The ore then widens steadily, and, 
 as it leaves the section at S, has a width of about one foot, 
 neatly ribboned. In this section the vertical throw along the 
 fault-fracture followed by the vein is a little less than in Fig. 
 13. 
 
 In Figs. 15 and 16 there is a representation of the same vein 
 as seen in a series of six stopes covering a vertical height of 33 
 feet. These stopes were at least two hundred feet north of the 
 place illustrated in Fig. 14, but in the same horizon of country- 
 rock. The lime and sandstone at the top of Fig. 15 can be 
 identified with the beds P, Q and W in Fig. 14, and with Z and 
 U in Fig. 13. 
 
 At the top of Fig. 15, opposite A, the vein is only 5 inches wide, 
 but is built up of rich sulphides, zinc-blende and galena. A 
 little lower, opposite B, the ore leaves the foot-wall of the fault- 
 fracture and then undergoes a dislocation of over two feet. This 
 movement along the bedding of the country occurs where part- 
 ings coincide. On the west the plane of movement, C, is not 
 accompanied by much selvage, but eastward there is a seam of 
 clay widening to 3 or 4 inches in thickness. Incidentally the 
 want of correspondence in the composition of the country on 
 the two sides of the vein attracts attention to the fact that it 
 follows a fault-fracture, the vertical throw of which is three feet. 
 Opposite D, one foot below the break, C, the ore exhibits what 
 miners call a " splice," that is, one distinct band of ore thins 
 out and another at the same time commences to appear. The 
 vein opposite E is about six inches wide, and rich. Just above 
 it was very poor and quartzose. Nothing noteworthy occurs 
 until, three feet lower (F), another splice is seen. The vein is 
 still small but fairly rich, and continues thus very uniformly for 
 another five feet, when (Gr) several features attract attention. 
 The vein appears fractured, although not separated, and abuts 
 
 3 
 
34 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 against a dike of porphyrite nearly one foot wide, which forms 
 the hanging-wall of the ore for a distance of five feet (G, Fig. 
 15, to H, Fig. 16). "When traced up and down the series of 
 stopes it was found to cease in both directions and to be there- 
 fore an intruding tongue. Its behavior is clearly shown in the 
 drawing, beginning opposite X, Fig. 15, and ending opposite Y, 
 Fig. 16. It varies little from a uniform width of slightly less than 
 afoot, except for a short distance (H to W), where it is squeezed 
 to a mere thread a few inches wide. The porphyrite is evi- 
 dently very sensitive to the structure of the country-rock 
 into which it has thrust itself. Opposite G the ore is about 7" 
 inches wide. It continues so for four feet downward, when (K) 
 another splice occurs and the vein widens. For the next six 
 feet the ore varies from 6 to 12 inches, and is then (L) slightly 
 dislocated. Below this the vein widens steadily and develops a 
 beautiful ribbon-structure, passing out of the section (M) with a 
 thickness of 14 inches. At the bottom of the section an in- 
 structive feature is presented. The ore-bearing vein leaves the 
 main fault-fracture (here shown by a line to the right), and 
 pitches slightly to the west. This is only temporary. Lower 
 down, outside the section here shown, it turns back and resumes 
 its course along the fracture which determined its existence. It 
 will be noted that the ore in leaving the main fault-line (about 
 opposite Y), follows a line of minor fracturing which shows a 
 slight but evident dislocation also. 
 
 These four sections, Figs. 13 to 16, show how the behavior 
 of the vein is determined by the structure of the enclosing 
 rock. The fracturing through the country, which opened a 
 possible channel for the circulation of the mineral-bearing 
 waters, was continuous but irregular. The irregularity was 
 due, in the first place, to the varying composition of the beds 
 through which the fracture passed. That fracturing was ac- 
 companied, as we have seen, by a vertical displacement of from 
 two to three feet. The direction of the throw is beautifully 
 evidenced by the bent edges of the partings in the country on 
 either side ; on the hanging, upward ; on the foot-wall, down- 
 ward. 
 
 The horizontal shiftings which now break the vein occurred 
 in part before ore-deposition, but mostly afterward. The later 
 movements were also the parents of the quartz-stringers which 
 
THE ENTERPRISE MINE, RICO, COLORADO. 35 
 
 now fringe the vein, as at C and F in Fig. 13, and M. and P. 
 in Fig. 14. They represent the healing-action of later solu- 
 tions, circulating along a reopening of the old passage-ways. 
 
 The three sections, Figs. 13, 14 and 15, illustrating the same 
 horizon in the country, at considerable distances apart, serve to 
 prove how individual members of the sedimentary series change 
 in composition. The two beds, E and Z, both limestone, in 
 Fig. 13, become, in going northward, the two beds, P and Q, 
 one limestone and one sandy lime. In Fig. 14 the relative 
 thicknesses have changed. Again, in Fig. 15, the same beds, 
 now seen 200 feet further north, are to be identified in the 
 single bed of limestone extending from A to C. The under- 
 lying sandstone also shows variations at the different points. 
 It is noteworthy, at the same time, that the vein acts much in 
 the same way when traversing identical beds at different points. 
 
 The subsidiary fracturing, seen in Fig. 15, to the east of the 
 vein, between C and G, is instructive. That this structure 
 usually accompanies vein-faulting I certainly believe. The 
 breast of a slope or the face of a drift rarely exhibits it, because 
 mining does not require that the ground should be broken for 
 a width necessary to make it visible. This structure, the sheet- 
 ing of the country, is very marked at Cripple Creek, in Colo- 
 rado, and is the origin of parallel and multiple veins. 
 
 Y. THE CROSS- VEINS. 
 
 These veins, although non-productive, play an important part 
 in mining operations, because they dislocate the ore-bearing 
 " verticals," and are themselves related to extensive ore-bodies 
 on the contact. The picture they present is that of white bands 
 of crushed quartz, cutting through everything, as distinguished 
 from the verticals, which are like pink ribbons of rhodochrosite, 
 traversing the sedimentaries with difficulty because of their 
 faulting by these cross-veins. 
 
 The latter are built upon fault-lines marking movements 
 greater in extent than those accompanying the older, ore-bearing 
 fractures. They are essentially quartz-veins. A variable 
 amount of crushed country accompanies the quartz. Rhodo- 
 chrosite and valuable* sulphides are notably absent. When 
 
 * Many assays were made of the pyrites from cross-veins encountered in cross- 
 cuts. Traces of gold and 4 to 8 ounces of silver were about the best results. Oc- 
 
36 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 seen, they represent broken fragments of pay-veins traversed 
 by the path of the cross-vein. Next to quartz, iron pyrites is 
 their most characteristic mineral. The pyrite is in a crumbly, 
 easily disintegrated state, very unlike the solid crystalline con- 
 dition in which it appears amid the ore of the verticals. Some- 
 times no foreign minerals are present in notable quantity, and 
 the cross-vein is simply a seam of crushed country, softening 
 into mud. This the Cornishman would call " fluccan." 
 
 Fig. 17 represents a cross-vein in the breast of a drift on the 
 Jumbo "No. 3 vein, which had met the cross-vein and had been 
 faulted by it. The Jumbo vein was intercepted by this drift 8 
 feet further ahead. Three breaks are noticeable, each marked 
 by faulting. The cross-vein itself lies between two unlike beds 
 of lime, marking a fault which evidence elsewhere along the 
 drift showed to be 6 feet. The lime on the foot-wall is sepa- 
 rated from a series of thin beds, exhibiting a good deal of 
 variety, by a curving line of selvage, following a fault whose 
 throw is 4 feet. Then come beds of shale, crystalline lime and 
 sandstone, traversed by a dislocation of 10 inches. In each case 
 the down-throw is on the hanging-wall. The cross-vein is almost 
 vertical and carries fragmentary rhodochrosite torn from the 
 Jumbo vein. 
 
 Fig. 18 illustrates another cross-vein in the act of cutting 
 through the Jumbo vein. The line of the former is deflected 
 in breaking through the latter. To the left the series of beds 
 consists of blocky lime, lime shale, broken lime, limestone, 
 black shale, closely laminated lime and light gray sandstone. 
 On the right this series is seen to be succeeded by beds of dark 
 sandstone. The fault along the cross-vein is 4 J feet, obliterating 
 the displacement which must have accompanied the line of the 
 ore-bearing vein. The latter is thrown its own width, 10 inches. 
 It has been shattered by the cross-vein, but appears to have 
 been repaired and reconsolidated (since its displacement) by 
 
 casionally good assays were obtained, but the pieces from which these samples 
 came were invariably marked by the presence of fragments torn from the pay- 
 veins. Nevertheless, from a scientific standpoint, pyrite containing a few ounces 
 of silver is as much ore as blende or galena, carrying much higher values. In this 
 connection it may be added that the pyrite of the verticals is not notably silver- 
 or gold-bearing unless admixed with copper pyrites, blende or galena. The 
 pyrite and quartz, whether in the cross-veins or the verticals, is not a sign of 
 valuable ore. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 37 
 
 healing seams of quartz, which now ramify through the pre- 
 viously hroken rhodochrosite. This cross-vein was distant 28 
 feet from the one described above. 
 
 The comparatively small scale of the rock-formation affords 
 many excellent illustrations of phenomena usually requiring 
 
 FIG. 17. 
 
 BANKNOTE CO. N.V. 
 
 j^ 17 ] LIMESTONE \^\ QUARTZ \. 
 
 ( X tfI ^LVAGE 2] RHODOCHROSITE 
 
 C::;T-j SANDSTONE g^T] SHALE 
 
 [f|U CRUSHED COUNTRY 
 
 A Cross-vein in Limestone. 
 
 large areas for their exemplification. Some of the dislocations 
 are so slight that they can be seen to die out in mere distortions. 
 See Figs. 19 and 20. The former is particularly instructive. 
 It shows the sides of a cross-cut which joins the workings on 
 the Hiawatha and Enterprise veins. Near the floor of the cross- 
 cut there is a fault of about 5 inches which follows a seam of 
 
38 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 clay nearly 1 inch thick. This dislocation diminishes upward ; 
 the thin beds break less and bend more, until finally the verti- 
 
 FIG. 18. 
 
 The Jumbo, No. 3, Vein Faulted by a Cross-vein. 
 
 cal displacement fades out in horizontal shifting. The latter is 
 clearly evidenced by the minute multiple step-faulting of a 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 FIG. 19. 
 
 39 
 
 SANDSTONE: 
 
 ~ j BLACK SHALE 
 
 ~* 
 
 rX-^j LI.ME SHALE 
 
 Disappearance of a Fault. 
 
 LIMESTONE 
 
40 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 quartz-seam in the shale, near the roof of the cross-cut, which 
 
 FIG. 20. 
 
 tf3 LIMES r NE S3 SANDSTONE ggg) SHALY-SANDSTONE CLAY 
 
 Disappearance of a Fault. 
 
 indicates that the flexibility o the shale enabled it to resist 
 
THE ENTERPRISE MINE, RICO, COLORADO. 41 
 
 fracturing by dissipating the force of the vertical movement in 
 a sliding of the laminae over one another. Fig. 20 conveys the 
 same lesson. The three quartz-seams here shown follow lines 
 of lessening vertical movement; the distinct faulting of the 
 beds in the lower part of the section dwindling until in the 
 upper portion only a slight distortion of the country is to be 
 discerned. These examples illustrate how large faults may 
 gradually disappear, and suggests why the vein-systems of 
 Newman hill terminate in their approach to the horizon known 
 as the " contact." 
 
 Fio. 21. 
 
 j LIMESTONE {.ZHTJ SHALE [ (QUARTZ 
 
 rv SANDSTONE ^ 
 
 Faulting of Cross-vein along Bedding-plane. 
 
 The cross-veins are themselves displaced in some instances 
 by slight later movements which have taken place along the 
 bedding-planes of the country, such as indicated in Fig. 21, 
 where a small south-dipping cross-vein is thrown 5 inches along 
 the parting between beds of limestone and sandstone. 
 
 The dislocation of the ore-bearing veins by the cross-veins 
 necessitates the employment of scientific methods in mining. 
 The mine-workings of Newman hill are needlessly tortuous and 
 complex, because most of them have been directed by men blind 
 to the indications of geological structure. The expensive results 
 of a bewilderment due to this cause are well illustrated in the 
 case of the Hiawatha vein, between raises No. 9 and No. 11 on 
 the main level. This particular instance is quoted because it 
 appears in Mr. J. B. Farish's paper on Newman hill.* His 
 
 * Proceedings of the Colorado Scientific Society, vol. iv., p. 159. 
 
42 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 drawing is here represented (in Fig. 22), together with another 
 (Fig. 23) based on a very close sifting of the evidence, accom- 
 panied by a careful survey. 
 
 Referring to Fig 22, I quote Mr. Farish's description : 
 
 "It illustrates the occurrence of a fault in the Enterprise vein and the deflec- 
 tion of the Hiawatha vein by the same cross-fissure. The break in the Enter- 
 prise vein is seen to be sharp, while the Hiawatha vein is not faulted, but makes 
 along the cross-vein for nearly 100 feet before emerging from its walls and resum- 
 ing the original course." 
 
 The vein called the Enterprise in the above description is 
 not the Enterprise, but the Songbird. The former vein has 
 
 FIG. 22. 
 
 Mr. Farish's Drawing of the Hiawatha Vein. 
 
 never been found in this particular part of the mine, because it 
 breaks up into unimportant stringers and is not definitely re- 
 cognized until nearly 400 feet further north. The Enterprise 
 dips east slightly, the Songbird dips west flatly. In their strike 
 northward the two veins unite. 
 
 The cross-vein faults both. If Fig. 22 were correct the for- 
 mation of the Hiawatha would be later than that of the cross- 
 vein, and the latter must be later than that of the so-called 
 Enterprise vein, and the ore-bearing veins would not be of con- 
 temporaneous origin. Such, however, are not the facts. 
 
 The cross-vein strikes the Songbird almost at right angles 
 and throws it to the right. When it meets the Hiawatha, it 
 throws that vein to the left. The Hiawatha and Songbird dip 
 in opposite directions. Both faultings are in accord with 
 Carnall and Schmidt's rule.* 
 
 * In Fault-Rules, by Francis T. Freeland, Trans. , xxi., 499. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 43 
 
 The representation (in Fig. 22) of the Hiawatha as following 
 the cross-vein is, in my judgment, incorrect; the error having 
 been made by mistaking the " drag " for ore in place. The 
 same error is repeated in another drawing (Fig. 24) by Mr. 
 
 FIG. 23. 
 
 U9H 
 
 The Faulting of the Hiawatha and Songbird Veins by a Cross-vein. 
 
 Farish,* which Professor Kemp has perpetuated in his treatise 
 on ore-deposits. f The value of the latter as a book of refer- 
 ence makes it imperative that the mistake should be pointed out. 
 
 * Pages 158 and 159 of the paper cited. 
 
 f The Ore-Deposits of the United States, by James F. Kemp, p. 20. 
 
44 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 Mr. Farish says that the occurrence represented by him in 
 Fig. 24 is an instance of the " bend of a vertical pay-vein as it 
 approaches an intersecting cross-vein," and also, that "the 
 Jumbo vein, as it approaches and departs from the cross-fissure 
 is considerably disintegrated, the numerous seams and stringers 
 striking diagonally through the cross-veins." Professor Kemp 
 uses this drawing to exemplify the faulting of one vein by an- 
 other. Mr. Farish's description would make it appear that the 
 cross-vein existed prior to the Jumbo vein, and that the latter 
 was bent by the former, which it traversed in seams and 
 stringers. Yet the drawing, even as it is, represents no fault, 
 but merely the bending of one vein by another, of possibly 
 contemporaneous origin. 
 
 The real conditions are represented in Fig. 26, which shows 
 
 FIG. 24. 
 
 Mr. Farish's Drawing of the Jumbo and a Cross-vein. 
 
 how the cross- vein faulting the Jumbo carries shattered frag- 
 ments of the latter between its two dislocated parts. The con- 
 fusion caused by Mr. Farish's attempt to distinguish between 
 cross-veins that fault pay-veins, of necessarily older origin, and 
 cross-veins followed by pay-veins, of consequently later forma- 
 tion, is due, I think, to a failure to recognize a very simple 
 feature of vein-faulting. I refer to those fragments of the ore 
 of the older vein which have been broken off' by the fault- 
 fissure and are found scattered amid the newer filling of the 
 latter along that part of its course which lies between the two 
 disrupted portions of the older vein. This is the " drag," 
 which is so valuable an aid in mining, because it enables the 
 miner to trace the direction of the throw. 
 
 The faulting of the " verticals " by cross-veins is a prominent 
 feature in the Enterprise mine. When half a dozen drifts were 
 running on the several pay-veins a fault was encountered about 
 once per month. In other words, the distance between the 
 cross-veins averaged from 65 to 100 feet. Failure to apply the 
 
D 
 
 I 50 i 
 
 m C S 
 
THE ENTERPRISE MINE, RICO, COLORADO. 45 
 
 elementary rules of faulting and to make such observations, 
 measurements and calculations as would serve to identify a 
 cross-vein as it passed through the series of nearly parallel ver- 
 ticals, has caused much unnecessary expenditure on Newman 
 hill. More broken ends of faulted-veins were happened upon 
 by accident in " drifting " than were discovered by intelligent 
 search. The practical importance in mining of the study and 
 interpretation of geological structure is forcibly emphasized by 
 this record of experience. 
 
 Out of over two hundred instances of faulting noted during 
 my twelve months' direction of the Enterprise mine, I detected 
 only one (and that an uncertain) exception to Carnall and 
 Schmidt's rule, which is stated by Mr. Freeland as follows :* 
 
 ' ' If the fault be encountered on its hanging-wall side, after breaking through it, 
 prospect toward the hanging-wall side of the vein ; on the contrary, if from the 
 foot- wall side, then prospect toward the foot- wall side of the vein." 
 
 " This rule, as Mr. Freeland says, " applies only to normal 
 faults, and is, in addition, subject to an important exception."f 
 I do not cite it as the statement of a universal law. In other 
 districts other rules may be found applicable. NOT is it neces- 
 sarily to be expected that in any one district a single rule only 
 will obtain. But if in a given locality the prevalence of a 
 given fault-rule (expressing the habit of the veins in that local- 
 ity) can be demonstrated, a working-hypothesis of immense 
 value is thereby furnished to the miner. My remarks in this 
 connection are to be taken, therefore, as applicable only to the 
 district here under consideration, or to other districts in which 
 similar conditions may be determined by experience. 
 
 When a cross-vein intersects a pay-vein at an acute angle it 
 is practicable to follow the trail of the latter, as evidenced by 
 the scattered fragments constituting the " drag." When, how- 
 ever the faulting occurs at a large angle there is less evidence 
 of the direction of the throw, and a level driven on the cross- 
 
 * Trans., xxi., 499. 
 
 f " Normal faults " are those in which the rock forming the hanging-wall of the 
 fault has moved downward along the foot-wall of the fault. The exception to 
 Carnall and Schmidt's rule mentioned by Mr. Freeland in the above quotation is 
 that of an obtuse fault-angle. The rule might be so stated that this would be no 
 exception, as the case is simply one of an acute-angled fault, approached from the 
 other side. 
 
46 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 vein until it meets the other portion of the disrupted vertical 
 would involve turns too sharp for subsequent use in tramming. 
 It might thus be necessary, after finding the continuation of the 
 pay- vein, to run a new piece of level for practical mining pur- 
 poses. But if the direction of the throw be known from pre- 
 
 FIG. 26. 
 
 Faulting of the Jumbo by a Cross-vein. 
 
 vious experience, the heading can be so turned as to strike the 
 vein beyond its dislocation by a course of minimum deflection, 
 making a practicable mine-level. 
 
 When a cross-vein meets a vertical at a very small angle a 
 
 Fio. 27. 
 
 Outline of Mine Levels 
 
 Ore Vein 
 
 Cross Vein 
 
 AMERICAN BANK NOTE CO.N.Y. Y 
 
 A Vein Faulted almost at Eight Angles. 
 
 A Vein Faulted at a Small Angle. 
 
 slight throw, as measured at right angles to the strike, becomes 
 sufficient to produce a wide separation between the broken 
 ends as measured along the course of the pay-vein. In such 
 cases it is easy for the unobservant miner to be misled by the 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 47 
 
 unapparent deviation in his level and to mistake a cross-vein 
 carrying fragments of lode-matter for the pay-vein itself. (See 
 the diagrammatic sketches in Figs. 27 and 28.) 
 
 29. 
 
 |:-iiji:-:3 SAN DSTONE F^^tZ^y 
 
 LIMESTONE 
 
 DISORDERED LIME 
 
 SOFT CR USHED L 'ME 
 
 Cross-vein as seen in the Breast of a Drift on Jumbo No. 2. 
 
 The rhodochrosite is a great aid in tracing the ore-bearing 
 veins because its bright color renders it readily distinguishable 
 amid the white quartz or the dark shattered country of the 
 cross-veins, and its absence distinguishes the latter just as its 
 presence characterizes the pay-veins. 
 
48 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 Figs. 29, 30 and 31 illustrate the behavior of two cross-veins, 
 encountered in following the Jumbo "No. 2 lode. Fig. 29 shows 
 the cross-vein in the breast of the level. It consists of 2 to 3 
 
 SANDSTONE A 
 
 LIMESTONE 
 
 1 BLACK 
 =. CRUSH ED 
 
 L|ME 
 
 SANDSTONE B 
 
 SELVAGE 
 RHODOCHROSITE 
 
 Two Cross-veins Approaching Each Other. 
 
 feet of crushed country, enclosing stringers of quartz. There 
 is a fault, but its extent cannot be determined. The wedge of 
 sandstone observable near the floor of the drift marks the be- 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 49 
 
 '.Iv:"". : :': SANDSTONE 
 
 BLACK CLAY 
 
 jr^X- LIMESTONE 
 
 VEIN 
 
 (Igp^a BLACK LIME 
 SHALE 
 
 f V. 'V.if - '.\C R U S H E D 
 I3S?- :< ^S3 QUARTZ 
 
 ^SSSSA SELVAGE 
 
 A Vertical and a Cross-vein Intersecting. 
 
 f-rx CRUSHED SANDSTONE 
 
 ' 
 
50 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 E FIG. 32. 
 
 
 ._ *^.*--i. * -^.<-.:-.-- 
 
 
 t.M E -SHALE BLACK SHALL 
 
 Ojfyl CRUSHED ROCK 
 1 
 
 LAMINATED 
 LIMESTONE 
 
 Scale of Feet 
 
 Porphyrite Dike at the Contact. 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 51 
 
 ginnings of a separation which Fig. 30 shows to be the depar- 
 ture of one of two consolidated cross-veins. One of these 
 
 FIG. 33. 
 
 BLACK SHALE 
 
 HARD SANDSTONE 
 
 r* CROSS VEIN 
 
 BREAST OF CROSSCUT WEST OF ENTERPRISE LEVEL, APRIL 10TH. 1894 
 
 began at this time to exhibit pieces of rhodochrosite, which 
 soon afterwards led to the finding of the vein. Fig. 31 illus- 
 trates another cross-vein. The structure is complicated. The 
 narrow seam, A A, and its enclosing vein-filling have been 
 
52 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 FJG. 34. 
 
 East . 
 Scale, '% in.=l ft. 
 
 I SANDSTONE | ~^_T r ' \ LIMESTONE 
 
 RHODOCHROSITE f ") QUARTZ ffiSwl BLENDE 
 
 AMERICAN BANK NOTE ( 
 
 "Z^JLIME SHALE 
 
 | CRUSHED ROCK 
 
 KITCHEN VEIN 
 

 THE ENTERPRISE MINE, RICO, COLORADO. 53 
 
 faulted along a bedding plane, B B, and subsequently a move- 
 ment along the hanging-wall of the cross-vein has led to another 
 dislocation, a down-throw of the country and a distortion of 
 the former line of movement. It is interesting to note that the 
 secondary companion cross-vein thus formed consists of crushed 
 sandstone, D, in the upper part of the section, and of black 
 lime, E, which has been crushed into clay, in the lower part. 
 This change corresponds with the alternation of rock in the 
 enclosing country. 
 
 Fig. 33 illustrates a fine example of double faulting. The 
 steep cross-vein has caused a displacement of a little over 2 
 feet, which is very clearly marked by the dark band of sand- 
 stone. Subsequently a shifting along bedding-plane has faulted 
 the cross-vein about 20 inches. 
 
 Fig. 34 is a section of the Kitchen-vein, as seen in the face of 
 a south drift. This vein dips westward. The example is of 
 value because of the inclusion of fragments of country-rock. 
 Of these, some (CC) are sandstone and others (DD) lime. 
 Their distribution corresponds with that of the rocks on the 
 foot-wall, and suggests that they were torn off the enclosing 
 country. The mineralization of the rock and the substitution 
 of ore is suggested by the fact that each of these included pieces 
 has a well-marked rim of rhodochrosite. On the hanging-wall 
 there is no parting from the country ; on the foot>wall the ore 
 is readily detached, because of the existence of a continuous 
 selvage of black mud. Ribboning, due to alternations of quartz, 
 rhodochrosite and blende, is well marked in the upper hanging- 
 wall portion of the section. This vein follows a fault-fracture, 
 the throw of which exceeds 5 feet, an amount unusual to the 
 pay-veins of the Enterprise mine. 
 
 The occurrence of dikes and tongues of porphyrite has been 
 noted incidentally. The deep shafts and bore-holes have en- 
 countered large thicknesses of it among the sedimentary rocks 
 underlying the horizon of the existing mine-workings. The 
 sedimentaries have been found hardened and otherwise aft'ected 
 in the vicinity of the eruptive rock, so that sandstone appears 
 as quartzite and limestone is converted into marble. What the 
 real character of this body of porphyrite may be cannot be de- 
 termined from the evidence at my disposal. The more general 
 observations of the gentlemen of the Geological Survey will 
 
54 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 doubtless throw much light on the matter. To the mining en- 
 gineer one fact stands out very prominently, that whether in 
 their strike northward, approaching the porphyrite of Silver 
 
 Fig. 35. 
 
 Quartz 
 
 Limestone 
 
 Crushed Rock 
 
 A TYPICAL CROSSVEIN. 
 
 creek, or in their extension downward, toward the lower-lying 
 body of that rock, the veins become impoverished of pay-ore. 
 In view of the general recognition of the beneficent association 
 of veins with eruptive rocks, this is very instructive. The ex- 
 planation suggests itself that though the shattering of the 
 country accompanying the intrusion of the porphyrite aided 
 
THE ENTERPRISE MINE, RICO, COLORADO. 55 
 
 vein-formation, because of the passageways thereby developed 
 for the circulation of underground waters, yet at the same 
 time the immediate neighborhood of hot masses of eruptive 
 material did not favor the precipitation of ore, and that the 
 best deposition took place at such a distance as permitted the 
 cooling of the waters and the consequent laying down of the 
 metals they carried in solution. 
 
 The veins penetrate the porphyry. The contact in many 
 places carries fragments of porphyry. These facts prove, as 
 would be readily surmised, that vein-formation succeeded the 
 intrusion of the porphyry. 
 
 In the stopes irregular tongues of porphyrite were occasion- 
 ally observable. As they only followed the vein for a short 
 distance in its strike and dip, it was not possible to find out 
 much about them. Such occurrences are seen in Figs. 5, 15 
 and 16. Fig. 32 is a drawing, which I made with particular 
 care, showing how a dike is shattered at the contact. The 
 porphyrite is 14 inches wide. Along the parting AB it is 
 fractured, and a clay selvage across it suggests later movement 
 (in the direction of the strike, so that the cross-section does 
 not show it). At the level of CD the dike is smashed to pieces. 
 A disturbance along the contact has shifted some, of the frag- 
 ments. The regular passage of the dike upward has been in- 
 terfered with at the contact, and, previous to the shattering, it 
 seems to have divided into branches, of which three (termina- 
 ting in the sketch at E, F and G) still survive. The contact itself, 
 here marked by a thickness of nearly 5 feet of crushed shale, 
 crushed sandstone and lime, contains numerous fragments of 
 porphyrite. Apart from its bearing on the origin of the dikes, 
 this drawing illustrates how the contact barred the progress 
 upward of fissuring of every kind. 
 
 VI. THE CONTACT. 
 
 As the ore-bearing veins are followed by the mine-workings* 
 they are found to split up, weaken and become impoverished 
 
 * Entrance to the mines is made through long adits which aim to cut the veins 
 at a depth of 50 to 100 feet below the contact. Hence the regular vein -structure 
 is first seen, and the other complications come under notice as the stopes and raises 
 are ascended. This order has been observed in describing them here. 
 
56 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 at a certain horizon, lying from 5 to 20 feet below a zone of 
 crushed rock, in which are enclosed ore-bodies richer than those 
 of the veins themselves. It is rarely that even diminished seams 
 of ore survive so as to connect with the ore on this contact. 
 Ordinarily the highest stope on the " vertical " is separated from 
 the nearest stope on the " contact " by a few feet of black shale 
 
 Fig. 36. 
 
 Black finely laminated Shale 
 
 Ore 
 
 Limestone 
 
 JUMBO No. 2. VEIN AT THE CONTACT 
 
 and lime, containing, at best, only scattered remnants of the 
 vein. Figs. 36 and 37 give simple examples. Occasional sec- 
 tions show no connection between the vertical and the contact 
 overhead. Such small quartz or rhodochrosite threads as do 
 occur have no continuity. 
 
 The cross-veins behave in relation to this contact in a man- 
 ner very similar to the pay-veins. Since they are barren of ore, 
 there are no workings which folloAv the cross-veins in their 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 57 
 
 immediate approach to the contact, but there is scattered evi- 
 dence* sufficient to confirm this statement. There is, how- 
 ever, a notable difference between the behavior of the two 
 systems of vein fissuring when they reach the contact. The 
 economically important observation has been made that the 
 cross-veins are less regularly topped by ore-bodies along the 
 
 Fig. 37. 
 
 _ I ' __ ~ - Black Shale 
 
 Sandstone 
 
 <?'>'* 
 
 " '. : * v vf " * ~ * ' & ' '* 
 
 il?&;&*$&$ 
 
 ,^^^^/^m^wM. 
 
 71+i'l'^^^t^, 
 
 - ,-r H^'- ^' 
 
 - -vl -' 
 
 ^I-X^ 
 
 Brecclated Lime 
 
 Ore 
 
 Gray Limestone 
 
 Black Lime 
 
 A TYPICAL CONTACT 
 
 contact ; but, on the other hand, such ore-bodies as have been 
 found over cross-veins have been usually larger and certainly 
 richer than those apparently related to underlying verticals. 
 
 The dislocating influence of the pay-veins appears to die out 
 in its approach to the contaekzone, so that the latter undergoes 
 a mere undulation or roll along its bedding-planes. At the 
 same time the pay-veins become unrecognizable, even as minute 
 
 * Obtained from stopes under the contact, in places where a cross-vein happens 
 to cut a vertical as it is dying out. 
 
58 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 seams or partings, in the rocks above the contact. In the case 
 of the cross-veins, however, a more serious disturbance of the 
 contact-zone is indicated by violent bends and occasional step- 
 faults. The cross-vein itself, though it does not reappear above 
 the contact as a strong quartz-seam, is yet represented by a 
 well-developed division in the country accompanied by selvage. 
 Fig. 38 represents a section along the contact, where it is dis- 
 located by a cross- vein. The latter, A B, splits at the contact, 
 both branches, B C and B D, following fault-lines. The ore of 
 the contact, which is here related to the Jumbo No. 2 vein, 
 consists of low-grade quartz from a couple of inches to more 
 than a foot in thickness, overlain by a thin bed of black shale 
 and underlain by limestone. Above the shale is a bed of brec- 
 cia, about 2 feet thick, composed of fragments of limestone, 
 with occasional pieces of porphyrite and shale. It will be 
 noticed how the quartz-ore follows the bedding and the con- 
 necting fault-fissures. 
 
 When the contact was first penetrated by the shafts sunk 
 from the surface (through the drift covering the sandstones and 
 limestones which contain the ore-deposits) it was supposed to be 
 a " flat vein." When later developments proved it to conform to 
 the bedding of the country, it became recognized as distinct 
 from the other vein-systems which cut the bedding at a right 
 angle. Hence grew the idea that there existed here a lime- 
 stone-shale contact similar to that of Aspen and resembling 
 the ore-bearing zones in the Carboniferous blue lime of Lead- 
 ville. More extensive exploration dissipated the hope of a con- 
 tinuous ore-bed, but although the occurrence of harrow chan- 
 nels of rich mineral, ramifying through the brecciated beds of 
 the contact, was demonstrated, it was not at first seen how 
 clearly these corresponded with the strike of the two vein- 
 systems, the upward course of which was terminated by the 
 contact. The recognition of this relationship was a key un- 
 ravelling many perplexities, and a light to the intelligent ex- 
 ploration of a territory of complex geological structure. 
 
 The contact is not, as the term might imply, a continuous 
 plane of division between two rock formations, nor does it mark 
 the parting between the two adjoining beds of ore formation. 
 The accounts which have been given of a " coiitac1>limestoiie," 
 overlain by a " drab shale " and underlain by a " finely lamina- 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 59 
 
 
 ;^y? : ^?y* 
 
 Slti 
 
60 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 ted shale,"* may describe certain sections of this ore-bearing 
 horizon, but they do not characterize it as a whole, and they 
 
 Fig. 3J. 
 
 THE CONTACT ABOVE THE ENTERPRISE VEIN 
 
 Lime Breccia 
 
 Lime Breccia 
 
 Blocky Lime 
 
 Limestone 
 
 give a misleading idea of its real nature. In the three sections 
 already given, in Figs. 36, 37 and 38, the contact is found re- 
 
 * J. B. Farish, "On the Ore-Deposits of Newman Hill." Proceedings Colorado 
 Scientific Society, vol. iv., and James F. Kemp, Ore-Deposits of the United /States, 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 61 
 
 
 spectively in a crystalline lime, overlain by black shale and un- 
 derlain by sandstone ; in a lime-breccia, underlain by sandstone 
 and underlain by a gray limestone ; and in the third instance 
 
 Fig. 40. 
 
 Sandstone 
 
 Black Selvage 
 FACE OF A STOPE ON THE CONTACT 
 
 in a mass ot crushed quartzose lime, covered by black shale 
 and overlying a blocky limestone. Additional sections are now 
 given in Figs. 39, 40 and 41. In the first of these we see the 
 stringers thrown out by the Enterprise vein as it nears the con- 
 tact, which in this case consists of brecciated lime, enclosing a 
 low-grade quartz ore. In Fig. 41 another similar example is 
 
62 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 given. In Fig: 40 the contact-ore lies at the base of a bed of 
 gypsum, which in turn overlies limestone, penetrated by string- 
 ers, which come from the Jumbo No. 3 vein below. 
 
 The ore of the contact cannot be said to be confined to any 
 
 particular encasement; but one may venture the generalization 
 that it is to be sought for in a layer of crushed rock, which 
 occurs along a certain horizon marked by a thinly-bedded series 
 of black limestones and shales. The parts of the contact ex- 
 plored during my period of management were very frequently 
 characterized by a distinct breccia made up principally, but not 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 solely, of lime-fragments. Pieces of shale and sandstone were 
 recognizable as derived from adjacent beds ; and fragments of 
 porphyrite were traceable to neighboring intrusions of that rock. 
 The contact above the Jumbo "No. 2 frequently consisted of 
 compact, pulverulent lime, graduating into breccia overhead and 
 underlain by blocky lime ; that above the Enterprise was often 
 breccia, shading off into blocky lime overhead, and underlain 
 
 Fig. 42. 
 
 <7 . . 
 
 ff ** - i^3 "Q -/ jy -f7 *-- 
 
 
 :i, Breccia; b, Crushed Lime and Quartz; c, Lime; d, Laminated Lime; 
 
 e, Sandstone; /, Blocky Lime. 
 
 A BARREN CONTACT. 
 
 by black shale ; while the ore of the Jumbo ~No. 3 contact was 
 found between a powdery brown lime and a thin bed of black 
 shale. The variability of the stratigraphical position of the ore, 
 thus emphasized, is due to the non-persistence of individual 
 beds. 
 
 Except when it tops the veins, the contact is barren. Fig. 
 42 illustrates the face of a cross-drift on the contact where no 
 veins have enriched it. In Fig. 43 an intrusion of porphyrite 
 is shown. The pulverulent lime indicates crushing, probably 
 accompanying the invasion of the porphyrite. 
 
 The crystalline limestone of many sections is doubtless breccia 
 consolidated by pressure and cemented by the underground 
 
64 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 waters which have lined the cavities with crystals of calcite. 
 The gypsum bed to be seen in the southwestern part of the 
 
 Fig. 43. 
 
 f- -j- -j- Porphyrite 
 
 Black Shale 
 
 Brown Purverulent Lime 
 
 Ore and Quartz 
 
 SECTION ABOVE THE JUMBO No. 3. 
 
 Limt 
 
 mine affords a parallel instance. A section is given in Fig. 
 40. The vein whose shattered termination is to be seen below 
 the ore of the contact is the Jumbo ~No. 3. The gypsum thins 
 
THE ENTERPRISE MINE, RICO, COLORADO. 65 
 
 out and is a local occurrence having a maximum thickness of 
 15 feet. Its wavy, compact texture suggests an origin by a sul- 
 phatization of lime-breccia through the agency of solutions com- 
 ing from neighboring ore-bearing measures.* 
 
 The foregoing general description will assist the reader's un- 
 derstanding of Fig. C, which represents a part of the workings 
 on the main (also called the Enterprise) level, 98 feet above the 
 Group tunnel. It covers an area about 1800 feet long by 350 
 feet wide, and was chosen for especial examination and study 
 because the developments are more complete than in any other 
 part of Newman hill, while at the same time they present fea- 
 tures sufficiently typical of the ore-occurrence over the whole 
 territory covered by the mine maps. 
 
 The levels are seen to follow three veins, the Enterprise, Song- 
 bird and Hiawatha, the dip of which is indicated by the arrows. 
 Commencing at the crosscut from the Enterprise shaft the En- 
 terprise vein is followed without difficulty as far as Raise 6,f 
 where the vein dies out in weak stringers. Up to this point 
 the stopes extended to the contact; but northward, stoping 
 ceases on this vein. The vein which the level followed further 
 on, from R8S, was once considered the Enterprise because of 
 imperfect observation of the facts. So also the vein followed 
 by the level further north still, from R15E to R18E, is called 
 the Enterprise. It is a branch vein, a subordinate member of 
 the series of many disclosed in the mine. 
 
 There is too frequent a tendency in mining to look upon 
 veins as necessarily continuous, and to make the nomenclature 
 correspond to the drifts. In this case, a level follows three dis- 
 tinct veins in different parts of its length. The crosscut be- 
 tween R7JE and R8S was put out to search for the Enterprise 
 vein in case it had been faulted by the two cross-veins, G and 
 H. It proved that this particular vein had ceased ; but it led 
 to the discovery of the Kitchen lode. 
 
 The numerous cross-veins are mapped, and their dislocating 
 influence on the pay-veins is easily discernible. 
 
 * A large body of gypsum also occurs along the contact in the Vestal workings 
 of the Rico- Aspen mine. 
 
 f The raises are numbered and initialed, so that E6E means Kaise No. 6 on the 
 Enterprise, E10H, Kaise No. 10 on the Hiawatha, etc. 
 
 5 
 
66 
 
 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 Returning to the crosscut from the Enterprise shaft, we will 
 follow the Songbird, which there appears as a small vein having 
 
 a slight easterly dip. Going northward (to the right), the level 
 shows it to flatten. The next time it is seen, 560 feet further 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 67 
 
68 
 
 north, it has changed its dip strongly westward. The cross- 
 veins, G and H, fault it, and it appears in the Enterprise drift 
 at R8S. The cross-vein K throws it 19 feet eastward, and it 
 is then seen at intervals in cross-cuts and raises until, beyond 
 B17E, at the crosscut to the Laura shaft, it merges with the 
 branch-vein, sometimes labelled the Enterprise. The Hiawatha 
 is disturbed by the same series of cross-veins, and in one case 
 suffers a very serious dislocation, namely, between R9H and 
 B11H, as already described in the discussion of Fig. 23. 
 
 These veins were followed by raises and stopes to the contact 
 overhead, and upon the contact ore-bodies were found having a 
 narrow width and courses corresponding to the strike not only 
 of the pay-veins, but also of the cross-veins. Thus both series 
 of veins, older and younger, rich and poor, are topped by bands 
 of ore distributed along this horizon, so as to make a network 
 the intricacy of which for a long time obscured its real charac- 
 ter. The map exhibits the contact ore-bodies and proves very 
 clearly their connection with the two series of veins. The two 
 sections, along XY and PQ, will further help to explain this. 
 
 Thus it became evident, after careful surveys and the pro- 
 jecting of the dip of the veins to their intersection with the con- 
 tact, that no ore occurred upon that contact which was not re- 
 lated to the underlying veins, and that the latter, conversely, 
 were always topped by ore, although that ore was not necessa- 
 rily always wide enough and rich enough to exploit. 
 
 The geological relationship was abundantly proved ; and 
 when the writer prepared this map by first putting the veins as 
 the surveys had traced them, and then platting the ore-bodies 
 of the contact as the stopes had exposed them, it was very re- 
 markable to discover how the latter corresponded with the pro- 
 jections of the former. 
 
 Fig. D is a longitudinal section along one of the pay-veins, 
 showing how the ore ceases at the contact, and how the stopes 
 extend only a short depth below. 
 
 Fig. E is a section along the Group tunnel, affording an illus- 
 tration of the series of pay-veins and their relation to the con- 
 tact. 
 
 VII. ORIGIN OF THE ORE-DEPOSITS. 
 The structure and composition of the ore-deposits of New- 
 
THE ENTERPRISE MINE, RICO, COLORADO. 
 
 69 
 
 I 
 
 $ 6 
 f I 
 
 i I 
 
 ! 
 
 I '' 
 
 i] 
 
70 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 man hill offer suggestions of their origin. Reference has 
 already been made to the slow recognition of their true rela- 
 tions which came in the wake of extended mine-exploration. 
 When the connection between the flat ore-bodies of the contact 
 and those of the vertical veins underneath them was first traced- 
 there arose the idea that the ore of the former had " spilled 
 over " into the latter ; in other words, the theory of descending 
 solutions was advocated. Such ideas were expressed by some 
 of the experts who testified during the long litigation between 
 the Enterprise and Rico- Aspen companies. All the available 
 evidence on the subject, however, both geological and chemical, 
 is opposed to this view. 
 
 The rocks enclosing the ore-deposits have undergone suc- 
 cessive rupturing, resulting in the creation of a series of frac- 
 tures which have served as water-ways available for the circu- 
 lation of mineral-bearing solutions. The fact that the ore-bearing 
 verticals penetrate the porphyry, and the shattered condition of 
 the latter along the horizon of the contact, prove that its intru- 
 sion among the sedimentary rocks preceded the formation of 
 the ore-bearing fissures. The crossings of the later systems of 
 fissuring establish their relative age. Thus, then, we have evi- 
 dence that a condition of strain culminated in a multiple frac- 
 turing of the Carboniferous rocks, and the formation of certain 
 of these fractures was accompanied pari passu by the slow up- 
 welling of mobile igneous matter which, when cooled and 
 solidified, became the porphyrite of to-day. Outside the area of 
 the mine-workings large faults and enormous intrusions of por- 
 phyrite did occur, but within the region of ore-deposition the 
 forces at work produced a system of small multiple fractures 
 and did not permit the invasion of large masses of porphyry. 
 These results are vaguely ascribed to a condition of strain, and 
 the analogy of other better known regions permits us to 
 ascribe this strain to a local manifestation of that wider phe- 
 nomenon called the continental uplift, itself a part of the read- 
 j ustment of the earth's exterior to a shrinking interior. 
 
 During the next disturbance of equilibrium, a disturbance 
 probably due to the contraction following upon the cooling of 
 the included masses of porphyrite, a set of new fractures was 
 formed 7 and along these underground waters began to move. 
 When they had precipitated valuable ores along their channels 
 
THE ENTERPRISE MINE, RICO, COLORADO. 71 
 
 of circulation, later movements produced a series of cross-frac- 
 tures which faulted them. Minor shiftings, which have super- 
 vened at various more recent times, have caused displacements 
 along the bedding, affecting hoth of the older vein-systems. 
 
 The contact-zone has been the victim of all these disturbances. 
 This is to be ascribed directly to its structure. A thickness of 
 closely-laminated shales is laid upon blocky limestones and 
 sandstones. To the formation of a fracture the latter rocks 
 would offer no particular obstacle, because of their homogeneity ; 
 but the upward extension of a fracture would be impeded, if 
 not stopped, by meeting a series of beds which, on account of 
 their laminated structure, are easy to bend, but hard to break. 
 There is nothing fanciful in this reasoning. The section given 
 in Fig. 19 affords an illustration exactly in point. Thus, it 
 seems to me, the structure of the rocks of the horizon now 
 known as the " contact," was the immediate cause of the re- 
 peated shattering which that horizon underwent ; it was the fac- 
 tor which stopped the upward extension of the vein fractures 
 and produced the consequent limitation to the circulation of those 
 mineral solutions which were the immediate agents of ore-de- 
 position. Thus is explained the concentration of large masses 
 of ore along this zone, because it became a dam, checking the 
 circulation in an upward direction. The fractures now followed 
 by the pay-veins were unable to break through the shales above 
 the contact, and though the later cross- veins were stronger, 
 they too were stopped by the elasticity of these closely-laminated 
 beds. 
 
 In each case, therefore, the force of vertical fracturing was 
 diverted into a horizontal displacement which soon made the 
 zone under the shales a mass of shattered rock, peculiarly 
 adapted to become the place of ore-deposition. 
 
 The ore is confined to the pay-veins for a depth of 100 to 175 
 feet below the contact. It does not occur in the cross-veins, but 
 is found in the contact immediately above them, as above the 
 pay-veins. This distribution cannot be satisfactorily explained 
 with positive certainty. There are so many conditions deter- 
 mining the character of an ore-deposit, and ordinary mine- 
 exploration, being a commercial enterprise and not a scientific 
 inquiry, reveals so few of them, that the geologist, though aided 
 by the chemist, is often at a loss. Yet, in this case, the avail- 
 
72 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 able evidence, though in many ways inconclusive, is highly 
 suggestive. 
 
 The ore-bodies of the contact apparently owe their existence 
 to a combination of chemical and physical conditions. The 
 ending of the vein-fractures at the contact-horizon put a stop to' 
 the upward flow of the metal-bearing solutions, and caused them 
 to permeate the shattered rock and distribute themselves along 
 the strike of the veins which had been their passage-way. At 
 the contact they found the chemical precipitant which com- 
 pelled the dissolved metals to separate out as aggregates of ore. 
 That precipitant was probably the graphite of the black shales, 
 as is indicated by actual experiments presently to be described. 
 
 The non-persistence of the ore of the pay-veins below a cer- 
 tain distance from the contact is apparently connected with the 
 circumstance that the sedimentary rocks immediately below the 
 contact are black, by reason of the carbonaceous residues of the 
 vegetation imbedded amid the sand and mud on the floor of an 
 estuary of the Carboniferous period. This carbonaceous matter 
 probably acted as a precipitant of the metal-bearing solutions. 
 As the depth below the contact increases, the rocks lose their 
 blackness, and presumably, therefore, contain no precipitant 
 carbon. 
 
 Although the pay-ore terminates at a depth fairly uniform 
 among the different veins, it must not be supposed that the 
 veins themselves cease at this horizon. On the contrary, the 
 fractures maintain their course to depths far beyond the deepest 
 mine-workings; but they become barren of valuable ore, en- 
 closing nothing but quartz and crushed country. The rhodo- 
 chrosite ceases. The Lexington tunnel, for example, cuts 
 through the lodes which have yielded so richly in the Enter- 
 prise workings, 400 feet overhead, and discloses them as veins 
 of white quartz, traversing light gray, coarse-grained sandstone. 
 Both lode and country-rock have changed in character entirely. 
 
 The fact that the cross-veins are barren, and yet rich ore- 
 bodies overlie them in the contact-zone, indicates that such 
 bodies are due to special shattering of the ground by the cross- 
 veins, which has furnished favorable places for ore-deposition. 
 Moreover, barren as the cross-veins are, they appear to influ- 
 ence the richness of the pay-veins. It is common to find ores 
 of more than average grade in the pay-veins, where they are 
 
THE ENTERPRISE MINE, RICO, COLORADO. 73 
 
 broken by the cross-veins. But the mineral solutions appa- 
 rently did not rise through the cross-veins. They must have 
 circulated along the verticals ; and the deposition of ore in con- 
 nection with the cross-veins, as noted, may have been not only 
 a collateral, but even a secondary process. The superior rich- 
 ness of these bodies in many cases may indicate that they have 
 resulted from a re-solution and re-deposition of the contents of 
 the verticals. 
 
 The idea of the precipitation of the ore through the agency 
 of carbonaceous matter has been advanced in connection with 
 ore-deposits in other regions. I may quote as instances the 
 black Silurian slates of Bendigo, Victoria;* the Devonian 
 slates of Grympie, Queensland; the Jurassic slates of the 
 " mother lode " region in Calaveras and Amador counties, Cali- 
 fornia; the black shale enclosing the gold-specimen ores of 
 Farncomb Hill, Breckenridge, Summit county, Colorado ; the 
 graphitic casing occasionally seen in the ores of the Sunnyside 
 and Mastadon veins, in v San Juan county, Colorado; and 
 the celebrated Indicatorf series of Ballarat, Victoria. 
 
 In order to test this theory, I broke some pieces of black 
 shale on the contact above Raise 12 on the Enterprise vein, and 
 took tHem to the Argo smelter, where, by the kindness of Mr. 
 Pearce, the following experiments were made. A piece of the 
 Rico shale was put into a weak solution of sulphate of silver 
 (AgSO 4 ) containing some free acid intended to neutralize the 
 lime (CaCO 3 ) in the shale. The precipitation of metallic 
 silver became visible in three days. The parallel experi- 
 ment with gold was more interesting. A piece of ore (as- 
 saying 1147 ounces of gold per ton) obtained from the Prince 
 Albert mine at Cripple Creek was taken, and its gold was ex- 
 tracted by a solution containing ferric sulphate (Fe 2 O 3 3SO 3 ), 
 common salt (XaCl) and a little free acid (H 4 SO 4 ). This Crip- 
 ple Creek ore carried the black oxide of manganese (MnO 2 ) 
 in visible quantity, and thus the chlorine used to form the gold- 
 solution was liberated in a manner simulating natural condi- 
 tions. Of the gold in this Cripple creek ore, 99.91 per cent. 
 
 * Discussed by the writer in Trans., xxii., 319 et seq. Also by Mr. Argall, 
 same volume, p. 762. 
 
 f See also "The Indicator Veins, Ballarat," by the writer, Eng. & Min. Jour., 
 Dec. 14, 1895. 
 
74 THE ENTERPRISE MINE, RICO, COLORADO. 
 
 was extracted, and subsequently precipitated on the Rico 
 shale by inserting the latter in the solution thus formed. The 
 gilding of the black shale by the deposit of gold became visible 
 within four hours. 
 
 The order of succession of the various minerals composing 
 the ore is indicated in many ways. Beautiful pseudomorphs 
 of quartz after baryta have been found. The replacement of 
 rhodochrosite by quartz is often discernible. That the baser 
 sulphides frequently enclose fragments of rhodochrosite (Fig. 
 25), establishes their relative age. Pieces of country found 
 within the vein-matter are occasionally surrounded by a rim of 
 rhodochrosite. (See Fig. 34.) The silver sulphides, and the 
 native gold associated with them, occur exclusively within the 
 geodes which are usually distributed along the center of the 
 vein. The veins enclose shreds of country-rock; sometimes 
 such pieces of rock are found within masses of sulphide ore, 
 and there is an imperceptible graduation from clean sulphide to 
 rock so impregnated with ore as to have its true character ob- 
 scured. Banded structure is common. 
 
 This succession points to the following conclusions : When 
 the fractures were first formed they consisted of lines of 
 crushed c6untry, afterwards healed by a deposit of carbonate 
 of manganese. The latter (rhodochrosite) is likely to have 
 been derived from limestones occurring at a horizon not neces- 
 sarily very far below the place of the present ore-deposits. 
 Then came a fresh fracturing, accompanied by the deposition 
 of baryta and the sulphides of lead and zinc. Later still the 
 earlier vein-stuff became shattered by fissuring on the old 
 lines of movement, and along the water-way thus created there 
 came siliceous solutions, which replaced baryta and rhodochro- 
 sites with crystalline quartz. Finally, the vein was riven 
 along its center, and waters rich in the salts of gold and silver 
 found their way upward to undergo precipitation through the 
 agency of the rhodochrosite and the shattered portions of the 
 carbonaceous country enclosed within the vein-walls. 
 
 We are driven in this case to the hypothesis of ascending 
 solutions. A lateral flow must be a part of an upward or down- 
 ward movement of the underground circulation. As a general 
 phenomenon it is inconceivable. The deposition of ore from 
 descending solutions is in this case chemically possible through 
 
THE ENTERPRISE MINE, RICO, COLORADO. 75 
 
 the reduction of sulphates by carbonaceous matter. But for 
 the hypothesis of descending sulphates there is no basis of fact. 
 The geological evidence is all against it. The structure and 
 environment of the ore-bodies point to their derivation from 
 solutions which came up from below. The passage-ways open 
 to the circulating waters cease upward and extend downward ; 
 they connect with no available origin in one direction, but lead 
 to a possible source in the other. 
 
\v 
 
 Subject to Revision. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 TEE MOUNT MORGAN MINE, QUEENSLAND. 
 
 BY T. A. RICKARD, MELBOURNE, AUSTRALIA. 
 
 (Cleveland Meeting, June, 1891.) 
 
 AMONG the gold-deposits discovered in recent years none is more 
 extraordinary in richness or interesting in structure than that of the 
 famous mine at Mount Morgan. At a time when but few Aus- 
 tralian mines were known to the world outside the colonies, Mount 
 Morgan was quoted as an occurrence, unusual not only in its origin 
 (for it was said to be due to geyser-action) but also in the purity of 
 its gold. 
 
 The mine is situated just within the tropics, twenty-six miles 
 southwest of Rockhampton, in central Queensland. Queensland 
 attained in 1889 the first place among the gold-producing colonies 
 of Australasia, a position previously always held by Victoria. In 
 that year Queensland produced 737,822 ounces, while Victoria came 
 second with 614,838 ounces. Of the four chief mining districts 
 Rockhampton stood first, as the following figures show: 
 
 Quartz crushed, Yield, Average per ton, 
 
 
 Tons. 
 
 Ounces. 
 
 Oz. Dwt. 
 
 Rockhampton, 
 
 . 81,138 
 
 340,669 
 
 4 2 
 
 Charters Towers, . 
 
 . 109,328 
 
 165,551 
 
 1 10 
 
 Gympie, 
 
 . 106,625 
 
 112,847 
 
 1 1 
 
 Croydon, 
 
 . 29,423 
 
 51,156 
 
 1 15 
 
 It should be added that Queensland has but little alluvial mining, 
 the total output from this source in 1889 being only 5044 ounces, 
 none of which came from the four principal gold-fields. Leaving 
 out Rockhampton, the output of which is practically that of the 
 Mount Morgan mine, it will be noted that the more northerly gold- 
 fields show the highest average (Gympie being furthest from and 
 Croydon nearest to the equator). This is largely explained, how- 
 ever, by the increased cost of milling, due chiefly to the want of 
 water for batteries and the consequent economical necessity of select- 
 ing high-grade material only for crushing. 
 
 During the year ending November 30, 1889, the Mount Morgan 
 
2 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 mine produced 75,415 tons, yielding 323,542 ounces, 13 dwts., 13 
 grs., worth 1,331,484 18s. 5d. (about $6,657,424), while the ex- 
 penditure was 227,769 19s. Sd. (say $1,138,849) permitting the 
 payment of 1,100,000 ($5,500,000) in dividends. The yield per 
 ton was 4 oz., 6 dwts., 4 grs., while the working-cost was, as is seen, 
 only 17 per cent, of the value of the product. These figures speak 
 for themselves. 
 
 So rich a mine would be expected to have some romance woven about 
 the story of its discovery. Numerous and various tales are told of 
 the first recognition of its value, but the best authenticated facts are 
 as follows : The property consists of the original selection (No. 247) 
 of 640 acres taken up for grazing purposes, in 1873, by Donald 
 Gordon. Becoming acquainted with the brothers Morgan, who also 
 held land in the district, he showed them one day a piece of gold- 
 bearing quartz which he had picked up in Mundic creek. For a 
 consideration, stated to have been 20 and as much whiskey as he 
 could drink, Gordon agreed to indicate to them the locality of the 
 find. On the hill overlooking the creek he showed them the siliceous 
 ironstone, some of which can still be seen cropping out on the north- 
 eastern slope. The stone carried visible gold ; they found by send- 
 ing samples to Sydney that it was even richer than they had imagined ; 
 so they purchased Gordon's holding at 1 per acre. 
 
 The three Morgans subsequently sold, first a part, and eventually 
 the whole, of their interest in the mine. In 1886 a company was 
 formed with a capital of one million shares of 1 each. These shares 
 rose toward the end of 1888 to 17 5s. (about $86.25) giving the 
 mine a market value of seventeen and a quarter millions sterling or 
 over eighty-six million dollars. The shares are now quoted at 7; 
 for Mount Morgan, to quote the language used by the managing 
 director at an annual meeting, " is after all only a gold-mine and is 
 consequently subject to the vicissitudes of all mineral formations," 
 which is a truism too often forgotten by those who conduct mining 
 operations.* 
 
 DESCRIPTION OF THE MINE. 
 
 The mine does not, as its name would imply, crown the summit 
 of a mountain, properly so called, but forms a quarry at the top of a 
 
 * Of the neighboring companies (and as might be expected they are numerous, 
 with their suggestions of an extension of the ore-deposit in such names as Mount 
 Morgan West, Mount Morgan Extended, Mount Morgan North Consols and so on ad 
 nauseam) none have proved profitable, notwithstanding the expenditure of much 
 money in numerous and scattered trial-shafts, tunnels, etc. 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 3 
 
 hill, only 500 feet above the village at its base and 1225 feet above 
 sea-level, surrounded by very broken hilly country and almost 
 encircled by a small stream (the Mundic creek already mentioned), 
 and in many respects distinct in position and geological structure 
 from the hillocks about it. From the summit can be seen the level 
 line of the " desert sandstone/' crowning the highest ridges of the 
 neighboring hills spurs from the main range which under different 
 names (Blue Mountains in New South Wales and Australian Alps 
 in Victoria) traverses the three colonies near the east and south- 
 eastern coast of the Australian continent. The base of the sandstone 
 is slightly lower than the summit of Mount Morgan and overlies 
 greywacke and quartzite. Dykes, of at least two periods, form an 
 important feature of the structural geology. 
 
 The crest of the mount is being rapidly broken away in the quarry- 
 ing operations which have supplied the great output of the mine. 
 The removal of from 1200 to 1700 tons a week makes a big hole in 
 a year. While the greater part of the summit has been thus re- 
 moved, the northeast slopes still show the croppings which first ex- 
 cited Gordon's attention. 
 
 The ground is worked in terraces or benches, 30 feet high and 300 
 feet long. At the date of my visit five of these, started at various 
 times, could be seen, though but little remained of the floor, 25 feet 
 from the top, which formed the open cut first put into the ore. A 
 central shaft passes from the floor of the second terrace and connects 
 with the deeper tunnels, a series of which have intersected the deposit 
 in various directions. This shaft, at 206 feet, connects with the 
 Freehold tunnel, the main ore-way of the mine, which is 789 feet 
 long. The next deeper tunnel, called No. 1, starting at right angles 
 to the Freehold, from the southern face of the hill and penetrating 
 it for 1070 feet, is 155 feet below the floor of the lowest surface- 
 working and 320 feet below the original summit. This No. 1 
 tunnel, though only 33 feet deeper than the Freehold, affords a very 
 interesting section of the mountain and indicates a great change in 
 the form of the ore-deposit. It is the deepest of the adits (for adits 
 and not strictly tunnels most of them are), except the "Sunbeam," 
 which had been started at the time of my visit; but it had not been 
 advanced sufficiently to throw any additional light upon the struc- 
 ture of the mountain. 
 
 The Mount Morgan ore is remarkable for its extremely hetero- 
 geneous character. The frequent alleged discoveries of " a second 
 Mount Morgan," supported by similarity of the specimens exhibited 
 
4 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 to specimens of the Mount Morgan ore, are not to be wondered at, 
 in view of the great difference in appearance of fragments broken in 
 different parts of the same heading of this mine. The material 
 quarried in the upper workings, samples of which are now to be 
 found in collections and museums all over the globe, is generally so 
 friable and shattered, as to render its removal with the aid of black 
 powder only, very easy. Standing in one of the open cuts, one can 
 see faces of bluish-gray crushed quartz very similar to Comstock 
 ore ; masses of siliceous hematite (usually considered the most typical 
 Mount Morgan stone) resembling the croppings of ordinary gold- 
 veins, whether in Victoria or California; heavy black iridescent 
 iron-stone which might be the cap of a silver-lode; and light- 
 colored reddish ore which might come from the gossan of a copper- 
 mine. Some of the material is crushed to the consistency of sugar, 
 while in other portions of the mine men are seen employed in break- 
 ing boulder-like masses of ore. Stalactitic forms occur in cavities, 
 whilst a vermicular and reniform appearance is also not uncommon. 
 Very rich returns were obtained from a body of bluish-black, beau- 
 tifully iridescent ore. The Freehold tunnel-workings encountered 
 a patch of very pure white, porous, friable " sinter," so light, owing 
 to the imprisoned air, that it would float on water. 
 
 Mount Morgan is not a "specimen-mine/' though in its early 
 history it furnished very lovely pieces of gold-quartz, some of which 
 I saw in Sydney. They consisted of an iron gossan, containing big 
 "splashes" of gold, of the size of a thumb-nail. As a rule, how- 
 ever, the gold, even when visible, is very fine and scattered thickly 
 through the stone ; but owing to its peculiar character (the coating 
 of oxide of iron to be referred to later on) it is not readily detected 
 by the eye. 
 
 Examination of the many varieties of ore shows that while there 
 may be a great difference in outward appearance, due to coatings of 
 many-colored oxides, the ore is always substantially quartzose. As 
 seen in the surface-workings, the deposit may be considered a mass 
 of quartzose material of varying color and specific gravity, traversed 
 by a series of dykes having a general N. W. and S. E. direction. 
 Its extent is approximately indicated by the various workings which 
 intersect the hill. In the upper part of the mine, while the north 
 and northeastern slopes prove it to be continuous in these directions, 
 its eastern limit has been reached in the lower floors or benches ; and 
 to the southwest it is bounded by a large felstone dyke, which forms 
 the most marked feature of the surface-excavations. The first 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 5 
 
 tunnel to pierce the hill is No. 2, which starts from the fifth or 
 lowest floor, running N. 10 E. and penetrating 120 feet of ore before 
 it reaches a dyke. This is probably the dyke above mentioned 
 as the boundary of the deposit in the upper floors; but here it has 
 evidently cut into the deposit. Beyond this dyke the tunnel is in 
 ore for 200 feet further, before meeting another intrusion of felsitic 
 matter, which extends for the remaining 130 feet to daylight. A 
 branch-tunnel proves the continuity of the ore-body eastward. At 
 this level the stone evidently holds out most satisfactorily, and is, I 
 believe, for the most part auriferous. It is a porous siliceous mate- 
 rial, varying between a light "sinter" (sometimes white, sometimes 
 iron-stained) and a heavy iron-stone, often manganic, the latter in 
 boulder-like masses. 
 
 The next tunnel is the Freehold, forming, as has been said, the 
 main artery of the mine. It connects with the shaft (sunk from the 
 No. 2 floor), and from the mouth of it a tramway carries the ore to 
 the chlorination-works. The tunnel starts from the southeast face 
 of the hill, traversing a decomposed rhyolite for the first 180 feet, 
 and then cuts through 40 feet of pyritiferous quartzite, a rock which 
 here first makes its appearance and which will be seen to play an 
 important part in the geology of the locality. Leaving the quartzite, 
 the tunnel cuts through 180 feet of a rock which I recognize* as a 
 normal dolerite. The innermost portion is decomposed, and abuts 
 against a much altered felspathic rock. This brings us to 390 feet 
 from daylight ; the remainder of the tunnel (397 feet) traverses the 
 ore-deposit. The ore is a light sinter-like quartz, often iron-stained ; 
 but while it contains short rich patches the general tenor is low. 
 Near the junction with the main shaft, almost at the end of the 
 tunnel, a branch cross-cut runs southward for 237 feet. The first 
 J86 feet are in the deposit, which here also is poor, though in ap- 
 pearance it does not differ from the richer portions. f The next 20 
 feet traverse the dyke which at this point, as in the upper floors, 
 forms the limit of the ore-body. Beyond this there is only to be 
 seen the pyritiferous quartzite, which also appears in a short cross- 
 cut to the east. 
 
 The next deeper tunnel is Xo. 1, only 33 feet below the Freehold. 
 I was denied access to this, and am, therefore, indebted to a govern- 
 
 * Thanks to microscopic sections shown to me at Charters Towers by Mr. Clarke. 
 f It is here that one sees the light, white, pumice-like material which, owing to 
 the air in its cavities, will float on water. 
 
6 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 ment report* for the following particulars : This adit, 1070 feet lon<r, 
 starts in, and traverses, the quartzite of the country for 132 feet before 
 passing through a narrow dyke; it then passes through 67 feet more 
 of highly pyritiferous quartzite, which continues to within 12 feet 
 of a shaft coming down from floor No. 5. There next succeeds a 
 large felstone dyke (the one noted as cut in the tunnel above), and 
 the remainder of the adit continues in pyritiferous quartzite, alter- 
 nating with numerous dykes, until the last 200 feet are reached, 
 which are occupied by an altered dolerite. The auriferous material 
 of the upper workings was represented in this adit by 25 feet only 
 of siliceous iron-stone. Two branch cross-cuts similarly prove the 
 absence of the deposit in this part of the mine at this depth, as they 
 also intercept the quartzite of the country. 
 
 A still lower tunnel, the Sunbeam, starts from the west face of the 
 mountain, passing through pyritiferous quartzite; but it was not 
 advanced sufficiently at the time of my visit to afford any evidence 
 as to the extent of the ore-deposit. 
 
 It will be noted that the largest section as yet obtained of the 
 auriferous portion of the deposit is in tunnel No. 2, where its dimen- 
 sions are 356 feet (26 feet of which is occupied by the big dyke) ii> 
 a north direction, by 310 feet east, as proved by a branch cross-cut. 
 The deposit has been proved to extend further eastward in the deeper 
 levels (Freehold tunnel) than it did in the surface-excavations, while 
 on the other hand its western limits are more restricted. 
 
 THEORIES OF THE FORMATION OF THE ORE-DEPOSIT. 
 
 The origin of the ore-deposit has been, as might be expected, the 
 theme of much controversy. The earliest description came from Mr. 
 R. L. Jack, the head of the Queensland geological survey, well 
 known as a careful observer. His report was made officially for his 
 government and appeared in 1881. Others have contributed their 
 opinions since; and meanwhile the rapid development of the mine,, 
 more particularly by the deeper adits, has furnished additional data 
 for a problem, of which the following solutions have been offered : 
 
 1. That the deposit is that of a geyser (R. L. Jack). 
 
 2. That it is an auriferous zone traversed by a series of quartz 
 veins of auriferous rnundtc (J. Macdonald Cameron). 
 
 3. That it is the decomposed cap of a large pyrite-lode (the view 
 held by several local and other mining engineers). 
 
 * R. L. Jack's second report, which will be referred to again. 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 7 
 
 The Geyser- Theory. The first of these explanations, known as the 
 "geyser-theory," was promulgated by Mr. Jack in his first report, 
 dated November 8, 1884. It has found its way into many scientific 
 publications, and has been until recently the most widely accepted. 
 Citing as a similar occurrence the hot springs and geysers of the 
 Yellowstone Park, described by Dr. A. C. Peale in the United States 
 Geological Survey reports, Mr. Jack observes in his first report: 
 u Nothing but a thermal spring in the open air could have deposited 
 the material under consideration." The two sections shown in Figs. 
 1 and 2 are taken from that report. Of Fig. 1, he says: "The 
 above diagram represents my idea of what would take place in the 
 case of a geyser remaining in activity for a (geologically speaking) 
 lengthened period." The original form of the ground is shown by 
 aa, the deposit of precipitated material by 66, the layer of solid 
 material at cc, while the surface-contour is indicated by dd. In de- 
 scribing this section he concludes, "Such, I believe, is the history of 
 Mount Morgan as we now see it." 
 
 The structure of the mountain is supposed to be shown by Fig. 2, 
 in which Mr. Jack indicates rhyolite dykes at d and metamorphic 
 rocks at s. He says : "a is the pipe of the geyser (theoretical), 6 
 the cup-deposit and c the overflow of the geyser." 
 
 These two sections have found their way into scientific publica- 
 tions all over the world, and have been for a long time accepted as 
 most interesting explanations of one of the richest of modern gold- 
 mines. But they evidently are altogether imaginary and theoretical. 
 
 The same geologist says, in his description: "After the cessation 
 of thermal activity the powers of sub-aerial denudation would come 
 into play. Denudation would obliterate the lateral terraces which 
 were probably not absent from the slopes of Mount Morgan." The 
 information obtainable in 1884 as to the nature of the deposit was 
 totally insufficient to enable an observer, however careful and ex- 
 perienced, to build a theory upon. The amount of work done at 
 that time was mostly limited to one open cut, 10 by 15 feet in size, 
 which showed a fan-like arrangement of the ore, suggesting to Mr. 
 Jack the structure of a geyser. It was an altogether local appear- 
 ance, as was proved by the work of a few days later. 
 
 In a second report, dated December 12, 1888, Mr. Jack adds: 
 " The evidence now to hand, in my opinion, goes far to confirm my 
 original view that the auriferous material was deposited by a thermal 
 spring." The deposit had been asserted in the first report to have 
 been formed " in the open air," a condition constituting the whole 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 \ WA 
 
 ' , -b 
 
 \ / / N N 
 
 N - v/ ; A\ N ^ 
 
 .2> Mvx // / ; is N 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 9 
 
 distinctive value of the theory, which otherwise might not differ 
 materially from the views accepted as to the aqueous origin of ore- 
 deposits in general. In the second report the author declares his 
 theory to have been confirmed, but produces evidence which really 
 contradicts its essential feature. 
 
 Taking the two reports together, we find that, in support of his 
 explanation, Mr. Jack adduces: (a) the "fan-like arrangement" of 
 the material ; (6) " the frothy and cavernous condition " of the 
 siliceous sinter; (c) the hydrated condition of the silica and (d) the 
 fact that one of the dykes intersecting the country does not also in- 
 tersect the deposit. 
 
 (a) The u magazine" face, at the time of Mr. Jack's first visit, 
 appeared to him to have a distinctly fan-like structure. But little 
 work having been done since that time at this particular point, it 
 should be possible to verify this statement; but the most careful 
 observation does not confirm it. The cutting shows an arrangement 
 of loose material such as can frequently be seen in surface-excava- 
 tions, probably less marked now than when first seen by Mr. Jack ; 
 but the entire absence of any repetition of such an arrangement of 
 material in the other workings must destroy its value as evidence, if 
 it ever had any. 
 
 (6) The " frothy and cavernous " condition of the quartz is not 
 peculiar to Mount Morgan. Those who are familiar with the 
 pocket-mines of California will remember the very light, pumice- 
 like quartz which often accompanies the gold in those mines. It is 
 the light honeycombed quartz found in the gossan of gold-veins in 
 many places. Generally speaking, the Mount Morgan gangue can 
 be duplicated elsewhere ; and the particularly light " frothy sinter," 
 noticeable as a patch in the deeper workings, differs only from the 
 bulk of the quartzose ore in that it is remarkably free from accessory 
 minerals. It is the siliceous skeleton produced by surface-decom- 
 position of more than ordinary intensity. It is possible to produce 
 artificially in a few minutes, by the application of acid to very dis- 
 similar iron-stone ore, a material similar to that noted, which has 
 undergone the chemical action of underground waters during long 
 periods. 
 
 (c) The hydrated condition of the silica is not unusual in quartz- 
 lodes, and while it is valuable as evidence to disprove the suggestion 
 that the ore is the replacement of anhydrous qtiartzite, it does not 
 necessarily point to the agency of a geyser. 
 
 (d) The intersection of the country by a dyke which does not pene- 
 
10 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 trate the deposit is an important fact. The dyke referred to is that 
 cut by tunnel No. 1 at 120 feet from the shaft coming down from 
 floor No. 5. Mr. Jack says, at the end of the second report : " This 
 shows that the sinter and iron-stone are deposited on, and were not 
 altered portions of, the pyritous quartzite country-rock." Unfor- 
 tunately the evidence is far from conclusive. In describing No. 1 
 tunnel the dyke is referred to in the following sentence: " A quart- 
 zose rock full of fine pyrites is traversed -for the next 37 feet, when 
 a dolerite or rhyolite dyke is cut. The direction of this dyke is un- 
 certain, as the tunnel is here timbered up." In his descriptions Mr. 
 Jack always endeavors to draw a marked distinction between the 
 " felstone " dykes which penetrate the ore and the "dolerite 7 ' and 
 "rhyolite" which intersect the country-rock. Now, this distinction 
 is arbitrary and misleading. I examined the rocks both in situ and, 
 a few days afterwards, under the microscope. The dykes penetrating 
 the deposit are so decomposed that it is impossible now to determine 
 which is felstone and which rhyolite. The dykes cutting through 
 the country are similarly, but not to so great a degree, decomposed, 
 especially in the vicinity of the deposit. The statement that a 
 "dolerite or rhyolite" dyke does not penetrate a deposit which is 
 freely intersected by decomposed felspathic eruptives, should be sup- 
 ported by proof. 14; is not so here; for the dyke cut in No. 1 tunnel 
 has not been followed upward, and in the south branch of the Free- 
 hold tunnel, just overhead, there is a dyke, which is possibly the one 
 in question. 
 
 My sections, shown in Figs. 3 and 4, will illustrate this. The 
 left half of Fig. 4 resembles one of Mr. Jack's sections, being taken 
 along a nearly identical plane (mine is taken due north and south). 
 His section, however, gives a curved contour to the limit of the 
 deposit, very nicely, but unwarrantably, suggesting the shape of a 
 geyser-basin. The right half of the section is not filled in, since 
 this part of the mount has not been thoroughly developed. Fig. 3 is 
 taken along a line E. 17 S., and is obtained by projecting the cross- 
 cuts from the No. 1 and Freehold tunnels upon the plane of the No. 
 2 tunnel. 
 
 In further considering the conditions under which thermal springs 
 and geysers* exist, and the similarity of such conditions to those ob- 
 taining at Mount Morgan, it may be noted: 
 
 1. Isolated geysers are unusual, nothing being more remarkable 
 
 * A geyser may be defined as a thermal spring ejecting material in the open air. 
 
THE MOUNT MORGAN MINE* QUEENSLAND. 
 
 11 
 
 than the exteuded area of such phenomena. But vigorous and ex- 
 tensive prospecting, such prospecting as always follows great min- 
 eral discoveries, has not led in this region to the finding of anything 
 
 similar to Mount Morgan or to a geyser. It is true, there is a small 
 hillock adjoining the mount to the northwest (called Callan's Knob) 
 where somewhat similar material has been found ; but it may be 
 considered as an offshoot or spur from the main deposit. 
 
12 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 2. Geysers have terrace-formations due to the overflow of the 
 siliceous or calcareous waters. The map accompanying Mr. Jack's 
 first report indicated "the overflow from the hot spring" as cover- 
 ing an area of 2000 by 3000 feet. But this was purely a guess, for 
 such overflow-material is not to be seen ; had the terraces existed, 
 and had they been removed by denudation, would not the adjoining 
 river beds show some accumulations of their detritus? 
 
 3. Geysers have a central vent, which, when the geyser becomes 
 extinct, is found to be choked up with sinter. Though Mount 
 Morgan has been traversed by a number of adits and cross-cuts, not 
 to mention extensive surface-excavations, no such vent and no such 
 central column, or anything suggestive of either, has been seen. 
 
 The Network- Theory. The second explanation is that of J. Mac- 
 donald Cameron, namely, that it is a network of quartz veins. This 
 opinion was expressed in a report to the directors of the company, 
 dated March 26, 1887. The following passage outlines the author's 
 ideas: "It (Mount Morgan) may be considered as consisting of a 
 net-work of quartz veins, about 200 feet in width, traversing on the 
 one hand a metamorphic matrix of a somewhat argillo-arenaceous 
 composition, largely impregnated where it has been exposed to at- 
 mospheric influence with oxides of iron, and on the other hand what 
 appears to be a felspathic tufaceous igneous rock/' The author ad- 
 vances no proof that such is the case. What evidence he does give 
 is couched in the vaguest phraseology. This explanation is proved 
 untenable by the same reasons as those which apply to the third 
 theory now to be considered. 
 
 The Lode-Theory. The view that this deposit is the decomposed 
 cap of a pyrites lode, has derived fictitious importance from the fact 
 that it is alleged to be the opinion of the mine-manager and others 
 interested in the property. Such a view has been the excuse for the 
 large number of "extended" companies (they call them "pups" in 
 Victoria), companies which, in the light of our present knowledge, 
 were almost certainly foredoomed to failure. The prevalence of the 
 lode-theory in the early days of mining at Mount Morgan is not to 
 be wondered at, however little warrant there may be for it now. It 
 was due to the existence of mundic veins in the vicinity, the casts of 
 pyrites crystals found in the ore, and the neighborhood of the pyri- 
 tiferous quartzite, the true relation of which was not known, or if 
 known, was kept very quiet. The well-marked limits of the great 
 deposit, as outlined by the deeper developments of the last two years, 
 completely disproves this theory and that of Cameron. No doubt, 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 13 
 
 \ 
 
 the assertion of the continuity of the gold-bearing rock, even though 
 it should become pyritiferous, has fascinations for a shareholder 
 which even a geologist can understand. But the deeper tunnels 
 have proved that lode-structure is entirely absent, and that the de- 
 posit lies upon, but is not an altered portion of, the pyritiferous 
 quartzite of the country. 
 
 The Theory of Metamwphosis and Replacement. The more than 
 ordinary size and value of the Mount Morgan ore-deposit, the ro- 
 mantic history of its discovery and its subsequent marvellous pro- 
 duction, have all helped to place it outside the ordinary type of 
 mineral occurrence. This is often the case with new discoveries, 
 and it is not the first time that the geyser has been a deus ex machina 
 to a perplexed geologist. The splendid work done in recent years 
 by Sandberger, Daubree and others in the study of the chemical 
 change, and the distribution by underground waters, of the minerals 
 of the older rocks has led to a gradual substitution, for theories of 
 eruption, or direct igneous agencies in general, of the belief in the 
 capability of aqueous agencies to bring about most of the phenomena 
 of ore-deposition. Moreover, the action of percolating solutions on 
 the minerals of the crystalline rocks, and subsequent interchange 
 with the more soluble portions of the neighboring rock-masses, have, 
 to a great extent, replaced the assumptions of the old ascension- 
 theories. The view that the more ore-deposits are studied the more 
 frequently they will be found to be in great part the product of the 
 replacement of the country-rock is gaining ground, and has been 
 much strengthened by the researches of Becker at Virginia City, 
 Curtis at Eureka, and Emmons at Leadville, as contained in the 
 monographs published by the U. S. Geological Survey, monographs 
 (the last-mentioned, particularly), which are the classics of modern 
 economic geology. This view, which underground experience is 
 continually confirming, has explained many of the more unusual 
 types of ore-deposition in Europe and America, and I believe it will 
 apply to Mount Morgan. 
 
 The explanation suggested is this : that the ore-deposit of Mount 
 Morgan represents an altered portion of shattered country-rock, 
 which, by reason of its crushed condition, was readily acted upon by 
 mineral solutions, and that these solutions replaced the basic and 
 felspathic with acidic and quartzose material, which was also gold- 
 bearing. It is its quartzose and permeable character which has saved 
 from disintegration the mass thus affected, and has preserved it as 
 an ore-body on the summit of the hill. 
 
14 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 A case, in many respects very similar, occurs in the Red Mountain 
 basin, Colorado, and the following description given by Mr. Em- 
 mons* is clearly in point : 
 
 " Instead, however, of being surface-deposits, they (the Red Mountain deposits) 
 are simply portions of the andesitic country-rock from which acid waters have re- 
 moved the basic constituents, perhaps depositing a certain amount of silica in their 
 place ; the resulting quartzose masses, offering greater resistance to the disintegrat- 
 ing effect of atmospheric agents and to erosion than the surrounding rocks, have 
 been left as mound-like ridges protruding above the general surface, more or less 
 independent of the natural drainage-channels." 
 
 This explanation, curiously enough, was also given to disprove a 
 geyser-theory, but the deposits in question seem to possess scientific 
 interest only. 
 
 Deposits of somewhat kindred origin are the Yankee Girl and 
 Bassick mines in Colorado. The former, a well-known mine in the 
 San Juan district, is perhaps the more suggestive, since in that case 
 several fracture-planes meet to form a wedge-shaped mass of rock, 
 which has been so acted upon by percolating waters as to become a 
 "chimney " of very valuable silver-ore. 
 
 To return to the particular conditions which obtained in the dis- 
 trict under discussion: The country around Mount Morgan consists, 
 in descending series, of sandstone, greywacke, quartzite, shales and 
 occasional bands of serpentine. Intrusive masses of dolerite inter- 
 penetrate the country, and often occupy a position between the 
 originally stratified rocks. The sandstone is known in the geology 
 of Queensland as " Daintree's desert sandstone," and, by virtue of a 
 recent discovery of fossil remains, may be labelled as Cretaceous. The 
 greywacke has not been recognized as such on the Mount itself, but 
 it underlies the sandstone in other parts of the district. It is a mix- 
 ture of silico-felspathic material, which shades off into a grey wacke- 
 slate, and is usually so much altered as to be scarcely distinguishable 
 from a true eruptive. The quartzite has a bluish-gray color, and is 
 highly -pyritiferous, the pyrites carrying traces of gold. 
 
 The shales are usually so indurated and altered as to resemble 
 closely the crystalline rocks. The dolerite", when fresh, is a typical 
 rock of its class, and in various intrusive forms is cut through by 
 most of the prospecting-shafts at the base and around the mountain. 
 The serpentine is of very limited occurrence. Some uncertain, un- 
 determined decomposed rocks, which have also been called dolerite, 
 
 * "Structural Relations of Ore-Deposits." Transactions, xvi., 809. 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 15 
 
 are probably metamorphosed greywacke. The country is freely in- 
 tersected by dykes of varying composition, especially near the ore- 
 deposit. 
 
 The history of these rocks I read somewhat as follows : A period of 
 dynamic disturbance is indicated by the intrusions of dolerite, which, 
 by extreme metamorphism, might have changed a dolomite into the 
 serpentine we now see ; would have indurated the shales so that they 
 are scarcely to be distinguished from the crystalline rocks; and 
 would also, accompanied by chemical alteration, change a ferrugi- 
 nous red sandstone into a bluish-gray, highly pyritiferous quartzite. 
 Approaching the surface, the same energy would be expended in 
 the fracturing of the quartzite and greywacke; the intrusive dolerite 
 would rise through the fissures in the shattered rocks, form ing dykes, 
 which, meeting a silico-felspathic granular rock (the greywacke), 
 would give it a semi-crystalline character. The sandstone would 
 similarly be vitrified. Later movements would result in the further 
 intersection of this part of the district by the numerous dykes, the 
 decomposed remains of which are now to be seen ramifying through 
 the deposit. Those gradual chemical interchanges would take place 
 which resulted in the alteration of the shattered country-rock, and 
 its becoming a portion of the gangue inclosing the auriferous ma- 
 terial, which was then, or at a later time, deposited. In process of 
 time, subaerial denudation removed the sandstone, which now is only 
 to be seen on the further summits of the neighboring hills. At- 
 mospheric agency continued to carve away the less siliceous and less 
 porous portions of the country surrounding the deposit, until Mount 
 Morgan, owing to the pervious, quartzoze nature of its crest, re- 
 mained as a low hill in an undulating country. 
 
 The district of Mount Morgan has undergone extreme metamor- 
 phism, accompanied, as such metamorphism frequently is, by those 
 chemical reactions which more or less completely alter the rocks acted 
 upon. 
 
 It is probable that there was more than one period of such ac- 
 tivity, alternating with intervals of rest, during which the pressure 
 of overlying rock-masses and the cementing action of the under- 
 ground waters would slowly re-solidify the more or less shattered 
 rocks. 
 
 The deposit occupies a shattered portion of country-rock, freely 
 intersected by dykes. The largest dyke in the upper workings cuts 
 through the ore at one level, while it bounds it at another. It seems 
 in keeping with experience elsewhere, to suppose that the dykes 
 
16 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 penetrating the country formed passages along the line of contact, 
 through which and around which, by the agency of mineral solu- 
 tions, the deposition took place, sometimes on one side only, some- 
 times on both, the physical condition of the different portions deter- 
 mining, in a large measure, the extent of such deposition and re- 
 placement. It is also probable that, after the formation of the de- 
 posit, later movements caused the circulation of fresh mineral-bear- 
 ing solutions, which would lead to the enrichment of the deposit at 
 certain points, and so explain the irregular tenor of the ore. 
 
 The evidence at hand is not sufficient to enable us to determine 
 the particular rock in which the deposit was formed, and which it 
 almost entirely replaced ; but it could not have been the underlying 
 quartzite, the line of contact with which shows no .gradation into 
 the ore ; and of the other two possible rocks, the grey wacke and the 
 sandstone, the indications point to the former.* In the neighbor- 
 ing prospecting-shafts, auriferous quartzose material resembling that 
 of Mount Morgan has been found to pass into a grev wacke or grey- 
 wacke-slate, which, in turn, overlies the pyritiferous quartzite. Silicate 
 of alumina is generally present throughout the deposit. The char- 
 acter of the ore-material is such as would result from the alteration 
 of a silico-felspathic rock by the action of mineral-bearing solutions. 
 
 The numerous dykes which penetrate the deposit are the evidence 
 and the result of the dynamic agency which fissured the country- 
 rock, and in so doing prepared a ready passage for the underground 
 waters. These waters, while they may have been " thermal " (i. e., 
 of a temperature above the mean annual temperature of the district, 
 as are most underground waters), yet did not undergo precipitation 
 "in the open air." The brecciated forms which the ore sometimes 
 assumes scarcely require the explanation offered by Mr. Jack, who 
 states that " the occasionally angular condition of the sinter and 
 tumbled condition of the ironstone masses, would appear to indicate 
 that explosive discharges of gases or steam occurred at intervals 
 with sufficient violence to disturb the deposits accumulated by the 
 thermal spring." Would it not be simpler to suppose the fracturing 
 of the rock, of which there is abundant evidence, to have produced 
 irregular pieces, which would subsequently become partially rounded 
 
 * The position of the grey wacke has been shown to be between the quartzite and 
 the sandstone. The original summit of the Mount is but little below the level of 
 the base of the sandstone, while the deposit, as we have seen, overlies the quartzite. 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 17 
 
 by the solvent action of the waters percolating through their inter- 
 stices ? * 
 
 At Mount Morgan all the conditions generally considered favor- 
 able to ore-deposition were present in a marked degree. A mass of 
 country-rock, whether greywacke or sandstone, consisting of granules 
 of quartz, held together by a felspathic cement, f becomes fractured 
 by the intrusion of a series of dykes, which form a ready passage for 
 the flow of mineral solutions. Such a rock would readily lend 
 itself to alteration, and would be well fitted to receive a mineral 
 deposit. Later dynamic action produced a further metamorphism of 
 the surrounding rocks, followed or accompanied by the intersection 
 of the already shattered rocks by another series of dykes, which re- 
 opened a passage for the underground waters. In this case it is not 
 necessary to go far for the source of the gold. The large mass of 
 decomposed pyritic quartzite, though the pyrites contains but a trace 
 of the precious metal, is more than sufficient to account for the 
 wealth that has been uncovered. f 
 
 This theory explains several points which have been the source of 
 perplexity, more particularly the want of regularity in structure, 
 which was as much opposed to the geyser- as to the lode-theory. 
 The great uneven ness of the gold-contents, the frothy state of the 
 onartz, ^0 often noted, and also its hydrous condition, may be due to 
 
 * Since writing the above, I have visited and examined the equally famous Broken 
 Hill silver-deposit. AVhen I declared that the material of the Mount Morgan ore was 
 not unique, that it could be duplicated elsewhere, and that it did not, perse, require 
 any extraordinary explanation, I did not expect to see so soon an instance confirm- 
 ing my statement. The huge outcrop of the Broken Hill silver-lead lode has much 
 to remind one of the big gossan of the Queensland gold-mine. Indeed, if one 
 stands in the quarry between Brodribb's and Patterson's shafts one might easily 
 imagine oneself on floor No. 3 of Mount Morgan. The face has the same singular, 
 broken appearance, consisting of masses of ochreous earth, bands of hard, siliceous 
 ironstone, bodies of black manganic ore, together with portions of white kaolin ized 
 material (here undoubtedly altered inclusions of country-rock, and not, as at Mount 
 Morgan, decomposed felstone dykes). Both at the surface and underground, the 
 sintery stalactitic structure which is found at Mount Morgan also occurs. The hy- 
 drated iron-ores produce the same "frothy," "cavernous" material, supposed to be 
 so suggestive of a geyser and this, too, not in isolated patches only, but wide- 
 spread. I may add, that there is no doubt whatever that the Broken Hill is a " true 
 fissure "-lode, traversing the metamorphic rocks of the district (schists, garnet- 
 iferous sandstone, and quartzite, principally the first), independent of their strati- 
 fication. 
 
 f The underlying quartzite may not be the only source of the gold, for it is note- 
 worthy that the "desert sandstone" has been known to be auriferous, such gold being 
 waterworn and sedimentarv. 
 
18 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 later precipitation in cavities already formed by the solvent action of 
 the waters on the shattered portions of rock. Finally, there is no 
 need to offer any particular reason for the unusual richness of the 
 deposit, beyond the eminently favorable physical condition of the 
 original rock, the numerous channels offered to percolating waters 
 and the close proximity both of the source of the gold and of the 
 usual precipitants. 
 
 Whether this be a correct explanation of the facts, time and the 
 further development of the mine will probably decide. It may cer- 
 tainly be said, without fear of contradiction, that few mines offer 
 such an interesting field for geological speculation.* 
 
 TREATMENT OF THE ORE. 
 
 The Mount Morgan chlorination-works are among the most 
 successful and extensive now in operation. The complete success of 
 the treatment is largely due to the extremely friable character of the 
 ore, which renders it pulverization easy, while its porosity assists 
 materially in the thorough chlorination of the gold. An enthu- 
 siastic writer has spoken of the ore as " a sort of snow-drift, which 
 melts in the chlorination-vats of the company into a golden sand, 
 such as might be supposed to have been brought from the bed of the 
 river Pactolus, instead of from the top of an Australian mountain." 
 
 The capacity of the present works is 1800 tons per week. The 
 gradual alteration and enlargement of the method of treatment is 
 shown by the stamp-mill and the two chlorination-plants. The mill 
 (25 stamps) by the side of Dee creek, is a reminder of early at- 
 tempts at the extraction of the gold by ordinary amalgamation. The 
 rock which the battery was called upon to crush averaged 10 ounces 
 
 * Since I wrote the above there has come into my hands the report of the Mount 
 Morgan Gold Mining Company, Limited, presented at the last annual meeting, 
 and giving information up to July, 1890. It is accompanied with maps and sec- 
 tions, notably calculated to yield a minimum of information. It appears from the 
 report that later developments have added but little to the known extent of the 
 ore-body, the main feature of the later exploration being the driving of a cross-cut 
 south from the Freehold, at 800 feet from its mouth, proving the extension of the 
 deposit at this line and in this part of the mine as was to be expected, seeing that 
 its dip is toward the mouth of the Freehold. 
 
 Up to November 30, 1890, the mine had paid the present company 2,358,333 in 
 dividends, the total gold obtained being 756,042 ounces, worth 3,121,741. During 
 the last six months (ending November 30, 1890) 37,867 tons of stone were treated 
 and yielded 113,251 ounces of golcl, or an average of 2 ounces 19 dwts. per ton. 
 Nearly all this came from the upper workings. 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 19 
 
 per ton, but the contents of the tailings proved of much greater 
 value than the amount of amalgam obtained.. This led to a critical 
 examination of the ore at the Sydney Mint. It was found that the 
 bullion was of a fineness hitherto unknown in nature, assaying 99.7 
 per cent, occasionally 99.8, of pure gold, the rest being copper, 
 with a trace of iron. It is remarkable as being almost entirely free 
 from silver. Its value per ounce was 4 4s. 8d, pure gold being 
 worth at the London Mint 4 4s. \\ld. Dr. Liebius, of the Sid- 
 ney Mint, considered, as the result of numerous experiments, that 
 the iron present was in the form of an oxide, which coated the gold 
 and so prevented its contact with the mercury.* Parcels of the ore 
 were then sent to the Technological Museum at Melbourne, where 
 Messrs.- Newberry and Vautin subjected it to numerous tests. It 
 was found that when dehydrated by heat it became less refractory; 
 and its treatment by chlorine was suggested.f The ordinary Platt- 
 ner process, as worked in California, was found quite unsuitable, 
 owing to the extremely fine crushing which it required, and which 
 resulted in the formation of slimes, greatly hindering subsequent 
 filtration. It was then that Mecsrs. Newberry and Vautin planned 
 the method which has since, with the addition of some mechanical 
 details, been patented under their joint names. J 
 
 While the stamp-mill proved incapable of extracting a proper 
 percentage of the gold, the peculiar character of the ore is remark- 
 ably suited by the process now in use. The extremely minute state 
 of subdivision of the gold and the very friable nature of the gangue 
 caused, in wet. stamp-milling, a considerable loss in "float," carried 
 away in the readily-formed slimes; but the character of the ore indi- 
 cated that dry crushing would prove effective ; and hence the early in- 
 troduction of Krom rolls was the first great improvement made. The 
 old works, which are just above the stamp-mill, receive their supply 
 
 * My own experience witli the ores of Gilpin county, Colorado, leads me to 
 believe that this is, more frequently than is usually supposed, the obstacle to suc- 
 cessful amalgamation. 
 
 f It had been previously treated with chlorine by Limberner at Gympie. 
 
 % The mine-manager informed me that nothing of the original Newberry -Vautin 
 plant remained save a piece of old shafting. The Mount Morgan Company bought 
 the right to use the process, and hence does not pay anv royalty. While the origi- 
 nal plant has been entirely replaced, it cannot fairly be said that the method of 
 treatment has been changed, or that it is any other in its main features than that 
 known by the names of those who first adopted it. Into the question of the origi- 
 nality of the process it is not within the province of this paper to enter. It has 
 been ably discussed by the Xew York Engineering and Mining Journal. 
 
20 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 on an aerial tramway, three-fourths of a mile long, with a total fall 
 of 400 feet. It is of the Hallidie type, uncommon in the colonies, 
 but familiar to American mining engineers, and need not therefore be 
 here described. The feeding of the buckets (of which there are 
 sixty) is admirably effected by the use of a travelling supply-bucket. 
 The old works contain two rock-breakers, one revolving ore-dryer, 
 four sets of rolls, ten furnaces, fourteen barrels, twenty-six vats and 
 twenty-eight filters. The power is supplied by one 40-H. P. 
 (nominal) engine and two 30-H. P. boilers. The practice in these 
 works is identical with that in the new works about to be described. 
 
 The new works, ejected on the higher slope of the mountain, 
 about 400 feet from the summit, while somewhat similar to the 
 lower works, show improvements in arrangement, besides allow- 
 ing the necessary fall for the tailings. The ore, coming from the 
 open cuts and the Freehold tunnel by a series of inclines (some of 
 which are automatic gravity-tramways) passes through two Blake- 
 Marsden rock-breakers, and is then dried in two revolving cylin- 
 drical furnaces, self-discharging after the manner of a trommel. The 
 rotation is produced by an external cog-wheel. Thence the dried 
 material goes to Krom steel rolls, arranged in two series of three 
 each. Each set of rolls is followed by a revolving sieve, the coarse 
 stuff passing into an elevator which returns it for second crushing, 
 while the fine passes on to the second rolls and thence to the third. 
 The last pair of rolls pulverizes the ore twice before it is carried by 
 a worm-conveyor to an elevator which sends it to a chamber above 
 the furnaces. An 80-H. P. compound engine drives the rolls and a 
 20-H. P. engine the breakers and revolving dryers, while two Root 
 blowers are employed in the removal of the dust, of which there is 
 a great deal. Five Cornish boilers of 30-H. P. each supply the 
 necessary steam. 
 
 The furnace-chamber is 400 by 120 feet in size, and contains 18 
 ordinary reverberatory furnaces, each having a capacity of 1 ton. 
 The heat to which the material is here exposed is a cherry-red, such 
 as will get rid of organic matter, water of crystallization, etc., but 
 does not approach that of a thorough calcination. At the end of 3 
 hours the charge is removed and spread upon the cooling-floors. 
 When it has cooled it is trucked to the 21 iron hoppers which sup- 
 ply 21 chlorination-barrels. The charge for chlorination is 1 ton 
 of pulverized ore, 90 gallons of water, 40 to 50 pounds of sulphuric 
 acid and 35 pounds of chloride of lime. It will be seen from the 
 nature of the charge that the chlorine is generated in the barrels 
 
THE MOUNT MORGAN MINE, QUEENSLAND. 21 
 
 themselves, and attacks the gold while in a nascent state.* In order 
 to make the charges uniform, the ore is mixed so as to yield 4 to 5 
 ounces per ton.f 
 
 The chlorination-barrels have been much altered from time to 
 time. They are now made at the mine out of the native timber 
 (Eucalyptus), the staves being made of " spotted gum" and the ends 
 of "iron bark/ 7 with an inside diameter of 3 feet 6 inches. A cast- 
 iron frame was at one time pla'ced round the outside edges. The 
 barrels are tarred to render them tight and are protected inside by 
 a double lining, an innermost wooden lining protecting the lead one. 
 They revolve on horizontal bearings, the power being supplied by a 
 belt travelling around the barrel itself. Six revolutions per minute 
 is the usual speed, and the charge is removed after an interval of 
 from 1J to 2 hours. 
 
 The barrels discharge into 84 leaching-tubs. These tubs or vats 
 will hold 2J to 3 tons of pulp each, and are supplied with filter-beds 
 of sand and gravel, through which the solution passes before it is 
 conducted by lead and antimony pipes to the charcoal-filters. These 
 are 64 in number, V-shaped and packed with 2 feet of charcoal of 
 unusual fineness, the upper layers having the size of coarse blasting- 
 powder, and increasing in fineness toward the bottom. From 9 to 14 
 bushels are used in each filter. 
 
 When saturated with the precipitated gold the charcoal is removed 
 to the assay-office, where it is burned to an ash containing 75 per 
 cent, of metallic gold. The solution from the filters passes into 
 tanks of concrete, whence it is pumped back to be used again in 
 the chlorination-barrels. 
 
 The sulphuric acid used in the generation of the chlorine is manu- 
 factured upon the ground in leaden chambers, having a capacity of 
 20 tons per week. It is estimated that by the production of the 
 acid on its own premises the company saves 20,000 per annum. 
 There are also extensive work-shops, with lathes and shearing- 
 machines, together with two assay-offices, well equipped with all the 
 necessary appliances. The whole plant is run continuously, being 
 lit by electricity at night, when the mountain assumes a very beau- 
 tiful and animated appearance. 
 
 The mine and all its surroundings bear testimony to the great 
 
 * After the style of the processes patented by Mears in 1877 and De Lacy in 1864. 
 f The pleasure of producing a uniform mixture of such high grade has not been 
 possible since the time of my visit. 
 
22 
 
 THE MOUNT MORGAN MINE, QUEENSLAND. 
 
 energy displayed in its development, in keeping with the value and 
 
 size of the great ore-deposit which has made Mount Morgan famous. 
 
 The accompanying plate, made from a photograph, gives a good 
 
 idea of the surroundings of the mine. In the foreground is the 
 bridge crossing the Dee creek ; immediately above is the old stamp- 
 mill; behind it is a pile of the ore first broken; and behind that 
 

 THE MOUNT MORGAN MINE, QUEENSLAND. 23 
 
 again are the lower assay-offices. To the left are the old chlorina- 
 tion-works, while the upper chimney indicates the new works. Be- 
 yond is the Mount itself, the white spot being the iron roof of the 
 main shoot which leads from the upper workings. 
 
 NOTE BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other errors, 
 or communications for publication as " Discussion," or independent 
 papers on the same or a related subject, are earnestly invited. 
 
II- 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 THE LIMITATIONS OF THE GOLD STAMP-MILL. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Chicago Meeting, being part of the International Engineering Congress, August, 1893.) 
 
 MILLING is one of the metallurgical arts whereby the extraction 
 of the largest possible proportion of the value in an ore is effected 
 at the least possible expense. Stamp-milling* is that particular 
 process in which a heavy body of iron is caused to fall upon the ore 
 so as to disintegrate it and thereby induce a separation between what 
 is valuable and what is worthless. The latter is usually less in 
 specific gravity, and is therefore, by the further aid of water, removed 
 from the former, which is then collected by the use of mercury. 
 
 Several similes have been employed to describe this process. The 
 stamp has been likened to a hammer of which the stem is the handle 
 and the die the anvil. The ore upon which the stamp falls has been 
 compared to a nut awaiting the descent of the hammer whose blow 
 is to separate the valueless shell, the quartz, from the valuable kernel, 
 the gold. 
 
 When we begin to pursue our inquiries, however, we find that the 
 analogy is just sufficiently true to emphasize the departures from it. 
 The hammer falls, the anvil is fixed ; so with the stamps and the 
 mortar. The anvil is made of softer metal than the hammer ; so 
 also the die is often, and should be always, of steel or iron less hard 
 and more tough than that of the shoe. The movement of the 
 hammer and the drop of the stamp are both intermittent. 
 
 In regard to their intermittent action, as in many other respects, 
 stamp-mills arrange themselves under two types, which, though ap- 
 parently contradictory, have both been evolved from a common origi- 
 nal, and are united by a great variety of intermediate modifications. 
 The slow speed and the high drop of the mills of Gilpin county, 
 Colorado, appear to have very little in common with the fast speed 
 and short drop of those of the main gold belt of California; yet 
 the practice of the one was largely derived from that of the other, 
 
 * I shall confine the discussion to simple gold stamp-milling. 
 
2 LIMITATIONS OF THE GOLD STAMP-MILL. 
 
 and each has been adapted to the treatment of the ores of its par- 
 ticular region. 
 
 The first and most apparent difference is that of speed. In Colo- 
 rado the drop is regulated at 30 per minute, while in California 
 it averages from 90 to 105. The more rapid drop gives a less in- 
 termittent action, and in this respect more nearly approaches the 
 ideal machine. 
 
 The work done by the hammer is, however, dependent not only 
 on the rapidity of its blows but also upon its weight and the distance 
 through which it falls. Keeping to the two types, which we have 
 chosen as representatives of the two systems of milling, we find that 
 in Colorado the stamp weighs 550 to 600 pounds and falls a height 
 of 18 to 20 inches, while in California the stamp weighs from 750 
 to 850 pounds and drops only 4 to 6 inches. Upon multiplication 
 of these three factors weight, drop, and speed we find that the 
 theoretical work done is nearly equal and is about one horse-power. 
 
 In milling, however, the efficiency of the stamp as a crushing 
 machine is gauged by the quantity of ore which it can reduce, and 
 we find that this does not at all correspond to the theoretical equality 
 of the mills. In Colorado the stamp crushes 1 ton per twenty-four 
 hours, while in California, with an ore of similar hardness, the 
 amount is from .two and a half to three times as much. Why is this 
 difference? To explain it we must suppose the hammer to fall not 
 upon the dry and wide surface of an anvil, but upon a face of iron 
 confined within a narrow box and under water. This box corre- 
 sponds to the mortar or coffer of the stamps. It has no opening* 
 save in front, where a metallic grating or screen permits the escape 
 of only that part of the material which has been crushed sufficiently 
 small to pass through the openings. The ore upon the die is 
 under water. The depth of that water depends upon the level 
 of the bottom of the aperture occupied by the screen-frame. In 
 Colorado the depth of discharge, as measured by the distance from 
 the bottom of the screen to the top of the die, is 14 inches, but 
 in California it is 4 inches only.f Herein lies the key to the differ- 
 ence in the crushing capacity of the two mills. Though the same 
 amount of power be expended, and though the screen used be of 
 similar mesh, yet in the Colorado mill the stamp falls through 10 
 
 * The feed-hole is higher up and does not concern us here. 
 
 f In making the comparison between the two systems of milling, I have pur- 
 posely chosen extreme types. 
 
LIMITATIONS OF THE GOLD STAMP-MILL. 3 
 
 inches more of water and has to discharge the pulp at a level 10 
 inches higher than in the California mill. The greater depth of 
 discharge deadens the effectiveness of the blow of the stamp and 
 weakens the force ^of the splash. Another result is obtained. While 
 the screen does not in either case succeed in sizing the material dis- 
 charged through it, yet it will be found that, though provided with 
 similar screens, the pulp issuing from the deep mortar has a fineness 
 much greater than that discharged by the shallow one. The pulver- 
 ized ore is retained by the deep mortar long after its particles have 
 been crushed to a size permitting their passage through the screen- 
 openings, and they therefore become repulverized to a further degree 
 of fineness. 
 
 This touches upon one of the points in respect of which the stamp- 
 mi 11 is most faulty. By actual test it is found that, though using a 
 40-mesh screen, for instance, with the theoretieal supposition of 
 crushing to that particular size, yet in a Colorado ifcill fully 70 per 
 cent, of the pulp, and in a California battery about 50 per cent., will 
 pass through a 100-mesh sieve. The percentage varies with the 
 character of the ore, but these figures may be considered fairly rep- 
 resentative. Two causes are chiefly responsible for this. The most 
 important in its effects is the pause which occurs between the succes- 
 sive drops of the stamp. In a Colorado mill the interval is two 
 seconds; in California it varies from three-fifths to two thirds of 
 a second. Particles of ore, which have been pulverized to a fineness 
 which would permit of their exit through the screen, are enabled to 
 settle towards the bottom of the mortar. It would be expected that 
 the heavy metallic minerals occurring in the ore would, because of 
 their greater specific gravity, be most affected by this feature of the 
 treatment. In practice this is found to be so. The fine slimes con- 
 tain a large proportion of metallic sulphides, generally valuable on 
 account of their close association with the precious metals, while the 
 coarsest particles to be found in the tailings usually consist of quartz 
 and other minerals forming the less heavy gangue. 
 
 The want of any proper control over the regular sizing of the 
 pulp is also due to the unequal and irregular splash of the water in 
 the battery and the hap-hazanl way in which the particles of pulver- 
 ized ore strike against the screen. In the case of any single particle, 
 for instance, it is a question of hit-or-rniss whether it be thrown 
 against an opening or a blank. If it fail to pass through, it is 
 thrown back by the recession of the water and undergoes a further 
 agitation and probable pulverization. 
 
4 LIMITATIONS OF THE GOLD STAMP-MILL. 
 
 In practice this feature of the stamp-mill is recognized by both 
 the California and the Colorado rnillman. On the Pacific coast the 
 mortars are made narrow, thereby diminishing the opportunities for 
 the settling of the particles of ore, and, by increasing the force of 
 the splash, adding to the chances of its exit through the screen. In 
 late years there has also been a tendency to use wire-cloth in place 
 of punched iron, for the reason that the former, though having 
 openings of identical size, yet has more of them per square inch 
 than the latter, and, therefore, presents a greater area of discharge. 
 By giving an inclination of 10 degrees to the screen-frame, the exit 
 of the pulp is further assisted. 
 
 In Colorado, this defect of the stamp-mill has been utilized, 
 and has been made an assistant to the millman. The mortars of 
 this district are wide and roomy, the splash of the water inside the 
 battery is weak, and the pulp remains inside until pulverized to 
 a fineness mticH^gxceeding that required foi its passage through the 
 screen. There is a reason for this apparently contradictory feature 
 of the milling practice. To explain it we must glance at the ore. 
 We find it to contain an average of 15 per cent, of pyrite. The 
 gold is very fine and intimately associated with the pyrite. To 
 separate them it is necessary not only to crush to a certain degree of 
 fineness, but also to obtain conditions which will- permit the gold 
 when once separated to settle upon amalgamated plates placed in- 
 side. The deep discharge causes the pyrite to remain in the mortar- 
 box long after it has been pulverized to a size smaller than the 
 screen-openings; the long drop gives the interval of time required 
 to allow of the settling of the fine gold, while the roomy character 
 of the mortar aids the deep discharge in affording a chance for the 
 gold to get out of the way of the falling stamps and to become 
 amalgamated upon the two copper plates inserted at the back and 
 front of the mortar. In this way about two-thirds of the total yield 
 of amalgam is obtained inside the mortar. In California the 
 introduction of plates is not admissible, in rnortars having so shal- 
 low a discharge as 4 inches, because the more constant and more 
 violent agitation of the pulp prevents the settlement of the gold 
 and would cause the abrasion or "scouring" of the surface of 
 amalgamated plates. A certain varying percentage of gold is, 
 indeed, usually arrested inside, partly by the aid of mercury 
 added to the ore as it is fed into the battery, but this is of such 
 a coarseness that gravity alone would serve to keep it within the 
 mortar. 
 
LIMITATIONS OF THE GOLD STAMP-MILL. 5 
 
 We have now entered into the discussion of the effects produced 
 by the action of the stamp upon the ore. In many respects it de- 
 parts from the analogy of the hammer which cracks open a nut. 
 While being lifted the stamp also turns. This is effected by the 
 friction of the cam-surface against the under side of the tappet. In 
 a slow-drop mill the stamp makes a complete turn each time it is 
 lifted, but with an increased speed this action is more uncertain and 
 from 4 to 10 drops are required to make a whole revolution. 
 
 This feature of the stamp-mill breaks the analogy to the hammer 
 and anvil, and causes it to resemble the pestle and mortar. The 
 turning of the stamp in rising is communicated to the ore when it 
 falls and induces a grinding-action, which has important results. 
 The mere impact of the stamp upon the particles of gold has the 
 effect of hammering it, of increasing its density and of preventing 
 its amalgamation, while the turning of the shoe upon the die causes 
 the abrasion of the surface of the gold and the rubbing off of any 
 film of foreign matter, which, by preventing contact between the 
 gold and the mercury is prejudicial to amalgamation. In grinding 
 the ore the stamp, however, also tends to convert it into slime. The 
 hammer which cracks open the nut liberates the kernel without 
 smashing it, but in pursuing the simile we find that the stamp not 
 only breaks the shell, but both the kernel and the shell are further 
 crushed, and their particles become confused together. The stamp 
 which frees the gold from the quartz has to deal with a material in 
 which the valuable and the valueless constituents are so uneven in 
 size and so intermixed that the one is often crushed too much and 
 the other too little. 
 
 I have seen auriferous quartz* which very nearly approached our 
 simile of the nut. The gold occurred in seams and cavities in a 
 quartz which had a honeycombed character. With such an ore 
 there is just a certain blow which will break the brittle quartz and 
 liberate the ductile gold. Such ideal conditions are very rare. The 
 different parts of the same ore usually vary both in hardness and 
 composition. The same work done on two pieces of mill-stuff will 
 produce entirely dissimilar results. In the stamp-battery the heavy 
 sulphide minerals are pulverized to a greater fineness than the si- 
 liceous gangue. When the gold is not too closely associated with the 
 pyrite, coarse and rapid crushing will produce an adequate separa- 
 tion; but when the metal is in a finely divided condition and very 
 
 * At Clunes, Victoria, Australia. 
 
6 LIMITATIONS OF THE GOLD STAMP-MILL. 
 
 intimately mixed with the pyrite, then fine crushing is demanded 
 and can, unfortunately, only be obtained by the production of a very 
 undesirable excess of slimes. 
 
 We have glanced at the results produced by the turn of the stamp 
 upon the ore. Upon the mechanism itself the results are beneficial. 
 The revolution of the stamp equalizes the wear upon the shoes and 
 dies. It tends, also, by maintaining an even crushing-surface, to 
 prevent that decrease of efficiency which occurs when either hammer 
 or anvil has an irregular face. 
 
 Water is the vehicle used for the removal of the valueless por- 
 tions of the ore from those which are valuable. Its low specific 
 gravity as compared to both the metal and its enclosing gangue en- 
 ables us to use it as a medium for their separation. A liquid 
 having a specific gravity greater than that of water, and interme- 
 diate between that of the gold and its gangue, would be more effec- 
 tive if its use were practicable, which it is not. 
 
 In the mill, however, specific gravity is not the only factor we 
 have to consider. The water discharged from a stamp-mill often 
 transports the heavy pyrite further than the light quartz. This is 
 due to the fact, already referred to, that the pyrite remains inside 
 the mortar longer than the quartz and becomes pulverized to a 
 further degree of fineness. It, therefore, presents a larger surface 
 to the water. Again, the metallic sulphides commonly occurring in 
 gold ores have a cleavage more highly developed than that of quartz ; 
 therefore, while the latter finds its way into the water in irregular 
 and angular grains, the former will be found in thin plates and 
 flakes, which readily float upon a running stream. 
 
 Water is the fluid used, but air also plays its part. During the 
 time of its violent agitation under the falling stamp, the water en- 
 tangles a certain amount of air. Such air exists in the form of 
 small bubbles which hold the finely-pulverized ore in suspension 
 and thus become the main agent in the floating of the slimes. 
 Warmth causes the air to expand and the bubbles to become dis- 
 sipated ; therefore any rise in the temperature of the water, such, 
 even, as is caused by the impact between the stamps and the ore 
 upon the die, is favorable to a diminution in the amount of 
 slime. 
 
 When the pulp is discharged from the mortar-box it runs down 
 copper plates covering long sloping tables. The copper, whether 
 plain or silver-plated, is provided with an amalgamated surface, 
 and it is this amalgamated surface which is supposed to do the 
 
LIMITATIONS OF THE GOLD STAMP-MILL. 7 
 
 work of arresting the gold. Mercury unites with gold forming a 
 heavy amalgam; hut, in practice, it is found that a plate which is 
 covered with a good coating of gold-amalgam will serve to arrest 
 gold much more effectually than a clean surface of either amalga- 
 mated silver or copper. 
 
 The amalgamating-tahles have a slope varying with the amount 
 of water used, the heaviness of the pulp, and the rapidity of the 
 crushing. A gradient of |-inch per foot is common in Australia, 
 while in Colorado the inclination is over 2 inches per foot.* The 
 colonial mills consume 5 gallons of water per stamp per minute, 
 while those of Colorado use less than 2 gallons. Theoretically, the use 
 of the least possible quantity of water, and the spreading of the pulp 
 over the largest possible surface, will give the best separation of the 
 gold from the gangue. In practice, the varying composition of the 
 ore prevents a nice adjustment of the conditions. You may readily 
 determine an inclination which will be most effective in causing a 
 separation of the gold from the quartz, but, it may be such as to 
 cause the pyrite to settle. On the other hand, the slope may be so 
 adjusted that the pyrite is carried away ; but, such conditions may 
 then be obtained as will also permit of the escape of the gold. 
 
 The amalgamating-tables are attached to the frame-work of the 
 mill. The vibration set up by the falling stamps causes a pulsation 
 of the water flowing over the plates similar, in a way, to the action 
 of a jig. This assists the work of gravitation. The vibration has, 
 however, another effect, namely, that of crystallizing the iron of the 
 working parts of the mill, making them brittle and decreasing their 
 time of service. In this, as in other respects, the stamp-mill presents 
 contradictory features. 
 
 At the outset, we described milling as the art of treating an ore 
 so as to extract the maximum of value at the minimum of expense. 
 Let us apply the description to the two types of mill to which par- 
 ticular reference has been made. In Colorado, a stamp crushes 1 
 ton of the ore of the Gilpin county mines in 24 hours, and the cost, 
 using free water power, is 70 cents. In California, the best 
 equipped large mills crush at the rate of rather more than 2J tons 
 at a cost, also using free water power, of about 35 cents per ton. 
 The extraction in both regions will be, by amalgamation alone, about 
 70 per cent. We will omit the amount extracted by the concentration 
 of any valuable pyrite, because the percentage of such material is 
 
 * An Australian mill usually crushes 2 tons per stamp per 24 hours. 
 
8 LIMITATIONS OF THE GOLD STAMP-MILL. 
 
 very variable, and it forms a by-product, the value of which depends 
 largely upon local conditions. 
 
 The ore of the Gilpin county mines carries about 15 per cent, of 
 pyrite, and other heavy sulphides. The gangue is more feldspathic 
 than quartzose, and is the product of the alteration of the country- 
 rock granitoid gneiss and of the dikes* which penetrate it. The 
 gold is not only present in a state of very fine subdivision, but it is 
 also intimately associated with the pyrite. 
 
 On the other hand, the mill-stuff treated in Amador, Calaveras 
 and Tuolumne carries from 1 to 2 per cent, of pyrite. The gangue 
 is quartz, but the ore also contains a very large proportion of the 
 country-rock, which in this case is slate, augite schist, and diabase. 
 Of these, slate predominates. The gold is coarser than that of the 
 Colorado ore, and it is not so closely associated with the pyrite. 
 
 Let us now consider the results to be obtained by an interchange 
 of treatment, using California batteries on Colorado ore, and vice 
 versa, f The Gilpin county ore is of medium grade, say 8 dwts., or 
 $8 per ton. The local methods extract $5.60J at a cost of 70 cents. 
 A California mill would give an extraction of only $4, but would 
 crush such soft ore fully three times as fast, so that the cost would 
 be, say 25 cents, giving a net yield of $3.75 as against $4.90 obtained 
 by the methods of the district. Here, the slower mill gives the 
 best results with a particular ore, and the Colorado mill man con- 
 siders the California!! very stupid because he does not use Colorado 
 methods. Let us go to California and use the Gilpin county mill 
 upon an ore of simpler character and of lower tenor. We will con- 
 sider the treatment of an ore. containing 6 dwts., or worth $6 per 
 ton. The California mill would extract 70 per cent, at a cost of 
 35 cents, leaving a balance of $3.95 per ton. The Colorado battery 
 would extract an increased percentage, say 75 per cent., but the ore 
 being much harder than that of Gilpin county, the crushing capacity 
 would be less and the cost per ton greater than when treating Gilpin 
 county ore, say, therefore, $1.00 per ton, leaving a net yield of $3.50 
 per ton. The California mill, if crushing 100 tons of ore per day, 
 would, therefore, show a profit $45 per day greater than that of the 
 Colorado mill. As a matter of fact, there are other practical con- 
 siderations which would render inadvisable the interchange of 
 
 * The "porphyry" of the miners; really, quartz-andesite. 
 
 f In making the comparison the cost of motive power, being very variable, is 
 left out of the count. 
 
 J Amalgamation only, omitting concentration afterward, is here included. 
 
LIMITATIONS OF THE GOLD STAMP-MILL. 9 
 
 methods, among which may be mentioned the smaller size of the 
 ore-bodies of Gilpin as compared to those of California; while it must 
 also be remembered that the construction of a Colorado mill of a 
 capacity equal to that of a California plant would require twice as 
 much capital. 
 
 The comparison just made will serve as an illustration of the 
 fact that milling is a business for getting money, and not a scientific 
 pursuit directed to the obtaining of a perfect metallurgical treat- 
 ment. 
 
 The contrast between the methods in use in two mining districts 
 in the same country, illustrates the first axiom of all successful ore- 
 reduction, namely, that the treatment must be suited to the char- 
 acter of the ore. Colorado methods in California would probably 
 fail just as surely as California ways have been unsuccessful in 
 Gilpin county. This is a truism not always remembered by ma- 
 chinery firms, who do not desire to be bothered by the making of 
 new patterns. Too often, the ore is required to bend to a certain 
 treatment in a mill of a particular design, instead of the mill being 
 modified to suit the necessities of a particular ore. 
 
 The stamp-mill has presented to us many contradictory features. 
 It is seen to be compounded of good and ill. It may be simple, but 
 it is clumsy ; it may be crude, but it is effective. As a machine, it 
 has undergone an evolution common to all human inventions. It 
 was founded on the first stone implement of the prehistoric savage; 
 it became modified into the matate of the Mexican and the tilt- 
 hammer* of the Chinese ; it progressed until running water was 
 called in to aid human muscle, and in the machine of the Hun- 
 garian peasant, it reached the primitive type from which our 
 present mills were evolved. How great has been the comparatively 
 recent improvement can be seen by stepping from Hungary to Cali- 
 fornia. 
 
 In the valleys around Verospotak, in Transylvania, the larger 
 mills f consist of twelve stamps, in coffers holding four each. The 
 power is derived from an overshot water-wheel 10 feet in diameter. 
 The cam-shaft is of iron, and revolves on agate bearings, lubricated 
 with water. The lifter, or cam, is iron-shod. The stamp weighs 
 250 pounds, and has an agate head. The stem, the coffer, and all 
 
 * " A Chinese System of Gold-Milling," by Henry Louis, Trans., xx., 324. 
 
 f Modern American mills have been lately introduced, and can be seen working 
 side by side with those dating back to 100 A.D. For the particulars above given, 
 I am indebted to Mr. E. H. Liveing. 
 
10 
 
 LIMITATIONS OF THE GOLD STAMP-MILL. 
 
LIMITATIONS OF THE GOLD STAMP-MILL. 11 
 
 the rest, are made of beechwood. Each stamp drops 30 times per 
 minute, and crushes about 300 pounds of soft ore per 24 hours. 
 These machines have changed but little since the time of the Roman 
 occupation under Trajan, when this district was a part of the province 
 of Dacia.* 
 
 Let us now go to California, whose record is little more than the 
 record of a generation. Among the foothills of the Sierra Nevada 
 we find mills containing 80 stamps, weighing 750 to 850 pounds 
 each, and dropping 95 times per minute. Those of the working 
 parts which are not of iron are made of steel. At single mills, 200 
 tons of ore are crushed per day. The mill building has a height 
 of 70 feet, and the ore is never touched by manual labor from the 
 moment that it arrives at the top in the mine-cars to the time when 
 it is discharged at the bottom as waste. 
 
 In Transylvania, the individual shareholder often has his own 
 mill; in California a thousand unite to operate one, which can, in 
 24 hours, treat as much ore as the Hungarian mill crushes in 100 
 days. The little machine of the Hungarian has been tapping away 
 like a woodpecker for eighteen centuries, and yet has not produced 
 as much gold as has been contributed in the brief time of one gen- 
 eration by that completer mechanism whose muffled thunder echoes 
 among the canons of California. f 
 
 What has been done may serve as a measure of what can yet be 
 done. Perfection is as unattainable in milling as in any other branch 
 of industrial art ; otherwise progress were soon ended. We can com- 
 pare the old mill with the new, not only with a complacent satisfac- 
 tion at the advance that has been made, but with the consciousness 
 that where so much improvement was possible much room for im- 
 provement must remain. 
 
 It is not for me to attempt to foretell what place the stamp-mill 
 is destined to hold in the metallurgy of the future. Let me, however, 
 in concluding, suggest the reflection that though the appliances of 
 to-day may show a great advance upon the older more imperfect 
 type from which they were evolved, yet there is no mining district 
 that possesses a mill which cannot, in some essential, be improved upon. 
 
 * Well-preserved gold coins of the time of Trajan have been found in the mine- 
 dumps. 
 
 f The accompanying illustration of an old and a new mill has been engraved 
 from a pen-and-ink drawing, made by my friend, Mr. H. R. Pridham, after a pho- 
 tograph taken by myself during my residence in California, some years ago. In 
 the middle distance is an old ruined water-wheel, formerly the motor of a small 
 ten-stamp mill, the dismantled portions of which remain in the shed on the left. 
 In the background is a fully equipped, modern, California steam-mill. 
 
4 
 
 Subject to Revision. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.) 
 
 THE GOLD-FIELDS OF OTAGO. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Plattsburgh Meeting, June, 1892,) 
 
 THE province of Otago consists, roughly speaking, of the southern 
 half of the South Island* of New Zealand. On three sides it is 
 washed by the Pacific Ocean and on the north it abuts against West- 
 land and Canterbury. It covers an area of over 20,000 square 
 miles, and for the most part has an extremely broken surface ; the 
 narrow plains of the sea-board are bounded by the rounded foot- 
 hills which in turn are overlooked by range after range of the snowy 
 summits whose varied beauty has made the island known as the 
 Switzerland of the southern hemisphere. 
 
 The gold-fields are confined to the quartzose schists which, in a 
 broad band, 70 to 75 miles wide, cross the district extending in a 
 northwesterly direction from the shore of the western ocean into the 
 northern provinces. These quartzose schists are the characteristic 
 rocks of Otago, and to their curious structure are due the interesting 
 differences exhibited by the mining districts in the modes of occur- 
 rence of the gold. These rocks, which are almost unbroken over 
 their full extent, have been divided by the Provincial Geologist, f 
 F. W. Hutton, into two series of beds, named respectively the 
 Wauaka and Kakanui formations. The only reason given for this 
 division is the desire " to divide such an enormous thickness of rocks 
 in order that the map might display somewhat of the geological 
 structure of the district.''^ As Hutton and others have pointed out 
 there is in fact no dividing line. The changes noticeable in the 
 ascending series of schists are very gradual, and are due to the 
 slowly decreasing effects of metarnorphism. Hutton estimates the 
 thickness of the Wanaka series at as much as 50,000 feet, and the 
 
 * New Zealand is variously spoken of as consisting of the North, Middle and 
 South islands or of the North, South and Stewart's Island. The last is of insignifi- 
 cant size and importance. Otago is in the southern of the two chief islands. 
 
 | That is, the geologist of the province of Otago. It is the term used in the gov- 
 ernment publications. 
 
 J Page 33 of Geology of Otago, 1875. 
 
2 THE GOLD-FIELDS OF OTAGO. 
 
 Kakanui at 52,800, or twenty miles for the two. The information 
 obtainable is not sufficient for trustworthy estimates, but it is certain 
 that these rocks have an enormous thickness over a very large area. 
 
 The question of their age is surrounded with much difficulty. 
 The geologists of New Zealand are not agreed as to either nomen- 
 clature or chronological position ; and the maps of the several 
 authorities show most unfortunate divergencies of opinion. For our 
 immediate purpose it may suffice to say that the quartzose schists of 
 Otago overlie the syenitic gneiss and granite, which Hector and 
 Hutton agree in regarding as pre-Silurian ;* while they underlie a 
 are overlain by those of the Matai, the geological position of which 
 was for a long time sharply debated, but has been determined by 
 fossils as Carboniferous. Such is the evidence upon which the 
 quartzose schists have been labelled Silurian. 
 
 The rocks themselves have been variously described as phyllite, 
 clay-slate, mica-schist, etc. Hornblende-schist and quartzite are 
 also known to occur. The mineral constituents are subject to fre- 
 quent variation. The name " phyllite " is often used, but since the 
 argillaceous character of the mica-schist has been seldom more than 
 guessed at, this usage may be taken as a mere faon de parler. 
 Neither of the above names describes distinctively the rock which 
 forms the prevailing type, and I would suggest "quartzose mica- 
 schist," or, for brevity, " quartzose schist " as being more descriptive. 
 
 The most striking and at times a very remarkable feature of 
 the schists of Otago is the extraordinary development of quartz. In 
 many localities (for instance, in the twelve miles between Lawrence 
 and Waipori, where the road-cuttings afford numerous sections) the 
 quartz forms half the bulk of the rock. It is interbedded among 
 the folia of the schist, often in very regular and continuous lines. 
 The seams of the quartz will, over a wide area, have an average 
 thickness of from half an inch to an inch, increasing often to bands 
 5 or 6 inches wide.J Fig. 1 illustrates an outcrop of such quartz- 
 banded rock. 
 
 It is noteworthy that over the greater part of the gold-fields the 
 
 * Sir James Hector calls the granite pre-Silurian, and F. W. Hutton has called 
 the formation by the name of Manipori, and considers it Lanrentian or Cambrian, 
 series of rocks called Devonian and Carboniferous,f which in turn 
 
 f Je Anau series (Devonian) of Hector or the Kaikora formation (Carboni- 
 ferous) of Hutton. 
 
 t Above La Grave, Hautes Alpes, I have seen sections in the Lias which strongly 
 reminded me of this feature of the Otago schists. 
 
THE GOLD-FIELDS OF OTAGO. 3 
 
 beds preserve a very flat dip over very wide areas and are rarely, 
 and only locally, much tilted. 
 
 That the quartz is formed along lines of bedding, and not cleav- 
 age-planes, is amply proved by the observation of the changes in 
 the character, color and composition of the rock, which take place 
 at right angles to the lines of foliation, whose low angle of inclina- 
 tion is also confirmatory, since cleavage is usually characterized by a 
 high angle. 
 
 The quartz is most probably of secondary origin, and due to the 
 exudation of silica from an extremely siliceous silt and segregation 
 along the lines of lamination during the period of metamorphism. 
 
 To those acquainted with the mineral deposits of the Western 
 United States, Europe or Australia, the almost entire absence of 
 eruptive rocks over such a wide auriferous area will appear extra- 
 ordinary. It will also largely explain the scarcity of lode- forma- 
 tions, the comparative want of definition which belongs to most of 
 the veins, and the small extent of the ore-bodies, notwithstanding 
 the fact that large portions of the country-rock are undoubtedly in 
 themselves gold-bearing. To the latter fact is due the enormous 
 quantity of alluvium, the yield from which is much greater in im- 
 portance than that of the quartz-veins of the province. 
 
 The history of the first discovery of gold in Otago has been re- 
 lated by one of the pioneers Vincent Pyke. It may be considered 
 as dating from the 4th of June, 1861, the day upon which a Dune- 
 din newspaper published a letter from Gabriel Reed announcing the 
 finding of gold at Tuapeka.* 
 
 Before that date, a native of Bombay, Edward Peters, or " Black 
 Peter," as he was more generally known, had been getting gold in 
 what was afterwards famous as Gabriel's Gully, the locality which 
 saw the first great " rush " of 1861. In the following year the 
 known auriferous area was extended far into the mountains of the 
 interior, and on August 16, 1862, Hartley and Reilly a native-born 
 American and a Yankee Irishman astonished Dunedin by deposit- 
 ing at the treasury a bag containing 87 pounds of gold. They had 
 been quietly working on the beaches of the Clutha river near the 
 Dunstan gorge, and the announcement of their find caused the then 
 small population of Otago to make a hasty stampede into the in- 
 
 * The first discovery of gold in New Zealand is said to have been made at Driv- 
 ing Creek, Coromandel, in 1852. The Coromandel district has, however, been over- 
 shadowed by its neighbor the Thames, which has had a most brilliant though irregu- 
 lar record. Neither of them has been such a regular producer as Otago. 
 
4 THE GOLD-FIELDS OF OTAGO. 
 
 terior. From this time immigration from the Australian colonies 
 set in, and gold-fields were proclaimed* in rapid succession. 
 
 Between September and December, 1862, 70,000 ounces were sent 
 by escort to Dunedin from Dunstan. 
 
 The working of the gold-deposits was rendered easy by the fact 
 that, unlike the wash of the Victorian fields, that of Tuapeka, the 
 first Otago gold-field, and those of the province generally, contained 
 but little clay, and did not necessitate the " puddling " which, at old 
 Bendigo for instance, was the treatment required by the stiff, hard- 
 ened " cement" of the Australian alluvium. 
 
 Nuggets do not figure much in the history of the Otago gold-fields. 
 According to Vincent Pyke the largest was one of 27 ounces, re- 
 ported to have been found at Waipori in 1863. Nuggets were com- 
 paratively rare, and the few found were very small, and in no way 
 comparable to those which in the early " fifties " made Ballarat and 
 Dunolly famous. 
 
 The production of Otago is shown in the accompanying statement : 
 
 The Gold-Production of New Zealand. 
 
 ' 
 
 Auckland. 
 
 West Coast. 
 
 Otago. 
 
 Total." 
 
 Year. 
 
 Oz. 
 
 Value. 
 
 Oz. 
 
 Value. 
 
 Oz. 
 
 Value. 
 
 Oz. 
 
 Value. 
 
 1889 
 1890 
 
 28,655 
 31,745 
 
 113,191 
 125,760 
 
 101 ,696 
 89,096 
 
 406,451 
 356,368 
 
 64,419 
 63,410 
 
 256,430 
 255,926 
 
 203,211 
 193,193 
 
 808,549 
 773,438 
 
 Highest 
 yield, 
 
 886,820* 
 
 1,188,708 
 
 552,572* 
 
 2,140,946 
 
 614,387* 
 
 2,380,750 
 
 735,376* 
 
 2,894,517 
 
 Total 
 since '57, 
 
 1,639,357 6,122,473 
 1 
 
 5,093,249 
 
 20,226,540 
 
 4,783,96818,886,928 
 
 11,818,221 
 
 46,425,629 
 
 a. Including minor districts. 
 
 b. This was in 1871, at the time of the Thames rush. 
 
 c. Due to the Hokitika discoveries. 
 
 d. When the Gabriel's Guliy Diggings were at their best. 
 
 e. In 1871. 
 
 The mining industry of Otago at the present time offers a variety 
 of interesting features. The methods by which the precious metal 
 is won are very diverse, including dredging and hydraulic elevating 
 in addition to the ordinary forms of alluvial and deep mining. In 
 lode- or vein-mining the "quartz-reefing " of the colonies Otago 
 is considerably behind its neighbors of the Australian continent, but 
 
 * When the auriferous character of a district has been proved the colonial gov- 
 ernment " proclaims " it a gold-field. 
 
6 THE GOLD-FIELDS OF OTAGO. 
 
 in alluvial mining it is first, and in dredging it is the pioneer. 
 We will first consider the 
 
 LODES. 
 
 One of the oldest and best of the gold-fields is that of Waipori, 
 discovered very soon after Gabriel's Gully, which is only 10 miles 
 distant. The most important lode is that of the "O. P. Q." or 
 Otago Pioneer Quartz mine, which was discovered in March, 1862, 
 by six Victorians, all Shetland men, who named it the Shetland 
 reef. The country-rock is a very fine silver-green mica-schist, with 
 an enormous proportion of interfoliated quartz. The strike of the 
 lode is N. 30 W., and the dips eastward 50 to 55, becoming more 
 flat in the deeper workings. The enclosing rock dips 15 to 20 
 S. S. E., and the lode, therefore, cuts across it in both strike and dip. 
 It traverses a low range of hills, across whose brow the croppings 
 can readily be followed. The dimensions of the vein are subject to 
 frequent change ; indeed, it would be more correct to consider the 
 quartz as occupying a line of fractured country in which the distinc- 
 tion between the quartz of the surrounding schists and that of the 
 lode itself is often obliterated. The work done has proved the ex- 
 istence of large irregular blocks of gold-bearing quartz of lenticular 
 form, and over-lapping each other.* Sometimes two or more of 
 these blocks of ore may be parallel to each other and separated by 
 soft. country, which near the quartz passes gradually into a black 
 clay or fluccan.f In this manner rich short shoots of stonej have 
 been discovered ; but the greater part of the gold is contained in the 
 country-rock included by the lode, that is, the vein-filling, which is 
 threaded by numerous small cross- veins, dying out insensibly among 
 the quartz seams of the surrounding schists. It would be mislead- 
 ing to speak here of foot- and hanging- walls in the usual sense. 
 As a New Zealand miner would put it, "each run of stone makes 
 its own wall." The bodies of quartz preserve, indeed, a certain line, 
 which is that of the strike of the fissure or line of fissuring in which 
 they have been formed ; but it would be wrong to speak of defined 
 walls as limiting the gold-bearing portion. The eastern boundary 
 the hanging-wall of the lode preserves a fairly straight course, but 
 
 * This recalls similar formations elsewhere. At the Frederick the Great mine, 
 Sebastian, Victoria, the ore-shoots were of a strikingly similar character. 
 
 f Selvage. The New Zealander calls it " pug." 
 
 J The colonial miner generally uses the word " stone " instead of " quartz " 
 or "ore." 
 

 THE GOLD-FIELDS OF OTAGO. 7 
 
 there are only suggestions of a foot-wall, a series of parallel or nearly 
 parallel division-planes, separating the quartz of the enclosed from 
 that of the enclosing schists. 
 
 On the Waipori side of the ridge, the lode traverses a portion a 
 bar of country-rock more siliceous and harder than usual ; and it 
 is to be noted that within this passage the quartz is barren of gold, 
 and contains a smaller amount of iron pyrites than in the softer por- 
 tions of the hill. In washing the lode-matter, one notices a heavy 
 white mineral, which lingers with the pyrites and gold after the rest 
 of the gangue has been washed away. This is the somewhat rare 
 mineral scheelite or tungstate of lime,* which in this district occurs 
 scattered through the schists, though rarely in workable quantities. 
 In addition, the country-rock contains occasional thin veins of cin- 
 nabar, irregular in behavior and too small to have economical im- 
 portance. The presence of the mercury mineral is not observed in 
 working the lodes, but it forms a marked feature of the alluvium with 
 the gold of which it is mixed. 
 
 About a third of a mile westward is the parallel lode of the Can- 
 ton mine, where the true character of the formation is more readily 
 discernible. Fig. 2 illustrates the appearance of the end of the 
 southeast drift. A A is the " reef," a vein of quartz which is sup- 
 posed to lie immediately upon the " foot-wall. " Along B B the 
 country is soft, and the included quartz folia are much twisted. 
 C C is one of the " false hanging-walls." The whole width is gold- 
 bearing, though A A acts as a guide in following the auriferous 
 channel. It is not possible to say where the "lode" ends or where 
 it begins. It is a channel of country-rock which is auriferous within 
 ill-defined limits, and in which the vein A A acts as an indicator. 
 Along A A and C C, it has undergone faulting ; along B B, distor- 
 tion only. It is an extreme case of what a colonial calls a " mul- 
 locky reef," a lode full of mullock or waste rock a type of ore- 
 deposit more common than is supposed, though the usual forms are 
 less distinct than in this case.f We shall see somewhat of the same 
 structure in the other districts of the province. 
 
 * Specific gravity, 5.9 to 6.1 ; composition, CaO 4 W. At Glenorchy, at the 
 head of Lake Wakatipa, I examined a mine which had been worked for this 
 mineral. 
 
 f In this particular case, those working the mine had little comprehension of the 
 formation. I was informed that there were several " false hanging-walls," but that 
 there was only one foot-wall, which was said to be of a different rock, much harder 
 than the hanging. On examination, I found the rock of the so-called foot-wall to 
 be similar to that of the rest of the country enclosed by the lode ; and on crushing 
 
THE GOLD-FIELDS OF OTAGO. 
 
 The chief lode-raining or "reefing" district of Otago, which lies 
 north of Lake Wakatipu, presents a great contrast to that which 
 surrounds Waipori. The latter consists of peculiarity monotonous 
 rounded hills, covered with a peaty soil on which the tussock grass 
 of the ridges and the flax .in the gullies are the only vegetation- 
 The rounded outlines of these foot-hills have been ascribed to glacial 
 erosion in the same way that much else in Otago is put down to this 
 little understood agency. However that may be, we have here the 
 basal wrecks, the stumps, as it were, of what were once mountains, 
 perhaps as rugged as those further inland. Denudation has de- 
 graded them to uninteresting hillocks, and the peaty soil which covers 
 them now serves to protect them from rapid erosion. Farther inland, 
 the foot-hills become more striking to the eye by reason of the very 
 curious weathering which has left numerous isolated rocks standing 
 above the surrounding level like an army in skirmishing order. See 
 Fig. 3. 
 
 These have been sometimes supposed to be the rocky freight 
 brought down by glaciers ; but they are in situ, and the explanation 
 of their occurrence is difficult. The peculiar weathering which 
 originated the names Rock and Pillar. Raggedy Ridge, Rough Ridge, 
 etc., given to some of the hills of Otago, is not of uniform occur- 
 rence, being less marked as the coast is approached. I have noticed 
 that the schist of which these isolated rocks are composed is usually 
 more siliceous than that of the surrounding country, and I would 
 suggest that it is the irregular segregation of siliceous material which 
 has induced this very unequal weathering. 
 
 At Barewood, where I examined a large number, I found that, 
 almost without exception, each of these pillars, usually about 10 or 
 15 feet high, contains a cup-shaped hollow of varying size. This 
 is on the side towards which dip the prevailing quartzose schists 
 of which they are composed ; and it is doubtless due to the forma- 
 tion first of a small hollow by the action of rain-water, followed by 
 the removal, by wind and rain, of some of the softened mica-schist. 
 In the concavity so formed, rain-water would lie, and, by the aid of 
 frost, would shatter the interfoliated quartz. Along the banks of 
 the mountain torrents this action has progressed more rapidly, and 
 the. rocks exhibit a honey-combed appearance. 
 
 it and testing it with the "dish " or pan, it was found to be richer than the portion 
 then being mined. It was scarcely necessary after that to advise the miners to put 
 a cross-cut into the " foot-wall." 
 
10 THE GOLD-FIELDS OF OTAGO. 
 
 To return to the northern mining districts. The region about 
 Lake Wakatipu, in which they occur, is crossed by the snowy ranges 
 of the Southern Alps, 10,000 to 12,000 feet in height, the highest 
 summit, Mt. Cook, having the altitude of 12,350 feet. By the 
 sculpture of frost and snow, the structure of the mountains has been 
 laid bare ; and though they are carved from the same rocky mate- 
 rial as the lower country,* the rugged, bleak, precipitous ranges, with 
 their coronets of snow, are in strong contrast to the rounded contours 
 of the brown-paper-like hillocks around Waipori. 
 
 In this district, Arrowtown, Macetown, and Skippers are three of 
 the best-known mining centers. At Macetown, near the head of 
 the Arrowf river, are the Tipperary, Premier, and Sunrise mines. 
 
 The Premier, at the foot of Advance Peak, offers several points of 
 interest. A series of three nearly parallel lodes is met by a counter- 
 lode, and at the junctions ore-shoots occur. The two cross-sections, 
 Figs. 4 and 5, indicate the relative positions of the members of this 
 lode-system. The dip of the No. 2 or main lode brings it across 
 the others, which are thereby deflected, but not cut. At the meet- 
 ing-point ore-bodies occur ; but so far only one of these junctions 
 the lower junction of the No. 2 and the No. 3 has been thoroughly 
 developed. The ore-shoot there found has a flat inclination (about 
 45) along which it was followed by a series of irregular workings. 
 There is always a clear division-plane, or " wall/' between the two 
 lodes when after the junction they are seen to go forward in com- 
 pany. 
 
 The cross-cut from the lower adit to the No. 2 lode indicates the 
 relation of the lodes to the quartzose schist of the country. See Fig. 
 9. The folia of quartz (dipping about 20) which are flat in the 
 country become more nearly vertical as the lode B is approached. 
 They become broken by fractures A A, which can be followed until 
 they lose themselves in the vertical lamination of the schist encas- 
 ing the quartz of the " reef." Fig. 10 shows the appearance of the 
 No. 1 reef as seen in the back of the level, the sketch being in plan 
 or horizontal section. The width of the lode proper is 15 to 18 
 inches, strike N.W., dip, 75 to 80. On the foot-wall side there 
 are a couple of inches of " pug " or selvage, on the opposite wall 
 
 * Quartzose schist. This refers only to the mountains in the vicinity of the 
 raining districts cited. The main ranges westward are formed in part of granitic 
 rocks. 
 
 f So-called because not straight lucus a non lucendo. In riding from Arrowtown 
 to Macetown the track crosses the winding river twenty-five times in 10 miles. 
 
- 
 
 z 
 
 s 
 
 cc. 
 
 UJ 
 
 i 
 
 LJ 
 
 cr 
 
 Q- 
 
 A/fV^jMVV'.V 
 
 \rJl)V\i-M\ 
 
 Li * . ^S^^ / 
 
12 THE GOLD-FIELDS OF OTAGO. 
 
 there is none, the lode passing gently into the country-rock. The 
 foliated quartzose schist included between the limits of the lode is 
 very beautifully contorted. The schist, both that included within 
 the lode and that encasing it, is very quartzose, the seams being 
 about J to J inch thick. The lode as such contains irregular pieces 
 of quartz ; but, as a whole, it carries very little more quartz than the 
 enclosing schist. 
 
 Fig. 11 is a sketch of the No. 2 lode, taken in the stopes 75 feet 
 above the main adit. The " reef" consists of B B, sugary quartz 
 about 4 to 5 inches wide. Fig. 1 2 is also close by. R R is crushed 
 quartz; D is broken-up material in which quartz predominates; C 
 is foliated quartzose schist. The so-called "foot- wall," A A, con- 
 sists of a division-plane marked by black clay. There are also 
 similar partings between R and D, and C and D. Quartz is found 
 behind both the so-called walls. B B, the auriferous portion of the 
 lode, steps from one side to the other, advancing southeast. The 
 so-called walls, while they last, are clean and marked by a graphitic 
 surface, accompanied with clay; but they continue their course 
 through the country-rock after the quartz has left tnem, to be formed 
 again along other nearly parallel similar divisions. 
 
 At the Sunrise mine, on Advance Peak (Fig. 13), a similar type 
 of lode occurs. The lode is divided by a number of distinct part- 
 ings accompanied with unctuous clay. Tne country-rock near the 
 lode is conformable to the "walls" of the lode. C is the " reef," 
 consisting of crushed mottled quartz, carrying pyrites and stibnite ; 
 A is clayey, soft and broken ; B is very much contorted quartzose 
 schist ; D is of similar material ; E is more regular, and F is the 
 country-rock itself. The total width is 4 feet 8 inches. It is ex- 
 pected that BCD will form the width of the lode as the level is 
 advanced. 
 
 These two mines illustrate a type of lode, the structure of which 
 is rendered evident by the peculiar rock in which it occurs. I leave 
 the further consideration of this interesting formation until I shall 
 have passed in review the lodes at Skippers. 
 
 Macetown is divided from Skippers by a high ridge (6000 feet) 
 overlooking the Shotover river, which flows between. Ascending 
 this ridge at Advance Peak, one obtains a fine view of the configur- 
 ation of the country. The natural beauty of mountain land is de- 
 stroyed by the severe weathering, which has prevented the growth 
 of timber, save in sheltered corners. The ranges extend in their 
 nakedness like the skeleton of some huge saurian. Their structure 
 
THE GOLD-FIELDS OP OTAGO. 13 
 
 can be readily discovered ; the dip-slopes are debris-strew and in- 
 cline at a low angle, while the opposite faces are precipitous and 
 rocky in the extreme, cut up by well-marked systems of jointage. 
 On the summits of the ridges the soft schists show the evidence of 
 the easy and rapid degradation which they undergo when exposed to 
 the snow and frost of these higher altitudes. Landslips on a large 
 scale are common and temporarily dam or permanently divert the 
 mountain streams, causing heavy floods, such as the historic one of 
 1878, which altogether changed the distribution of the auriferous 
 beaches of the Shotover river. 
 
 The reefs at Skippers are perhaps the best known of the Otago 
 lodes, on account of the Phoenix mine, locally celebrated as the first 
 to utilize the electric transmission of power for the working of its 
 stamp-mill. Like the other lodes we have considered, those of 
 Skippers consist of a system of several gold-bearing quartz-veins 
 traversing a more or less defined ore-channel. The lodes are three 
 in number, forming a lode-channel which dips north and has a 
 variable strike of about N. 80 W. They are known as the North, 
 Middle and South lodes respectfully, and frhe Middle is the richest 
 and strongest vein, and the main ore-producer. They are approxi- 
 mately parallel ; but, even when close together, never lose their in- 
 dividuality. There is a good hanging- wall to the north of the series 
 and a good foot to the south ; but the intermediate walls of the dif- 
 ferent members of the series are irregular and indistinct. The 
 shoots of gold-bearing stone have two marked features. The first 
 is, that they make in step-like gradation from one lode to the other. 
 Shoots on any two lodes are never opposite each other, whether in 
 vertical or horizontal section. It is almost the converse of "ore 
 against ore." See Figs. 6 and 7. The other noteworthy character- 
 istic of this system of gold-veins is that they are particularly poor 
 when their strike is south of west, while they are almost invariably 
 found to become gold-bearing whenever a turn takes place to the 
 north of west. As the result of these two features, it is found in the 
 working of the- mine that one lode is rarely rich for any great dis- 
 tance ; that when it is gold-bearing in a given portion, the portions 
 of the other two lodes which are immediately opposite will be poor; 
 that when it becomes barren the gold is to be looked for at a point 
 opposite in one of the two other lodes; and of the two, in that one 
 whose course at that point is north of west. 
 
 The mine is worked by adits. At the level of the No. 3 adit the 
 south lode is intersected at 96 feet from day-light, the Middle at 24 
 feet beyond, and the North at 60 feet further still. 
 
THE GOLD-FIELDS OF OTAGO. . 15 
 
 The shoots of gold-bearing stone are from 50 to 200 feet in length ; 
 forthe most part they pitch strongly to the west, but are not con- 
 tinuous in- depth. However, as one ore-shoot comes to an end, 
 another is discovered below ; and the deeper workings expose ore- 
 bodies which do not extend to the surface. A cross-course cuts the 
 lodes at a strong angle, faulting the Middle lode, which on the east 
 side was called the " Promised Land " lode until it was recognized 
 as a faulted portion of the Middle lode. Immediately east of the 
 cross-course the lode was very rich. Fig. 14 illustrates the Main 
 lode as seen in the 150-foot level stopes. A is disordered soft 
 country lying against the hanging. B is f< payable stone " quartz 
 and included country merging into each other ; the quartz is dark 
 and mottled, carrying a small percentage of arsenical pyrites. The 
 gold is coarse and often visible. C is country-rock included within 
 the lode and arranged parallel tp the foot- wall which it follows. 
 The whole width is 8 feet. A is 2| feet. C is 3 feet. 
 
 The reefs of Skippers, Macetown and Waipori have certain fea- 
 tures in common, due to the identity of the country-rock which they 
 traverse, and probably also to their contemporaneous origin. In 
 each case the structure is that of a group of lodes rather than of one 
 single vein. The series of two or more approximately parallel reefs 
 occupying fractures formed along a more or less defined belt repre- 
 sents the relief given to the compression of the rocks by a large 
 fault-fissure such as that of the Comstock vein. The contortion ob- 
 servable in the country included within the limits of the ore-chan- 
 nel, and the frequent partings which are also lines of faulting, lead 
 one to the belief that more than one movement of varying intensity 
 took place. The fine-grained, closely foliated quartzose schists 
 yielded in part, by the formation of folds, to the compression to 
 which they were subjected, while the strain was further taken up by 
 the production of a set of co-ordinated fissures. Along these lines, 
 later movements crushed the intervening enclosed country, and thus 
 by preparing a channel for the percolation of mineral solutions, cre- 
 ated in a varying degree the locus of gold-deposit. 
 
 The outside members of any such system of lodes usually have 
 walls which respectively form the boundaries of the ore-channel. 
 Such walls are usually accompanied by a varying thickness of black 
 clay or gouge. Generally speaking, however, the distinction be- 
 tween "country" and "reef" is arbitrary. The quartz of the reef, 
 the quartzose schist of the included country, and the somewhat less 
 quartzose schist of the enclosing country shade off imperceptibly. 
 
16 . THE GOLD-FIELDS OF OTAGO. 
 
 Sometimes there is no line of division between the reef and the en- 
 closing rock; at other times there is a line of parting, which is Sig- 
 nified by the name of "foot-wall " or " hanging-wall." 
 
 There is reason to believe that the quartz of the lodes sometimes 
 occupies fractures formed along the axes of anticlinal folds ; but, as 
 a rule, tbe type of structure is that shown in miniature in Fig. 8 
 from a sketch made by me from a cutting on the Shotover main 
 road. The sketch covers a width of 5 feet. Instead of forming a 
 narrow clean-cut crack or fissure, the soft schist, by reason of its in- 
 terfoliated quartz which renders it of varying hardness, is traversed 
 by a belt of dislocated country bounded by two parallell fractures. 
 The interfoliated quartz enables one to see clearly that there has 
 been a movement resulting in the disarrangement of the parallelism 
 of the quartz lamina?. In this case the fracture (from a to 6) has a 
 width of only 7 inches; but the structure is similar in origin and 
 kind to that which we have seen forming the larger lodes of the 
 mines. The part between the two lines of fracture forms the begin- 
 nings of the " mullocky reef" of the colonial miner, that is, a lode 
 carrying a large proportion of included country-rock. Percolating 
 waters deposit their quartz first a'long the lines of parting, and we 
 get a twin system of veins; and if the action be continued further, 
 the intervening filling is also silicified. It may seem a long step, 
 from a lode like the Premier, the larger part of which is gold-bear- 
 ing material which is crushed, included country-rock, to a massive 
 vein of clean auriferous quartz ; yet in truth the difference is not of 
 origin of structure, but of degree only, being due to the variable 
 extent to which quartz has replaced the country-rock. 
 
 Before leaving this part of the subject, I would venture the sug- 
 gestion that lode-mining in Otago has a future scarcely to be inferred 
 from the scanty results hitherto obtained. Examination of the lodes 
 shows that they are found in channels but little divided from the 
 main mass of the country- rock, and that the quartzose schists are 
 auriferous in themselves, outside the boundaries of such lode-chan- 
 nels. The formation strongly points to the probability that there 
 will be found certain belts of country-rock sufficiently auriferous to 
 become mines. At present, gold-milling in Otago is in a very crude 
 condition ; but with the improvements made in the treatment of 
 gold-quartz ores and the consequent decrease of the cost of handling 
 them, there will come a day when large "low-grade gold-proposi- 
 tions" will give lode-mining in this part of New Zealand an im- 
 portance now unsuspected. 
 
THE GOLD-FJELDS OF OTAGO. 
 
 17 
 
 
 
 d> 
 
 
18 THE GOLD-FIELDS OF OTAGO. 
 
 ALLUVIUM. 
 
 The alluvial deposits of Otago are far more developed than its 
 quartz lodes. The extent of the gold-bearing alluvium lying among 
 the highlands of the province is imperfectly known ; but so far as 
 it has been explored, all facts point to the conclusion that it is enor- 
 mous. The gravel-deposits present many features in marked dis- 
 tinction to those of California and Australia, between which two 
 there is, on the contrary, a striking resemblance.* The gold-drifts 
 of California are chiefly in the Pliocene, and so are those of Victoria ; 
 but the alluvial gravel of Otago belongs to the Lower Miocene and 
 to other periods. The beds of lava which, in both California and 
 Victoria, are found capping the alluvium are conspicuously absent 
 in Otago, where, moreover, the deeper lying drifts are not so impor- 
 tant a source of gold as the more shallow deposits of the rivers. 
 
 The gold is usually in fine flakes, and only the uppermost reaches 
 of the rivers show the nuggetty character of other districts. Nug- 
 gets of any size are very rare, and the largest on record weighed, as 
 already observed, only 27 ounces, while California can boast of one 
 found in Calaveras county, f weighing 195 pounds, and worth $43,- 
 534, and Victoria has furnished the Welcome Stranger/' weighing 
 248 ounces, and wortfi 9534 or $47,670. f 
 
 The great extent of the Otago alluvium is due to a combination 
 of causes, among which the character of the prevailing rock and the 
 low snow-line are the most important. The limit of perpetual snow 
 is at about 7000 feet above the sea. The prevailing rock is the 
 quartzose schist, which is very rapidly eroded, and the debris from 
 
 * Yet, notwithstanding this well-known fact, it is curious to note how very little 
 Victorian and Californian geologists and engineers seem to know or care to know 
 of each other's work. Investigations are twice made, and ground is twice covered, 
 owing to this want of intercommunication. 
 
 f According to a statement made by John Hays Hammond in the Ninth Annual 
 Report of the State Mineralogist of California. Dr. Raymond gives, in the Report 
 of the U. S. Commission of Mines and Mining for 1869 (published 1870), p. 452, a 
 list of famous Australian and Californian nuggets, including two from California, 
 weighing 106 and 160 pounds respectively, and half a dozen from Australia, rang- 
 ing from 112 pounds upwards, the heaviest two being the Ballarat nugget of 1853, 
 weighing 168 pounds, and the famous " Sarah Sands," weighing 223 pounds, 4 
 ounces. 
 
 J The " Welcome Stranger" was found at Moliagul, near Dunolly, February 5, 
 1869. Though several bits had been previously broken off by the discoverers, it 
 yielded, on melting, 2268 ounces, 10 pennyweights, 14 grains. The original 
 nugget contained 2280 ounces of melted, or 2248 ounces of pure gold, being valued 
 at the Bank of England at 9534. 
 
THE GOLD-FIELDS OF OTAGO. 19 
 
 which is washed down into the great natural tail-races of the Clutha, 
 Shotover and Kawarau rivers. These rivers are subjected, by the 
 rapid thawing of large masses of snow, to frequent flooding and the 
 diversion of their channels by the detritus brought down. The soft 
 character of the bed-rock soon makes a temporary channel a perma- 
 nent one ; and so it happens that, even at the higher altitudes, ter- 
 races of gravel and old river-beds are frequent and form prolific 
 sources of the precious metal. 
 
 The most extensive alluvial deposits are found along the course 
 of the Clutha, formerly called the Molyneux. This river is to the 
 miners of Otago, in some respects, what the Nile* is to the Egyptian 
 fellaheen, though it is the great artery, not of fertile^ lowlands, but 
 of auriferous highlands. The anxious cultivator beside the banks of 
 the historic northern river does not watch the rise and fall of its 
 waters with more anxiety than does the energetic New Zealander the 
 rapid current of the southern stream, whose quick rise or gradual 
 fall may mean on the one hand the cessation of work and the flood- 
 ing of claims, or, on the other, the steady ingathering of a golden 
 harvest. 
 
 The Clutha affords some interesting lessons in physical geography- 
 With its seven-knot current, it sweeps down through 'the easily 
 eroded schistose rocks in which it has cut for itself a natural sluice- 
 box, the riffles of which are the rocky bars, while its head is at the 
 feet of the glaciers, and its lower end empties into the Pacific. 
 Where the river now flows there was once a chain of fresh- water 
 lakes, cut out by the glaciers which have now retired further inland. 
 These lakes received the tribute of the upper highlands in the form 
 of the gold-bearing gravel which was deposited on their bottom. In 
 later times the Clutha worked it way from lake to lake, and finally, 
 having worn down its channel deeply through the schists, it emptied 
 the lakes, cut through the deposits which had been formed in them, 
 and now flows unfettered to the sea. 
 
 The main features of the country through which it passes are bare 
 mountain ridges of high elevation, diversified by narrow valleys of 
 pastoral land. Narrow rocky gorges separate wide flats of evidently 
 lacustrine origin. That part of the river from the Island Block to 
 Alexandra is typical. At the former point there occurs an old chan- 
 nel, separated from the new by a ledge of rocks ; and above the 
 
 * It has been stated that the Clutha carried a volume of water equal to that of 
 the Nile. The estimation of the Clutha was correct, but the Nile was probably in- 
 correctly gauged. 
 
oz 
 
 t 
 
 CO CO 
 
 -I Q 
 CO 
 
THE GOLD-FIELDS OF OTAGO. 21 
 
 junction of the two channels there is a narrow gorge, which is suc- 
 ceeded by the wide flats of Ettrick, through the eastern side of which 
 the river has cut its way. Then follows another rocky canon, to be 
 succeeded by the small lake-basin in which the Hercules Company 
 is finding " pay gravel." Continuing north, below Roxburgh bridge, 
 comes a short rocky cutting which opens out into Coal Creek flat, 
 from which it is 6 miles to Coal Creek gorge, and then 25 miles of 
 narrow ravines to the Alexandra terraces which mark the successive 
 levels of an old lake. 
 
 Tne Island Block is now the scene of important mining operations. 
 There the present river (see Fig. 15) flows on the eastern side of a 
 rocky ridge which forms an island between the river of to-day and 
 that of a former period. The old river-channel, about J mile wide 
 and 4J miles long, is marked by a valley of the most valuable pas- 
 toral land in Otago. Its upper end opens out towards the banks of 
 the present river, but forms a narrow gorge at its lower end where 
 (at the point marked by a cross in Fig. 15) the Island Block Com- 
 pany is working. The configuration of the valley is further shown 
 in Fig. 16, in which sketch C is the island, A the point where the old 
 and new channels meet, which is overlooked in the distance by B, the 
 Old Man Range, D indicates the lower slopes of the Spylaw Hills. 
 
 The Island Block Company commenced work at the immediate out- 
 let of the old channel ; but it was found that there was here a narrow 
 deep rocky gorge, the overhanging sides and rapidly shelving bottom 
 of which had prevented the deposition of the gold. Going inland, 
 the channel widened, and the bottom became less steep. Soon 
 however the gravel was cut off by a bar of rock. It was then 
 decided to test the channel at a point nearer the center of the valley ; 
 but on bottoming, hard schist was encountered at 60 feet, and no pay 
 gravel was found. The next step was to cut right across the sup- 
 posed line of channel. This met with success. On the south side, 
 after having raised 50,000 cubic feet of barren material the elevator 
 bottomed upon " a lead " 3 to 4 feet thick, and carrying rich gravel. 
 Mining operations have thus shown that the old channel is more 
 irregular than would at first sight be supposed. Fig. 19 exhibits 
 the arrangement of the large boulders which lie upon the bed rock. 
 The gold is found, in the heavy silt which has been caught among 
 the interstices of the boulders, the arrangement of which forms a 
 natural riffle, resembling the " pavement-riffle 7 ' of the miner. 
 
 At Waipori there is a similar deposit in the old bed of the Lam- 
 merlaw Creek. It is shown in plan and section in Figs. 17 and 18. 
 
22 THE GOLD-FIELDS OF OTA GO. 
 
 The deposit has a depth of 54 feet and a width varying from 25 to 
 30 feet. The sides are very irregular, and there are several distinct 
 layers of gravel, making " false bottoms." The origin of this old 
 channel is easily explained. The country rock is here traversed by a 
 lode, the croppings of which have been found in the bed-rock. They 
 contain gold, and have a strike which brings them in line with the 
 " Ofcago Pioneer Quartz" lode worked on the opposite hill. (This 
 is somewhat after the manner of the deep leads of Ballarat, where, 
 when the alluvial deposits had been worked out, the mines had a 
 second lease of life through the development of the quartz-veins, the 
 croppings of which had been found in the bed-rock of the alluvium.) 
 Here the lode-channel, consisting of rock softer than the average, 
 offered an easy passage for the Lammerlaw, on its way to join the 
 Waipori river. Having become filled up during a time of flood, 
 the channel was diverted and formed the Lammerlaw Creek of 
 to-day. 
 
 Near Waipori is the celebrated Blue Spur. This is perhaps the 
 best known and most interesting alluvial deposit in New Zealand. 
 It is situated near the head of Gabriel's Gully, about two miles east 
 of the town of Lawrence. The name is derived from the color of 
 the alluvium which was first discovered in the gully at the foot of 
 the spur into which it was afterwards traced. The blue, or, more 
 accurately greenish-blue, tint is probably due to the silicate of the 
 protoxide of iron. The deposit consists of a mass of cement and 
 conglomerate, occupying a cup-shaped hollow in a ridge or spur 
 which divides two nearly parallel gullies. Figs. 20, 21 and 22 illus- 
 trate it. Fig. 20 is a cross-section. The con tour-line of the ridge as 
 here shown is obtained from an old photograph taken in 1865. The 
 working of the deposit has entirely altered the lines. The longer 
 axis is nearly at right angles to the present trend of the Blue Spur 
 ridge, the depression which the deposit fills having been cut out of 
 the Wanaka schists r the characteristic rocks of Otago. Fig. 22 gives 
 the longitudinal section. The gully on either side is partially filled 
 with tailings. 
 
 The plan, Fig. 21,, shows the deposit to have a roughly oval shape, 
 the longer axis having a strike N. 60 W., and a length of about 
 S^chains, the shorter or N.E.-S-.W. axis is 22 chains in length. 
 
 For the sake of brevity, the two longer sides of the deposit, facing 
 respectively N.E. and S.W., will be spoken of as the " Lawrence " 
 and the " further side." On ascending the ridge on the further side, 
 about 400 feet above the present level of Gabriel's Gully, the country 
 
-;.-.x 
 
 I^S^i!:!?^ 2 
 W^9K^^ % s 
 
 silliill^! 
 
 -Sl^- t:f M-^;|ii g 
 3ll^|i:$8, 1 ! 
 
 I 3 
 
 rv If A'o'- ' ' >^ -^ > 
 
 - ; y : ::.-.*~ V* Q vy/i?-- ??^t^;^5 
 
 m^^^m* 
 *^M 
 
 l'.:-^' VrfJ 
 
 .**"o'. " "?.* ^ -""LM- " ' 'V N 
 
 ^^KL;'K^ 
 
 i^:V^ J ^W*?M-i- 
 
 : . . .^ : :-'5>:-. -. .'/i:: y.v^:? 
 
 ; . . o -Ci/ 
 
 ?.:: ^^ 
 
 ^ 
 
24 THE GOLD-FIELDS OF OTAGO. 
 
 presents the appearance roughly indicated in Fig. 21 . The accumula- 
 tion of tailings will in part explain the increased width of the gullies 
 at a point opposite the deposit; but there is no doubt that this is 
 also due in a large measure to the erosion of the conglomerate which 
 formerly extended across. In both instances, the gullies narrow 
 rapidly above their intersection with the larger axis of the deposit, 
 and at a short distance become merely rocky ravines. It is also 
 noteworthy that there are marked lateral gullies which correspond 
 to the line of the deposit. 
 
 The gold first discovered in Otago, the discovery of which inaugu- 
 rated the rush to the New Zealand gold-fields, was derived from this 
 mass of wash. Neither Gabriel's nor Munro's gully proved rich 
 above their intersection with the deposit, while both were particu- 
 larly rich at and immediately below that intersection. 
 
 The mass of the cemented conglomerate has been variously esti- 
 mated at from 8 to 10 million cubic yards, but the present manager ; * 
 whose opinion is of the most value, puts it at from 11 to 12 millions. 
 The area covered is 45 acres. 
 
 A nearer view of the deposit presents the following features. On 
 the Lawrence side, the rock forming the rim of the cup-shaped 
 hollow presents a very uneven surface, and the folia of the schist 
 are much distorted and fractured. The pebbles of the conglomerate 
 are imbeded in the soft crushed country, there being no distinct 
 boundary or line of demarcation between the deposit and the sur- 
 rounding country-rock. There are longitudinal furrows in the schist, 
 parallel to the strike of the country and the longer axis of the deposit. 
 These furrows are not regular either in shape or direction. Looking 
 down from the ridge on this side, the enormous masses of wash 
 present, by reason of their unequal erosion, the appearance of a 
 miniature cordillera. Reddish layers of oxidized material form 
 marked lines through the general faint blue tinge of the cement, and 
 indicate the dip of the deposit, which is seen to be at a low angle 
 toward Gabriel's Gully, or southeastward. 
 
 Descending among the masses of conglomerate, one can observe 
 the structure of the material. Fractures cut through the included 
 fragments of the more fissile schist, but they do not pass through the 
 harder pebbles. These last are of varying size up to boulders 2 feet 
 in diameter. The wash shows a large proportion of schist-frag- 
 ments, held together by a light greenish-blue fine-grained cement. 
 
 * Mr. Howard Jackson, to whose courtesy the writer is much indebted. 
 
THE GOLD-FIELDS OF OTAGO. 25 
 
 Of the remaining portions of the material, large jasperoid boulders 
 are most prominent. 
 
 Going to the further side of the deposit, it is seen at once that the 
 rim-rock has an altogether different appearance from that noted on 
 the Lawrence side. The bounding wall is perfectly straight and 
 even, with a dip of 25 30' to the southwest. It shows incrustations 
 of alum. The schist of the country, which dips with the face of the 
 rim-rock, shows no signs of having been crushed or dislocated. When 
 first uncovered, the face of this wall is said to have been (and its 
 present appearance suggests it) wonderfully straight and smooth. 
 Exposure to the weather has induced the slow shaling off of its sur- 
 face, which is now littered with the thin sherd-like fragments broken 
 off by frost and rain. Originally the rim-rock was covered with a 
 thin layer of clay which protected it ; but this clay first hardened 
 and then cracked, to be subsequently removed by the rain ; and the 
 underlying country-rock is being rapidly eroded. Fig. 24 gives a 
 view of its present appearance. C D is the face of the rim-rock ; 
 E E are the fragments which have scaled off its surface. Along A 
 B a section has been taken, which is indicated on a larger scale in 
 Fig. 25. In this, F is the quartzose schist of the country ; E is a 
 chocolate brown indurated clay covering the rim-rock itself; D con- 
 sists of a J-inch layer of hard cement ; C is a 2J inch layer of soft 
 brown mud ; B is 2J feet of reddish small gravel ; A is the main 
 body of cement and wash. 
 
 Fig. 26 shows the arrangement of the material in a block of the 
 conglomerate. A is a layer of large pieces of the quartzose schist, 
 but sWghtly rounded ; B contains smaller brown schistose fragments; 
 C is schist rock, containing but little quartz; D is a band of bluish 
 cement; E is a highly quartzose schist bed; F contains quartz peb- 
 bles, not rounded ; G is mixed material, quartz fragments and schist 
 irregularly distributed through a cement matrix. 
 
 Coming toward Gabriel's Gully, a pink layer containing lignite is 
 seen. Near the gully, mining operations have partially uncovered 
 the bed-rock which here presents the features shown in Fig. 27.* 
 This is a section taken along a line N. 36 W., making an angle 
 of 14 with the longer axis of the deposit. At the present time the 
 edge of the rim-rock is laid bare, but the bed-rock of the gutter 
 itself is under water. It is seen that the gutter comes abruptlv 
 
 * This a rough copy of a drawing made by Mr. Howard Jackson, who was good 
 enough to allow me to make use of it. 
 
26 THE GOLD-FIELDS OF OTAGO. 
 
 against a ridge over 60 feet high ; from the foot of this it rises gently 
 towards Munro's Gully, but soon meets with another interruption in 
 the form of a wall of rock over 20 feet high,* beyond which it 
 slopes away again before taking its regular rise. Numerous irregu- 
 lar crevices, found in the bed-rock of the gutter, generally contained 
 a great deal of gold. Above this, the cement was very variable in 
 its gold-contents, which were usually arranged along certain red 
 bands. Some of the material was absolutely non-auriferous ; while 
 other portions would form a pudding-stone of golden wash, the gold 
 of which, as distinguished from the fine flakey character which it 
 usually had, was of the size of beans. 
 
 While the rim-rock rising from the gutter on the northeast side 
 was, as we have seen, smooth and regular, that of the Lawrence side 
 was rendered remarkable by " crab holes," as they were called by 
 the miners. These were irregular corrugations, not parallel or 
 straight, but narrowing and opening out at intervals. Fig. 23 is a 
 sketch; roughly representing some of these in section. These cavi- 
 ties were as much as 15 feet deep; they were covered with a casing 
 of cement as regular as plaster ; and the material which filled them 
 was a different-looking cement from that of the main body, the line 
 of division between the two being so marked as to be of assistance in 
 blasting. 
 
 The northeast wall continues underneath the Lawrence rim-rock. 
 In working along the smooth face of the northeast rim, a party of 
 miners followed it and were working their way underneath the south- 
 western " reef" f before they discovered their mistake by hearing the 
 blasting of those above them. 
 
 THE GENESIS OF THE BLUE SPUR DEPOSIT. 
 
 The above concludes the general description of a deposit the origin 
 of which is a subject of much interest. To recapitulate its main 
 features ; it consists of a mass of cement and conglomerate, lying in 
 a depression formed in the quartzose mica-schists of the Wanaka 
 series and transverse to the present water-shed of the district. The 
 country has a dip of 15 to 20 southwest, the inclination increasing 
 near this deposit. The rock on the N.E. side conforms in dip to 
 
 * This is outside the limits covered by the section given in Fig. 27 and is there- 
 fore not shown. 
 
 f The Australian and New Zealander calls the rock rising from the bed-rock of 
 the gutter the "reef." It must not be confounded with the same word, which is 
 used as a synonym of lode, ledge or vein. 
 
28 THE GOLD-FIELDS OF OTAGO. 
 
 the bound! ng-wall of the deposit on that side. On the Lawrence 
 side, there is no conformity ; the schist is disordered ; and the boun- 
 dary between the conglomerate and the country-rock is almost ob- 
 literated. On the N.E. side the bounding-wall, when first uncov- 
 ered, had a smooth, polished surface. On the Lawrence side corru- 
 gations and irregular holes were common in the rim-rock. The 
 N.E. wall continues underneath the face of the opposite side. The 
 gutter itself is in places very irregular ; it has one particular break 
 of 20 feet in height; it is separated from Gabriel's Gully by a rocky 
 ridge, and has a general rise towards Mtinro's Gully. 
 
 The deposit has a roughly- bedded struciure, indicating a gentle 
 dip S.E.-ward or towards Gabriel's Gully. The wash at the N.W. 
 or Munro's Gully end is the coarsest. Along its shorter axis, the 
 dip is scarcely noticeable, save near the edges. It is more flat on the 
 Lawrence side. 
 
 Beds of lignite occur, confined to an upper horizon of the deposit. 
 The dip of the gutter would bring the conglomerate above the pres- 
 ent surface as we go northwest. It is therefore not surprising that 
 no traces of it are found in that direction, beyond Munro's Gully ; 
 for erosion has removed it. Going south-eastward, however, it has 
 been uncovered and worked in the next parallel gully, Weather- 
 stone's. It was found again in Waitahuna Gully. Along the same 
 line, other smaller patches have been found at intervals, and finally 
 at Kaitangata, according to Sir James Hector, it underlies the coal. 
 
 The Blue Lead in Sierra and Nevada counties, California, an old 
 river of Miocene age, was to the Yuba and its tributaries what the 
 Blue Spur was to the Tuapeka. In both cases, the bulk of the gold 
 found in the river-gravel came from an old deposit, the course of 
 which lay at right angles to that of the present drainage-system. 
 
 With regard to the age of the Blue Spur deposit, it was obviously 
 formed at a period preceding that of the erosion which produced the 
 gullies the direction of which it crosses. These gullies are the 
 source of streams which feed the Clutha, whose course also lies across 
 the line of the Blue Spur Lead. The Clutha received the drainage 
 of glaciers belonging to the Pliocene period. The Blue Spur is 
 therefore older yet. This is confirmed by its occurrence under the 
 coal-measures of the Oamaru formation which is of Eocene or Cre- 
 taceo-Eocene age. It is thus perhaps the oldest gold alluvium which 
 is worked, of which there is record. 
 
 Its origin is more difficult to determine. The glaciers were in 
 Eocene times, as they are to-day, the great natural sculptors of the 
 
THE GOLD-FIELDS OF OTAGO. 29 
 
 face of Otago. All investigation into the surface geology of this 
 portion of Xew Zealand points to this agency as having cut out the 
 lake-basins which form so prominent a feature of the country. It is 
 glacial action which is generally mentioned as explaining the origin 
 of the Blue Spur. That it is no ordinary ancient river-deposit is 
 proved by the contour of the bed-rock ; for the conglomerate lies in 
 a pot-hole rather than in a regular channel. While the general 
 slope is gently southeastward, the lower end at Gabriel's Gully is 
 found to be bounded by a rocky ridge fully 75 feet in height; and 
 midway between the two gullies another rapid rise of 20 feet is en- 
 countered. Such a configuration is best explained by considering it 
 as a pot-hole or hollow scooped out by ice-action. Though there 
 are no stria? or markings produced by glacier movements now to be 
 seen, yet this is in no way remarkable ; for the bed-rock is of too 
 soft a character to have preserved any such evidence. The presence 
 of the large jasperoid boulders is confirmatory. They do not belong 
 to the locality, since no similar rock is found nearer than the Blue 
 Mountains or Tapanui, 25 miles northwestward. They were car- 
 ried down by the ice. The character of a large portion of the ma- 
 terial forming the deposit similarly indicates that it was not brought 
 down in or by a stream of water, but as the rocky freight of a 
 glacier. A large part of the wash consists of angular fragments of 
 quartz, as well as of pieces of the quartzose schist-rock, which are 
 not rounded. The agency which eroded the depression in which the 
 auriferous material lies was assisted by the structure of the rock at 
 this particular point. I have no doubt that the N.E. bounding- wall 
 of the deposit forms the line of a fault, and that the reason of the 
 formation of the rocky basin at this particular spot is to be found in 
 the fact that the schist had been crushed by the movements accom- 
 panying faulting. Of this the X.E. wall, its smooth face, and its 
 continuation under the opposite rim-rock, together with the crushed 
 condition of the S.W. country are ample evidence. The line of 
 fault is not parallel to the course of the lead ; the two meet between 
 Munro's and Gabriel's Gully; and so explain the enlargement at 
 that point of the receptacle of the ore-deposit. 
 
 This explains the natural selection of this particular place as the 
 locus of the deposit. To proceed further, the glacier in its slow 
 downward progress to the sea is temporarily arrested by the softer 
 rock which it here encounters much in the same way as a runner is 
 retarded in crossing a ploughed field. This arrest allowed the ac- 
 cumulation of a terminal moraine, which, protecting the rock on 
 
30 THE GOLD-FIELDS OF OTAGO. 
 
 which it lay, assisted the tendency of the ice to erode the softer 
 schist; where the terminal moraine at one time lay, we now find the 
 rocky bar shown in Fig. 2. A hollow was scooped out. This was 
 in early Eocene days. A little later, that subsidence took place 
 which preceded the deposition of the Oamaru series. This caused 
 the retirement of the glacier, or more accurately, the melting away 
 of its lower portion. The rocky basin which had been scooped out 
 by the ice now became a fresh-water lake, with its upper end still 
 guarded by the glacier. The ice which broke away from the foot of 
 the glacier bore with it the large boulders of jasperoid which had 
 been brought down from Tapanui. This and other material was 
 borne across the lake, to fall eventually upon its bottom as the ice- 
 floes melted. In the meantime, up above, the glacier continued to 
 plough through the soft quartzose schists and sent down a golden 
 tribute, derived from the lode-formations which it cut through. 
 The fine flakes of gold were accompanied with micaceous mud and 
 angular bits of quartz, all to be deposited in the capacious hollow of 
 the lake. Thus the rocky basin became gradually filled up with 
 confused layers of big jasperoid boulders, quartz-gravel and bluish 
 mud, the gold sifting its way to the lower portions. The subsidence 
 continuing, and with it the slow retirement of the glacier, and the 
 lake being nearly full of detritus, it became a morass. Vegetation 
 took root and flourished for a brief period. A time of flood due to 
 excessive thaw brought down a volume of water bearing the sand 
 and gravel which covered the vegetation. Being thus protected 
 from the air, the reeds of the morass became the lignite of to-day. 
 
 A river linking a series of small lakes, of which the Blue Spur 
 was one, now flowed along the course of the present alluvial lead. 
 Additional material was deposited in some places, while material was 
 removed in others. In the middle of the Eocene period, the eleva- 
 tion of the land culminated and changed the drainage-system of the 
 district. In Miocene times, the Clutha and its tributaries began 
 to flow across the line of the Blue Spur lead. That erosion then 
 commenced which, in the cutting out of Munro's, Gabriel's and 
 Weatherstone's gullies, left the gravel-deposit as a part of a dividing 
 ridge. 
 
 Reference has been made by Hutton to the fact that certain of the 
 Eocene beds contained gold in order to explain its occurrence in the 
 Blue Spur deposit. This is not needed. The examination of the 
 material composing the conglomerate shows that the larger part is 
 derived from the degradation of the primary schists. The grinding 
 
THE GOLD-FIELDS OF OTAGO. 31 
 
 by the ice of these soft rocks formed the mud which is now 
 "cement." It was from the quartzose folia that was derived the 
 coarse gravel, and, finally, it was the gold which elsewhere to-day is 
 found in the lodes and even in the rocks of the Wanaka series, which 
 made the Blue Spur not only a geological study but also a very 
 valuable gold-mine. 
 
 CONCLUSION. 
 
 The consideration of the gold-deposits of Otago, whether in 
 lodes or alluvium, is intimately connected with the study of the 
 quartzose schists which are the characteristic country-rock of the 
 one and the bed-rock of the other. In many respects these rocks 
 are remarkable. Their extent and unbroken continuity have been 
 referred to; allusion has also been made to the many interesting 
 physiographical studies which they offer; and it now remains to 
 briefly refer again to their auriferous character. 
 
 That the bulk of the gold of the extensive alluvium of Otago 
 came from the degradation of the known lodes, I do not believe. 
 The mere proportion of the known extent of the one to that of the 
 other may be an insufficient basis for such a conviction, for in this 
 country, as in other comparatively new regions, the mineral de- 
 posits are only in an infancy of development ; yet this fact has some 
 weight. The chief evidence comes, however, from the known rela- 
 tions of the lodes to the country-rock, and from the character of the 
 alluvial gold itself. 
 
 It is not necessary to recapitulate the observations made on the 
 lodes ; how they are for the most part ore-channels, the auriferous 
 filling of which shades off into the surrounding country, as regards 
 both gold-contents and structure. The gold of the alluvium has 
 not that shotty character familiar to the digger of Australia or Cali- 
 fornia. An exception must be made of the small placer-deposits of 
 some of the mountain streams, the nuggety gold of which is easily 
 traceable to its source in the neighboring quartz-veins. Such gold 
 is, however, quite exceptional, and altogether of a character different 
 from that of the great fluviatile and lacustrine deposits of the Clutha 
 and Shotover, the wealth of which is contained in the very fine 
 flaky gold, which is like bran and notable for its uniformity of size 
 and wide distribution. It has a character making it easy of recog- 
 nition among samples coming from other districts. It is also re- 
 markable that quartz stones showing gold are of very rare occur- 
 rence at the Blue Spur or in the gravel-deposits of the Clutha and 
 
32 THE GOLD-FIELDS OF OTAGO. 
 
 Shotover. The gold came, I believe, as did the gravel through 
 which it is distributed and the cement in which it is often imbedded, 
 not from the few comparatively insignificant quartz-lodes, but from 
 the great mass of the quartzose schists. The quartz folia which 
 form the characteristic feature of the schists of Otago are known in 
 places to carry gold far 'outside the limits of any of the particular 
 lode-channels which also traverse them. One could, with perfect 
 reason, regard the whole belt of quartzose schists as one large bed- 
 vein, in which the lodes now worked are merely small cross-veins, 
 a large gold-vein, through which for ages the glaciers have ploughed 
 an easy way, cutting furrows from which the quartz and schist have 
 been swept by wind and rain into the swift waters of the Clutha and 
 Shotover, to be laid down by them in the form of the great banks 
 and terraces of gold-bearing alluvium, which to-day are the chief 
 depositories of the mineral wealth of Otago. 
 
 NOTE BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other errors, 
 or communications for publication as " Discussion," or independent 
 papers on the same or a related subject, are earnestly invited. 
 
Subject to Revision. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OP MINING ENGINEERS.] 
 
 ALLUVIAL MINING IN OTAGO. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 (Lake Champlain, Plattsburgh, Meeting, June, 1892.) 
 
 Ix a previous contribution some description was given of the oc- 
 currence of the auriferous alluvium, extensive deposits of which lie 
 among the highlands of the province of Otago, New Zealand. The 
 present paper will describe some of the methods by which that allu- 
 vium is exploited. 
 
 The alluvial mining of New Zealand is not yet hindered by 
 "debris legislation." The mines are for the most part situated in a 
 country of little agricultural value, and large rivers with rapid cur- 
 rents act as tailings conveyors. In time, however, steps will have 
 to be taken to restrict the discharge into the Clutha of the tailings 
 which are slowly raising the river-bottom. 
 
 The methods of California have been followed in Otago with such 
 alterations as peculiar local conditions require. The distinctive 
 feature of the alluvial mining of Otago is the prominence given to 
 the hydraulic elevator. The all-important factor in this form of 
 mining is the control of an abundant water-supply at a suitable 
 height above the level where it is to be utilized; and in this respect 
 the gold-fields of the south island of New Zealand are most favora- 
 bly situated, the low level of the snow-line insuring a splendid sup- 
 ply throughout the year, and under a pressure which, in practice, is 
 only limited by the strength of the plant and the expense incurred in 
 its installation. This is in marked contrast with the gold-fields of 
 the Australian continent, which have, on the other hand, a magnifi- 
 cent supply of the best mining-timber. 
 
 Next to the hydraulic elevator in importance comes the dredge, 
 the use of which in Otago, under several forms, is rapidly extend- 
 ing in the exploitation of the river-bottoms and sea-beaches. 
 
 THE HYDRAULIC ELEVATOR. 
 
 This machine, which is destined to have an ever-widening field of 
 usefulness, consists essentially of an inclined pipe, at the bottom of 
 which a jet of water under heavy pressure is allowed to play, and 
 
ALLUVIAL MINING IN OTAGO. 
 
ALLUVIAL MINING IN OTAGO. 3 
 
 by its action propel through the pipe the gravel and water which 
 enter at its lower opening. The action of the jet at the foot of the 
 elevator is not limited to the direct force of the water liberated under 
 a heavy pressure, but is also in a large measure aided by the strong 
 suction induced by the vacuum created by the upward rush of the 
 water. This suction is also of importance in that it draws the gravel 
 through the opening and thereby does the feeding. Originally the 
 pipe of the elevator called the uptake or discharge-pipe was sepa- 
 rate from the jet or nozzle which was directed up it; but in the 
 newer forms of the machine the two are combined into one compact 
 casting. Not only has this modification made the elevator a more 
 complete machine, but by diminishing the unnecessary distance be- 
 tween the jet and the opening which admits the gravel, it has allowed 
 a greater advantage to be derived from the suction induced by the 
 rapid passage of the water. 
 
 By reference to Figs 1 to 5 the following description will be under- 
 stood. The bottom of the elevator has a bracket, called the " foot," 
 which is placed upon the bed-rock upon which lies the gravel which 
 it is intended to raise. The water and gravel enter at the " hopper " 
 or intake C, being drawn in by the suction caused by a powerful jet 
 of water which passes through the "jet" or " nozzle" B and im- 
 pinging upon the entering gravel and water sweeps them up the ele- 
 vator or " uptake " pipe D. At the upper end of this pipe the gravel 
 is deflected by the " striking-plate " S (Fig. 1) and proceeds down 
 the series of sluice-boxes arranged at a gentle incline. These sluice- 
 boxes are provided along their bottom with riffles and other con- 
 trivances to arrest the gold carried in the gravel, from which it 
 separates by the action of gravity. 
 
 Gravel and water hurled with such velocity as belongs to a jet 
 under a head of several hundred feet, must produce great wear and 
 tear upon any surface against which they impinge. The greatest 
 amount of friction takes place at the lower part of the uptake-pipe, 
 called the " throat " (E). This is narrowed so as to prevent the 
 scattering of the jet and the consequent decrease of its effectiveness. 
 A strong removable casting called the " liner," is here inserted. It 
 increases gently in diameter from its lower end upward. See Figs. 
 2 and 5. A liner three inches thick lasts about six weeks. 
 
 Passing up the elevator pipe, the gravel meets the " striking- 
 plate." This is a heavy piece of iron 2 feet square and 3 inches 
 thick. It should last from two to three months; but a defective 
 casting will be broken in a few hours. The force of the ejected 
 
ALLUVIAL MINING IN OTAGO. 
 
 gravel is not all expended upon the striking-plate, hence the head 
 sluice-box, the sides of which are usually raised to 2J feet, is lined 
 with iron plate (No. 12 boiler-plate), to protect the wood-work. 
 
 Fig. 5. 
 
 ,8 holei 
 
 J 
 
 D 
 
 E 
 
 
 
 , 6 holes for & bolts 
 
 Outer nozzle bored 
 Out and Inside noz- 
 zle turned to fit 
 
 THE ATMOSPHERIC NOZZLE 
 
 FITTED TO THE 
 
 HYDRAULIC ELEVATOR 
 
 When properly handled, the elevator is a most effective machine, 
 raising a cubic yard or 1-J tons of gravel per minute, together with 
 
ALLUVIAL MINING IN OTAGO. 5 
 
 a large volume of water. Thus it not only lifts the gravel but also 
 acts as a pump in getting rid of the water used in breaking down 
 the face of the wash. Its usefulness in the latter capacity is highly 
 important to those engaged in the working of claims the bedrock 
 of which may be below the drainage-level. It is this feature of the 
 machine which has rendered it of special service in the alluvial 
 mines bordering upon the rivers of Otago. 
 
 The first introduction of the hydraulic elevator* in Otago was 
 made by Cranston and Perry in 1882. John Perry did a good 
 deal of experimental work about that time, and in 1884 inaugurated 
 the first successful working at the Blue Spur in Gabriel's Gully.f 
 
 The Blue Spur. This ranks among the first of the alluvial mines 
 of New Zealand. The English company (the Blue Spur and Gabriel's 
 Gully Consolidated Mining Company Limited), which was formed 
 by the amalgamation of a large number of miners' claims, is at 
 present only working the tailings, of which there is an enormous 
 body lying in Gabriel's Gully. These tailings have a maximum 
 thickness in the center of the gully of 72 feet, while the face now 
 being worked is 59 feet high. They are estimated to cover an area 
 of 120 to 130 acres, of which the company owns 23 acres. 
 
 The original deposit (described in my former paper) was worked 
 in the first instance by numerous small parties of miners by means 
 of ground-sluicing supplemented with the crushing of the larger 
 lumps of cement in small stamp-mills, the big, hard boulders being 
 picked out previously by hand and thrown to one side. I could not 
 find that any gold was got in the large quartz pebbles; it was al- 
 most entirely confined to the blue cement forming the bulk of the 
 material. This cement was very hard, and the gold now obtained 
 is due in large measure to the disintegration of the solid lumps left 
 in the tailings. 
 
 The accompanying sketch, Fig. 6, will indicate the appearance of 
 the workings and the method of exploitation. To the left is seen 
 the nozzle or giant, the diameter of the brasses being 2J inches, 
 supplied by a 10-inch pipe carrying water under a head of 400 feet. 
 The water-race, fed from the Waipori river, is 31 miles long. The 
 
 * Also called " tailings elevator " at Ballarat, "ejector " and " lift" in Otago. 
 
 f Since writing the above, my attention has been drawn to a description by Dr. 
 R. W. Raymond (Trans., viii., 254), of a dredge invented by Gen. Roy Stone, in 
 which a jet under heavy pressure is used to break the material under water (as a 
 similar nozzle does on land), and the material so excavated is sent to the surface by 
 the action of another, larger jet, working inside a pipe. 
 
ALLUVIAL MINING IN OTAGO. 
 
 
ALLUVIAL MINING IN OTAGO. 7 
 
 nozzle is represented as playing upon a face of tailings about 59 feet 
 high, separated from the bed-rock by 6 to 8 feet of black silt, in 
 which are the layers of wash which were worked in the early days, 
 as is evidenced by the timbers of old shafts and drifts which are 
 occasionally displaced by the water. Immediately above the lower 
 bed of alluvium was the site of the old township which sprung up 
 at the time of the rush of 1861, now, however, completely buried 
 under 50 to 60 feet of tailings. Its former position is proved by the 
 miscellaneous assortment of articles* which the sluice-boxes collect. 
 These occur imbedded in the silt together with a large quantity of 
 lead in the form of shot, reminders of that eccentric fusilading which 
 often characterizes a mining camp in its early stages. The gold 
 obtained from this ground is usually coated with quicksilver. 
 
 The nozzle is about 50 yards from the first elevator, which is 
 shown next to the right. The wash is driven by the water from the 
 nozzle into the opening or hopper of the elevator, the man in charge 
 removing the larger boulders which tend to choke it. The dimen- 
 sions are: hopper, 14; jet, 2; throat, 6J, and uptake pipe 15 inches 
 in diameter. The water which does the work comes under a pres- 
 sure of 430 feet through a 10-inch pipe. The material is lifted 15J 
 feet, and, impinging upon the striking-plate, passes down the sluice- 
 boxes which are 3 feet wide and in lengths of 12 feet, with a grade 
 of 9 inches in 12 feet. Two hundred and forty feet further to the 
 right is the second elevator, which raises the gravel again, this time 
 through a vertical height of 56 feet through a pipe 65 J feet long, 
 inclined at an angle of 58 45'. The second elevator has /iimen- 
 sions similar to those of the first, and delivers the material into 
 sluice-boxes having a grade of 9J inches in 12 feet, whence it is 
 finally deposited on the tail ings- heaps, most of the water finding its 
 way into the main drain along the true bottom of the gully. One 
 of the shafts connecting with the drain is shown to the middle right 
 of the sketch. In the immediate foreground is the pressure-pipe of 
 the first elevator. The smaller pipe shown near the elevator itself 
 is only brought into use in cleaning up the sluice-boxes. The face 
 of the bank of tailings is kept up by an arrangement of fascines, 
 which are roughly indicated to the right, above the shaft. 
 
 All the gold saved is obtained from the run of sluice-boxes be- 
 
 * Coins, gold and silver, rings, copper rivets, nails, etc. Among other curiosi- 
 ties, the manager showed me several nuggets which had been obtained in cleaning 
 up. These, judging by the character of the gold, were obtained in some other dis- 
 trict, very probably Ballarat, and lost here. 
 
ALLUVIAL MINING IN OTA GO. 
 
ALLUVIAL MINING IN OTAGO. 9 
 
 tween the two elevators. These boxes, as already stated, have a 
 general grade of 9 inches in 12 feet, but the last two or three have 12 
 to 14 inches. The bottoms are covered with cocoanut matting, 
 over which are placed riffles of angle-iron riveted to angle-iron. 
 The end boxes are provided instead with f-inch perforated J-inch iron 
 plate. 
 
 The details of the plant are shown in Figs. 7 to 11.* The ele- 
 vator is not of the best type ; the manager does not recommend it. 
 The T-piece and blind flange mean an unnecessary resistance to the 
 water. The best form approximates that to be described later on as 
 in use at some of the newer mines on the Clutha river. The con- 
 nection between the pressure-pipe and the elevator should take place 
 along a greater angle, since the less the deflection of the water the 
 greater the efficiency obtained. 
 
 The striking-plate is a casting 24 by 24 inches by 3 inches thick. 
 The head-box is lined with No. 12 boiler-plate to protect the wood- 
 work against the stones deflected from the striking-plate. 
 
 It is not found necessary to use deflectors with the nozzle. The 
 usual feathers shown in section A B, Fig. 10 for keeping the 
 water from scattering, are provided. The ball-joint with pin per- 
 mits the vertical movement of the director. Instead of the universal 
 joint which is so apt to get jammed, a large holding-down bolt regu- 
 lates the horizontal motion. 
 
 The manager of the Blue Spur has designed a new form of riffle. 
 The angle-iron on angle-iron is a riffle which entails a great waste of 
 material, to avoid which a reversible form would be advantageous. 
 This is shown in Fig. 12. The eight bars are not riveted each sep- 
 arately, as is usual, but rest upon mortices or recesses in the two 
 lateral retaining-bars, and are kept in position by the two bolts as 
 indicated. In this way, when the edge of one side of the riffle bars 
 becomes worn out, it is but the work of a few minutes to loosen the 
 bolts and reverse the bars. With such an arrangement it is neces- 
 sary that the bars should be accurately cut, otherwise they do not 
 remain firmly in place. 
 
 While the plant at the Blue Spur is by no means the best in Otago, 
 yet the following record, given to me by the manager, shows that 
 very good work is done here. 
 
 In working a face of tailings, 55 feet high,f 26,929 cubic yards 
 
 * Traced from the original of Mr. Howard Jackson, the Manager, who kindly 
 granted permission. 
 
 f The tailings have consolidated by reason of the cement of the original de- 
 posit, which they contain, and present the character of ordinary wash. 
 
ALLUVIAL MINING IN OTAGO. 
 
 11 
 
 were raised and dumped a height of 87.8 feet in a period of 680 
 hours. 
 
 The yield obtained was 115 ounces, 11 pennyweights, 16 
 
 grains, worth 433.8.9 
 
 The working cost included 3 men, . . . 89.5.0 
 
 Two liners worn out, ..... 10.4.0 
 
 Add to this for depreciation of plant, manage- 
 ment, etc., 99.9.0. 
 
 The total cost was, 198.18.0 
 
 Leaving a profit of, 234.10.9 
 
 The value of the material was 5.6 pence per yard or 3} pence per 
 ton. 
 
 The cost of working was 1.77 pence per cubic yard or 7.78 pence 
 per ton. 
 
 F'g. 12. 
 
 CROSS-SECT.IO'N A.A. 
 
 RIFFLE WITH REVERSIBLE BARS 
 
 CROSS-SECTION B.B. 
 
 The water used with 2 elevators and 1 nozzle, was as follows : 
 
 No. 1 Elevator, 450-ft. head. Pressure 1 93 pounds per square 
 inch. 8f sluice-heads.* 
 
 No. 2 Elevator, 375-ft. head. Pressure 164 pounds per square 
 inch. 10 sluice-heads. 
 
 Nozzle, 375-ft. head. Pressure 164 pounds per square inch. 3f 
 sluice-heads. 
 
 The gold won from the sluice-boxes was 97 ounces, 16 penny- 
 weights, 18 grains, worth 366 17s. Wd. 
 
 Pickings from the "reef" or rim-rock, 17 ounces, 14 pennyweights, 
 22 grains, worth 66 10s. llcZ. 
 
 The latter gold was imbedded in the crevices of the schist which 
 forms the bed rock. 
 
 f A sluice-head of water equals theoretically 1 cubic foot per second ; in practice 
 it is usually calculated at 50 cubic feet per minute. 
 
12 
 
 ALLUVIAL MINING IN OTAGO. 
 
 Considering that this work was done under the disadvantages of 
 a much worn and by no means first-rate plant, it is needless to em- 
 phasize the good results obtained in so far as economy of handling 
 is concerned. 
 
 It so happens that at the North Bloomfield claim, in California, the 
 elevator was used under conditions which render interesting a com- 
 parison. There a more elementary type of elevator was in use, the 
 jet not being a part of the machine itself, not even inserted inside 
 the mouth-piece, but so placed as to shoot up the line of the elevator 
 pipe. There one elevator lifted gravel a vertical height of 87 feet ; 
 here two elevators raised the material in two lifts of 31.8 and 56 
 feet respectively to a total height of 87.8 feet. At the Blue Spur a 
 nozzle with a head of 375 feet and delivering 3f sluice-heads (or 
 5400 cubic feet per 24 hours) did the work of breaking down the 
 bank, which at the North Bloomfield was done by a stream of 800 
 miners' inches (or 1, 784,000 feet per 24 hours), under a head of 
 450 feet. Other figures are as follows : 
 
 Height of face of gravel, 
 Diameter of elevator-pipe, . 
 
 At the throat, 
 
 Diameter of jet, . , 
 Water used in the elevators, 
 
 Under a head of . r 
 
 Capacity of the plant per 24 
 
 hours, . '' . ' . ' l{ ". r 
 
 Blue Spur. 
 55 feet 
 15 inches. 
 6 inches. 
 2 inches. 
 18| sluice-heads 
 or 27,000 cu- 
 bic feet per 
 24 hours. 
 410 feet. 
 
 North 
 Bloomfield. 
 
 135 feet. 
 22 inches. 
 14 inches. 
 6 inches. 
 1400 miners' inches 
 or 3,122,000 cubic 
 feet per 24 hours. 
 
 530 feet. 
 
 1000 cubic yards. 2400 cubic yards. 
 
 The wear and the tear at the North Bloornfield was found so 
 excessive that the use of the elevator was discontinued. Under the 
 conditions which obtained there, nothing less than 25 cents per cubic 
 yard would pay.* 
 
 The Island Block. A modern plant may be seen at the Island 
 Block, where three elevators are at work. The nature of the deposit 
 was described in my former paper as an old channel of the river 
 Molyneux or Clutha. At the time of my visit, the face of wash was 
 40 to 51 ft. high, the top-gravel being poor but not absolutely bar- 
 ren, while the " pay" consisted of the lowermost 10 to 15 feet. The 
 
 * This information I owe to Mr. W. H. Kadford, formerly superintendent of 
 North Bloomfield. 
 
ALLUVIAL MINING IN OTAGO. 13 
 
 gold is accompanied by a large amount of fine black iron sand, the 
 bulk of which, on cleaning up, is collected with a magnet. The 
 nuggets found in alluvial mining elsewhere are unknown here, for 
 the precious metal occurs in rounded flakes, of a fairly uniform size 
 and rarely more than T 3 5 inch in diameter. The wash contains 
 numerous pebbles of what the. miners call " black maori," a sort of 
 siliceous wad,* resulting from the hydration and oxidation of rho- 
 donite, the silicate of manganese. The transition can sometimes 
 be observed. The quartzose schists form the bed-rock, but are not 
 represented by any large boulders, their easy degradation having 
 produced the small angular quartz stones, the sand and the dark 
 blue silt which form so large a proportion of the wash. 
 
 A plant of unusual excellence has been erected here. The bed- 
 rock being below the level of the river, the wash is raised by hy- 
 draulic elevators into sluice-boxes, a lift of 40 to 60 ft. To do this 
 work, water is taken from a stream named the Fruid burn, and con- 
 ducted through pipes of lap-welded steel, until it arrives at the 
 elevators, where it comes under a head of 760 feet. Starting from 
 the penstock or pressure-box with a double main, each branch having 
 a diameter of 16 J inches, the water, after 17 chains, is delivered 
 into a single pipe which for 27 chains has a diameter of 16 \ inches, 
 to be reduced to a pipe 15 inches diameter, which conducts it to the 
 immediate vicinity of the heading when a final reduction to 9 inches 
 diameter takes place. The discharge or uptake pipe of the elevator 
 is 15 inches and the jet is 2J. The material lifted per elevator 
 varies with the character of the gravel from 30 to 40 tons per hour. 
 The lap-welded steel pipes are all manufactured in England. Their 
 thickness varies from J to ^ of an inch, the greater thickness is 
 found to make them too heavy and the lesser is far more than equal 
 to any strain to which they may be subjected. They are said to have 
 been tested up to 1000 pounds per square inch previous to being 
 sent out. The price of these pipes varies from 8s. 2d. per foot for 
 15-inch pipes to 4s. Sd. for 11 inch ; but the average has been about 
 6s. Qd. for the 15- inch pipes, of which the greatest length has been 
 used. This figure should not prevent their extensive use on the 
 part of companies desirous of erecting a first-class permanent plant. 
 
 All the joints are faced with the lathe and the pipes are in 18 feet 
 lengths. Of course such lap-welded pipes severely test the joints, 
 the excess of pressure on which is not relieved, as is ordinarily 
 
 * As was pointed out to me by Professor G. H. F. Ulrich, now of the University 
 of Otago. 
 
14 
 
 ALLUVIAL MINING IN OTAGO. 
 
 the case, by leakage along rivets. The pattern adopted is the 
 Kimberly (see Fig. 13). 
 
 A is a loose angle-iron flange which is slipped on before the ring 
 B is shrunk on to the pipe. This arrangement is very convenient, 
 since the bolt-holes in the flanges can be made to fit without all the 
 trouble of turning a length of pipe. . The drawback to this form of 
 joint consists, however, in the fact that for rough country it is not 
 well adapted, since with any movement the shoulder is apt to slip 
 out of its recess, producing a leak. For fairly straight, permanent 
 lines it is most desirable. 
 
 The wash is thrown by the elevators into sluice-boxes of Kauri 
 pine, 3 feet wide, 1 foot deep, and in lengths of 12 feet. Old 40- 
 pound rails are used to support them. (See Fig. 14.) They are 
 
 Fig. 13. 
 
 Sackir 
 
 Fig. 14. 
 
 
 T 
 
 
 
 
 
 LLHr" 
 
 [W 1 
 
 
 
 1 
 
 
 *F> Sheet 
 
 Iron ^ ]lV 
 
 s 
 
 OC^J^, ! Rail 
 
 KlMBERLEY FLANGE 
 
 SLUICE-BOXES 
 
 lined with thin sheet-iron, and set at a grade varying with the mate- 
 rial treated, the average being 8 inches per 12 feet. With the 
 " stripping" or uppermost layers of " wash," this is increased to 9 
 inches ; and, on the other hand, the last few boxes of a series are 
 inclined at from 7 to 7J inches only. Sacking (common bags, ripped 
 up) is put along the bottom of the upper boxes, underneath the riffle 
 bars. The riffles are of the usual form, angle-iron riveted to angle- 
 iron. After a varying distance 100 to 150 feet of ordinary riffles 
 there succeeds a series of " under-currents" or false bottoms. These, 
 like the " grizzly, " or sizing-bars of a stamp-mill, serve to separate 
 the larger boulders from the finer, richer wash. In their arrange- 
 ment a set of iron-bar riffles follows the ordinary angle-iron riffle ; 
 that is to say, the first bar (of a set of flat iron bars, T ^- inch apart) 
 is placed upon the last bar of angle-iron, so as to form a sieve or 
 false bottom through which most of the fine wash finds its way. 
 
 The false bottom is placed at a less inclination than the sluice-box, 
 and as a consequence, the depth increases gradually until, at the end 
 
ALLUVIAL MINING IN OTAGO. 15 
 
 of two 12 feet sluice-boxes the distance between the riffles and the 
 bottom is 4 inches. In this length of 24 feet a succession of vari- 
 ous forms of riffles is employed. First come the iron-bar riffles 
 already noted, for a length of 4 feet. These are found very effective 
 in saving the fine gold. Then come two sheets of perforated iron, 
 followed by a ' blank " or piece of plain, ordinary iron plate. This 
 last is put in to economize the water, so much of which would other- 
 wise pass through into the under-current that the remainder would 
 be insufficient to carry forward the coarser material. This blank is 
 above the lower end of the under-current and is followed by a suc- 
 cession of ordinary angle-iron riffles, to be again followed with 
 another separation by a second under-current. In this way the wash 
 is sized, the coarse passing on, while the finer, more auriferous gravel 
 is treated apart, in the "side-runs " to be described later on. 
 
 The upper sluice-boxes are lined, as I have said, with ordinary 
 sacking; but from the top of the first under-current, cocoanut mat- 
 ting is substituted, linen being placed underneath. The heavy, 
 black iron-sand containing the gold finds its way through the mat- 
 ting which serves so well to arrest it and lies upon the linen which 
 covers the wood- work. The total length of sluice-boxes varies from 
 200 to 300 feet, according to the changes in the coarseness and rich- 
 ness of the wash. 
 
 At the end of the under-currents, the finer gravel which has thus 
 been separated, is diverted into "side-runs" or "streamers." These 
 are tables placed by the aide of the main line of boxes in order to 
 effect the collection of gold. The arrangement comprises two tables 
 (See Fig. 15), each 3 feet broad by 24 feet long, placed at a grade of 
 10 inches in 12 feet. They are ordinarily covered with cocoanut 
 matting ; but when washing the residues obtained from the clean-up 
 of the sluice-boxes, the uppermost 4 feet are covered with green 
 baize. Plush was tried for this purpose but it was found that the 
 large quantity of black sand choked it. Of such a pair of "side- 
 runs," one is used at a time; the inlet in the delivery-box being 
 closed with a piece of sheet-iron. The material is diverted from one 
 table to another every two to four hours, depending upon the fine- 
 ness and richness of the gravel. In cleaning up, most of the black 
 iron-sand is removed while wet by the use of the magnet ; after dry- 
 ing, some of the lighter impurities are eliminated by blowing. The 
 "blowings" and the iron-sand are treated in an amalgamating 
 barrel. This is the only use made of mercury. With the aid of 
 electric lights at night, work goes on through the twenty-four hours 
 uninterrupted. 
 
16 
 
 ALLUVIAL MINING IN OTAGO. 
 
 The Roxburgh Amalgamated. Twenty miles up river from the 
 Island Block is Roxburgh, where several large hydraulic plants 
 are at work. The Roxburgh Amalgamated Company's claim 
 is on the east bank, facing the town, near the mouth of Teviot 
 creek, and at the lower end of Coal Creek flat, through the 
 western portion of which the river has cut its way. That part 
 of the claim bordering upon the Clutha was originally worked 
 by the diggers with good success, first by ground-sluicing and 
 afterwards by means of a primitive dredge. Though this part of 
 the huge deposit which forms Coal Creek flat has been considered 
 the best, because also the only portion available for work, there is 
 reason to believe that old river-channels may yet be found in the 
 
 Fig. 15. 
 
 SIDE-RUNS 
 
 form of deep leads. At the time when I was in Roxburgh, the 
 Company was engaged in opening up the high terrace ; but since 
 then the manager* has discovered a lead some distance back in the 
 flat ; and the elevators have made an average monthly output of 250 
 ounces. The gold is confined to the lowest 3 feet, the top-gravel 
 being absolutely barren. This fact, only recently ascertained, is 
 contrary to the previous general opinion that these river-terraces were 
 more or less gold-bearing through their entire thickness. 
 
 Because of its proximity to the river, the claimf is subject to 
 
 * Mr. Rene" Proust, to whom I am indebted for this later information, as for 
 courtesy in every other way. 
 
 f The New Zealander calls that part of the claim which is blocked out and 
 being worked, a " paddock." 
 
ALLUVIAL MINING IN OTAGO. 17 
 
 flooding when the river is high. For this reason, at the time of my 
 visit, only one out of three elevators was at work. The face of wash 
 consisted of a barren over-burden of 39 feet lying upon 20 feet of 
 auriferous material. The 59 feet of material thus necessarily to be 
 moved was handled by three elevators, each having approximately the 
 following dimensions : 
 
 Supply or pressure-pipe 11, uptake or elevator-pipe 17 inches in 
 diameter. Liner narrowed at the throat to 11 inches. Jet of No. 
 
 1 has 3, each of the other two 2J inches, diameter. 
 
 Elevator No. 1 was lifting to a vertical height of 37 feet. No. 
 
 2 to 28 feet ; and No. 3 to 25 feet. 
 
 Of the directors, monitors or nozzles, which break down the face 
 before its removal by the elevators, each has a 2J inch nozzle and 
 is connected bv a 7-inch pipe to an 11-inch supply-pipe which 
 in turn joins to the 18-inch main. There are 16 chains of 18-inch 
 pipe and then 48 chains of 22-inch pipe, which bring the water 
 from the penstock.* This last is 14 by 10 by 12 feet and is connected 
 in turn with a flume 2J miles long, leading to the supply-dams. 
 The flumes, built of Kauri pine, is 3 feet deep and 3 feet wide, hav- 
 ing a gradient of 9 inches to the chain. 
 
 The head of water available at the claim is 600 feet and 22 
 sluice-heads were in use at the time of my visit out of the total of 
 75 heads, said to be the largest water-right in New Zealand, and the 
 equivalent of 3750 cubic feet per minute. 
 
 At the present time, as already stated, the pay-gravel is confined 
 to 3 feet only; and to remove the barren over-burden, the elevators 
 have 10-inch liners, 18-inch uptake-pipes and 3-inch jets. This, the 
 " stripping elevator," is shown in position in Fig. l.f The side and 
 back-views (Figs 2 and 3) explain themselves. The face of wash 
 is broken by 3-inch nozzles. This plant is removing 590 tons per 
 elevator per 8-hour shift. Three men per shift per elevator are em- 
 ployed, the wages for the three amount to 22s. so that the actual 
 handling of the gravel costs less than one-half penny or 1 cent per 
 ton. On reaching the " pay dirt " a smaller elevator is used, having 
 a 2-inch jet, 8-inch liner and 15-inch uptake pipe. By this form of 
 machine the gold-bearing material is more quietly and carefully 
 handled than the over-burden of barren gravel. 
 
 At the present time 45 sluice-heads are in use, so that each eleva- 
 
 * Called in California the " bulk-head " or pressure-box." 
 f These drawings I owe to the courtesy of Mr. Rene* Proust, a member of this 
 Institute, and engineer of the company. 
 
 2 
 
18 ALLUVIAL MINING IN OTAGO. 
 
 tor, with its driving-nozzle, uses about 15 cubic feet per second, 
 under a pressure of 250 pounds per square inch. 
 
 The sluice-boxes 3 feet wide, 18 inches deep and 12 feet long, are 
 supplied with ordinary angle-iron riffles. The grade is 6 inches per 
 12 feet for elevator No. 1, 8J inches for No. 2, where the gravel is 
 notably coarser, and 7 inches for No. 3. 6 inches is found to be 
 best adapted for the general run of the material treated. 
 
 It is intended to erect " side-runs," the tables to be 20 feet broad 
 and supplied with wells or traps to hold mercury. The manager is 
 fully alive to the difficulty of arresting the extremely fine, flaky gold 
 by purely mechanical means. The gold occurs here, as at the Island 
 Block, in fine flakes mixed with black iron-sand. On cleaning up, 
 a great deal of lead in the form of shot is found.* 
 
 At this mine the hydraulic elevator has been adapted to various 
 uses in a very ingenious manner. A common difficulty in placing 
 an elevator in position is that the sinking of a hole to receive the 
 foot of the elevator is attended with delay and trouble owing to the 
 running in of wash and water. This has been overcome by design- 
 ing a special form known as the "sinker," and shown in Fig. 16, 
 where it will be seen that the intake-pipe has a swivel-joint which 
 enables it to be readily accommodated to an uneven bed-rock. With 
 this machine a place may be rapidly prepared for the erection of a 
 larger elevator. 
 
 At the Waipori Deep Lead, at Waipori, an old bed of the Lam- 
 merlaw Creek is worked. The gravel deposit is 54 feet deep and 
 from 25 to 30 feet wide. It was first worked by means of a " Cali- 
 fornia pump " and later by means of a steam-winch. Ten thousand 
 tons of gravel yielded 79 ounces of gold, worth 295, and this test 
 was considered sufficiently satisfactory to warrant the erection of an 
 elevator-plant. The water comes under a head of 390 feet and the 
 proprietors have the right to 27 sluice-heads. The ditch, 5 feet by 
 2 feet, is constructed to carry 18 heads and has a gradient of 8 feet 
 per mile, being constructed at a cost of 25 shillings per chain or 
 100 per mile. The ground is soft, being composed of a dense, 
 peaty sod which is readily cut. 
 
 Where fluming is necessary, it has been built of 1-inch Ribo or red 
 pine, and 3 by 2 feet in size. The fluming, not including trestles, 
 costs Is. 3d. per foot. From the penstock there are 6100 feet of 
 piping, of which 2000 is 18-inch pipe (No. 14 gauge), and the 
 
 * This lead has been expended upon the curse of the country the rabbit. 
 
ALLUVIAL MINING IN OTAGO. 
 
 19 
 
 remaining 4000 feet, 15-inch pipe (No. 12 gauge). The pipes are 
 double-riveted and provided with the usual air-valves at top of 
 bends, mud-cocks in hollows and expansion- valves along straight 
 courses. 
 
 The supply-pipe leading from the main is 11 inches in diameter, 
 reduced to 9 before delivering the water at the jet of the elevator. 
 This last differs from the ordinary type in being fitted with Robert- 
 son's patent atmospheric jet (see Fig. 5). The dimensions are: 
 hopper, 16 inches; throat, 6 inches, with a 2|-inch nozzle and a 12- 
 
 Fig. 16. 
 PORTABLE RAPID SINKER 
 
 FOR 
 HYDRAULIC ELEVATOR 
 
 inch uptake-pipe. The director, which breaks down the face of the 
 gravel, is supplied by a 7-inch pipe. The brasses are 2 and 1 j 
 inches respectively. 
 
 The material is delivered into sluice-boxes of the ordinary type 
 12 feet long, 3 feet wide, and 1 foot deep. The sides of the head 
 or delivery -box are raised to 2 feet 6 inches. The first box receives 
 1 inch ; the second, 3 inches ; the third, 5 inches ; the fourth, 6 J 
 inches of fall per 12 feet. The rush of water keeps the first box 
 clear. The average grade of the remaining boxes is 6J inches. 
 
20 ALLUVIAL MINING IN OTAGO. 
 
 Ordinary Venetian or "angle-iron on angle-iron " riffles are in use, 
 and under them is placed common sacking. The end-boxes, and 
 the first also, are supplied with perforated iron plate. The last two 
 are lined with blanketing. Of the total gold obtained, 2 per cent, 
 only is found below the first box. 
 
 At present, the uptake-pipe being 87 feet long, the vertical height 
 lifted is 56 feet from the hopper, or 58 feet from the bed-rock. By 
 utilizing the suction* another 10 feet will be available, making 66 
 feet in all. This lift is, in proportion to the power available, unusu- 
 ally high, but it has in no way tested the "aero-hydraulic" ele- 
 vator, which is constructed to work under water and not under the 
 conditions which obtain here. At the Golden Point mine, five miles 
 away, I had an opportuity of noting the assistance which the addi- 
 tion of the " atmospheric jet " gave to the ordinary elevator. There 
 the head of water available is 103 feet, supplied through an 11-inch 
 pipe. The water-jet is 2f inches in diameter, while the uptake-pipe 
 is 9 inches. With this force the ordinary rough wash was lifted to 
 32 feet, the work of breaking a 12-foot face being done by a 2J-inch 
 nozzle. Under ordinary conditions, the common elevator would not 
 lift higher than 10 to 15 feet with a head of 103 feet. 
 
 The atmospheric nozzle or jet is an improvement on the simple 
 elevator; since it acts on the principle that by lightening the load 
 you increase the effectiveness of the column of water.f In working 
 elevators a waste of power is caused by what is known as " flood- 
 ing;" that is to say, the water from the face, running into the basin 
 in which the elevator stands, accumulates there upon the least stop- 
 
 * By adding a length of pipe to the hopper of the elevator. 
 
 f The results of the following experimental tests were given to me by the in- 
 ventor : 
 
 No. 1. 2 gallons of water were pumped in 20 seconds with air. 
 
 No. 2. 2 gallons of water were pumped in 32 seconds without air. 
 
 Pressure in the above experiments 35 pounds per square inch. 
 
 No. 3. 2 gallons were pumped in 2 minutes with air. A trial was made with- 
 out air with the same quantity of water and no work was done. Pressure, 8 pounds 
 to the square inch. 
 
 No. 4. 10 gallons were pumped with air in 1 minute, 30 seconds. 
 
 No. 5. 10 gallons were pumped without air in 2 minutes, 10 seconds. 
 
 In this test 5| gallons were required to pump the 10 gallons with the air, and in 
 pumping without air it took 10 gallons to do the same work. Pressure, 38 pounds 
 per square inch. Sand, shot, spelter, etc., were lifted in the proportion of half solid 
 matter to half water. 
 
 It was found that the machine emptied a given quantity of water with air faster 
 than without air in the ratio of 1 to 1.33. 
 
ALLUVIAL MINING IN OTAGO. 21 
 
 page,* and the hopper being soon under water the air is entirely 
 shut off. Similarly, when the hopper is intermittently under water, 
 the unequal irregular suction produces a fusilading of the piping 
 by the pebbles, which is productive of great wear and tear. It is 
 found that the admission of a little air, by keeping the hopper 
 partly open, cannot be controlled, though it is desirable in that, 
 while increasing the wear on the liner, it adds to the effectiveness 
 of the machine. To avoid those difficulties and to obtain these 
 advantages, there is introduced a constant air-supply by means of 
 the addition shown in Fig. 5. An annular air-current passes from 
 the outer air through a jet supplied by a pipe which extends above 
 the water-line. This forms an air cushion round the water-jet and, 
 by preventing it from feathering or breaking, tends to maintain a 
 uniform velocity. The diminution of the suction is not sufficient to 
 affect injuriously the feeding, while the lightening of the column 
 aids the effectiveness of the machine. There is also a decrease in 
 wear and tear, since the admission of a constant air-supply secures a 
 constant speed to the ascending column of gravel and water. 
 
 Before leaving this part of the subject, a few general conclusions 
 may be in place. The alluvial deposits df Otago are of remarkable 
 extent, more particularly the lake- and river-beds along the course 
 of the Clutha, Shotover and Kawarau rivers. These latter were not 
 to any large extent accessible for mining previous to the introduc- 
 tion of the elevator, because the frequent rapid rise of the rivers pre- 
 vents the satisfactory use of the dredge, and ordinary sluicing is 
 rarely possible owing to the want of "dump. " The most extensive 
 deposits are in the flats formed from old lake-basins ; but their level 
 is such that the seepage from the river rapidly floods the miner's 
 claim. To overcome the difficulty by ordinary pumping was not 
 economically practicable. The hydraulic elevator, however, renders 
 these deposits available for exploitation, and its introduction is rap- 
 idly spreading ; the expense of the first installation of the costly 
 plant required being met by the consolidation of small claims under 
 companies provided with the necessary working-capital. 
 
 The elevator will have a great future in Otago; but, in the haste 
 to use a new machine, there is a tendency to discard the assistance 
 of methods which have previously rendered good service. Ground- 
 sluicing has been put aside, and there is a tendency to make the ele- 
 vator do work which can sometimes be less expensively done by 
 
 * As when a large stone sticks in the throat of the elevator. 
 
22 ALLUVIAL MINING IN OTA GO. 
 
 simpler means.* In the blocking out of ground there is room for 
 improvement. It is not very difficult to erect a good plant, and it 
 is easy to commence the attack on a face of gravel, but the syste- 
 matic blocking out of the claim tries the resources of those whose 
 experience has been mainly confined to other forms of mining. 
 
 DREDGING. 
 
 The first gold-seekers who prospected the sands of the Shotover 
 and Molyneux rivers restricted their search to the easily accessible 
 deposits which had accumulated under the shelter of rocky bars ; and 
 when the auriferous sands were found to extend under the waters of 
 the river, they turned the stream by means of wing-dams. The rich 
 alluvium was found, however, in places where this mode of opera- 
 tion was impracticable or too costly, and in such places, standing 
 shovel in hand, they snatched with difficulty the golden sand, which 
 increased in richneas the less accessible it became. The simple 
 shovel was useless in a fast current ; hence the next step was to con- 
 trive a ladle or spoon with which to scoop up the river-bed. A piece 
 of hide fastened to an iron rim was arranged behind the modified 
 blade of a shovel, and this at the end of a long pole helped to in- 
 crease still further the area available for work. Soon, however, the 
 distance from the shore, and with it the increasing depth of water, 
 prevented further advance. A barge or punt was then built, the 
 pole was lengthened to 20 feet or more, the scoop was enlarged so as 
 to hold a barrowful, and, the increased weight requiring other than 
 mere hand-labor, a winch and tackle were rigged up. This now 
 became the "spoon-dredge," the forerunner of the numerous types 
 of bucket-dredges which have started a new branch of the mining 
 industry of New Zealand. 
 
 The spoon-dredge served its purpose, but the numerous mines 
 along the banks of the river had begun to send down tailings, which 
 soon covered the bottom with a rapidly increasing thickness of 
 valueless material. The spoon-dredge was not capable of coping 
 with this fresh difficulty, but the rapidly flowing river suggested the 
 greater power now needed to replace human muscle; a water-wheel 
 took the place of the winch, and the " current- wheel -dredge" was 
 invented. This consisted of a simple form of bucket-dredge, worked 
 by an under-shot wheel placed at the side of a punt. The power 
 needed to propel the machine severely restricted its usefulness, for it 
 
 * By this I refer particularly to the removal of the barren overburden, which 
 can be done by ordinary ground-sluicing. 
 
ALLUVIAL, MINING IN OTAGO. 23 
 
 could not be employed in the back-waters, or indeed anywhere but 
 in the full force of the river-current, and the richest parts of the 
 channel had therefore to remain untouched. Steam was substituted 
 for water-power, and the bucket-and -ladder type of dredge was ad- 
 vanced a stage further by the addition of revolving sizing-screens, 
 winches for mooring and pumps for raising the water required to 
 separate the fine gold-bearing silt from the coarse gravel. This 
 brings us down to to-day, when the river-sands and the sea-beaches 
 of the South Island are worked by a force of over 50 dredges, pro- 
 pelled by water, steam and electricity. 
 
 When I was. at Duuedin, in 1890, it was difficult to find a man 
 who had not located some acres of land on river-bank or sea-shore. 
 Dredging properties were plentiful as " leaves in Vallombrosa 7 ' and 
 " the potentialities of acquiring wealth beyond the dreams of ava- 
 rice" were offered on every hand. Returning in March, 1891, I 
 found that the number of dredges at work had largely increased, 
 with a corresponding diminution in the dredging fever. The results 
 had been disappointing. 
 
 The success of the Dunedin dredge was the main cause of the 
 dredging fever. Directed by a man of great experience in this 
 branch of engineering, and put to work in a part of the river 
 Clutha which soon proved very rich, this dredge returned in ten 
 months two-thirds of the paid-up capital of the company which 
 owned it. One of the Shotover dredges had also been fairly suc- 
 cessful, while on the sea-beach the Wai papa dredge, exploiting the 
 titaniferous gold-bearing sand, had made, under many difficulties, 
 very encouraging returns. It was at once found that the extent of 
 ground available for this mode of working was almost unlimited ; 
 the river-channels and the sea-coast were soon covered with loca- 
 tions; claims were taken up and floated into companies, the vendor 
 receiving, for ground which had cost him but a few shillings, a large 
 sleeping interest in a concern to the working capital of which he 
 contributed nothing. Large areas were assumed to be valuable on 
 account of reported rich yields obtained by the diggers from spots 
 representing a very small proportion only of the total field to be 
 worked. No tests, or only unsystematic tests, were made. It was 
 overlooked that the rapid rise of the river would prevent work 
 during many months in the year. Moreover, in this form of mining 
 the experience so far accumulated had been but small, and the saving 
 of the gold was often attempted under conditions which were hope- 
 less. Gradually the enterprising investor awoke to the stern fact 
 
ALLUVIAL MINING IN OTAGO. 25 
 
 that, like all other branches of mining, dredging required judgment, 
 care and experience. 
 
 I will here describe two representative bucket-dredges. Figs. 17 
 and 18* show the general mode of construction. The pontoon in 
 this case has a length of 80 feet, a width of 18 J feet, and a depth 
 of 4J feet. The ladder is constructed to work to a depth of 20 
 feet below the surface of the water. The power to propel the 
 machinery is derived from the river, and is transmitted as elec- 
 tricity. 
 
 The Dunedin dredge is working the bottom of the Clutha at a point 
 ab9ut 3 miles above the town of Roxburgh. The deposit covering 
 the rocky bed of the river consists here of 20 to 25 feet of barren 
 drift, overlying a thickness of 2* to 2J feet of gold-bearing wash. 
 Sometimes the " pay " thins to 6 inches. The overburden of drift 
 consists of small-sized gravel, but the pay- wash is composed of large 
 boulders, among the interstices of which occurs the gold. Black 
 sand is found in both drift and pay-wash, that of the drift originat- 
 ing, together with the bulk of the material in which it occurs, from 
 the mines along the river. The gold is similar to that obtained else- 
 where along the Clutha, consisting of fine, flat flakes in a black iron- 
 sand. Gold is not seen in the quartz of the pebbles. 
 
 This dredge has a double ladder of buckets holding 2 cubic feet 
 each, 12 emptying per minute on each side, giving the machine a 
 capacity of 106 cubic yards per hour. There are 31 buckets on each 
 side, the material from which passes through the two perforated 
 iron cylinders, the larger pebbles being ejected along an iron shoot 
 which returns them to the river, while the fine gravel passes over a 
 table 8 feet long by 7J feet wide. The grade is 2 inches per foot, 
 and cocoanut matting is used to arrest the gold. This table and the 
 similar one on the other side discharge upon a middle table, 8 feet 
 long by 4 feet wide, which is provided with iron-bar riffles. From 
 here the gravel falls into the river. The above comprises the whole 
 apparatus employed in the saving of the gold. The cocoanut mat- 
 ting is washed at regular intervals in a tank, the gold being subse- 
 quently separated from the black sand by panning. 
 
 The motive power for the machinery is derived from steam, the 
 fuel used being the lignite which occurs at Coal Creek, 3 miles up 
 the river. The price is 8 shillings per ton, delivered at the bank, 
 
 * The drawing I owe to the courtesy of Mr. Kobert Hay, C.E., of Dunedin, who 
 has designed many of the best dredges in use in Otago. 
 
26 ALLUVIAL MINING IN OTAGO. 
 
 whence it is ferried by boat. The daily consumption is 3 tons. 
 Electric light enables work to be uninterrupted. 
 
 The dredge had just re-started at the time of my visit, after a 
 stoppage due to the rise in the river, which was even then flowing 9 
 knots per hour. During flood-time the rate of flow reaches 12 knots, 
 while the average is 7 knots per hour. The working expenses are 
 250 per month, This includes the wages (160) of 9 men and a 
 dredge-master. The coal bill is 30. The balance of the 250 is 
 taken up by repairs and supplies. The average of steady work is 
 only 4 days per week of 6 working days. This does not allow for 
 the interruption, often for weeks, due to floods. From December, 
 1889, to October, 1890, dividends amounting to 4080 were paid on 
 a nominal capital of 7200, and a 'paid-up capital of 6240. After 
 October, work ceased on account of the spring floods until the first 
 week in December. The directors' report for the 6 months ending 
 July 2, 1890, states that the gold obtained amounted to 884 ounces, 
 5 pennyweights, 8 grains, value 3316 out of which 1680 was 
 returned in dividends. 
 
 The Dunedin dredge is working the auriferous gravel lying upon 
 the rock-bed of the swift-flowing Clutha ; but the Waipori dredge, 
 which we will next consider, is placed under much more favorable 
 conditions. The Waipori river is a small stream, running through 
 a flat valley surrounded by rolling foot-hills. A wide deposit lies 
 in the hollow of the valley, and above it flows the present stream. 
 The gold obtained does not lie upon the bed-rock of the original 
 channel, which is much deeper, but at a horizon marked by coarse 
 sand the (t false bottom" of the miners. 
 
 The dredge is of the bucket-and-ladder type. The stream is cf 
 insufficient depth to float it ; but the dredge makes its own water- 
 way by the removal of the gravel. The capacity is 7600 cubic 
 yards per week of 125 to 130 working hours. The movement of 
 the pontoon is directed by 4 winches operating wire ropes fastened 
 to the shore. The engine is of 40 horse-power, supplying the power 
 necessary to work the buckets themselves, as well as the pump which 
 gives the water necessary for the tables. The contents of each bucket 
 as it comes up are emptied into a revolving sizing-cylinder, con- 
 structed of horizontal iron bars. The fine silt goes straight to the 
 tables, while the coarse passes to another sizing-cylinder (this time 
 of perforated boiler-plate), which separates the coarse gravel and 
 boulJers. These fall into the stream from an iron shoot, while 
 the line goes to the tables, which are arranged on either side and 
 are covered with coarse cocoanut matting, with linen underneath. 
 
ALLUVIAL, MINING IN OTAGO. 27 
 
 The following figures will indicate the cost of operations during 
 the period of a year. 
 
 . s. d. 
 Repairs and Alterations, 222 9 1 
 
 This was" chiefly in pins and bushes. The wear and tear is mostly 
 about the buckets. The lips last for two years; and the pins on 
 which the buckets are hinged, have an average life of 3 months. 
 
 . s. d. 
 Wages, . . . 1192 16 4 
 
 This includes the pay of 8 men and 3 boys per day. One engi- 
 neer, one winch-man and one boy to attend to the tables, on each 
 shift, making 6 men and 3 boys per 24 hours. Then there are to 
 be added the dredge-master and a blacksmith. 
 
 . s. d. 
 Material,' . . ; "' 1 " f V 5 . . . . 272 9 5 
 
 This includes the shed on the shore which serves as an office, forge 
 and tool-house. 
 
 . s. d. 
 
 Coal, . . . . . ' ..... 507 12 
 Firewood, . V '. ' >; V ' '''';- .... 377 6 
 
 The wood (manuka) costs 1 15s. per cord. Coal (from West- 
 port) costs 55s. per ton, delivered. 
 
 . s. d. 
 Rent, . * .' -V :* 293 
 
 This is the amount (at 10s. per acre) paid to the government as 
 rent for the claim. 
 
 During the year the first two months were taken up by the erec- 
 tion of the plant and in the remaining ten the gold obtained 
 amounted in value to 3095, 8s. 6d. 
 
 The cost of the dredge, including fees to the engineer, was 3380, 
 14s. 3d. 
 
 The weekly cost upon the ground is 30 for labor, 20 for fuel, 
 or (including repairs) about 65 in all. 
 
 Three typical weekly records are as follows : 
 
 First Week. Yield 21 ounces, 16 pennyweights. Time of actual 
 work 140 hours. 
 
28 ALLUVIAL MINING IN OTAGO. 
 
 Ground lifted 8400 yards. Depth of lift 10 feet. Firewood, 10 
 cords. 
 
 Second Week. Yield 33 ounces, 13 pennyweights, 18 grains. 
 Time 126 hours. 
 
 Ground lifted, 8400 yards. Depth about 13 feet. Firewood, 10 
 cords. 
 
 Third Week. Yield 29 ounces, 12 pennyweights. Time 126 
 hours. 
 
 Ground lifted 7560 yards. Depth about 13 feet. Firewood, 
 10} cords. 
 
 Up to that time the dredge had handled very little virgin ground, 
 the material consisting chiefly of the tailings carried down from old 
 sluicing-claims. Since then it has reached solid ground ; and the 
 results, with the same expense, have reached 50 ounces per week. 
 
 This dredge is working under conditions admirably suited to its 
 capabilities. The working-cost is slight, the amount of capital tied 
 up is very small, the area of the claim is large and the danger of 
 floods nil. The depth at which it is working varies from 10 to 15 
 feet. The " false bottom 7 ' of compact coarse sand enables the buckets 
 to get well under the pay-wash, and avoids a great deal of the wear 
 and tear incident to working upon a rocky bed. 
 
 The material treated, while it is very similar to that of the mines 
 on the Clutha, yet contains gold more shotty than that of the big 
 river-claims. The gold of the Waipori flats came in large measure 
 from the erosion of the neighboring quartz-lodes the O. P. Q. and 
 other reefs. While on the dredge I was shown a round, white quartz 
 pebble, taken that morning from one of the buckets, which was of 
 the size of a hand, and showed several splashes of gold as large as 
 a small-finger nail. Such a find, very unusual in the alluvial mines 
 of Otago, marks the somewhat exceptional conditions under which 
 this deposit was probably formed. 
 
 GOLD-SAVING. 
 
 The methods used are of the crudest kind. There is no doubt 
 that the river receives back more than half of the gold contained in 
 the material raised by the dredge. The tables at Waipori are some- 
 what larger than those of the Dunedin dredge; but in both casesit 
 appears the height of absurdity to think that they can save a large 
 percentage of the fine, flaky gold carried along in such a large flow 
 of water and amid so great a volume of sand and gravel. The 
 report of the Directors of the Dunedin dredge company says that 
 
ALLUVIAL MINING IN OTAGO. 29 
 
 " the dredge-master reports that the gold-saving appliances are all 
 that could be desired." This is the severest satire upon the childish 
 efforts made to save the gold, fully sixty per cent, of which must 
 be a mere passenger through the apparatus designed to arrest 
 it. Over a hundred cubic yards of gravel, together with the water 
 employed to transport it, are in this case handled by the dredge 
 every hour, and of this a very large proportion passes over the sur- 
 face of two tables covered with cocoanut matting whose dimensions 
 are 8 feet by 7J feet. There is no opportunity whatever given for 
 a separation of the gold from the mass of heavy black iron-sand 
 and the sediment in which it is enveloped. The surface over which 
 it passes is far too small, and the distance over which it travels is 
 altogether too short to enable it to be arrested by the simple means 
 adopted. What is collected is in spite, rather than by reason, of 
 the efforts made to catch it, and represents a small proportion only of 
 the gold in the material, the larger part being lifted from the river 
 only to be returned. 
 
 THE USE OF MERCURY. 
 
 The use of mercury is not familiar to the alluvial miner of Otago, 
 as it is to his brethren elsewhere. There exists a curious idea that 
 it will not act in cold weather, due no doubt to the fact that the 
 cleaning up in the mills and mines is invariably done with hot water. 
 Of course there is a substratum of truth in this idea, since amalga- 
 mation is as a rule* retarded by cold and assisted by heat, but within 
 narrow limits only and not to such an extent as to make the fact of 
 any great practical importance. It certainly will not explain why 
 the Otago digger has " left in the cold " one of the best friends of 
 mining all the world over. From an examination of the conditions 
 under which the gold of the alluvium of Otago occurs, particularly 
 in the deposits of the Clutha and its tributaries, I am strongly of the 
 opinion that the use of mercury will have to be resorted to if any 
 large percentage of the precious metal is to be extracted. 
 
 In the case of the elevator-plant the example of California can be 
 followed and mercury placed in the riffles of the sluice-boxes them- 
 selves. Then it requires but an extension of the idea of side-runs, 
 
 * In the mountains of Colorado, at an altitude of 8500 feet, the amalgamation at 
 the stamp-mills meets with no obstacle in winter. On the contrary, it is curious to 
 note that the mill-men of Gilpin county unite in asserting that the cold weather is 
 beneficial to amalgamation, for the reason that warmth thins the mercury and causes 
 it (with the vibration due to the falling stamps) to run off the plates. 
 
30 ALLUVIAL, MINING IN OTAGO. 
 
 preceded by under-currents, to permit the further use of the quicksil- 
 ver in wells or traps. With the dredges the first alteration of existing 
 methods which is demanded is the enlargement of the area over 
 which the material passes. Dredges are now constructed at Dune- 
 din to handle over 150 tons per hour. This requires a very large 
 surface to effect even the roughest separation of the fine gold-hearing 
 silt from the large mass of non-auriferous wash. The Wei man 
 dredge at Waipapa* which is supplied with tables 24 feet by 30 feet, 
 having an incline of }-inch per foot, is designed on common-sense 
 principles and supplies an example to the other dredges of Otago. 
 But even the dispersion of the material over such an enlarged sur- 
 face will not suffice to collect the finer particles of gold. Mechani- 
 cal means must be assisted by chemical ; gravitation must be fol- 
 lowed by amalgamation. 
 
 The fineness of the gold in the New Zealand alluvium may be 
 imagined when it is stated that by actual count it requires six to 
 seven thousand particles of the gold as found on the west coastf to 
 form a grain in weight. It will be said that, as a matter of practice, 
 it has been noted that very little gold finds its way beyond the first 
 strips of matting and that on washing, the bottom strips are seen to 
 collect scarce any.J This is after the fashion of the millman who 
 carefully assays his tailings but fails to note how much gold he is 
 losing in the slimes which are carried down stream to cheer the 
 the hearts of a tribe of Mongolians. The evidence obtained by such 
 tests is an ignis fatuus to the miner, deluding him into a blissful ig- 
 norance of his losses. The fact is that in such cases the gold lost 
 is in an entirely different condition from that saved, and methods 
 
 f This dredge was idle during the time of ray stay in Otago, owing to a change 
 which was being made in its construction. An interesting description appeared in 
 the records of the Mining Conference held at Dunedin in 1890, written by Mr. Jas. 
 Allen, a member of this Institute. This dredge is working the sea-beach, those 
 portions where the titaniferous gold-bearing sand has been concentrated by the 
 action of the prevailing winds. 
 
 J Best known by the Hokitika discoveries. 
 
 $ The following experiments were made at Waipapa: 
 
 First Experiment. The bottom cloths those 16 to 18 feet from the head were 
 washed separately from the remainder, with the result : Amalgam for eight days- 
 top cloths, 89 ounces 16 pennyweights; bottom cloths, 4 pennyweights 5 grains. 
 
 Second Experiment. The second row of cloths from the bottom, that is from 14 to 
 16 feet were separately washed. The amalgam from the top cloths was 90 ounces ; 
 the cloths from 14 to 16 feet yielded 8 pennyweights. 
 
 It is necessary to add here that the produce becomes amalgam only in cleaning 
 up, mercury being used simply in collecting the residues from the washing of the 
 plush which last does the direct gold-saving. 
 
ALLUVIAL, MINING IN OTAGO. 31 
 
 which serve to arrest the latter are entirely insufficient to hold the 
 former. 
 
 The character of the gold is in no way prejudicial to amalgama- 
 tion. In both river-banks and sea-beaches, it is bright, of high carat- 
 age, and not " rusty," or mixed with minerals inimical to mercury. 
 On the other hand its fine flakey character makes it particularly hard 
 to arrest by purely mechanical methods. The thin plates of gold, 
 especially when their edges are turned, as must often happen during 
 the treatment the gravel undergoes, are especially adapted to be 
 transported by water. 
 
 The material used for the gold-saving is cocoanut matting, which 
 withjn certain limits answers admirably. Owing to its porous char- 
 acter, it is usually supplemented by linen placed along the wood- 
 work of the tables or sluice-boxes. Some of the dredges employ 
 plush. The choice is largely a matter of expense. At the Island 
 Block it was found that the plush used in the side-runs caught too 
 much of the black iron-sand and got quickly choked. At Waipapa, 
 with a very large proportion of fine black sand, it answered well. 
 The difference of experience is due probably to the quantity of water 
 used, and the gradient over which the material passed. 
 
 The dredge has added largely to the area available fQr mining 
 operations. In this branch of mining, Otago is opening up a new 
 and important field. The practical result of the experience so far 
 obtained proves that the bucket-dredge, though admirably simple 
 and inexpensive, is best suited to the raising of auriferous alluvium 
 ying upon a " false bottom." Upon a true bed-rock the wear is 
 much increased, and the effectiveness much diminished. Everyone 
 knows how difficult it is to scoop fine gold mixed with gravel under 
 water by the aid of a shovel. It runs off. The bucket of the dredge 
 is a modified shovel. For irregular bottoms, the suction-pump 
 dredge, of which the Welman is a good example, will be found best 
 adapted. In this case a powerful centrifugal pump draws up the 
 water, gravel and gold, delivering them to the le.vel of the tables. 
 At Waipapa, stones 35 to 40 pounds in weight have been sent up by 
 the pump; and it only requires an improvement in construction, 
 giving durability and strength, to render it a most effective machine 
 for this class of work. A dredge thus provided is able to. sweep the 
 bottom clean. After that, the extraction of the gold becomes the 
 great question ; and in this direction, as we have seen, there is a wide 
 margin for improvement. 
 
 Time, however, will remedy these defects, and the Otago miner 
 
32 ALLUVIAL MINING IN OTAGO. 
 
 may meanwhile point with pride to the fact that he has shown the 
 possibility of working the sands of the sea-shore at a profit, when 
 they contain but two grains of gold per ton. 
 
 This concludes my notes upon a mining-field but little known on 
 this side of the equator. The chief lesson it conveys is, that we 
 should seek to profit by the experience of others. Otago has much 
 to learn from California in lode-mining and quartz-milling ; but 
 California would do well to study the steps of Otago in hydraulic 
 elevating and dredging. The miner should be the least conserva- 
 tive of men ; his motto should be " pass it on ;" the same difficulties 
 should never require to be overcome twice; and thus should iu 
 avoided that worst of all wastes, the waste of experience. , 
 
 NOTE BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other errors, 
 or communications for publication as "Discussion," or independent 
 papers on the same or a related subiect, are earnestly invited. 
 
\1 
 
 SUBJECT TO BEVISION. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Development of Colorado's Mining Industry.* 
 
 BY T. A. RICKARD, STATE GEOLOGIST, DENVER, COLO. 
 (Colorado Meeting, September, 1896.) 
 
 THE history of this State is that of one generation. Thirty- 
 six years only have elapsed since the birth of that beneficent 
 industry whose footsteps were the first to traverse the wilder- 
 ness of the prairies and penetrate the solitude of the moun- 
 tains. So soon is history made. The men who halted on the 
 rolling plain where Denver now stands and gazed westward at 
 the snow-clad ranges in eager questioning of their possibilities 
 of golden wealth, have lived to see a noble city built where 
 once their camp-fires burned, and have participated in the 
 discovery of magnificent series of productive mines amid the 
 mountains which seemed at that time the Ultima Thule of their 
 pilgrimage. 
 
 To those who investigate the workings of our complicated 
 mining and metallurgical industries, the story of their evolution 
 from humble beginnings will appear an instructive romance. 
 The record that tells it presents features common to the growth 
 of modern mining regions, but also bears aspects peculiar to 
 those local conditions upon which the development of these in- 
 dustries is so essentially dependent. 
 
 In the summer of 1849 a party of seven Georgians were 
 taking a herd of thoroughbred horses across the continent to 
 California. They reached Camp Lyon, on the Arkansas, in Oc- 
 tober, and, meeting James Dempsey, a government guide, they 
 were persuaded by him that it was too late to cross the moun- 
 tains that season. His advice was followed, and, moving north- 
 ward, they established a winter camp at the junction of Cherry 
 creek and the Platte. Upon a sand-bar, lining the south side 
 of the river, they built two cabins. During the closing months 
 of that year they prospected the alluvial banks of Cherry creek, 
 
 * This paper was subsequently presented before the Colorado Scientific Society. 
 The present version, however, is later in publication, and contains some additions. 
 
2 THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 
 
 but did not penetrate into the mountain canons for fear of the 
 Indians. Gold was found in several places, and particularly at 
 a point 16 miles up the stream. From the feathers of the wild 
 geese which they shot, they made quills, serving as receptacles 
 for small quantities of gold-dust. 
 
 This party consisted of Dr. Russell and his brother, Green 
 Russell, A. T. Lloyd, G. W. Kiker, Charles Kiker and P. H. 
 Clark. Early in 1850 they crossed the range by the Bridger 
 pass and went on to California. They mined near Downieville 
 and were successful. Mention was occasionally made of the 
 gold found in western Kansas when on their way across the 
 plains. The goose-quills were evidenced in proof of the story. 
 In the spring of 185Y they, with others, sold out their inter- 
 ests in California and returned to Georgia. Before separating 
 it was agreed among several of them that in the near future 
 they would form a prospecting party to go to western Kansas 
 and search for gold. 
 
 In May, 1858, eleven of them met at the Planters' House in 
 St. Louis. In addition to the original seven there were present 
 J. A. O'Farrell, three men of the name of Chastine and another 
 called Fields. All save two were old Californians. Having 
 organized, they went to Leavenworth by water and thence to 
 Camp Hariiey along the military road. Late in July they left 
 this frontier post, accompanied by an escort of twenty men 
 under the command of Captain Lyon. In August the party 
 reached the log cabins on the Platte. The banks were at that 
 time covered with the wild cherries which gave the tributary 
 stream its name. As soon as camp had been established, they 
 went to the places where Russell and his friends had found gold 
 in 1849. Sufficient was found to encourage them. Prospect- 
 ing parties were then organized. One of these went northward 
 until they came to a mountain stream full of large boulders. 
 They went up to the forks of Boulder creek. In a small basin 
 on the left hand branch they found gold, and called the spot 
 Gold run. Another party went across the intervening ridges 
 to Fall river, and over into Spring gulch. They did not de- 
 scend into the valley of North Clear creek at that time, but 
 crossed Quartz hill and found rich gravel at Russell gulch, 
 named after the discoverer, Green Russell. It was too near 
 winter to begin serious mining. They returned to camp. Six 
 
THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 3 
 
 of the party went east to procure provisions, returning in the 
 spring of the following year, 1859. 
 
 This was the year of golden discovery, By the close of 1858 
 rumors of rich diggings had crossed the plains, the rush had 
 set in and crowds began to arrive. Among these came John 
 Hamilton Gregory, who, with J. M. Cotton and his brother, 
 William Cotton, went up Clear creek and discovered the out- 
 crop of the Gregory lode on the 6th of May, 1859. This date 
 is the birthday of Colorado's mining industry. 
 
 The discovery of the Gregory lode was immediately followed 
 by that of other veins, whose production in the succeeding years 
 made Gilpin county the leading gold mining district of the Rocky 
 mountains. 
 
 In the meantime, bands of prospectors had scattered all 
 over the neighboring hills, and were finding the gold de- 
 positories whose later developments made the counties of Clear 
 Creek, Boulder, Gilpin, Summit, Park and Lake one great 
 mining region. 
 
 Boulder was contemporaneous with Gilpin. In 1860 and 
 1861 the Columbia, Ni Wot, Horsfal and Hoosier veins were 
 discovered and brought the Ward district into prominence. A 
 dozen years later the tellurides of Gold hill were first recog- 
 nized in the ores of the Red Cloud mine. The recognition of 
 their true character led to the successful exploitation of the rich 
 ore-bodies of the Magnolia, Melvina, Slide and John Jay mines, 
 and to the growth of the hamlets of Sunshine, Salina, Provi- 
 dence and Magnolia. The Caribou district was born when 
 Samuel Conger found the outcrop of the Poorman lode in the 
 last days of 1869. The development of the Caribou vein began 
 in the succeeding year. 
 
 The pioneers who followed up North Clear creek (or North 
 Vasquez, as it was then called) and founded Gilpin's industry 
 also wandered up the north fork of the stream and discovered 
 the veins whose development gave wealth to Clear Creek 
 county. In August, 1858, George Jackson did some prospect- 
 ing .about Vasquez forks, and in the winter of that year he 
 penetrated to Idaho Springs and went up Chicago creek. On 
 the 7th of January, 1859, he found rich gravel. This led to 
 active search and successful work amid all the other tributaries 
 of Clear creek. The diggers followed the stream to its head- 
 
4 THE DEVELOPMENT OF COLOKADO'S MINING INDUSTRY. 
 
 waters amid the snows of the main range, and discovered the 
 veins above Silver Plume and Georgetown. The sluicing of 
 the soft outcrops of certain veins served as a link leading from 
 placer to lode mining. The Whale above Idaho Springs was 
 one of the finest so worked in 1861. In the upper country, near 
 Empire, the gossan of the Griffith vein was successfully sluiced 
 in 1859. The silver-ores were also recognized about that time, 
 the Running lode, in Gilpin county, having attracted attention 
 to the white metal because of the yield of a peculiar bullion 
 rendered intelligible only when the presence of silver had been 
 determined. The silver-mining industry of Upper Clear creek 
 grew to important dimensions in the decade succeeding 1870. 
 The Pelican and Dives on Republican mountain were discov- 
 ered in 1868, but did not commence active production until 
 1871. The Pay Rock was found in 1872. The mines of Sher- 
 man mountain the Terrible, Dunderberg, Cory City, etc. 
 began to be energetically worked early in the seventies; in 
 Lower Clear creek, John Dumont began operating the Hukill 
 in 1871. In 1878 the Hukill and Freeland were purchased by 
 J. B. Mackay and associates. 
 
 The mines at the head of Virginia canon woke to life by the 
 opening up of the Specie Payment in 1876. 
 
 In the summer of 1859 a party of gold-seekers followed the 
 Platte from the foot-hills through its gateway into the South 
 Park, and, camping on the future site of Fairplay, they crossed 
 over to the western slope and descended the head-waters of the 
 Blue river. Near the place now covered by the town of Breck- 
 enridge, Reuben Spalding sunk the first hole that disclosed the 
 riches of the placers of the Blue. In the following year the 
 gravels of its tributary, the Swan, were prospected. Alma and 
 Fairplay, on the eastern slope, sprang into life as the result of 
 the alluvial mining which then began a productive existence. 
 It was not until 1880, however, after the exhaustion of the first- 
 found shallow gold-bearing gravel, that the veins of Summit 
 county were exploited. The placers of the Blue river and its 
 tributaries have yielded about $35,000,000. 
 
 So were born the mines of Clear Creek, Boulder, Summit 
 and Park counties. But more wonderful discoveries were in 
 store. Leadville was yet to be uncovered. 
 
 Among the scattering bands of placer diggers who spread 
 
THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 5 
 
 over the ranges in 1859, one party followed the Arkansas and 
 camped 011 Georgia bar. In the following spring they con- 
 tinued up the river and divided at the junction of California 
 gulch and the valley of the Arkansas. In a little valley lead- 
 ing from Iowa gulch they stopped at noon. In breaking 
 through the snow to get water for their coffee, the creek had been 
 reached, and in the sand John O'Farrell found some gold. The 
 pieces of porphyry amid the gravel reminded the discoverer of 
 similar conditions observed on the Feather river in California. 
 Little did he guess the significance of those porphyry fragments, 
 or the enormous wealth which that rock covered on the neigh- 
 boring hills. This was April 6, 1860. George Stevens and 
 party came soon after. Their discovery claims were just above 
 the site of the A. Y. and Minnie mines. Then sprang up a 
 placer-mining industry which lasted for fifteen years, and was 
 only obscured by the greater discoveries which ushered in an 
 era of prolific silver mining. 
 
 In the early sixties good gold veins were found on, Printer 
 Boy hill overlooking California gulch. These mines, of which 
 the Printer Boy, Five-Twenty and Pilot were the chief, were 
 productive for several years and foreshadowed the development 
 thirty years later of the gold region rendered distinguished 
 by the yield of the now celebrated Little Johnny property. 
 
 In 1874 W. H. Stevens and A. B. Wood came over the range 
 from Fairplay, where they were mining, to build the ore-ditch. 
 When examining California gulch, Wood found float consist- 
 ing of carbonate of lead ore, and began digging on the south 
 side, now known as Dome hill, on what was afterward the Rock 
 claim. He sank a little shaft through the drift, which covered 
 the outcrop, at a point subsequently worked by an open cut. 
 He found ore in place, but low grade. This was in the fall of 
 1875. He made arrangements to have some work done that 
 winter, and this led to the uncovering of the outcrop across 
 California gulch up Iron hill. The next year the whole line of 
 outcrop-claims was located on the supposed veins, and ore was 
 taken in 1877 from the Rock claim to the smelter at Malta, 
 which had been erected three years before to treat the ores of 
 the Homestake mine.* Stevens got Harrison to erect reduction 
 works in 1877, and in the following year Mr. James B. Grant 
 
 * Situated on the Saquache range opposite Leadville. 
 
6 THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 
 
 put up the establishment from which in later years grew the 
 magnificent metallurgical industry of the Omaha & Grant Smelt- 
 ing and Refining Company. 
 
 In 1878, also, George Fryer sunk a hole on a hill north of 
 Stray Horse gulch, and found carbonate ore, uncovering in this 
 act the great ore-measure which, as " the first contact " proved, 
 was one of the most remarkable bodies of ore known in mining 
 geology. A month later Eische and Hook happened to sink a 
 hole where the contact approached the surface, and found the 
 ore-body which subsequently became the Little Pittsburgh 
 mine, and the foundation of Tabor's fortune. Other discove- 
 ries followed fast, That year 1878 Leadville's output ex- 
 ceeded in value 3,000,000. In 1887 it culminated in an output 
 estimated to be worth $13,500,000. Up to date its yield has 
 been $215,000,000. 
 
 In the meantime other mining camps were being born. In 
 the fall of 1872 veins were found near Rosita, in Custer county, 
 and in 1877 the Bassick began to produce, creating the excite- 
 ment of Silver cliff. 
 
 Among the progeny of the Leadville boom were Kokomo and 
 Robinson, in the Ten-Mile district, whose checkered career be- 
 longs to later days. 
 
 In the meantime the mining industry of Colorado was going 
 through the troubles of its early youth. The history of Gilpin 
 county is so typical of this phase of its development, that I have 
 reserved it for special description. 
 
 Following upon Gregory's discovery, other veins, subse- 
 quently famous, were found. On the 15th of May, the Bates 
 lode was uncovered, on the 25th the Gunnell, Kansas and Bor- 
 roughs. The Bobtail was discovered in June. The early min- 
 ing operations consisted of the removal of the soft decomposed 
 croppings which were washed in the sluices after the fashion of 
 ordinary placer mining. The harder outcrops were crushed 
 under trip-hammers until arrastras were introduced, to give 
 way in their turn to primitive stamp-mills. By the 1st of July, 
 1860, there were 60 mills in operation. Everything proceeded 
 serenely. But the gossan gave way to pyritic ore as the dis- 
 covery shafts penetrated deeper. The saving of the gold became 
 more difficult. In spite of these drawbacks, the richness of the 
 upper portions of the first-found lodes was such as to leave a 
 
THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 7 
 
 handsome margin and maintain a steadily growing population. 
 In the winter of 1863, and the spring of 1864, several mines 
 were sold in New York and Boston. A stock mania super- 
 vened, only to collapse suddenly in April. At this time also 
 came the period of incoherent processes, with the promise of 
 100 per cent, extraction. Some of their progeny still survived, 
 uttering claims nearly as magnificent. The inexperienced, 
 chemist, with his revelation for cheap ore-reduction, continued 
 what the stock-jobber had begun. The mining industry of Gil- 
 pin was crippled unto death. 
 
 At this time the easily amalgamated surface-ores had in many 
 instances become exhausted, giving place to hard pyritic mate- 
 rial, which refused to yield up its contained gold. Extraction 
 in the stamp-mills continued to become worse. Many mines 
 were compelled to close down, others were operated at a ruin- 
 ous loss of the gold in their ores. A depression fell upon the 
 district, which was not removed until 1868, when a general re- 
 vival began. The leasing of claims by working miners led to 
 new discoveries, and the consolidation of adjoining territory 
 diminished expenses. At this time the smelter came to the 
 rescue of the baffled mill-man. In 1867 the Boston and Colo- 
 rado Smelting Company was organized by Professor ~N. P. Hill. 
 In June the first experimental plant was erected at Black Hawk. 
 In January, 1868, the establishment opened for business. In 
 1873 the company ceased the shipment of matter to Swansea, 
 and erected a refinery under the direction of Mr. Richard Pearce. 
 In 1870 the smelter moved to Denver. 
 
 This represents a stage of progress common to all our mining 
 regions. Crude milling methods gave way to fine reduction 
 processes, and the latter, by their heavy charges, invite the mill- 
 man to improve on his cheaper methods, so that competition is 
 restored. The Black Hawk smelter saved the mining industry 
 of Gilpin county when it was on the verge of utter collapse. 
 And on the restoration of prosperity, the owners of the stamp- 
 mills were enabled to carry on experiments whose expense was 
 met by the sale of ore to the smelter, so enabling them to evolve 
 a method of stamp-milling which was well adapted to the treat- 
 ment of the heavy pyritic ores produced by their mines. In 
 1871 the problem had been solved, and to-day 500 stamps do 
 excellent work with the low-grade ore of the district. 
 
8 THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 
 
 Grilpin county has produced about $68,000,000 to date. 
 
 While these problems were undergoing solution, mining was 
 winning fresh territory southward, amid that great complex of 
 mountains whose waters drain into the San Juan river. A 
 party of pioneers, guided by Jim Baker, crossed the Sangre de 
 Cristo range and reached the head-waters of the Anirnas in 
 1861. In spite of snow-slides and Indians the search for gold 
 and silver was extended over the neighboring ranges. The 
 ratification of the Brunot treaty, in 1873, marked the cession of 
 this part of the territory by the Indians, and removed one of 
 the most serious obstacles to the development of the region. 
 In the meanwhile, mines were being opened up on every side. 
 The Baker party tested the river gravels, and the evidences of 
 their placer-workings still remain in many a secluded valley to 
 tell of their first beginnings. In the spring of 1871 lode-mining 
 may be said to have commenced by the discovery and location 
 of the Little Giant vein, just above the present town of Silver- 
 ton, by Miles T. Johnson. In the following year an arrastra was 
 built, and the gold thus extracted out of the ore was taken for 
 sale to Conejos, the nearest trading station. In 1874 Judge 
 Green, of Cedar Rapids, la., commenced the erection of a smel- 
 ter, the machinery of which came on burro-back from Colorado 
 Springs, where the Denver and Rio Grande railroad had just 
 reached. The ore supply of this smelter came principally from 
 the Aspen, which at that time was the chief mine in the locality. 
 
 In 1875 Mr. J. A. Porter, the metallurgist of Green & Co.'s 
 smelter, introduced the syphon-tap, and in the following year 
 he erected the first water-jacketed furnace built in Colorado. 
 
 The prospectors who made Silverton their headquarters scat- 
 tered up the valley of Mineral creek, and on the watershed 
 separating this tributary of the Animas from the Uncompaghre 
 found the veins which gave fame to Red mountain. In 1879, 
 Charles Newman and Harry Irving located the Carbon Lake 
 claim, and did their annual assessment until 1882, when a dis- 
 covery of copper-ore was made on the adjoining Congress 
 claim and shipments began. 
 
 In August of the same year, Andrew Meldrum, while out 
 hunting, stumbled upon the outcrop of galena which marked 
 the now famous Yankee Girl vein. The American Belle and 
 Guston were discovered shortly afterwards. Five years later 
 
THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 9 
 
 this district became a magnificent producer of very rich copper- 
 ores. In 1894 a smelter was erected at Silverton to treat the 
 product of the region. 
 
 In the meanwhile, Gus Begole had crossed the western range 
 from Silverton, and descending into the valley of the Dolores, 
 located claims which later became the Yellow Jacket and Aztec 
 mines. But the ore was too low in grade and the work soon 
 ceased. 
 
 In 1878 John Glasgow and Sandy Campbell came northward 
 from La Plata City, and began the successful development of 
 the Grand View and Atlantic Cable, causing the growth of the 
 town of Rico. The news was spread abroad that another Lead- 
 ville had been found, and crowds trooped in across the hills dur- 
 ing the summer of 1879. In the fall of 1880 the smelter began 
 operations. Nevertheless the district would have gained but 
 slight distinction, had not the ore-deposits of Newman hill been 
 found. These began to be productive when, on the 6th of Oc- 
 tober, 1887, David Swickheimer struck the big ore-body of the 
 Enterprise mine. 
 
 In June, 1870, gold was found in Wightman's gulch. This 
 led to the location of the Little Annie in September, 1873, and 
 the opening up of the Summitville district, which is tributary 
 to Del Norte, whose position made it a natural gateway to the 
 watershed of the Rio Grande. 
 
 Among the old districts recently revived is the La Plata 
 mountain region, north of Durango and south of Rico. In 
 1873, Captain John Moss, representing Tiburcio Parrott and 
 other San Francisco capitalists, came up the San Juan river 
 from Arizona and penetrated the La Plata mountains, being 
 attracted thither by the gold-bearing gravel of the streams. He 
 followed the latter to their source and discovered a large num- 
 ber of veins. The Comstock, Morovitz, Euclid and Ashland 
 claims were located at that time. La Plata City was founded, 
 and great activity characterized the camp for a brief period. 
 But the complex telluride ores proved refractory; and the 
 arrastra was found to be powerless to extract the values. Great 
 expectations had a sequel of small accomplishment. The dis- 
 trict became depopulated. In 1894 new discoveries were made, 
 and a revival took place, leading to more serious work, which 
 now promises better things. 
 
10 THE DEVELOPMENT OF COLORADO^ MINING INDUSTRY. 
 
 And so we come to recent times, no less stirring than the old. 
 The history of the last decade centers round the discovery of 
 Aspen, the stories of Creede and of Cripple Creek, the collapse 
 of silver mining and the development of new gold-fields. 
 
 The first discovery in the Roaring Fork district, of which 
 Aspen is the center, was made July 3, 1879, when Phillip 
 W. Pratt and Smith Steel, coming from Gothic by the Ma- 
 roon pass, found the Galena mine on West Aspen mountain. 
 On the following day they located the Spar claim on Aspen 
 mountain, and on the 5th Messrs. Allbright and Fuller located, 
 at the foot of Smuggler mountain, the Little Rock claim, cover- 
 ing a part of the property of the present Smuggler mine. The 
 Smuggler claim itself was located August 30th, by Charles Ben- 
 nett. On account of the theft of the first four pages of the 
 district recorder's book, it became necessary to make reloca- 
 tions, which now appear on the records at Gunnison, the dis- 
 trict being then a part of Gunnison county. 
 
 The first mineral survey was made on the Monarch mine, 
 October 12, 1879, by John Christian, of Leadville. The site 
 of the present city of Aspen was devastated, in September of 
 that year, by a forest-fire, in which many horses and pack-mules 
 were lost. An Indian scare, following the Meeker massacre, 
 caused most of the prospectors to leave the camp ; but a suffi- 
 cient number remained to build log-cabins on the site now oc- 
 cupied by Aspen, which was located as a placer-claim Septem- 
 ber 20, 1879, by Walter Clark. 
 
 It was not until ten years later that the new district won a 
 commanding position. At that time (1889) the Aspen, Aspen 
 Compromise and Compromise mines maintained a large out- 
 put, and it was in 1891 that the big bonanza of the Mollie Gib- 
 son was uncovered. Aspen is credited with a production of 
 8,275,000 ounces of silver in the year 1892. 
 
 !N". C. Creede found the float of the Holy Moses vein, on West 
 Willow creek, a tributary of the Rio Grande, in 1889. As a 
 consequence, the King Solomon district, as it was then called, 
 began to attract the prospectors scattered in the mountains 
 above Del Norte. No important results ensued until in June, 
 1891, D. H. Moffat and Capt. L. E. Campbell came to Wagon 
 Wheel gap to visit the Holy Moses, on which they had secured 
 an option. Creede was engaged to prospect for them. Shortly 
 
THE DEVELOPMENT OF COLORADO^ MINING INDUSTRY. 11 
 
 afterwards, Theodore Renniger found rich float on Bachelor 
 mountain. He was unsuccessful in finding the vein in place until 
 Creede came along, and, at a point 200 feet higher up on the 
 hill-slope, discovered the outcrop of a large lode. He located 
 the Amethyst claim and then informed Renniger, who took up 
 on the same vein another claim, which he called the Last 
 Chance. This was on the 8th of August, 1891. It should be 
 added that, three years previously, J. C. McKenzie had located 
 several claims on a heavy quartz outcrop, about 150 feet above 
 the Amethyst. These were afterwards abandoned until the 
 fall of 1891, when the Del Monte location covered them. Debris 
 from the upper portions of the mountain had so obscured the 
 outcrop of the Amethyst that its earlier recognition had been 
 prevented. After Creede's discovery but little work was re- 
 quired to prove the existence of a magnificent lode, and, as a 
 consequence, the camp sprang into tremendous activity, cul- 
 minating in the boom of 1892. The immediate extension of 
 the railway from Wagon Wheel gap stimulated a production 
 which reached its maximum in an output of $3,100,000. Then 
 in the summer of 1893 came the sudden fall in silver and a 
 collapse from which Creede has not yet recovered. 
 
 Creede and Cripple Creek were rivals in attracting attention 
 in 1891. Both have had strange vicissitudes. Our new gold- 
 field lies on the southern slope of Pike's Peak, whose snow-clad 
 crest was the beckoning guide of the pioneers of 1858. Al- 
 though no gold discoveries of any moment were made in the 
 early days among the streams, or on the hills lying at the foot 
 of the old beacon mountain, it nevertheless gave its name to the 
 mining excitement of that period. Time has, however, of late, 
 justified the expectations of the tenderfeet of forty years ago. 
 
 The first recorded locations were made in February, 1891, 
 but the clustering hills which are now dotted with productive 
 mines, had been disturbed by the miner's pick as early as 1874. 
 Silver-ores were found in a shaft located close to the present 
 Elkton mine. Ores, rich in the white metal, had been found in 
 late years, and the Moose made one shipment of 30 tons, carry- 
 ing an average of 70 ounces of silver, in addition to the gold. 
 
 Ten years afterward, in April, 1894, the district was the 
 scene of the queer fiasco which has gone into local history as 
 the Mt. Pis^ah excitement. A crowd of 4000 men were 
 
12 THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 
 
 brought together on the rumored discovery of rich placer 
 ground. Nothing was found save in the holes of the original 
 locators. Man had endeavored to remedy nature's niggardli- 
 ness and the poor rock had been artificially enriched. Lynch- 
 ing was threatened, but in the failure to catch the perpetrator 
 a big picnic took place, after which the hill slopes again became 
 the quiet cattle ranges for which they seemed best adapted. 
 Those deluded prospectors let slip a great opportunity. Mt. 
 Pisgah's dark front now overshadows the busy streets of the 
 town of Cripple Creek, and, on the ridges opposite, line after 
 line of smoking chimneys bespeak a long succession of pro- 
 ductive mines. 
 
 During the spring of 1891 Cripple Creek began to receive 
 respectful mention in mining circles, but the discoveries made 
 at Creede during that summer diverted attention from a dis- 
 trict whose previous experience had given it an unsavory repu- 
 tation. When, however, the silver market collapsed in June, 
 1893, and mining seemed prostrated, the men of Aspen and 
 Leadville turned with the energy of despair to the new gold 
 field which previously had been pooh-poohed, and the concen- 
 trated activities of the State were directed to the development 
 of Cripple Creek. With a rare good fortune, the new camp 
 answered to the call, and, as explorations extended, there came 
 a swift succession of rich discoveries which caused the output 
 to spring from $583,000 in 1892 to $2,100,000 in 1893. This 
 growth continued so that in 1894 the yield was $3,900,000, and 
 in 1895 it reached $7,800,000. These figures are sufficiently 
 eloquent of the development of a district which to-day is the 
 largest producer of all the gold-mining camps of the United 
 States. 
 
 During the past three years discoveries in other parts of the 
 State have received mention, and large claims have been made 
 in behalf of several new districts. West Creek, Cottonwood, 
 Hahn's Peak and the Gunnison region may be cited. Of these 
 the last named is much the most important. At the head-waters 
 of certain streams, tributary to the Gunnison river, there have 
 been found veins which are now supplying several stamp mills 
 with pay-ore, and have given birth to the settlements of Vulcan, 
 Spencer, Iris and Dubois. 
 
 While the new territory which has been won during later 
 
THE DEVELOPMENT OF COLORADO'S MINING INDUSTRY. 13 
 
 days adds its tribute of gold and silver to the yield of the old 
 established mining centers, it must be noted that the latter have 
 also accommodated themselves to new economic conditions. 
 The Silverton district, in the southwest, for instance, which in 
 1892 yielded gold worth $155,624, and silver valued at $354,- 
 125, gave in 1894 gold amounting to $360,320, and silver worth 
 $235,000. This is typical of the changed conditions regulating 
 the industry. It is a striking evidence of that resourcefulness 
 which has enabled the State to overcome difficulties. The col- 
 lapse of the silver-mining led directly to an impetus in the 
 search for gold, and the variety of ores so puzzling in the in- 
 fancy of our smelting industry, is to-day its chief aid, because 
 it enables the attainment of that admixture of material which 
 is the essential of successful reduction. 
 
 Colorado has yielded to date gold valued at $137,475,000, 
 and silver having a coinage-value of nearly $400,000,000. 
 
 Thus, from humble beginnings, a great and complicated in- 
 dustry has been created. Its development may be summarized 
 in four periods : The discoveries in Gilpin county and the ad- 
 joining camps in the granite 'rocks of the front range, the era 
 of silver-mining in the carboniferous limestones of Leadville, 
 Aspen and Rico, the development of the fissure veins in the 
 andesites of the San Juan, and lastly, the revival of gold-min- 
 ing consequent upon the uncovering of a great series of ore- 
 deposits in the volcanic complex of the Pike's Peak region. 
 
SUBJECT TO REVISION. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 Gold-Milling in the Black Hills, South Dakota, and at 
 Grass Valley, California. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Atlanta Meeting, October, 1895.) 
 
 OUR Transactions contain two notable papers descriptive of 
 the stamp-milling practice of the Black Hills and of Grass 
 Valley, namely, the elaborate and complete treatise of Prof. H. 
 O. Hofman, on Gold-Milling in the Black Hills,"* and the 
 paper describing the North Star mill, by E. R. Abadie, its 
 superintendent. f Having visited and examined the stamp- 
 mills of both localities, I venture to offer here such comment 
 as more recent information or a different point of view has 
 suggested. | 
 
 I. THE BLACK HILLS. 
 
 Prof. Hofman's paper was prepared in 1888, seven years ago, 
 yet the methods in vogue to-day at Lead City and Terraville 
 do not differ materially from those so carefully described by 
 him. 
 
 The mining industry of the Black Hills is not so actively 
 prosperous in 1895 as it was in 1888. Not so many stamps are 
 dropping ; some of the mines have been compelled to suspend 
 operations owing to a falling off" in the yield of ore, while others 
 have passed into the comprehensive control of the Homestake 
 management. Nevertheless, the mines and mills of the Belt 
 produce more gold than any other single mining camp in the 
 United States, with the exception of Cripple Creek, Colorado. 
 
 * Trans., xvii., 498. f Id., xxiv , 208. 
 
 1 For more detailed descriptions and discussions, I would refer to a series of 
 papers on "Variations in the Milling of Gold-Ores," which I have contributed to 
 the Engineering and Mining Journal during the present year, and from which quo- 
 tations are made, and statistical material is reproduced in the present paper. The 
 illustrations herewith given will be found, with others, in the Journal of Septem- 
 ber 7 and 14, 1895, and are here used through the courtesy of the Scientific Pub- 
 lishing Company. 
 
Z GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 The Belt is that part of the region contiguous to the Home- 
 stake lode and its extensions, and reaching from Whitewood 
 creek to Dead wood gulch. It is the center of the mining ac- 
 tivity of the Black Hills, the only important mining region in 
 the State of South Dakota. 
 
 The geological relations of the ores of the district have been 
 referred to in our Transactions by W. B. Devereux* and F. B. 
 Carpenter, respectively, f It is to be regretted that so important 
 and interesting an ore-deposit as the Homestake vein should 
 not have undergone long ago more detailed description at the 
 hands of some one of our members. The commercial environ- 
 ment of mining enterprises often militates against scientific in- 
 vestigation. 
 
 While the writer has not had an opportunity of making a 
 careful examination of the mines, a visit underground was 
 sufficient to show the justification for the great ore-reduction 
 establishments of the Homestake Mining Co. The ore occurs 
 in large bodies of quartzified chloritic schists, conforming to 
 the structure of the country and being a portion of it. The 
 width of milling-ore varies from 50 to 400 feet. Most of the 
 supply comes at present from above the 500-foot level ; but the 
 developments in lower levels, down to the 800-foot, indicate the 
 continuity of the enormous ore-shoots of the mine. The huge 
 excavations made along the outcrop of the lode (See Fig. 1), 
 are a distinctive feature of the present topography of the Belt, 
 and bear impressive witness to the immense quantities of mill- 
 stuff that have gone under the stamps. Extensive bodies of ore 
 are still held in reserve in these surface open-cuts. 
 
 Behind the Highland shaft-house there is a large cut, which 
 gives a very excellent section of the geological formation, 
 showing the uptilted edges of the gold-bearing schists, overlain 
 by Cambrian sandstone. The latter, only a few feet thick at 
 this point, is split by an intruding sheet of the porphyry which 
 also overlies the whole formation and caps the hilltop. The 
 lowermost member of the Cambrian series is a conglomerate, 
 identified by its fossils as belonging to the Potsdam period, and 
 said | to have been derived from the degradation of the gold- 
 
 * Trans., x. 465. f Id., xvii., 570. 
 
 % By Devereux, Trans., x., 966, et seq. The development of the conglomerates 
 of the Witwatersrand adds much interest to these Dakota deposits. 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 3 
 
 bearing lode under the outcrop of which it was formed by the 
 seas of a very early geological time. These facts indicate for 
 the Homestake vein an origin of remarkable geological an- 
 tiquity. 
 
 The porphyry above mentioned is a felsite. At one time it 
 was broken with the ore and sent to the mills in spite of its 
 valueless character. Kow it is used for filling up stopes. Un- 
 derground it can be seen in dikes conformable to the vein- 
 walls, and splitting the ore-bodies by its intrusion. 
 
 The first mill in the Black Hills was that erected by the 
 Racine company, at the lower end of Lead City, in April, 1877. 
 The beginning of the mining industry of the Black Hills dates 
 back to June, 1876, when the Wheeler brothers found rich 
 gravel in Deadwood gulch. The outcrops of the large quartz- 
 lodes were early seen, but quickly discarded by the California 
 and Montana miners, who ridiculed the idea of the profitable 
 handling of ores which yielded on panning only from three to 
 ten dollars per ton. 
 
 After the placer-mines had commenced to yield handsomely, 
 and while the quartz-lodes were unappreciated, the early min- 
 ing activity was diverted to the development of the lowermost 
 beds of the Potsdam formation, the gold of which lay in a 
 conglomerate. It was to reduce this conglomerate that the 
 first stamp-mills were introduced. They were of the primitive 
 Colorado pattern, and proved entirely unsuited to the extraction 
 of gold from such material. They made a poor record, and 
 were followed by the fast-dropping stamps, modeled on Califor- 
 nian practice, first introduced by Mr. Augustus J. Bowie, Jr., 
 in his design of the Father de Smet mill,* the erection of 
 which, at Terraville, was commenced in June, 1878. This 
 plant was succeeded by the first of the Homestake Co.'s mills, 
 which also had a narrow mortar and a rapid discharge. The 
 Caledonia, erected the following year, used more roomy mortars 
 and two inside amalgamating-places, more after the Colorado 
 fashion. This mill is now idle, chiefly for lack of suitable 
 ore-supply, and therefore a comparison between the two styles 
 of working is not possible. ISTevertheless, I do not hesitate to 
 say that the Homestake mortar, deep and narrow, gives a com- 
 
 *See Trans.,*., 87. 
 
4 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 bination for rapid pulverization and high percentage of extrac- 
 tion inside the battery which render it, for the ores of this 
 district, far superior to any other mortar I know. 
 
 All the mills now at work on the Belt are under the direc- 
 tion of the Homestake management, with the exception of the 
 little 10-stamp Columbus mill at Central City. When Prof. 
 Hofman wrote his paper, there were 660 stamps dropping on 
 the free-milling ores of the Belt; to-day the number is 550. 
 The Be Smet and Caledonia mines have been unable to sur- 
 vive a diminution in the tenor of the ores they produced, and 
 the mills belonging to them have ceased operations, the former 
 in 1892 and the latter in 1893. The Highland Co.'s mill has 
 been lately increased by the addition of 20 stamps. The Golden 
 Terra and Deadwood mills were consolidated six years ago, the 
 80 stamps of the Terra being placed behind the 80 stamps of 
 the old Deadwood mill. The two large mills of the Home- 
 stake Co. have undergone steady enlargement, and in addition 
 to the number of stamps given in the annexed table, there are 
 40 about to be added to the Golden Star mill, whose total will 
 then be 200 stamps. 
 
 TABLE L The Stamp Mills of the. Belt, South Dakota. 
 
 Name. 
 
 d 
 
 cW 
 P 
 
 Location. 
 
 Number of 
 Stamps. 
 
 Owners. 
 
 Homestake 
 
 1878 
 1879 
 1880 
 1879 
 1880 
 1878 
 1879 
 1894 
 
 Lead City. 
 Lead City. 
 Lead City. 
 Terraville. 
 Terraville. 
 Central City. 
 Terraville. 
 Central City. 
 
 1888. 
 
 801 
 
 120 / 
 120 
 801 
 80 j 
 
 100 
 
 80 
 
 1895. 
 100 \ 
 160 / 
 140 
 
 160 } 
 
 100 
 
 80 
 10 
 
 The Homestake Mining 
 Co. 
 The Highland Mining Co. 
 The Deadwood - Terra 
 Mining Co. 
 The F. de S. Mining Co. 
 The Caledonia Min. Co. 
 
 Golden Star 
 Highland 
 
 Deadwood 
 
 Golden Terra 
 Father de Smet. 
 Caledonia 
 
 Columbus 
 
 
 
 The ore is dumped at the shaft's mouth into the rock- 
 breakers. At the time of Prof. Hofman's investigations, all 
 the Homestake mills were using the Blake, and the Caledonia 
 had just introduced a Gates crusher. Since that? time the 
 Gates has replaced the Blake rock-breaker in every mill on the 
 Belt. Furthermore, the rock-breaker is now placed in the 
 shaft house instead of at the mill. This follows the teiiden- 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 5 
 
 cies of modern practice in California, where the crusher at the 
 mine delivers the broken ore to the tramway, which carries it 
 to the mill, or sometimes to a second rock-breaker. The latter 
 arrangement relieves the stamps of the hard work of stone 
 breaking, facilitates pulverization in the mortar and gives uni- 
 form conditions more favorable to successful amalgamation. 
 
 The transference of the rock-breaker from the mill to the 
 mine is in itself a praiseworthy change. It enlarges the 
 capacity of the ore-bins at the mill, and renders unnecessary 
 the use of separate bins for coarse and fine. In small plants 
 where the breaker, if at the mill, would not be driven by a 
 separate engine, it does away with that irregularity in the work- 
 ing of the mill arising from the unequal consumption of power 
 on the part of a rock-breaker. It renders easy the loading of 
 the cars which bring the ore from the mine, a factor important 
 in the case of aerial rope-ways carrying buckets of small 
 capacity. But more important than these minor advantages is 
 the almost entire cessation of the production of the dust so in- 
 jurious to all the mechanism of the mill and always such a 
 nuisance to those who work in it. 
 
 Most of the mills use the No. 6 Gates breaker. The Dead- 
 wood-Terra and Highland have two each. The Homestake 
 mine has three, one of which is held in reserve to avoid delay 
 due to repairs on either of the others. Experience has shown 
 that the larger receiving capacity of the Gates and its greater 
 crushing power render it more suitable for large milling-estab- 
 lishments than the Blake. 
 
 Prof. Hofman has described the various methods for trans- 
 mitting the power to the different parts of the mill. Of these, 
 the arrangement in the Golden Star mill resembles that in 
 vogue in California and in the best Colorado mills. The driv- 
 ing-shaft is approximately level with the cam-shaft, and the 
 connecting-belts are nearly horizontal. The latter are in a 
 place easily accessible, well lighted and away from the dirt and 
 water inseparable from the close neighborhood of the battery 
 itself. Such an arrangement requires that the sills under the 
 cam-floor shall be made stronger than if they simply supported 
 the flooring, but the additional expense is trifling compared to 
 the convenience of the plan. On the other hand, the placing 
 of the counter-shaft immediately underneath the feeder-floor, 
 
6 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 an addition to the inaccessibility and inconvenience, the environ- 
 ment of dirt and water, the absence of light, etc., requires the 
 use of tighteners injurious to the belting. The Star mill uses 
 one belt while the Highland wears out three. 
 
 All the batteries are placed upon flat sites in two rows back 
 to back, save at the Father de Smet, where the two rows of 
 batteries face each other and discharge toward the center of the 
 mill. The latter arrangement gives a larger storage-capacity to 
 the bins overhead, but this advantage is obtained at the greater 
 cost of darkening the amalgamating-tables. 
 
 The mortar is the most interesting feature of the Homestake 
 mills. In Prof. Hofman's paper there are drawings of it, one 
 of which is reproduced here in Fig. 2. Fig. 3, from a photo- 
 graph furnished by Fraser and Chalmers, illustrates the latest 
 design. The changes in the dimensions made since 1888, the 
 date of Prof. Hofman's paper, are as follows : 
 
 1888. 1895. 
 
 Weight, . . .. . ; . . 5400 pounds. 7800 pounds. 
 
 Length of base, .... 54| inches. 56| inches. 
 
 Width " " . . . 27J- " 28} " 
 
 Height, . ; . .. - ., ,' . 54 " 58} " 
 
 Inside width at the level of the lip, 13J " 12 J " 
 
 The most important change is the narrowing of the interior 
 width at the level of the lip of the mortar, w^here a slight 
 change is more important than in any other dimension. The 
 measurement of a new mortar lying outside the Golden Star 
 mill gave an inside width of 13 inches. At the Columbus mill 
 it is 12 inches. The mortar, as now made, is provided with 
 cast-steel false bottoms 2J inches thick, with a cast-iron lining 
 | inch thick along the sides and J inch thick upon the feed- 
 hopper. The inside copper plates, placed along the front, are 
 J inch .thick and are attached to chuck-blocks. The latter are 
 wooden blocks, designed so as to serve as a false lip to the 
 mortar, thereby raising the depth of the issue. A piece of 2- 
 inch plank is bolted to a If-inch board, the latter being made 
 to project about 2 inches beyond the former, to which the cop- 
 per plate is attached. The 2-inch plank had been replaced, at 
 the time of Prof. Hofman's inspection, with J-inch iron, but 
 has since been reverted to, because the slight increase in the 
 distance between the chuck-block and the shoe obtained by the 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 7 
 
 arrangement he describes was undesirable in a mortar charac- 
 teristically narrow and designed for rapid crushing. 
 
 Two of these chuck-blocks are in use, one 9 and the other 7 
 inches high. When new dies have been introduced, the former 
 is inserted, then making the distance from the bottom of the 
 screen to the top of the die about 9 inches. As the dies wear 
 down, the depth of discharge increases until, after about a 
 fortnight, it becomes necessary to replace the high chuck-block 
 with the lower one. The difference of 2 inches between the 
 two is approximately equal to the diminution in the thickness 
 of the die. After a further service of two or three weeks the 
 dies are worn out, the depth of discharge has increased to 11 
 inches, new dies are inserted, and the high chuck-block is re- 
 introduced. In this way some sort of an effort is made to 
 maintain a rough uniformity in the depth of the issue, a factor 
 the importance of which is generally overlooked or underesti- 
 mated in stamp-milling. 
 
 It may be added that the copper plate on the high chuck- 
 block is flat, while on the other it has a curved surface, and is 
 mounted on slightly thicker wood, so as to bring it nearer the 
 die. It is the intention of the mill-man to keep the bottom of 
 the chuck-block about on a level with the bottom of the shoe, 
 and to avoid so close a neighborhood to the ore on the die as 
 would lead to the scouring of the amalgamated surface of the 
 copper plate. 
 
 There is only one inside plate, made of plain copper and 5 
 inches wide. This is the one attached to the chuck-block. 
 There is no back-plate, as was the case in the Caledonia mill 
 (now idle), where the mortar was more roomy and of a dif- 
 ferent design. Free mercury is fed at intervals into the bat- 
 tery with the ore. 
 
 The Homestake mortar combines, to a notable degree, the 
 two excellent features of a rapid discharge and a high percent- 
 age of amalgamation. Its width at the issue used to be 13J, 
 was then diminished to 13, and in the newest design is 12 
 inches. The depth, by the introduction of chuck-blocks, is 
 raised to from 9 to 11 inches. The mortar becomes thereby 
 both narrower and deeper than the Californian pattern, its nar- 
 rowness compelling a rapid expulsion of the pulp and giving 
 the mill a capacity nearly twice that of the average Californian 
 
8 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 battery when working ore of similar character. At the same 
 time the depth of the mortar prevents the scouring of the in- 
 side plate, and permits the arrest of the gold by this plate and 
 by the free mercury added with the ore, so that the percentage 
 of extraction follows closely in the wake of the roomy mortar 
 of the Colorado mill, the crushing capacity of which is only 
 one-quarter that of the Homestake. The following comparison 
 will be of interest : 
 
 TABLE II. Comparison of Typical Mills. 
 
 
 
 . 
 
 
 OT 
 
 
 ^. 
 
 
 
 2? 
 
 P. 
 
 1 
 
 
 p 
 
 
 <u 
 
 A 
 
 1 
 
 fi 
 
 d, 
 
 o.S 
 
 
 1 
 
 X 
 
 \ 
 
 a 
 
 
 
 DO 
 O 
 
 !l 
 
 \ 
 
 Sg 
 
 bj>S| 
 
 
 .c 
 
 
 S 
 
 ^W) 
 
 |l 
 
 I 
 
 1? 
 
 
 S 
 
 Z- 
 
 "S 
 
 
 S 
 
 Z3 O 
 
 - 
 
 
 
 (S 
 
 f 
 
 525 
 
 w 
 
 ^P. 
 
 
 Inches. 
 
 Inches. 
 
 Lbs. 
 
 
 Inches. 
 
 Tons. 
 
 Golden Star, Dead wood, S. Dak 
 
 
 9 to 11 
 
 850 
 
 85 
 
 
 4 
 
 Hidden Treasure, Black Hawk, Col.. 
 
 24 2 
 
 13tol5 
 
 550 
 
 30 
 
 17 ? 
 
 1 
 
 North Star, Grass Valley, Cal 
 
 174 
 
 4 
 
 850 
 
 84 
 
 7 
 
 \\ 
 
 Pearl Bendiffo Australia 
 
 1 Z 
 
 15 
 
 
 840 
 
 74 
 
 71 
 
 
 
 
 
 
 
 * 4 
 
 
 It will be seen how closely the crushing-capacity is related 
 to the interior width of the mortar at the level of the issue. 
 Notwithstanding its rapid crushing, the Homestake mortar re- 
 tains a percentage of the total gold extracted which compares 
 well with any of the other districts, and is superior to some of 
 them, though this factor will be affected by the variety of 
 screen in use. 
 
 In 1888 the Homestake mills were using ~No. 7 diagonal-slot 
 Russia iron punched screens. At the present time the mills 
 uniformly employ the No. 8 size of the same variety. This 
 means slightly finer pulverization. Prof. Hofman gives the 
 crushing-capacity in 1888 at 4J tons per stamp per day, with a 
 9-inch drop 85 times per minute. It is now about 4 tons per 
 day, with a 9J-inch drop and the same speed. This shows the 
 effect of the substitution of the No. 8 for the No. 7 screen. 
 
 The No. 8 screens are considered equivalent to 30-mesh 
 wire. They break before they become worn out because of 
 lines of weakness developed by the press used in their manu- 
 facture. They are, however, never retained in service until the 
 
d 
 
 c 
 
 " 
 
FIG. 2. 
 
 Scale, 1 inch = 1 foot. 
 The Homestake Mortar. 
 
FIG. 3. 
 
 The Homestake Mortar. 
 
i 
 
 m 
 
 
 l * 1 r. 
 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 apertures are much worn, because this would produce a coarse 
 crushing detrimental to a uniform product. Their maximum 
 service is about two weeks, but this is rarely attained, because 
 breakage occurs after six to eight days. The cause of this is 
 the accumulation, inside the battery, of wood chips, which have 
 found their way into the ore from the timbers in the mine. 
 They tend to dam up the pulp within the mortar, and so sub- 
 ject the screen to a pressure greater than it can bear. This re- 
 sults in a break or a burst. Where surface-ore is being milled, 
 as at the Deadwood-Terra, the life of the screen is prolonged 
 to an average of nine or ten days, because such ore comes from 
 workings where there is but little timbering. 
 
 At the neighboring Columbus mill, 30-mesh brass wire is 
 used, and the choking of the screens is minimized by having 
 three sets for each battery, so that while one is in place the 
 second is being dried out and the third cleaned with a wire brush. 
 It would be better if the Homestake mills could find it practi- 
 cable to use wire-cloth instead of punched Russia iron, since, 
 apart from the advantage of a more uniform discharge, the pul- 
 verization is more regular, because the wires do not wear so 
 easily as the punched holes, and the apertures therefore retain 
 their size, and the screen does good work until simple breakage 
 requires that it be patched or discarded. 
 
 The process of gold-extraction consists of amalgamation 
 within the mortar upon outside plates and in traps, supple- 
 mented in a rudimentary way by an inadequate effort to con- 
 centrate the sulphides of the tailings. 
 
 The mortar becomes an amalgamating apparatus by the use 
 of the inside copper plate and the addition of free mercury. 
 About 50 per cent, of the total amalgam is obtained from these 
 inside plates. At the Deadwood-Terra the proportion reaches 
 70 per cent. 
 
 To quote from my previous paper* on the subject : 
 
 ' ' Mercury is fed into the battery in quantities proportioned to the richness of 
 the ore and regulated by the condition of the amalgam on the apron-plates. At 
 the four principal mills the rate at which the mercury is fed can be judged by the 
 accompanying record, coyering the two weeks preyious to my yisit. 
 
 "It will be observed that though the Golden Star and the Deadwood-Terra 
 mills crush approximately the same amount of ore, the former uses more than 
 
 :: Eng. and Mining Journal, p. 222, September 7, 1895. 
 
10 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 twice as much mercury. This fact is explained by the wide difference in the rich- 
 ness of the ore, for while that crushed in the batteries of the Golden Star aver- 
 ages from $4 to $5 per ton, that which goes through the Deadwood-Terra ranges 
 from $1.50 to $2 per ton. 
 
 TABLE III. Consumption of Mercury at the Homestake 
 Stamp-Mills. 
 
 Date. 
 
 Deadwood- 
 Terra. 
 160 Stamps. 
 
 Golden Star. 
 160 Stamps. 
 
 Highland. 
 120 Stamps. 
 
 Homestake. 
 100 Stamps. 
 
 Mayl, 1895 
 
 Lbs. 
 11 
 10 
 10 
 12 
 * 9 
 10 
 11 
 11 
 11 
 10 
 11 
 10 
 
 Ozs. 
 5 
 2 
 
 2 
 12 
 . 6 
 11 
 6 
 8 
 14 
 
 12 
 
 Lbs. 
 25 
 *17 
 25 
 26 
 25 
 24 
 23 
 24 
 23 
 25 
 23 
 24 
 
 Ozs. 
 13 
 14 
 16 
 13 
 3 
 8 
 2 
 12 
 13 
 3 
 7 
 6 
 
 Lbs. 
 15 
 *12 
 15 
 17 
 10 
 16 
 17 
 19 
 19 
 18 
 18 
 17 
 
 Ozs. 
 4 
 9 
 1 
 10 
 6 
 8 
 
 3 
 8 
 12 
 8 
 4 
 
 Lbs. 
 * 9 
 12 
 13 
 12 
 11 
 12 
 12 
 12 
 12 
 12 
 12 
 11 
 
 Ozs. 
 10 
 
 2 
 
 12 
 7 
 2 
 8 
 15 
 13 
 13 
 7 
 1 
 
 2, 
 
 3 
 
 4 
 
 5, 
 
 6, 
 
 7 
 
 g' 
 
 9 
 
 '10 
 
 11 
 
 12 
 
 Average per day 
 
 11 
 
 4 
 
 24 
 
 3 
 
 17 
 
 2 
 
 12 
 
 2 
 
 " For the year ending June 1, 1894, the Homestake mill used 2084 pounds and 
 the Golden Star mill 3440 pounds, making a total of 5524 pounds avoirdupois, 
 which, at the price obtaining that year, 4*2 cents, makes the value of the mercury 
 used $2320.13. During that time 309,210 tons of ore were crushed, so that the 
 consumption was at the rate of about 5 dwts. Troy or | cent per ton. At the 
 DeadwoodrTerra 205 pounds were used in February, 1895, in treating 18,483 
 tons of ore. It is estimated that 22 per cent, of the amount of mercury used 
 is lost." 
 
 On issuing from the battery the pulp falls from 6 to 10 inches 
 before striking the aprons or first amalgamatiiig-tables. This 
 serves no particular purpose, while the actual damage possible 
 to the plates by the scouring of their surface due to the impact 
 of the pulp is obviated by the interposition of a splash-board, 
 which breaks the fall of the sand and water. This splash-board 
 might be placed at such an angle as would permit of its use 
 as an amalgamating device by lining it with a copper plate. 
 
 In the Homestake Co.'s mills the aprons are 10 feet in length 
 and 4J feet wide. Those in the Highland mill are only 8 feet 
 long. In all these mills two apron-plates deliver the pulp to 
 one tail-plate having a size equal to one apron. At the Dead- 
 
 * Indicates clean-up days. 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 11 
 
 wood-Terra the aprons are somewhat larger, namely, 11 feet by 
 4 feet 8 inches, but the tail-plate is 8 feet long and only 16 
 inches wide. The latter is called, very appropriately, a sluice- 
 plate, and is a truly absurd device for arresting the gold. 
 
 In the Homestake mills, both apron- and tail-plate have a 
 slope of 1 J inches per foot, the minimum gradient at which the 
 tables can clear themselves of the pulp. Both tail-plate and 
 apron are dressed each morning, the aprons are cleaned up par- 
 tially each day, and more completely deprived of their amalgam 
 at the bi-monthly general clean-up, when both the tail-plates 
 and the inside mortar plates are gone over. 
 
 The traps are intended to arrest escaping amalgam. The 
 Golden Star mill (jsee Fig. 4) has two at the head of the tail- 
 plate. They are 18 inches deep. They are preceded by a 
 shallow trap or riffle 2 inches deep, which is stated to do better 
 work because of the more regular passage of the pulp. These 
 traps catch about 1 per cent, of the total amalgam. They are, 
 to quote again, 
 
 " Cleaned up every two weeks, the accumulated pyrites are shovelled into buckets 
 and then passed into a pan, which extracts all the free amalgam. The residues 
 from the pan are then fed into a particular 5-stamp battery, provided with a No. 
 :0 slot screen. They are passed through this battery twice and are then sent to 
 the smelter, their final assay value being about $38 per ton. 
 
 "The above suggests the Australian practice of mercury Avells, particularly em- 
 ployed at Chines, with the obvious difference that the Homestake traps are not 
 supplied with free mercury. It is claimed that if sufficient mercury is fed into 
 the battery no free gold should escape, and the mercury in the traps would merely 
 serve to thin the amalgam and make it easier of escape. The traps catch concen- 
 trates and amalgam only." 
 
 Then comes the concentration of the sulphides. Of this, 
 not much can be said. The Deadwood-Terra mill makes no 
 attempt to save the sulphides, since the ore comes from near 
 the surface and contains nothing worthy of supplementary 
 treatment. The Homestake mills and that of the Highland 
 company are using the Gilpin county bumping-table. Seven 
 years ago Prof. Hofman, noting the absence of any effort to 
 save the valuable sulphides, suggested the employment of 
 Spitzhltten, supplemented by Spitzkastev, preparatory to the re- 
 crushing of the coarse sands and the concentration, on buddies, 
 of the fine. This very sensible advice has not been followed. 
 Instead, however, two blanket houses were erected, and, with- 
 out any sizing or classification such as should precede all con- 
 
12 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 centration, the blanketings were worth from $20 to $30, per 
 ton. These have been idle for several years, and in their 
 place eight bumping-tables were placed in both the Highland 
 and Golden Star mills, while six were added to the Homestake 
 mill. It is only necessary to add that the two larger mills have 
 crushing capacities of 560 and 640 tons per day. and the Home- 
 stake about 400 tons, to indicate the absurdly disproportionate 
 nature of the equipment, which can only be considered a badly- 
 designed experiment. The results obtained are not by any 
 means a proof .of what could be done under proper conditions, 
 as already stated in my previous criticism of this feature : 
 
 "During the year ending June 1, 1894, the two Homestake mills produced 
 915,010 pounds of concentrates whose assay value varied from |5 to $8 per ton. 
 They consist of iron pyrite, arsenical pyrite and pyrrhotite. The ore contains 
 from 3 to 5 per cent, of sulphides, but only about 2 per cent, are saved. They 
 are sent by rail to the Deadwood and Delaware Smelter, just below the town of 
 Deadwood, where they are treated at a charge of half their assay value, and con- 
 verted into an iron matte very low in copper and rich in gold, which goes to 
 the Omaha and Grant Smelting and Kefining Company, at Omaha, for further 
 treatment. ' ' 
 
 At the present time experiments are being made with jigs in 
 order to improve this part of the milling. It is to be regretted 
 that a representative company, such as that operating the 
 Homestake mines, should be so slow to adopt the best metal- 
 lurgical practice, remaining satisfied with a manifestly inade- 
 quate equipment and a thoroughly unscientific treatment until 
 the successful work of a Cornishman, treating its mill tail- 
 ings a few miles down the creek, emphasized the desirability of 
 doing something better. 
 
 Prof. Hofman has described in detail the method of sampling 
 the mill-stuff by simple panning. At the present time the mill- 
 work is checked by sampling the pulp as it leaves the apron- 
 plates and fills a dipper at intervals of an hour for a period of five 
 hours. This is done each afternoon. The gold is determined 
 by fire-assay. No accurate knowledge of the completeness of 
 the extraction can be obtained by so unsystematic a procedure. 
 
 The labor-costs are given in the accompanying table : 
 
 By comparing this with Table V. in Prof. Hofinan's paper, it 
 will be noticed that the mills have been enlarged without a pro- 
 portionate increase of workmen. In 1888 the Homestake mill 
 employed 20 J men to attend to 80 stamps and the Golden Star 
 23 J men for its 120 stamps. The chief change is hi crusher- 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 13 
 
 l 
 
 
 o <M : 10 o o o 10 o o o o 
 
 OO -^ CO CO US ^ CO CO CO CO <N 
 
 i-H C <N <M i-l Tt< <M <?} -^ CO 
 
 l 
 
 si 
 
 as 
 
 QQ.C! 
 
 iH rt< (N (M (M <M 
 
 
 i 
 
 Q 
 
 Q 
 
 8 8 
 
 i> co co c4 
 
 o oo ooo 
 
 tO ^5 tO iO ^O ^5 
 CO CO <N C<i C4 O^ 
 
 Name of mi 
 Number of 
 
 SlB j 
 
 II 
 
14 GOLD-MILLING^IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 men, the number of whom, by the substitution of the large Gates 
 for the small Blake rock-breakers, has been diminished from 
 5 and 6 men respectively to 2 for each mill. The Golden Star 
 now employs 4 general laborers in place of 2, and the Home- 
 stake 2 in place of 1, and this is the only increase following the 
 enlargement of the mill. The engine-men, firemen, amalgama- 
 tors, etc., remain the same in number, while the general super- 
 intendence (foreman) has been diminished for any single mill 
 by giving one man charge of both the Homestake mills as well 
 as that of the Highland Co.'s. 
 
 The milling costs, per ton of ore, are as follows : 
 
 TABLE V.Cost of Stamp-Milling in tfie Black Hills, South Dakota. 
 
 A. THE HOMESTAKE MILL. 
 
 Year 
 
 1887-1888. 
 80. 
 
 1888-1889. 
 80. 
 
 1893-1894. 
 80. 
 
 Number of stamps 
 
 
 Tons treated 
 
 96,790 
 
 $0.2561 
 0.0130 
 0.1729 
 0.2766 
 
 106,780 
 
 $0.2395 
 0.0045 
 0.1562 
 0.2230 
 
 104,995 
 
 $0.2543 
 0.0105 
 Orl986 
 0.0597 
 0.1784 
 0.1097 
 0.0034 
 
 Labor 
 
 Supplies 
 
 Water 
 
 Wood 
 
 Coal 
 
 Machinery 
 
 0.0922 
 0.0109 
 0.0016 
 0.0103 
 0.0070 
 
 0.0893 
 0.0084 
 0.0014 
 0.0053 
 0.0139 
 
 Oil 
 
 Candles 
 
 Quicksilver 
 
 0.0083 
 0.0167 
 0.0155 
 
 Lumber 
 
 Timber 
 
 Total cost per ton of ore 
 
 
 
 $0.8406 
 
 $0.7415 
 
 $0.8551 
 
 
 B. THE GOLDEN STAB MILL. 
 
 Year 
 
 1887-1888. 
 120. 
 
 1888-1889. 
 120. 
 
 1893-1894. 
 160. 
 
 Number of stamps 
 
 
 Tons treated 
 
 146,565 
 
 $0.2138 
 0.0079 
 0.1712 
 0.2739 
 
 161,755 
 
 $0.1755 
 0.0044 
 0.1622 
 0.1959 
 
 204,215 , 
 
 $0.1556 
 0.0121 
 0.2043 
 0.0346 
 0.1637 
 0.1057 
 0.0021 
 
 Labor 
 
 Supplies 
 
 Water 
 
 Wood 
 
 Coal 
 
 Machinery 
 
 0.1220 
 0.0084 
 0.0014 
 0.0252 
 0.0054 
 
 0.1088 
 0.0066 
 0.0014 
 0.0082 
 
 0.0088 
 
 
 Candles 
 
 Quicksilver 
 
 0.0071 
 0.0160 
 
 Lumber 
 
 Total cost per ton of ore 
 
 $0.8292 
 
 $0.6718 
 
 $0.7012 
 
 
GOLD-MILLINa IN THE BLACK HILLS AND AT GRASS VALLEY. 15 
 
 Prof. Hofmaii gave the costs for the year ending June, 
 1888. 
 
 It is remarkable how little the increased crushing-capacity of 
 the mills, due to additional stamps, has diminished the costs per 
 ton, and this in spite of the general cheapening of material in- 
 separable from the much improved communication between 
 Deadwood and the centers of industry. This applies especially 
 to the Homestake mill. In the case of the larger plant the 
 diminution of 12 cents per ton, as compared with 1887-88, did 
 not follow the addition of 40 stamps, since previous to that the 
 cost had been 3 cents less. Much of this discrepancy is trace- 
 able to the fact that the wood, fuel, water, castings, foundry- 
 work, etc., are supplied to the mill by subsidiary companies. 
 
 As to the efficacy and completeness of the mills as ore-reduc- 
 tion plants, I find myself (always excepting the feeble attempt 
 at concentration) to be very favorably impressed. It has been 
 urged by unfriendly critics* that " haste and waste " is the chief 
 characteristic of the milling-methods ; but this has been said, 
 I venture to believe, without proper regard to the conditions of 
 the case. 
 
 Something has already been said, in the early part of this 
 communication, regarding the mode of occurrence of the ore. 
 The immense size of the ore-bodies and the extensive nature of 
 the mine developments justify the scale of the Homestake Co. 's 
 operations. The ore is mixed with a large proportion of 
 country-rock in fact, it is for the most part only gold-bearing 
 schist, without any marked boundary or any very noticeable 
 difference between what is worth exploitation (and consequently 
 ore) and what is unprofitable to mine (and therefore waste or 
 " country "). Of the sulphides, the most favorable association is 
 that of arsenical pyrites. But the amount of sulphides present 
 is small, and the gold is not very closely attached to them, so 
 that the ore is notably " free-milling." In fact, in my opinion, 
 it is more docile than even the quartz of the main California!! 
 gold-belt. The results obtained in the mills confirm this view. 
 
 However, it is hard. The wear and tear of shoes and dies 
 indicates this. The shoes wear at the rate of from 36 to 37 
 
 * Kecently by Mr. C. G. Wamford Lock in "Gold Mining and Milling in the 
 Black Hills," read before the Institution of Mining and Metallurgy, London, 
 January 16, 1895. 
 
16 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 pounds per 100 tons of ore, and the dies at the rate of 44 to 48 
 pounds. This represents a cost of only about 2 cents per ton? 
 at the prices which the Homestake Company pays, as compared 
 to 4 cents at Angels Camp* (California), 5J cents in Gilpin 
 county (Colorado), 4J cents at Bendigo and 5J at Clunes (in 
 Australia), 9 cents at Grass Valleyf (California), and 13 cents at 
 Mammoth,J Final county, Arizona. These figures are instruct- 
 ive, but they depend largely on prices and freights. The follow- 
 ing statement of wear in pounds of iron per 100 tons of ore is a 
 better guide : At Angels Camp, 45 pounds ; Grass Valley, 90 ; 
 Gilpin county, 58; Bendigo, 144; Clunes, 157; Mammoth, 76; 
 as against an average of 80J pounds at the Homestake. The 
 ore of Grass Valley is very hard indeed, while the lesser hard- 
 ness of the material treated by the Australian mills is much 
 more than offset by the absence of rock-breakers. The ore of 
 Angels Camp and Gilpin county is comparatively soft. 
 
 At present the Homestake mills save, as far as I could learn, 
 somewhere about 75 per cent. The ore is low-grade. During 
 the year ending June, 1894, the Homestake and Golden Star 
 mills treated 309,210 tons, yielding f 1,390,610, equivalent to 
 $4.49 per ton. Having in regard the low tenor of the ore, the 
 immense reserves of it and the evident intention not to work 
 for the good of posterity, it seems, from a commercial stand- 
 point, a very proper thing to treat it with the utmost dispatch 
 and rush it through the mills. Of course, slower treatment 
 would give a higher extraction, but this would not compensate 
 for the greater cost per ton due to diminished capacity. More- 
 over, the results are not bad; 75 per cent, is an extraction above 
 the average even in mills treating a fraction of the quantity 
 crushed per stamp in this district. The after-treatment, the 
 saving of the sulphides, is a serious error, and the arrangement 
 of the plates is a blemish ; but the excellence of the design 
 of the mortar, the ample rock-breaker capacity and the general 
 arrangement of the mills is such that, taken as a whole, the 
 milling practice is one of the best examples of the cheap treat- 
 ment of a large mass of low-grade ore. 
 
 * In 1891. f In 1892. J In 1893. 
 
 % Placing one tail-plate below two aprons having a combined anialgamating- 
 surface twice as great as the tail-plate. 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 17 
 
 II. GRASS VALLEY. 
 
 Mr. Abadie, in his excellent description of the work at the 
 North Star mill, did not concern himself with the methods of 
 his neighbors at Grass Valley. This was doubtless largely due 
 to the fact that the mill of which he had charge was generally 
 acknowledged as representative of the practice of the dis- 
 trict, 
 
 The following additional matter, based on visits to this dis- 
 trict made in December, 1886, May, 1891, and July, 1893, 
 may, however, render the description of the milling-practice 
 more complete. 
 
 The first mill erected in California was not built at Grass 
 Valley in 1850, as stated* by Mr. Abadie. Mariposa county 
 claims that distinction, and accords it to a mill of 8 stamps, 
 each in its own separate mortar, erected on the Mariposa estate 
 late in the summer of 1850.f It was not till the following Jan- 
 uary that a mill was erected on the west bank of Wolf Creek, 
 nearly opposite the site of the present Empire mill at Grass 
 Valley. 
 
 Mr. Abadie's drawings and photographs very completely illus- 
 trate the position and interior arrangement of the North Star 
 mill. The drawings are particularly valuable. The most 
 notable change made in the North Star mill since my first visit 
 in 1886 has been the new arrangement of the amalgamating- 
 tables. When going through the mill for the first time, I no- 
 ticed the inadequacy of the amalgamating-surface and the use- 
 lessness of the narrow sluice-plates. Since then the shaking- 
 tables have been replaced, in the case of the last two batteries 
 added to the original 30 stamps, by new wide plates which are 
 nearly 16 feet long. The old short apron and narrow sluice-plate 
 have been thrown out. The other six batteries were, at the time 
 of my last visit, and, it would appear, J up to the time of Mr. 
 Abadie's description of the mill, still provided with the primitive 
 apparatus which was first criticized by me nine years ago. 
 
 This is the great blemish of the North Star plant, which has 
 followed in this respect the design of the typical Californian 
 
 * Trans., xxiv., 208. 
 
 f Information derived from Mr. Melville Atwood and others of the pio- 
 neers. 
 
 I Page 215, vol. xxiv. 
 
18 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 mill, whose narrow sluice-plates are a remnant of the appa- 
 ratus originally borrowed by the quartz-miner from the placer- 
 digger. 
 
 In order to discuss this question, a detailed description* of 
 the passage of the pulp on its discharge from the mortar will be 
 necessary. The screen-frame, which is 4 feet 4 inches long and 18 
 inches wide, has four partitions dividing the issue into five 
 portions. Each division of the screen surface is 9 inches wide 
 and 12f inches high. While this construction strengthens the 
 screen, it robs it of 1 square foot of discharging area, and is not 
 therefore to be commended. 
 
 The pulp then drops six inches and strikes the battery-plate, 
 which is 4 feet 2 inches wide and 18 inches deep. It covers an 
 iron apron which is bolted to the mortar. 
 
 Then there succeeds a trough from which the pulp passes 
 through a distributor, consisting of a vertical iron partition 
 pierced by 20 {-inch holes. Then follows a drop of 3J inches 
 to the apron-plate. The latter is 4 feet 5 inches wide f for 2 \ 
 feet, and then becomes narrowed for the remaining 2 feet, fin- 
 ishing with a width of 22 inches. Then come the sluice-plates, 
 22 inches wide and 12 feet long. They had a slope of 1 inch 
 per foot at the time of my visit, but according to Mr. Abadie, 
 the gradient is usually greater, viz., 1 \ inches. The aprons are 
 given 1J inches per foot. 
 
 Then come the copper-lined shaking-tables. The new plates 
 are 16 feet long, of which the upper portion, of 2J feet, is 53 
 inches wide and represents the former apron, and the remain- 
 der is 46 inches wide, representing an enlargement of the 
 sluices. 
 
 Mr. Abadie says that these new plates " cannot be too highly 
 recommended," which is quite true when we contrast them with 
 the old arrangement ; but one may be permitted to ask, Why 
 this narrowing of the plate from 53 to 46 inches ? I take the 
 liberty of emphasizing this matter because it has for many years 
 seemed to me that the California stamp-mill, otherwise the best 
 
 * Much of which appeared in my article on "Grass Valley," published in 
 the issues of May 19 and 26, and June 2, 1894, of the Engineering and Mining 
 Journal, New York. 
 
 t Some of my measurements, obtained by actual measurement in the mill, vary 
 slightly from those since given by Mr. Abadie. 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 19 
 
 machine of its kind yet evolved by the ingenuity of man, suf- 
 fers seriously from an unsuitable arrangement of the amalga- 
 mating surface. In tracing the evolution of the apparatus of 
 the stamp-mill it will be found that the first gold-saving 
 methods were modeled after placer-mining practice, and that 
 in the term " sluice-plate " lingers the evidence of the transfer- 
 ence of the sluice-box from the gulch into the mill. The ar- 
 rangement of 4 feet of plate as wide as the mortar, followed 
 by 10 or 12 feet of plate somewhat under 1 foot wide, was 
 almost universal in California a few years ago, one mill copy- 
 ing another apparently without inquiring into the object of the 
 arrangement. At the North Star an examination of the sluices 
 showed the edges of copper plate to be abraded or scoured by 
 the swift passage of the pulp. 
 
 The philosophy of the sluice-plate is not evident. The bat- 
 tery and apron have caught the coarser gold that which it is 
 easiest to arrest and the object is to prevent the escape of 
 particles which, because they were fine and difficult to catch, 
 have not been stopped. Hence, the sluice-plate is put in, but 
 it is more a launder for the convenient conveyance of the 
 pulp to the vanners than a gold-saving device. How can we 
 expect to catch gold which could not be arrested on a wide 
 plate, by passing it over a very narrow one ? The quantity 
 of water and crushed ore is still the same, but it is crowded 
 into a much lessened space, the speed of its passage is in- 
 creased, and the depth of its flow augmented. In some mills 
 the grade of the sluice-plate is actually greater than that of the 
 apron. 
 
 Therefore the ordinary practice should be reversed, the apron 
 should be succeeded by a wider rather than a narrower plate, 
 additional facilities for the catching of the gold should be 
 given by spreading the pulp so that every opportunity is af- 
 forded for its contact with the amalgamated surface of the 
 plate. 
 
 The necessity for a uniform depth of battery discharge is 
 hardly appreciated at Grass Valley. At the North Star no 
 serious attempt was made to regulate it, so that it used to vary 
 from 2 to 6 inches. Since my last visit it has become the prac- 
 tice to introduce cast-iron plates 2 inches thick underneath the 
 dies. They have lessened the difference between the minimum 
 
20 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 and maximum depths of discharge, according to Mr. Abadie,* 
 to 2 inches. Although his account does not state the fact, yet 
 the context would indicate that these plates are introduced after 
 the dies have been worn down, thereby restoring the height of 
 the issue. At the Empire old dies used to be placed under- 
 neath as the dies in use were worn down, and this was found 
 preferable to employing iron plates for false bottoms (as at the 
 North Star), because the latter broke so often. If they are 
 made to fit snugly, this breakage should be no great detri- 
 ment, as the pieces will remain in place. In addition to these 
 methods, the Empire mill uses the device of fixing wooden 
 cleats to the bottom of the screen outside. The sand banks 
 up inside the mortar, and protects the unused strip of screen 
 until such time as, the dies having worn down, the cleats are 
 removed and the issue lowered. At another mill, the W. Y. O. D. 
 (" Work Your Own Diggings "), the dies are discarded before 
 they have worn down deeply. The remnant is sold to the 
 local foundry, and helps to pay for new dies. This is wise. 
 The consumption of a few pounds of iron is a very small ma1> 
 ter compared to the importance of maintaining the conditions 
 best adapted to good work. When the depth of discharge 
 varies between wide limits, the operation of the mill must be 
 irregular. The minimum and the maximum depths cannot be 
 equally favorable to the particular conditions required, and an 
 effort should be made to find the exact depth best adapted to 
 the treatment of the ores of the special mine, and that figure 
 should then be maintained as far as is practicable. 
 
 In the matter of screens, the Grass Valley mills have, as it 
 seems to me, taken a retrograde step. The general adoption 
 of punched tin-plate in place of wire-cloth is defended on the 
 ground of economy, Thus, Mr. Abadie says that " the life of 
 a tin screen is about 30 days; the cost, one-fourth that of wire 
 screens." As a rule, at Grass Valley, the brass-wire screens 
 cost $1.55 apiece, while the tin-plate costs 55 cents per screen, 
 the former giving a service of 25 days, the latter of 14 to 15 
 days. Steel-wire cloth was discarded because that which was 
 used in this district had the defect of a shifting of the horizon- 
 tal wires. The introduction of tin-plate into the California!! 
 
 * Trans., vol. xxiv., p. 212. 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 21 
 
 mills dates several years back. I first saw it in use at the 
 Utica mill, Angel's Camp, in 1886. In 1893 the Idaho was 
 the only mill in Grass Valley which was not employing tin- 
 plate in preference to wire-cloth. It is the usual custom to 
 burn off the tin upon the blacksmith's forge, with the idea 
 that the iron plate becomes annealed and toughened. Since 
 tin amalgamates, its removal prevents the adherence of mer- 
 cury to the screens. 
 
 The cost of screens per ton of ore varies from j to 1 cent per 
 ton, an item of expense which is trifling when compared to 
 the importance of getting a screen which will properly size the 
 pulp and aid in maintaining the conditions most favorable to 
 good amalgamation. As between punched tin-plate and wire- 
 cloth, the advantage in cheapness possessed by the former need 
 not be considered unless it accompanies other more serious ad- 
 vantages ; the difference of half a cent this way or that is as 
 nothing when measured against good milling. 
 
 No one at Grass Valley had, as far as I could learn, made any 
 careful experiments to determine the action upon the pulp of 
 the use of the two varieties of screen. One would naturally 
 expect* a more free issue and a more uniform crushing when 
 using wire-cloth in place of punched plate, f because the former 
 has a discharge-area approximately one-half of its surface, J 
 while the latter, having apertures of the same size, has less of 
 them per square inch. 
 
 In making such tests it is necessary to be particularly careful, 
 not only that the- same kind of ore is fed and that the mortars 
 are the same, but also that the shoes and dies are in the same 
 state of wear, so that the depth of discharge is equal in both 
 batteries. Moreover, attention should be paid to the possibility 
 
 * The only results of experiment published are those contributed by Mr. Thos. 
 H. Leggett to the Eng. and Mining Journal of June 30, 1894, where it is shown 
 that as between a round punched tin, No. screen and a 40-mesh steel cloth, the 
 former made nearly 11 per cent, less fines (passing through a 100-mesh screen) 
 than the latter. 
 
 f A recent test at the Mammoth mill, Final county, Arizona, showed that as 
 between a No. 6 slot-screen and an equivalent wire cloth, 24-mesh and 26 B. W. 
 G. wire, the latter crushed 20 per cent, more than the former. 
 
 J With a width of mesh .027, a thickness of wire .01, and a gauge (B. W. G.) 
 of 33, the discharge-area is just one-half the total surface. 
 ' % See also Trans., xxiii., 563. 
 
22 GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 
 
 of more fine stuff finding its way into one mortar than into the 
 other. The outer hatteries of a stamp-mill, where the rock- 
 hreaker is in the center, receive more than their share of the 
 fines. 
 
 The milling-practice of the Grass Valley district has under- 
 gone important changes during the past ten years. The intro- 
 duction of an inside amalgamating-plate first done at the 
 North Star in 1888 marked an important departure from the 
 extreme type of fast-crushing California battery. The tendency 
 to increase the percentage of inside amalgamation hy deepening 
 the discharge and inserting a chuck-block (which also carries an 
 amalgamating-plate) is a notable feature. Thus from a rapid 
 pulverizer the California mill has been made an improved 
 amalgamator. This older, very shallow-drop mill, unable to 
 use a plate inside the mortar, and relying solely on the outside 
 tables, has become rare on the Pacific slope. It has become 
 a recognized fact that rapid crushing will not compensate for 
 poor amalgamation; that the sooner we catch our gold the 
 better ; and that the best feature of the stamp-mill, as compared 
 to other pulverizers, is its capability to combine the crushing 
 and amalgamating apparatus in one machine. 
 
 At the North Star and W. Y. 0. D. mills nearly twice as 
 much amalgam is obtained from the inside as from the outside 
 of the -mortar ; while at the Empire the inside extraction is 
 from 50 to 85 per cent, of the total saving. 
 
 Heavy silver-plating is recommended nowadays. The North 
 Star plates carry 1 ounce of silver per square foot, those of 
 the Empire have 2J ounces, while at the W. Y. O. D., the newest 
 plant, the amount has been increased to 5 ounces. One cannot 
 remember too often that it is amalgam that catches gold, and 
 that a good coating of gold-amalgam is better than all the nos- 
 trums in creation. In starting a new mill or introducing new 
 plates a good coating of silver helps to get the tables into work- 
 ing order in a short time, the silver being gradually replaced by 
 gold. There is no economy in poorly-plated tables or in short, 
 narrow ones. No mill I have ever seen had too mucji amal- 
 gamating-surface ; many of them have had too little. The 
 value absorbed by the plates is an asset of the best kind; and 
 there is no plate placed in a mill but will absorb some gold and 
 be worth more when it is worn out and discarded than wheli 
 
GOLD-MILLING IN THE BLACK HILLS AND AT GRASS VALLEY. 23 
 
 it was first put in place. The following fact* will be of interest 
 in this connection. The old plates of the 60 stamp-mill of the 
 Montana Co., Ltd., at Marysville, Montana, after 4J years' 
 steady work, 1887-1891, were scraped and melted down. (This 
 was, of course, after they had undergone the usual periodical 
 clean-up.) The 12 plates, each 54 by 96 inches, yielded $90,- 
 000. One plate gave as much as $8000. Even the small vanner 
 plates, f 16 by 48 inches, yielded $500 each. 
 
 The importance of the careful sampling of the tailings as a 
 check upon the mill-work is better appreciated at Grass Valley 
 than in any other locality I have visited. At the Empire mill 
 there is an automatic sampler, invented by Mr. Starr, the former 
 superintendent, which does excellent service. The results in- 
 dicate a saving of from 85 to 87 per cent., which is fairly repre- 
 sentative of the district. 
 
 * Which I owe to Mr. B. T. Bayliss, the general manager of the Montana 
 Co., Ltd. 
 
 f In the neighboring 50-stamp mill. 
 
SUBJECT TO 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Veins of Boulder and Kalgoorlie. 
 
 BY T. A. RICKARD, DENVER. 
 (New Haven Meeting, October, 1902.) 
 
 COMPARISONS frequently do good service by affording a 
 means of distinguishing the features which are essential from 
 those which are merely accidental. When one reads of the 
 lode-structure of a new, and perhaps distant, gold-field, there 
 arises the desire to compare the characteristics mentioned with 
 those of the regions with which one is already familiar. It 
 will therefore be interesting to refer to the other districts with 
 which Cripple Creek has been likened. 
 
 A. THE VEINS or BOULDER COUNTY, COLORADO. 
 
 Telluride-ores have been mined in Colorado since 1872. 
 Previous to 1891, when Cripple Creek was discovered, the 
 principal localities for such ores were the La Plata mountains 
 and Boulder county. The former district is situated in the 
 extreme southwestern part of the State. Boulder is about 90 
 miles due north of Cripple Creek, in that part of Colorado 
 which was first opened up by the pioneers of 1859. The 
 prevailing rock is the granite-gneiss of the Front range. The 
 veins are notably associated with bands of chloride gneiss, to 
 which the French geological term of " protogine " was formerly 
 applied. Dikes of quartz-porphyry and quartz-andesite occur 
 at frequent intervals. In this respect Boulder resembles the 
 adjacent well-known district of Gilpin county, but the ore- 
 occurrence does not appear to be as intimately connected with 
 the dikes as it undoubtedly is in Gilpin. 
 
 The veins of Boulder appear to be bands of crushed rock 
 accompanying lines of fracture which have been healed by the 
 impregnation of ore. Fig. 1 will illustrate this characteristic 
 type. The Enterprise is the principal lode of the El Dora dis- 
 trict, 011 the western border of the county. The enclosing 
 formation is granitoid-gneiss, traversed by belts of protogine 
 
2 THE VEINS OF BOULDER AND KALGOORLIE, 
 
 and mica schist. In this instance a band, 8 inches thick, of clay, 
 called " gouge " by the miners, and consisting of rock crushed 
 to the condition of mud, follows the hanging-wall, which ap- 
 pears as a distinct parting, separating the lode, A C, B D, from 
 the enclosing country-rock. Next to the " gouge " comes a well- 
 defined strip, 3 to 4 inches wide, of casing, which is made up of 
 brecciated gneiss so laminated as to resemble a shale. The 
 foot-wall is not very distinct, because the lode-matter merges 
 insensibly into the country-rock. The ore, Gr H, appears in the 
 form of dark threads of flinty quartz arranged in parallel lines 
 amid the lode-stuff, which is essentially a granular matrix of 
 partially-crushed granite-gneiss. The dark quartz carries 
 finely-disseminated tellurides, chiefly petzite, which renders a 
 width of 2 to 2J feet sufficiently rich to yield an average of 2 
 ounces of gold per ton. 
 
 The Monongahela vein, shown in Fig. 2, occurs at Sunshine, 
 in the central part of Boulder county, and resembles a score of 
 similar lodes to be seen in the small mines which yield the bulk 
 of gold from this interesting region, and are intermittently 
 worked under lease by parties of experienced miners. Fig. 2 
 represents the eastern face of the 100-ft. level in the Monon- 
 gahela workings as seen in April, 1897. The most prominent 
 feature of the section is a dark band (A E, C H) of " horn- 
 stone," or flinty quartz, which, on closer examination, is found 
 to be composed of two separate streaks, A F-C G- and F E-G 
 H, in both of which specks of petzite are clearly distinguish- 
 able. The upper portion, 3. inches wide, has numerous cavities, 
 " vughs," lined with crystalline quartz and marcasite (white 
 iron pyrites). The lower one, 2J inches wide, is more com- 
 pact. Between the pay-streak (A E, C H) and the foot-wall 
 (B D) there is a thickness of 7 inches of dark-gray quartz, 
 through which patches and streaks of granular protogine are 
 distributed. This band carries only traces of gold. It marks 
 the transition between ore and country-rock. There is no dis- 
 tinct hanging-wall. A narrow width of crushed country, A C, 
 separates the pay-streak from the enclosing rock. The latter is 
 traversed by several dark threads of flinty quartz, which may 
 be regarded as feeders to the vein proper. 
 
 A little further west the pay-streak splits into two dark fila- 
 ments of hornstone, separated by mottled quartz, and the lode 
 
THE VEINS OF BOULDER AND KALGOORLIE. 
 
 E 
 
 Granitoid Gneiss 
 
 Clay 
 
 Quartz 
 
 Casing 
 
 N .i //(Crushed Rock 
 
 ENTERPRISE VEIN. EL DORA, COLO. 
 
4 THE VEINS OF BOULDER AND KALGOORLIE. 
 
 becomes more valuable. This change is illustrated in Fig. 3. 
 The band (E B, H D, in Fig. 2) of quartz containing inclusions 
 of country-rock has thinned out, and finally disappeared. The 
 double streak of ore (A F-C G and F E-G H in Fig. 2) has 
 separated into two threads (E K and F L in Fig. 3) of banded 
 hornstone, containing frequent cavities lined with quartz-crys- 
 tals. Between these two threads there is a width of 5 inches of 
 dark mottled hornstone, containing tellurides, and forming, 
 therefore, rich ore. The small thickness, A C, of altered 
 country to be seen on the hanging-wall side in Fig. 2 has be- 
 come amplified in Fig. 3 to a 3-inch casing, C G, of crushed 
 rock, and a further width, D H, of 6 inches of breccia, con- 
 sisting of fragments of protogine cemented by brown quartz. 
 The lode, which may be considered as extending from 
 C to F and from G to L, is in protogine, and consists of that 
 rock in variously altered condition, graduating from crushed 
 country-rock, C G, to crushed rock impregnated with quartz, 
 D H, and finally into a clean, dark, siliceous matrix, E F, K L, 
 to which the term " hornstone "* can be fitly applied. The 
 nature of the ore-occurrence can be further inferred from the 
 gold-contents of the various portions of the lode. Thus, C G 
 was poor, that is, it contained ^ of an ounce or so of gold per 
 ton; H D carried 8 ounces of gold per ton; and the main 
 streak, E F, K L, was worth, at the time of my visit, from $2.50 
 to $5 per pound. The band H D becomes at times so impreg- 
 nated with dark quartz as to merge into the main streak of 
 ore. 
 
 There is no selvage separating the ore-streak, E F, K L, 
 from the enclosing rock. The seam of black hornstone, 
 F L, is " frozen " to the foot-wall. This " hornstone " is a 
 characteristic feature of the telluride-bearing streaks of Boulder 
 county. It is essentially massive, compact silica, otherwise 
 chalcedony or flinty quartz, darkened by the presence of finely 
 disseminated particles of iron pyrites (chiefly marcasite) and the 
 
 * The miners, by evident confusion, called the dark, flinty veinstone " horn- 
 blende," instead of " hornstone," and in the same manner they had converted 
 " vugh-hole" into "bug-hole." Hornstone is good Anglo-Saxon, horn meaning 
 resembling horn in being callous or hard, as in "horny-handed son of toil." 
 The word " chert " is nearly a mineralogical equivalent for hornstone. Chert is 
 Irish, and originally meant " pebble." 
 
THE VEINS OF BOULDER AND KALGOORLIE. 
 FIG. 2 A F E 
 
 ~"~ '" '' 
 
 1 - ' ' '' l '' 11 
 
 
 P^4\\W>~'~<~'~' "V '- -- v -'-' 
 Ml\j--\\W'V'-, "\-r -,. , , 
 
 ''V''V r r--, --* sp - "'" ^'J 1 :.:':': 1 A' ::'::' jj 
 
 ^'V-'-lvVV^vffll^H^ 
 
 '^'' : 'r^-^ 
 
 CT/ I _-.-.'_ -_ - 
 
 III/' l ' ' '''_''' 'j '-' 'j 
 
 vv" " " r . 'V'~ r , r . ' 
 
 Hornstone 
 
 Quartz 
 
 MONONGAHELA VEIN, BOULDER COLO. 
 
6 THE VEINS OF BOULDER AND KALGOORLIE, 
 
 tellurides of gold and silver (either petzite or sylvanite). The 
 richer portions are frequently characterized by the presence of 
 prochlorite and roscoelite. The latter, which is a vanadium- 
 mica, of a brownish-green color, is so notably associated with 
 the valuable ores of Boulder that the miners have got into the 
 way of considering it an essentially gold-bearing mineral. It 
 occurs in the lodes of Kalgoorlie, in West Australia, and quite 
 recently it has been found in the " Last Dollar," " Mary 
 McKinney," and other mines in the Cripple Creek district.* 
 
 B. THE LODES OF KALGOORLIE, WEST AUSTRALIA. 
 
 Kalgoorlie shares with Cripple Creek the honor of having 
 brought tellurides to the front rank among the ores from which 
 gold is won. The two districts have been likened, but erro- 
 neously. Their geological unlikeness is their most interest- 
 ing feature. 
 
 The veins occur in chloritic schist, the vein-stuff being essen- 
 tially the same as the encasing country-rock, but more schistose 
 in structure and more calcareous in composition. There has 
 been much discussion among petrographers concerning the 
 original character of the country enclosing the veins.f The 
 alteration in the rock induced by extreme metamorphism has 
 rendered the conclusions of observers anything but unanimous. 
 In the district itself the term " diorite " is loosely employed 
 by the mine-managers to describe the prevailing formation, but 
 microscopic sections exhibit a good deal of quartz and no horn- 
 blende, and therefore prove that term to be inappropriate. 
 Some feldspar can be detected. Titaniferous iron and mica are 
 present. From sections which I secured in 1897 Prof. Judd, 
 F.R.S., concluded that the prevailing rock was a highly altered 
 quartz-andesite. As the formation appears underground it is 
 a fine-grained foliated rock or schist with a silvery-green sheen 
 and a fissile structure. It is rendered tough, and also soft, by 
 
 * See "The Telluride Ores of Cripple Creek and Kalgoorlie," Trans., vol. 
 xxx., pp. 708-718. Fine specimens of roscoelite have been lately obtained from 
 the Logan mine, near Crisman, in Boulder county. Roscoelite is named after Sir 
 Henry E. Roscoe, the celebrated chemist. 
 
 f Most of the evidence on this mooted point is well summarized by Mr. George 
 W. Card, in vol. vi., part i., "Records of the Geological Survey of New South 
 Wales," 1898. 
 
THE VEINS OF BOULDER AND KALGOORLIE. 
 
 C E F 
 
 I ' ' v I 
 
 r "r -~ i . ' 
 
 , I \ -'-, /\/ V 
 
 ~- i"" I N ' XX ' ' 
 
 '" > 
 
 , 
 
 - 
 
 ' 
 
 j ' '_-/'_ -U -'-^ V-< 
 
 jHornstone /Vugn 
 
 MONONGAHELAVEIN, NO. 2 
 
8 
 
 THE VEINS OF BOULDER AND KALGOORLIE. 
 
 reason of the calcite and sericite (or hydrous mica) which it 
 carries. 
 
 A typical lode is illustrated in Fig. 4, which shows the face 
 of the 270-ft. level in the Great Boulder Main Reef mine, on 
 Oct. 18, 1897. It is a schistose band of rock with a well- 
 
 FIG. 4 
 
 p TAR 1807 
 
 (4 Quartz and Calcite 
 
 A K'ALGOORLIE LODE 
 
 defined line of parting, A F. This " east wall," as it is termed, 
 forms one boundary of the gold-bearing rock, that is, the lode, 
 which has no denned limit on the west, but graduates into the 
 country-rock on that side. There is an evident struggle between 
 two systems of fracture ; the rock which is ore-bearing, A C, 
 
THE VEINS OF BOULDER AND KALGOORLIE. 9 
 
 D F, is sheeted along lines which are nearly upright and paral- 
 lel to the parting, A F, while the surrounding country has a 
 contrary cleavage. The ore differs further from the surround- 
 ing rock in being traversed hy veinlets of calcite and granules 
 of quartz arranged along the lines of fracture. Iron pyrites is 
 also liberally scattered through this calcareous vein-stuff. 
 Petzite and calaverite gave the lode here illustrated an average 
 value of 3 \ ounces of gold per ton. 
 
 The telluride-ores of Kalgoorlie appear sometimes to occur 
 in long, overlapping lenses, as is illustrated in Fig. 5, which 
 represents a series of ore-bodies cut at the third level of the 
 Lake View Consols mine. It is said that the original owners 
 of this now famous property followed the line of one of these 
 long, torpedo-like lenses, and, not knowing the nature of the 
 occurrence, their workings ran out into barren country so as to 
 necessitate a cross-cut, which, unfortunately, was put out on the 
 wrong side, with the final result that they concluded, as the 
 Cornishman would say, u that the lode had just naturally 
 petered out." The ore tends to spread from one plane of folia- 
 tion in the schist to the next one on the right, with the result 
 that the longer axis of each lens makes a small angle with the 
 strike of the country, and the successive lenses follow one 
 another en echelon.* An occasional " wall" may be prominent 
 and the ore may follow it for a short distance, but it will leave 
 it for another, equally well-marked. The " walls " or planes of 
 parting do not limit the ore-channel ; some of them are within 
 it, some extend beyond it, to become faint as they are followed 
 into the surrounding country. In the space separating the 
 lenses there are stringers and small seams of ore which serve 
 as connecting threads of discovery. They act as "leaders,"t 
 guiding the observant miner from one ore-body to another. 
 
 The description of veins in two districts so far apart on the 
 map as Boulder in Colorado and Kalgoorlie in West Australia 
 emphasizes the diversity of structure characteristic of the lodes 
 which carry gold. Both types of veins occupy fractures which 
 
 * A military term descriptive of the movement of troops advancing in diagonal 
 step-like succession. 
 
 t This is an Australian term which is worthy of adoption. Leader is from the 
 A. S. Iredan, to guide, just as lode is from lad, a path. A lode is the occurrence 
 of ore which guides or leads a miner. 
 
10 
 
 THE VEINS OF BOULDER AND KALGOORLIE. 
 
 X Ol 
 
 X X| 
 
 X 
 
 I X x X X 
 
 X 
 
 A % ,X 
 
 Q , 
 
 X 
 
 X 
 
 X X 
 
 X 
 
 . Jx x x 
 x x .x 
 
 V v 
 
 x V 
 
 X 
 
 X 
 
 X 
 
 X ^ 
 
 X 
 
 x 
 
 X 
 
 y 
 
 X ' fl X 
 
 1 x /l 
 
 X 
 x * 
 
 X V 
 
 ^ y 
 
 u 
 
 X 
 
 r 
 
 / x 
 
 o 
 2 
 
 UJ 
 
 cc 
 
 (T 
 
 ID 
 O 
 
 u 
 o 
 
 UJ 
 
 cc 
 O 
 
THE VEINS OF BOULDER AND KALGOORLIE. 11 
 
 have been healed by mineral solutions ; the Boulder type is dis- 
 tinctly a segregation of amorphous quartz in the form of flint, 
 with a cementing of the adjacent granite, which had been 
 brecciated at the time of the formation of the vein fracture ; 
 the Kalgoorlie type represents a sheeting of the schistose coun- 
 try without any clean-cut fissuring and without a brecciation 
 of the country, which, being more tough than a granular rock, 
 such as granite, and less fissile, exhibits the effects of strain in 
 a system of parallel sympathetic partings, along which calcite 
 and quartz have been deposited, and, with them, the tellurides 
 of gold. In the Boulder type the tendency is to produce tab- 
 ular ore-bodies known as " shoots " ; in the Kalgoorlie type the 
 struggle between schistosity and sheeting, along a sheer zone, 
 produces " lenses.'' 
 
 BY THE SECRETARY. Comments or criticisms upon all 
 papers, whether private corrections of typographical or other 
 errors or communications for publication as "Discussions," or 
 independent papers on the same or a related subject, are earn- 
 estlv invited. 
 
SUBJECT TO REVISION. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Indicator Vein, Ballarat, Australia. 
 
 BY T. A. RICKARD, STATE GEOLOGIST, DENVER, COLORADO. 
 
 (Canadian Meeting, August, 1900.) 
 
 IN " The Genesis of Certain Auriferous Lodes "* Dr. Don 
 makes a reference to a curious vein-formation known as the 
 "Indicator," which characterizes a portion of the Ballarat 
 mining district, in Victoria, Australia. During 1890 and 
 again in 1898 I had an opportunity of making a few notes, 
 which, although somewhat belated, f may be worth adding to 
 the observations recorded in the Transactions of the Institute. 
 
 The country of the Ballarat gold-field consists of the Lower 
 Silurian slates and sandstones, which also enclose the reefs of 
 Bendigo; but it is noteworthy that the successive anticlinal 
 folds, and accompanying saddles of quartz, which distinguish 
 Bendigo are not characteristic of Ballarat, the geological struc- 
 ture of which presents greater complexity. . 
 
 That part of the district known as Ballarat East became 
 famous early in its history on account of the large nuggets 
 which were found in the alluvium, and subsequently it became 
 further known because of a peculiar persistent black seam, 
 traversing the bed-rock underlying the alluvial deposits, which 
 was found to be associated with rich bunches of gold-ore, not 
 only in the gravel that capped it at the surface but also in the 
 quartz-veins which crossed it underground. The name of 
 " Indicator " was early given. In 1871 Mr. Morgan Llewellyn 
 directed attention to it as influencing the distribution of the 
 gold. In the government quarterly report for December, 1888, 
 
 * Trans., xxvii., 564 et seq. 
 
 t The treatise contributed by Dr. Don reached me while making a second visit 
 to the very localities among which he has gathered so much valuable evidence. 
 Most of the lodes to which he refers came under my own observation in 1889-91, 
 and though I have omitted until now to join other members in acknowledging the 
 great usefulness of Dr. Don's contribution to the science of ore-deposits, it is 
 solely due to the fact that I had hoped long ago to do so in a manner which he 
 would most appreciate, that is, by contributing further data to the investigations 
 in which he has been engaged. 
 
2 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 Mr. E. J. Dunn described* a similar occurrence observed by 
 him in the neighboring district of Wedderburn. In Septem- 
 ber, 1893, the writer contributed a note on the subject, f Mr. 
 Ernest Lidgey, of the Geological Survey of Victoria, made a 
 special report^ on the Ballarat East gold-field, which was pub- 
 lished in 1894. In 1895 and again in 1897 Mr. "William Brad- 
 ford added further data. 
 
 Mr. Bradford, who lives at Ballarat and has made a careful 
 study of the district, describes the Indicator as " a pyritic 
 sheet, varying in width from one-eighth of an inch to about an 
 inch, which has been formed in an almost parallel line with the 
 
 \\.\ SANDSTONE \>////\ SLATE 
 
 The Indicator. (After William Bradford.) 
 
 line of the strata. See sketch." The sketch referred to is re- 
 produced in Fig. 1. Another good illustration from his later 
 paper on the subject is reproduced, with slight modifications, 
 in Fig. 2. The indicator is the dark thread G B, C H, which 
 is dislocated from B to C by the fault-line AD. F B, C E is 
 a flat seam of quartz which is also faulted, with enrichments at 
 B and C, the points nearest to the Indicator and to the later 
 line of fracture, A D. In his description of this occurrence 
 he says : 
 
 * "Report on the Country in the Neighborhood of Wedderburn and Rheola," 
 by E. J. Dunn. Quarterly Rep. of the Mm. Dept. of Victoria, 1888. 
 
 f "Certain Dissimilar Occurrences of Gold-Bearing Quartz." Proc. Col. Sti. 
 Soc., vol. iv., pp. 329-331. 
 
 J "Report on the Ballarat East Gold-field," by Ernest Lidgey, assistant geo- 
 logical surveyor. 
 
 $ "The Indicator Feature in Some Gold-Occurrences," by William Bradford. 
 Trans. Austral. Inst. of Min. Enyrs., vol. iv. 
 
THE INDICATOR VEIN, BALLABAT, AUSTRALIA. 
 
 3 
 
 " Flat make of quartz displaced by a slide break. Nuggety gold was met with 
 at the point where the Indicator intersected the quartz on the higher side of the 
 break. Down the line of the break a layer of gold in the form of fine particles 
 was found, and traced to the point where the lower part of the quartz occurrence 
 abutted on the break." 
 
 Mr. Dunn, the distinguished geologist, whose work on the 
 neighboring gold-field of Bendigo is well known to the mem- 
 bers of this Institute, describes the Indicator at Wedderburn 
 as being a " bed of rock of dark-grey to black color, and from 
 
 Fig. 2 
 
 SCALE, 'S FEETj 
 
 The Indicator Faulted. (After William Bradford. ) 
 
 5 to 7 inches wide, made up of thinly laminated unctuous clay." 
 His illustrations are reproduced in Fig. 3. 
 Mr. Lidgey, in his special report, says : 
 
 "These indicators are usually thin beds of dark-colored shales and slates, 
 formed of a carbonaceous mud, containing a large percentage of iron sulphide. 
 They are parallel, and, so far as worked, nearly vertical, any change from the 
 vertical being usually due to the presence of faults." 
 
 The most persistent of the series, known as " The Indicator," 
 
4 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 he describes as " a narrow bed of dark slate, usually showing 
 cleavage planes, and containing a large percentage of pyrite, 
 distributed irregularly through it." In Fig. 4 a series of Mr. 
 Lidgey's illustrations is reproduced. 
 
 Finally, in Fig, 5, I have added the drawing* exhibited by 
 me in 1893 to the Colorado Scientific Society, from a sketch 
 made at the 700-ft. level of the New Normanby mine on Feb- 
 ruary 25, 1891. 
 
 HORIZONTAL 
 
 Plans of the Indicator at Wedderburn. (After E. J. Dunn, F. G. S.) 
 
 "Whatever differences may be remarked in the foregoing 
 descriptions are explained by the changes which this remark- 
 able vein undergoes in its passage for seven or eight miles 
 through a long series of mines, extending from Black Hill to 
 Bunninyong. 
 
 Mr. Lidgey's report is accompanied by maps of the Ballarat 
 East district, exhibiting the course of the Indicator through a 
 series of claims belonging to various companies. A part of 
 
 * This drawing was reproduced by Dr. Don, on p. 7 of his treatise, and in his 
 paper, Trans., xxvii., 570. 
 
THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 these maps is reproduced in Figs. 6, 7 and 8*, which represent 
 the plan, cross-section and longitudinal section of the ground 
 near the Prince Regent mine. Further evidence is given in 
 Figs. 9 and 10. Fig. 9 is a photographf taken at the 500-ft. 
 level of the No. 1 Llanberris mine. Fig. 10 is a diagrammatic 
 interpretation which will, it is believed, aid the decipherment 
 of the details in Fig. 9. The photograph shows the Indicator 
 (at A B), and the foot-rule J affords a scale of measurement ; 
 yet, as in most underground photographs, the dark seams are 
 confused by lines of shadow, and it is not possible to distin- 
 guish the slates from the sandstones, both being dark-grey and 
 
 Fig. 4 
 
 567 
 Diagrams Accompanying Report on Ballarat East. (After E. Lidgey. ) 
 
 both showing cleavages. Nevertheless, it is a valuable piece 
 of evidence, comparatively untainted with the subjective ele- 
 ment which vitiates a sketch. 
 
 By way of supplementary testimony I add Figs. 11 and 12 
 from sketches made during my last visit to Ballarat, in Janu- 
 ary, 1898. In Fig. 11 the Indicator is shown as seen at the 
 
 * These three drawings must not, I think, be taken too literally ; for I note that 
 the stratification of the slates and sandstones is repeatedly shown as unbroken 
 where traversed by cross-courses which, as is well known, fault the country. 
 Such errors are doubtless due to the departmental draughtsman who prepared the 
 drawings, and do not represent any error of observation on the part of Mr. Lidgey 
 himself. It was the dislocation of the Indicator series that the drawings were 
 intended to represent ; and this they do satisfactorily. 
 
 t Thi excellent photograph was kindly given to me by Mr. Lidgey in 1898. 
 
 + Which, it should be noticed, is extended so as to cover a length of 2 feet. 
 
6 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 770-ft. level of the Prince Regent mine, where it is dislocated 
 by a flat seam of quartz which carries coarse gold at the cross- 
 
 Fig. 5 
 
 The Indicator," New Normanby Mine, Ballarat, Australia. 
 
 ing. The Indicator evidently conforms to the bedding of the 
 slate band, of which, indeed, it forms a part. 
 
 The Metropolitan lode, illustrated in Fig. 12, occurs in an 
 
THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 7 
 
 adjacent portion of the Ballarat district. It has, on a large 
 scale,* certain of the features which characterize the geological 
 structure of the Indicator series, and for this reason it is placed 
 in evidence here. The Metropolitan lode consists of a series 
 of spreading quartz-seams, to be considered as branches thrown 
 out by nearly vertical veins, traversing a band (A B, C D) of 
 thinly-bedded slates and sandstones, and dips slightly westward 
 from the vertical. This band, which is enclosed by a series of 
 massive beds of sandstone, forms a lode, or lode-channel, 80 
 ft. wide, in which the quartz-seams first referred to rarely ex- 
 ceed 7 or 8 ft. in thickness, and, having an easterly dip, cross 
 the bedding almost at right angles. The cross-veins recognize 
 the structure of the rocks they traverse by a succession of drops 
 as they meet the successive seams of slate. The gold-occur- 
 rence is also modified by this structure, the richest quartz being 
 found at the crossing of the slates, and especially upon the 
 lower or eastern side. The quartz composing these seams is 
 white " as a hound's tooth;" but occasionally, in the slate, it is 
 besprinkled with a little arsenical pyrite. 
 
 The Indicator is essentially a very thin thread of black slate, 
 which is remarkable on account of its extraordinary persistence, 
 and also because the quartz seams which cross it are notably 
 enriched at the place of intersection. In certain parts of Bal- 
 larat East the Indicator has coincided with lines of movement, 
 and having, on this account, undergone attrition, it now ap- 
 pears as a seam of clay. At other places it is so impregnated 
 with iron pyrites as to have the characteristics of a sulphide 
 streak. When it is met by quartz-veins carrying galena and 
 zinc-blende it partakes of their mineralization. At the end of 
 the 700-ft. level in the New Normanby mine it was slightly 
 over one-sixteenth of an inch thick, and consisted of crushed 
 black slate, in which small crystals of pyrites were embedded. 
 In a cross-cut nearby it appeared as a thin vein of quartz. This 
 is an infrequent modification, and one which is found by expe- 
 rience to be unfavorable to the occurrence of rich ore. At the 
 770-ft. level of the Prince Eegent mine the Indicator had the 
 thickness of an English penny, and was freely studded with 
 crystals of arsenical pyrites, tarnished by oxidation. 
 
 The belt of slates and sandstones constituting the prevailing 
 
 * The scale of Fig. 12 represents feet, and not inches, as in Fig. 11. 
 
8 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 geological formation of the district is marked by a peculiarly 
 persistent series of thin seams of black slate. The Indicator 
 is the chief member of this series, by reason both of its per- 
 sistence and of its economic importance as marking a line of 
 particular enrichment. The others are variously known as the 
 " Western Indicator," the " Pencil Mark," the " Nuggety 
 Slate," "Dunk's Slate," "The Streaky Slate," etc., an odd 
 nomenclature, originating with the miners, who have been 
 quick to recognize these various " leaders," as they have been 
 encountered in the workings underground. This series is 
 crossed by a later system of quartz-veins and stringers, inter- 
 secting the bedding of the sedimentary rocks almost at right 
 angles, and lying, therefore, approximately flat, with a slight 
 dip northeast. Occasionally, large quartz-veins are seen follow- 
 ing the planes of bedding; but such as do so, appear invariably 
 to be poor. Those which cross the Indicator (and its com- 
 panion-seams) are gold-bearing, but only at the places where 
 they intersect the Indicator, and, as will have been noted in the 
 illustrations, fault it. Therefore the workings follow the Indi- 
 cator in such a way that the rock removed includes 2 or 3 ft.* 
 on either side of it. The intersecting quartz-seams are so fre- 
 quent that the entire band along the line of the Indicator is 
 treated as a gold-bearing lode. Poor zones occur. Thus the 
 Prince Regent mine has found no pay-ore on the Indicator be- 
 tween the 550-ft. level and the 770-ft. level. The Speedwell 
 mine traversed a barren interval between 400 and 500 ft., but 
 is said to have become profitable lower down. There is, how- 
 ever, at the present time, a general tendency toward impover- 
 ishment in the deeper workings of the group of mines occu- 
 pying the Indicator belt. 
 
 The series of quartz-seamsf which intersect the Indicator 
 are not to be considered as isolated lenticles, but must be re- 
 garded as part of an extensive system of flat veins, which are 
 lateral embranchments from the nearly vertical ones to be seen 
 following the bedding of the slates and sandstones, as, for ex- 
 ample, along B D, in Fig. 12. The workings of the mines ex- 
 hibit frequent lines of faulting, or " slides," which dislocate the 
 entire series referred to, i.e., the Indicator, the quartz-seams en- 
 
 * As a rule a few inches on either side of the Indicator represents the entire 
 width of the pay- ore, but 4 to 5 ft. is necessarily removed for convenience of ex- 
 ploitation, f The Australian miner calls these "makes of spurs." 
 
THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 9 
 
 riched by it, and the enclosing slates and sandstones. These 
 " slides " carry clay and exhibit the other characteristics of 
 planes along which a movement of the rocks has taken place. 
 
 Mr. William Chisholm, the manager of the Prince Regent 
 mine, who is thoroughly familiar with the geological structure 
 of this part of Ballarat, regards the impoverishment below the 
 
10 
 
 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 _ _CR08SfpUR8E NO. 29 
 / 1 T 
 
THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 11 
 
 550-ft. level as connected with the " big slide " which cuts 
 through the shaft 540 ft. below the surface and shifts the Indi- 
 cator series 55 ft. westward. The managers of the neighbor- 
 ing properties also connect similar disturbances encountered in 
 the workings of their mines with the diminution in the rich- 
 ness of the series of flat quartz-veins. Dr. Don takes this view, 
 and confirms it with analyses of samples taken in the Prince 
 Regent mine, which prove that the solid country enclosing the 
 veins is not itself gold-bearing, while the clay accompanying 
 
 yy__SURFAC_ E 
 
 Fig. 8 
 
 DALZELL PRINCE REGENT 
 
 Cross-Section of Fig. 6. (After E. Lidgey, Geological Survey of Victoria, ) 
 
 the fault-fracture is rich in gold. In both cases, the presence 
 of gold bore no relation to the richness or poverty of the neigh- 
 boring Indicator. 
 
 These views seem to me to be in accord with the evidence ; 
 but until the present horizon of impoverishment which charac- 
 terizes the lower workings of the mines of Ballarat East is 
 succeeded, deeper down, by a horizon of enrichment, one is 
 scarcely warranted in speaking of " zones." My experience is, 
 I believe, in accord with that of most of us, in recognizing the 
 
12 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 fact that gold-veins often get poorer in depth ; and this occur- 
 rence is so frequent that a particular explanation, like the one 
 
 FIG. 
 
 The Indicator, 500-ft. Level No. 1, Llanberris Mine. 
 
 above mentioned, gains no force by being connected with such 
 a general fact. A zone of impoverishment is usually only a 
 
THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 Fig. 10 
 
 13 
 
 kWfrA*J?$ feli?l5* 
 
 ' ' \[ I SLATE AND SANDSTONE. I INDICATOR, 
 
 The Indicator. Diagram, Explaining Fig. 9. 
 
 euphuism calculated to obscure the frank recognition* of things 
 as they are. 
 
 * I was glad to read Dr. Don's frank statement (op. cit., p. 596) concerning this 
 matter of impoverishment below the water-level. Science has to do with facts ; 
 
14 
 
 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 The enrichment of the selvage accompanying the fault- 
 planes, as proved by Dr. Don, is very suggestive. If these 
 faults served as passages for the upward circulation of the gold- 
 bearing solutions which precipitated a part of their precious 
 burden, en route, and the remainder when the Indicator seams 
 were intersected, then we have a very pretty example of ore- 
 Fig. 1 1 
 
 M 
 "ill 
 
 1 2 :i 4 5 
 SCALE OF INCHES 
 
 Kl-" 
 
 I' 
 
 The Indicator, Prince Regent Mine, Ballarat. 
 
 deposition. As yet, however, the evidence does not go much 
 further than to accentuate the coincidence between the occur- 
 rence of rich gold-ore and a casing of carbonaceous rock. The 
 organic matter observed in the Indicator seam, and also in the 
 clay following the faults, is of particular interest, because it 
 agrees with similar observations made in other mining regions. 
 
 nor can the industry of mining which is based upon the application of science be 
 aided by fancies, however alluring. 
 
THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 15 
 
 The graphitic slates of the neighboring district of Bendigo ap- 
 pear to have exerted a favorable influence on the deposition of 
 gold. These, like those of Ballarat, are of Lower Silurian age, 
 but the same coincidence marks the Devonian shales of Gympie, 
 in Queensland, and the Jurassic slates of California. Small 
 patches of peculiarly beautiful crystalline gold are found in the 
 black Cretaceous shales of Farncomb hill, at Breckenridge, 
 
 SCALE OF FEET 
 
 The Metropolitan Lode. 
 
 Colorado ; and at Rico, in the same State, a series of black 
 shales and limestones of Lower Carboniferous age enclose the 
 richest portion of a very extensive series of veins. In these 
 cases the blackness represents the carbonaceous remnant of 
 vegetable matter which was mingled with the silt and slime out 
 of which the slates and shales were formed. In the case of so 
 persistent and thin a seam as the Indicator we have to suppose 
 
16 THE INDICATOR VEIN, BALLARAT, AUSTRALIA. 
 
 an extremely slow sedimentation, occurring in a large sheet of 
 water undisturbed by cross-currents. The clay of the " slides," 
 examined by Dr. Don, must have derived its carbonaceous con- 
 stituent through mechanical action upon the edges of the slate- 
 beds crossed by the line of faulting; the softer members of the 
 series being, as I remember, the blackest. 
 
 This association of gold and carbonaceous matter has been 
 investigated by Dr. Don with negative results, not only at 
 Ballarat but also at Gympie. It would appear that where the 
 black slates are gold-bearing they also carry a notable amount 
 of pyrites. This was so at Rico, where I was able to make a 
 careful study* of the veins which seemed to have been favor- 
 ably affected by a graphitic encasement. But Dr. Don was 
 looking in the enclosing rocks for the source of the gold, and 
 not for a precipitant, because he is impressed with the fact that 
 gold is so easily precipitated from its solutions that it is scarcely 
 necessary to seek for a special agent. Nevertheless} accepting 
 as I do the general theory of an ascending circulation as the 
 basis of a science of ore-deposits, it seems to me that it is for 
 the causes favoring precipitation that we must seek if we are 
 to understand the vagaries of gold-occurrence. The experi- 
 ments f made with the Rico shale illustrated the rapidity with 
 which gold is precipitated from certain solutions when they 
 come in contact with such carbonaceous matter. That there is 
 also much black slate and graphitic shale which is not remark- 
 able for containing rich gold-veins, is no particular argument 
 against the value of the observation. The carbonaceous mat- 
 ter was probably only one out of several factors which favored 
 the precipitation of the. gold ; and the pyrite, having been de- 
 posited previous to the gold, was probably another. But how- 
 ever that may be, it is an inquiry which must be left to pains- 
 taking investigators like Dr. Don, and not to mining engineers, 
 who, like the writer, have not the time or the ability for such 
 work. For us, and for the miners whom we direct, it is well 
 to emphasize the fact that certain observed conditions, struc- 
 tural or physical, are favorable to the finding of gold ; and if, 
 in our daily work, we can collect further observations of this 
 kind we shall have done something to aid the endeavors of the 
 specialists who are patiently trying to unravel the mysteries 
 which beset the genesis of ore-deposits. 
 
 * "The Enterprise Mine, Eico, Colorado," Trans., xxvi., 906. 
 
[TRANSACTIONS OF THE AMERIC\N INSTITUTE OF MINING ENGIN1 ERS.] 
 
 The Alluvial Deposits of Western Australia. 
 
 BY T. A. RICKARD, STATE GEOLOGIST, DENVER, COLORADO. 
 
 (Buffalo Meeting, October, 1898.) 
 
 I. GENERAL GEOLOGICAL CONSIDERATIONS. 
 
 THE interior of West Australia is an arid table-land, elevated 
 1400 feet above the sea. This plateau is flanked to the south 
 by the Tertiary limestones which fringe the Great Australian 
 Bight. It is bordered northward by the Carboniferous beds of 
 the Fitzroy river and westward by the granite of the Darling 
 hills, while to the east this wide area, about 900 miles square, 
 slopes downward imperceptibly into an undulating plain of 
 sand, which stretches with dismal persistence across the boun- 
 dary of South Australia. The waters of the ocean receded 
 from this tract of land long ago ; it is probably the oldest land- 
 surface on the globe, and represents the basal wreck of a much 
 larger continent. Fig. 1 is a map of this region. 
 
 The Coolgardie and Kalgoorlie gold-fields are situated in the 
 southwestern part of the region. The rock-formation consists 
 of granite penetrated by diorites and andesites. The latter are 
 occasionally associated with tuffs, which have been readily mis- 
 taken for sedimentaries. There are no fossil-bearing rocks, 
 such as would afford a datum-line from which to measure the 
 relative geological age of the prevailing formation. On the 
 extreme edges of the mining territory there are, it is true, 
 remnants of sand-rock which are considered identical with 
 the " Desert Sandstone " of Queensland, determined by Dain- 
 tree to be of Mesozoic age. But even this formation has 
 evidently been laid down so long subsequent to the underlying 
 rocks that it serves merely to emphasize their much greater 
 antiquity. 
 
 In their characteristics and in their relations to each other, 
 the granite and the diorite of the Coolgardie region appear to 
 me much to resemble the Laurentian granite and the Huronian 
 
2 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 schists of Ontario, in Canada.* Their age can only be vaguely 
 described as Archaean. 
 
 On many parts of the earth's surface a long-continued, slow 
 movement of continental uplift, interrupted by intermittent 
 periods of rest or subsidence, has permitted the transfer of land 
 to the sea by the erosion of the exposed parts and the depo- 
 sition of their detritus as ocean sediment, thus causing the up- 
 building of a mountain-system composed of a series of rocks 
 belonging to successive epochs. In this particular region, on 
 the contrary, all diversity is wanting, and a sameness of aspect 
 wearies the observer. In the absence of an elevatory move- 
 ment, more than sufficient to balance the slow degradation of 
 the higher parts of the region, there has been no compensation 
 for the effects of atmospheric erosion, so that this tract has be- 
 come a dreary flat, strewn with the sandy wreck of weathered 
 rocks. 
 
 The United States offers both a contrast and a parallel. In 
 the Rocky Mountain region the movement of uplift which com- 
 menced in pre-Cambrian times has only been interrupted so as 
 to permit of the laying-down of younger sediments ; and the 
 degradation of the high places has been compensated, and 
 sometimes exceeded, by an elevation which has resulted in the 
 formation of a mountain mass flanked by a long succession of 
 strata now enclosing a great variety of mineral wealth. The 
 interior of Australia can be likened to the Great Basin, occu- 
 pied by Nevada and parts of Utah, Idaho and Arizona, between 
 the Rocky Mountains themselves and the Sierra Nevada. There 
 is only one large river in Australia which reaches the sea, 
 namely, the Murray, which rises near the boundary-line of Vic- 
 toria and New South Wales, and then flows toward the inte- 
 rior, to be saved by a backward sweeping curve, which permits 
 the river at length to empty itself into the sea at the border of 
 South Australia. There are many " lost rivers," like the Carson 
 
 * The mass of the granite is penetrated by the mass of the diorite, the latter 
 being therefore the younger ; but puzzling evidence is, afforded by the fact that 
 the diorite at the contact is sometimes traversed by embranchments of gran te, 
 which are explainable on the supposition that subsequent metamorphism gave the 
 granite a renewed mobility, permitting it to penetrate fractures in the diorite. 
 At Rat Portage, Ontario, the overlying, younger Huronian schists are inter- 
 calated and penetiated by the older Laurentian granite at certain places along the 
 line of contact. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 FIG. 1. 
 
 WESTERN AUSTRALIA 
 
 PROCLAIMED GOLDFIELDS 
 
 REFERENCE: 
 
 Railways open for Trade 
 
 Railways under Construction 
 
 Boundaries of Gold Fields 
 Stock Routes 
 
 KMtefi o H7 . 
 
 Soutli 
 
 V \a\tF3* 
 
 AMERICAN BANK NOTE CO. NEW YORK 
 
4 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 and the Humboldt in Nevada. During the rainy season they 
 are tempestuous torrents ; during the succeeding dry months 
 their course is marked by sandy bottoms, dotted with an occa- 
 sional water-hole. The mountains are near the coast, so that 
 the Australian Alps and the Blue Mountains do the same ser- 
 vice as the Sierra Nevada and the Cascades, in that they inter- 
 rupt the warm, moisture-laden winds, and compel them to pre- 
 cipitate on the seaward slope. The consequence is that the 
 eastern parts of the colonies of Queensland, New South Wales 
 and Victoria, between the mountains and the sea, resemble the 
 valleys of California and Oregon, just as the interior region 
 beyond them bears a likeness to the dry tracts of Nevada and 
 Arizona. 
 
 The sea retired from the interior of West Australia in the 
 very dawn of geological time, and the movement of elevation, 
 which raised the land above the waters, continued with but 
 little interruption until the beginning of the Tertiary period. 
 Since then, slow subsidence has robbed the Australian conti- 
 nent of a part of its extent, and made Tasmania an island. 
 There is evidence of a much larger continental area, which at 
 one time extended toward Southern Africa. The encroachment 
 of the sea has crowded a wonderful variety of flora into the 
 small stretch of fertile country lying between the desert and 
 the Indian Ocean.* 
 
 The main drainage of the interior is to the south. The last 
 retreat of the sea was accompanied by the formation of broad 
 valleys, which have lost their former outlines, and now ap- 
 pear as long depressions, largely filled up with the products 
 of erosion. 
 
 II. THE PHYSIOGRAPHY OF THE GOLD-FIELDS. 
 
 The principal gold-field of West Australia is situated in the 
 southwestern part of the desert plateau. The chief towns are 
 
 * This corner of Australia is celebrated among botanists for the extraordinary 
 variety of its flora. Baron Ferdinand von Mueller, the celebrated botanist, may 
 be quoted : " A marvellous exuberance of plants, different in species, and often 
 gay or odd in aspect, exists within a triangle formed by a line of demarkation 
 drawn from the south of Sharks Bay to the west of the Great Bight ; and within 
 this space are chiefly located those species which are exclusively restricted to West 
 Australian territorv." 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 5 
 
 Coolgardie and Kalgoorlie.* They are connected by 350 miles 
 of railway with the coast During the year 1897 the total rain- 
 fall amounted to 5f inches at the one place and 4| inches at 
 the other, f In contrast to these figures, it may be added that 
 the rate of evaporation in this region is estimated to be equiva- 
 lent to 7 feet per annum. 
 
 The country consists of a sandy plain, the monotony of which 
 is intensified by a series of alternating low rocky ridges and 
 equally slight depressions, having a northwesterly direction. 
 Most maps indicate the occurrence of lakes and the occasional 
 course of a stream, but these are the mirages of the cartog- 
 rapher. The " lakes " are shallow basins with clay bottoms, in 
 which, during the rainy season, a little water lingers, and the 
 " streams " are sandy channels, where sinking will sometimes 
 tap a trickling flow of brine. 
 
 The surface is devoid of vegetation, except in spring, when 
 flowersj of a brilliant hue, but with the texture of hay, leap 
 into brief existence. Animal life is infrequent. An occasional 
 bustard may be provoked into leisurely flight, a troop of paro- 
 quets throws a momentary gleam athwart the dull gray of the 
 bush, or a solitary kangaroo hops across the trail. These, how- 
 ever, are but infrequent interruptions to the sullen silence of 
 the wilderness. 
 
 The real nakedness of the region is hidden by the " bush," 
 consisting of scrub from 20 to 60 feet high, chiefly mulga and 
 ti-tree. This covers all things as with a garment (see Fig. 2). 
 The roads are cut through it with the monotonous regularity 
 of a canal. One portion ot the journey is but the counterpart 
 of another. The sameness is wearisome beyond words. And 
 
 * These localities are not found save on recent maps. Kalgoorl'e is in latitude 
 3 J 4V south and longitude 121 30' east, while Coolgardie lies in latitude 30 57' 
 south and longitude 121 10' east. They are 25 miles apart. 
 
 t The rainfall at Denver is 14 ; Alexandria, 10 ; Paris, 22 ; London, 35 ; 
 Canton, 39 ; Calcutta, 76; Vera Cruz, 180; and at Cherrapongee, in Assam, 610 
 inches per annum. 
 
 J The " Everlastings," as they are usually called, belong chiefly to the genera 
 Helichrysum, Helipterum, "NVaitzia, Podolepis and Angianthus. For about three 
 months they appear as magnificent splashes of color, carpeting the desert with 
 splendor. They are wholly devoid of perfume, and have the brittle texture of 
 artificial flowers. 
 
 \ Both acacias. The characteristic tree-shrubs of the country belong to the 
 genus Acacia. Many of them have a fragrant bloom in the spring. 
 
6 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 when an elevated spot is attained the eye commands, from 
 north to south, from east to west, one dark unbroken sea of 
 trackless hush. 
 
 Gold-mining caused this desert to be invaded. The first dis- 
 covery was made by Anstey, in 1887, at Yilgarn, which is 210 
 miles east from Perth, the capital of the colony. This started 
 the Southern Cross mining district. Prospectors began to 
 scatter further inland. In 1892 Bayley made the discovery 
 which marked the birth of Coolgardie, and the commencement 
 of an activity which culminated in the mining excitement of 
 1895. A series of rich finds, scattered over the surrounding 
 desert, gave rise to the settlements of Menzies, Goongarrie, 
 Kanowna, Kurnalpi, Kunanalling, "Wagiemoola, and a score of 
 other patches of corrugated-iron hideousness labeled with 
 euphonious aboriginal names. In June, 1893, Patrick Hannan 
 pegged out a discovery-claim at Kalgoorlie,* 25 miles east of 
 Coolgardie. The find which he made was of no particular im- 
 portance, and the neighboring area, like many others, became 
 the scene of the purposeless digging which was at that time 
 sufficient to give an impetus to a great deal of reckless com- 
 pany-promoting. However, just as, in Colorado, the Mt. Pisgah 
 fiasco of 1884 preceded the real development, eight years later, 
 of Cripple Creek, so the vagaries of irresponsible schemers led 
 to the accidental opening up and the eventual recognition of the 
 magnificent series of rich lodes that have now placed Kalgoorlie 
 among the few great mining camps of the globe. 
 
 In 1897 West Australia produced 674,993 ounces of gold, to 
 which Kalgoorlie alone contributed 306,000 ounces. During 
 the same period the mines of the colony paid $2,400,420 in 
 dividends, and out of this total Kalgoorlie is credited with 
 $1,775,000. The growth of the industry is exhibited by the 
 accompanying statistics : 
 
 Kalgoorlie. West Australia. 
 Year. Ounces. Ounces. 
 
 1895, . . ; . . . . 36,000 231,513 
 
 1896, . . .... . . 103,000 281,265 
 
 1897,. * . .... 306,000 674,993 
 
 It is estimated that the yield of the colony for the current 
 
 * See the interesting paper of my friend, Mr. George J. Bancroft, ' ' Kalgoorlie, 
 Western Australia, and Its Surroundings," read at the Atlantic City Meeting, 
 February, 1898. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 7 
 
 year will reach a million ounces, and that of this one-half will 
 come from the Kalgoorlie district. 
 
 The development of a group of very rich telluride lodes amid 
 this immense desert country, dotted over with the unhappy 
 failures which were based on small pockets of specimen gold- 
 quartz, did not happen without a sad expenditure of money and 
 human life. "With the whisper of every new discovery, crowds 
 of reckless gold-seekers plunged madly into the outer desolation. 
 Eager horsemen jostled the awkward camels, whose swinging 
 gait carried them in turn past the mohs of diggers who trudged 
 wearily to the scene of each successive excitement. One knows 
 not whether to admire the pluck or to deride the foolishness of 
 men who died of thirst and perished of fever in the mad search 
 for gold. The incident known as " the Siberia rush " will be 
 typical of early days. A man came into Coolgardie one night 
 with a story that gold had been found at a locality thirty-odd 
 miles to the north. Hundreds started off on horses or on 
 camels ; many went on foot, carrying their billies* and blankets 
 upon their shoulders or trundling their packs in wheelbarrows. 
 Some took the wrong direction, and of these many never 
 reached their destination, but died miserably in the bush. 
 Four hundred eventually reached Siberia, f The only water 
 near the discovery was a soak,| seven miles distant. It was 
 soon drained dry by the crowd of diggers, l^ews came to 
 Coolgardie that a water-famine was imminent. The superin- 
 tendent of water-works, a government officer, instantly de- 
 spatched a dozen camels to the succor of the adventurers. In 
 the meantime, they, realizing the impending danger, had left 
 the gold, and were making for the nearest condenser. || Many 
 died on that return journey, and many more would have been 
 lost save for the water brought by the camel-train. But in a 
 few days there was another stampede in another direction. 
 Thus the gold-fields were opened up. Sic Etruria crevit. 
 
 * The "billy" is the tinned-iron vessel, of from 2- to 4- quart capacity, in 
 which the miner makes his tea and does his cooking. 
 
 f What a satire is the name ! The locality has a mean annual temperature of 
 78, and the summer heat is 112 to 120 in the shade. 
 
 | A "soak" is the morass of the desert, where water has accumulated in a de- 
 pression, and is got by digging through the sand which covers it. 
 
 % A camel carries two tins, each holding '10 gallons. 
 
 || All the drinking-water is the product of the ''condenser," of which a de- 
 scription is given below. See Figs. 3, 4, 24, and 25. 
 
8 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 The peculiar character of these " rushes " is directly traceable 
 to the nature of the gold-occurrence. Gold is found lying on 
 the very top of the ground, and the first surface-mining yields 
 extraordinary profits. The search for the particles of gold 
 scattered over the surface is called u specking." In the early 
 days hundreds of ounces were thus picked up in a few hours 
 by the men first to reach a rich spot. When the cream has 
 thus been skimmed off, the sandy soil underneath is treated, 
 the dirt being winnowed by pouring it from one pan into 
 another. After that, actual digging begins, the shallow deposits 
 being trenched and pitted in the search for those patches of 
 rich ground through which the gold is found sporadically dis- 
 tributed. " Specking " is still a recognized occupation on 
 Sundays,* even at the established mining centers. I have seen 
 as many as a hundred men walking about with their hands in 
 their pockets and their eyes intent on the ground, for all the 
 world as if they were in disgrace. A five-ounce nugget may 
 be found ; and everyone hastens to the spot. Perhaps nothing 
 more is picked up; or it may be that sufficient gold is dis- 
 covered to attract troops of " dry-blowers" to the place. The 
 " dry-blower " is brother to the " gulch-miner " of America 
 and the " alluvial digger " of the eastern colonies of Australia. 
 In the investigation of the methods of the dry-blower and the 
 occurrence of the deposits out of which he wins the gold, I 
 observed many facts of such interest, it seemed to me, as to 
 warrant the preparation of this contribution to the Transactions 
 of our Institute. 
 
 In mountainous regions the disintegration of the surface is 
 mainly caused by the frost. Water penetrates into crevices 
 and cracks, and, because its maximum density is at 4 C. and 
 not at zero, it undergoes such expansion in the immediate ap- 
 proach to the freezing-point as to become a powerful lever for 
 tearing the rocks apart. Thus is loosened that material out of 
 which eventually the alluvial deposits of the valley are formed. 
 In warmer climates the contraction and expansion of water is 
 likewise a ceaselessly destructive agent. Even in a dry, hot, 
 region, such as the interior of West Australia, the difference 
 
 * Sunday labor is generally forbidden throughout the Australian colonies ; hence 
 the opportunity to go "specking," as above described. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 9 
 
 between the heat of day and the cold of night causes the dew 
 to play an important part in moulding the physiography of the 
 country. For it must be remembered that the changes of 
 volume caused, in water as in other substances, by changes of 
 temperature, are well-nigh irresistible in energy, however minute 
 in amount. The cool nights, which alone make life bearable 
 on the Coolgardie gold-fields, are thus beneficent in two ways. 
 To them is ultimately owing the formation of those accumula- 
 tions of gold-bearing dirt out of which many a prospector has 
 dug himself a competence for life. The tables on page 10 from 
 the government meteorological reports exhibit this variation 
 in temperature. 
 
 In mountainous lands the melting of the winter snows yields 
 the water employed in that process of concentration which 
 begins as soon as the rock is shattered, and continues until 
 each ultimate particle has been classified by the untiring ma- 
 chinery of nature. The " tailings " are the mud and sand \vhich 
 go to build new continents upon the ocean-floor, the " mid- 
 dlings " are the great masses of alluvium covering the plain, 
 and the " heads " are the gold-bearing gravels of the mountain- 
 valley. The soft is separated from the hard, the heavy from 
 the light, until at length the metal once incased in quartz and 
 enclosed within the rock is set free, to be collected wherever 
 the eager stream has so abated its force as to permit the parti- 
 cles of gold to find a quiet resting-place. 
 
 It is a great sifting-process. The motion of the water is gov- 
 erned by the slope of the surface. In a flat country the condi- 
 tions resemble those surrounding a mill so situated as to be in- 
 capable of getting rid of its accumulating tailings. Should the 
 water-supply of the mill also prove insufficient to carry out its 
 operations, then the analogy with a desert plateau is complete. 
 The process of concentration must in both cases remain un- 
 finished. 
 
 The gold-bearing gravels of California and Victoria, for 
 example, usually rest on a hard bed-rock, whose water-worn 
 surface speaks of the agency which made it so. The particles 
 of gold and heavy iron-sand have been washed clean ; the over- 
 lying pebbles and quartz gravel are comparatively free from 
 material less resisting than themselves ; and, if there be any clay, 
 it is found in distinct layers, in positions testifying to the varia- 
 
10 
 
 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 TABLE I. Meteorological Conditions at Coolgardie, 1897. 
 
 
 TEMPERATURE. 
 
 TEMPERATURE 
 OP DEW-POINT. 
 
 RAINFALL. 
 
 Month. 
 
 Mean 
 Max. 
 
 Mean 
 Min. 
 
 Highest 
 Max. 
 
 Lowest 
 Min. 
 
 Greatest 
 Variation 
 in One Day. 
 
 Mean. 
 
 9A.M. 3P.M. 
 
 Total 
 Inches. 
 
 Days. 
 
 
 
 
 
 
 
 
 o 
 
 
 
 
 
 o 
 
 
 
 January 
 
 94.1 
 
 63.2 
 
 104.3 
 
 53.0 
 
 42.2 
 
 53.5 
 
 54.0 
 
 .56 
 
 4 
 
 February... 
 
 89.4 
 
 58.5 
 
 104.6 
 
 47.4 
 
 47.3 
 
 51.8 
 
 53.6 
 
 .54 
 
 5 
 
 March 
 
 85.6 
 
 57.7 
 
 98.4 
 
 50.0 
 
 41.0 
 
 49.2 
 
 55.0 
 
 .10 
 
 2 
 
 April 
 
 81 2 
 
 53 9 
 
 96 1 
 
 39 1 
 
 36 5 
 
 51 3 
 
 57 4 
 
 01 
 
 ^ 
 
 May 
 
 71.4 
 
 46.6 
 
 88.4 
 
 38.2 
 
 41.5 
 
 46.9 
 
 53.5 
 
 .09 
 
 3 
 
 June ... . 
 
 62 9 
 
 43 9 
 
 71 2 
 
 31 5 
 
 09 g 
 
 44 2 
 
 49 7 
 
 1 04 
 
 g 
 
 July 
 
 65.1 
 
 42.4 
 
 74.0 
 
 36 5 
 
 33 5 
 
 43 5 
 
 47 5 
 
 34 
 
 g 
 
 August 
 
 63.8 
 
 41.5 
 
 81.0 
 
 33.0 
 
 34.6 
 
 40.8 
 
 43.7 
 
 1.08 
 
 10 
 
 September- 
 
 75.0 
 
 47.5 
 
 92.0 
 
 35.0 
 
 39.7 
 
 43.7 
 
 49.5 
 
 .29 
 
 6 
 
 October 
 
 81.0 
 
 49.8 
 
 91.0 
 
 41.0 
 
 39.7 
 
 
 
 .06 
 
 2 
 
 November- 
 
 90.6 
 
 58.4 
 
 105.0 
 
 47.3 
 
 44 6 
 
 
 
 09 
 
 1 
 
 December.. 
 
 91.7 
 
 59.5 
 
 109.2 
 
 ft! 
 
 44 9 
 
 
 
 1 31 
 
 4 
 
 
 
 1898. 
 
 
 
 
 
 January I 97.6 
 
 65.1 
 
 111.2 
 
 64.0 
 
 43.2 
 
 60.1 
 
 68.2 
 
 Nil. 
 
 
 February... 89.3 
 
 62.5 
 
 107.2 
 
 48.0 
 
 37.7 
 
 57.0 
 
 60.2 
 
 .27 
 
 1 
 
 TABLE II. Meteorological Conditions at Kalgoorlie, 1897. 
 
 
 TEMPERATURE. 
 
 TEMPERATURE 
 OF DEW-POINT. 
 
 RAINFALL. 
 
 Month. 
 
 Mean 
 Max. 
 
 Mean 
 Min. 
 
 Highest 
 Max. 
 
 Lowest 
 Min. 
 
 Greatest 
 Variation 
 in One Day. 
 
 Mean. 
 
 9A.M. 3P.M. 
 
 Total 
 Inches. 
 
 Days. 
 
 
 o 
 
 , 
 
 
 
 
 
 o 
 
 
 
 Q 
 
 
 
 January 
 
 92.9 
 
 66.0 
 
 105.0 
 
 55.0 
 
 34.2 
 
 51.1 
 
 52.0 
 
 .38 
 
 2 
 
 February- 
 
 88.2 
 
 61.6 
 
 103.0 
 
 49.0 
 
 34.7 
 
 51.2 
 
 51.5 
 
 .02 
 
 1 
 
 March 
 
 83.8 
 
 58.9 
 
 98.4 
 
 51.0 
 
 39.0 
 
 49.0 
 
 49.4 
 
 .52 
 
 6 
 
 April 
 
 80.0 
 
 55.9 
 
 95.4 
 
 38.8 
 
 K2.8 
 
 48.0 
 
 46.8 
 
 .20 
 
 1 
 
 May 
 
 69.8 
 
 48.0 
 
 88.1 
 
 37.0 
 
 40.4 
 
 46.5 
 
 45.0 
 
 .10 
 
 1 
 
 June 
 
 62.9 
 
 47.4 
 
 73.2 
 
 36.2 
 
 30.2 
 
 46.4 
 
 49.1 
 
 1.26 
 
 14 
 
 July 
 
 64.4 
 
 43.3 
 
 74.0 
 
 33.2 
 
 29.8 
 
 42.8 
 
 43.7 
 
 
 3 
 
 August 
 
 63.8 
 
 43.3 
 
 82.0 
 
 34.0 
 
 29.1 
 
 40.0 
 
 41.7 
 
 '65 
 
 9 
 
 September. 
 
 74.2 
 
 48.8 
 
 90.8 
 
 37.2 
 
 40.2 
 
 41.6 
 
 43.8 
 
 !41 
 
 5 
 
 October 
 
 78.5 
 
 51.8 
 
 90.2 
 
 41.0 
 
 38.0 
 
 42.0 
 
 40.4 
 
 .11 
 
 2 
 
 November- 
 
 90.2 
 
 59.0 
 
 103.0 
 
 48.0 
 
 49.0 
 
 46.8 
 
 48.7 
 
 .06 
 
 1 
 
 December.. 
 
 90.7 
 
 61.6 
 
 109.2 
 
 49.4 
 
 39.0 
 
 48.3 
 
 49.5 
 
 .82 
 
 4 
 
 1898. 
 
 January 
 
 98.0 
 
 66.8 
 
 113.2 
 
 55.0 
 
 41.0 
 
 51.3 
 
 50.3 
 
 .02 
 
 1 
 
 February... 
 
 90.5 
 
 63.4 
 
 109.8 
 
 48.2 
 
 38.6 
 
 51.2 
 
 49.9 
 
 .36 
 
 3 
 
 tions in the velocity and volume of the stream which laid down 
 the deposit as a whole. It is an orderly arrangement of assorted 
 material. 
 
 Compare with this the alluvium of the desert. A low ridge 
 is crested with the outcrop of a gold-bearing quartz-vein which, 
 amid that surrounding sea of dark-blue scrub, justifies its colo- 
 nial designation, a "reef." On its flanks there is a thin cover of 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 11 
 
 sandy soil which gradually thickens, a little lower down the 
 slope, to a deposit of several feet. Sink a hole and you will 
 find, first an inch or two of loose sand and dust, then a more 
 solid layer of gravel and dirt, which in turn passes imperceptibly 
 into a compact material consisting of fragments of rock and 
 quartz, held firmly together by clay. It is called " cement," 
 and it might better be termed an " agglomerate." It is an un- 
 classified product of erosion, and lies close to the place of its 
 origin, as a mere collection of unsorted debris. 
 
 The rock on which the deposit rests is so softened by decom- 
 position that it is frequently taken for a part of the overlying 
 detritus. If the hole be continued so as to become a well or 
 shaft, it will penetrate through additional oxidized ground until 
 this suddenly gives place to diorite or granite (the two prevail- 
 ing formations) at a depth varying from 75 to 200 feet, which 
 is the drainage-level of the region. 
 
 This deposit owes its existence to the wind and rain, assisted 
 by gravity acting on a slightly inclined surface. Wind is ordi- 
 narily an insignificant geological agent, but in the constant and 
 violent draughts of a high plateau there is a force which, work- 
 ing during long periods of time, is capable of producing notable 
 results. In the vicinity of Coolgardie and Kalgoorlie, espe- 
 cially the latter, which has the less broken topography, the 
 dust-storms are almost ceaseless, and bear forceful testimony to 
 the amount of material which can be conveyed in the air. The 
 wind careers over the country in gyrating whirls, to which the 
 aborigines give the name of " willy-willy," nor have the white 
 invaders ventured to call them otherwise ; and as these whirl- 
 winds go waltzing across the wretched town, they gather up in 
 their skirts all the scattered refuse of a border civilization. I 
 formed the impression that the wind had a prevailing direction 
 from the southeast to the northwest, that is, from the nearest 
 sea toward the heated interior; but the meteorological re- 
 ports of the government do not confirm this supposition. In 
 the accompanying table, Beaufort's scale of wind-force is em- 
 ployed. It will be observed that the meteorological reports 
 confirm the impression that Kalgoorlie is more windy than 
 Coolgardie, and that a quiet condition of the atmosphere is un- 
 usual in both districts. Nor is there any consistency of direc- 
 tion, as is proved by the observations made, for example, at 
 
12 
 
 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 Kalgoorlie during the month of September, 1897. It is evi- 
 dent that the wind blew where it listed, and no man could tell 
 whence it came. The following is Beaufort's scale of wind- 
 force : 
 
 Speed of wind 
 Number. ' Description. in miles per hour. 
 
 Calm. 3 
 
 1 Light air. 8 
 
 2 Light breeze. 13 
 
 3 Gentle breeze. 18 
 
 4 Moderate breeze. 23 
 
 5 Fre-h breeze. 28 
 
 6 Strong breeze. 34 
 
 7 Moderate gale. 40 
 
 8 Fresh gale. 48 
 
 9 Strong gale. 56 
 
 10 Whole gale. 65 
 
 11 Storm. 75 
 
 12 Hurricane. 90 
 
 TABLE ILL Wind-Force, 1897. 
 
 Month. 
 
 COOLGARDIE. 
 
 KALGOORLIE. 
 
 9 A.M. 
 
 Max. Min. 
 
 3P.M. 
 Max. Min. 
 
 9 A.M. 
 
 Max. Min. 
 
 3 P.M. 
 Max. Min. 
 
 January 
 
 3 
 4 
 3 
 
 4 
 8 
 2 
 5 
 5 
 9 
 5 
 6 
 9 
 
 1 
 2 
 2 
 
 
 2 
 1 
 
 1 
 
 3 
 4 
 3 
 3 
 3 
 3 
 6 
 6 
 9 
 8 
 9 
 4 
 
 
 1 
 
 1 
 2 
 
 2 
 1 
 1 
 1 
 1 
 1 
 1 
 
 2 
 7 
 5 
 
 2 
 5 
 9 
 3 
 6 
 6 
 7 
 5 
 2 
 
 1 
 
 2 
 2 
 1 
 2 
 2 
 2 
 2 
 
 2 
 2 
 2 
 2 
 
 3 
 
 7 
 2 
 9 
 2 
 5 
 4 
 8 
 9 
 6 
 8 
 3 
 
 3 
 2 
 
 
 1 
 
 2 
 
 2 
 
 2 
 2 
 2 
 2 
 2 
 2 
 
 February 
 
 March 
 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September . 
 
 October 
 
 November . 
 
 December 
 
 
 TABLE IV. Variation in Direction of the Wind at 
 Kalgoorlie during September , 1897. 
 
 9 A.M. 
 
 Direction of wind. 
 
 N. 
 
 N. to E. 
 
 E. 
 S. to E. 
 
 S. 
 S. to W. 
 
 w. 
 
 N. to W. 
 
 Days. 
 4 
 
 5 
 3 
 5 
 1 
 6 
 1 
 2 
 
 3 P.M. 
 
 Direction of wind. Days. 
 4 
 
 N. 
 N. to E. 
 
 E. 
 S. to E. 
 
 S. 
 S. to W. 
 
 w. 
 
 N. to W. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 13 
 
 Observations such as have been quoted in Tables III. and IV. 
 necessarily fail to record the really characteristic play of the 
 wind in this region. The whirl-storms, referred to already, 
 spring up suddenly, rush madly across the plain, suck up every- 
 thing lying loose on the surface, arid as suddenly subside. 
 These apparently erratic air-disturbances are responsible for the 
 transport of the greater part of the material which weathering 
 and erosion have disintegrated. So far as I know, measure- 
 ments of the transporting-power of the wind have not been made 
 in this particular region ; but elsewhere in Australia scattered 
 observations have been made ; for example, that fences 4 feet 
 high are buried by drifting sand in a period only slightly ex- 
 ceeding two years. In the Libyan desert, bordering the Kile 
 valley, the same results can be seen. Thus, for instance, the 
 sand-storms bury the temple of the Sphinx every summer, and 
 the road built by Ismail Pasha, from the Mena House to the 
 Pyramids, is filled with sand up to the level of the 6-foot para- 
 pet in less than ten days.* 
 
 In West Australia there is much evidence of that which 
 geologists euphuistically term the ^Eolian agency. The wind 
 has been stirring and sifting the material lying loose on the 
 surface until it has become classified to a remarkable degree. 
 In traveling over the country, one is soon called upon to notice 
 the broken white quartz scattered over the ground, in big 
 patches many acres wide. These alternate with stretches, 
 steel-gray in the morning and blue-black toward the close of 
 day, of ironstone fragments. Leave the trail ; go a short distance 
 into the bush ; and you will find the surface covered with dust 
 in which each step leaves an evident footprint. It is the veri- 
 table dust of ages, not the earth-smoke blown from man's restless 
 to-and-fro. The wind has sorted the quartz, the ironstone 
 and the dust. The latter has been scattered in contemptuous 
 carelessness all over the face of the weary desolation, but the 
 heavy ironstone remains not far from where it was broken off 
 the decomposing diorite until, shattered and comminuted to 
 powder, it also is winnowed by the dust-storm. The numerous 
 veins, large and small, traversing the country have contributed 
 the quartz which the wind has collected, so that it sometimes 
 covers the ground with the glittering whiteness of a snow-drift. 
 
 * So my dragoman informed me when I was there last February. 
 
14 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 From these stretches of ironstone and quartz one would 
 naturally infer the occurrence, somewhere underneath the 
 surface, of large masses of both. Owing to the extreme slow- 
 ness with which denudation progresses in this arid region, and 
 the consequent very gradual lowering of the zone of oxida- 
 tion, the rocks exhibit, above the drainage-level, a marked in- 
 tensity of chemical action. The granite is kaolinized to an 
 almost incoherent clay, and the diorite is rendered abnormally 
 heavy in iron by the surface-concentration of decomposition-prod- 
 ucts. And, as the rock is eroded, the quartz, on account of its 
 hardness, persists, so that a series of small stringers eventually 
 yields an accumulation suggestive of its derivation from a large 
 mass. It is a process of concentration which, there is reason to 
 believe, has also affected the gold-occurrence, the upper por- 
 tions of veins being enriched by the deposition of the gold left 
 behind from lode-matter which was long ago disintegrated and 
 removed by erosion. 
 
 If we now turn to the " dry-blower " and watch him at his 
 work we shall see the same processes utilized in the winnowing 
 of the gold. 
 
 III. DRY-BLOWING. 
 
 In West Australia the absence of running water renders un- 
 available the cradle and the sluice-box of ordinary placer- 
 mining, with the result that the prospector has learnt, intui- 
 tively, to utilize the agency which he sees incessantly at work 
 in the nature around him. Wind replaces water. The method 
 is simple. Taking two pans,* he places one of them on the 
 ground, empty, while into the other he puts a shovelful of the 
 " dirt," that is, the sandy detritus containing the gold. The 
 material is shaken up so as to bring the big lumps on top, and 
 then, resting the pan on one knee and holding it with his left 
 hand he uses the right hand to skim off the coarse particles (as 
 shown in Fig. 5). Then standing erect and facing at right angles 
 to the direction of the wind, he slowly empties the full pan into 
 the empty one at his feet (see Fig. 6). As the stream of dry 
 dirt falls, the wind selects the fine and blows it in a cloud of 
 dust to leeward. The operation is then reversed, the pan 
 which has just been emptied being placed on the ground so as 
 
 * The Australian calls them u dishes. 1 ' 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 15 
 
 to receive the contents of the other. This is repeated three or 
 four times, according to the degree of concentration effected. 
 In a strong breeze one operation may prove sufficient. To pre- 
 vent the loss of the fine gold which is sometimes carried away 
 with the dust it is customary to spread a piece of canvas on the 
 ground, one end being placed under the pan and the other ex- 
 tending to leeward.* The next stage is to further winnow the 
 material by tossing it up and down in the pan (see Fig. 7) ; 
 the latter is held slanting forward, and is jerked so as to throw 
 the dirt from the front to the back of the pan. The light 
 particles are separated, as chaff is driven from grain. Then, 
 giving the dish a vanning movement, the prospector again re- 
 moves the coarser particles that come to the surface by skim- 
 ming them off with his hand. There now remains about half 
 a pint of material, and this is diminished by panning, just as 
 in water, the dry particles having a mobility permitting this 
 method of treatment. Finally he drops on his knee, and, hold- 
 ing the pan (see Fig. 8) so that it is tilted forward, he raises 
 it up to his mouth and uses the breath of his lungs to complete 
 the process. The particles of gold are seen fringing the edge 
 of the iron sand. If the yield consist of only a few minute par- 
 ticles,f he puts his moist thumb on them, and so transfers them 
 to his pocket; but if there be any coarse pieces nuggets 
 they are put into the leather wallet attached to his belt. 
 
 In watching a dry-blower at work, it becomes evident 
 that the operation, like every process of concentration when 
 properly conducted, consists of sizing and classification. The 
 wind removes the fine sand and the dust, the operator's hand 
 skims off the larger lumps of dirt, so that there finally remains 
 a collection of those heavy particles of ironstone which, as in 
 ordinary placer-mining, accompany the gold. 
 
 Owing to the perfect dryness of the dirt and the heat im- 
 parted to the surface of the iron pan under a tropical sun, the 
 material behaves with much of the mobility which it would 
 have if water and not air were the vehicle employed. It re- 
 minds one of the behavior of a charge in the roasting-furnace, 
 in which the hot air cushions each particle so as to give to the 
 mass an apparent fluidity. 
 
 * As illustrated in the Figs. 5, 6, 7, and 8. These were reproduced by Mr. 
 Henry Keed, of Denver, from photographs taken by me at Kalgoorlie. 
 f " A few small colors," as we would put it in the United States. 
 
16 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 The rapidity and completeness of the operation depend on 
 the strength and uniformity of the wind. There is a constant 
 light breeze on the gold-fields, even during those happy inter- 
 vals when the dust-whirls have temporarily subsided ; but the 
 cloudy mornings of the wet season and the sultry days of the 
 hottest summer months are alike unfavorable to dry-blowing, 
 because at such times the air is dead. Many of the mining- 
 camps are situated on a slight rise of ground, overlooking those 
 desolate sinks of salt and sand which are called "lakes;" and 
 the difference of level is marked by a constant breeze which is 
 a good friend to the dry-blower. 
 
 In the history of ordinary alluvial mining, washing with the 
 pan was succeeded by the use of the sluice-box and the cradle. 
 Similarly the " dishes " of the dry-blower are replaced by ma- 
 chine's of several types, all of which, however, are based on the 
 idea of a shaking movement in the presence of a current of air. 
 The simplest contrivance is represented in Fig. 9. This machine 
 is 2 feet wide and 4 feet long. A is a hopper with a sheet-iron 
 bottom punched with 1-inch holes, B is a 12-mesh screen, C is 
 an 18-mesh screen, and D is the final product of the operation. 
 The dry-blower empties a shovelful of dirt into the hopper, 
 places his hands on the two sides of the machine and shakes it 
 from side to* side. There is sufficient play in the frame itself 
 to permit a movement which causes the material to pass 
 through the series "of screens and accumulate underneath. It 
 is then treated by hand, as previously described and illustrated. 
 One man will put through about 5 tons of loose dirt in a work- 
 ing-day of seven hours. 
 
 Another and more elaborate contrivance is exhibited in Fig. 
 10. It consists of a series of four trays, hung on a triangular 
 frame, B C D. The trays are 22 inches in diameter. They are 
 comparatively flat and have screen-bottoms, through the center 
 of which an iron rod passes to the eccentric, G, which receives 
 the required movement through the lever A E F, of which A is 
 the handle. The trays are 5 inches apart and are held in place 
 by wires, H H. The material to be treated is placed in the 
 uppermost tray, which is a hopper pierced with inch-holes. 
 No. 2 has f holes, No. 3 has a 10-mesh screen and No. 4 has 
 an 18-mesh screen. The lowest, No. 5, is flat and serves as a 
 receptacle for the final product, which is dry-blown by hand, as 
 heretofore described. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 17 
 
18 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA, 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 19 
 
20 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 FIG. 5. 
 
 Dry-blower at Work. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 21 
 
 FIG. 6. 
 
 Dry-blower at Work. 
 
22 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 FIG. 7. 
 
 Drv blower at Work. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 23 
 
 FIG. 8. 
 
 Drv-blower at Work. 
 
24 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 FIG. 9. 
 
 !*& 
 
 DRY BLOWING MACHINE 
 
 DRY BLOWING MACHINE 
 
 PLAN OF TRAY 
 
THE ALLUVIAL DEPOSITS OF WESTERN AtJSTRALlA. 25 
 
 
 - 
 
 
26 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 FIG. 12. 
 
 DRY BLOWERS AT WORK 
 
 FIG. 13. 
 
 Lorden's Dry -blowing Machine. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 27 
 
28 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 29 
 
 
 4 
 
 
 4- -- + pnn irrn 
 " 1 " "*" N b-J 
 
 + 4 1 
 
 + 4- + Q 
 
30 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 FIG. 18. 
 
 Horiz.ontal Plane 
 
 4 6 8 10 12 14 16 18 'A> 
 
 CEMENT DEPOSIT, KINTORE, WEST AUSTRALIA 
 FlO. 19. 
 
 Shaft Shaft 
 
 Longitudinal Section 
 
 Hole Shaft Shaft 
 
 THE CEMENT DEPOSIT AT KANOWNA 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 31 
 
 CO 
 
 XX 
 
 " 
 
 a 
 
 3 -3 
 
 
 
 s I 
 
 o 
 
 c 
 
 ^ '= 
 
 
 ".io. '. *"* J ...... ...*. 
 
 - 
 
 v:^ f ^">-X :: ; ^- -; ^. ^<^ 
 
 
 
 S* 
 
 o g 
 
32 
 
 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 I 
 
 
 *.;..::::' 'V ' **' ^,- Vl ^' ') ~~ 
 
 ^sl^(^ ^-^^^s 
 
 li^-:S^^^i^}^.^ 
 
 ../. :..:.:! .-.i . o ' .. --0 .' A . .* '.-'I d v v 
 
 ^^^^^^^/^ x 
 
 ^V^^5^':^^-^-^VS^ X *^<* 
 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 33 
 
 In these two contrivances no attempt is made to supple- 
 ment the wind by an artificial air-current. The next step is 
 to use a bellows. Fig. 11 shows such an arrangement. It 
 consists of a hopper A and a series of screens, B, E, F, G and 
 H. By turning the handle M the disk K is revolved; and this, 
 by means of a belt, transmits its movement to the pulley, which 
 shakes the screen B B through the eccentric-rod C, and at the 
 same time operates the bellows D through the disk K. Fig. 12 
 illustrates the machine when in operation. 
 
 When the material is placed in the hopper A and the ma- 
 chine is set in motion, the large lumps run off over the grizzly 
 or sizing-screen B B, the upper part of which is made of par- 
 allel wires ^-inch apart, and the lower portion of 8-mesh. The 
 finer stuff falls down into the shoots C C and E E, respectively, 
 and reaches F, which is another (12-mesh) screen, supplied also 
 with riffles. As it descends through the screens at G and H, 
 both 1 8-mesh, the blast from the bellows keeps the material in 
 agitation, and aids the requisite separation between the particles 
 of gold and the dust. The final product is panned by hand. 
 
 One of the most popular dry-blowing machines is that made 
 by Steve Lorden, at Freeman tie. It is illustrated in Fig. 13. 
 The essential parts are : 
 
 A. Feed-hopper, sheet-iron bottom, punched with inch-holes, 
 hinged at A 2 and provided with riffles A 3 , which arrest the 
 heavier particles of gold, while the coarse lumps of dirt pass out 
 of the machine over the shoot B 2 and the fine stuff falls through 
 into 
 
 B. Second hopper, which has riffles and smaller perforations, 
 repeating the process. To examine this hopper, the upper one, 
 A, is sprung out of position at A 4 . 
 
 C. C. Return-shoots which lead the reduced material for fur- 
 ther sizing upon the sloping screen E, which also has a series of 
 riffles, and is placed directly over the air-chamber F. 
 
 D 2 is a discharge-shoot for the screen E. G, G are air-chan- 
 nels from the bellows H, H. 
 
 H, H. Double blast-bellows, one on each side, which ride on 
 carriers H 2 , so arranged as to give the requisite play and to re- 
 lieve the bellows from undue strain when in operation. 
 
 I, I. Rockers, bolted firmly to two foundation-blocks, Lj, 
 which form the stand, the only part of the machine that is not 
 
 3 
 
34 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 in motion. The curve of the rockers allows all dirt to fall away 
 from the pivot-pins J, J, by which the apparatus swings. 
 
 K, K. Standards, hinged at L, so that the machine folds 
 up, as shown in Fig. 14. 
 
 M, M. Brackets for the insertion of two poles, by means of 
 which a couple of men can carry the machine conveniently. 
 
 The operator holds one handle, at A 4 , in each hand and 
 rocks the machine, this serving simultaneously to put the bel- 
 lows, hopper and screens all into movement. The machine 
 weighs 124 pounds and has a capacity of from 10 to 14 loads 
 (a load is roughly one ton) per day. The price at Freemantle 
 is 16 or about $80. 
 
 The deposits exploited by the aid of these machines (see Fig. 
 15) are of a generally patchy character and lie at the upper 
 ends of the depressions formed where the surface slopes away 
 from ridges traversed by the veins of gold-bearing quartz. 
 The prospector has an eye for the contour of the ground, and 
 looks for the point where the rock-surface disappears under the 
 fragmentary overburden which he calls " made ground " as dis- 
 tinguished from the underlying " bed-rock." In his search he 
 is usually guided by seeing the outcrop of quartz, marking a 
 possible source of detrital gold, and by the actual finding of 
 specimens on the surface. 
 
 The distribution of the gold in these deposits reminds one of 
 its position on a vanning-shovel. It may be traced up to the out- 
 crop which yielded it, or it may be scattered in the sand for half 
 a mile; but the rich and only workable part of the deposit will 
 ordinarily be found at a distance of 30 or 40 feet from the reef. 
 
 Underneath these patches of superficial gold-bearing detritus 
 there are found partially consolidated accumulations, which are 
 more extensive and, quite apart from their greater economic 
 value, are also of superior interest, because of their better-de- 
 fined geological features. 
 
 IV. THE CEMENT-DEPOSITS. 
 
 In the ordinary course of professional work I examined the 
 two most important of these deposits, at Kintore and Kanowna, 
 respectively. Since then a third formation of a similar char- 
 acter has been opened up, also at Kanowna. This I happened 
 to see when in the stages of early development, and before it 
 had been extensively exploited. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 35 
 
 The deposit of cement at Kintore was one of the earliest 
 worked. It is situated 23 miles northwest of Coolgardie, on 
 the road to Menzies. The West Australian Proprietary Cement 
 Company mined the ground with a success which was short- 
 lived, because of the restricted quantity of material rich enough 
 to pay the high costs of treatment. In four months, 7335 
 ounces of gold were obtained by treating 4115 tons in a stamp- 
 mill, supplemented by cyanide- vats. 
 
 Enough work has been done to disclose the character of the 
 deposit. Figs. 16 and 17 are representative sections obtained 
 in the open cuts. Under a thin covering of sand and dust there 
 occurs a bed of kaolin, ranging from a couple of inches to a 
 foot in thickness ; and this overlies from 15 inches to 2 feet of 
 " sand-rock," which in turn gives place to the gold-bearing 
 cement, which has an average thickness of 2J feet. The last 
 lies directly upon an irregular surface of decomposed granite. 
 
 The several layers composing the deposit are separated by 
 seams of pipe-clay, which, like the kaolin, are simply the pro- 
 duct of the decomposition of the constituents of the granite, 
 particularly the feldspar. The sand-rock may be described as a 
 coarse, incompletely consolidated sandstone or grit, consisting 
 mainly of iron-stained particles of quartz, loosely cemented. 
 The cement has a bluish-gray tinge, owing to the play of light 
 on the quartz fragments. This, too, is not quite compacted, 
 since fractures through the material do not break across the 
 pebbles, which are harder than the clay binding them together. 
 In this respect the cement differs, for example, from the South 
 African "banket," to which it has been compared. From a 
 distance, the cement looks like a coarse sandstone and exhibits 
 a rough-joint structure. The materials of which it has been 
 made up have undergone incipient sizing, so that different 
 layers of varying coarseness are distinguishable. 
 
 The bed-rock is granite, so softened by decomposition as to 
 be mistaken by the miners for a part of the alluvial deposit. 
 It is kaolinized to a depth which the neighboring mine-shafts 
 prove to reach a maximum of 130 feet. The surface on which 
 the cement lies is marked by pot-holes having a maximum 
 depth of 2 feet and a diameter reaching to 3 feet. These holes 
 are filled with cement, which is usually poor save at the rims, 
 where some of the richest mill-stuff has been obtained. 
 
 All the members of the deposit, from surface to bed-rock, 
 
36 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 contain some gold, the kaolin being the poorest. The cement 
 j.tself attains a maximum thickness of 5 feet. The richest parts 
 occur in lateral embranchments from the main body of the 
 deposit. The kaolin has become hardened and dried. It 
 breaks like shale; and its true character is obscured by the 
 down-filtering of red sand through cracks reaching to the soil 
 overhead. 
 
 The deposit extends through a number of mining claims, as 
 shown on the accompanying map (Fig. 18). It has been traced 
 for a length of three-quarters of a mile. At the east end it 
 begins as a narrow neck about 15 feet wide, and then enlarges 
 steadily to 100 feet. Occasional bulges increase this width to 
 a maximum of 250 feet. At the edge it gives place, as it thins 
 out, to 2 or 3 feet of ironstone gravel, carrying 3 or 4 dwts. of 
 gold per ton. The best part, economically, of the deposit lies 
 in the Ophelia and Hilton claims, which, it will be noted, are 
 situated at the lower end of the basin. 
 
 The bed-rock rises westward at the rate of 15 feet per 
 thousand. This fact suggested that the origin of the gold-bear- 
 ing cement was to be found in the reefs which were being profit- 
 ably mined by the Sugar Loaf Company. The workings were 
 136 feet deep at the time of my visit in September, 1897. The 
 veins traverse granite which has been kaolinized to 130 feet 
 from the surface. They consist of white quartz and are narrow 
 (4 to 12 inches), but they carry short shoots of very high-grade 
 (3 to 10 ounces of gold per ton) ore. The gold occurs native, in 
 flakes penetrating the cleavage-planes of the quartz like a golden 
 mosaic, and also in coarser particles, which, under closer exam- 
 ination, prove to be octahedral crystals with curiously rounded 
 edges. A comparison of these veins and their enclosing rock 
 with the material composing the cement-deposit unquestion- 
 ably indicates the derivation of the latter from the former. 
 The cement carries gold which is exactly similar to that seen in 
 the reefs; the quartz fragments in the alluvial are identical 
 with the stone broken in the Sugar Loaf mine. Samples of 
 both lie before me as I write, emphasizing the conclusion just 
 stated. In the cement occur particles of quartz showing 
 gold. The loose gold in the cement has been but slightly worn, 
 and the quartz pieces are rather subangular than rounded, so 
 that they can hardly be termed "pebbles;" and the deposit 
 itself is better defined as an agglomerate than as a conglomerate. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 37 
 
 The binding-material, the overlying layer of kaolin and the 
 sand-rock capping the gold-bearing stratum of cement, all ex- 
 hibit very clearly their derivation from a decomposed granite, 
 similar to that which encloses the reefs and forms the bed-rock 
 of the alluvium itself. 
 
 The topography confirms this supposed relationship. The 
 highest point along the major axis of the cement-deposit is a 
 very low ridge separating the workings of the Sugar Loaf from 
 the alluvial ground. The house of the manager of the Sugar 
 Loaf is on this divide. The reefs are 462 feet westward, and 
 only 15 feet lower where they appear at the surface. The ce- 
 ment deposit begins on the Great Dyke lease, at a point 530 feet 
 eastward, and only 8 feet lower. The cement then extends 
 on a gentle down-slope of 15 feet per thousand for a distance of 
 3600 feet* 
 
 It occupies a very shallow depression, and in its structure 
 bears internal evidence of considerable geological age, suggest- 
 ing that it was formed at a time when the Sugar Loaf reefs 
 reached the surface at a level superior to the slight ridge now 
 separating them. Reference to the map and longitudinal section 
 (Fig. 18) will aid the above description. 
 
 Another deposit of similar character has been explored at 
 Kanowna, 25 miles northeast of Kalgoorlie, and about 60 miles 
 east of the locality just described. 
 
 The discovery was made in 1893. Eadh digger secured a 
 claim 50 feet square, and sunk a shaft to the gold-bearing 
 cement which the dry -blowers had uncovered in the course of 
 their prospecting. The deposit became in due time "gophered" 
 with holes and shafts, so that the boundaries of the cement were 
 accurately determined. In 1895 an English company secured 
 the property and consolidated the claims into larger leases. 
 The expectations held out freely by responsible engineers that 
 an extremely profitable enterprise could be based on the rem- 
 nants of gold-bearing ground were wholly dissipated in the suc- 
 ceeding two years.f 
 
 The deposit lies in a shallow trough, the longer axis lying 
 
 * I am indebted to the courtesy of Mr. Alexander Brand and Mr. T. G. Paisley, 
 the managers of the two companies, for the measurements quoted. 
 
 f A gross blunder was made, simply through insufficient and unsystematic 
 sampling. 
 
38 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 east and west. The body of gold-bearing cement has a length 
 of about 700 feet and a maximum width of 105 feet (see Fig. 
 19). Vertical sections exhibit an overburden of sandy loam, 
 from a few inches to 2J feet thick. This was the material 
 worked by the dry-blowers. Then comes a layer of detritus, 
 called " wash " by the miners, composed of fragments of iron- 
 stone and quartz imbedded in clay, and reaching to a maximum 
 of 25 feet from the surface. This overlies the cement itself, 6 
 inches to 5 feet thick, and easily distinguished from its roof of 
 detritus and its floor of clay. The cement consists of particles 
 of quartz in a greenish clay. Near the rim of the trough the 
 quartz occurs in larger and more angular pieces. .A typical 
 section, obtained from a pillar in the old workings, is given 
 in Fig. 20. 
 
 The gold-contents are irregular. The whole body of cement 
 probably averaged one ounce per ton ; but only the richest parts 
 were worked, and these carried many ounces to the ton; so that 
 the remnants now accessible average, from the surface down, 
 about 3J dwts.* The clay carries 2 dwts. per ton. The material 
 was treated at neighboring stamp-mills. 
 
 When the neighboring mines, the White Feather Reward 
 and the White Feather Main Reef, were visited, it seemed as 
 natural to deduce this cement-deposit from the erosion of gold- 
 bearing quartz-veins as it had been to relate the Sugar Loaf 
 reefs at Kintore with the deposit worked by the West Austra- 
 lian Proprietary Cement Company. Further investigation con- 
 firmed this inference. 
 
 The McAulifte vein (worked by the W. F. Reward mine) 
 and the Main Reef (worked by the W. F. Main Reef mine) 
 traverse diorite at or near the line where large dikes of granite 
 porphyry penetrate. The two reefs are probably identical, and 
 have a strike which takes them right across the longer axis of 
 the cement-deposit at. a point near the head of the trough in 
 which it lies (see map, Fig. 19). A shaft recently sunk to a 
 depth of 200 feet by the Golden Cement Company, at a point 
 marked A, reached this reef by means of a crosscut, and found 
 a comparatively barren quartz-vein, carrying small spots of rich 
 ore. The enclosing rock was diorite, and the quartz itself was 
 encased on both sides by bands of clay fully 2 feet thick. 
 
 * Information which I owe to the courtesy of Mr. S. H. Williams, the manager. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 39 
 
 On comparing the veins and their encasing rock, as seen in 
 the workings of the two mines on opposite sides of the allu- 
 vial deposit, it is not found necessary to go further for the 
 origin of the latter. The cement is underlain by a clay which 
 is essentially steatite, and is as readily traceable to the neigh- 
 boring diorite as the kaolin at Kintore was deducible from the 
 granite. The green color of the cement is imparted by 
 chlorite, derived from the decomposition of the epidote in the 
 diorite. The " ironstone " of the detritus overlying the gold- 
 bearing part of the deposit consists of fragments of altered 
 diorite. The quartz in the cement and the gold accompanying 
 it are both identical with those of the reefs close by. 
 
 Here also the topography confirms the suggested explana- 
 tion. The cement lies in a shallow depression, at the upper 
 rim of which the quartz reefs cross the country. Further- 
 more, these reefs traverse a low divide, which in a rough way 
 separates the deposit from another, which slopes in the oppo- 
 site direction. The latter is known as the Fitzroy cement. In 
 this deposit rich discoveries were made during October, 1897. 
 A typical section is exhibited in Fig. 21. 
 
 Apart from their importance as depositories of gold, the 
 cements have played an interesting part in the development of 
 the gold-fields, because they often cover the tops of reefs. In 
 Fig. 22 such an occurrence* is illustrated. A similar feature 
 proved a serious hindrance to the recognition of the lodes at 
 Kalgoorlie, where worthless quartz veins were worked for some 
 time before a trench traversing the cap of cement accidentally 
 uncovered the top of one of the rich deposits of telluride 
 ore, which did not outcrop, on account of the comparative 
 softness of the lode. 
 
 V. THEORIES OF ORIGIN. 
 
 Of course, several theories have been mooted, the most fan- 
 ciful of which have naturally been those of the working miner 
 himself. The fact that the gold-bearing cement is in places 
 overlain by a considerable thickness of partially-consolidated 
 rock has led to the supposition that the deposit was a " deep 
 lead;" while the resemblance to a conglomerate has caused 
 more than one Africander to liken it to the " banket " of the 
 Transvaal. 
 
 * It is the top of the Lady Shenton reef, at Menzies. 
 
40 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 The latter is an immense shore-deposit of gold-bearing 
 conglomerates, now covered by a series of later sediments. 
 Its dimensions, comparative homogeneity and persistence are 
 in striking contrast to the narrow, restricted, irregular patches 
 of detritus which have been described as occurring in West 
 Australia. This total unlikeness renders unnecessary any dis- 
 cussion of a fancied similarity of origin. 
 
 But because this alluvium disappears under an overburden 
 of rock,* the Australian digger easily fancies he is working a 
 deposit similar to the " deep leads " with which he became 
 familiar at Ballarat, for example. A distinguished government 
 geologist from a neighboring colony visited Kanowna in Octo- 
 ber, 1897, and gave authority to the term " deep lead " by 
 using it himself. " Deep " it may be, for that is a comparative 
 adjective, but a " deep lead " in the technical sense it most 
 assuredly is not. On the Forest Hill divide, f in Placer county, 
 California, and at Ores wick, in the Ballarat district, Victoria, 
 the typical "deep leads" occur. They are, as is well known, 
 old (Miocene) gold-bearing river channels, which have been 
 saved from erosion by a cap of lava. The lava probably over- 
 flowed the original surface as a steaming mud, and is now 
 found consolidated into a volcanic rock sufficiently hard to need 
 little timbering when penetrated by underground workings. 
 The cement deposits of West Australia occur under an over- 
 burden of "made ground;" that is to say, both the deposit 
 itself and all the material under which it dips are of distinctly 
 detrital origin, the products of weathering and erosion accu- 
 mulated in shallow depressions of the much-decomposed sur- 
 face of granite or diorite. 
 
 It is the placer of a country destitute of running water. 
 The climatic conditions and the physiography of the Cool- 
 gardie gold-fields have been carefully described, in order to 
 make it evident why these deposits differ from those of more 
 favored countries, like California or New Zealand. Surely it 
 is not in keeping with the scientific method to seek for fantastic 
 or far-fetched explanations, when processes in operation to-day 
 
 * Using the word in its geological sense. Mud is "rock" as much as 
 granite. 
 
 f I append a drawing (Fig. 23) of a typical deep-lead recently examined by me 
 in this particular locality. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 41 
 
 are able to supply an adequate understanding of the observed 
 facts. 
 
 The quartz of the cement is subangular ; it has evidently un- 
 dergone very little attrition, and suggests, therefore, that it has 
 not traveled far. On comparing it with the matrix of neigh- 
 boring veins, an identity appears obvious. The examination of 
 the topography renders highly probable the derivation of the 
 one from the other. The cementing material is similarly 
 found to be the clay resulting from the decomposition of 
 the rock encasing the quartz-veins, and varying according to 
 the composition of that rock, whether it be granite or diorite. 
 Finally, the gold particles which have rendered the cement 
 worth mining are found to be identical in fineness and physi- 
 cal appearance with the gold of the neighboring veins, and their 
 scarcely-rounded edges invite the conclusion that the gold 
 ako has not been borne far from the place of its origin. The 
 comparatively unclassified condition of the deposits is in keep- 
 ing with the evidence* afforded by the material of which they 
 are composed. The absence of running water on this desert 
 plateau has prevented any such sifting-process as in other re- 
 gions leads to the deposition of well-defined layers of clay, 
 gravel and gold upon a clean bed-rock. It is an exceptional 
 illustration of the working of those agencies to whose un- 
 ceasing play is due the configuration of the earth's surface ; it 
 is geological action in its most instructive form. 
 
 VI. WATER-SUPPLY. 
 
 The early history of the gold-fields of West Australia is the 
 record of a struggle to exist amid conditions which were inimi- 
 cal to human life on account of the scarcity of water. That 
 great necessity has been, in some sort, x satisfied by the energetic 
 action of the government, supplemented by private enterprise. 
 The gold-fields are now dotted over with condensing-plants, 
 which turn the brine of the wells into water fitted for the use 
 of man and beast. Existence is thus rendered endurable ; but 
 the mining industry is still handicapped by an item of cost un- 
 known in more favored regions. 
 
 The water of the country is salt, sometimes almost to the 
 point of saturation. Sea-water contains 3J per cent, of salts, 
 three-quarters of this percentage being common salt, the 
 
42 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 chloride of sodium. At Menzies, in September, 1897, I found 
 one* of the two important mines of that district using water 
 which contained 17 per cent, of salts, and the manager in- 
 formed me that in December evaporation increased the amount 
 to 30 per cent.f For this liquid he paid 25 shillings per thousand 
 gallons. It came from a neighboring "soak." The condensed 
 (distilled) water, bought for use in the boilers, cost 1 per 
 hundred gallons. Milling in a ten-stamp-mill was carried on 
 at an average cost of 30 shillings or $6 per ton, the item of 
 water alone amounting to 13 shillings or $3.25 per ton. 
 
 Under these conditions a wet mine becomes a source of 
 revenue. Many properties at Kalgoorlie, unable to find pay- 
 ore, lessened the expenses of development by selling their water 
 to those that had mills. The price varied according to the sea- 
 son. At the Great Boulder Main Reef mine, for example, the 
 lowest price paid for water during 1897 was 3. 10s. per thou- 
 sand gallons, and the highest 11. 5s. This was piped from 
 neighboring shafts, and had not passed through the condenser ; 
 it therefore had the character of sea-water, but it was four times 
 as saline. 
 
 An analysis of the water of the Great Boulder Proprietary 
 mine gave the following results. The sample was turbid, and 
 it was found that the matter in suspension amounted to 5.25 
 grains per gallon, or .075 gramme per liter. The clear water 
 on analysis yielded : 
 
 Grammes per liter. 
 
 Silica (SiO 2 ), . . 0.038 
 
 Alumina and ferric oxide (A1 2 O 3 and Fe 2 O 3 ), . . 0.024 
 
 Lime (CaO), 1.878 
 
 Magnesia (MgO), ^ ,..._, ;.',. ,. 8.106 
 
 Soda (Na 2 O), 48.470 
 
 Carbonic anhydride (CO 2 ), 0.064 
 
 Sulphuric anhydride (SO 3 ), 6.026 
 
 Chlorine (Cl), 67.280 
 
 131.836 
 Deduct oxygen equivalent to chlorine, . , . 15.150 
 
 116.686 
 Combined water, organic matter and loss> . . . 8.534 
 
 Total solids, . . " 125.220 
 
 * The Queensland Menzies mine. 
 
 f The water of the Dead Sea varies from 20 to 26 per cent, salts, and of this, 10 
 per cent is common salt. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 43 
 
 The chief salts probably present were, therefore : 
 
 Grammes per liter. 
 
 Calcium carbonate, CaCO 3 , 0. 145 
 
 Calcium sulphate, CaSO 4 , 4.3(55 
 
 Magnesium sulphate, MgSO 4 , 5.189 
 
 Magnesium chloride, MgCl 2 , 15.144 
 
 Sodium chloride, NaCl, . 91.467 
 
 Expressed in grains per gallon, the results appear more strik- 
 ing. The proportion of common salt amounts to no less than 
 6402.7 grains per gallon. Ordinary drinking-water contains 
 about 3 grains of common salt per gallon. 
 
 The water-supply of the region comes from two sources, 
 namely, that which has collected amid the purely superficial 
 deposits of debris and drift covering the actual rock-surface, 
 and, secondly, that which has penetrated through the decom- 
 posed rock down to the zone where oxidation ceases. 
 
 Wherever a depression occurs, the prevailing rocks, granite 
 and diorite, are overlaid with a variable thickness of their 
 own detritus, which allows the collection of rain-water 
 and affords protection from too rapid evaporation. These are 
 known as " soaks." The government geologist defines them 
 as " valleys silted up with a thin covering of recent superficial 
 deposits more or less saturated with water."* At Hampton 
 Plains, 8 miles from Coolgardie, a supply of condensing-water 
 has been obtained from beds of this nature. The sectionf was 
 as follows : 
 
 Thickness. Depth. 
 
 Feet. Feet. 
 
 Clay, with ironstone gravel, .- 27 27 
 
 Fine sand, 30 57 
 
 Coarse yellow sand, 43 100 
 
 Clay, ' 4 104 
 
 Land wash, . . . . ' . . .11 115 
 
 Kaolin, 8 123 
 
 Bed-rock, . . . . . . . . 39 162 
 
 Water was struck in the third stratum, described as coarse 
 yellow sand. The bed-rock was granite. 
 
 During the wet season, some of the depressions filled with 
 such accumulations of detritus will receive more water than 
 
 * Report in connection with the water-supply of the gold-fields. 1897. A. 
 Gibb Maitland. 
 
 f From the report just referred to. 
 
44 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 they can hold, and then the eye becomes gladdened for a few 
 days by the sight of water running over the surface. As it 
 becomes diminished by evaporation it disappears from view, 
 but will be found to linger in the rock-holes, where the supply 
 is maintained by the slow drainage of the surrounding porous 
 area. These are called by the aborigines " guamma " holes. 
 The life of such natural wells depends, of course, on the dimen- 
 sions of the water-bearing depression and upon. the relative 
 porosity of the deposit which it drains. 
 
 These supplies are in their nature uncertain. The next and 
 more important source of supply is found at the ordinary 
 drainage-level of the country, namely, the horizon where the 
 oxidation of the surface ceases and the relatively hard unoxi- 
 dized rock offers a partial barrier to the free descent of the 
 waters which have percolated through the overlying formation. 
 The depth of this zone will depend upon the permeability of 
 the superficial rock-formation ; it varies from 40 feet at Earl- 
 ston to 202 feet at Kalgoorlie. A characteristic section is that 
 given by the well put down on Reserve 3096, Coolgardie, 
 where the Gold-fields Water Supply Department sunk 165 feet 
 and found 7 feet of sand, 47 feet of conglomerate and 111 feet 
 of decomposed granite. The water was found at the base of 
 the last, just above the unaltered granite. 
 
 Condensers. Frequent mention has been made of the con- 
 denser. This is a characteristic feature of every mining settle- 
 ment in the interior of Western Australia, and occupies the 
 position accorded to the public well of a European village. 
 Without this process of distillation, which renders the brack- 
 ish water of the wilderness fit for human consumption, the 
 mining industry could never have progressed beyond the 
 merest prospecting. 
 
 The introduction of condensers is traceable to the sailors 
 who took a prominent part in the early exploring expeditions. 
 The name itself suggests this ; for a landsman would be likely 
 to call the condenser a " still." When the rush to the new 
 gold-fields occurred, the government, by erecting condensers at 
 intervals along the main lines of travel, did much to diminish 
 the loss of life otherwise inevitable in times of wild excite- 
 ment by reason of the recklessness of those who joined the 
 stampede without due care for the great necessity of life in a 
 tropical desert. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 45 
 
 The process of converting brine into drinkable water is 
 simple. The salt water is put into a boiler and converted into 
 steam, which is then condensed in vessels presenting a maxi- 
 mum of cooling-surface. Ship-tanks, having a capacity of 
 400 gallons, are commonly employed as boilers, and the con- 
 densing apparatus is constructed out of the corrugated iron 
 which is everywhere employed for roofing-purposes. The 
 tanks used as boilers are usually set on edge in pairs, as shown 
 in Figs. 24 and 25. The average product of each 400-gallon 
 tank is about 300 gallons of distilled water daily. Two ver- 
 tical short iron pipes draw off the steam, which passes into 
 condensing chambers or " coolers." The latter were originally 
 plain circular tanks, which were increased in capacity by the 
 addition of sections, increasing the height. Sheets of corru- 
 gated iron were bent round until the ends met, and these were 
 united by riveting and soldering. Several such sections were 
 united, and a tubular tower, about 30 feet high and 3 feet in 
 diameter, was the result. The top and bottom were closed by 
 a flat sheet of iron. A 6-inch pipe connected the towers, and 
 steam traveled up the one tower and down the next. 
 
 This type has been superseded of late by annular chambers. 
 An outer corrugated iron cylinder, 2.5 feet in diameter, sur- 
 rounds an inner 1.5 ft. cylinder, so as to leave an annular 
 space, 6 inches wide, which becomes the condensing-chamber. 
 No attempt is made to supplement the cooling effect of the 
 surrounding air, though a brush shelter is sometimes erected 
 so as to ward oft' the direct rays of the sun.* 
 
 The daily expenditure includes the labor of two men, one on 
 each shift, and the cost of the fuel consumed. A typical con- 
 denser is that erected on the Lake View and Boulder Junction 
 mine, shown in Fig. 4. This plant has a capacity of 1,500 
 gallons of condensed water per day and cost 100. The water 
 treated comes from the mine and shaft and has a specific 
 gravity of 1.03385, the total solids amounting, according to 
 the analyses of Mr. E. S. Simpson, to 4.9308 per cent, and the 
 chlorine to 2.3933 per cent. The cost averages, during the 
 cool season, 5 shillings, and during the summer 6.5 shillings 
 
 * For many of these details I am indebted to Mr. Frank G. Grace, Kalgoorlie, 
 and to Mr. Edward S. Simpson, Government Assayer, Perth. 
 
46 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA, 
 
 FIG. 24. 
 
 in Feed Water 
 
 "V \ / ,' 
 
 o 
 
 Jb 
 
 
 
 O 
 
 Plan of Ordinary Condenser. 
 
 FIG. 25. 
 
 FRONT REMOVED | FRONT 
 
 Section and Elevation of Ordinary Condenser. 
 
THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 47 
 
 per 'hundred gallons of condensed water. The condensed 
 water is sold at from 10 to 12 shillings per hundred gallons. 
 A first-class condenser would consist of at least 8 boilers, each 
 having 400 gallons capacity and a daily output of 300 gallons, of 
 condensed water, giving the plant a daily yield of 2,400 gallons. 
 The salt water is usually bought for from 2 to 4 shillings per 
 thousand gallons. Fuel costs 20 shillings per cord, and is con- 
 sumed at the rate of 1 cord per thousand gallons of condensed 
 water. Thus the cost would be : 
 
 2 men at 4 per week of 6 days, 27 shillings 
 
 2J cords of wood, 50 . " 
 
 3, 200 gallons of salt water, 10 " 
 
 Total, . . .87 shillings 
 
 This would be at the rate of 36 shillings per thousand gallons. 
 During November, 1897, condensed water sold for 100 to 150 
 shillings per thousand gallons. 
 
 Concerning the use of salt water in the stamp-mills and 
 leaching works of Western Australia, I would say that its 
 density is an obstacle to amalgamation because of the facility 
 with which slimes are created. The finer particles of gold are 
 thus prevented from settling on the copper plates of the tables, 
 and are carried away in the tailings. At Kalgoorlie the cyanide 
 works use the natural brine successfully ; its magnesia being 
 precipitated by lime, so as to prevent the decomposition of the 
 stock-solution. 
 
 In order to aid the development of the mining industry, 
 which is still severely handicapped by the want of a sufficient 
 supply of water, the government of West Australia has decided 
 to carry out a hydraulic enterprise of great magnitude. It is 
 proposed to supply 5,000,000 gallons of fresh water per day to 
 the Coolgardie gold-field by building a pipe-line from the Dar- 
 ling range, where the Helena river will be impounded by a 
 concrete dam 100 feet in height and 650 feet long. The source 
 of supply is 320 feet above sea-level, while the service-reser- 
 voir at Coolgardie will be on Mt. Burgess, at a height of 1670 
 feet, or 1350 feet higher. These two reservoirs will be con- 
 nected by 330 miles of 30-inch steel-pipe. Nine pumping- 
 stations will be required. The appropriation for this work is 
 $12,500,000. The annual operating expenses will probably 
 
48 THE ALLUVIAL DEPOSITS OF WESTERN AUSTRALIA. 
 
 approximate $1,600,000, and water will be delivered through a 
 hundred miles of distributing pipes at a cost of 3 shillings and 
 6 pence, or 84 cents, per thousand gallons. 
 
 It will occur to the reader to ask whether boring for artesian 
 wells has been attempted. Yes; in obedience to the public 
 demand, the government put down a bore at Coolgardie which 
 reached a depth exceeding 2000 feet and found granite. The 
 geological conditions render an artesian flow of water highly 
 improbable. Nevertheless, in this colony, as elsewhere among 
 the arid tracts of Australia, there is a whispered hope of find- 
 ing a subterranean river. As the Carson and the Humboldt 
 are swallowed up by the alkali wastes of Nevada, so in the 
 desert plains of this southern continent there are many streams 
 w^hich flow into the interior and lose themselves in the sand 
 or find for themselves an undergound channel.* This fact has 
 given rise to conceptions, more poetic than scientific, of a great 
 subterranean river yet to be discovered, and destined in days 
 to come to make the desert break forth into fertility. It is a 
 dream. No irrigation can turn the wastes of quartz-sand into 
 waving fields of wheat. Time, geological time, covering a 
 period to measure which the duration of a man's life is an in- 
 adequate unit, can alone render the wilderness fit for human 
 habitation. 
 
 * This occurs in Queensland, where the geological conditions are quite differ- 
 ent. Several very successful bore-holes have been put down, an abundant arte- 
 sian flow being obtained at depths of 2000 feet and over. 
 
SUBJECT TO REVISION. 
 
 [TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
 
 The Formation of Bonanzas in the Upper Portions of 
 Gold- Veins. 
 
 BY T. A. RICKARD, DENVER, COLORADO. 
 
 (Richmond Meeting, February, 1901.). 
 
 INTRODUCTORY. 
 
 THE presentation to the Institute, eight years ago, of the paper 
 of Posepny on " The Genesis of Ore-Deposits " has borne fruit 
 in much fresh investigation, as is evidenced, for example, by 
 the group of very valuable papers, by distinguished members 
 of the United States Geological Survey, read at the Washing- 
 ton meeting discussions of general principles particularly sug- 
 gestive to those who are engaged in mining. 
 
 Posepny, in the discussion of his famous treatise, said that 
 the present writer seemed to look at every new conception in 
 ore-deposition " from the sole standpoint of its immediate use- 
 fulness in mining."* Protesting mildly against " sole " and 
 " immediate," I accept the impeachment. It calls for no defence. 
 
 THE DEVELOPMENT OF RECENT THEORIES. 
 
 Given the idea of an underground water-circulation as the 
 chief factor in the deposition of ore, the next step in the in- 
 quiry as to the genesis of such deposits is the endeavor to de- 
 termine which particular part of the general water-circulation 
 is responsible for the results. Around this question have cen- 
 tered the controversies of a generation, and to these controver- 
 sies we owe the gradual clarification of our ideas upon the pro- 
 cesses of ore-formation. It is unnecessary to sketch here their 
 progress from Werner to Le Conte, who combated in 1883 the 
 extreme views of the lateral-secretionists, and in 1893 opposed 
 the narrow interpretation of the ascensionist-theory. The gen- 
 erally accepted opinions of to-day are a well-deserved tribute to 
 his philosophic discrimination. 
 
 * Trans., vol. xxiv., 996. 
 
2 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 Thanks to Prof. Van Hise and Mr. Slichter, whose work he 
 utilizes, we have now arrived at a comprehensive conception 
 of the underground circulation, which emphasizes the conclu- 
 sion that sulphide-ores are generally deposited by ascending 
 waters. In estimating the importance of this conclusion, it is 
 to be remembered that, apart from placers and iron-mines, the 
 largest portion, by far, of the ores exploited by the miner are 
 sulphides. Morever, it has been shown that the other, equally 
 essential, parts of the circulation, namely, its lateral and de- 
 scending portions, particularly the latter, also play their part, 
 to which many " secondary enrichments " are due. 
 
 This approach toward an understanding of the processes of 
 secondary enrichment in ore-deposits is an extremely important 
 advance in the application of geology to the exploitation of 
 mines. For such enrichments pre-eminently constitute the ore- 
 masses valuable to man. Chemistry and physics may unite in 
 determining the conditions favorable to the precipitation of gold; 
 geology may unravel the intricacies of rock-structure, but it 
 does not come within the province of these sciences to decide 
 whether a gold-vein will prove rich enough for profitable min- 
 ing. Mature knows no ratio of sixteen to one, or any other 
 standard of monetary value. Therefore, the determination of 
 the particular conditions favorable to the mere occurrence of 
 gold-ores remains but a barren discovery until it includes some 
 suggestion as to the search for the richest portions. To the 
 geologist, material carrying 2 dwts. of gold per ton is as truly 
 an auriferous deposit as if it contained 12 dwts. per ton ; but, 
 under existing economic conditions, the miner may regard the 
 former as only fit for macadam, and the latter as potential of 
 fortune. 
 
 When the science of ore-deposits, therefore, has predicted 
 with certainty the places where gold can be found, it has ful- 
 filled a conclusive test of a true theory. But this means to the 
 miner no more than the restriction of his search for profitable 
 gold-deposits to those places where there is any gold at all a 
 restriction which, after all, amounts to little, for the progress 
 of scientific inquiry and practical exploration has rather en- 
 larged than diminished the field of the distribution of this 
 metal. A greater service will be the determination of the con- 
 ditions which control the formation and distribution of those 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 6 
 
 particular portions of the multitudinous deposits of gold which 
 constitute the secondary enrichments of the geologist and the 
 bonanzas of the miner. 
 
 'Such a desired consummation seems now to be nearer of 
 attainment. The practical result of the papers of Messrs. 
 Van Hise, Emmons and Weed will be to direct attention to the 
 one line of inquiry most useful to the miner. Unquestionably 
 the theories of secondary enrichment have been largely sug- 
 gested by the experience of the men whom the geologists have 
 met at the mines ; and the invaluable assistance thus given to 
 mining engineers is a pleasant outcome of such an exchange 
 of views. 
 
 THE ENRICHMENT OF GOLD- VEINS ^"EAR THE SURFACE. 
 
 A quartz lode carrying gold in association with pyrite is here 
 taken as the type of deposit under discussion. In lodes of this 
 kind, it is a common experience to find bodies of rich oxidized 
 ores extending to a variable depth from the surface. In this 
 general phenomenon of enrichment two processes must be 
 separately recognized, namely, relative enrichment by a method 
 of natural concentration and positive enrichment by the de- 
 position of additional gold through secondary reactions. 
 
 Enrichment by Concentration. 
 
 The iron sulphide accompanying the gold is removed by 
 weathering. Weathering is a process of chemical decomposi- 
 tion and mechanical disintegration in which oxidation is aided 
 by the shattering of the rock due to the alternate expansion 
 and contraction of the water present in its pores, seams and 
 cavities. The depth to which these effects extend will depend 
 upon the facilities afforded for the penetration of surface- 
 waters carrying free oxygen; and it will be regulated by the 
 local groundwater-level. The results observed usually cease at 
 the groundwater-level because, at that horizon the descending 
 surface-waters become mingled with the larger body of neu- 
 tralized water, and so lose their free oxygen. When, however, 
 they can find channels permitting a relatively rapid passage, 
 they may not become at once diffused, and may thus continue 
 their oxidizing action even below that level. But the actual 
 lowering of the groundwater-level, by a change of surface alti- 
 
4 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 tude or hydrostatic conditions, affords the chief factor in en- 
 larging the scope of such oxidizing action on the part of the 
 surface-waters. 
 
 The chemistry of the process is pretty well understood, and 
 need not be discussed here. 
 
 In the case of enrichment by concentration, the evidence 
 indicates that the leaching and removal of the pyrite has been 
 affected without shifting the gold, which remains behind in its 
 native state. I have specimens from Idaho and West Australia 
 exhibiting crumbly native sulphur, within the cubic cavities 
 vacated by the pyrite, and in those from West Australia there 
 is also gold in fine crystals which are readily shaken loose. 
 The removal of pyrite ; the occurrence of fine particles of gold 
 in the vacant casts produced by this removal, and the forma- 
 tion of a sintery honeycombed mass of iron-stained quartz are 
 familiar aspects of the process of natural concentration. 
 
 Weathering, then, by removing the baser and more soluble 
 constituents of the vein, decreases the weight without dimin- 
 ishing the volume of the ore, which thus becomes so much the 
 richer per ton. Iron-stained gossan, rich in gold, is a familiar 
 occurrence in mining, and the frequent development of such 
 material has had a far-reaching effect in determining the char- 
 acter of the industry. Apart from the richness of such oxi- 
 dized ore, its metallurgical docility greatly enhances its value. 
 In comparison with the unaltered and relatively refractory 
 pyritic ores, the oxidized material is not only easier to crush, 
 but also easier to treat by amalgamation, chlorination, etc. 
 Hence the contrast which is occasionally offered between the 
 early successes of the discoverers of a gold-vein and the sub- 
 sequent troubles of the mining company which buys their 
 property. The gossan of the gold-vein has been the source of 
 a large part of the world's store of the precious metal ; and to 
 it we owe the successful beginnings of many districts, which, 
 if they had been compelled to commence operations upon re- 
 fractory pyritic ore, would have waited long for their active 
 development. 
 
 Secondary Enrichments Due to Descending Surface- Waters. 
 
 The diagnosis of the general process by which these are 
 formed by descending waters has been stated in clear terms 
 in the contributions of Messrs. Van Hise, Emmons and Weed. 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 5 
 
 The occurrence of restricted bodies of extraordinarily rich 
 gold-bearing quartz has been a startling feature of gold-mining 
 in all countries. From them fortunes have been made with 
 picturesque suddenness ; and by means of them the inexperi- 
 enced have been led into sanguine expectations, the failure of 
 which has brought disasters not less romantic, though much 
 less welcome to their victims. Such instances have furnished 
 matter for proverbs concerning the uncertainty of mining ; but 
 they are soon forgotten. Nevertheless, the uncertain occur- 
 rences of rich ore on which they are based present an important 
 feature of the ore-deposits in all gold-mining districts, though 
 they are more particularly characteristic of desert regions, 
 such as the area of the Great Basin, stretching between the 
 Rocky Mountains and the Sierra Nevada, and also those arid 
 parts of Australia and West Australia which have yielded so 
 much of the wealth of the colonies. 
 
 The outcrop of a gold-vein is not always the richest portion. 
 The sintery gossan formed at the immediate surface may be 
 poor in gold, and yet may be succeeded near, or even below, 
 the water-level, by extremely rich masses of half-decomposed 
 pyritic ore. In such cases it would appear that the gold had 
 been leached out of the oxidized portion of the lode, and had 
 migrated in the wake of the iron until precipitated, so as to 
 form the secondary enrichment now under discussion. 
 
 In considering the formation of these bonanzas, one of the 
 first problems presented is the question of the mode of occur- 
 rence of the gold in the pyritic quartz of the lode. The evidence 
 as yet available indicates that the gold does not exist in chemi- 
 cal combination with the iron sulphide of the pyrite, but usually 
 occurs in minute filaments or crystal aggregates distributed 
 through the substance, and especially along the structural 
 planes, of the pyrite. In my collection I have a handful of 
 fragments of pyrite obtained from the Orphan Boy mine, in 
 Boulder county, Colo. This mine was the beginning and end 
 of a mining excitement which happened, in the spring of 1892, 
 in connection with a locality named Copper Rock. Under a 
 magnifying-glass the specimens exhibit little crystals of gold, 
 which, by the rounding of their edges, appear in places as 
 globules distributed over the facets and in the crevices of the 
 pyrite. 
 
 The behavior of such gold-ore under metallurgical treatment 
 
6 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 also suggests strongly that its usual mode of occurrence is 
 analogous to the above example. When gold-bearing pyrite is 
 treated by cyanidation, the gold may be leached out without 
 deformation of the pyrite or any other change in its appearance 
 except the acquisition by its facets of a pitted surface suggest- 
 ing cavities left by the removal of a soluble constituent. More- 
 over, there are many mining districts yielding gold from pyritic 
 veins in which the native metal is rarely seen. The ores of 
 G-ilpin county, in Colorado, for example, contain an average of 
 from 10 to 15 per cent, of iron and copper pyrites ; and I know 
 from frequent trial that when crushed and washed in a pan, 
 such material, even though very rich, will not yield a " color," 
 that is, a speck of visible metallic gold. Nevertheless, in the 
 stamp-mill these ores yield their gold to amalgamation, indicat- 
 ing by their behavior in this respect that the gold is in a condi- 
 tion of such freedom as to permit its separation by a crude 
 mechanical process, and its subsequent ready combination with 
 mercury so as to form an amalgam. 
 
 The gold which occurs thus in the pyrite of the quartz-vein 
 is soluble in many natural reagents, some of which are formed 
 in the very process of weathering which leaches the pyrite, 
 while others are known to be present in the surface-waters 
 which circulate through the lode-fractures under observation 
 at the present day. By whatever means it is dissolved, the 
 gold is then supposed to be carried by the surface-waters* in 
 their descent toward the groundwater-level, where it is pre- 
 cipitated under conditions to be discussed in due course. 
 
 Solvents. 
 
 In the process of weathering, the pyrite yields many subor- 
 dinate compounds, such as sulphuretted hydrogen, sulphurous 
 and sulphuric acid, and proto- and sesqui-sulphates of iron. Of 
 the latter, the sesqui-sulphate, Fe 2 (S0 4 ) 3 , is a solvent for gold, 
 and has been cited by Wurtz and Le Conte in early discussions 
 concerning the origin of masses of native gold in oxidized 
 ores. Dr. Richard Pearce, in later years, has frequently drawn 
 attention to the probability that this sesqui-sulphate is a factor 
 in the process of gold-deposition.* 
 
 * Presidential Address, Proc. Colo. Sci. Soc., vol. iii., part ii. (1889), p. 244. 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 7 
 
 The gold-deposits in the cavernous quartzite of Battle Mt., 
 Colo.,* have characteristics which appear to confirm this view. 
 In these ores large pieces of native gold, of a nuggety appear- 
 ance, but really crystalline in structure, have been found asso- 
 ciated with horn-silver and the sesqui-sulphate of iron. The 
 latter occurs in lumps, mixed with clay ; and although these 
 are very rich irt gold, the gold occurs in a form not to be de- 
 tected by careful panning. Analyses of several large lots of 
 ore showed the presence of 12 per cent, of the hydrated sesqui- 
 sulphate of iron.f 
 
 But other solvents, capable of doing this work, also occur in 
 nature, and, although the amount of any one of them to be de- 
 tected in existing surface-waters may be minute, we have to re- 
 member that the processes of nature are permitted so much 
 more time than those of the laboratory that the dilution of the 
 solution is compensated by the quantity of it. 
 
 Most writers refer to chlorine as a possible reagent. Such a 
 reference is suggested not only because it is a prominent re- 
 agent in the metallurgical practice of to-day, but also by the 
 fact that it has a wide distribution throughout nature in the 
 form of common salt. This is most apparent in arid regions 
 where evaporation causes concentrated solutions to be formed. 
 Thus, in the deserts of West Australia the water encountered 
 in the mines is always brackish, and frequently contains more 
 salt than the sea.J The water of the Great Boulder Proprie- 
 tary mine, at Kalgoorlie, in 1897, contained 6402 grains of 
 common salt per gallon. A considerable amount of magne- 
 sium chloride was also present. In some of the water used in 
 the stamp-mills, and obtained from temporary "lakes," || the 
 salts were present up to the point of saturation and the liquid 
 carried further salts in suspension, so that the amount reached 
 as high as 30 per cent., rendering the term " brine " more suit- 
 able than " water." This liquid contained 17 per cent, of salts 
 
 * F. Guiterman, "Gold Deposits in the Quartzite Formation of Battle Moun- 
 tain, Colorado," Proc. Colo. Sci. Soc., vol. iii., part iii. (1890), pp. 264-268. 
 
 t Ibid., p. 266. 
 
 J Sea-water contains 3 per cent, of salts, three-quarters of which is common 
 salt, the chloride of sodium. 
 
 \ This is equivalent to 9 per cent. 
 
 || "Sinks" or salt-marshes. They form an important feature of the physiog- 
 raphy of West Australia, 
 
8 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 in solution even when most diluted by recent rains, and it 
 therefore afforded a parallel to the Dead Sea, the waters of 
 which contain from 20 to 26 per cent, of salts, of which 10 per 
 cent, is common salt. These excessive percentages are not due 
 to the presence of deposits of salt in the rocks of the district, 
 but simply to the concentration brought about by the excessive 
 evaporation* which takes place in a hot, arid climate. 
 
 Mine-waters frequently contain a noteworthy quantity of 
 chlorine, as chloride of sodium. At the Mammoth mine, in 
 Final county, Arizona, the water carries five grains of salt per 
 gallon, while the well-water, used in the stamp-mill, situated in 
 the valley below the mine, contains twice as much.f This 
 would be equivalent to six grains of free chlorine per gallon. 
 The larger amount contained in the water from the well, as 
 compared with that in the drainage of the mine, suggests the 
 results of surface-leaching. Even in mountainous districts, 
 such as Cripple Creek, Colo., the mine-waters carry chloride 
 of sodium to a noteworthy extent. The water of the Inde- 
 pendence mine contains three grains per gallon. 
 
 Another suggestive feature is offered by the abundance of 
 horn-silver or cerargyrite, the chloride of silver, throughout the 
 dry tracts of Arizona, New Mexico and Nevada. J Prof. Pen- 
 rose emphasizes this interesting fact, and connects it with the 
 bodies of salt water which still survive in places as " sinks " 
 and " lakes. " Furthermore, the oxi-chloride of copper, ata- 
 camite (which derives its name from the Atacama desert, be- 
 tween Chili and Peru), is frequent in these regions. Another 
 and more uncommon mineral may also be mentioned in this 
 connection. In the Mammoth mine, already cited, and in the 
 well-known Vulture mine, both in Arizona, the precious metals 
 are associated with vanadinite, which contains chlorine as a 
 chloro-vanadate of lead, 3Pb 3 (V0 4 )PbCl 4 .|| Thus the chlorides 
 
 * The rate of evaporation, in the region mentioned, has been estimated to be 
 as much as 7 ft. per annum. 
 
 f As I am informed by Mr. T. G. Davey. 
 
 I The general occurrence of horn-silver in the outcrops of lodes throughout 
 the southern parts of Arizona and New Mexico has originated the term "chlorid- 
 ing" which the miners employ as a synonym for "prospecting," which, by the 
 way, the Australian calls "fossicking." 
 
 g R. A. F. Penrose, Jr., "The Superficial Alteration of Ore-Deposits," The 
 Journal of Geology, vol. ii., No. 3, 1894. II Dana. 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 9 
 
 of copper, lead and silver are found in the oxidized ores of 
 these regions, while the corresponding combination of gold is 
 absent. The explanation is obvious. The chloride of gold is 
 an unstable and readily soluble compound, while the minerals 
 formed by the corresponding combination with the baser 
 metals are comparatively insoluble in water, especially the 
 chloride of silver, for the abundance of which there is therefore 
 a good reason. It remains but to add that, in several Arizona 
 mines which I have sampled, the ores above the water-level 
 carried a notable proportion of silver with very little gold, 
 while in depth the silver contents have diminished and the 
 gold has increased, especially in the vicinity of the water- 
 level.* 
 
 Of the many reagents which would liberate the chlorine 
 from salt, it is only necessary to mention ferric sulphate and 
 sulphuric acid, both derived from the ordinary oxidation of 
 pyrite. The hydrochloric acid thus formed would yield free 
 chlorine in the presence of manganese oxides,f which are very 
 prevalent in the upper portion of gold-lodes, in the form of the 
 black earthy mineral, psilomelane. 
 
 There are other possible solvents which need not be dis- 
 cussed here. 
 
 Predpitants. 
 
 Whatever the solvents which leach out the gold from the 
 superficial portions of the vein, there is assuredly no lack of 
 precipitants. It is probable that the gold does not migrate far 
 before encountering conditions which compel deposition. Even 
 when it is eventually carried to a considerable distance it is 
 most likely that such removal is effected by alternating stages 
 of precipitation and solution. 
 
 Organic matter is a probable precipitant for the gold in 
 such surface-waters. It exists deeper than hasty observation 
 would suggest. At the Great Boulder Main Reef mine, at 
 Kalgoorlie, I saw the roots of trees which, in their energetic 
 search for moisture, had attained a depth of 85 ft. below the 
 surface ; and at the Sugar Loaf mine, near Kunanalling (also 
 
 * I may instance two well-known mines, the Mammoth and the Commonwealth. 
 t See the experiments made by Dr. Don, to test this matter, Trans,, xxvii., 
 p. 599. 
 
10 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 in West Australia), I saw a similar occurrence at a depth of 
 74 ft* 
 
 Another agency which, under certain chemical conditions, 
 is a probable factor in reducing the gold from surface-waters, 
 is pyrite itself. Thus, the gold dissolved from the decomposed 
 pyrite at the surface may be precipitated upon the unoxidized 
 pyrite deeper down. Among the exhibits belonging to the 
 Colorado Scientific Society is a bottle containing cubes of 
 pyrite, on the faces of which crystals of gold are to be seen. 
 They are the result of one of Mr.Pearce's experiments. The gold 
 of a Cripple Creek ore was dissolved by using common salt, sul- 
 phuric acid and psilomelane as reagents, the chlorine being 
 thus obtained in a manner analogous to conditions which prob- 
 ably occur in nature. This solution was placed in a small 
 bottle, and to it were added a few large pure crystals of pyrite 
 from the St. Louis mine, at Leadville. After several months 
 the gold became precipitated in the manner described. In 
 this connection the story of Daintree's experiment, which I 
 have quoted before, f is worth repeating. In 1871, Daintree 
 commenced a series of experiments at Dr. Percy's laboratory 
 at the Royal School of Mines, London. In a number of small 
 bottles he placed a solution of chloride of gold, and to each he 
 added a crystal of one of the common metallic sulphides, such 
 as pyrite, blende, galena, etc. At the time when Daintree 
 died, a few years later, no results could be discerned ; but one 
 of the bottles, containing the gold solution and a crystal of 
 common pyrite, was removed to Dr. Percy's private laboratory, 
 in Gloucester Crescent, and there, in 1886, the experiment was 
 completed by the discovery of a cluster of minute crystals of 
 gold upon the smooth surface of the pyrite. The experiment 
 had occupied fifteen years ; and on account of its very length 
 it may be said to have more nearly approached the actual con- 
 ditions occurring in nature. 
 
 In a case like that of the " Indicator," at Ballarat, which I 
 
 * Since writing the above I have read Professor Vogt's very valuable contribu- 
 tion, and I note that he mentions having seen, among the mineral exhibits at 
 Paris, specimens of such roots, from the Great Boulder Main Reef mine, on 
 which gold had actually been precipitated. " Problems in the Geology of Ore- 
 Deposits," pamphlet edition, page 43. 
 
 f Trans., xxii., 313. 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 11 
 
 have lately described again,* it maybe questioned whether it is 
 the pyrite in the thin seam of graphitic slate or the carbonaceous 
 matter of the latter which causes the precipitation of the gold. 
 Even if the pyrite was the decisive factor, it must be remem- 
 bered that it, in turn, probably owed its previous deposition to 
 the action of the carbonaceous precipitant in the Indicator 
 seam. This would apply also to the beds of black slate which 
 have had so marked an influence on the occurrence of gold in 
 the Gympie district, f Queensland, but it would not, I think, 
 be applicable to the Rico deposits, J where pyrite is not an 
 especial constituent of the black shales, as compared with the 
 sandstone beds of the same stratified series. 
 
 Solution and Precipitation. 
 
 It is to be noted that in the two examples of ore-forming pro- 
 cesses which have been considered, the gold in the superficial 
 part of the vein is supposed, in one case, to remain in the gos- 
 san after the pyrite has been removed, while in the other in- 
 stance the gold also is dissolved and carried elsewhere. This 
 may appear contradictory. It is a good illustration of the per- 
 plexities arising from the application of chemical hypotheses to 
 the theory of ore-deposition. 
 
 Nature knows no interval of inaction ; solution is going on at 
 one time, precipitation at another. The gold is constantly the 
 object of one or the other activity. After the pyrite is removed, 
 or while it is still undergoing leaching, the gold is being dis- 
 solved, but more slowly than the baser metals. That which 
 remains to enrich the gossan may well be supposed to be the 
 survival from a larger quantity of gold which has been under- 
 going slow solution. The gold which was deposited deeper 
 down, from the surface-waters, may, as erosion takes away the 
 upper part of the vein, eventually find itself close to the sur- 
 face and undergo re-solution. It is a question whether the 
 mining of to-day breaks in upon the gold-deposits at one stage 
 or another of a continuous process. The miner finds the bal- 
 ance of gold left on deposit from a current account in Nature's 
 
 * "The Indicator Vein, Ballarat, Australia." Trans., xxx., 1004. 
 f J. K. Don. "The Genesis of Certain Auriferous Lodes." Trans., xxvii., 
 577-580. 
 
 J The Enterprise Mine, Eico, Colorado." Trans., xxvi. , 906. 
 
12 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 bank. Solution and precipitation are everywhere in action ; it is 
 the excess of one or the other which determines the formation 
 of ores. 
 
 THE DISTRIBUTION OF ORE-BONANZAS. 
 
 The shifting of the zone of oxidation is a principal factor in 
 determining the distribution of rich ores. By the erosion of 
 the superficial portions of the vein, in common with the en- 
 closing rock, the further downward penetration of the oxidiz- 
 ing agencies is facilitated. The depression of the ground- 
 water-level lowers the zone at which precipitation of gold, from 
 descending surface-waters, takes place, while, on the other hand, 
 when a change in the hydrostatic level causes the groundwater 
 to rise, the zone of deposition moves up. In both cases the 
 tendency is to give vertical extension to the rich mass of sec- 
 ondary gold-ore, and thus to produce the occurrence which the 
 miners term a " shoot." 
 
 Erosion is followed by another result, in itself of great im- 
 portance to gold-mining. The steady removal of the super- 
 ficial part of the vein causes the lower portion, which has been 
 enriched at or below the groundwater-level, to undergo a rela- 
 tive elevation by being brought nearer to the surface. In this 
 way the bonanza-zone, in process of time, may become the out- 
 crop. This appears to me to explain the formation of the extra- 
 ordinarily rich bunches of specimen-quartz, such as made West 
 Australia famous in 1894 and 1895, and started the mining 
 stampedes of other days elsewhere. In many instances for- 
 tunes have been gathered almost at the grass-roots from veins 
 which, on systematic development, have proved unprofitable. 
 The gold-quartz veins of West Australia traversed rocks of 
 great geological antiquity which have not, during late geolog- 
 ical periods, undergone any notable disturbance. We do not 
 know at what period the veins were formed ; but, even though 
 their formation dates no further back than the beginning of 
 the Tertiary, they have since been continuously exposed to the 
 same quiet forces of erosion which have leveled the region 
 until it appears as an arid table-land strewn with the wreckage 
 of geological time. 
 
 Whatever the alternations of slow depression and elevation 
 which have affected this region, as part of a continental area, 
 it is certain that erosion has been long at work with patient 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 13 
 
 constancy. Throughout this period chemical agencies have 
 been active in the zone of weathering, near the surface, remov- 
 ing the gold to the zone of precipitation, near the groundwater. 
 Whatever the slight changes which have marked the level of 
 the groundwater from time to time, erosion has continued un- 
 interruptedly, and therefore it has steadily gained, with the 
 result that the enriched portion of the vein has been brought 
 nearer and nearer to the actual surface, until it finally appears 
 as the outcrop which rewards the search of the prospector. 
 
 The Localization of Ore-Shoots. 
 
 To the miner the localization of these richer portions of the 
 vein is of more immediate practical interest than the theory of 
 their origin. A gold-vein is not a homogeneous mass of aurif- 
 erous quartz, of tabular form, penetrating the rocks like a 
 sheet of paper, but rather as an irregular occurrence of ore, the 
 composition and shape of which are very variable, because they 
 are the result of chemical agencies and structural conditions of 
 great complexity. While the traces of the agencies which pre- 
 cipitated the ore are obscure, because they have been largely 
 obliterated by subsequent chemical action, the relation between 
 the vein and its encasing rock can often be traced by observa- 
 tion. In this direction the miner obtains great aid from the 
 geologist. The transactions of this Institute and the publica- 
 tions of the IT. S. Geological Survey contain numerous clear 
 expositions of such structural relations. The monographs on 
 the Leadville and Eureka mining districts may be especially 
 instanced as affording striking examples of the direct applica- 
 tion of geology to underground work. 
 
 Australia. One of the best examples of the localization of 
 rich ore came under my notice in 1890 in the Bright mining 
 district. Bright is geographically in the Australian Alps, and 
 geologically in the Upper Silurian slates and sandstones. 
 Though these rocks have undergone metamorphism, and ex- 
 hibit a well-developed cleavage, yet their bedding has not been 
 obliterated. The veins cross the bedding-planes of the enclos- 
 ing country both in strike and dip. When investigating the 
 distribution of the ore in the mines of this district, I found that 
 the ore-shoots had a pitch corresponding with the line of inter- 
 section between vein and country. This was well illustrated at 
 
14 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 the Shouldn't Wonder mine, 7 miles from the town of Bright. 
 The lode was a simple quartz vein from 15 to 24 in. wide, 
 carrying a small percentage of pyrite. It had a strike of N. 
 28 W. of K and a dip to the NE. of about 75, while the 
 country dipped SW. 79 and had a strike of K 55 W. The 
 plane of the vein cut across the beds of the country and the 
 intersections thus produced were to be seen along the foot-wall 
 of the lode as lines, pitching 42 to 46 southward. While the 
 foot-wall was more regular than the hanging, and therefore ex- 
 hibited this feature best, yet the hanging also carried lines cor- 
 responding with those observed on the opposite wall. 
 
 The boundaries of the ore-shoots in the mine followed these 
 lines ; and the longitudinal section of the workings, as seen on 
 the mine-maps, proved also that these lines of intersection had 
 an inclination which coincided with the trend of the ore-bodies, 
 as stoped out between the four successive upper levels of the 
 property. 
 
 At the Myrtle mine, in the same district, there was the same 
 correlation between the pitch of the ore-bodies and the line of 
 intersection of the wall of the lode with the bedding-planes of 
 the enclosing country. The stratification was distinct, the 
 rocks consisting of altered, silicified slates of a gray to gray- 
 blue tint. In the stopes above the 700-ft. level the pay-ore was 
 separated from the normal valueless quartz of the lode by a 
 small step, due to the irregular fracture of the vein in crossing 
 two beds of unequal hardness. It marked the line of inter- 
 section between lode-plane and country bedding, and also 
 proved to be the boundary of the pay-shoot. In the different 
 portions of the mine the variation in the dip of the country 
 produced variations in the angle of the lines of intersection, 
 and also in the pitch of the ore-shoots. 
 
 It is not often that the formation traversed by a vein has 
 such a simple structure as was presented by these Silurian 
 sedimentary rocks; but it is probable that in other districts 
 also the pitch of the ore-bodies may have been determined by 
 structural conditions of a similar kind, which have been ob- 
 scured, however, by metamorphism. 
 
 Colorado. Experience has shown that the intersection of 
 fractures favors the occurrence of rich ore-bodies. An inter- 
 esting example was afforded by the Moon- Anchor mine, at 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 15 
 
 Cripple Creek, in 1899. This is illustrated in Fig. 1. The ore 
 in the mine occurs in a lode-channel marked by a band of 
 fractured andesite breccia. At the 400-ft. level a small dike 
 (EF) of granite, 2 to 6 in. thick, intersects the lode-channel at 
 a place where a counter-fracture (CD) also traverses it. A 
 triangle is produced by these intersections, and the ore is 
 
 FIG. 1. 
 
 FORMATION OF ORE 
 AT INTERSECTION OF FRACTURES 
 
 SCALE. ABOUT 30'= 1 IN. 
 
 ORE 
 
 \ CROSS DIKE 
 
 MOON ANCHOR MINE, CRIPPLE CREEK. 
 
 ANDESITE BRECCIA 
 
 Bormat * Co.. X.T. 
 
 proved to surround a block of ground which is also mineralized, 
 but not sufficiently so to be regarded in its entirety as pay-ore. 
 At the crossing of the dike and cross-fractures a very rich 
 body of telluride-ore was encountered. 
 
 This reminds me of the Yankee Girl ore-body, mentioned 
 by Emmons.* This body of ore was of phenomenal richness, 
 
 "The Secondary Enrichments of Ore-Deposits." 
 edition. 
 
 Page 19 of pamphlet 
 
16 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 many ten-ton lots being shipped which carried 7 or 8 ounces of 
 gold and 3000 to 4000 ounces of silver per ton. The ore was 
 also rendered remarkable by carrying the rare mineral stro- 
 meyerite, a sulphide of silver and copper. Mr. Emmons speaks 
 of the bonanza turning into low-grade pyritic ore as depth was 
 attained. I may add* that this change was not gradual, but 
 sudden, and coincident with certain structural relations. At 
 the surface, the vein consisted of comparatively low-grade ore, 
 which led to the finding of a nearly vertical " chimney," aver- 
 aging only 25 to 30 ft. in diam., of extraordinarily rich ore, 
 consisting of the copper sulphides, bornite and erubescite, with 
 stromeyerite and barite. The gold in the ore was associated 
 with the barite. From the second to the sixth level, at about 
 500 ft. below the surface, this bonanza proved immensely pro- 
 ductive; then, suddenly, a flat floor, dipping W. and accompanied 
 by clay, crossed the deposit. This flat vein was worked for 90 
 ft., from the south drift at the No. 6 level, and contained ore 
 similar to that of the Yankee Girl chimney. The latter was found 
 again deeper down, and out of its former line of descent, but 
 it was much diminished in richness, and appeared to merge into 
 the general body of low-grade copper and iron pyritesf which 
 characterized the lode at the tenth level. This mine and its 
 neighbors, the Robinson and Guston, are idle now. They are 
 in the andesite breccia of the San Juan region. The Yankee 
 Girl chimney was situated, I believe, at the crossing of three 
 lode-fractures, appearing as breaks in the andesite, which was 
 bleached and mineralized where they traversed it. It was a 
 curious feature of this mine, and of the Guston also, that the 
 short, very rich bonanzas of the upper levels gradually lost 
 their definition, that is to say, they became no richer than the 
 intervening portions of the lode. This was interpreted as a 
 " lengthening " of the ore-shoots, which may be true, viewed 
 in one way ; but I think that it should be more properly re- 
 garded as an impoverishment of the lode, marked by a disap- 
 pearance of the bonanzas. The surface-waters of these mines 
 are very acid, as -Mr. Emmons remarks. At the Yankee Girl 
 mine it became necessary to encase the pipes in redwood, brought 
 
 * From notes made during an examination of the mine in January, 1892. 
 f Assaying 20 to 60 ozs. silver, 1 to 4 dwts. gold, 5 to 15 per cent, copper. 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 17 
 
 from California. I found that the water issuing from a shallow 
 adit (73 ft. below the collar of the shaft) readily precipitated 
 copper on scrap iron. Ore-forming agencies were evidently 
 still at work. 
 
 California. In California, especially in that mining region 
 which follows the foothills of the Sierra Nevada and traverses 
 the counties of Amador, Calaveras and Tuolumne, the occur- 
 rence of pockets of rich ore, full of native gold, is a notable 
 feature of the superficial parts of the quartz-veins. These 
 pockets appear to be confined to the zone between the surface 
 and the water-level, and to be dependent upon the results pro- 
 duced by the small cross-veins which encounter the main lodes. 
 In 1887 I had the pleasure of extracting, in two hours, a little 
 over 170 ounces of gold, worth about about $3000, from one 
 of these pockets. It was at the Rathgeb mine, near San An- 
 dreas, in Calaveras county. The main lode consisted of 5 to 8 
 ft. of massive "hungry-looking" quartz, the foot-wall of which 
 was a beautiful augite-schist and the hanging a hard diabase. 
 The water-level was 160 ft. below the surface. Down to this 
 point, the country was oxidized, the hanging-wall exhibiting 
 only slight alteration, while the schist of the foot-wall was soft- 
 ened and decomposed almost to a clay. This was traversed by 
 numerous small veins, which appeared to act as " feeders," 
 forming bunches of rich ore where they encountered the main 
 lode. At the 120-ft. level, south from the shaft, there were some 
 old workings ; and the examination of these led to the discovery 
 of a small seam, about one-sixteenth of an inch thick, filled 
 with red clay which carried a good deal of native gold, as was 
 proved by washing it in a pan. An experienced miner was put 
 to work, with instructions to follow this small streak. It varied 
 in thickness, and occasionally opened out into small lenticular 
 cavities, containing a clay in which the gold was distributed 
 like the raisins in a pudding. Each of these " pockets " yielded 
 several hundred dollars' worth of gold. At length the streak 
 widened to 6 or 8 inches of quartz, lined with clay. The 
 amount of red clay commenced to increase ; coarse gold be- 
 came more frequent ; and a big discovery was hourly expected. 
 It was finally made. The vein suddenly became faulted, and 
 at the place of faulting there was a soft, spong, wiry mass of 
 gold and clay more gold than clay. The first handful I broke, 
 
18 
 
 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 while yet the stope was thick with powder-smoke, contained 
 three ounces of gold. Within the next two hours this pocket 
 gave us $3000, and during the following week it yielded over 
 
 FIG. 2. 
 
 CROSS SEAM 
 
 OCCURRENCE OF A 'POCKET.' 
 
 $20,000, an amount which was obtained at a total cost of less 
 than $200. When it had been worked out, it was easy to ob- 
 serve the conditions which determined its occurrence at this 
 place, as Fig. 2 will explain. The vein, AC, had been faulted 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 19 
 
 about its own width, namely, 10 inches, by a small cross-seam, 
 DE, and at this intersection, B, the pocket lay. The gold was 
 spongy and was intermixed with quartz. The clay which pene- 
 trated the whole mass was partly red and ochreous, and partly 
 a gray gelatinous material. In the quartz, and associated with 
 the gold, there were acicular black crystals of pitch-blende 
 (uraninite), together with uranium ochre. This association of 
 gold with uranium is uncommon. 
 
 New Zealand. Intersections which coincide with enrichments 
 form a notable characteristic of the Hauraki gold-field* in the 
 north island of 2Tew Zealand. In this district the occurrence 
 of patches of native gold is an important feature of the regular 
 mining operations. When I was there, in 1891, each stamp- 
 mill had its " specimen-stamp," a single stamp working in a 
 separate mortar, and employed solely for the treatment of speci- 
 men-ore. These rich patches occur at the places where the 
 u reefs " or lodes cross bands of flinty quartz. The latter are 
 known among the miners as " flinties." They vary in thick- 
 ness from a few inches to mere threads of chalcedonic quartz. 
 They are barren in themselves, but have a favorable effect on 
 the gold-veins. The latter are also intersected by cross-veins, 
 producing an enrichment similar to that caused by the " flint- 
 ies." Fig. 3 is a sketch of one of these intersections, as seen 
 by me in the Moanataeri mine. The lode, AB, consists of 
 a series of small seams of quartz, conforming to the struc- 
 tural lines of the enclosing country, which is hornblende-ande- 
 site. The cross-vein, CD, is a band of soft gray decomposed 
 rock, which also carries a number of small quartz-seams, but 
 only near its crossing with the main lode, AB. The line 
 of CD is parallel to a large fault, to be seen elsewhere in the 
 mine-workings. The " leaders," or quartz-seams, in AB are 
 gold-bearing, and exhibit marked enrichment at the intersec- 
 tion with CD. 
 
 The prevailing formation of this mining district is an ande- 
 site, which is traversed by soft bands of decomposition, called 
 " sandstone " by the miners. The latter, when penetrated by 
 quartz-seamSj are favorable to the finding of ore. The gold- 
 occurrence is essentially sporadic and dependent upon local en- 
 
 * It is also known as the Thames district. 
 
20 
 
 THE FORMATION OP BONANZAS IN GOLD-VEINS. 
 
 richments, such as have been described. The district is sur- 
 rounded by thermal springs, and is near the well-known volcanic 
 region of Tarawera, which was active in 1884. The mine- 
 waters are heavily mineralized and very acid, so that the metal 
 screens used in the mills are quickly corroded. Tellurides and 
 selenides of gold have been detected in the ores ; but the pre- 
 
 FIG. 3. 
 
 ENRICHMENT AT INTERSECTION MOANATAERI MINE, NEW ZEALAND. 
 
 cious metal is usually found native and in coarse particles, 
 which are frequently coated with native arsenic. The district 
 is one which, I think, if thoroughly examined, would afford 
 many suggestions regarding ore-deposition.* 
 
 * The best description which has come under my notice is " The Geology of 
 the Thames Goldfield," by James Park, read before the Auckland Institute, 1894. 
 
 See also " On the Kocks of the Hauraki Goldfields," by F. W. Hutton, Proe. 
 Austral. Assn. Adv. Sci., 1888 ; and J. R. Don, " The Genesis of Certain Auriferous 
 Lodes," Trans., xxvii., 584-589. 
 
THE FORMATION OF BONANZAS IN GOLD-VEINS. 21 
 
 CONCLUDING REMARKS. 
 
 It is to be hoped that the recent recognition of the agencies 
 which bring about the formation of enrichments by surface- 
 waters will not cause too violent a swing in the direction of a 
 sweeping advocacy of the general efficiency of descending 
 solutions to form ore-bodies. The study of the problems of 
 ore-occurrence has been hindered in the past by such reactions 
 from one extreme view to its opposite. Therefore, in conclud- 
 ing this contribution to the discussion of the results produced 
 by descending surface-waters, I would emphasize the wider 
 agency of ascending solutions in forming the ore-masses amid 
 which such secondary enrichments are occasionally found. It 
 is agreed that the sulphide-ores are primarily deposited from 
 ascending waters ; it is also likely that such a result is repeated. 
 A region once subjected to fracturing, which has permitted 
 the subsequent passage of mineral-bearing solutions, is likely, 
 at a later period, to be subjected to a repetition of these activi- 
 ties. The geological history of many mining regions gives 
 clear evidence of a repeated disturbance of structure. This is 
 indicated by the existence of several systems of fractures 
 crossing each other, the later ones dislocating the earlier. It 
 is probable that each period was marked by mineralization, the 
 character of which may have varied. The banded arrange- 
 ment of the lodes of certain districts, such as Freiberg, Rico 
 and Butte, suggests this. Enrichment may have been caused 
 by mere addition ; the introduction of other metals may have 
 changed the average composition of the ore in the lode so that 
 it is now extremely valuable, whereas before it may have had 
 no economic importance ; a silver-ingredient may^ have been 
 added to the gold-contents, or the addition of copper may have 
 made a deposit doubly valuable by improving its metallurgical 
 character. I hope the present discussion on ore-deposition will 
 prove as inspiring to further investigation as did Posepny's 
 paper of 1893, and that data concerning the possible secondary 
 enrichment of sulphide-ores by the repetition of ascending 
 solutions will be sought for. There is nothing like a working 
 theory to sharpen the observation. Theories do not alter facts, 
 but they often lead us to tind new ones. 
 
 In cordially welcoming the splendid treatise of Professor 
 Van Hise I need make no reservation. When Posepny made 
 
22 THE FORMATION OF BONANZAS IN GOLD-VEINS. 
 
 clear the essential character of the upper or " vadose " water- 
 circulation, he did us a great service ; and when he combated 
 " lateral secretion " he overthrew a very narrow interpretation 
 of ore-formation, which was calculated to hinder seriously our 
 progress toward the understanding of these difficult problems. 
 But Posepny was carried so far by his controversy with Sand- 
 berger as to over-emphasize the sole agency of ascending cur- 
 rents. At that time, in 1893, I demurred to this extreme view 
 and said, " the word circulation is the key to the whole matter.' 7 * 
 By this I meant that the entire underground water-circulation 
 played a part in the formation of ore, and that to swing from 
 one portion of that circulation to another, restricting oneself to 
 the agency of either, would not (so it seemed to me from ex- 
 perience in the mines) solve the problem. 
 
 It does not appear to me that Professor Van Hise has erred by 
 exaggerating any particular view of the subject. His elucida- 
 tion of the water-circulation as a complete system is based on a 
 broad conception of the whole matter. Of course, in indicating 
 the work done by an agency hitherto largely overlooked, he was 
 compelled to place some emphasis on certain neglected features 
 of the descending portion of the water-circulation, and thus to 
 give it some prominence in his masterly analysis. This makes 
 the consideration of the question of secondary enrichments by 
 surface-waters one of the most valuable parts of his treatise. 
 
 Regarding this question of secondary enrichment, it is to be 
 pointed out that all ore-deposits are " secondary," the ore as 
 found by the miner being merely the last term of a series of 
 solutions and precipitations through which its substance has 
 passed in a ^constant shifting due to the underground water- 
 circulation. However, the last stage of the journey is the only 
 one of immediate importance to the miner ; and the determi- 
 nation of the causes which brought it there is, to him, far the 
 most interesting aspect of the general inquiry. That Mr. Em- 
 mons should also have investigated and illuminated the 
 problem is matter of much pleasure to a great many, engaged 
 in mining throughout the West, to whom his geological con- 
 tributions have always seemed to possess a practical bearing 
 and value unfortunately not always found in scientific descrip- 
 tions of geological phenomena. 
 
 * Trans., xxiv., 950. 
 
U. C. BERKELEY LIBRARIES 
 
 UNIVERSITY OF CALIFORNIA LIBRARY