HYDRAULIC AND PLACER MINING ISrlS BY EUGENE B. WILSON THIRD EDITION, THOROUGHLY REVISED TOTAL ISSUE FIVE THOUSAND NEW YORK JOHN WILEY & SONS, INC. LONDON : CHAPMAN & HALL, LIMITED 1918 w Copyright, 1898, 1907, 1918 BY EUGENE B. WILSON Stanhope ipress F. H. GILSON COMPANY BOSTON, U.S.A. PREFACE TO THIRD EDITION THE first edition of " Hydraulic and Placer Mining " was written to meet a demand for an elementary treatise on the subject. Ten years later the book was revised, and now, another ten years having elapsed, a third edition is published with addi- tional information that further widens its scope and it is hoped its usefulness. Naturally new ideas' have advanced the first principles, and we find the Giant has expanded from its original field, that of disintegrating gold-bearing gravel beds, to dislodging different kinds of minerals and materials from their resting places. The use of streams of water in stripping or washing away the cover from different mineral deposits goes to show that the conservation of energy applies to brains as well as all things else. Within the past ten years veritable mountains of wasted coal that covered the landscape in the vicinity of anthracite mines in northeastern Pennsylvania have disappeared, washed away by streams of water issuing from nozzles. Much of this coal has been reclaimed, while the remainder has gone into the mines to help fill the ever-increasing excavations. The possible uses of streams of water in mining operations are on the increase ; in fact where natural pressure is unavail- able artificial pressure developed by the aid of high-speed centrifugal pumps is brought into use. iii 382J69 iv PREFACE The writer wishes to express his obligations to President H. C. Parmelee of the Colorado School of Mines and to Professor L. C. Hills for permitting the use of the article on Graphical Hydraulics; also to John Powers Hutchins who so critically read the second edition that he assisted in clearing up typographical errors. Kindly criticism is always appreciated by an author, be- cause he is sure of the other kind, which however is of ten- tunes helpful. Many practical men have requested by letter that some of the text in the second edition be explained. Whenever such letters show that the writer is striving to increase his knowl- edge and hence usefulness the author takes pleasure in an- swering them. E. B. WILSON. SCRANTON, PA. PREFACE TO SECOND EDITION. THE demand for the first edition of this work, and the great activity developed in placer mining, due in a large measure to the great returns from this species of work, as well as the very substantial profit accruing to the exploitation of the placers, has led the author to present this second edition. There have also been many new methods for catching the free gold, as well as great improvements in the machinery for handling the material, and in the application of new machinery to placers where unusual difficulties were encoun- tered in working them. All these considerations have led the author to issue the new edition, which in his opinion, brings this work abreast of the latest improvements in this industry. He desires to acknowledge his indebtedness to the various technical jour- nals, as well as to the engineers whose names appear in the text. The manner in which this subject is presented, the author thinks, will appeal not only to those engaged in placer min- ing, but to those who desire to get the latest ideas relating to this industry. THE AUTHOR. CONTENTS. CHAPTER I. GEOLOGY OF PLACER DEPOSITS, PLACER PROSPECTING, PLACER TESTING, PLACER VALUING i CHAPTER II. HYDRAULIC MINING, SALT MINING, BOOMING, CULM MINING . 50 CHAPTER III. DEVELOPMENT OF PLACER MINING: PAN, ROCKER, SLUICING, LONG TOM, SLUICE BOXES, TRANSPORTING POWER OF WATER, FLOW OF WATER IN SLUICE BOXES, TRANSPORTING POWER OF WATER, FLOW OF WATER IN SLUICE BOXES, GRADE ........ 61 CHAPTER IV. RIFFLES, UNDERCURRENTS, HUNGARIAN RIFFLES, DUMP .... 136 CHAPTER V. WATER SUPPLY, MINER'S INCH, WEIRS, FLUMES 152 CHAPTER VI. PIPE LINES, FLOW OF WATER THROUGH PIPES, STRENGTH OF PIPES, PIPE BENDS, WATER GATES, AIR VALVES, PRESSURE Box, DITCH LINES, FLOW OF WATER IN DITCHES, SIPHONS ... 174 CHAPTER VII. GIANTS AND HYDRAULIC ELEVATORS 210 CHAPTER VIII. PLACER MINING INVESTMENTS, COST OF HYDRAULICKING, THE CLEAN-UP, RETORTING THE MERCURY, DRIFT MINING, BLAST- ING GRAVEL BANKS, MINING IN ALASKA 227 vii Vlll CONTENTS PAGE CHAPTER IX. MINING IN NORTH CAROLINA, LOG WASHER, STEAM SHOVEL MIN- ING, CABLEWAY MINING 249 CHAPTER X. DREDGING, DESCRIPTION or DREDGES 264 CHAPTER XI. TRACTION DREDGES, DRY PLACER MINING MACHINES, DRY WASHERS 297 CHAPTER XII. BLACK SANDS 3 J 4 CHAPTER XIII. UNITED STATES MINE LAWS 333 CHAPTER XIV. CANADIAN YUKON LAWS 348 CHAPTER XV. INFORMATION IN HYDRAULICS 3 6 & HYDRAULIC AND PLACER MINING CHAPTER I. GEOLOGY OF PLACER DEPOSITS. THE term placer is defined as a place where surface depositions are washed for the valuable minerals, gold, tin, tungsten gems, etc. Placer mining is defined as washing surface depositions for gold. The gold found in alluvial deposits is in the metallic state, and in all probability was derived from the dis- integration of gold-bearing rocks and veins. The chemical and mechanical processes that freed the gold from the rocks with which it was associated are numerous and sometimes obscure, although it is obvious that the elements in combination with water and ice have been the chief factors in tearing rocks apart and concen- trating the gold. Most placers are composed of quartz pebbles, sand, rocks of various descriptions and sizes, and clay. The gold forms a very small portion of the mass, while quartz sand, with garnets and black sand, the latter composed of magnetite, ilmenite, and hornblende, make up another portion of the mass. The disintegration of rocks is occurring continually, and has been for ages. The lighter particles are carried away by wind and water, and the heavier are left. While 2 GEOLOGY OF FLACER DEPOSITS the so-called elements - y/ind, heat, cold and water have been the chief causes of disintegration, there are indications that glaciers have played an important part in the erosion of rocks, a^ they moved from higher to lower levels, particularly in the more northern latitudes. Water has been the chief factor in the formation and concentration of placers, although the other elements have assisted. The San Juan River extends from North Bloomfield to Nevada City, California. This was an ancient and by some called a tertiary river, that cut a natural chan- nel through the bed rock. In time the channel became partially filled with wash dirt and gravel that contained gold, until the deposits reached a thickness of 500 feet. When the upheaval occurred that formed the Sierra Mountains the river bed was raised high above its origi- nal position. Lava flows later followed the upheaval, filled the ancient river channel, and covered the placer in the river bottom to a depth of from 200 to 400 feet. As the width of this river varies from one to one and a half miles, it must have been an important water course in its time. The present river follows the course of the ancient river; however, as this is but one of many ancient rivers it is reasonable to expect that some of the modern rivers would cut through the lava capping of the old placers to bed rock and form modern placers. This is the case, so that two kinds of mining are needed to extract the gold from the two differently situated ancient placers. Where the ancient river beds have been eroded by modern rivers cutting across the overlying capping of lava, secondary ANCIENT SEA-BEACHES 3 placers have been formed which also are a source of gold. The composition of the gravels in these ancient river channels represents nearly every rock in the vicinity, such as diabase, diorite, serpentine, slate, granite, syenite, and quartz. The lowest gravels in some placers have a blue tint, and are termed the "blue lead" since in this locality the richest ground is found above bed- rock. The depth of the "pay streak" or rich gravel, is from 2 to 6 feet and is said to carry from $2.50 to $13.00 per cubic yard. From data furnished by writers, it would appear as if ice rivers were the factors that disintegrated and transported the gold to those places where it is now found in Siberia and the Klondike. Between Cape Nome and Point Rodney, Alaska, for a distance of 25 miles, there is an ancient sea-beach that extends back from the ocean a distance of 2500 feet. It contains a placer deposit, with the pay streak 20 feet above sea level, and from 12 to 32 feet below the surface. From the westerly base of Cape Nome, gravel terraces or ancient beaches rise gently to the north and west, forming ridges that extend 4 or 5 miles inland, until their highest elevation, 250 feet, is attained. Be- tween the ridges there are broad valleys that contain tundra or arctic swamps. Within the last ten years the tundra have been pros- pected and found to contain very rich placer ground. The pay streak is situated just above bed rock at depths varying from 60 to 130 feet. The ground is as a rule frozen to bed rock, but here and there soft places are 4 GEOLOGY OF PLACER DEPOSITS encountered, due to some underground circulation of salt water. The bed rock is sedimentary, and contains gold, ruby and black sands that have been cemented in mud by quartz solutions. Above the bed rock is ruby, magnetite and quartz sand in fairly evenly sized grains, with some quartz pebbles and gold in flakes. This is the pay streak, and above it to the surface are alternate layers of rounded beach gravel and gray sands. The pay streak is so marvelously rich in the tundra mines of Little Creek on the Seward Peninsula, it is difficult to account for its .origin. One theory is that glacial rivers formed the placers by pushing ahead of them the gold and gravel they ground from the rocks they passed over. Another theory is that the receding waters of the Arctic Ocean and possibly subsequent upheavals produced the placers and the beaches. The third theory is that the ocean waves pounded the coast rocks to pieces and concentrated the gold. In the eastern United States along the coast, glacial action so denuded the rocks that no placers are reported north of Maryland. From Maryland to Georgia, to the east of the Appalachian Mountains, placers are found. In several localities in Virginia gold is found in clayey, sandy soil, containing also quartz pebbles. The gold vein is not far from such deposits. In North Carolina, the gold is found in decomposed Cambrian schists ; and in chemically altered rocks. In such places the rock contained quartz stringers that carried the gold. In some of the brooks that have worn away these deposits MOTHER LODES 5 free gold is found, but the placer itself has not been disturbed by either glacial or water erosion. In the early days it was assumed that all placers if traced up would lead to the discovery of their source or the " mother lode," and that the lode would prove infinitely richer than the placers. The lode may fre- quently be found, but nine times out of ten it does not contain free gold in anything like the proportion or the size of grains that the placers would indicate. Original rocks are found that will not show gold to the naked eye, and at times not with a magnifying glass, yet the placers from these rocks contain both fine and coarse gold. The Edith mine in Catawba County, North Carolina, is an instance where gold is found in nuggets through the disintegrated rocks, there being no vein present. The Sawyer mine in Randolph County, North Carolina, and the M orris ville mine in Virginia are instances where the gold is so fine it cannot be seen with the eye, yet both have placers that show coarse as well as fine gold. The Breckenridge, Colorado, placers, have produced considerable wire gold, and the mother lode is traced with reasonable certainty; yet the vein has never paid when worked. The gold ore that took the prize at the Centennial came from Louisa County, Virginia, yet the placers in that vicinity, or those near the Cabin John mine, Mary- land, do not show such large nuggets. From what has been said it is difficult to tell from the size of placer nuggets just what kind of gold will be found in the mother lode. Gold was discovered in California Gulch, 6 GEOLOGY OF PLACER DEPOSITS Colorado, as placer, but when traced to Leadville at the head of the Gulch, the greater part of the valuable deposits were silver-lead. The richer placers of California did not lead to im- portant quartz lodes, and the Comstock lode, although rich in silver and gold, did not show gold in the vein. The history of placer mining is such that to trace up a placer and find a rich free milling-ledge is not the rule, but generally the exception. Rich veins have been discovered where no traces of placer could be found, except in the grass roots directly over the vein, and again placers have been found where no vein existed. That gold should be found in paying quantities and in sizes from flour to nuggets in placers and not in the mother lode in similar sizes, seems mysterious, and, if some placer miners are to be believed "it grows." This latter statement miners will illustrate as follows: In 1875 California Gulch was washed and $20,000,000 in gold was recovered; when it was abandoned one could not make wages. Of course, some seeds were left, and in 1885 it was washed again and $5,000,000 recov- ered, the inference being that it grew. The explana- tion that possibly millions of tons of gold-bearing material were concentrated in that gulch by Nature, and that the second washing was only the leavings of the first, will not satisfy the miner, who will probably paraphrase Job and reply, "There are veins of silver; but the place for gold is where you find it." Assume that two small pieces of gold are in contact and resting on a rock, and again assume that water moves a fair-sized stone so that it strikes the gold and AREA OF PLACERS 7 welds the two pieces. This assumption is not unten- able if one will consider how easily the dentist welds gold when filling a tooth, and it may account for "gold growing." Water has in some instances carried the gold many miles down a sloping hard river bed, and eventually deposited it; in other instances the distance traveled has been short. Gold may move slowly down the sides of a mountain and be found in streaks parallel to the mountains trend. Placer deposits are found in narrow streaks or in wide belts, according to their location, the manner in which they were formed, and afterwards acted upon by Nature's forces. Gulch placers are necessarily narrow, old river beds are much wider, and in some cases where there have been upheavals and severe dynamic disturbances fol- lowed by torrents of water they are quite wide. The original placer may have been spread broadcast over an ancient sea or lake bottom that was afterwards raised by an upheaval and formed what is now known as a "dry placer," that is, a placer in a locality where there is no water. Dry placer areas are quite extensive, and are found in deserts and in some of the arid counties of New Mexico, Arizona, Nevada, Lower California, Mexico, Australia, and possibly India. Gold is not equally dis- tributed through a placer, owing to the current shifting when the placer was formed, for which reason one miner may be working in pay dirt while another a few feet away is not making wages. The miner of experience 8 GEOLOGY OF PLACER DEPOSITS is very cautious in following up his pay streak, and will dig to the right and left of a rich spot before going ahead. Gulch mining is particularly uncertain, and frequently the richest dirt is along the sides, and not in the center of the gulch. No one can with absolute satisfaction explain the various causes for the distribution of gold in placers, for which reason the ground must be systematically sampled. At times the gold will be uniformly distributed through the dirt, at other times it will be in bunches with barren dirt above and below, and in some cases it will be con- centrated in spots in a bench termed a pay streak. It has been found from grass roots to bed rock but in the majority of cases the richest deposits are in the latter situations. If there be depressions in the bed rock where gold can accumulate the pay streak may be very rich at times. Where bars were formed in ancient streams by eddies, the gravel may be very rich, hence the necessity for carefully following the pay streak in bench mining. The thickness of placers will vary from a few inches to several hundred feet, and where one deposit may hare but a single pay streak, another may have several. From what has been said the reader evidently under- stands that the composition of the placer dirt will vary in different localities. The easiest dirt to wash is sandy gravel. Hardpan, composed of gravel cemented with clay, is more difficult, for if wet it is hard to shovel, and if dry it is difficult to pick. Usually fine sand is not as rich as coarser sand, and to this may be attributed some of the failures in dredging river bars. PLACER PROSPECTING 9 The character of the gold found in placers is as dif- ferent as the placers. Coarse gold in nuggets is the easiest to recover, on account of its weight and shape. Flake gold is not so easy to save as nugget gold; how- ever, its weight will make it sink as soon as it is cleaned sufficiently to prevent the water moving it. Leaf gold resembles flake gold, but is much thinner and lighter and consequently will sink with difficulty, muddy water seemingly having sufficient buoyancy to carry it away. Flour gold is very fine gold, that may make the assay of a deposit run high; at the same time it is difficult to save, and very often it cannot be saved by the hydraulic methods practiced for nugget gold. The black sands that are usually found with placer gold carry consider- able gold and frequently platinum; therefore, wherever it is possible they should be saved. In Trinity County, California, there are both ancient and present river placer deposits, the latter mostly de- rived from the former, through the natural changes in the rocks brought about by time and the elements. One of the ancient river channels extends from a few miles north of Trinity Center southwesterly to Junction City, a distance of about 30 miles. The bed rock of this channel is several hundred feet higher than the bed rock of the present Trinity River and the gravel is sometimes 500 feet thick, where it has not been affected by erosion. Gold is scattered through the entire mass of alluvium, although as in present rivers it is more abundant in some places than in others. To illustrate the conditions prevailing, assume that Fig. i represents the cross-section of the country across 10 GEOLOGY OF PLACER DEPOSITS several canons or ravines; then it will be possible to understand the method of reaching the ancient river bed by means of tunnels, H, driven at right angles to the course. The original position of the land is represented FIG. i. by the horizontal line A A; and it is probable that the rocks carried gold. In time this land was eroded and assumed the surface undulations represented by the dotted line ABA. In the course of time, possibly many centuries, the surface rocks were washed down from the hills into the valley B which also formed a river channel. During the times of high water the rocks in the channel were disintegrated by water moving them and causing them to strike against other rocks until the gold they contained was freed, and naturally being heavier and in smaller particles than the rock, it settled to the bottom of the channel. It is probable that some of the gold traveled long distances before it reached the place where it is now lodged, in fact there are evidences of gold having been carried several hundred miles before finding a rest- ing place. In California after the rivers had cut their way through the rocks there was an upheaval (pre- TERTIARY RIVER PLACERS II sumably in Tertiary times), followed by a basaltic lava flow which first filled the ancient river channels, and some- times capped the hills above them. In the epochs fol- lowing the lava flow, that being able to resist erosion better than the shattered country rock, new channels formed as at EE shown by the heavy lines. These new rivers may be 1000 or more feet lower than the lava cap in some places, and then again the present river course may be above the ancient river bed, as in Tasmania and the Klamath River District, California. In still later periods the new river beds may have channels cut in them, when bench deposits such as are shown at G will be found. The rim rock of the rivers is the shore line or country rock each side of the river channel, and where there are gulches at an angle to the channel, tunnels H may be driven to reach the channel at B. In Fig. i, C represents the lava cap, and D the gravel deposit in the ancient river; G represents a channel cut in the present river bed so as to form the bench de- posits mentioned. According to the United States Revised Statutes any deposit of minerals not found in place in veins in rock are placers, therefore the descriptive geology of the stanniferous deposits of Tasmania furnished by Edward Edwards in his Paper on Hydraulic Mining is abstracted in part, first because the geology is somewhat similar to that of California, and secondly because these tin deposits are worked by hydraulic mining. 1 The country rock is granite which contains small tin 1 Mines and Minerals. 12 GEOLOGY OF PLACER DEPOSITS veins, or large low-grade deposits of tin in metamorphosed granite bounded by unaltered barren granite. The altered granite is coarse and probably would come under the head of greisen. In addition to cassiterite, Sn0 2 , it contains other minerals. The placer deposit having been derived from the greisen naturally contains all the associated minerals in that rock which includes a little gold and petrified wood; but the mineral sought and recovered is the tin oxide. If any other minerals are saved, they are by-products. While basaltic flows cov- ered the ancient river channels they seem not to have been so copious as those of California as they do not cover the surrounding hills. In Fig. 2 is shown how the basaltic flows a covered the ancient river gravel b and protected it from erosion. FIG. 2. Evidently the eruptions were not confined to one out- burst, for at a drift accumulated between the lava layers. This drift also proves that the river occupied its course after the first eruption, but that after the final lava flow the river and its tributaries were displaced and forced into other channels as at c. In most cases these channels were to one side of the lava and commencing at the un- altered country rock a new channel was started as at/, Fig. 3, on the assumption that e was the level of the basalt. TERTIARY RIVER PLACERS 13 The Ringaroom River which it is believed had its commencement at / gradually eroded the lava, but not the hard country granite rock to so great an extent, until it reached its present position c in Fig. 3. It will be noticed that the river has reached the gravel deposit FIG. 3. and moved it to places where later banks have been made, some as high as 100 feet, and it is these banks of alluvial material on which placer mining is practiced. Those portions of the deposits below river level are worked by dredges. Waters percolating through the altered basalt leached out iron and this converted the drift below into a hard cement of a red-brown color, the same in appearance as the weathered basalt. The remainder of the river drift consists of white sand and granite boulders with here and there layers of white clay derived from the feldspar of the granite. This clay would indicate from its presence in the wash that there were periods of tranquil sedimentation which assumption is substantiated by the absence of tin oxide and other heavy minerals. 14 GEOLOGY OF PLACER DEPOSITS Tin oxide or cassiterite has a density of 6.4 to 6.9 according to its purity, and because of being much heavier than more common minerals it sinks and remains motionless while the others are swept along by the flowing river. The oxide is found scattered through the whole gravel deposit, and in nearly horizontal layers although as a rule the drift is richest along the bottom of the river bed; however the quantity varies both across and along the deposit. The ore is fairly uniform in size and is of excellent quality, the concentrates assaying 75 per cent tin which is the equivalent of 95 per cent cassiterite. Waldmer Lindgren of the United States Geological Survey studied the Tertiary placer deposits of the Sierra Nevada mountains in California and presented his find- ings in Professional Paper No. 72 of the Survey. Be- cause of the difficulty of obtaining this paper at this time, at least by many, the following is abstracted. "A basement of closely folded Paleozoic and Meso- zoic sedimentary rocks was intruded and elevated near the close of the Mesozoic Period by granitic magmas. This was followed closely by the introduction of veins and seams of gold bearing quartz. The resulting high- land was planed down by erosion in early cretaceous times. When reduced to gentle outlines deep rock decay took place and much gold was freed from its matrix. Renewed uplifts quickened erosion which concentrated the loosened gold along definite channels. During this period of most active gold concentration faulting move- ments with downthrow on the east side, transformed an TERTIARY RIVER PLACERS 15 approximately symmetrical range to a monoclinal one with steep easterly slope. Towards the end of the Terti- ary Period long inactive volcanic forces became active. Rhyolite flows filled the valleys, covered the auriferous gravels and outlined new stream courses in the old val- leys. Renewed disturbance began along the scarcely healed eastern breaks resulting in a westward tilting of the main blocks. This encouraged deeper cutting by the streams which repeatedly crossed their old courses, and concentration of gold proceeded under less favorable torrential conditions. Volcanoes sent out immense quantities of tuff, filling many valleys to their rims and converting almost all of the northern Sierra into a desolate, steaming expanse of mud. Storm waters now began the canon cutting epoch, with the amazing results seen to-day. In many places the old rivers of the Tertiary were exposed and cross sections of their valleys are now seen on the steep slopes of the canons high above the present river beds: although large stretches of the old channels remained secure below their thick blanket of volcanic mud. Gold is still contained in the Tertiary river channels, miles of them are still unworked, but the problem is how to extract without damage to other property and how to reduce -the cost of drift mining. The gold of the larger channels is about the size of flaxseed, although large nuggets are occasionally found, that from Carson Hill weighing 195 pounds Troy. Only recently one was taken from the Emma Mine near Magalia that weighed 50 ounces. The general channels yield from $70 to $500 to the lineal foot, which may be compared with $100 per 16 GEOLOGY OF PLACER DEPOSITS foot at Nome, Alaska, $350 a foot in White Channel in the Klondike, and $440 to $1293 in the Berry drift mine in Australia." Hydraulicking on the tributaries of the Sacramento River in California was stopped by the courts previous to 1893, owing to the great quantity of dirt which was carried down the rivers and deposited as silt on the farm lands. The Klamath River field is now we believe the only district in California where hydraulicking is prac- ticed. The Caminette Act of 1893 which demanded the impounding of debris from the placers of the San Joaquin and Sacramento valleys, does not affect any other part of the state as most rivers flow directly to the sea. The deposit being mined is an ancient channel of the Klamath River which had a flow nearly parallel to the present river, but at considerably less elevation relative to the sea level. The old channel varies in width from 100 to 600 feet, and possibly more, for the channel seems to be widening as work progresses. Granite and schists are the prevailing country rocks with the bed rock a hard schist rough and water worn with soft shale streaks at intervals. The shale being tilted forms an excellent riffle for gold moving along the bottom. In cleaning this shale it is not stripped bare by the giant because that breaks the rock and the gold sinks into the cracks made. Men therefore pick the shale at right angles to the dip to a depth of about two feet, the object being to prevent the gold from sinking deeper as would be the case if the picking were done parallel to the dip. The hard slate bed rock is pipe-washed clean, the crevices only being cleaned by hand. At the contact of DRY PLACERS 17 the schist and shale there is a blue clay which if not broken to mud will carry gold through the sluices and prevent its entering the riffles. The bed rock is on an average about 20 feet below the surface, and although the pay streak has an average thickness of 10 feet the best ground is within 5 feet of the bed rock. It has been noted that the higher the gold is from bed rock the lighter and purer it is. The pay-streak gravel, dark blue in color, consists of a mixture of heavy water-rounded rocks and wash material. Owing to the sulphides in the country rocks the water coming through the cracks in bed rock is very corrosive, being charged with arsenic and iron sulphates in solution. When this water comes in contact with the metal in the pipes it quickly corrodes them unless they are painted as in other places mentioned. Dry Placers. Dry placers have been mentioned as occupying large areas in the southwestern states and Mexico. These were formed by rivers evidently of the Tertiary period or later, which flowed southwest from the Rocky and south from the Sierra mountains. The ground in which the placers are found is not deep and is composed of sandy clay. South from the Pima Desert in Arizona there extends a large area of this dry placer material which in Sonora, Mexico, is called the Altar District. In an area between the Magdalena River and the Gulf of California there is about 9600 square miles of dry placer material which is brought to the attention of the public every few years by the man who has invented a new machine to treat this ground. i8 GEOLOGY OF PLACER DEPOSITS These dry placers were discovered by Spanish soldiers in 1779 and rediscovered in 1840, again in 1892 and more recently in 1908; in the meantime they were never lost sight of from the time of their earliest discovery and are worked off and on by the native Indians. While as a rule these deposits are not deep, rich ground has been found when digging wells to a depth of 90 feet. The gold is found in clay that accompanies cement gravel and to disintegrate this material and free the gold with- out the aid of water is a problem which inventors have had in mind many years ; therefore when a new machine is invented for the purpose the placers are rediscovered. Unfortunately dry placer machines, except small ones worked by hand, require more or less water; even for the gas or oil engine used for power and consequently they have not yet come into general use. The writer believes that water can be found by digging wells at almost any place in the southwest provided a dry river bed or stream is the ground in which the well is sunk. This is somewhat substantiated by his experience in Arizona and the fact that between hills in the Altar district where the drainage collects, well water is found at depths from 150 to 300 feet below the surface. The Altar and Magdalena Rivers, which are usually dry, sometimes have water flowing in their channels during the rainy season. It is also natural to suppose that there are underground watercourses along the ancient sea floor that flowed westward into the Gulf of California. The author makes these remarks because he believes that the first problem to solve in order to work these placers is that of water supply; even if it is not large PLACER PROSPECTING 19 and is alkali it will go a long way towards making these placers productive. There are so many places in the southwestern states where gold exists that this subject of location might be continued almost indefinitely. Some of them will be mentioned further on in this book. PLACER PROSPECTING. The prospector, in working upstream in his quest for gold, finds in panning tests some places richer in gold than others. If he can make money washing one of these pockets he is said to have " pay dirt." Although gold is dissemi- nated in some cases throughout the entire mass of gravel of a large placer deposit, nevertheless there are places where the gold is in greater abundance than in others. Early prospectors sought these enriched places and the present hydraulic miners find many indications in the way of abandoned drifts and old shafts mute evidence of the pocket miner's zealous hunt for wealth. The prospector with little money, his tools being limited to pick, pan and shovel, is unable to attack a deposit of this kind from the top where bed rock may be covered many feet with gravel; consequently having become familiar with the kind of material and rocks in the channel at some place where it is exposed he follows the rim-rock. When he finds a gulch or ravine at an angle to the ancient river he com- mences to drive from the gulch so as to tap the gravel bed with a drift. After he finds the gulch he pans the dirt upstream and 20 GEOLOGY OF PLACER DEPOSITS continues to do so until he comes to a place where he can attack the channel. Sometimes the lead he follows is so rich in gold he pays his way while searching; in other cases he may keep up the hunt, although he does not recover much gold, being buoyed by the hope of eventually finding a pocket. When the streams are comparatively large the task of following them to reach the ground is easy ; where how- ever the prospector has to carry dirt some distance to water in order to wash it the work becomes very difficult. Experienced prospectors looking for placers will pass by gold which on examination shows that it came from veins in recent times, as he knows from the appearance of the gold that the ground has little value. The distinguishing features are that vein gold is fine and angular, whereas placer gold is usually coarser and water-rounded. This experienced miner, by the use of judgment, is thus kept from following a false trace that comes from some vein in the country rock. The prospector having made a discovery is entitled to 20 acres of placer land, but he should be sure that the claim has not been staked previously or that he is not on some land grant before he does much work in develop- ing. It may be stated here that very many claims have been located by prospectors who worked them to some extent and obtained considerable gold from them. These claims are held by heirs or others at exorbitant prices, when the amount of money involved to work them successfully is considered in addition to the risk, for which reason they remain and are likely to remain idle indefinitely. WATER RIGHTS 21 There are two factors to hydraulicking fully as im- portant as the placer deposit, namely : a sufficient supply of water and a dumping ground; if these are lacking the deposit will, unless very rich and otherwise mined, prove unremunerative. The first consideration is water and for this purpose the owner of a claim is entitled to water rights under certain restrictions. Revised Stat- utes of the United States in Section 2339, provides that, " Whenever by priority of possession, rights to the use of water for mining, agriculture, manufacturing, or other purposes, have vested and accrued, and the same are recognized and acknowledged by local customs, laws, and decisions of courts, the possessors and owners of such vested rights shall be maintained and protected in the same; and right of way for the construction of ditches and canals for the purpose therein specified is acknowl- edged and confirmed; but whenever any person, in the construction of any ditch or canal, injures or damages the possession of any settler on the public domain the party committing the damage shall be liable to the party injured or damaged "; and Section 2340 provides " That all patents granted or pre-emption of homesteads allowed, shall be subject to any vested and accrued water rights, or rights to ditches and reservoirs used in connection with such water rights, as may have been acquired under, or recognized by the preceding section." State laws relating to water rights are also to be considered; for instance the California law requires the person making the appropriation to post a notice at the point of the intended diversion, stating thereon : i. That he claims the water there flowing to the 22 GEOLOGY OF PLACER DEPOSITS extent of ... miner's inches measured under a four-inch head. 2. The purpose for which it is claimed and the place of intended use. 3. The means by which he intends to divert it, the size of the flume, ditch, pipe, or aqueduct in which he intends to convey the water. Montana has a somewhat different law, consequently the claimant to water rights must familiarize himself with these state laws. The object in prospecting placers known to contain gold or other minerals is to estimate the probable quantity of earth that must be moved, its average value in min- erals sought, and from this data to calculate the money it is allowable to spend on development to make a profit on the investment. To estimate the quantity of gravel in a property contour surveys of the surface are required, together with the thickness of the dirt in a given area. The latter is found by putting down lines of boreholes at regular intervals from the surface to bed rock or by sink- ing shafts. To ensure that the holes reach bed rock and are not in a large boulder it is probably advisable to sink them at least 10 feet into bed rock. The driller can usually tell by feeling the drill rods whether his drill is in a boulder or bed rock; he is further guided by the depth of his hole relative to another in a similar line; however, the plan suggested may be advis- able because it becomes surer that no large rock is mis- leading the driller. If the pay streak is near bed rock and the drill hap- CALCULATING PLACER GROUND 23 pened to land on a large stone near bed rock the gold would not show, but even then there would be the satis- faction in knowing that the blank was probably due to the boulder and not because the place was barren. After the holes have been drilled their positions on the map are plotted accurately with reference to the con- tours mentioned. Where the bed rock is uneven either of the following methods may be used: 1. The area is divided by lines connecting adjacent boreholes thus forming squares. The depths of the holes and the areas of the squares are then used to calculate the volume of the gravel bed. The depth of the hole in feet is placed on the map as shown in Fig. 5. 2. In the second method contour lines are drawn at regular intervals of depth, the areas enclosed are then found with a planimeter, and the volume between every two adjacent contours is computed by multiplying the mean area by the contour interval. The use of prismoidal formulae, advocated by some engineers to replace the mean average method, is a re- finement generally not justified in this kind of work on account of the comparatively few points actually deter- mined, and the large amount of assumption needed in interpolating the remaining points and contour lines; further, as will be shown later on, the accuracy of the method has not proved more valuable than the mean average method explained in this text. The method of estimating the overburden by cross- sections used at some of the large placer mines is shown in Fig. 4, where a represents barren ground; 6, the gold- GEOLOGY OF PLACER DEPOSITS bearing gravel; c, a series of boreholes across the deposit from rim-rock to rim-rock or as far as the property ex- tends laterally; while the figures i, 2, 3, etc., represent the distances between boreholes. FIG. 4. From the data thus acquired and the surface levels a general idea of any cross-section is obtained, relative to both depth and volume of the cover and placer ground. The method of recording this data is shown in the fol- lowing table: Area. i 2 3 4 5 6 7 Elev. surface 316 312 2 O 327-4 307.4 293-4 34 14 142 334-2 303.7 276.7 57-5 27 106 340.7 303-0 261 .0 79-7 42 216 340.6 303-7 258-7 81.9 45 280 330.1 305-1 268.1 62 .0 37 350 328-318 307.3 282.3-318 45-7 25 200 Elev. top drift Elev. bedrock Depth of cover Depth of gravel. . . . Value of gold Borehole No Estimating the Value of Placers. Sampling placer deposits is important, because on the values obtained the profits of the plants will be based, and if the operation ESTIMATING PLACERS 25 is not properly performed in low-grade deposits, the value of a few cents per cubic yard may cause the loss of large sums of money. The methods followed in arriving at the value of a deposit are enumerated as face sampling; tunnel and drift sampling; borehole sam- pling; shaft sampling; bulk tests under working condi- tions. In general a test consists in obtaining a known quantity of the material; washing it to recover the gold; weighing the latter and multiplying this weight by the fineness of the gold value, which if taken at $18 per Troy ounce will approximate the value, however, as the fine- ness of gold varies in different deposits the actual value per ounce had better be determined by the Assayer. If the sample taken is small the dirt is panned; if larger a rocker may be used; or if quite large it is sluiced and by this means the returns will approximate what may be expected in actual working. Of the three methods, that of panning is probably the most accurate when done by an expert, but it is advis- able to treat the whole sample in any case, because smaller samples taken from larger ones nearly always underestimate the gold. Two troubles confront the man taking the sample: namely, the irregular dis- tribution of the gold, and ascertaining the true volume occupied by the sample when it is in the ground. The best method of arriving at the size of the sample is to make use of measures of known capacity and then make allowance for the increase in bulk. Different kinds of material differ in volume when broken according to the size of the pieces, therefore the surest way of arriving at a bulk factor is to carefully mark off a portion of the 26 GEOLOGY OF PLACER DEPOSITS ground and measure it in the solid, then after the exca- vation is made measure the broken ground in boxes whose capacity is known. When it is possible to drive a powder can into the dirt face, a fair sample will be had be- cause when withdrawn the can will retain the original volume cut. The dirt when tipped from the can is broken and remeasured and the increased bulk is then expressed as so much per cent of the original. The mean of several such determinations furnishes a factor that may be applied to large samples or bulk tests. The increase in bulk will vary from 20 per cent for fine material to 50 per cent for coarse material. Face sampling while having the advantage of cheapness is not apt to give accurate values because of the difficulty in taking a representative sample; the practice is followed, however, in preliminary work, and when care is practiced it furnishes a fair aver- age of the deposit; at least it will indicate the necessity for further, more accurate and expensive tests. One method followed in sampling a bank or face is to clean off the weathered exterior from the top to the bottom of the bed by making a cut two or three feet wide and sufficiently deep to reach fresh dirt. This precaution is taken because natural concentra- tion occurs at the surface. In case the bank is high some means for reaching the entire surface must be de- vised. Either a ladder may be lowered from the top or raised from the bottom to the place sampled, or possibly a series of side steps can be made along the bank. In the latter case close measurements must be taken hori- zontally to prevent the steps overlapping. This latter consideration arises from the tendency of SAMPLING PLACERS 27 gold to accumulate in layers and at about the same gen- eral horizon relative to bed rock. In comparison with the remainder of the deposit such streaks are rich, yet, being thin, to miss or to overlap them will give false values. After the face has been prepared the samples are taken from bed rock upwards by measuring off one foot in height and putting in a small wooden peg as a marker for the next sample. The pan is held at the bottom of the place being sampled and the material, broken from the bed by a small pole pick, falls into the pan. The sample should be taken up and down the first foot section in straight lines and to an equal depth, going around stones over three inches in diameter or which do not work loose from the face. Owing to the edge of the pan being circular and the face generally more or less inclined the pan be- comes heavy if large and the dirt is apt to miss the pan, for which reason some one must hold the pan and it is also advisable to have a funnel with one side flattened to go against the bank while the spout directs the dirt to the center of the pan. This spout may have as large a diameter as three inches, to catch any large stones that may fall from the bank cut, for if such stones fall into the pan they dislodge dirt and sometimes cause the con- tents to spill. Material broken at a face 2 ft. X i ft. X 2\ in. deep will occupy a space say \ cubic feet or about i\ times what a pan 16 X 10 X 2\ in. high will hold. It may be advisable therefore to use a canvas basket for this kind of work as it will lessen the labor and furnish more ac- curate data on the volume of the sample. The number of pans filled evenly with the top that will 28 GEOLOGY OF PLACER DEPOSITS constitute a cubic yard in place varies with the degree of coarseness of the dirt; for instance, where one cubic yard of gravel will fill 70 pans, one cubic yard of gravel in another bench will possibly fill 150 pans evenly with the top. It may be understood from this that the factor for measuring by the pan is of even more importance than where measures are made in larger bulks; however, estimations are frequently made by pans. After the gravel is broken from the face for the length of one foot, it is carried to water and panned. If the gold is coarse the number of pieces are counted, but where fine this is im- possible and the gold with the accompanying black sand is saved. When the prices are counted, the position of the sample is recorded and its bulk estimation as well. The next foot of ground in the face is sampled in the same way and so upwards until the top is reached. If the bank is fairly uniform the gold from each successive foot may be placed in a small vessel for weighing provided it is so coarse it may be separated from the dirt in the pan; on the contrary, if it is so fine that it cannot be separated it is collected with mercury. If the gold and accompanying black sand were assayed, the value of the ground as a placer could not be estimated, for black sand frequently contains considerable gold that can only be recovered by furnace treatment. If the ground forming the bank is in layers of different kinds of material each layer should be kept separate so that each may be valued. To calculate the sample and its value the gold is cleaned, weighed and the weight multiplied by the fine- ness of the gold estimated in cents. In this connection it may be stated that some make ESTIMATING GOLD IN PLACERS 29 use of the gram and others make use of the grain in cal- culations. The gram weighs 15.432 grains. The value in cents is next divided by the number of pans washed and the bulk of the sample estimated in cubic yards, which will give in the aggregate the value of the bank in cents per cubic yard. To illustrate this method, assume the height of the gravel deposit to be 35 feet and that it is divided into three well-defined stratum 10, 14 and n feet thick. From the lo-foot stratum 10 pans were taken and the broken material averaged 70 pans to the yard. The 14- foot stratum required but 40 pans to the yard and the 1 1 -foot stratum 70 pans per yard. The gold recovered when weighed and estimated was found to be 871 fine and worth $18 per ounce or 0.0578 cent per milligram. With this data the following table is computed. Stratum. Mg. Gold. Value in Cents. Pan Value in Cents. Value per Cubic Yard in Cents. Ft. 10 14 ii 30-4 160.0 64.0 1.76 9-25 3-7o 0.176 0.660 0.180 0.176 X 70 = 12.3 0.660 X 40 = 26.4 0.180 X 70 = 12.6 To obtain the bank value the results are averaged by taking into account the value and thickness of the strata: Thus I0 x 12.3 123.0 14 X 26.4 369.6 ii X 12.6 138.6 35 631.2 631.2 -T- 35 = 18.03 cents per cubic yard as the average value of the bank. 30 GEOLOGY OF PLACER DEPOSITS The method of testing described is applicable to banks and stopes in drift mines where the exposure is fairly steep, particularly where the gold is in more than one layer of gravel. A somewhat similar though more exact method is that of measured cuts, where the gold contained in a known volume of gravel measured in place is ascertained by careful washing. Since the gold obtained is from the gravel in place the uncertain estimate of the expansion of broken material is obviated. In this case the bank to be sampled is cleaned as in the pan method from top to bottom, the width being such that one foot at least is left each side of the proposed cut. Sample cutting com- mences at bed rock, then by working a predetermined width and depth it proceeds upwards. Usually a cut 2 feet wide and i| feet deep is taken by first picking from the center line of the cut and when approaching within three inches of the sides care is taken to trim to the exact width of two feet, and also reach the exact depth. A template will obtain accuracy in width and depth but a center line should be used to keep the cut straight. When collecting a sample in this way a canvas sheet is spread at the bottom of the cut to prevent the gravel scattering and it may be advisable to place a canvas over the cut to confine the broken material within the cut, thus forming a sort of chute. If it is impossible to make a continuous cut from the top to the bottom then the engineer will have to devise some means whereby he can obtain samples which would approximate such a cut, taking care not to omit or to overlap any part of the bank. ESTIMATING GOLD IN PLACERS 31 The gravel obtained from the cuts has considerable bulk and may be washed in the rocker or sluice, the gold recovered, cleaned and weighed and calculated to its bank value. If the bank were 30 feet high then the material cut would be 1.5 X 2 X 30 = 90 cu. ft.; and if the gold in this material returned 20.67 cents the bank value would be found by the proportion 90 : 27 :: 20.67 : 6.198 cents per cubic yard. A deposit of gravel tested by a sufficient number of cuts so as to obtain a fair average sample and value will closely approximate the true value of the deposit in the places sampled, but where no exposure exists the value of the deposit back from the face is to be determined. This is accomplished either by a series of drill-holes or by sinking shafts. In some cases shafts may be excavated from the surface and drifts branched each way from the shaft bottom or it may be possible where the pay streak is near bed rock to drift in from the side or along the bed rock. To dig a shaft where from two to four feet of water is flowing near bed rock and obtain samples that will approximate true conditions is practically a physical impossibility; or if wet running ground is met in sinking a shaft the expense will become so great that some other method must be adopted, such as driving a casing pipe from the surface to bed rock. The results obtained at times from shaft tests have frequently been very close to those obtained under subsequent working conditions, but it is believed that they are more useful in shallow ground where there are no watercourses to interfere with their excavation or the recovery of test ground. 32 GEOLOGY OF PLACER DEPOSITS Shafts have the following points in their favor: (i) They furnish a large sample which may give more accurate returns than drill-holes. (2) The size of the excavation offers an opportunity to thoroughly inspect the ground at all depths, and if de- sired fresh samples can be taken as check samples at any time. Shafts are generally more expensive than drill holes, particularly those over 20 feet in depth, conse- quently their number is limited and this prevents a thorough test of the entire area. Some engineers believe that a few shafts should be sunk even when boreholes are used for testing the majority of the ground because they will check the boreholes and furnish data on the kind of ground to be worked later. In the past there has been considerable controversy as to the relative merits of shafts and drill-holes when testing placers, but after all the drills have made steady advances and are adopted now almost universal when testing new placer ground and also in testing where old placers are being worked. When testing by means of shafts two methods of obtaining samples are available: one where all the material excavated is washed, and the other where cuts are made down the sides of the shaft and the material so recovered is washed. In the first case the shaft may be made any size but some prefer to make it 2 feet 3 inches wide by 4 feet long, the object being to obtain one cubic yard of dirt every three feet in depth. If the shaft is circular it may be made 3 feet 5 inches diameter and the same amount of ground excavated every three feet in depth. Sinking shafts of such small size is slow as the men can- SHAFT TESTING 33 not work to advantage, especially where timbering is needed to prevent the walls caving, and it is for this latter reason that the rectangular shaft is preferred to the round shaft. The round shaft is the better of the two forms when the ground will stand because it can be dug quicker and kept in alignment better. For this latter purpose a template of two wooden cross pieces, about four inches less in diameter than the shaft is hung in the center at the top and lowered as sinking progresses. This prevents gouging the sides of the shafts which is a very important matter where rich streaks are encoun- tered. When either kind of shaft reaches bed rock that must be cleaned thoroughly even if it be necessary to sink a foot or two into bed rock, a condition which occurs only when soft decomposed rock is encountered. The material broken as sinking progresses is hoisted from the shaft in buckets usually raised and lowered by a hand windlass. If samples are from cuts in the sides of the shaft their cut widths should be uniform. One cut is taken from each end and one from each side. Where water is avail- able it is believed that more satisfactory results would be obtained from washing the entire quantity of dirt excavated, because of the larger sample. The difficulties encountered in testing wet ground when prospecting gravel deposits led to the introduction of the well drill. The cost of this method of testing being quite high and about that of some shafts created a de- mand for some other kind of drilling arrangement that would economize in cost particularly where the ground to be tested was not very thick. This resulted in the 34 GEOLOGY OF PLACER DEPOSITS introduction of the Empire Drill outfit, which is worked by hand augmented in some places by horse-power. The drill method of testing placer ground consists in forcing a pipe called a casing through the deposit to bed rock. As the casing descends the gravel in the interior is broken by a churn drill and the small particles made into a sludge of a consistency that will permit of their being removed by a pump. The sludge is washed to recover the gold. If the power drill is used the casing may be 6 inches in diameter, but where the hand drill is used it is seldoni over four inches. The area of gravel enclosed in casing pipes of this diameter is very small in comparison with an acre of ground : for instance No. 4 inserted joint casing would en- close an area of .0985 square foot; the No. 5 casing (6 in.) an area of . 196 square foot. Because of the ground under the cutting shoe of the casing being forced into the hole (that direction offering the least resistance), the area of the hole is increased by the thickness of pipe walls or to the outside diameter of the casing. The No. 4 casing has an outside diameter of 4.25 inches, the No. 5! casing an external diameter of 6 inches, therefore the ratio of these pipes in area to the acre would be about .0000025 part of an acre for the first pipe and .000005 P ar t f an acre f r the second. Another consideration to be mentioned in connection with drill-holes is that the pump used to clean the holes sucks material from under the end of the pipe and values taken for the exact diameter of the pipe are considered high. This was proved by W. H. Badford who sunk a shaft 3.5 feet in diameter at Oroville, California, us- DRILL-HOLE TESTING 35 ing a drill-hole in the center of the shaft to a depth of 34 feet. The gold obtained from the shaft corresponded almost exactly to the gold obtained from the drill-hole when using a factor for the latter of .27. This factor is im- portant, but should be modified to the diameter of the casing pipe. The outside diameter of an outside coupled pipe is 7.5 inches and it was with this kind of pipe that the test was made. As the area increases as the squares of the diameters the factor for any pipe can be readily found by the pro- portion, a 2 : b 2 :: .27 : x. If the gravel in an acre has the gold distributed uniformly throughout, the hole would afford an accurate sample of the deposit; such conditions, however, rarely exist and it is possible that a blank might be had close to rich ground, or the hole furnish the only piece of gold in the tract. It is evident from this reasoning that placer ground in new districts should be drilled to find both its probable area and its richness and while one hole per acre might do in old river beds one hole every 200 feet is about the area to cover in unknown territory. The reliability of a report on any placer deposit must depend on the care with which the examination was con- ducted, consequently when a large amount of capital is involved, great risk is assumed in deciding to make the expenditure on the result^of one drill to an acre. To be sure one Klondike estimate was based on a 1 6-foot shaft and a 6-foot drift for 1000 X 5oo-foot placer, and some engineers have based results making use of one drill-hole to the acre; it is believed, however, that more than a few GEOLOGY OF PLACER DEPOSITS of the many failures in hydraulic mining have been due to insufficient prospecting. In an article on "Valuing Dredging Ground" by L. A. Docoto 1 at least ten engineers took exception to the method which he advanced for estimating the average value of the ground. Because of the practical and theoretical points de- duced in the discussion Mr. Docoto's example is used to No. 3 No. 2 No.l 20ft. 50 c. '30 ft. No 0( 25 c. 30ft. No 11< 12 c. 25ft. 35 e. 20ft. No 7l 160 c. 25ft. No* r>< 10 c. 25ft. No 17< 12 c. 30ft. 40 c. 20 ft. 20 c. 35ft. Xn I'll 10 c. 32ft. 130 c. 20ft. No,-6< 50 c. 25ft. No-l-l-i 8c. 30ft. N0r-16< 10 c. 40ft. 30ft. 35ft. 30ft. FIG. explain the relation existing between the actual recovery of gold from a small area and the whole area and in cal- culating their values making use of the gold obtained from the boreholes. The plan, Fig. 5, is a theoretical map covered by 18 drill holes numbered consecutively. The value of gold from each hole is marked on the map in cents per cubic yard, and below it is marked the depth of the hole in feet to bed rock. To average the gold per 1 M. & S. Press, May, 1914. DOCOTO'S VALUATION EXAMPLE 37 cubic yard of gravel Mr. Docoto suggests that " the gold value from each hole be multiplied by the depth of the hole, that the products be totaled, and that this sum be divided by the total depths of the holes." The average gold value deduced by this method of estimation would, unless a safety factor were adopted to cover any probable loss, be reported as 37.69 cents per cubic yard. During certain periods of operation there will be a recovery above the average reported, while for other periods there may be less than the average. These special periods are neither times for rejoicing nor gloom since they are following out the sequence of events resulting from the ground being richer in one place than in another. To illustrate the recovery from a small area to that of the average gold value of the entire plot, let the lines join- ing the holes numbered i, 3, 8 and 6 enclose an area called A ; then the area bounded by the lines connecting holes 9, 10, 16 and 18 we will call B. If the average gold of area A is calculated as suggested, it will amount to 72.42 cents per cubic yard, while the average gold of area B will figure as 12.72 cents per cubic yard. This shows that neither the average gold value of A nor B can be taken as the standard by which to judge the average gold value of the entire area reported as 37.69 for the entire placer. It also shows the fluctuations that occur when an attempt is made to average ground from a few holes far apart. In commenting on the method it is to be understood that the ground to be valued is limited by the lines connecting holes i, 3, 8 and 6, and holes 9, 10, 1 6 and 18, but the entire area is bounded by holes i, 3, 18, 16 and i. 38 GEOLOGY OF PLACER DEPOSITS MR. DOCOTO'S METHOD OF CALCULATING Area A Area B 1. 130 X 40 5200 9. 25 X 25 625 2. 35 X 30 !5o 10. 20 X 25 500 3. 60 X 20 1200 ii. 8 X 35 280 4. 50 X 20 TOGO 12. 10 X 35 350 5. 40 X 20 800 13. 15 X 30 45 6 - 5 X 30 1500 14. 12 X 25 300 7. 160 X 20 3200 15. 10 X 30 300 8. 42 X 3 J 26o 16. 10 X 30 300 17. 12 X 3 2 384 210 15,210 18. 9 X 25 225 292 3714 Dividing 15, 210 by 210 gives an average value of 72.42 cents per cubic yard for Area A. Dividing 3714 by 292 gives an average value of 12.72 cents per cubic yard for Area B. Considering the area as a whole, 18,924 divided by 502 gives 37.69 as the average value in cents per cubic yard of gravel. Since the ground to be averaged is limited by the boundary lines connecting the holes 1,3, 18, 16 and i, the area of the corner holes are not representative of a square as Mr. Docoto's example would imply, but are one-quarter representative of an interior hole, say 5 or 7 ; further holes, 2, 8, 13, 12, 6 and n are only representa- tive of one-half of the area of 5 and 7. It will be evident from this that Mr. Docoto's average is too high although his average would be correct for the area given by the dotted lines in Fig. 6. The method to be followed in estimating the average value of placer ground is based on the fundamental principle which underlies the averaging of samples, namely: "A sample is supposed to represent the value DIXON'S METHOD OF VALUATION 39 of the ore, half way between it and the next sample ; with terminal samples, ore only on one side is taken into the calculations." l According to this rule the results of Mr. Docoto's tal- culations are not weighted proportionally to the volume " No. 3 COc. . r ~ n |No.8 42 c. | m No.l3,15c. No.18 1 9c. 25ft. 20ft. 30ft. 30ft. No. 4. 50c< | |NO. 9- 25c - . No.14^ 2 c - 25ft. ._. No. 2 35c. 30ft. INO. ? * 20 ft. No,12^ c * 35ft. No.17 12 c. 32ft. - *-SSJ *- No.l5. 10c - 30ft. - No. 1 L 130 c. 50 c. 8c. 10 c. 30ft. J 40ft. No. 630ft. i ; i i No.ll' 35 ft. No.16 FIG. 6. of ground they represent. The following method for calculation of this plot is advanced by James T. Dixon and is based on the rules given; at the same time it gives correctly the average value and depth of that portion of the area within the full lines of Fig. 6. The dotted lines Mine Sampling and Valuing, Herzig, p. 93. 40 GEOLOGY OF PLACER DEPOSITS represent the ground prospected, a value and depth being given in the center of each dotted rectangle. The average value is the total value divided by the cubical contents of the ground in question, and in order to arrive at the latter assume that the distance between the lines of holes is 2 #, and that between the holes 2 b. By this assumption fractions will be avoided. Referring now to hole No. i the area to be included in the calculation is a X &, the volume 40 b and the value contained therein is 5200 ab. By similar calculations the following results are obtained: MR. J. T. DIXON'S METHOD OF CALCULATING I. a X b X 40 X 130 = 5,200 ab 2. a X 2b X 30 X 35 = 2,100 ab 3- a X b X 20 X 60 = 1,200 ab 4. 2 a X 2b X 20 X 5 = 4,000 ab 5- 2d X 2b X 20 X 40 = 3,200 ab 6. 2 a X b X 30 X 5 m 3,000 ab 7- 2 a X 2b X 20 X 1 60 B 1 2, 80006 8. 2d X b X 30 X 42 = 2,52006 9- 2 a X 2b X 25 X 25 = 2,500 ab 10. 2 a X 2b X 25 X 20 = 2,000 ab ii. 2 a X b X 35 X 8 St 560 ab 12. 2 a X 2b X 35 X 10 = 1,40006 13- 2 a X b X 30 X 15 = 900 ab 14. 2 a X 2b X 25 X 12 1,200 ab 15- 2 a X 2b X 30 X 10 = 1,200 ab 16. a X b X 30 X 10 a 300 ab 17- a X 2b X 32 X 12 = 768 ab 18. a X b X 25 X 9 22506 Total m 45,07306 The gold in the calculated volume is represented by 45,073 ab and this divided by 48 ab, the area of the ground in question, gives 939.02 as the product of the average value and depth. To find the average depth let the line A, Fig. 6, graphically represent the depth in Fig. 7, which DIXON'S METHOD OF VALUATION 4 1 . also gives the boreholes and the distances between them. The area of this figure is 2 b (40 + 30) 2b (30 + 20) = 1 20 0. 2 2 Because the base has a total length of 4 b, the average depth is 1 20 b divided by 46 or 30. By similar calcula- 40 30 FIG. 7. tions the average depth of each line is found: Thus line A = 30; line B = 20; lineC = 25; line D = 25; line E = 33.75; line F = 27.5 and line G = 29.75. FIG. 8. These results may be graphically represented as in Fig. 8. Since this line is at right angles to the previous ones, the distance between lines, namely 2 a, is shown 42 GEOLOGY OF PLACER DEPOSITS and proceeding as before the total area is found to be 322.25 which divided by 12 a gives 26.854 as the average depth. Previously the product of the average depth and average value was found to be 939.02 and this divided by 26.854, the average depth, gives 34.96 cents as the average value per cubic yard. No units are designated in this calculation as they make no difference provided that the same units are used throughout. The Dixon method is applicable to all cases whether the lines or boreholes are spaced evenly or unevenly. For practice the reader may calculate the averages by taking the lines of boreholes horizontally or diagonally instead of vertically as in this calculation. The results will be found the same, which shows that the method is correct. One feature brought out by Mr. Docoto's theoretical problem was the noticeable fact that eight men had different ideas regarding the correct method to be used in arriving at the average values of the plotted area, and consequently obtained different results, some of them varying as much as 8 cents per cubic yard. Another feature previously mentioned was that the use of pris- moidal formulae failed to furnish the correct answer. Before entering on the subject of drills the method of testing " bench deposits" is described. In testing placer deposits by drifts, whether they are advanced from the outside or from the bottom of shafts, it is advisable to wash the entire bulk of the ground broken in the drift. If the deposit is deep and wide the costs of prospecting by shafts at intervals is expensive and not more reliable TESTING BENCH DEPOSITS 43 than to drive headings each way from the bottom of a shaft towards rim-rocks. It is advisable to drive the headings on bed rock, in a direction that will be at right angles to the flow, to reach the rim-rocks by the shortest distance, also to obtain more accurate values than would be the case where the excavations were made at an angle more or less parallel to the channel. In driving drifts of this kind it is neces- sary that the ribs or side walls of the excavation be kept straight and of uniform width, as gouging would probably increase the values from the pay streaks and decrease them if barren ground is gouged. In drifts of this kind it is customary to base the value of gold obtained on the number of square yards of bed rock uncovered, then from this datum and the thickness of the gravel above bed rock along the line of the drift the value per cubic yard is computed. As an illustration: Assume that the deposit increases in depth uniformly from rim-rocks to the center of the channel, and that all the gold is deposited in a stratum or bench on bed rock, having from 18 to 24 inches thickness. To test this deposit assume a shaft is sunk 39 feet to bed rock and that by drifting at right angles to the channel the width of the deposit was found to be 72 feet. The area of the excavation was made 5X6 feet for convenience in working, and the width was kept uniformly 5 feet, until the ribs reached the height of 4 feet 9 inches when the roof was arched, or if weak was supported by timber sets, and lagging. When driving, all dirt was wheeled in barrows to the bottom of the shaft and hoisted to the surface, where it was washed in sluice boxes, the gold being caught in 44 GEOLOGY OF PLACER DEPOSITS riffles. By drifting $181.38 in gold was obtained from 72X 5-5-9 = 40 square yards of bed rock uncovered; thus the yield was $4.53 per square yard. By surveying along the line of the drift the average depth of the cover was found to be 33.3 feet or n.i yards. Dividing the value per square yard of bed rock by this depth in yards the value of the assumed deposit is found to be 40.8 cents per cubic yard. FIG. 9. Prospecting with Drills. It is now generally con- ceded that placer prospecting may be accomplished with great saving in time and fairly accurately by the use of percussion drills. The Keystone Drill rig shown in PROSPECTING WITH DRILLS 45 Fig. 9 is a portable well drilling rig that has found favor in many countries. With this power drill the earth in the bottom of the hole is broken in advance of the casing pipe which follows. As soon as the casing reaches the bottom of the hole, water is poured in and a sludge formed of such consistency that it may be drawn out by a pump. It may be necessary to have water in the bottom of the hole at all times, especially when drilling rock; then again water may naturally be present; however, before the pump is used the casing should be at the same depth as the bottom of the hole, otherwise it may be enlarged by the action of the pump. The muck raised from the hole is poured from the pump directly into a washer and the gold recovered. In recent years the Empire Drill has found favor among engineers. It consists of a combination of ar- rangements obtained by assembling the ancient post-hole augur with the churn drill, and such other advantages as well drills possessed; at the same time there is original invention displayed which places it in a class by itself. The outfit consists of a pipe or casing supplied at one end with a sharp-toothed cutting shoe, which is kept loose in the hole by rotation and in this way sinks evenly with the bit of the drill. To this pipe, at suitable distance above the ground, an iron platform is fastened as shown in Fig. 10. On this platform men stand to raise and lower a drill which is inside the pipe. The drill consists of a series of rods having a bit at the lower end with a grip handle at the upper end for the purpose of raising the rods and letting them drop about i foot. 46 GEOLOGY OF PLACER DEPOSITS In all percussive drilling water is required for making sludge at the bottom of the hole in order that the ma- terials may be removed and permit the drill to cut the rock. The sludge pump is a working barrel with a flap valve in the bottom which opens inwards as it descends and downwards as it ascends. Sometimes this pump works slowly and so fails to clean the hole as much as desired, therefore the vacuum sludge pump is finding favor. This consists of a working barrel as before with a foot valve, but in addition it has a piston valve on a rod which on being moved upwards causes a vacuum and draws the sludge into the barrel. The method of work- ing the drill is as follows: PROSPECTING WITH DRILLS 47 The casing is started by boring a hole with a post augur to a depth that will insure the former remaining vertical. After insertion in this hole the casing is rotated by a sweep pushed by men or animals, thus cutting a core in the ground from the surface to bed rock. To sink the casing and afford grip to its cutting bit, there is the com- bined weight of the platform, the drillers, the drill rods and the casing. This combined weight is always suffi- cient to sink the casing when rotated and kept loose in the hole. Although a core is marked out by the casing, nevertheless most of the drilling is done by the tools inside the casing being churned up and down by the drillers. One of the recent improvements to the Empire rig is the use of a hollow drill stem attached to the bottom of a sand pump which in turn is fastened to the drill rods. This combination picks up the drill clippings as fast as cut, provided sufficient water is kept in the hole to form a fluid sludge. The advantages claimed for this com- bination are: the casing is sunk and the material re- moved out of the way of the bit at the same time, thus doing away with three operations which other drills require to accomplish the same advance; viz., raising and uncoupling the drill rods every time the hole has to be cleaned out, using the pump, lowering the drill rods after sludging. When boulders or other obstacles are en- countered which interfere with sinking, a heavy fluted rock drill is attached to the rods and the sand pump mentioned is removed from the sinking rods and a solid string of tools thus obtained. The combined action of the casing and drill are such that the obstacle is readily 48 GEOLOGY OF PLACER DEPOSITS passed through, although it may be possible to shatter the rock in the bottom of the hole with dynamite and thus hasten the process. When a hole is completed to bed- rock, the casing is pulled by suitable tools and reused for putting down another hole. The weight of the ap- paratus without casing is 1000 pounds; however, as no one piece weighs more than 75 pounds, it is considered port- able. The weight of the complete outfit with 4-inch\ casing and necessary drill rods to drill to a depth of 25 feet is 2000 pounds; to drill to a depth of 50 feet, 2500 pounds. For greater depths the weight of the outfit increases at the rate of 20 pounds to the foot; thus to drill to a depth of 100 feet the weight would be 75 X 20 + 2000 = 3500 pounds. J. P. Hutchins and N. C. S tines furnished cost data based on their work with this drill rig. The late Fritz Circle who made use of it in Canada recommended the drill and his account will be found in one of the Canadian Bureau of Mines Reports. " With labor at $i per day and a horse at $i per day, with ground from 30 to 50 feet deep, the actual drilling costs from 12 to 30 cents per foot. In frozen ground 25 feet deep in which 2 feet per hour may be averaged the cost is 23 cents per foot. In Idaho, with labor at $3.50 per shift and working under the disadvantages of deep snow and very cold weather, 37! feet were drilled in 8^ hours at a cost of 65 cents per foot. Under more favor- able conditions in Colorado, with labor at $2.50 per day, the progress was 42 feet per day and the cost 27 cents per foot. Where labor was 20 cents per hour and the gravel 18 feet thick five men and one horse averaged 51 PROSPECTING WITH DRILLS 49 feet per day at a cost of 23 cents per foot." Among the advantages to be considered when making use of this outfit is its portability; thus the holes for the casing may be started in advance of actual drilling, or on account of its light weight several drills may be worked over the ground to be tested at the same time. In comparison with the steam power drill the cost of the outfit is less and it can be used where the steam drill would be impossible. Where holes are to be more than 25 feet deep it is possible to effect a saving in operating costs by adopting the Empire spring drilling attachment. The action of this apparatus is similar to the spring pole and has the added advantage of assisting in raising and lowering the drill rods when they must be drawn from the hole. The attachment consists of a small drum geared to a crank and shaft. There is a brake attachment to the drum which enables the operator to drop the tools at will. The spring is also attached to the drum shaft, and when given tension sufficient to counterbalance a string of tools, it aids the drillers greatly in raising them just be- fore letting them drop. This is accomplished by attach- ing a rope to the drum, and to the string of tools at some distance below the surface in the hole. With this at- tachment two men have drilled to a depth of 125 feet. CHAPTER II. HYDRAULIC MINING. HYDRAULIC MINING was once defined as a method of mining in which water broke down gold-bearing earth, transported it to sluices, and separated the gold from the earth. The definition is not sufficiently broad, as hydraulic mining when applied to gold-bearing earths not only breaks and transports, but washes the material and per- mits the gold to separate by its greater specific gravity. It is also a concentrating and sluicing process. The process of mining and transporting by water can be applied to coal, iron ore, salt and possibly other minerals, for which reason, the term hydraulic mining should not be confined to gold alone. In view of the scope that the term covers, the suggestive term " hydraulick- ing" is applied to gold mining, and the term hydraulic mining used to cover all materials mined by the use of water. Hydraulic mining frequently requires the services of civil, hydraulic, mechanical and mining engineers to install a plant, or at least an engineer who is able to combine those branches of the professions mentioned that enter into the business. Before any attempt is made at engineering the gold- bearing ground should be prospected carefully, in order to ascertain its extent and value. Several million 50 ANCIENT MINING 51 dollars have been expended in overcoming difficult engineering problems to wash dirt that did not contain sufficient gold to pay the cost of the plant, which fact emphasizes the need of thorough prospecting. The value of the property having been determined, it may be necessary in order to work it successfully to construct dams for storage reservoirs, and a combina- tion of flumes, ditches, and pipe lines, extending from one to one hundred miles in length, and in addition it may be necessary to tunnel mountains, span chasms, siphon across valleys, place flumes on high trestles or suspension bridges, and possibly bracket them to the sides of high cliffs. From what has been stated the reader will understand that hydraulic mining may in one case be simple while in another it may be intricate and difficult. It is only possible to describe many matters entering into the subject in a general way, while the most impor- tant are described in detail. The use of water for mining dates back to King Solomon's time. Agricola informs us that fire was used to heat the rocks, and then cold water was thrown on them to spall them. 1 In quarrying where seams exist in bedded rock, and where explosives would be apt to shatter the rock being quarried, water is employed with wood. 1 While recently in Cuba, the author heard that Cubans used to mine an ore, bum it and then wash it in pans. Upon investigation a calcite vein containing gold was found, and since the Cubans had no machinery this method answered their purpose. A little of the ore was treated this way and gave good results, showing that the ancients were not so slow where gold was concerned. 52 HYDRAULIC MINING The method followed is to drill a series of holes back from but parallel to the face, on the line of cleavage. Into these holes dry wooden wedges are driven. These wedges, on being wet, expand and split the rock as desired. The plug and feather generally in use in such cases does not always answer as well as the wedges mentioned. The danger which arises from the use of gunpowder in gaseous coal mines has produced two classes of expansive cartridges which depend upon water for their utility. The coal is undercut in the usual manner, and holes drilled in the section to be broken down. 1. Into these drill-holes cartridges of compressed quicklime are inserted, after which they are moistened, then tamped. The water used to moisten the lime causes it to slack, expand, and generate steam; this combination breaks down the coal. The economical value of this novelty has not been fully established in this country. The number of drill-holes and lime cartridges would possibly bring the cost of the process up to that of powder; however, the smaller undercut, and the reduction in the amount of slack coal produced, compared with powder, may counterbalance previous objections. The distinctive advantage which this process possesses is the avoidance of explosion in mines which are subject to outbursts of gas. 2. The water cartridge of the second type is also intended for use in fiery coal mines. It is a metal wedge, so contrived that upon the appli- cation of hydraulic pressure it will expand. To break down the coal a series of wedges are con- SALT MINING 53 nected, so that when the pressure is applied it is uniform on all. The cartridges being indestructible may be used over again. They have not come into general use in this country. Cartridges of this description, if they could be used from water pressure at the mouth of some metal mines in the West, would be a great bless- ing, in preventing the fouling of air and loss of life, not to mention economy in the matter of powder, time, and fuse. Their use would be limited to overstepping. Salt mining uses water in practical ways as follows: i. As a solvent. For this purpose a series of bore- holes are drilled from the surface down into the deposit by percussion or diamond drills. Water is then run into the holes and allowed to become saturated with salt, after which the brine is pumped out and more fresh water added. By a series of these bore-holes near together an under- ground water course which connects the holes is soon formed in the salt bed. Nitroglycerine fired in the holes will shatter the rock and is useful in hastening the connection. The water, after circulation is estab- lished, flows continuously from the surface into one hole, and is pumped out at the same rate it enters from an- other hole. The working is now permanent, one bore- hole supplies the water, and another is fitted with a deep well-pump to remove the brine. This method has advantages, in some instances, over any other method of mining salt where the material is to be broken down, hoisted, dissolved, and then con- centrated. It also offers the further advantage of leav- ing the impurities in the mine, and brings the article 54 HYDRAULIC MINING sought in the proper concentrated form for refining to the vats. 2. The hydraulic mining termed " spatterwork " origi- nated in the salt mines of Europe, where it has received considerable attention. The water used for mining is given a gravity pressure and ejected from a nozzle having a number of small orifices. The water from this nozzle strikes against the salt deposit and wears it away; at the same time, in flowing away it dissolves the salt, leaving the worthless debris to be broken down or removed. The brine is then collected by gravity in sumps or sub- terranean reservoirs, from which it is pumped to the surface and evaporated. Spatterwork can be employed in salt deposits for sinking shafts and winzes -from a higher to a lower level, or making "rises" from a lower to a higher level. FIG. ii. Gangways or rooms may be driven in salt deposits by the method crudely shown in Fig. n. For side cutting, the main supply pipe for water has coupled to it, by a hose, a standpipe, SP. This pipe is wedged between the roof and floor, in an upright position, with the ori- fices directed toward the face. The water jets wear SPATTERWORK 55 away the deposit by solution and abrasion, and the deposit recedes from the orifices of the water jets until the projective force of the water has reached its limit. The water is then turned off and the column pipe placed in another position, where the water by its pro- jective force, together with its solving action, can per- form more effective work. The same illustration shows the method of under- cutting the deposit of saliferous clay. The spatter pipe is placed upon the floor and is moved forward to deepen the excavation, or laterally to widen it. The undercut having been made, the clay is easily wedged down SP FIG. 12. FIG. 13. where it may be acted upon by a stream of water which takes the salt into solution and leaves the barren dirt. The quantity of water is limited to the capacity of the pumps and that necessary for saturation of the brine. Water may, in some instances, be used on one level and be permitted to flow to the next lower level, and 56 HYDRAULIC MINING so on, thus attaining the requisite saturation before reaching the pumps and sumps. Wherever the latter conditions prevail, winzes or risers may be made as roughly sketched in Figs. 12 and 13. To sink the winze, it is necessary to drill a bore-hole from the level above to the level below, to allow the escape of the water discharged from the nozzle N. The water from the supply pipe on the upper level acts by gravity, and propels the water from the jet holes in the nozzle against the sides of the shaft. It is evident in this instance that the action of the water increases its projective force with depth until it reaches its maximum when the lower level is reached. Fig. 13 shows the method of working out a "rise." To facilitate this latter method, water is brought under pressure greater than the height to be driven, as it decreases in projective force with height. Mr. Oswald J. Heinrich stated that with a 21 -foot head of water, and side cutting from a spatter pipe having twelve brass orifices \ mm. diameter, the advance was 0.6 square feet per minute, with i cubic foot of water per minute. One man attends to 12 spatter pipes in a 1 2-hour shift. This rate of exca- vation is in round numbers 5184 cubic feet per day, with 8640 cubic feet of water and one man's labor, thus comparing favorably with any hydraulic mining, as it is .052 cents per cubic yard for labor, and not as high in amount for water as gravel mining generally. Iron ore deposits of an alluvial character, such as are the " brown ore" deposits of Virginia, can be worked to great advantage by " hydraulicking " if situated on IRON ORE MINING 57 side hills. In such instances the ore is disseminated through clay with barren rocks in such a manner as to need both concentration and washing. It may be ne- cessary to wash ten tons of material to concentrate one ton of ore. The cost of excavating and handling such lean iron oxide deposits would make the bed commer- cially unprofitable, if freight must be added ; it has, how- ever, been practically demonstrated to be more econo- mical to burn fuel and pump water uphill and hydraulic than to work by the former method. To illustrate this more fully : to pick, shovel, and transport the material to the washer, wash it, and load it on cars, will cost, for 10 tons, $2.00 i.e., one ton of iron ore. To accomplish the same work with water having a head of 50 feet will cost 75 cents per ton of iron ore. The hydraulic system materially lessens the work to be done by the washer, as the ore becomes freed in a measure from clay as it travels through the sluices to the washer. There is one more system of water mining made men- tion of by Pliny in his "Natural History." It has been practiced somewhat in this country, and is termed "booming." The process of "booming" is to make a dam and collect water; whenever the dam is full the gates are opened quickly, allowing a torrent of water to rush down the hill and upset matters generally. The water, having done its work, is led through sluices which are nearly on a level at the foot of the hill; in these sluices the gold washed out of the soil is collected. Booming has some advantages which are not to be 58 HYDRAULIC MINING overlooked. If there is little water and little working capital the method will be found very serviceable, or if there is considerable water and little working capital it again appeals to the miner. In some cases where there is abundance of capital the method is adopted as the one most feasible for placer mining. Booming will wash out a large quantity of material, and in its operation is an imitation of a cloud-burst rushing down a ravine. Where there is top dirt above a placer, booming affords a quick and easy method of removing it, provided the dirt is not hardpan and cemented gravel. Float gold and leaf gold cannot be saved if booming is practiced, and only partially saved by other hydraulic methods. In Colorado at the Alma and Fairplay placers a sys- tem of hydraulic mining termed " ditch waterfall" and " flume waterfall" mining is practiced. At these places there is plenty of water, and this flowing through ditches wears away the earth. The water in the ditch naturally cuts its own channel, thus forming narrow ravines and gashes in the deposit that are useful in assisting the water spurted from nozzles in tearing down the bank. By shifting these ditches or by turning the water into other ditches, considerable space may be covered and the earth washed down to the sluice boxes without any cost of attendance. This method combined with the pipe work practiced at these places forms the most satisfactory system of hydraulicking. Unfortunately, however, it cannot be followed at every placer mine. CULM PILE MINING 59 In the early days of anthracite mining, great difficulty was experienced in the preparation of coal for market. All bone coal, or coal frozen to slate or rock, was thrown on the rock pile; and in addition all coal smaller than chestnut size, that passes over a screen with f-inch mesh, but through a screen having a mesh if inches square, was discarded. This waste accumulated so FIG. 14. fast that the culm piles throughout the three anthracite felds became veritable mountains. With the increased demand for coal, the attention of coal operators was given to preparing smaller sizes than chestnut for steam purposes. In 1867 pea coal was first utilized for fuel; in 1878 buckwheat was shipped on a small scale, but as soon as McClave's rocking grate and the Wooton or camelback locomotive were introduced the demand increased rapidly, until at the present time 60 HYDRAULIC MINING No. 3 buckwheat or barley size is prepared and shipped in large quantities. When the demand for small sizes became greater than the mines could produce, attention was turned to the utilization of the culm piles. These are mined by water; in fact, hydraulic mining is now carried on to a larger extent for mining coal in north- eastern Pennsylvania than for mining all the other minerals in the United States. The stream of water from a nozzle washes down the coal into a sheet iron trough placed at a slight inclination. The trough con- nects with the washery where the coal is prepared for market, or with a swinging scraper line such as that shown in Fig. 14 leading to the washery. 1 Dredging for coal in the Susquehanna River is also carried on from Wilkes Barre to Sunbury, Pennsylvania. The coal found in the river has been transported from the waste dumps at the collieries and from the washeries adjacent in the river. 1 M. and M., 1903, June. A. I. M. E., Nov., 1905. George Harris. CHAPTER III. DEVELOPMENT OF PLACER MINING. IN the early days the ancients depended on placers for their supply of gold. As they had practically no machinery suitable for quartz mining, it may be assumed that the Egyptians previous to Herod's time practiced some form of hydraulic mining. The Romans sluiced for gold, and according to Pliny the shores of Spain were added to by booming. One English writer states that nine-tenths of all the gold has been recovered by hydraulic methods, while an American writer declares that over seventy- five per cent of all the gold mined has been derived from working gravel beds. Probably five- tenths of all the gold recovered at a profit has been taken from placers. While placers are not as rich ordinarily as veins, and while they cover vastly greater areas than vein formations, nevertheless the gold is more easily recovered from them. This is due to Nature's pulverizing the rocks and concentrating the gold, thereby doing away with underground mining, crushing, milling, or smelting, items which add so materially to the cost of production that vein mining frequently pays only expenses, and more frequently shows a debit balance on the ledger. The pan, cradle, and sluice were first introduced in the Southern States before gold was discovered in Cali- 61 62 DEVELOPMENT OF PLACER MINING fornia, but hydraulicking as now practiced was devel- oped in California. Panning. The ordinary gold pan of the prospector, while very useful is an imperfect appliance in which to save fine gold. While colors of gold may be de- tected by the pan, it is very difficult to collect them free from black sand, consequently the pan is useful to placer miners only for nugget gold, unless they use mercury, and this they seldom do. In tracing up gold deposits the pan has no equal, particularly deposits that show free gold. The Spaniards introduced the batea or wooden pan into Mexico, where they are still found to some extent, when sheet iron pans are not available. The most expert panner the writer has ever seen was a Mexican Indian who used a small lo-inch frying-pan with the handle knocked off. The ordinary sheet iron gold pan, from 16 to 18 inches in diameter, will hold from 15 to 25 pounds of dirt, and with its load will require the use of both hands during washing operations. A smaller pan 10 inches across the top will hold from 3 to 5 pounds of dirt and can be manipulated with comparative ease, and is, therefore, better for prospecting. A good placer miner, by washing continuously ten hours, can pan from one-half a cubic yard to one cubic yard of dirt, depending of course on the character of the dirt and his nearness to water. If the ground is loose and contains stones of the size of one's fist, more can be washed than when the ground is fine or is cemented material. Ordinary gravel, as found in placers, will probably average 135 pounds per cubic foot; at this GOLD PANNING 63 figure 27 cubic feet would weigh 3645 pounds. Assum- ing that each pan washed contained 15 pounds, then it would require 243 pans to wash a cubic yard. A good days work for a placer miner under medium conditions is 100 pans of dirt in 10 hours. It is difficult to describe the motion given to a gold pan when washing FIG. 15. dirt; the object, however, is to separate the gold from the material with which it is associated. The placer dirt is shoveled into the pan until it is heaping full. The pan and its contents are then submerged in water, to loosen the material. The large stones are washed first to remove any adhering dirt that may contain gold, after which they are thrown away. The contents of the pan are then kneaded with both hands, to break up 64 DEVELOPMENT OF PLACER MINING clay, and float the mud away. When there is nothing but sand and gravel in the pan, the panning operation commences and is continued until only the heavier particles remain. If a little clear water is now added the gold in the bottom of the pan will show. In most cases only the gold is saved; however, the black sands may be so valuable it will pay to save them, particularly if there is flour gold. Gold frozen to quartz is frequently found when pan- ning. This rock should be pulverized and treated as in pan assaying. The pan for this purpose should be black, of Russian sheet-iron, and of the shape shown in Fig. 16. The pan is held firmly by one hand, some water is then poured on the pulverized ore; the other hand is used now for shaking the pan in a gentle but rapid manner. The powdered ore being gathered to one FIG 16 s ^ 6j ^ e neav 7 g rams of gld de- scend through the sand to the bot- tom of the pan and settle. After shaking the pan a few minutes, it is to be moved so as to produce a gentle current in casting off the water. This will carry off some of the sand and diminish the quantity in the pan. Fresh water is now added, and another portion of sand washed away, this operation being repeated until nearly all the sand has been washed from the pan. A little water being retained in the pan, the concentrates are moved around by inclining the pan, and giving the water a rocking motion. The gentle current produced BATEA by the motion will float the sand away and leave the metal in view. Assaying by the pan is not accurate, as only the coarser particles are retained, the finer going off with the sand. At times it is customary to rock the pan back and forth with the last water slightly and then make a line with the material remaining by inclin- ing the pan to one side. The gold being the heavier, remains at the point of the line in what is termed a pen- cile. If a batea with a hole in the center has been used for the operation, the gold may be separated from the sand by pushing it through the hole, after it has been collected in the center by a rotary motion. The Mexican batea (Fig. 17) is a good tool for placer miners, but it does not possess advantages over the iron pan, except, perhaps, in the matter of collecting sulphurets in sample assaying. The wooden bowl IG ' I7 ' is given a steady circular shake without revolving, alter- nated with a reciprocating motion, which settles the heavier mineral in the center of the bowl ; on inclining it the sand flows to one side. In washing they are filled with the dirt the same as pans, immersed in water, and stirred by hand; a circular motion is given to the bowl, which is also slightly inclined, allowing the sand to wash over the sides. The gold sinks to the bottom and clings to the sides of the batea, which requires, generally, more care in manipulation. To work either the pan or batea requires care and experience; and some become very expert in their use. 66 DEVELOPMENT OF PLACER MINING The Rocker. To do away with tedious panning and to increase the quantity of dirt that could be washed in a given time some one invented the rocker. Rockers are designed in many forms, to suit the ideas of the individual, and often to suit the material to be washed. The contrivances are rocked back and forth; one swing, however, is longer than the other, the object being to settle the heavy material. In some cases the short swing is brought to an abrupt stop by a block, but more often the man manipulating the rocker decides on the length of swing from the fact that rocking like panning is not an entirely mechanical operation, but requires skill and judgment. The dimensions, like the construction, are varied to suit the ideas of the miner. A fair-sized rocker is about 6 feet long, 24 inches high, and 15 inches wide in the bottom, and 19 inches wide at the top (Fig. 18). The floor of the rocker is given a slant, with the feed end, B, about six inches higher than the discharge end, O. This inclination should depend upon the material to be washed and the amount of water available. Fine gold should be given less water and less inclination than coarse gold. Iron bars, parallel to the sides of the trough, are placed on edge, making a grating, known as a "grizzly." These bars AMALGAM 67 have end rests, and if too limber or given to buckling should be stiffened by intermediate rests. The spaces between the bars are from f to J inch. Perforated or slotted metal plates are more convenient and will answer the purpose as well as bars, besides are more economical if well braced across the rocker. A current of water is let in at the upper end of the rocker, on the ore; this water passes through the grating, carrying the finer material, sand and gold, with it into the box, C. If the gold is fine, quicksilver is placed in small quantities in the box, to form an alloy termed amalgam. The light sand in C is swept out by the current of water which passes through the grating at O. At each swing the coarser dirt which does not go through the bars is moved by the jar towards the discharge, O. The jar may not be sufficient to dispose of the coarse material, in which case the miner uses his shovel for that purpose. While rocking is quite effective for coarse gold, there is much fine float gold lost even when quicksilver is em- ployed. This is especially the case when much clay is present as that encases both coarse gold and fine, and since the specific gravity of the two combined is less than for gold alone, the density of muddy water may be sufficient to buoy the fine particles, which float away in the agitated current of water. Mercury cannot reach fine gold smeared with clay, and it may be worth while, therefore, to go slower and use more water to wash off the clay. Where there is much clay a good plan is to feed the material and water into a trough, and allow the dirt to be moved by the water along the trough and discharged 68 DEVELOPMENT OF PLACER MINING into the rocker. The clay will be washed more thor- oughly from the gold by this means, and the latter be given a better opportunity to form amalgam. Another form of rocker is shown in Fig. 19. This is a box with sloping sides, about 36 to 42 inches long and 1 6 inches wide, with a rocker near the middle and one near the back. There is a hopper, H 3 20 inches square, FIG. 19. 4 inches deep, whose iron bottom is perforated with |-inch-diameter holes. This hopper is removable. Under this hopper, on a light inclined frame, C, a canvas apron, A, is stretched, to form a riffle. The water is poured 'on the dirt, which is shoveled into the hopper, washes the .gold and sand through the screen, after which the coarse material in the hopper is thrown aside and new dirt substituted. The rocker has pieces of plank, Rj nailed transversely across the bottom, to catch the gold as the current transports the sand to the discharge end. The rocker shown in Fig. 20 is used in the South, and those natives who have the gold fever consider it the best apparatus for washing dirt in existence. Al- though it is a crude affair it is nevertheless effective in CRADLES 69 the hands of one accustomed to its manipulation. The Southern placer gold is fine, most of it being mere colors, so that pieces from the size of mustard seed up are called nuggets. Men cannot pan sufficient quantities of this dirt to make wages, but with a rocker can treat from 2 to 2j cubic yards daily. The rocker has two longitudinal riffles, a, placed about as in the cross-section. The riffles are about the thickness and width of bed slats, FIG. 20. North Carolina Trough Washer, the object being to retain the black sands and gold between the two. The dirt to be washed is shoveled into the tub until the bottom is covered. Water is next poured in and the apparatus rocked to clean the mud from the larger pieces of stone. The cradle is then tilted until the dirty water will run out of plug holes, b, after which the larger pieces of rock are raked out over the side. This operation is repeated until the water poured in and agitated remains comparatively clear, and there are but few small stones in the tub. Expert work now begins, the object being to wash the light sands over one riffle and leave the gold and heavy black sands between the two riffles. To accomplish this a quick jerk is given the rocker one way, and then as the water moves to one side it is allowed to come to rest slowly and flow back. The motion is similar to that 70 DEVELOPMENT OF PLACER MINING given a pan when a pencil of black sand is being formed, except that the height of the wave movement is decreased gradually on one side of the tub and increased on the other until all the light sands are on the long-wave side. When this is accomplished the heavy sands are between the riffles, and the gold is picked out. Expert manipu- lators of these cradles claim that they can save 90 per cent of the gold. They do not use mercury either in the cradle, or in the clean-up, from the fact that it costs money, becomes foul quickly, needs retorting, and must be cleaned before it will amalgamate properly, all of which means extra labor and expense, which they cannot stand, with such small operations. Combination rockers, such as were used at Gold Hill, North Carolina, are made by connecting several single rockers by rods, the pulp being conveyed to them by a trough. The riffles in these rockers are crosswise of the trough and only one end is closed, making it virtually a rocking sluice box. A woman often furnished the motive power, shifting her weight alternately from one side of one rocker to the other. In many instances these rockers were used as concentrators in conjunction with Chilean mills. The Long Tom is a short sluice box that is used in place of the rocker in suitable localities. It requires one man to feed it and another to keep it in working order. It is capable of washing 6 yards of ordinary dirt, and from 3 to 4 yards of cemented dirt in 10 hours. The material to be washed is shoveled into the sluice box, H, Fig. 21, and that being supplied with an abund- ance of flowing water, carries the dirt to the torn. The LONG TOM 71 feed end of the torn is about 18 inches wide, while the dis- charge end is about 32 inches wide, and terminates in a perforated sheet-iron plate, P. As the material enters at T, it spreads out until it meets the plate, P, where it is immediately riddled and so assorted, that all stuff finer than one-half inch in diameter falls with the water into a second trough, T, one end of which is underneath FIG. 21. the plate. The coarse material is shoveled off the plate, and the lumps of clay and dirt thrown up towards the head so that the water will have another chance to disintegrate them. In order to facilitate the movement of material in the troughs the latter are placed on timbers or stones to give them a slope towards the discharge. The lower box is furnished with transverse riffles, R, which collect the gold that moves with the stream of water. The constant movement of the water beneath the plate keeps the sand suspended and allows the gold to sepa- rate and sink by gravity to the floor of the trough. The inclination of the riffle box should be such that the bottom of the trough is covered with a thin coating of mud, and is not scoured by swiftly running water and sand. Mercury can be used in the riffles to assist in retaining the gold, and the riffle box can be supplemented with 72 DEVELOPMENT OF PLACER MINING another box containing blankets or hides with the hair turned up stream to catch the fine gold. In the latter case a fine screen with not larger than n inch mesh holes should be placed above the blanket, in order to prevent coarse sand and gravel from traveling over and wearing it. On Snake River, Idaho, very fine float gold has been saved by such means. Sluicing is a term used to indicate the process of washing dirt through a channel by means of water. The channel through which the dirt is transported may be a wooden trough, or a ditch cut in bed rock. The sluice is the most important part of any hydraulic min- ing system, and if it is not constructed properly there will be a loss of gold. The earth may be fed to the sluice by hand, or indirectly by machinery, or it may be washed from a bank by a stream of water that is after- wards led to the sluice. Fig. 22 shows a hand sluice into which the miners shovel the gold-bearing dirt, previously picking out the large stones and throwing them one side. Similar sluice boxes, although much larger and stronger, are used where mechanical apparatus is employed for excavating. The water in flowing through the sluice transports the material to the dumping ground, and at the same time washes the gold free from rocks to which it is adhering, and permits it to fall to the bottom of the sluice, where it is caught in artifical traps called riffles. There should be arrangements to prevent large stones entering a small sluice as they wear the boxes, require more water for their transportation, or else a heavier grade, than do smaller stones, and are otherwise objectionable. In 74 GROUND SLUICES 75 many cases all material to be washed passes through grizzlies that prevent stones larger than 3 inches in diameter from entering the sluice. In ground sluicing this is not always practicable, as the material is delivered so fast screens would become clogged, for which reason a man stands at the head of a sluice and pulls out the largest stones, and prevents the others from clogging the entrance. Ground sluices are bed-rock sluices, and must be constructed with great care, as much depends upon them. They are objec- tionable because they can be cleaned up only once in a season, and because all boulders have to be removed out of the way by derricks. The motive power for the der- ricks is obtained usually from water, and a Pelton water wheel. Upon the construction and operation of a sluice much of the success of placer mining depends. Steadiness of flow, that is, the quantity of water passing and its velocity should be uniform to secure a maximum settling of the gold. To be sure it is not always possible to prevent crowding a sluice, particularly when caving a bank, but there is no economy in doing so, and generally an experi- enced pipeman can avoid it. If the bank runs in too freely so as to send large quantities of dirt to the sluice, it may be economical to construct other sluices. The bulk of the gravel and boulders travel down the middle of a sluice, hence its grade and depth are important, yet the fact that a swift current while able to transport heavy material will not permit fine gold to settle must not be overlooked. The sectional area of a sluice will depend upon the 76 DEVELOPMENT OF PLACER MINING quantities of water and dirt it is to carry. An ordinary sluice will probably be made of 2-inch planks, 12 inches wide and 12 feet long. This sized lumber will furnish a box 12 inches wide by 10 inches high. The boxes are generally made in 1 2-foot lengths, and as many placed end to end as the nature of the ground demands. They should be caulked with cotton wick if oakum is not readily attainable, to prevent leakage, and if they are to carry fair-sized stones should have false bottoms, which may be made to act as riffle bars. The sluice boxes should be placed in a straight line, but if curving is necessary, the outer edge of the curve should have an elevation, to prevent the material from piling up and clogging the box when the direction of the flow is changed. There should be at least one inch elevation for each degree of curvature, but even this will not in all instances prevent retardation after the curves have been passed, making it necessary to give a slightly greater fall below the curve in order to obtain uniform flow of material and clear the curves. The grade necessary to give a sluice will depend upon the character of the alluvions; large, heavy stuff will require a steeper incline than lighter material. The amount of water at command will influence, in a meas- ure, the gradient, and the sectional area of the sluice must also depend upon it. Heavy material must be covered by water, and a steep enough grade given to have gravity give velocity to the water and exert some little action upon the material; naturally, then, were the sluice broad, 300 cubic feet of water per minute might be required, where with but half that supply of water SIZE OF SLUICE BOX 77 the sluice must be narrowed or otherwise a very steep gradient given it. Narrowing the sluice would be the most satisfactory arrangement. The length of the sluice depends upon dumping- ground and its distance from the workings; yet, were the dump close at hand the sluice must have sufficient length to thoroughly wash the alluvions, and break up the cemented gravel, and the clay. The size of a sluice is to be determined by the amount of gradient at command, the character of the material, and the quantity of water which may be used. The grade of a sluice will depend upon the fall of the ground to the dump, the character of the material transported, and the amount of water at command. The grade will vary from 2 to 15 per cent, 1 or from 2 to 15 feet in every 100 feet of length, or from 2.8 inches to 21.6 inches per box 12 feet long. The grade should be determined previously by experiment before permanently placing the sluice in position, otherwise there may be considerable loss of both gold and amalgam, to remedy which may require the raising of the whole sluice line, or, if the fall is not sufficient, its lowering. It is impor- tant that the sluice has sufficient fall, and a proper dumping ground, also it should be near the level of the ground where the dirt is to enter it. As low as ij per cent grade has been used. The sluice has advantages over any other system both for collecting free gold and the removal of barren dirt in an economical manner, consequently the attention 1 Bowie, Alex. J., p. 219. 78 DEVELOPMENT OF PLACER MINING given to its construction and the work it performs will prove remunerative. Where gravel is to be sluiced for some distance, the boxes should be stepped, in order to effect a drop that will shake up the material. Sand is apt to sink and move along the sluice in a sluggish and compact manner, and in order to shake it up and permit the heavier par- ticles, i.e., gold and black sands, to move along the bottom of the sluice to a riffle, a step here and there is necessary. The construction of a sluice box depends for details upon the size required; one 6X3 feet would require heavier sills and flooring than one 3 X 1.5 feet. The sills should be three feet apart and be twice as long as the width of the sluice, provided there is noth- ing to prevent this construction. The posts are regulated in height to accommodate the water and material; in this connection it may be stated that wide sluice boxes lessen the water pressure on the material transported, and are, therefore, more satis- factory. However, the kind of material must determine, in a measure, this point. The bottom planks should be made of clear lumber and grooved to admit of a dry pine or other tongue being inserted into the groove. These planks are placed lengthwise of the sluice and securely fastened to the sills. They should be pur- chased in widths to conform to the total width of the sluice, to avoid expense in transportation and unneces- sary delay in placing them. If a tight floor is to be had, half-seasoned plank, not less than ij inches thick should be used. The side planks should be worked in SLUICE BOX CONSTRUCTION 79 a similar manner to the bottom planks, and should extend to the sills, however in some cases one inch boards with battens are used, and in others planks not tongued and grooved but battened and caulked. The side linings should be rather thicker than the side planks, and may be rough plank. Where riffles are inserted they do not reach to the bottom plank; in all other FIG. 23. instances they should, to avoid wear on the side planks. The posts are braced every alternate sill by means of i J-inch plank strip, as shown in Fig. 23. To avoid wear upon the bottom plank, rough plank must be nailed over them. This should be hard wood, if possible; beech or maple will be found to wear smooth and uniform, where oak splinters. The cost of the sluice box will depend upon the locality, the price of lumber, nails, and labor per diem in that locality, as well as transportation. The great advantage possessed by sluicing in saving gold is due to the thorough washing the material obtains, but the necessity for the erection of retaining dams to catch the tailings has in recent years greatly retarded the system in California and consequently the output of that state. 8o DEVELOPMENT OF PLACER MINING Sluices should be at least 240 feet long and set in as straight a line as possible, otherwise fine gold and mer- cury may pass through. A sluice 500 feet long had frames 5X7 inches, with a box 60 inches wide by 30 inches deep inside, it was lined on the bottom with 2- inch planks and on the sides with i-inch boards. The floor lining was 6x6 inches blocks 10 inches long of sawed lumber. Another sluice 2000 feet long was paved with blocks. Figure 24 shows two sluice-box lines at Bullion, British Columbia, where hydraulicking is practiced. Transporting Power of Water. Water will carry dirt in suspension, and thereby increase its density; it must however have a current, otherwise it will precipitate the dirt. If the current is swift and the water deep only the heavy particles will be precipitated, but if the water is suddenly spread out and the current reduced the light particles will fall to the bottom. It is upon this principle that the sluice and undercurrent are constructed; the first being intended to transport all dirt and water that is not too heavy, and the second being for the purpose of recovering light particles of gold that are not sufficiently heavy to sink in a swift running stream. The dirt when in suspension adds to the density of the liquid and hence to its transporting power. This may be better understood by considering the momentum exerted by water moving at a given velocity in feet per second. One cubic foot of water will weigh 62.5 pounds, and if it move at the rate of 10 feet per second, will have a momentum of 625 pounds. The weight of a cubic foot of wet sand is twice that of water, 125.0 pounds. Supposing i cubic foot of 82 FIG. 24. TRANSPORTING POWER OF WATER 83 material and water passing along the sluice to be com- posed of two-thirds water and one-third sand, the weight would be 82.6 pounds, and the momentum at the above velocity 826 pounds, thus increasing the transporting capacity of the water one-third. The density of the water having been increased one-third, its ability to float material has been increased one- third; or, expressed in momentum (as far as the rock in the sluice is concerned, whose specific gravity relative to the fluid is decreased one-third as compared with water), noi pounds. The transporting capacity of such a combination is therefore nearly double that of water alone, hence the coarse and heavy material moves along, not on the bottom of the sluice, but above the bottom and below the water. This combination will move rocks that aid by their movement to disintegrate and wash out the gold from the dirt that may hold it encased or in suspension, and also prevent sand from packing. Heavy rocks will not have the same velocity as lighter, but their colliding has a grinding effect upon the material containing the gold. There are no experiments of such a nature as to formulate a rule by which the gradients being known the transporting capacity can be determined. According to Le Conte, "If the surface of running water be constant, the force of running water varies as the square of its velocity, and the transporting power of a current as the sixth power of the velocity." l Friction increases as the square of the velocity 'and as the cube of the density; however the same liquid will vary in density in the same sluice, to a wide degree. Le Conte says: "The transporting power 1 Elements of Geology, pp. 19, 20. 84 DEVELOPMENT OF PLACER MINING of water will be between the square and sixth power of its velocity." According to Smeaton, a velocity of 8 miles an hour will not derange quarry rubble stones, deposited around piers, provided they do not exceed half a cubic foot, except by washing the soil from under them. The transporting capacity of water in sluice boxes will be greater than in rivers from the fact that they are smooth and straight and of uniform width. The Size of Sluice Boxes. Sluice boxes should be calculated for carrying capacity, but in order to do this they must be calculated from the quantity of water that is to flow through them. The maximum quantity of water that can be used to advantage in a single sluice is stated to be 1000 miners' inches or 90,000 cubic feet per hour, a miners' inch being legally in Cali- fornia 1.5 cubic feet per minute. If there is more than this quantity of water at command, two sluices should be used, for a greater flow takes the workmen off their feet. It is a difficult matter to calculate the size of sluice boxes owing to the uncertainty of the size of the material they are to carry, consequently assumptions must be made and calculations made to agree with them The area of a sluice is to be calculated in square feet, thus a sluice 2X3 feet is 6 square feet in area, and if such a sluice were 10 feet long it would contain, when full of water, 60 cubic feet. If this box were given a slant of i foot, it would have a grade of i foot in 10 feet or 10 per cent, and the water would flow with a velocity found by the formula v = \/2 gh, RUBBING SURFACE 85 in which v = velocity, 2 g = 64.32 the acceleration of gravity at the end of the first second; and h the height of fall or grade which in this case is i foot. Substitu- ting these values v = ^64.32 X i = 8.02, or the velocity in feet per second which the water would have at such a grade. The flow would be, if there were no other interfering factors, 8.02 X 6 = 48.12 cubic feet per second. But there are other interfering factors such as frictional resistance, which increases as the rubbing surface in- creases and as the velocity of the water increases. The rubbing surface is the surface wet by the flowing water, and in the example cited it is 2 +3 +2 = 7 feet. This wetted surface or rubbing surface is termed the wet perimeter and must enter into the calculations as it retards the flow of water. If the channel has smooth sides such as wooden sluice boxes usually do have, the friction is less than in ditches, consequently the size and grade may be less for the same volume of water. Before entering into the calculation of the carrying capacity of sluice boxes there are some terms that should be explained. The area of a sluice box is the number of square feet or square inches in its vertical cross- section. The area is found by multi- plying the width by the depth; for example, Fig. 25, 1.5' X 3' = 4-5 square FIG. 25. feet is the area of the box; or 18" X 36" =648 square inches is the area of the box in square inches. In calculations of this kind inches must be 86 DEVELOPMENT OF PLACER MINING multiplied by inches and feet by feet, but either may be reduced readily to the other; thus 4.5' X 144" = 648 square inches; 648* and f =4.5 square feet. Another term of frequent occurrence in hydraulics is wetted perimeter. The perimeter of a figure is its boundary lines, and is measured by the length of those lines, thus in Fig. 25 the perimeter is 1.5' + 3' + 1.5' = 6 feet. The wet perimeter of a sluice box is the border of the box in actual contact with the water, thus in Fig. 25 if the water was running 12 inches deep in the box, only i foot on each side of the box would be wet, consequently the wet perimeter would be 1+3+1 = 5 feet or 60 inches. The water area in this case would be 3X1=3 square feet. The mean hydraulic radius is equal to the water area of the sluice, divided by the wet perimeter, for example, the water area in the illustration is assumed as 3 square feet and the wet perimeter as 5 feet, hence the mean hydraulic radius is | = .6 feet. The mean hydraulic radius is called at times the hydraulic mean depth, and hydraulic radius. If a sluice box 12 feet long had a water area of 3 square feet it could contain when horizontal 3 X 12 = 36 cubic feet of water. If the box were tipped so that one end was 6 inches higher than the other, the water would flow to the lower, end with a velocity equivalent to so many feet per second. If there was nothing to VELOCITY OF FLOW 87 prevent the flow of this water it would have a velocity according to the formula v = \/2 ghj in which v stands for velocity g for the acceleration of gravity = 32.16; and h for head or height of fall. Sub- stituting the values of the example in this formula, v = \/2 X 32.16 x .5 = \/32.i6 = 5.76 feet per second as the velocity. To find the quantity of water that would flow with such a head, under such theoretical conditions, all that is necessary is to multiply the area by the velocity or 3 X 5.76 = 17.78 cubic feet per second. There are several matters which enter into such calculations, that prevent the theoretical quantity of water from being realized in practice. There must be an allowance made for retardation due to friction; moreover the wetted or water area only has been con- sidered, and when transporting material the wet peri- meter will be increased from 20 to 35 per cent of the depth of the water alone. In rectangular sluice boxes, the wet perimeter is smallest and, therefore, the friction least, when the width of the box is from if to 2\ times the vertical depth. In all cases the boxes should not run more than | full. When the area needed to convey the quantity of water at the given velocity is ascertained, it is neces- sary to find what form the area shall take. The formula for finding the area is 88 DEVELOPMENT OF PLACER MINING in which a = area in square feet or square inches, q = quantity of water flowing in cubic feet per second. In the former example, the area was assumed and the velocity and quantity calculated to the conditions. This was not the best form of a sluice as the wet perimeter and consequently friction was increased: assume, how- ever, that the area was the same (3 square feet), but the bottom width was if times the height, then to find the proper cross-sectional area for this width; " Multiply the given area in square feet or square inches by 4, and divide by 7 ; the square root of the quotient will be the depth in feet or inches" Example. What will be the depth in feet of a sluice box having an area of 3 square feet, when the width of the bottom is if times its height? - Solution. - = i. 714 = 1.309. Ans. If the width is to be 2j times the depth or side, " multiply the given area in feet or inches by 4, and divide by 9; the square root of this quotient will be the depth in feet or inches." Take the area 3 square feet as before. 3 X 4 = Vi.333 = 1.15. Ans. This gives a larger area than where, the rubbing surface is not considered. Probably the tfest width relative to the depth is 2 to i. Grade. To create a uniform flow the sluice must be given a grade that will produce the required velocity. CALCULATING SLUICE GRADIENTS 89 This must necessarily vary according to the material to be transported, since coarse material will require a steep grade or a large quantity of water, while fine material will not require a very steep grade or much water. The grade given a sluice box varies from 2 to 16 inches, a box being 12 feet in length. The average grade is probably 6 inches for a 1 2-foot box, where the gravel comes from a bank that is hydraulicked. The grade once determined should be adhered to and only broken at undercurrents. To calculate a sluice gradient to produce a given flow of water use the following deduced formula v = c \/2 grs. In this formula total fall in feet or inches = sine of inclination or total length in feet or inches c = a coefficient determined experimentally for rough planks to be .8. g = 32.16, and is the acceleration in i second due to gravity. v velocity in feet per second. , , ,. ,. sectional area a r = hydraulic mean radius or - ; - = wet perimeter p Example. The water area of a sluice box is 2 square feet; the perimeter of the box is 4 feet; the grade is 6 inches in 12 feet; What will be the velocity of flow? What will be the quantity of water passing? 2 ^ Solution. r = =.<. s = -^ = .0416 4 12 go DEVELOPMENT OF PLACER MINING then by substituting in formula .8^/32.16 X 2 X .5 X .0416 = .8Vi. 337856 =.8 X 1.156 = .92 feet per second. q = va = .92 X 2 = 1.84 cubic feet per second. Ans. In the above example the grade s was given, however, to find a grade that will furnish a given velocity, the above formula is factored until it assumes the form c 2 2 gr Example. What grade must be given a box whose water area is 2 square feet, and whose perimeter is 4 feet, in order to produce a flow of 1.84 cubic feet per second. Solution. v a* * as -i-3 == .02 feet per second. a 2 c 2 2 gr ~ .8 2 X 2 X 32.16 X .5 ~ 20.58 ~ sine of inclination, and hence .0416 X 12' = .499 or .5 feet in 12 feet. Ans. In order to find the dimensions of a sluice box that will carry a given quantity of water, the empirical formula ,000 r 2 s 6.6 r + .46 is adopted by many engineers. In this formula r is the hydraulic radius, and s is the slope of the sluice, or Example (i). It is required to compute the dimen- sions of a sluice to convey 2.82 cubic feet of water per SLUICE BOX CALCULATIONS 91 second with a grade of 6 inches in 12 feet, the width of the sluice to be twice the depth of the water flowing through ito Solution. Let x = depth of water in the flume ; then the width will be 2 x and the wet perimeter = 4 x. The water area will be 2 x 2 , and the hydraulic radius O 'Y* *V 'V* r = = > consequently r 2 = . The slope is 4*2 4 = . As the discharge is to be 2.82 cubic 12 X 12 24 ry X O feet per second, the mean velocity will be - J - 2X 2 X Substituting these values in the formula 1? T* 100,000 X X 1.41 / 4 24 ^ 6.6 X - + .46 2 Squaring V* T 100,000 X X 4 24 _ ioo,oooar 6.6 X - + .46 2 then 6.56073 x + .914526 = 3 Multiplying by 3 19.68219 x + 2.743578 = 3125 x 9 . Dividing by 3125 x 6 .006 x = .0008779. If x = .383 92 DEVELOPMENT OF PLACER MINING then .063156 .002298 = .0008584, which is close enough to the second term of the equation and hence # = -383 X 12 = 4.596 inches. 2 x or width of sluice = 2 X 4.596 = 9.192 inches. 4 x or wet perimeter = 4 X 4.596 = 18.384 inches or ij feet. To prove this 4.596 + 4.596 + 9.192 _ feet 12 for wet perimeter. Area of water section 9.192X4.596 e *~* >7y = .293 square feet. 144 Hydraulic radius = ** = .191 feet. i-53 Substituting these values in the equation 2 100,000 X .I9IX a r , , 7-7 - * - ** = 9.399 feet per second and 6.6 X .191 + 46 since q = v X a the discharge would be 9.399 X .2933 = 2.757 cubic feet per second, which is approximately 2.82 cubic feet per second. All such formulas are approximate and tedious to work as trial depths must be taken. Thirty-five per cent must be added to the width of the sluice to accommodate the water and material, and 35 per cent should be added to the depth, because a sluice should not run more than | full, consequently the size obtained by the above formula should be increased 70 per cent. Example (2). It is required to compute the dimen- sions of a sluice to convey 28.2 cubic feet of water SLUICE BOX CALCULATIONS 93 per second with a grade of 6 inches in 1 2 feet, the width of the sluice to be twice the depth of the water flowing through it. Solution. Let x = depth of water in the sluice. 2 x = the width of the sluice. 4 x = the wet perimeter. = = the hydraulic radius. 4 x 2 X 2 = the hydraulic radius squared. 4 = = the slope or grade. 12 X 12 24 ~ = 24 = the mean velocity. 2 x 2 x 2 Substituting in formula .-v 100,000 r 2 s 6.6r + .46 14.1 / 100,000 4 24 y 1 00,000 X 2 96 " ) 9 i or Squaring 6.6 X 14.1 T 2 +.46 2 3.3 * + .46 ./ 3125; x 2 198.81 V 9.9 # + 3125 x 2 1.92 x* 9.9^ + 1.92 Clearing fractions, 1968.219 x + 381.7152 = 3125 94 DEVELOPMENT OF PLACER MINING Dividing by 3125 and transposing, x 6 .62983 x = .1221488. Assuming the depth of the water i foot for x and substituting this value in the left hand number of the equation, i 6 - .62983 X i = i - .62983 = .37017, which is greater than the second number of the equation and shows the assumed value is too great. Trying a value x = .9, .9 - .62983 X .9 = .5314 - .S 66 ^ = - .0354, which is less than the second number of the equation, hence .9 is too small for x and the value must be between i and .9. After repeated trials x is found to be equal to .94635, therefore, 94635 6 - -62983 X .94635 = .71828333 -.59603962 = .12224371, which satisfies the required condition, nearly. Hence x or depth of sluice is .94635 feet or 11.3562 inches. 2 x = 1.8927 feet or i foot, 10.7 inches. To verify the foregoing dimensions : The wet perimeter = .94635 X2 + 1.8927 = 3.7854 feet. Water area = 1.8927 X-94635 = 1.79115 sq. ft. Hydraulic radius = ^ - = .47317. 3-754 Substituting in the formula, , _4/ v V ioo,ooo X -473I7 X - , , ? - - - /0 ' - = 16.136 feet per second 6.6 X. 473i 7 +.46 and 16.136 X 1.79 = 28.88 cubic feet per second, which satisfies the condition of the problem approxi- SLUICE BOX CALCULATIONS 95 mately. Thirty-five per cent must be added to the depth and width of the box to accommodate the material and 35 per cent to the depth, because the sluice should not run more than three quarters full. With these calculations made as follows the sluice would have 1.8927 X 1.35 = 2.565 feet as the width; and .94635 X 1.35 = 1.28 feet as the depth. At large operations there should be at least two sluice lines, in order that work need not be stopped. It is not absolutely necessary to have two sluice lines, but it will permit mining to be carried on when one sluice is out of commission, either for repairs or for cleaning up. Where there is plenty of water and much ground to be washed, the construction of two or three sluices may be advisable. The material entering the head of the sluice box varies from mud to large rocks, consequently arrangements for impounding the material, directing it to the sluice head, and determining the grade for its movement by water are considerations which the miner must work out him- self. Usually a small dirt bank reservoir is constructed near the working face to form an enclosure that will direct the stream to the sluice head. The material moving to this latter point passes over bed rock or an improvised rock sluice. While sluice boxes have been operated on grades of inch to the foot it is better to give them more elevation where there is heavy material and sand. Quartz sand travels slowly along the bottom of the sluice and if the current is not stronger than that fur- 96 DEVELOPMENT OF PLACER MINING nished by y 3 g-inch grade the sand will lodge in the riffles and prevent the gold entering them; further it will form a bed in the sluice. In the latter case it will be necessary to keep spading the sand, which is an extra cause of ex- pense besides being unsatisfactory. One rule advocated by experienced men is to give the sluice all the grade possi- ble and at the same time retain sufficient dumping area to permit working the entire deposit. When this is im- possible there are at some places situations where hy- draulic elevators may be installed to lift the material so as to obtain an auxiliary sluice line to a dump, and in this way obtain the desired sluice grade. To prevent wear on the sluice boxes they are lined on the sides and on the bottom. In this country it is customary to use wooden blocks, iron or steel sails to avoid the wear on the sluice bottom, but the substitution of blocks of granite, basalt or other hard stones may be fully as economical where readily obtained; in fact stone pave- ments are used where wooden blocks are difficult to obtain cheaply. In addition to what has been stated concerning sluice grades if it be desired to calculate them the Chezy or Leslie equations may be used, as they give some ap- proximation to the quantity of water required to set in motion rounded stones or shingle. Leslie's formula, i> = 4 V#. Chezy 's formula, v = 5.67 V^g. In these formulae v = velocity of the water in feet per second; a = the average diameter of the body to be moved in feet; g = the specific gravity of the body. DUTY OF WATER 97 The Leslie formula ignores the specific gravity, but since it has been derived from experiments on materials that hydraulic miners contend with, it is considered suffi- ciently accurate. Experience shows that the quantity of gravel broken by a stream of water and sluiced in a given interval of time varies from i to 30 cubic yards for the same quantity of water with the same head of pressure; also it has been found that a sluice cut in bed- rock should be given twice as much grade as is given to a wooden sluice in order to carry the same quantity of material. Owing to the wide variations in the number of yards of ground broken and transported by a certain quantity of water, the duty or the number of cubic feet or yards of water used during operations can only be ascertained by close measurements over considerable periods of time. This subject of duty of water has a bearing on the effi- ciency of the plant as the following example will explain: In a period covered by 91 days, 321,100 cubic yards of gravel were broken from the bank and sluiced on a grade of i to 37.7 by the use of 14,886,400 cubic yards of water. The ratio of water used to earth removed was therefore 46.36 to i. According to the grade i part of earth should have been moved by 37.7 parts of water, therefore the efficiency obtained was about 81 per cent of the theoretical. 98 DEVELOPMENT OF PLACER MINING GRAPHICAL METHODS IN HYDRAULICS.* In this short article, the application of this method of calculation to the flow of water in ditches and in pipes will be discussed and a few curves illustrating the method will be printed. In this country, in Germany, and in England, Gan- guillet and Kutter's formula is used almost exclusively to determine the flow of water in ditches, while Bazin's new formula is used exclusively in France. Either formula may be reduced to the form of the well-known Chezy formula o = c Vrs .............................. i in which r = the hydraulic radius or hydraulic mean depth. s = the sine of the slope of the water surface c = a coefficient. Kutter's formula gives for c the values n c = 1.811 . . 0.00281 41.65+- n in which n is a coefficient of roughness. The following table gives the values of n usually used. n = .009 well-planed timber, in perfect order and alignment. * L. C. Hill (B. S.), E. E. (B. S.), C. E. COEFFICIENT OF ROUGHNESS 99 n .010 plaster of pure cement; planed timber; glazed coated or enameled stoneware and iron pipes; glazed surfaces of every sort in perfect order. n = .on plaster of cement with one-third sand in good condition; iron, cement and terra-cotta pipes well joined and in best order. n = .012 unplaned timber when perfectly continuous on the inside like straight flumes. n = .013 smooth ashlar and 'well laid brickwork; ordi- nary metal earthenware and stoneware pipes in good condition but not new; cement and terra-cotta pipes not well laid nor in perfect order; plaster and planed wood in imperfect and inferior condition. n = .015 second class or rough faced brickwork; well dressed stonework; foul and slightly tubercu- lated iron, cement and terra-cotta pipes with imperfect joints and in bad order; canvas lining on wooden frames. n = .017 brickwork, ashlar and stoneware in inferior condition; tuberculated iron pipes; rubble in cement or plaster in good condition; fine gravel well rammed, one-third to two-thirds inches in diameter; and generally the mate- rials mentioned for n = .013 when in bad order and condition. n = .020 rubble in cement in an inferior condition; coarse rubble, rough set in normal condition; coarse rubble set dry; ruined brickwork and masonry; coarse gravel well rammed, from one to one and one-half inches in diameter; 100 DEVELOPMENT OF PLACER MINING canals with beds and banks of very firm reg- ular gravel, carefully trimmed and rammed in defective places; rough rubble with bed partially covered with silt and mud; rec- tangular wooden troughs with battens on the inside two inches apart; trimmed earth in perfect order. n = .0225 canals in earth above the average in order and regimen. n = .025 canals and rivers in earth of tolerably uniform cross-section, slope, and direction, in moder- ately good order and regimen, and free from stones and weeds. n = .0275 canals and rivers in earth below the average in order and regimen. n = .030 canals and rivers in earth in rather bad order and regimen, having stones and weeds occa- sionally, and obstructed by detritus. n = .035 canals and rivers in earth in bad order and regimen and having stones and weeds in great quantities. n = .050 torrents encumbered with detritus. In the formula the value c is made to depend both on r and on s, as well as on the condition of the sides and bottom. For rather small channels in which the slope is usually between 5 = .0005 and s = .0035, the vari- ation in the value of c, due to a change in the slope is so small that it may be disregarded in the design of ditches for power and irrigation when the quantities to be carried do not much exceed 150 cubic feet per second or are not much less than twenty cubic feet per second. GRAPHIC HYDRAULICS 101 , n h / ) ( j 0. ()' / D \ ^= 1, J ) i4= : -140 : l ~/ l _X / ^ *? ^* -s --- ; = _- - = = = - / / , d / ^ .^ / / z ,^ / 1 ^ ^ ^> TOfI I/ .^ ^ 11 / y .*. ) 5^ / / 1 r / | / z , c= - ^ / / 1 / / ^ - - -120 \M 1 /" ^^ ^- | If / y ^J ** If I/ N > ^* ) 1 n / / J ^ / / k x l ., -- -110 110 " n f 1 ^ / on 1 i , rrffl s ^ / ^ ^ I ! / / i ^ ^ -100 , ^, X* 1 1 ^ ML /i/ / 7 _ ^ ^ ; = f _1 l/i/!/ s ^ ( 1) yo - /// i ., -*- I// A -X -- \ Ui\ ./ ^ -*" f// i ^/ ^ ^" too 1 / ^x- An // ^ It 1 / 2 _^ ^ ^ ; - -^ - : = = _ - ^ 7fl - / / 1 . i ' 70 1 1/ >r -- !/ y / 30-_ ft t / ^ ; x^ E ~ ;^ - -? ;= = - - = /I/ ^x 1 // I > ^j ' n ^ 7^- ^ *~ ;- ^ ^ --- ' -^ = = : i. . = = = . r i ff f 2 __ x _^ ^ ^ ^ ^ > ^ -- = !T! I ; = _ = = 40-p ^x ^ *'* - / i / ^ -B - -" / t / ^x '^ - L-^ 1 / / x* ^ --^ / f x - r i / / . Givir IN KL CURVES JG VALUES OF C JTTERS FORMUL L \. / / / ^ / ^ / f f SLOPES .001 =5.28 PER Ml. / 1/ / C = L|l + 4J.65 + ^p. // Y- 1 + 11(41.65+ ^^~ V r I Hl'yijrau i FTO3BS L n - ~T '^~T III II 1 <5 1 1 1 FIG. 26. 102 DEVELOPMENT OF PLACER MINING The curves in Fig. 26 giving the values of c in v = curs are for a slope of s = .001 and may therefore be used with but little error for slopes between s = .0005 and s = .0035. The abscissas are hydraulic radii and the ~T-| m i T: JU x' ^ u )o;> r IE CURVES ELOCITIESINFE.E FOR iNT SLOPES AND RADII. TTERS FORMULA. UGHNESS=.025 X / x < ^- J 3IVINGV T . x ^ x x* ' ^ DIFFER ^ * ^ ^ X 3 x 8 n ^ ^ ^ x x ^ ' ,( )5-j x x x RC . ? x ^x g 7 1 y / ' > ^ - 1 -. xj I ^ ^ 5 ^x ^ x 1 ^ , ^ XJ ^ / ^ ^ jX X ^. R ,9 y ^ t / x ^ ^ y > ? (X ^ ^ S-< . ^ ? ** ^ H'T 1 Q. -J /- ^ x ^ ^ ^* - ^ ^ ^x- ~/ * * x X ^ ,, -- 1 " -j~? X ^ ^ ^ ^ ^ ^ ^ f*H ^ ^ 1 C /--*/- X x ^^ I I >PH J. t- ^ X ^- "^ A \ \ ' / /_ ~? \ Z ^ ^ y! ^ X ^. -- ,( > h k> / x * ^ ^ >^ 4- t ~2- . X ^ S* _ - ^.-*' // ^ ? z ^ ^ ^ g!_| 7^7 7 .^ __ x: .. . -- ^ z Z ^ > 7 ^ -- 7?^2 t---,*^ -**!--. zLL--^ ^/ 7 X x X" x- ' , ? x* x ' ** 0] " I* ^ X^ ^ ^ ^ ^, x ^ g x" 1 X ^, -^ s . ^ ^ x^ x / x < x- ^ ** a *- ^ x* ^ X ^ ? .x 01 -- pB( / x* x^ x -^ ^ . ^ ^ x _^- "** x* X 1 x' X s* r ^ -*" 1 i-7 /* x" X 1 xj .X* ^> ** ^* ^ X X ** ^ > d rau licE I li 11 s i^i feet, 1 1 U II II 1 1 1 1 1 1 I 4 > FIG. 28. and the roughness of its bed corresponds to n = .025? Starting at a point on the axis of ordinates where v = 2.5, follow the horizontal line to the right until it intersects the curve marked 5 = .0015. From this point follow down a vertical line until the axis of abscissas is reached GRAPHIC HYDRAULICS 105 at the point where r = 1.22, which is the value of r required. c -8 - -1- 4 5 ' S ^ \ " \ *i v \ \ \ \ \ \ \ \ \ \ ^ \ \ \ \ \ \ \ \ \ \ \ y \ \ \ \ \ \ \ \ \ \ I \ \ \ \ \ \ S j \ \ \ \ V ^ \ ^ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ V \ \ \ -M \ \ \ \ ^ \ S CJ i s ^ \ \ \ \ \ \ \ \ y \ \ 3- s \ \ \ \ , s \ \ \ \ ^ ^ \ " y \ ^ \ \ \ ft* \ s \ y \ \ \ \ rl s \ \ .3 \ \ s ^ \ \ \ \ U3 \ \ s \ \ \ \ \ \ \ >. NG VELOCITIES IN FEET FOR DIFFERENT SLOPES AND KUTTERS FORMULA ROUGHNESS 035 \ \ \ V ^ s^ \ \ \ \. \ - s \ S \ \ \ \ ^ \ \ \ \ \ \ \ ^ \ \^ \ ^ \ \ V \ \ s^ \ ^ \ ^ \ \ \ \ Q \ \ s^ \ \ \ c \ \ ^ ^ \ ^ \ \ \ s s s \ \ \ \\ \ \ \ L \K ^ \ \ \ \ ^ \ ^ ^ \ s ^^ ^ s , \ ^ \ ^ >. S^ sN \ \ ^ \ s^ ^s \ k ^ ^ s^ s,\ V \ \ \ s S^y ^ \ <> ^N ^ ^ ~l n ? 3S 2 3( 8 3 "L r ^ T< a ^ i CA 8 A ^ p c > CO 1 > ^ i C] "$ q Q H The third series of curves, Figs. 30 to 35 inclusive, give the quantity of flow in second feet for slopes from s .0005 to 5 = .0030, in ditches having bottom widths 106 DEVELOPMENT OF PLACER MINING from one to ten feet. The roughness used in this series is n .025 and the side slopes 45 degrees. The short curves marked v = i.o, v = 2.0, etc., intersect the main curves at points where the velocity in the particular ditch is that of the intersecting curve. This series enables any problem within the limits of the curves to be solved with great readiness and with sufficient accu- racy for all purposes of design. The ordinates are quantities in second feet and the abscissas are depths of the water in the ditches in feet. There is one curve for each bottom width, and values between those given in the figures may be interpolated if necessary. Example: A ditch has a bottom width of four feet and a slope of s = .001; what must be the depth of water so that it may carry 50 second feet and what will be the velocity of the water in it? Starting at a point on the axis of ordinates where q has the value 50 second feet, follow the horizontal line to the right until it intersects the curve marked b = 4 feet, then follow down the vertical line until the axis of abscissas is reached at the point where the depth d = 2.83. This gives the depth necessary. In order to find the velocity, go back to the point of intersection with the curve b 4 feet. This point is between the curve of velocities marked 2.5 and that marked 3.0. Interpolating, the velocity in this ditch is about 2.55 feet per second. If the conditions are q = 60 second feet, v = 2.5 feet per second, 5 = .001, and n = .025, then both the bot- tom width and the depth are required. Starting at a point on the axis of ordinates where q = 60 second feet, GRAPHIC HYDRAULICS 107 140 CURVES GIVING DISCHARGE IN CUBIC FEET PER SECOND OF DITCHES n = .025 SIDE SLOPES 1 TO 1 S =.0005=2.64 FT. PER MILE -bO -ro e_,-^- -Depth, of. FIG. 30. io8 DEVELOPMENT OF PLACER MINING follow the horizontal line to the right until it intersects the curve marked v = 2.5. This intersection comes be- tween the curve b = 8 feet and that marked b = g feet and, by interpolating, the bottom width is 8.7 feet. From the point of intersection of the horizontal line with the curve v = 2.5, follow down the vertical line until the axis of abscissas is reached at the point where d = 2.17, which is the depth required. Hence a ditch to carry 60 second feet under the given conditions must have a bottom width of 8.7 feet and the water must have a depth of 2.17 feet. The slope of a ditch is often determined by the topog- raphy of the country. The velocity of the ditch water depends upon a number of conditions. It must be great enough to prevent the growth of weeds, and it must not be great enough to cause erosion of the canal bed. If silt and sand are carried in suspension, the velocity must be great enough to prevent their deposit. The following table gives values recommended by Ganguillet and Kutter, as giving safe velocities: Table Giving Safe Velocities in Channels. Material of the channel. Safe bottom velo in feet per secor city Safe mean vel( id. in feet per sect Soft brown earth O.O21C O.O33 -'"O v oo Soft loam oxo 0.66 Sand ^f.J-^ I.OO 1. 4. 1 Gravel 2.OO j. *f-- 2.6^ ''-'O Pebbles 3.OO 2.QA O o yt Broken stone, flint 4. .OO ^.60 r*" o* w Conglomerate, soft shale. 5.00 6-55 Stratified rock . 6.00 8.20 GRAPHIC HYDRAULICS 109 i'o' A7 7 6'^ ,j ( / 1 / / / / T ) V CURVES GIVING DISCHARGE IN CUBIC FEET PER SECOND OF DITCHES. n=.025 SIDE SLOPES 1 TO 1 8 = 0010 =5.28 FT. PER MILE. / y i ! / / 1 1 ( / / / 130 ~\ ' 7 ~JL 1 ( / *J / / / / j / i A ? / / / r / 1 / / i* n j 1 / ^ i y / 1 ^ 1 3- j i i u j / i * ) 1 / / ^ / / / / _' / | _ , i / 1 i . / j J 1 / V / I > / i 1 /' 100 1 7 _ 2 / 1 ~r r \/ i y I j 1 1 I 1 I 7 " 4- 1 > -00 /" t - ;^ -^ f-~ ^ - t / * / 1 / / -80- n / ^ / 1 j 1 / ^ J i y \ y 1 1 7 } V 1 / / / y / '-, ^ 1 1 / i 7f\ | / / J 1 > / 1 1 ^ ~j_ / V . 1 1 , / / 5 ff / / / f j 3 V / J / -fin ' ) J / / / / } > y 1 ^ ^ 1 ^ ~j / ^ f A j / y / 'v. / 2 ^ / / 1 f > > > 1 t / f / / f 7 ^. -r / / V / ^ 1 / / / / f ^ / , i t y / / f > / / f f ^ f ~C- y (l / / y / ^. on v , f / / A / i A / j > / Y ,/ y ^ /] . / / / ^/ / Y f f ^0- ^ ^ / 7^ / /: ~f ^ i L. ; i -fx yi /, / /> / 7 /. / / / / / ^ / / y yX X P*J> ^>, ^x /> -x S /> f f ' x ^ ^ ^ III :i ^r ,X ^ ^. Dep 1 i J] 4 1 1r in 1 t * ^ i= ^ -^ - ^_ 1 1 / / 1 i / / t / / f i 1 / / 1 f / / / ^ -40 V 1 I / f 1 / / / / 1 J / f / ~ i y / / y / J i / / \ / > / / f) ^ f / / / ^ . y / / / f *^ , f J f - *, / / / / / / ^ / -2 / / / / / o y / / , y / / / t y / / ^ / / / / V f / ^ s / / ^ ^ / / / y / ./ y ? . / 5 o / // / / > / S f / ^ s M > ^ ^ x x" ^x ''.' / s ^ ^ ^ g L- "i: F 5 s ^ * ^ L Le ^ H ( [ ^Vi t " 1 1 - 1 FIG. 32. in H2 DEVELOPMENT OF PLACER MINING which it is built, the loss due to evaporation will be increased by exposure to wind and sun. A dry wind blowing over the surface of water causes usually a much larger loss by evaporation than exposure to a hot sun, while the combined effects will of course cause the greatest loss. If the ditch is at an elevation above the surrounding country, the losses due to seepage are entirely uncom- pensated by any gains due to drainage or seepage into the canal. When the location may be made on side hill slopes or in bottom lands, the seepage into the ditch compensates in part for the leakage and may, under favorable circumstances, especially in an old irri- gated country, cause a distinct gain. When a ditch is first filled with water the loss due to seepage is always largely in excess of what may be expected after a short time. The ground in the immediate vicinity of the ditch will gradually become saturated and then the loss will be that strictly due to seepage. The flow from the ditch can then take place only so fast as the ground water can flow away from the canal. The movement of ground water is exceedingly slow, its velocity depending upon the character of the soil and upon the slope of the ground. In porous soils with a heavy slope to the country, the loss due to seepage will be greatest. It usually diminishes as time goes on, if the canal carries silt or fine sand in suspension. Under some circum- stances, however, when the water is very clear, this loss may increase with time. When the seepage from a ditch is excessive, various expedients may be resorted to to reduce or to eliminate completely this loss. These 1 i ill | K U l\' /^ ' h W / 5' / ' CURVES /ING DISCHARGE IN C FEET PER SECOND OF IHES IN FIRM GRAVEL SLOPES 1 TO 1 =45 .0020 = 10.56-FT. PER MILE T 1 / 7 3* 7 / I / / f / ^ CUB / ' ^ / 1 y / j 1 / DITC / / / / / f SIDE / / r y / / / i 130 6 = / y 1 i o J 1 / \ ' ^ y / I / j / / / \ / y T / 1 / / y \ ^ / / / / T T 7 / 7 , ^ / / ' ^ y j / 1 / ( 7 ^ / / / * / r " ^/ / v^ / 1 / / _ 7 - . l i / / / / / ~ 1 / J / / / / / 7 _j 1 1 ! - ' / / / j 7^ I / f , '2 90 / 1 1 / "j / j f y 1 7 , / 1 sT / = !.. i ^ M / 1 y / / y / 80 5 / / / i / 1 L_ / A 1 1 / / 1 / i j > i / y / 1 f V / ^ / g; / i j ' / 1 / \ 1 / ~2 / / / / / *::: ' 1 L i 7 /- _T -.-i =s ^= / / i 7 r / 1 ' \ / ' _/ = H o 1 f ' i i 1 I / 1 f / / X / i i / H it m 1 w d I 1 ^ / ( 1 t T / ~j ^ / / / \ f 2 / 1 ^ i / 1 ( / / / / -' 1 ^ / / ^ / / i ^ / J: -* ;=j * ~r ( /- f / ~f / i l/=2. y // / / f t ' 7 H f ^/ 2-2 / / / / ~2_ 7$V / / / / - T^Z-M / f j -20 -tf-t-t * / ^ ^ / ty// * 7 , ' tfu $ ' Z / f / / ' ' ?/ X > / -10 i/. ^^22 ** x ^ ~h 2 'x 7 / 7 ^x 7 ' ^^ ^ / 2 2 ! x ^ ^ ?1 P t 1 C ^a teri n F e j 2 ^ '^ ^ ** -x 3 1 >^ - ,^.-- s ! * 1 --, i2 1 1 FIG. 33. 114 DEVELOPMENT OF PLACER MINING vary with the conditions and with the expense the enterprise will bear. Puddling, paving, lining with con- crete (cement or asphalt) are all resorted to. In most locations, the first method is the cheapest and usually will prove satisfactory. When the velocity of the water is high, some better method must be resorted to. The cost varies between a few cents per square yard of canal bottom and sides for the cheapest methods of puddling, to $2.00 or more for expensive work in masonry or concrete. The greater cost per foot, of pipes carrying water, compared with flumes or ditches carrying the same quantity, makes their design a much more difficult problem. There are a large number of formulae which have been devised to represent the head lost in friction in a pipe, but nearly all involve the use of a variable coefficient. This coefficient is usually made to vary with both the diameter of the pipe and with the velocity of the flow, usually increasing with both as well as with the roughness. In the older formulae, the frictional resistances are made to depend on the square of the velocity of flow, while the analysis of a large number of the better experiments shows this resistance to vary, so as to give to this exponent values between 1.75 and slightly above 2.00. The lower values of this exponent are for the smoother surfaces while the higher values go with the rougher surface. In the more common formulae at least, the head lost in friction is also made to vary inversely as the first power of the hydraulic radius, while as before, analysis shows that it varies with some slightly higher power. Lampe, Tutton, Flamant, Findley . i 0' B ') 4 V , 'i " ^ / y 1 / ; RVES SCHARGE IN r PER SECOND )ITCHES E SLOPES 1 TO 1 1,20 FT. PER MILE f y 10 - \ 1 / / 1 / / 111 GIVING D. 1 7 i / l\ 1 ' \ 1 t ' 1 OF C / / / : t 1 7 \ / loO n=. 025 SID / / / i \ / I / V / 1 ' { f s I 120 \y ' / i \ / / 1 y ^ 1 7 / 1 ^ 1 / i ^ x 1 I i ] 1 ! ^ 2 / 1 1 ' 1 / / 1 / 1 / / / / If -4 / : / I / i()o / 1 / i f / 7 \ 1 ^ I 1 - , T 1 * < ^ 1 / / ' ' . j * v i 1 1 -90 : i } f I / V I ~~l 1 >o ' 7 I 1 / ^ ^ mi de o ' E 3 E t / \ . > / 1' -- E 7 1 \ 1 " 2 / / -80 -02- / i ' I 1 > t S-i ^-,'77 , . \ / i 1 1 - IE::;:: ::: 7 f 1 1 k - ..-*' 1 -I-)- .. "--ml y / -J-- - / i / ~ T7> 1 .'. / i 1 -1 -o V- 3 5i / 1 > / / -,o- - - 77^ * ^ / V ; " * / f / _ .6- - --^-ij^n 1 * / , * T / ~---~liW^ 1 / - |^ -/ f -50 - ilillmis SC^*2S(SS * t / ^53^^^*' \ 1 $ *1 * * L. , / -V * /. V/L^I*^* * " v. / * ^y , , -'0--;-- 7T --- i^_4*' Z*f* / '- J -r-f-H* vH? /^25*iZ ~ / - * ' r "7 *fr rj ,/ '72* 7*( vA * * ~ ; ' _* * .^=2, V/- ^^2^2*^2**' s * * * * A ^ Y5* y E^rf* ^ * - _; ****?2XZ ^/ */ #T'^' t / J SI !?^) X <^ <^ i = ZV.7/Z2- 2 * ! _ )d M v - ^ f/W / / ^ ^ c ^/ n >#w>> ' Jl I^S* 7 ;, X ^ - ^*f?;>*; T^pnt ii o: ') N itc 5tin Pee t "*.^, t*'* - Dept ^"" "\ till I2J FIG. 34. n6 DEVELOPMENT OF PLACER MINING and a number of others have proposed formulae of the general Chezy type, but with exponents for both r and s derived in most cases from a study of the curves formed from plotting on cross-section paper the loga- rithms of v, r, and s taken from the best experiments. The general form of the equation is: v = cr x s v ................. 3 Reduced to logarithmic form this is Log v = log c + x log r + y log s ........ 4 For any particular pipe r is a constant and if in this pipe Si corresponds to some special value of vi, then Log vi = log c + x log r + y log si ....... 5 and hence Log vi - log v = y (log si - log s) ....... 6 which is the equation of a straight line with logv and log s as co-ordinates. From this, the exponent of s - log v log ^1 log s - log si ' If from any set of experiments, values of s and v be taken and their corresponding logarithms plotted, the straight line resulting will be inclined to the axis of velocities at an angle whose tangent is y or _ g log s - ' If other values be taken from experiments made on pipes of different diameters but of the same roughness, each set on the same diameter will give a new straight GRAPHIC HYDRAULICS 117 i-o CURVES GIVING DISCHARGE IN CUBIC FEET PER SECOND OF DITCHES n = .025 SIDE SLOPES 1 TO 1 S=. 0030 = 15. 84 FT. PER MILE 120 140 1 -90 40 --3 er-m-Keet FIG. 35. u8 DEVELOPMENT OF PLACER MINING line inclined to the velocity axis at the same angle tani y. It is nearly impossible to obtain a series of experiments made on pipes all of exactly the same degree of roughness, so that it is hardly to be expected that all these lines will have, in practice, precisely the same inclination, but if good judgment has been shown in selecting the experiments, the lines will all have nearly the same inclination and the average angle may be used without appreciable error. When in the formula v = cr x s v 9 5 = 1 then v cr x 10 and Log v = log c + x log r ii If r\ corresponds to some particular value of r then Logfli = logc + xlogri 12 and therefore Logy - logz>i = x (logr - and hence logr-logri* ' This is the equation of a straight line, the co-ordinates of which are log v and log r, where log v has the par- ticular value for each pipe given when s = i or log v = o. This is the particular value given in the first set of curves by the intersection of each line with the axis of veloci- ties. The tangent of the angle this line makes with the axis of velocities will be the value of x found by sub- stituting in equation (14). GRAPHIC HYDRAULICS 119 The value of log c is the value of log v, when r and 5 are both unity, or log v = log c and v = c for this value. Hence the number corresponding to the logarithm of og of S fin 1 Log LAP SEAM RIVETED WROUGHT IRON PIPES COATED WITH ASPHALT. STOVE PIPE JOINTS FIG. 36. v at the point where this last line intersects the axis of velocities will be the value of the coefficient c in the formula and will apply to this roughness only. If for a particular series of experiments, the roughness is 120 DEVELOPMENT OF PLACER MINING nearly the same (perhaps near enough to make all of the lines of the first plotting parallel) but yet differing a little, there may be more than one line for the next plotting. These lines will be parallel or nearly so, but each one will give a different value for c. In this manner the coefficients and exponents in the general formula v = cr x s v 15 have been determined for many kinds of pipes and ditches, for this formula is as applicable to ditches as to pipes. The values obtained by Tutton and Flamant from the analysis of a very large number of the best experi- ments, both here and abroad, have been used in plotting the curves giving the loss of head in pipes per 1000 feet, when carrying various quantities of water. Curves are given for but two kinds of pipes, and should be used in the design of a pipe line only when the pipe is one of these, and not otherwise, except as a rough check on the correctness of the numerical work. If the line is a long one and the pipe is forced by the topography of the country to come near to the hydraulic grade line, the results given by the curves should be most carefully checked to prevent the pipe being laid above this grade line. Lack of attention to this essential detail has been, in many cases, the cause of endless trouble until the pipe was again relaid so as to be below the hydraulic grade line. Tutton obtained for wood stave pipe the value v = 125 r 86 *- 61 16 I 1 i \ , i \ \ \ \ -f \ \ ^ 1 \ 1 \ \ 1 y v \ 1 r^ \ I \ \ \ I \ \ i 1 \ \ ^> V \ i 1 \ \ \ s ~ \ 1 s^ \ \ r> I V \ 1 k \ u_ x, \ \ s \ o s \ 1 2 !_, \ \ i 1 Q: \ -, \ QJ Vy ^ V \ \ \ N ^ \ \ C/> \ Q_ \J ^ ^ i \ ^ ^ 1 5 3 \ \ D LLl Jl . 10 r 1 s \ \\ Q a q C 1 \ V \ r? ! S ^ \ \ I I S ^ 1 $. J I ; s \ HJ z r~ v V \ I \\\ g ; N ^ s^ \ \ \\\ . c 3 ^ \ \ 1 \\\ , 1 N S s^ \ i \\ s ! X s U 1 r \ \ \\ \ < u J r ) x, ^ \\ \ LJJ J X \ \ \\ \ 5 \ \\ s^ ^ ; V . \\\ z >v s \ \\\\ > " N \ \\\\\ _ o \ \ rW c/> 5 \ d \ ul ^ \\ \\ Q; *-* *^. \ \ \ c 5 ^^. \ I \\\ '* 1 - ^^ Sj \ \ 1 \\ ~- ^ V \\\ ~V *^ $ \ **- ^^ V \ \ ^ ^ s \ ^ i \ -v \ \\\\ v. \ \\\ - v \ \} -* -. f > V \\\ 1 ^ \ \ l\l . v \ 1 \ \ 1 15 *-. \ fj t[ \ l\ 5 X ~- ^. \l 1 S K J V )r r ^ j i a 1 S u i \ % + 37. 122 DEVELOPMENT OF PLACER MINING If for v is substituted its value in terms of q, for 5 its value - and for r its value - , and the equation be then I 4 solved for /?, the head lost in friction in the pipe 01.961 h = .0007465 I ~~^ 17 In these curves the value of h is the head lost per 1000 feet and for this the formula becomes ,1.961 ,.18 Another set of curves giving the horse-power required to drive various quantities of water through wooden stave pipes 1000 feet long is given in Fig. 38. The pipes are supposed to have their ends upon the same level and to be practically straight. The loss is then due to frictional resistances only. If h is the head lost in friction in the pipe per 1000 feet of length, then the horse-power required will be TT wqh Horse-power = -*- 10 550 where w is the. weight of a cubic foot of water, about 62.4 pounds, and where q is the number of cubic feet flowing in the pipe and 550 is the number of foot pounds in one h.p. second. Substituting these values, Horse-power = .1134 hq 20 Substituting for h its value from equation (18), ^2.961 H.p. lost per 1000 feet of pipe = .08465 - . . .21 1*8 -i 5g* i 2* > t a UJK- D tnu. O^o JJO FIG. 38. 123 124 DEVELOPMENT OF PLACER MINING Both this set of curves and the set giving the loss of head per 1000 feet of pipe in friction show how rapidly the losses increase after the quantity for each pipe reaches a certain value. This emphasizes the necessity of keeping the velocity low, thus restricting the total loss and at the same time permitting, at a small addi- tional loss, the pipe to carry, if required, a slight increase in amount. For example: if the quantity carried by a 1 2 -inch pipe is 3 cubic feet per second and this is in- creased to 4 cubic feet per second, the horse-power lost per thousand feet of pipe will be changed from 2.2 to 5.25 horse-power, or by 3.05 horse-power. If the initial quantity was 7 cubic feet per second and this was in- creased to 8 cubic feet, the horse-power lost would change from 27 to 40, a change of 13 horse-power, over four times as much. These curves are plotted so that the abscissas are in each figure the quantities of water in cubic feet per second, and the ordinates are, in Fig. 37, the losses of head per 1000 feet of pipe, and in Fig. 38 the horse- power lost per 1000 feet of pipe. Example: What must be the diameter of a wooden stave pipe 5000 feet long so that it may carry 5 cubic feet per second with a loss of head due to friction of 20 feet? The loss due to friction per 1000 feet will be ^ of 20 or 4 feet. Starting at a point on the axis of abscissas where q = 4, follow up the ordinate at that point until it intersects the abscissa drawn through the point on the axis corresponding to 4 feet. This point lies on the 1 6-inch curve and the diameter of the pipe is 16 inches. GRAPHIC HYDRAULICS 125 What will be the loss of head due to friction in a pipe 4550 feet long 14 inches in diameter when carrying 5 cubic feet per second? Starting at a point on the axis of abscissas where q - 5, follow up the ordinate at that point until it intersects the curve d = 14 inches. From this point follow along the abscissa until the axis of ordinates is reached at the point where h = 7.8 feet. This gives the loss per 1000 feet. Multiplying this loss by the number of thousand feet, 4.55, gives 35.49 feet as the total head lost in friction in the whole pipe. From Fig. 38 the horse-power lost in friction is found in the same manner from the curves. Example: The length of the pipe is 4550 feet, its diameter is 14 inches, what will be the horse-power lost in the pipe due to friction when it is carrying 5 cubic feet per second? Starting at a point on the axis of abscissas where q = 5, follow up the ordinate at that point until it intersects the curve d = 14 inches. From this point follow along the abscissa until it intersects the axis of ordinates at the point where horse-power lost = 4.45. This is the loss per thousand feet. Multiplying this by the length of the pipe in thousands of feet, 4.55, gives 20.25 as the horse-power lost by friction in the whole pipe. The horse-power which may be delivered by any pipe carrying water from one elevation to another is equal to the theoretical energy of the water in horse-power less the horse-power lost in friction in the pipe. Strictly speaking, this loss should include that due to entrance, to bends, etc., and in the nozzle, if one be used. If the 126 DEVELOPMENT OF PLACER MINING pipe be a long one, these losses are insignificant com- pared with those due to friction in the pipe and may be neglected. Let h = the difference in elevation in feet between the ends of the pipe. Then Theoretical horse-power = -*- .... . . 22 550 = -1134 hq 23 The horse-power which can be delivered equals Theoretical horse-power Horse-power lost in friction. Hence for wooden stave pipe 02.961 H.p. delivered = .1134 hq .000084651 fVjg . . .24 In this equation the second term in the right-hand member is the horse-power lost in friction in a wooden stave pipe i foot long. This equation shows that the available horse-power increases to a maximum and then diminishes to zero when 02.961 .1134 hq = .00008465 /ijr^jj 25 The set of curves plotted from equation (25) shows the general character of this variation of available horse- power with the discharge. It can not, of course, be used with any other length of pipe than 2000 feet nor other difference in elevation between the ends than 100 feet. An inspection of these curves shows that the same power may be obtajned from any pipe by allowing two quantities of water to flow. They show, also, that with - (3 OOz -V2 UJ 0- U.- Bffll VT -9000 72 .03- .7- ^8000 66- .04^ -7000 60 .05^ .8- -6000 54 06-E -5000 48^ .08^ .9- 10- 42^ 0.1 1 9- -4000 8- 36-^ i- 1* 1 6- -3000 30^ .2-= .2- .3- - 28- .3 5 26- .4- -2000 24- 22 .4 .5 .5- 4 - iHi 20- ^ .6- .7- fl ^~ 3 18- <8 ^ ^ .8- 1 ^ 3 ^g 16- 1 L 1 o ^ .9- 14 1000 "^ 14- 1 1 I 2 *- 800 12- .s * Q t< - o s Q< 4 "" fe -700 E 3- Q> "t? "" rge in Cubic ;?;? -600g fl 500 -S -400| 10- 9- 8- 7- * _ o 4- o 5 63 f !: 6 8 : 1 . ,1-1 A '*-. ^ 10-^ ^ * - r-300 P 6- r ^ .6- 3 .sj .6 5 5- 20-^ - V 4 E-200 ^ 30- 4 40- ^"1 50- .3- 3- 60^ Rfl ~ 6^ : 100 _ oil I .2-= 90 - 7 80 - - - 70 *"" 200-^ 8^ I - 60 - I _ 300- 9-1 50 LS ^ . ,1 400- 10^ FIG. 42. GRAPHIC HYDRAULICS 135 The flow in old pipes is greatly reduced, but in a way impossible to formulate with any certainty. Pipes well coated and carefully laid, carrying water reasonably clear and free from deleterious substances, may show scarcely any loss in capacity after ten years of use, while pipes with an inferior coating, carrying dirty water or water carrying in solution alkalies or acids, may in that time show a loss of 70 per cent or more. In designing a pipe line to carry a given quantity of water, this change in capacity with time should be taken into account, ^and the diameter of the pipe line be based on a future delivery of the required amount. In some enterprises, where the pipe may be in use for a few years only and first cost is of great importance, it will be safe to put in a pipe figured to carry water under present conditions, making no allowances for de- terioration unless the water is known to be very bad. On the four vertical lines (Fig. 42) are shown four quantities, discharge, diameter, loss of head or slope, and velocity. The intersection of any straight line with these four vertical lines indicates corresponding values of these four quantities; so that any two being given, the other two are determined by the application of a straight edge. This plate was taken from an article by Prof. C. B. Stewart. Example: The discharge of 3000 gallons per minute through a 12-inch pipe gives a velocity of 8.8 feet per second. CHAPTER IV. RIFFLES, UNDERCURRENTS, AND DUMPS. Riffles were mentioned under rockers and are merely traps intended to stop gold from moving along the sluice bottom. For coarse gold they are very effective, but for gold containing impurities, gold attached to rock, leaf gold, flour gold, or gold attached to black sands they are not satisfactory savers, unless aided by under- currents and mercury. There are many kinds of riffles, some of which are patented, consequently it is necessary to use judgment in their selection, as there would not be this number if it were possible to save all the gold in places. A placer miner after long experience in a certain mine stated that he did not know how much gold was in his dirt, but he knew it was worth 60 cents per yard gross to him, for that was his average saving. Some placers that have assayed rich in gold have proved flat failures as business propositions owing to the physical condition of the gold, and the writer has had several experiences where the value of a sluicing proposition has been based upon the fire assay of the concentrates that included black sands. Sluicing is a purely mechanical operation, and only free gold enters into a proposition of this kind, therefore one must know within reasonable limits what the physical condition of the gold is before attempting work. Coarse or nugget gold will travel but a short distance even if 136 RIFFLES 137 there are no riffles, provided there is an uneven place for it to lodge, however a stone moving along will dis- lodge it and then it moves to the next uneven place. To prevent this riffles are needed as otherwise the gold will eventually reach the end of the sluice. Flour gold is very fine and will be held in suspension in muddy water; leaf gold will float along the bottom of a sluice unless it can be stopped in some way, and gold attached to black sand or rock will be lost. It is no wonder then that there should be a variety of riffles, and all based upon their ability to save gold. Some prefer transverse riffles that have proved effectual in saving gold in operations with which they were once connected; others prefer longitudinal riffles for the same reason, however this rule of thumb will not suffice and as previously stated the operators must use judgment. The writer has saved gold in a longitudinal riffle that seemingly would not remain in a transverse riffle, how- ever he found that by a combination of both he could save more than with either separately. In some cases, mercury will not save gold, in other cases it will do so, therefore mercury should be used in conjunction with riffles when the latter prove ineffectual in saving gold that mercury will attack. Coarse gold does not need mercury, while fine clean gold can only be saved by its use, when however mercury is discarded in undercurrents there is a mistake made for it has been proved in rich placers like those of Little Creek on the Seward Peninsula that mercury saved fine gold, that it is customary to run into the tailings. When gold is encased in the oxides or sulphides of other metals, 138 RIFFLES, UNDERCURRENTS, AND DUMPS the combination prevents amalgamation, besides lessens the specific gravity of gold to such an extent it floats away in the current. This kind of gold material can not be saved except by concentrating the sands, or griding them so as to expose the gold, and then giving them a lixiviation treatment. Pole Riffles made of saplings split and nailed to the sluice-box floor are the crudest of riffles, and yet they are useful when better riffles can not readily be obtained. The saplings are placed transversely or longitudinally to suit the ideas of the operator. Where there is much clay in the ground nails are driven in the poles so that they will project a half inch. This breaks up the clay in a measure, and thus frees the gold. Board Riffles are shown in Fig. 43 to be longitudinal strips nailed to scantlings, that are as long as the sluice is wide inside. This riffle forms a false floor to the FIG. 43. sluice and prevents that wearing, at the same time the gold that passes in between two boards is held by the scantlings. Such riffles are readily raised when it is desired to clean up or remove the gold and as readily replaced. They are not as good for fine as for coarse gold, and if two consecutive riffles are placed so the spaces between the boards are in line, the gold may travel over the boards instead of going between them. RIFFLES Slot Riffles. Wooden riffles constructed as shown in Fig. 44, are termed slot riffles, the slots being about 2 inches wide, 8 inches long and } inch deep. Mercury FIG. 44. is placed in each slot. These riffles can be arranged so that the longer dimensions of the slots come either across or lengthwise of the sluice. The slope for such riffles should not exceed 8 inches in 12 feet, otherwise fine gold will wash over the mercury. In all riffles intended to save fine gold, the mercury used should be charged with at least some gold as mercury containing amalgam is better in holding fine gold than pure mercury. Riffles should never be charged full, as they are subject to a loss of mercury under the most favorable conditions, and the loss will be increased if the riffles are kept too full. As sand moves over a sluice bottom, and comes to the mer- cury it passes over the mercury owing to the latters specific gravity. Fine gold will also be moved over the mercury unless it is in proper physical condition for amalgamation, and it may require several riffles before the gold is finally captured. The action of mercury is not to absorb gold and form amalgam at once, but to gradually dissolve it; therefore, float gold, and what is 140 RIFFLES, UNDERCURRENTS, AND DUMPS termed spongy gold, is not easily caught by mercury on account of its lightness or a coating of some kind of material. The specific gravity of mercury being at 60 Fahr. 13.58, and native gold 19.3, or if containing silver 15.6 to 19.3, it follows that the gold will sink into the mercury bath, while sand, with a specific gravity of 2.63 to 3, will not. But mercury is not necessary to catch the heavier particles of gold, which would lodge anyway, but is useful in saving the fine gold, if it can be held in contact with the mercury a sufficient time to allow it to be dissolved. After the formation of amalgam, which is brittle com- pared with mercury, according to the amount of material it has absorbed, there is danger of loss by its floating away, and this means a loss of mercury and gold. Frequently free mercury escapes from the riffles and is lost, owing to it being subjected to shock from stones that roll along the floor and splash into the mercury trap. To prevent this the trap orifices should be made narrow so that large stones can not enter, and small stones can not enter at high speed. Stones less than one half inch in diameter have spattered fresh mercury, when allowed to splash into riffles. The kind of riffle to adopt will depend upon the size of the operation and those so far mentioned would not be suitable for a large hydraulic proposition. Mr. A. J. Bowie considers that where coarse material is washed "block riffles " have advan- tages over any other. 1. Because they make a cross-riffle. 2. They are inexpensive and durable. 3. They are convenient to tear up, clean, and replace BLOCK RIFFLES 141 The blocks for riffles may be square or round, and from 8 to 13 inches high. The squared blocks are placed in rows across the bottom of the sluice and separated trans- versely by strips of i-inch boards, to furnish a mercury trap and hold the blocks in position. The strips are nailed to the blocks, and the blocks are wedged to the sides of the sluice box as an additional precaution to prevent their moving. The longitudinal fibers of the blocks are placed upwards in order that wear and tear will be lessened, and the fibers may assist it arresting the movement of the gold. The blocks are also arranged so that they will not have their joints in the same line, or are laid as a mason lays FlG 45 bricks by breaking joints. Fig. 45 shows a sluice box with round block riffles. This style of riffle is as effective in saving gold as the square block riffle, and is also used where the material washed is coarse. The blocks should be of hard wood, and held in place by strips of boards nailed to them or to the floor. In some cases cobble stones are used at the head of a sluice box where the impact of the material is the greatest, as blocks wear much faster in this place than in the sluice proper. The objection to round blocks is, that they are difficult to obtain of the same diameters and are therefore difficult to lay and fasten in the sluice, however this objection is not sufficient to prevent their use. 142 RIFFLES, UNDERCURRENTS, AND DUMPS Stone Riffles have been used where coarse material was to be washed. Stones over the size of ones fist, and from that to stones weighing 100 pounds are considered coarse material. In large operations there is no time to assort the material and everything that the water brings to the sluice is passed through. While this is not good practice, often times it can not be avoided, par- ticularly in hydraulicking. Sluices to handle material of this kind must be lined on the sides and floor, as in Fig. 14, to prevent their being destroyed before the season is over. Riffles for saving fine gold are constructed so as to conform to the ideas of the operator, however his ideas are frequently modified to conform with the locality and means at command. If sluices are long, and riffles and amalgam traps are used, it may be necessary to patrol the line for the purpose of keeping watch over the riffles, and seeing that they do not become choked, do not leak, and finally that amalgam is not stolen. Iron Riffles. Iron rails are used to some extent as riffles. When s'o used they are laid lengthwise of the sluice with the flange either up or down. They are fastened together in such a way that the ends will not curl up, and they are also spaced with blocks between them. The objections to rail riffles are, their great weight, opportunities they offer to gold to ride the rail flanges, and their cost. There are conditions, no doubt, that would favor such riffles, for instance where the rocks are not water rounded, and where there is excessive wear on block riffles. A riffle used to some IRON RIFFLES 143 extent in the Seward Peninsula l is shown in Fig. 46. It is a light iron casting that can be readily handled. The slots are placed either longitudinally or transversely, although the longitudinal position relative to the sluice is considered to be most effective. Scale in Inches OL23456789101112 FIG. 46. The subject of iron riffles would be incomplete with- out a description of the Risdon Iron Company's patent riffle, a section of which is shown in Fig. 47. The object of such riffles is to create dead water under them and save such fine gold as mercury will not readily hold, and rusty gold that mercury will not attack. Inci- dentally, in accomplishing this purpose they do away 1 C. W. Purington, Mining Magazine, February, 1905. 144 RIFFLES, UNDERCURRENTS AND DUMPS with the use of mercury, and hence loss of quicksilver and amalgam; further, they are more easily handled and cleaned up than the ordinary riffle. The amalgam FIG. 47- retort is thereby abolished, and the gold is recovered purer, and commands a better price. The riffles are made of angle iron in sections, for any width of sluice desired. Each section is 2 feet in length, so that the sections can be readily removed for cleaning up. The angle irons are fastened at each side to the box, and are spaced so that any gold passing down the sluice along the bottom may fall into the spaces thus created. As no water comes in except from the open- ings or spaces, the water under the riffles is dead, allowing fine gold to settle and remain in the trap until removed at "clean-up." Float Gold. Float gold is either in thin scales or in such small light particles that it is termed flour gold. Mer- cury will amalgamate such gold if the mercury and gold are in proper condition for alloying. If the mercury is sickened by impurities in the dirt such as arsenic, sul- phide of antimony, manganese, etc., it acts so sluggishly UNDERCURRENTS 145 that fine gold will move over it. Float gold will be buoyed up by muddy water, particularly water contain- ing much clay, or talc. Talc seems to form a sort of scum that prevents the FIG. 48. mercury from attacking the gold until it has been washed off. Clay acts similarly, particularly if it contains much iron oxide. Spongy gold is fine gold containing pores into which clay or other material has filtered to such an extent as to greatly decrease its specific gravity, and such gold will float over mercury, where solid grains will sink through. Undercurrents are introduced in sluice lines to relieve 146 RIFFLES, UNDERCURRENTS, AND DUMPS the main sluice of coarse material and save fine gold. For this purpose a grizzly made up of iron bars, set on edge, one inch apart lengthwise of the sluice, is used for a sluice bottom, see Fig. 48. The finer material passes through the bars, while the coarser material remains on the bars. Below the bars is a coarse iron screen which checks the momentum of the coarse material and affords any gold that passes over the bars an opportunity to reach the undercurrent. The undercurrent is a shallow wooden box, from four to ten times the width of the sluice and high enough to contain the material washed into it. It is paved with either wood or stone in such a manner as to stand wear and serve as riffles. The water and material that flows swiftly in the sluice is suddenly spread over a very much larger area and this gives the gold an opportunity to settle. After the material enters the undercurrent it is spread over the entire box width by the riffles, although the inclination of the undercurrent is considerably more than that of the sluice. The undercurrent is gradually narrowed towards the discharge end, to conform with the width of the sluice into which it discharges. In some cases the large stones left on the grizzly are not permitted to enter the sluice again, but this is not always practicable on account of dumping ground. If the water is to transport the large stones the entire quantity can not enter the undercurrent, and sufficient must pass the grizzly to carry the stones down the sluice after they are removed from the screen bars. Undercurrents are at times great gold savers, for UNDERCURRENTS 147 example with a sluice 5 feet wide, and an undercurrent 20 feet wide, there was a saving of 20 per cent of the gold, and upon making the undercurrent 30 feet wide an additional 7 per cent was saved. This was accomplished without increasing the length of the grizzly, and shows the advantage of suddenly decreasing the velocity and depth of the current. There may be several under- currents in a sluice line, depending on the quantity of fine gold and the clay in the dirt washed. The grade given undercurrents varies from 12 inches in 12 feet, to 1 8 inches in 12 feet. A short undercurrent 20 feet in length should have a steeper grade than one 40 feet long, the reason being that the material will flow in a thinner stream on a steep grade. The riffles in the undercurrent will exert considerable influence on the grade, and one can only determine their action after experimenting. Fig. 49 is an undercurrent used on a dredge in Atlin, B. C. 1 The grizzly has J-inch spaces between the bars, a practice to be followed where the table is but n feet 7 inches long. The method of distributing the material passing through bars as well as the mercury traps is shown in section. The practice of using amalgam plates in such cases is questionable, since they will be scoured in all probability even should a large proportion of the material be less than J-inch diameter. This undercurrent is shown here as an explanation of % .e Hungarian riffle. Hungarian Riffles. The riffle shown in Fig. 49 con- 3ists of a series of gouges made in a 2-inch plank, so 1 Report of Minister _of Mines, 1904. 148 RIFFLES, UNDERCURRENTS, AND DUMPS staggered that they will cover the width of the sluice bottom. This form of riffle is a favorite on dredges and in some small sluice mines; it is not however superior in any way to other riffles, and must not be used where there are coarse stones, if the operator is anxious to save mercury. Mercury is usually placed in each depression. A somewhat similar riffle is made by boring 2-inch holes, J-inch deep in 2-inch planks, and staggering them so that no part of the current shall escape passing over some of the holes. Mercury is usually placed in these holes to catch and retain the gold. Stones lodge in them and as they are washed out by other stones strik- ing them there is generally a loss of quicksilver and amalgam. The Dump is one of the requisites of a sluicing propo- sition. The lack of dumping ground is often a hin- drance to hydraulic mining and in California it prevents many places from being worked. In the early days of hydraulicking thousands of tons of earth were washed daily into rivers that became clogged and changed their channels. The material broken down occupied a larger space than in the original bank, and spread over the valleys, particularly the valley of the Sacramento River in California. Fertile farm land was destroyed, making it necessary for the government to stop hydraulicking, until some method could be devised to conserve the farm lands and at the same time permit mining. The con- struction of " debris dams" by appropriations from the government and state has only partially restored the industry. Where there is a large river into which the debris may be sluiced by gravity without damaging Q m z < 2 I- -I o DC .DC O Ul _l Q V 149 150 RIFFLES, UNDERCURRENTS, AND DUMPS farm lands, hydraulicking and sluicing is still carried on, not only in California but in other localities. The lack of dumping ground for tailings will often necessitate a lengthening of the sluice. In Fig. 50 are shown a number of tributaries to the original sluice. These provide a wider area for the dis- posal of the tailings, and were necessary owing to the flat- ness of the dumping ground. In some cases, as for instance at Breckenridge, Colo- rado, it is possible to use hydraulic elevators and thus obtain a fall sufficient to sluice the waste material to a , jgi FIG. 50. suitable dumping ground. To use an hydraulic eleva- tor there is needed a large supply of water. This is lacking in some cases, and then to dispose of the debris other methods are adopted. The plan adopted at DUMPING GROUND 151 placers where both water for hydraulicking and fall for dumping ground was lacking is illustrated in Figs. 76 and 89. In cases where water for elevators was lacking, a good line of elevator buckets might be found service- able in disposing of tailing. They would require power, and this might be furnished from the sluice. CHAPTER V. WATER SUPPLY. WHERE placer mining operations are to be carried on by hydraulicking, the most important factor to be deter- mined is the quantity of water that can be depended upon. In some cases water has been conducted through ditches, flumes, pipes, and tunnels for 50 miles and in one case 100 miles. This of course requires an im- mense capital and a thorough survey of all the watersheds throughout the length of the ditch. If the ditch can be connected with a large river or lake without too great expense, the placer miner will have an ideal water supply. This however is possible only occasionally, and for the most part the supply for placer operations must be obtained from streams supplied by melting snows and rains. While this supply may be in excess of the miner's needs at certain seasons it may be so scant in the summer months that operations must cease. It is necessary in order to ascertain what definite supply can be depended upon the season through, to examine the records of snow and rain fall, and to locate places where reservoirs may be established as feeders in times of dry weather. To carry the survey out properly, reliable data must be obtained in regard to the average flow from creeks and springs and the area drained by them. In selecting 152 ABSORPTION AND EVAPORATION 153 the site for a storage reservoir me following information is to be obtained. 1. The elevation above the mine, so that a sufficient pressure will be assured for operating the giants and elevators. 2. The watershed feeding the reservoir, and the water that may be depended upon. 3. The formation and character of the ground with reference to the absorption and leakage that might occur. Absorption and Evaporation. The most desirable ground for a reservoir site is one of compact rock, like granite, gneiss, or slate. . Porous rocks, like sandstone and limestone, are not so desirable, on account of their absorptive qualities. Steep, denuded slopes are best watersheds, as then but little water will sink into the ground and the remainder will go into the reservoir. The longest slope will furnish the largest available quantity of water provided vegetation does not cause too much absorption. Bowie states that at the Bowman reservoir, in California, 75 per cent of the total rainfall and snowfall (reduced to rain) is stored. A reservoir should hold a supply capable of meeting the maximum demands. The area of the reservoir is determined by surveys and a table made showing its contents for every foot of depth, so that the amount of water available can always be known. The Bowman reservior contains about 1,050,000,000 cubic feet of water. The catchment area or watershed is 28.94 square miles. The cost of the reservoir and dams was $246,707.51. Beside the main reservoir, all mines should have auxiliary reservoirs which although com- 154 ABSORPTION AND EVAPORATION 155 paratively small are adapted for short runs. These are for the sake of insuring a supply in case of accidents to any part of the main supply ditch above them. An allowance must be made for leakage and evaporation, in the ditch line, and this loss in cubic feet per second per mile may be approximately estimated from the formula. Ma v X 5280 in which M is a coefficient that varies from 3 to 20 according to the climate. Storage reservoirs are particularly necessary where the water supply is from mountain streams which have a tendency to slack off in water during the summer months. The erection of retaining dams for such reser- voirs is part of the ditch system. The primary object of dams is to retain water; they therefore should be water tight. Dams must have firm foundations to prevent their sinking, and have their bases sufficiently wide to prevent their being moved down stream by the pressure of the water against them. p P FIG. 51. FIG. 52. It will be necessary to increase the base of a dam in width as the dam increases in height. WATER SUPPLY Fig. 51 shows an incorrect method of building a dam wherever the volume of water is variable. The pres- sure, P, of the water increases with depth, and exerts a pressure, P', which tends to slide the dam off its base. If constructed as in Fig. 52, the dam will be more stable and resist the water pressure at its base, for the weight now acts in part to keep the dam in position, conse- quently is opposed to the pressure, P', which acts to push the dam outward. Masonry dams are expensive, but masonry is neces- sary at least at the sides of any reservoir which is to contain any amount of water. The center may be crib-work, weighted down with stones, puddled clay, etc. Crib Dams. The crib dam, Fig. 53, is made of logs, bolted and spiked together. The ties, P, are FIG. 53. notched in diamond-shape, with a section of the log forming a collar. They are longest at the bottom of the crib, to be weighted down; they are also spiked to the log below them through the collar. The face logs are notched to receive the diamond- shaped collar of the ties. The face logs should have 157 i H. ^ I MINER'S INCH 159 the joints broken, and the ties should all be one above the other. This structure may be given a batter on the outside or be reinforced by an embankment of stone. The weighting down of the ties should proceed with, the building up. Care should be used to puddle the structure to prevent leakage. Large stones if laid with some system next to the face inside the crib will prolong its life considerably. The ties will not rot fast, and the face will last many years, even when rotted consid- erably, if such a system be followed. Miner's Inch. The miner's inch, up to the year 1905, was very confusing, as each ditch company in California at least had a water inch of its own. The miner's inch in California is now 1.5 cubic feet per minute, or 11.25 gallons per minute. For calculations and reference the following table will be found useful. A flow of one miner's inch of water is equal to the supply of Gallons. Cubic Feet. Per second 1871? 02 s Per minute II 2^ T e Per hour J.A'O 67? QO OO Per day y/>' IO2OO. 2l6o. Or, a flow of one cubic foot, Per second equals 40 miner's inches; Per minute equals miner's inch; Per hour equals .0110 + miner's inch. The most common measurement for a miner's inch is through an aperture 2 inches high and whatever length is required, over or through a plank ij inches thick, as shown in the Fig. 54. The lower edge of the aperture is 2 inches above the bottom of the measuring box, and 160 WATER SUPPLY the top plank 5 inches above the aperture, thus at the center of the stream flowing out there is a 6-inch pres- sure of water. Each square iinch of this opening will discharge ij cubic feet, or nj gallons of water per min- ute, a quantity that represents a miner's inch. If the slide be moved out i inch the aperture for discharge will FIG. 54. be 2 square inches and the flow of water 3 cubic feet per minute, or 2 miner's inches. Weir Measurement. To form a weir and measure a small stream place a board or plank notched, as shown in Fig. 55, at some point in a stream, where it will dam the water and form a pond above it. The notch in the plank should be twice the depth for a small quantity of water and longer in proportion if a large quantity of water is to be measured. The edges of the notch should be beveled toward the intake side, as shown. The overfall below the notch should not be less than twice its depth; that is, if the notch is 6 inches deep the overfall should be 12 inches. In the pond, about three feet or more above the weir, drive a stake, and then partially obstruct the water until it rises to the bottom of the notch, and mark the stake WEIR MEASUREMENTS 161 at this level. Then complete the weir so that all water in stream will go over the notch, and make another mark at this level on the stake. The distance between the marks on the stake, measured in inches, is the theoretical depth of flow. FIG. 55. To find the discharge over a weir of this description in cubic feet per second : 1 Let h = head in feet. b = the length of the overfall in feet. c = constant number 3.33. Q = discharge in cubic feet per second. Then Q = Vtf XbX 3.33. Example. How many cubic feet per second will flow over a weir 4 feet long, 0.64 feet deep, measured as at h or on the stake, with the constant number 3.33 ? Solution. Q = V.64 X.64 X-64 = V. 262144 = .512 X 4 X 3.33 = 6.82 cubic feet per second, or 51.15 gallons per second. To facilitate matters for the engineer, tables of weir 1 Trautwinc. 162 WATER SUPPLY measurements have .been made. The table on page 408 gives the cubic feet of water per minute which will flow over a weir i inch wide and from J to 20 J inches deep. For example, suppose the weir to be 60 inches long and the depth of the water on it to be 6f inches. Follow down the column marked inches on the left until 6 is reached; follow across the table on the line with 6 until f is reached, when 6.44 is found. Multiply this latter number by 60, which gives 386.40, the number of cubic feet passing per minute. Stream Measurement. Weirs are only adapted to the measurement of water flowing through brooks, hence larger streams are measured in some other way. To measure approximately a stream by the current and cross-section: Measure the depth of the water at from 6 to 12 points across the stream, at equal distances apart. Add these depths in feet together and divide by the number of measurements made to obtain the average depth of the stream, and this quotient multiplied by the width of the stream will give the depth of its average cross-section. The velocity of the stream is now found by measuring ico feet along the bank; marking both ends of the line, and throwing a float into the stream a short distance above the upper mark. The time consumed by the float in passing the distance of 100 feet is the recorded velocity. This operation should be repeated several times, in order to determine the average velocity of the current. One-half dozen floats thrown into the stream together and timed from the first one passing the upstream mark to the first one passing the goal will give a closer average time. FLUMES 163 Dividing this distance by the average time found for covering it gives the velocity in feet per minute at the surface of the stream. The surface water moves swifter than the water at the bottom or sides of the stream, the difference being about 8 per cent, but for approximate calculations this need not be considered. Flumes. Where the life of a mine is not more than ten years, and timber is cheap, flumes may be adopted to advantage for conducting the water from the reservoir to the pressure box. Flumes are probably cheaper to construct than ditches, and their repair is less. The calculation for the carrying capacity, etc., of flumes is the same as for sluice boxes, and need not be repeated. In most ditch lines flumes must be used for a portion of the distance, there being no other feasible method of overcoming cer- tain difficulties in the construction of the ditch. It is better if possible to carry a ditch around the head of a canon, than to cross the canon with a flume on a trestle or siphon pipes. While as a rule it is better to avoid flumes, there are situations where they can not 'be avoided, in fact a flume was bracketed to a cliff, 118 feet above the bed of a ravine and 232 feet below the top of a cliff in California. Where rock is to be excavated, or where porous ground is met, or where chasms are to be crossed, recourse must be had to the box flume. In building a flume, nothing smaller than ij-inch plank, tongued and grooved, should be used, and these joints should be white-leaded and well driven home. The sides should be made of the same material, dry pine 164 WATER SUPPLY or spruce the latter is preferable and be thoroughly fastened to the posts. The sills should not be over 4 feet apart, should project 18 inches beyond the outside of the box to take braces, and in cases where there are tunnels or trestles they should project far enough to receive a 1 2-inch plank for a walk, in order that the flume may be examined; in other situations the plank placed along the cap pieces will be sufficient. In laying the lining, care should be taken to break joints and the lining should be first-class lumber, free from knots. The grade given the flume will have some bearing on its size the steeper the grade the more water the flume will pass for a given area; this will allow con- siderable decrease in area over the area of the ditch, and consequent economy, wherever the whole grade from the source to the outlet may permit of an increase. The flume grade may be increased from ditch grade of 0.25 per cent or 13.2 feet per mile to 0.50 or 0.75 per cent. It is not always customary to employ side braces for the flume; they should, however, be used in certain situations. Wherever the flume crosses a ravine on trestles, braces will make the whole structure more rigid against wind, even when the trestles are anchored by wire ropes; again, on the side of a hill or cliff, where the flume runs full at one time and half full at another, braces will tend in a measure to prevent warping, espec- ially wherever the sun's rays strike the flume. In this connection it is well to allow a little water to run over the bottom of a flume at all times, to keep the 166 WATER SUPPLY joints tight, as the change from dry to wet conditions invariably causes leakage. The size of a flume will decide the timber to be used in its construction that is, a flume 2 X ij feet will not require as heavy lumber as one 3X3 feet in sec- tional area, except for lining. The sills, posts, and cap pieces of a flume should not be over four feet from center to center, and if three feet between centers it will be more rigid. In building flumes it is not altogether what they bear in weight, for there are other factors, such as leakage and warping, which must be guarded against, and with sills far apart the latter material elements in the problem have greater play. In the construction of a flume 3X3 feet the following timber would be required for 100 feet, the sills, caps, and posts being placed three feet between centers: 34 sills, 3 X 4 X 6' 1 1" = 235 feet, 2 inches. 68 posts, 3 X 4 X 3' 2" = 215 " 4 " 34 caps, 3 X 4 X 4' 3" = 144 " 6 " 68 braces, 3X2X3' = 102 " o " 54 lining plank, 12 X ij X 15' = 1215 " o " 9 lining plank, 12 X i J X 10' = 135 " o " Per hundred feet, 2047 feet, o inches. Per mile, 52.8 times, 108,082. Note. The above bill does not include walk or battens; add 11,780 feet for i X 3" battens and 19,720 feet for ij X 12" walking plank per mile. The lumber per mile of flume does not include stringers FLUME CALCULATIONS 167 or blocks, which must be placed lengthwise of the flume on trestles; in this connection it must be borne in mind that the foundation for a flume must be solid and level, especially under each sill. The usual size for stringers in a 3 X 3-foot flume is 4 X 6 inches, but this size must be determined by the distance between bents in the trestle, since the stringers, as well as supporting the weight of the flume and water, tie the trestle bents. With bents 12 feet between centers the stringers should be 6 X 12 inches for this area of flume. The sills should be notched for the posts; the caps should be mortised for tenent at the top of the posts, and secured by J-inch wooden pins. The general practice is to make notches for both caps and sills, using spikes to hold them. Where curves are necessary in the flume the outer side of the flume must be raised, to correspond to the degree of curvature; J-inch elevation from the lower side for every degree of curvature will be sufficient. This elevation should commence on the straight line or tan- gent of the ditch before it meets the curve, as this will tend to equalize the flow. The elevation should be gradual and reach its height at the center of the curve, and as gradually recede, until the flume again becomes straight, the object being to change the motion with the least friction possible and avoid the water pouring over the side of the flume at the center of the curve. Where- ever curves are met the sills and posts are set closer, and greater care is to be observed in placing the lining. At times it becomes necessary to run along the side of a cliff; this is accomplished by drilling holes in the 168 SIDE-HILL FLUMES 169 cliff and putting in iron brackets, upon which the string- ers for the flume rest. The brackets curve upward parallel to the posts, and are fastened by anchors to the cliff above the flume. In San Juan County, Colorado, flumes are carried some distance in this manner. Flumes should have 3 X i-inch pine battens over the floor- seams to prevent wear, and should be provided with gates at intervals, to allow water to be drawn off ; further, where snow or dirt is likely to slide into them from the mountain side, they should be covered with sheds. A common method of constructing flumes, and placing them on half-bents is shown in Fig. 56. This method was probably introduced first by the North Bloomfield Mining Company in California, in FIG. 56. their ditch line between Eureka and Milton dam. The slope of the rock in some places was such that to con- 170 WATER SUPPLY tinue the ditch would call for an enormous outlay of money, and as it was, the foundations for the 5.3 miles of flumes cost $18,920. It will be observed that the posts are dapted into the sills and caps of the flume, and that the stringers are also dapted for the bent cap. For a 3 X 4-foot flume, lined with i J-inch planks and bat- tened where the planks join the caps and legs, are 8 X 8-inch timbers, and the braces are 3 X 8-inch timbers. The cap must rest firmly on the foundation, and a proper faced hitch must be cut for the leg. In addition to these precautions holes are drilled in the rock and the timbers spiked to the rock. The stringers are 8 X lo-inch timbers dapted for the bent sill. Stringers should be placed over the bent legs, and under the flume posts, as the weight will then be transmitted properly to the ground. The sills and posts are of 4 X 5 -inch timbers. The posts are of 4 X 5 -inch timbers, and the sills of 4 X 6-inch timbers because of the notches cut. The caps are of 3 X 4-inch scantling, and the braces are 2 X 3-inch planks. Flumes are often placed on trestles to cross narrow gulches, some of which are from 25 to 50 feet high. Fig. 57 shows the method of constructing such flume- bents where the height does not exceed 20 feet. The dimensions of the flume for such situations are about as stated, as there is no necessity of increasing their depth or width if the proper grade is continued over the trestle. The trestle timbers in all cases should be cal- culated for the load they are to carry, and an engineer employed for their design and construction. In most CARE OF FLUMES 171 11 11 FIG. 57. ditch lines there is too much money involved to make any part weak, and as one part is dependent upon the other, should a break-down occur, the entire system is stopped. It is customary to i | arrange overflows at stated intervals along the ditch lines, to let any surplus water aris- ing from rains, snows, or freshets escape. These are placed about three-quarters of a mile apart, and at feeder stations or auxiliary stor- age reservoirs. When ditches have become clogged with snow after a shut-down they must be cleaned out before the water is turned in, otherwise time will be consumed, much trouble encountered, and possibly damage. Water will not melt snow fast, and will not flow through it at all, for which reason sections of the ditch must be shoveled out or washed out. In the latter case a breach is made in the ditch and the water will then float the snow through it rapidly. When cleared of snow the ditch is repaired, and a similar breach made lower down the line, and so on to the flume. Long flumes must be shoveled out, or at least a channel made through the snow in them. A. D. Gilchrist, in a paper presented to the Australian Institute of Mining Engineers in 1913, describes a color method used to measure the discharge of water from a pipe line. For the purpose one-half ounce of methyl violet is dissolved in a pint of water and injected quickly 172 WATER SUPPLY into the stream to be measured at the upper end of the pipe line. The pipe must be of known length and the time it takes for the coloring matter to pass through to the discharge end gives the velocity of the flow. This apparently crude method was experimented with by Mr. Gilchrist's students and the results compared very closely with weir measurements of the same flow of water after it had left the pipe. The pipe experimented with was 24-inch diameter, laid on a grade of 0.63 inch in 66 feet, and had a length of 25,435 feet. The time which elapsed from the introduction of the color to the first vivid show at the outlet of the pipe was 2 hours 40 minutes, thus giving the water a velocity of 2.65 feet per second and a discharge of 8.33 cubic feet per second. The weir measurements for comparison were calculated by Francis' equation, which is more complex than the one advanced in the text since it has the following expression: / ^ 6 = 3.33(^-3 v. , The flow obtained was 8.33 cubic feet per second. . Hamilton Smith's deductions reduced to the formula Q = 5.35 CB VH 3 , in which C = .603, gave 8.35 cubic feet per second. The comparison then between the color test and weir measurements is sufficiently close to warrant the use of the former, besides it is the easier way of testing the flow. Mr. Gilchrist states that the only reference to this method that he has been able to find was by Clemens Herschel in " Experiments on Conduits." He also draws the deduction that whether the distribution of velocity CARE OF FLUMES 173 over any cross-section of pipe is parabolic, or whether the velocity in the center is double that near the sides, there is no doubt that the water in the pipe moves forward as one mass, for there were about three minutes difference from the time of the arrival of the fastest color and the slowest, and this difference was largely due to method used in injecting the color. CHAPTER VI. PIPE LINES AND DITCHES. IN 1852 Edward E. Mattison, from Connecticut, with a view of economizing labor, in California placer mining conveyed water to his claim in a rawhide hose to which was attached a wooden nozzle, for spurting the stream against the gravel bank. This was the first step in modern hydraulic mining, and was so appreciated that canvas hose bound with wire and rope soon followed, and the nozzle was changed from wood to metal. The canvas hose was soon superseded by the inven- tion of R. R. Craig, who used at American Hill, Nevada County, California, about 100 feet of stovepipe. A firm in San Francisco, according to A. J. Bowie, com- menced the manufacture of wrought-iron pipe for hydraulic mining in 1856. The great difficulty experi- enced with such pipes was the quickness with which they rusted. They were, therefore, painted on the out- side, but this did not prevent their rusting on the inside. As pressure became an item of importance, the strength of the pipe was also a consideration, and as iron pipe was costly and difficult to transport, attention was given to wrought and sheet-steel pipe made in lengths suitable for transporting on mules or burros. Spiral- riveted, galvanized iron pipe was first introduced, but this gave way to riveted sheet-iron and sheet-steel pipe, that is made in sizes from 4 to 60 inches in diameter, 174 SHEET METAL PIPES il75 and is capable of resisting pressures up to 600 Ibs per square inch. The general impression prevails that such pipe is not suitable either for pressure or permanency, yet the Connecticut Tube Works have been making for municipal service a sheet-iron pipe lined with cement for some years, which they claim is more serviceable than cast iron and fully as strong after fifteen years' service. Properly constructed sheet-metal pipe, when painted with asphalt inside and out, to prevent corrosion, has lasted twenty- five years and come into general use for hydraulic mining. The numerous changed conditions to which this kind of pipe has been subjected have fur- nished reliable data in regard to pressure, diameter, and thickness of metal required for various pressures. The result of this experience, briefly stated, is, that a comparatively light sheet-metal pipe, in sizes properly proportioned to diameter and pressure, is both cheaper and more satisfactory than any other pipe for hydraulic mining. Asphalt paint, so long as it is kept intact, makes the pipe practically indestructible so far as ordinary wear is concerned. Where the coating is worn off by abra- sion in transportation, or where the pipe is subject to severe shock by the pressure of air 1 on suddenly closing the gates, or where expansion and contraction open the joints and break the asphalt, corrosion would natu- rally occur, but this can be remedied by care and an application of paint to such places. In laying pipe the shortest practicable distance is 1 Water hammering. 1 76 PIPE LINES AND DITCHES advisable, wherever the ground will permit it, and sheet pipe should always have a solid foundation along its entire length. If it must cross a small ravine it should be on a trestle with its entire length resting on plank. Short turns or acute angles should be avoided, as they lessen the pressure and strain the pipe; also, the pipe will be more affected by expansion and contraction at such points. Wherever practicable, the pipe should be laid in a trench and covered with earth, to protect it as much as possible from contraction and expansion or injury. When, laid over a rocky surface, straw or rubbish will protect it from the sun, and generally prevent freezing, especially, if the water is in motion. As a rule, pipe is not often used along the ditch line, but runs from the reservoir at the end of the flume termed pressure box down a steep incline to the mine. Pipe laying should commence at the lower or discharge end and proceed up the hill. In the long-distance trans- mission power plant at Fresno, California 1 the construc- tion of the pipe line commenced at both ends, and con- siderable difficulty was encountered in closing the gap at the center of the line. This was due to the alteration in length resulting from the change of temperature. Before sunrise the opening would be 7 feet 8 inches, but in the afternoon the gap would be 7 feet. The connec- tion was finally made before sunrise, and the pipe filled with water before the sun had a chance to expand it. There are two methods of joining pipe lengths, as shown in Fig. 58. With the slip joint the pipes are not 1 Scientific American, March 27, 1897. Fresno Power Plant. 177 i 7 8 PIPE LINES AND DITCHES of large diameter or under very high head, and when- ever this stovepipe joint is used, the lower end of each length of pipe is wrapped with cotton drilling or burlap, to prevent leaking, inserted into the next lower length, and driven in. Where slip-joint pipe is to be used an allowance of three inches must be made on each length of pipe ordered, for loss in driving the joints together. In case they leak but slightly, the leak may be stopped by throwing bran or sawdust into the pipe; or if that does not answer, dry wooden wedges are to be driven into the joints. Should the leak be large, clamps must be used which encircle the joint. SECTION THROUGH LEAD JOINT b SHOWING METHOD OF ANCHORING PIPE.ON.A STEEP GRADE WITH EXAMPLES OF LEAD AND SLIP JOINTS FIG. 59 . FIG. 58. In laying pipes where the lengths come together at an angle a lead joint, Fig. 59, should be used, or where the pressure is great or the diameter of the pipe is large lead joints should be made. This joint is made by means of a sleeve, a, which has a diameter f inch larger than the pipe and into the space, b, hot lead is poured. FLOW OF WATER THROUGH PIPES 179 With heavy pressure on steep grades, the pipe sec- tions should be wired together, and lugs should be fur- nished on the outside of the pipe for this purpose. Anchor wires should also be attached to the pipe and to a stable object at intervals on heavy grades. It is customary to make the pipe of large diameter and of light weight metal near the pressure box, and to decrease the diam- eter and to use heavier metal toward the discharge, At the Fresno power plant the pipe line was 4200 feet long, with a head of 1411 feet, giving a pressure of 609 pounds per square inch. This was built in three sec- tions, as follows : ist Section. 1820 feet, 24-inch riveted pipe, first half No. 12 steel, and the second half J-inch steel plate. 2d Section. 400 feet, 20-incJi diameter, lock- jointed welded pipe. 3d Section. 1800 feet, 2o-inch diameter lap- welded f-inch thick pipe, with flange joints and rubber packing. This column of water weighs about 317 tons, and has a thrust of 93 tons, when issuing from a i^-inch nozzle at a speed of 9000 feet per minute. Air escaping from the Fresno pipe nozzle makes a noise which can be heard several miles. The noise is due to the expansion of air as it leaves the nozzle in bubbles that have been subjected , to the heavy pres- sure. ^L The Flow of Water Through Pipes. Head of Water. By head of water is meant the difference in elevation between the inlet and outlet of a pipe, plus the height of the water above the center of the pipe inlet. Water) pressure is due to the head, and is derived from the i8o PIPE LINES AND DITCHES weight of the water, hence the higher the head, the greater will be the pressure. The pressure due to a column of water i inch square and 12 inches long is at ordinary temperature about .434 pound. For approxi- mate calculations the pressure may be considered .5 pound per square inch for each foot in height. Loss of Head. Friction in pipes may diminish the pressure due to the head and hence the power in three ways. i. Resistance to the flow of water is greater in small than in large pipes. The resistance does not arise directly from the rubbing surface, but is due to a layer of water that adheres to the pipe and acts as a drag on the current. The amount of drag is greater in rough than in smooth pipes, and in short bends than in long bends. The circumference or frictional rubbing surface or perimeter of a i-inch pipe is 3.1416 inches, while the perimeter of a 2-inch pipe is 6.2832 or twice that of a i-inch pipe. The area of a i-inch pipe is .7854 square inch, while the area of a 2-inch pipe is 3.1416 square inches or 4 times as great. From this it is deduced that by increasing the area of a pipe the frictional resist- ance is decreased, for in the 2-inch pipe with twice the rubbing surface of the i-inch pipe, 4 times the water will pass the head being the same. The loss of head due to friction in pipes is difficult to calculate, in fact it is not: necessary to make such calculations, as they have already been made and tabulated for the use of engineers. (See table on p. 409.) The formula given LOSS OF HEAD 181 for friction of water in pipes is the simplification of Weisbach's formula by Coxe: p _ X 5 v - 2 ^ looo d F represents the friction head or total loss by friction in feet; / the length of the pipe line in feet; d the diam- eter of the pipe in feet; v the velocity of the water in feet per second. 2. The flow of water through pipes depends upon the diameter and length of the pipe, and the velocity due to the head principally, but in addition there is a loss of head due to power absorbed in giving the water a uniform rate of flow or as it is termed selling it in train. 3. Another amount of power is consumed in over- coming the resistance due to the water entering the pipe. A series of 88 experiments made by Hamilton Smith, Jr., on the flow of water through circular pipes of various diameters from J inch to 4 feet are reduced to the formula: v =>m I where v = velocity in feet per second, d = diameter of pipe I = length, A' = effective head, m = variable coefficients. The effective head h' was derived from the total 182 PIPE LINES AND DITCHES liead h as follows, c being the coefficient of contraction at entrance : in which g = acceleration of gravity. Strength of Pipes. Pipe lines generally involve considerable outlay, and must be proportioned for strength as well as capacity. The bursting and safe strength of iron and steel pipes, and their construction should be understood, although the table on pp. 336-338 gives the safe working pressure for double-riveted pipe up to 42 inches in diameter. To calculate the safe working pressure for iron or steel-plate pipes, the following formula advanced by Professor Rankin may be used. In the formula P is the safe working pressure in pounds per Square inch; T is the tensile strength of the plate, iron being taken at 48,000 and steel 62,000 pounds per square inch; t is the thickness of the plates in decimals of an inch; c the: factor of safety usually assumed as 4; / is the propor- tional strength of plates after riveting, the factor being .7 for double-riveting and .5 for single riveting; R is the radius of the pipe in inches. - Example. Having a head of 75 pounds per square inch, of what thickness should a double-riveted 36-inch diameter iron pipe be> with 4 used as a factor of safety? STRENGTH OF PIPES 183 Solution. Factoring the equation for /, the for- mula becomes / = -r - and by substituting the values given 4 X 75 X 4f t L2 - a A r /48,ooo X i6\ p ) * f = ( x6 ) * - 7 == 75 pounds 48,000 X .7 Example. What will be the safe working pressure for a pipe 36 inches in diameter, made of .1 6-inch sheet iron and double-riveted, where using a safety factor of 4? T 4x36 pressure. Ans. When sheet-iron pipe is left to the option of the maker the lengths are generally 27 feet. When Sit is to be trans- ported by wagon the lengths are 20 feet. When the pipe is for heavy pressure and mule packing it is made in sections of 24 to 30 inches in length, rolled lengthwise and punched, with rivets furnished to put the pipe together on the ground' where laid. Sheet metal for this purpose can be riveted cold, with the ordinary riveting and flanging tools. Sheet iron or steel in this form has a discount of 30- per cent from completed pipe. After riveting, the pipe should be tarred or painted with asphalt and allowed to dry. Pipe should be dipped in asphaltum heated to a tem- perature of 300 F. and allowed to remain in the bath until the metal attains the same temperature. The material for pipe construction should have No. 8, 10, 12, 14, 1 6, and 18 B. G., thicknesses, according to pressure, 184 PIPE LINES AND DITCHES and iron plate will usually prove more satisfactory than steel plate, as the latter oxidizes and flakes readily. Pipe Elbows. The additional head required for bends is given on pages 314 and 318. No bends should be allowed in a pipe line, where the pipe is long or the pressure heavy, that have a radius less than five diame- ters of the pipe. The simplest rule for calculating the loss of head due to bends of various angles in a pipe is H = .0152 V 2 K. in which K is a coefficient to be taken from the following table: Angle of Bend 20 40 60 80 90 100 120 K ... 046 139 364 74 98 1 26 1 86 When the radius of the bend is greater than five diam- eters of the pipe the loss may be calculated by multi- plying the number of degrees in the angle by the square of the velocity in feet per second, and dividing the product by 88,489. Example. With a bend having an angle of 100 and discharging water at a velocity of 20 feet per second, the loss of head, will be 20 2 X 100 88,489 = .45 feet. When the radius is less than five times the diameter, fairly accurate results may be obtained, by multiplying the square of the velocity of the water in feet per second, WATER GATES by C, a coefficient having the following angles: 10 C. = .000109 20 C. = .000466 50 C. = .003634 30 C. = .001134 40 C. = .002158 60 C. = .005652 70 C. = .008276 80 C. = .011591 90 C. = .015248 There has not been sufficient investigation on this subject to enable the engineer to make exact allowance FIG. 60. for friction due to bends, and all calculations are there- fore approximate. Water Gates. Pipe lines would be incomplete with- out water gates. A section and cross section of a gate valve is shown in Fig. 60. The gate, a, slides vertically up and down, so that when fully open there is practically no interference with the flow through the pipe. The i86 PIPE LINES AND DITCHES valve gate casing, b, is cast iron, reinforced by a web in its circular part and with a stem, c, terminating in a screw. By means of the movable nut provided with levers in the top of a yoke, d, the screw is made to turn and move FIG. 6 1. the gate upwards or downwards. The lower end of the stem is fitted in a box collar, e, in order that it may turn freely. Whenever a junction is made with another pipe AIR VALVES 187 line the custom is to fork the lines rather than use elbows. Two such gate valves are then used, one in each branch pipe, as shown in Fig. 61. All gate valves should have outside yokes and coarse screw threads to prevent quick closing and the consequent water hammer. Air Valves. There should be two working faces in any hydraulic mine, so that one may be worked while the pipe is being advanced in the other. This is accom- plished by running the main pipe line into the center of the mine and using a Y which has water gates on each branch line. The stand pipe shown in Fig. 61 is an air chamber, supplied with a pop valve at the top that allows the air to escape after it reaches a certain pressure. Its object is to prevent water hammer, and possibly damage to the pipe line, also to collect air before it leaves the pipe nozzle. To allow the escape of the air from a FIG. 62. pipe line while filling, and also to prevent the formation of a vacuum and collapse of the pipe in case of a break i88 PIPE LINES AND DITCHES in the pipe line, air valves are required. The valve shown in Fig. 62 is automatic in its action, and quite simple in comparison with some. When the water fills the pipe it raises the valve, a, and when it leaves the pipe the valve, a, immediately drops and allows air to enter, thus preventing a collapse. Air valves of this descrip- tion or some other should be placed wherever there is a knuckle or high place in the pipe line and where air is likely to accumulate or a vacuum occur. At all low places similar blow-off valves should be placed. The Pressure Box. In order to prevent sand, gravel, sticks, and rubbish from going into the pipe line, and FIG. 63. particularly to prevent the admission of air, a pressure box is used. The pressure box, Fig. 63, should be large, and the water should stand at least 4 feet over the entrance to the pipe in order to prevent the admis- sion of air. The pipe should be funnel-shaped where the water enters it, if it can be placed horizontal, but if it can not be so placed the pipe should be as in the cut, and firmly anchored. There should be a gate, G, at the reservoir or flume THE PRESSURE BOX 189 at the head of the pipe line to cut the water off. There should also be pressure indicators and water regulators which will regulate the flow. The cheapest gate at the head of the pipe line or along the ditches and flumes where pressure is not excessive is constructed of plank about as long as the water course is wide, and 8 inches high. These are placed one above the other, in grooves, so they may easily be removed and replaced. The grooves are formed by nailing 2 X 3-inch plank to the side of the flume, and through these guides the gate planks are lowered and raised from the top. Consider- able trash is at all times moving with the water in the ditches, hence for floating rubbish the flume and pressure box should have inclined bars of wood or iron to prevent it reaching the pipe. Sand is collected by placing iron bars, S', across the bottom of the flume over a box, SB, let into the bottom as shown. To prevent sand and gravel from entering the pressure box, there should be an increased depth and width to the ditch for at least 100 feet back from the pressure box. There should also be a small gate, G', in the sand box for blowing out, and the pipe, P, should be from 2j to 4 inches above the floor of the pressure box. The gate, G, regulates the flow of water into pipe, P, and shuts it off entirely if a small waste gate is placed on the flume side. The same construction for gates may be used in dams, flumes, and ditches. Water gates are expensive when made of metal, but in some instances they will be required in the pipe, near the pressure box. Under heavy pressure they are not easy to work, and wear out fast. igo PIPE LINES AND DITCHES Filling Pipes. Care must be taken when filling pipes to introduce the water gradually, in order to pre- vent serious accidents. For this reason it is probably a good plan to place a gate valve in the pipe below the pressure box, in order to regulate the intake flow. Air will enter a pipe in surprising quantities, and in one instance enough air was taken in at a power plant to run an engine or a rock drill. The water before it enters the pipe should be free from air and should enter quietly, this as mentioned can be accomplished to some extent by placing the pipe some distance under water, say 4 feet. Before filling the pipe all stones and rub- bish are to be removed. Ditch Lines. Surveys are necessary to the design and construction of a ditch, as the course of the ditch is confined to narrow limits by the topography of the country through which it passes. The survey will begin at some point very near the storage reservoir site, and will generally follow the same valley as the stream that was impounded for a consider- able distance. It will be found that careful surveys in such operations pay because more accurate work can be done in their construction. As far as alignment is concerned, this survey does not call for any great degree of accuracy, the leveling being of much more impor- tance. Errors are liable to occur in leveling. There, fore, when the alignment has been completed and leveled, check levels should be run back over the entire line. It will not be necessary, to verify the entire profile, a check on the benches being sufficient. All important tribu- taries should also be surveyed, carrying the survey to an DITCH LINES 191 elevation approximately equal to that of the reservoir site. The approximate length, together with the total fall obtained from this survey, will enable the engineer to make a preliminary design of the section and grade for the ditch. A trial line for the ditch can now be run. For this purpose, suppose a grade of 13.2 feet to the mile is decided on for the slope of the ditch. The tangent of I 3 2 the angle corresponding to this slope is -^ = .0025, 5280 which corresponds to an angle of nearly 9 minutes. Having a transit provided with a vertical limb, let the telescope be depressed to this angle and clamped. When the transit is set up, let the target of a leveling rod be set at the height of the telescope of the transit from the ground. This can be sufficiently approximated by holding the rod alongside of the transit and sighting across the wyes. Let the rod now be taken as far ahead as possible and moved along the ground, up or down hill, until the center of the target is bisected by the horizontal cross-hair of the transit. The foot of the rod is on the ground falling at the desired rate, and a plug should be driven at this point and the distance measured. The direction will be ascertained by the needle, as this will be sufficiently accurate. From time to time measurements will be taken to convenient sta- tions on the line of the survey, if one has been made, as a check. It will be well to carry this line along, follow- ing all the indentations and tributary valleys, for in this way the length of a line following the natural surface of the ground for its entire distance will be obtained. ex 192 DITCH LINES 193 It will be very rare that this line is actually followed by the ditch. Valleys will be crossed by trestles or siphons and hills will be tunneled, but only in this way can an estimate of the comparative advantages of alternative ditch lines be compared. When an approximate location of the ditch has thus been determined, the line will be accurately re-run and leveled over, so as to establish the final location and make a more nearly exact estimate of cost. The material in which the ditch is excavated will place restrictions on the velocity of the water. The velocity should be sufficient to prevent the deposition of silt and not so great as to erode the bottom and sides of the ditch. The grade necessary to maintain a uniform velocity within the desired limits will depend on the interior surface of the ditch, being very much less for one having a smooth lining than for one having a rough lining. The area of cross section also is a function, for the water in a large and deep ditch will move with a greater velocity under a given grade than that in a smaller and shallower one having the same grade. The form of the cross section also exerts an influence on the velocity of flow, so that the determination of the grade becomes a complex problem, depending on the desired discharge of the ditch, its rubbing surface and form, and the dimensions of its cross section Gravity is the sole force that acts on water in a ditch to produce the motion which takes place. The inclination of the surface of the water in the ditch is the immediate cause of motion, being that 'which enables gravity to act. 1 94 PIPE LINES AND DITCHES It is evident that the steeper the ditch grade the greater will be the velocity of the water; and as this grade is determined by the ratio of the vertical height to the distance in which it is overcome, it is evident that the accelerating force producing velocity will be expressed by the ratio -j , in which h = the difference of level between the two extremities of the ditch and / == the distance, usually measured horizontally, separating the two. If there were no resistance to the flow of water through the ditch, the constant accelerating force would cause the velocity to go on increasing indefinitely. Owing, however, to resistances the water soon acquires a con- stant velocity, provided the ratio remains constant. If There are resistances that increase in intensity with the increase of velocity, so that after a certain time the increasing resistance just equals the increasing accelera- tion, and the velocity then becomes constant or assumes a permanent regimen. The laws bearing on the subject of the flow of water in ditches, may be expressed as follows: I. The resistance for any given velocity is propor- tional to the wet perimeter or the surface over which the water flows. II. This resistance affects the entire volume of water being greatest for the film in immediate contact with the wet perimeter, and becoming less and less for the films and threads more remote from that surface. III. The greater the surface in contact with a given DITCH FORMULAE 195 volume of water, the greater the resistance becomes; con- versely, the greater the volume subject to a given resist- ance, the less will the velocity be affected. IV. The resistance is nearly proportional to the square of the mean velocity of flow. V. The resistance varies with the nature of the ditch ground, being greater for a rough surface and less for a smooth one. Let h = difference in level between ends of the ditch or any two cross sections of the ditch. I = horizontal length of that portion of the ditch included between the sections whose difference of level is h. g = grade = ratio - / a = area of water cross-section. p = wet perimeter. r = hydraulic mean radius = ratio P c f = coefficient depending on the ground in which the ditch is excavated. v the mean velocity of flow. Then, the resistance to flow may be expressed by the equation ha = c'lpv 2 , from which the formula is derived. By replacing the factor y by an equivalent factor, c, then v = cVrg. 196 PIPE LINES AND DITCHES Form for Ditches. It is evident from the formula that the velocity increases with the hydraulic mean radius r = , and that therefore the most favorable shape of cross section will be the one in which a given area is enclosed by the smallest wet perimeter. In the case of a ditch, this section would be a half circle, since the circle is that geometrical figure which encloses the greatest area within a given perimeter. In the case of the circle, the value of the hydraulic radius is and, since both the area and the wet perimeter of a half circle are, respectively, equal to one-half of the area and wet perimeter of a circle when running full, the ratio for the half circle is also equal to The half-circle form is an impracticable form for a ditch, since it could not be constructed and maintained unless lined with masonry or some other permanent material, and even then the constructional difficulties would generally render this form inadvisable, as entail- ing a considerable expense for labor without a correspond- ing economy of material. An approximation to this best form is half a regular hexagon, in which D being the diameter of the circumscribing circle. This form would also require a permanent lining if it were TRAPEZOIDAL DITCHES 197 applied to an earthen ditch, and would not, therefore, always be consistent with the character of the ground and the velocity of flow. The form of a ditch, there- fore, should not be hexagonal, from the fact that unless the sides are of hard rock they will wash considerably. Ditches having the trapezoidal form can have their sides made to conform with the natural slope of the material and its hardness. Again trapezoidal ditches offer less rubbing surface for equal water areas than rectangular ditches. On the other hand the trapezoidal form is less adapted to withstand losses of water from percolation and evaporation that occur, owing to the large area of water surface exposed to the air, and its largest area of ground exposed to the pressure of water. The re- FIG. 64. lations existing between the various dimensions of a trapezoid are best illustrated graphically. The area of a trapezoid is found by adding together the length of the parallel sides, dividing the sum by 2, and multiplying the quotient by the perpendicular height ec. Thus in Fig. 64 area = The angle of slope eac is equal to = cot. eac. The peri- C 198 PIPE LINES AND DITCHES meter is ac + cd + db. The side ac is the hypothenuse of the right triangle aec, and hence ac = \/ae 2 + ec 2 . The relative slope of the sides of a ditch are expressed by stating the ratio of the base ae to the height ec of the triangle aec. Size of Ditches. The following table is composed of subject matter obtained from Molesworth's Pocket Book" and from C. C. Longridge, "Hydraulic Mining." It will be found useful for comparison between the different ditch sections, and for ascertaining the size of ditches to carry a given quantity of water. Angle a Degrees. Slope of Sides. Vertical Depth. Width at Top. Width at Bottom. Perimeter p = Va X Factor, Factors. 90 oo' Vertical 77V / .4i4V^ 1.414^/0 2.828 78 4i' .200 734\/a 5io\/a i.2i7Va 2.713 75 58' .250 734\/a 533\/a i.i6iv / a 2.692 7i 34' 333 752\/a 58oV^ i.o79 V / a 2.656 63 26' .500 7S9AA .697^ 93 8 \/a 2-635 60 oo' 577 7 6o \/a 755\A 877V 2.632 56 19' .667 759^0 .824Vo; .8i2v^ 2-635 53 8' 75 757 Va 892^/0 753\/a 2 . 645 51 20' .800 753Va i . 96o\/^ 724\/a 2.654 45 oo' .000 74Q\/a 2.o92 v /a 6i3\/a 2.704 40 oo' .192 722\/a 2.246\/a 5 2 5\/a 2.771 36 52' 333 77\A 2 -557\/a 47i\/ 2.828 35 oo' .402 697x/a 2 . 430 \/a 439Va 2.870 33 4i' .500 .689^ 2.465\/a .4i8v^ 2.989 30 oo' 1.732 664v^ s^av^ 356\/a 3.012 26 34' 2.OOO '6$ and -2? = 238 pounds of powder as the charge. O J The length of the main drift heading should be longer than the bank is high, thus making the distance to the surface the line of least resistance to the blast. The charge should be placed about half and half in each end of the cross drift and walled in. The tamping must be done carefully and carried to the main drift, and at this point a wall should be built and more tamping added. In case the explosive gases are given space to expand, they will not be as effective as when they make their own space for expansion, for which reason ram- ming the tamping is not objectionable. Wherever possible the charge should be fired by an electric bat- tery and not by fuse. In case the explosive is black powder, then a piece of dynamite with a fulminate cap inserted should be used as a detonator instead of relying on the fuse to fire the powder. Fuse is an uncertain quantity, for it is apt to be cracked in unwinding and jamming; again, there is no certainty of the charges at each end of the cross drift 244 EXPLOITING PLACERS being discharged at the same time; and further, it will be liable to injury during tamping operations. If it must be employed, then double or triple tape fuse is laid in duplicate lines in order to make sure of a successful blast. Small blasts are less economical than large ones; however, a series of small blasts are more effective than one large one. It will be policy, therefore, in case the face of the bank will permit, to drive two or three drifts about 75 feet apart and make the cross drifts at their ends 25 feet long each way. Each cross drift should be loaded the same and the entire series fired at once. In some cases there is one drift, and from this two or three pairs of drifts are driven at right angles. The powder must be now proportioned to the yardage each charge is to break. The charges must be properly tamped and all fired at once. Judgment must be used in dealing with this kind of blasting if the maximum work is to be obtained with a minimum expenditure of powder. Experiment and close observation of the work accomplished will prove more satisfactory than any definite rules that may be laid down for the use of powder. Mining in Alaska. In Alaska the summer season is too short to thaw the ground to any great depth; further, in such cold climates the surface is usually covered with moss that prevents the sun's rays from penetrating the earth. When the placer gravel is not over 12 feet thick the moss and all other vegetation is stripped from surface and under such conditions the sun will thaw the ground from i to 2 feet per day. The muck does not thaw as fast as the gravel. How- ever, as fast as a layer of dirt thaws it is removed by MINING FROZEN GROUND 245 ground sluicing, until the pay streak is reached. The pay streak is washed in sluice boxes. Where the placer ground is more than 12 feet deep, shafts are sunk to bed rock. The top or muck soil is picked and shoveled, but when gravel is reached it is either thawed by wood fires or by steam points. A wood fire in a shaft will thaw from 8 inches to i foot per day, provided there is not too much frozen water in the gravel. When bed rock is reached, drifting is commenced, and either wood fires or steam used for thawing. A good wood fire will thaw from 12 to 18 inches into the face, and a fire 30 feet long doing this amount of thawing is good work for two men on a 4- foot pay streak. Steam is now more generally used in Alaska than wood for thawing, although the cost of coal is $25 per ton, on the Seward Peninsula. The plant consists of a boiler, connected with steam pipes leading to the face. At this point a manifold is used, to which several steam hose are fastened. To the free end of each hose a nozzle is attached, called a " point." The point is from 5 to 6 feet long, about ij inches in diameter, with jet holes A inch in diameter at the pointed end, and a drive end at the other. The hose is attached to a tee near the drive head. The points are placed about 3 feet apart in a breast, and are gradually driven in as the steam thaws the ground. They are allowed to stand 5 or 6 hours under a steam pressure of 20 or 30 pounds per square inch, when they are disconnected. The ground is picked down, loaded into buckets, hoisted to the surface, and dumped on a pile as fast as it is thor- 246 EXPLOITING PLACERS oughly thawed. As soon as the spring thaws com- mence, the pile is sluiced in boxes. Scrapers attached to horses are used to carry dirt from the pile to the head of the sluice, and on account of the flat ground scrapers are also used for spreading the tailings. As a rule, very little timbering is required in frozen gravel ; in fact, it is safer than solid rock. It is customary to drive rooms 400 feet long and from 30 to 70 feet wide without any timber to support the roof. In the tundra mines on Little Creek the gravel is frozen to bed rock which is at a depth of 120 feet. Gold was discovered in Georgia in 1828, also the first accounts of the use of the rocker in America are credited to Dahlonega, Georgia. While the Californians de- veloped hydraulic mining, we are informed by Claude Hafer 1 that nozzles and ditches were used in Georgia so early as 1868. This does not precede the rawhide hose of Mattison, although it shows that at this time hydrau- licking was firmly established. The system adopted in Georgia consists in cutting into the hillside along the strike of the mineral deposit with a giant, after which the broken down material is swept by the current into a flume through which it passes to a mill generally located on a stream bank and operated by water power. The bottom of the flume is fitted with racks that act as riffles and collect the coarse gold. At the mill the fine sand and mud are run to waste, the coarse rock is broken with stamps and the gold recovered as far as possible by amal- gamation. By this means the low-grade saprolite ores have been cheaply treated which without the aid of the 1 (Mining World, Vol. XLV, No. 14, p. 611.) MINING FROZEN GROUND 247 giant could not have been profitably worked. The giants operate under a head of from 100 to 200 feet and are connected by pipes with ditches along the ridges above. In order to reach elevation and so obtain head the ditches are many miles in length as they follow the surface contours. At the present writing there being more returns by converting the ditch water into hydro-electric power not much is now used for gold mining. On one ditch line which was 42 miles long, tunnels were driven, and an inverted siphon used to carry the water, features which show that the California method was closely followed. In the southern states of South Carolina, Florida and to a less extent in Tennessee, the giant is used for strip- ping the surface above phosphate deposits, and then for sluicing the phosphate rock carrying material to sumps from which it is pumped to washers for further concen- tration. The power or pressure for the giants is obtained from centrifugal pumps, also the movement of the ma- terial from the sump to the washer is accomplished by similar pumps. Two articles, one by E. H. Sellards, State Geologist of Florida, and one by James A. Barr will be found in "the Transactions of the American Institute of Mining Engi- neers for 1914, that deal with hydraulicking of phosphate deposits. The value of the giant for stripping ground from mineral deposits under some conditions is now fully established and found to be the most economical method where water and fall are to be obtained. To return to the subject of drift mining it is to be 248 EXPLOITING PLACES understood that it is comparatively slow work and there- fore expensive because the broken material must be carried from the mine and washed outside. Recently in the Magalia District in California, where drift mining was once extensively practiced, the plan which is believed to be experimental is as follows : Water is piped to the face in the Mineral Slide mine, where it is spurted against the ground and allowed to flow through the drift to daylight in sluice boxes. Previous to this it was the custom to tram the dirt to a hopper and wash it from the hopper at the mouth of the drift into sluice boxes. Butte County, California, in the vicinity mentioned, has had several drift mines in operation for many years, but most of the work is done on the order of pocket mining, as in this vicinity the richest drift in California has been found. The Magalia mine is said to have carried gold that panned from $80 to $100 per shovel in one part of the channel. The Emma Mine also was noted for its richness. Undoubtedly there will be considerably more gold recovered from this district when engineers turn their attention to some better method of recovery than is now being practiced. CHAPTER IX. EXPLOITING PLACERS. (Continued.) Mining in North Carolina. There is a belt of chlor- itic schists extending from Georgia to Nova Scotia in a northeasterly direction. The schists, which are meta- morphosed and impregnated with quartz stringers, have been assigned by geologists to Cambrio- Silurian times. The quartz in these schists is highly mineralized in places, and carries gold, silver, copper, lead, arsenic, antimony, and possibly other metals. In some localities this belt of rocks has been altered, particularly in North Caro- lina; while in other localities it is evidently unaltered, particularly in New England. Owing to the physical condition of these rocks in North Carolina they are in several localities termed placers, and are worked as such; but in order to work them profitably, methods that are economical and efficient must be adopted. While the placers are considerably richer than the majority of western placers, nevertheless they are not as readily worked. The gold is in a fine condition, but that is not the entire reason why it cannot be recovered by methods that have proved efficient in the West. Experience has convinced most miners that hydraulicking is not suited to these deposits, owing to the clay and the impurities which they carry and the fineness of the gold. 249 250 EXPLOITING PLACERS The placers which cover wide areas in North Caro- lina have been a source of aggravation to miners, whe have seen others that carry very much less gold worked at a profit. To the uninitiated it would seem that it was merely necessary to turn on the water in order to become wealthy. At the Edith mine in Catawba County nearly every phase of hydraulicking known has been practiced with indifferent success. Owing to a scarcity of surface water it was necessary, in order to mine and sluice the ground, to sink shafts; construct a large retaining dam, to form a settling pond; and finally pump the water from the settling pond back to the mine. To sluice the dirt to the settling pond it was necessary to drive a tunnel and dig ditches. In addition to this work, con- siderable money was expended for boilers, pumps, and water pipes. While there was not sufficient gold recovered by hydraulicking to pay expenses, still there was enough to entice the owner to renewed experiments with the hope of final success. The author believes he was the first to suggest the use of the log washer for such deposits, basing his belief on its fitness from a knowledge of the good work accom- plished in washing phosphate rock, iron and zinc ores. Mr. Overton was the first to put the idea into practice, and originated the washer shown in Fig. 71. The washer is in two units, each having a single log, driven by belts from the same line shaft. Each log is 8 inches in diameter, constructed of steel pipe, rein- forced by wood inside to add stiffness. The paddles LOG WASHERS 251 are arranged spirally as on any log washer, but differ from those usually adopted, being flattened cast-iron blocks weighing 9 pounds each. The logs are geared to run at 300 revolutions per minute, at which speed the blocks act as hammers and break the material. (At the Catawba mine the speed is but 90 revolutions per minute.) The blocks are not intended to break hard rock, but medium hard rock. The troughs in which the logs revolve are semicircular, FIG. 71. made of J-inch boiler plate and supplied with a wooden top that locks to the trough. The first washer is 18 feet long, the second 12 feet long, each being given a rise to the discharge end of about J inch per foot, the object being to form a larger receptacle at the entrance than at the discharge end of the trough. At the dis- charge end of each washer is a spout, b, leading to a rotary screen 2X4 feet; the first screen having f-inch openings, and the second one J-inch openings. Below each screen is a trough. The first trough discharges the 252 EXPLOITING PLACERS material that goes through the meshes of the first screen into the second washer, while the second trough dis- charges the material to the riffles. The material to be washed is delivered through the hopper to the trough, where the coarser part is worked forward by the spiral arrangement of the paddles to the spout, leaving the gold and most of the heavy sand behind. All material leaving the first box flows into the screen, which removes all stones larger than f-inch diameter. The remainder falls through into launder, and flows into the top of the second washer. The stones that did not go through the screen mesh, work out at the end and fall on a short endless belt that conveys them to a long endless belt moving in a direction parallel to the length of the washer. The long belt conveys the stones coming from both screens to the tailing sluice shown in Fig. 72. Each of the four washers at this mine is sup- plied with riffles 75 feet long r,nd about 4 feet wide. The riffles are seen in the illustration to be on each side of the conveyer belt, and all discharge into a common tailing sluice. The riffle floors are of 2 -inch plank, with 2-inch diam- eter holes about i inch deep, bored in them. The holes which are staggered, are charged with a small quantity of mercury. Very little gold is caught in the riffles, the greater quantity being caught in the washers in about the following percentages: First washer, 80 per cent of the gold. Second washer, 18 per cent of the gold. Riffles, 2 per cent of the gold. 253 254 FIG. 73. LOG WASHERS 255 Fig. 73 is an illustration of the Edith mine under the present working conditions, with a dirt bank 116 feet high. The log shanty in the excavation is the pump house of the main water supply, and is located over a shaft. From the bench of earth on which the pump house stands, drill-holes are put down, squibbed with dynamite, and blasted with black powder. The blast shakes the dirt so that when it reaches the loaders FIG. 74. at the bottom of the cut it is in condition for easy shoveling. Twelve men load 400 tons daily into cars. The dirt is hoisted up an incline and dumped automatically into a hopper, that is flushed by a stream of running water. The water carries the dirt to grizzles having 2j-inch spaces. All hard rock which is too large to pass through the bars is thrown out, while the smaller stuff is sluiced to the washers through the sluice box, constructed as 256 EXPLOITING PLACERS shown in the plan, Fig. 74. There are 4 washers at this mine, each capable of washing 100 tons of dirt in 10 hours with 75 gallons of water per minute. It is, there- fore, necessary to make as even a distribution of the material as possible, and this is accomplished as shown. The value of the gold recovered is 60 cents per ton of dirt. The clean-up of the washers takes place once a week. . It is performed by shutting down the mine for half a day and running clean water through the washers until it comes out clean at the riffles. The top is taken from the washers, and the material in them is shoveled into buckets and dumped in the clean-up box. There is a trough leading from the clean-up box supplied with Hungarian riffles containing mercury. The mercury in this trough seems to catch all the free gold, showing that the scrubbing and washing made it susceptible to amalgamation. Figure 75 shows the washing system before it was housed at another plant in North Carolina. Steam Shovel Mining. The problem presented to the Atlin Consolidated Mining Company was the excavat- ing, hoisting, and washing of a 20-foot bank of compact yellow gravel. No natural dump existed for the storage of a large mass of tailings, and stacking and sluicing had to be resorted to. The plant shown in Fig. 76 consists of a steam shovel, a, having a dipper that has a capacity of if cubic yards; 18, 3-cubic-yard capacity side discharge ore cars &, having a 3-foot gauge, to run on a 30-pound rail track; an inclined plane, c, having a 30 slope, and terminating in a platform 45 feet above the bed rock. The cars dump their contents on the platform into chutes STEAM SHOVEL MINING 257 provided with grizzles made of rails. The large material shears off the rails and falls to the stone dump; the small material passes through the bars into the sluice. The sluice is 4 feet each way and 144 feet long, set on a grade of 10 per cent. The first 48 feet are paved with 45- pound rails, placed longitudinally, the remainder of the FIG. 75. sluice with 3 X 3 X J-inch angle iron forming cross riffles. The tail sluice and the extensions are block paved and given a grade. The arrangement of the tail sluices is similar to that shown in Fig. 50, where there is a lack of dumping ground and Y's are constructed. The plant is worked 258 EXPLOITING PLACERS by electricity, as far as hoisting and. haulage are concerned. The shovel, however, is operated by steam, the digging engine having 100 horse-power, while the thrust and swinging engines are 30 horse- power each. The plant successfully handles 1500 cubic yards of gravel per day, and employs from 30 to 40 men. The FIG. 76. water is taken from Pine Creek, which furnishes about 1500 miner's inches for washing purposes, while the elec- tric power is purchased from a nearby power plant. No statistics are furnished in regard to the value of the gravel or the cost of working. However, the Guggenheims are interested in the company, which is a sufficient guarantee that it is not being operated at a loss. Cableway with Self-filling Bucket. In the Alder Gulch of historic fame, a placer deposit was once worked. The German Bar Mining Company, Virginia City, CABLEWAY MINING 259 Montana, believed it was worth reworking, provided they could excavate at low cost and transport the material to a tower of sufficient height to furnish a sluice and a FIG. 77. dump ground. The Lidgerwood Manufacturing Com- pany furnished the plant for them, which consisted of 260 EXPLOITING PLACERS power to run a radial traveling cableway, a pivoted tower and hopper, and a self- filling bucket. The pivot tower, Fig. 77, had a large hopper, a, 40 feet above the ground, into which the bucket, b, dis- charged gravel to a 30-inch sluice, c, set on a 5 per cent grade. The sluice, which was 200 feet long, discharged its fine tailings 25 feet above bed rock, and its coarse tailings near the tower. The pivot tower had a ball-bearing top, d, arranged to turn on its axis, and so allowed a second traveling head tower, a, Fig. 78, to move through an arc of 180. The latter carried the boiler, machinery, tower, and cable anchorage, and traveled on curved tracks. The excavation was made along radial lines, and thus a semicircular pit was worked out around the hopper tower. After each semicircular pit was excavated, the entire plant was moved forward and another pit made. The Knight excavating bucket was developed to dig tough ground by shaving the top, and at the same time crowding right into the material. The bucket is sup- plied with teeth that strike the material as it is dropped by the fall rope. The illustration, Fig. 77, shows it, how- ever, in the position it assumes when loaded. The method of excavating is as follows: The carriage, with bucket hanging teeth downward, is run out on the cable, and the bucket dropped. The bucket strikes the ground teeth first, settles down on its bottom, and, as carriage continues toward the traveling tower with hoist- ing line slack, the bail falls into its natural position, the- back catch automatically locking itself, ready for digging. When the carriage has reached a position much nearer 26l 262 EXPLOITING PLACERS the tower than the bucket, the con veying-drum brake is thrown in, the carriage held stationary on the cable while the hoisting rope is tightened, thus giving to the bucket a : long inclined draft, which enables it to fill. This draft may be varied by simply changing the position o* the carriage with respect to the bucket. The ease in changing the angle of draft is of the ut- most importance in adapting the bucket to the material and depth of cut. The bucket draws into the material, the strain increas- ing until the teeth are buried in the ground, when the leverman releases the conveying brake, allowing the car- riage to gradually slip back to a position over the bucket, thus gradually changing the draft, the bucket meanwhile continuing to dig until the carriage is directly over it, by which time it is filled. It is then hoisted and conveyed to be automatically dumped into the hopper. On level or difficult ground, the long draft, gradually decreasing, is absolutely necessary, and it can only be secured with the endless-rope system. Even in high banks the changing draft is of great value, as the bucket may be hoisted as soon as filled without having to drag it through all the material higher up the slope. The changes are made without stopping the engine, or motion of bucket, and effect a decided saving in time of filling. The fine gravel dumped in the hopper, is washed through the grizzly, m, into the sluice, and thus separated from the large stones. The water comes to the hopper through a 1 2-inch diameter pipe, n, either from a side hill, ditch, or a pump. In this case it was a ditch that furnished a pressure of 40 pounds per square inch. CABLEWAY MINING 263 The bucket had a capacity of i J cubic yards, and 400 buckets have been filled in 10 hours. As soon as the bucket made a channel to bed rock, it was used as a bed-rock sluice through which the top soil and fine material were washed. The water rushing through the cut towards the bucket carried the lighter material to a bed-rock flume having a grade of i per cent, which was not sufficient to move the gold-bearing gravel, and this was excavated by the bucket. The grizzly was made of J X 3j-inch iron bars with 2-inch spaces between them. The boulders that pass over the grizzly stack up on either side of the tower, while the gravel that passes through the chute falls 5 feet to the sluice shown in Fig. 51. The sluice bottom is covered for 24 feet with 16- pound mine rails, the flanges being placed close together. The remainder of the sluice is covered with blocks 4X4 inches and separated crosswise by strips of wood 2 inches high to form the riffles. The labor force for this cable- way consists of 5 men, engineer, fireman, signal man, hopper man, and rigger. There are many placers in the South where cableways could be used to advantage to dig and transport material to log washers. There are other places in the West, particularly Nevada and Ariz- ona, where they could also be used to advantage. In fact, the system of cableways has been developed until its flexibility adapts it to many kinds of placer mining. CHAPTER X. GOLD DREDGING. Dredging has come into prominence within the last 15 years. New Zealand is the original home of the success- ful dredge, where it has been operated since 1886. On the Molyneux River, in New Zealand, there were at one time sixty dredges in operation, and the evolution of the present type was brought about by the experience origi- nating in that country. The river bars gave indications of gold, and being at times rich, it was known that the river bottom must contain gold in paying quantities. The miners of the earlier days could work the shores of the river with spoons, which consisted of a bag laced or riveted around an iron frame and secured at the end of a long pole, so adjusted and weighted that it could be drawn along the bottom. When filled, or partly so, it was hauled up. Boats were next used with this spoon, and an auxiliary boat contained a rocker for separating the gold from the dirt. This dredging was the forerunner of the present bucket system of elevating. "The first primitive vessel took the form of a couple of barrels surmounted by a timber platform, on which the dirt was shovejed by a man standing in the water, the dirt afterward being taken on shore and cradled." ''The next dredge consisted of three canoes lashed together by a board platform and secured by ropes to 264 DREDGING 265 the shore to steady it. It was provided with the spoon already mentioned for excavating. This contrivance was the first pontoon dredge. The next step was to use water-power to work the spoon, and where such power was not available dredging was carried on by spoons being raised by crab- winches worked by hand." Mr. Ward, the inventor of the current spoon-dredge, designed and worked successfully, in 1870, a bucket- and-ladder dredge. The motive power for moving the buckets he obtained from current wheels in the river. This was followed by hand-power, then steam-power, and electricity as practiced at the present time. Dredging is one of the popular ways of recovering gold where the depth of the alluvion does not exceed 60 feet below water level or 20 feet above. The number of dredges at work 10 years ago was about 60; at the pres- ent time there are said to be 500 at work in various parts of the world. The ease with which placer ground can be prospected, and the certainty of cost and recovery, place dredging on a commercial basis almost if not quite as secure as manufacturing. Success or failure in any line of business depends upon experience and watchfulness. To assume that any one kind of dredge is suitable for every kind of ground is a mistake, yet this is done, and failures are recorded. One kind of dredge is better adapted to one kind of ground than another. For instance, where the gravel bed contains few boulders and bed rock is soft, the bucket dredge finds favor; or where the boulders are Urge and the ground tough and cemented, the dipper 266 GOLD DREDGING dredge is to be preferred; again, where the material is loose sand, as in some river beds, the suction pump is preferred. To reduce dredging to a metallurgical proposition some system of sampling tailings to ascertain the loss that is occurring must be adopted. Samples for this purpose should take all the stream part of the time, and the sample so obtained should be concentrated in a rocker, and the gold extracted by mercury. There seems to be a great diversity of opinion in regard to the proper method of saving gold on dredgers. Some operators prefer the sluice box, others prefer tables, and still others a combination of both. The latter method is probably the best, since no arrangements have yet been devised that will save all the gold ; in fact, it is good work to save 70 per cent. Sluice advocates believe in long sluices, although J. P. Hutchins 1 states a case where material that passed through a 120-foot sluice was redredged and passed through a 30-foot sluice, with the result that the short sluice yielded as much as the long sluice, under adverse conditions. There has been very little improvement in the mechanism or construc- tion of dredges, although the cost of working has been somewhat reduced by increasing the capacity. Where two or more dredges are working near each other a central power plant will considerably reduce the cost of the process, by decreasing the cost of handling fuel. No attempts have been made to save the black sands, that often contain values which run from one to ninety ounces per ton of sand, and that sometimes in addition 1 Mineral Industry, 1905. DREDGE IMPROVEMENTS 267 carry silver, platinum metals, and copper. Sands in the Caribou District, British Columbia, carried 64 ounces of platinum per ton of concentrates, worth $1920 at the present price $30 per ounce. It is well known that heavy gold can be caught in sluice riffles, except when it is coated with an oxide of other material. Basing their position on this fact, many dredge operators do not use quicksilver in sluices, con- sequently lose fine and float gold. It is probably for the same reason that gold-saving tables have been dis- carded for sluices. Australian dredgers and Alaskan miners do not use quicksilver, although in the latter country it has been fully demonstrated that quicksilver will recover considerable gold from the tailings. If quicksilver is not needed, there is no fine gold in the placer, a condition of affairs that may be much doubted. An objectionable feature common to all dredges, par- ticularly bucket dredges, is that they cannot clean the bed rock thoroughly. Wherever an attempt is made to clean bed rock by hand, the water must be drained off subsequently to carrying the tailings beyond a point where they will not run back to the place recently excavated. It is probable that in many cases a suction pump could be used to advantage in cleaning bed rock after the bucket and dipper dredges have removed the greater part of the gravel. The principal cause for the recent boom in dredging until it has become the rival of hydraulicking plants in California, is that the returns can be calculated with much certainty. The difficulties in the way of successful recovery by 268 GOLD DREDGING dredging are yet many, not in the commercial sense that dredging will not pay dividends, but in the metallurgical sense of saving a larger percentage of the gold. It has been found that a bucket dredge will recover 70 per cent of the values shown by the drill-holes, and that the recovery of from one to one and one-half grains of gold to the ton will pay expenses, the cost of operating rang- ing from 3 cents to 8.35 cents per cubic yard. The distribution of expenses in dredging operations are about as follows per cubic yard: Hijh. Low. Cost Working 5 Foot Bucyrus Dredge Per Cubic Yard. Oroville. Pay roll . . Power. . . Repairs . . Sundries. . Taxes . . Total . . . 2.05 1.77 3-8o -73 I-I3 1-34 .61 52 Lower. Repairs . Labor . . Expenses . i. 06 to 1.77 Average 1.415 cents 2. 86 to 3. 03 " 2.945 " i. 64 to 2. 05 " 1.845 " 0.64100.73 " 0.685 8-35 3.60 Totals 6.20 to 8.35 " 6.890 " The cost of dredging depends upon the nature of the ground, and, other things being equal, the capacity of the dredge; since fixed charges practically remain the same whether 40,000 or 80,000 cubic yards of dirt are handled monthly. For instance, a 3j-foot bucket dredge mined material for 4.892 cents per cubic yard, while a 5-foot bucket dredge mined the same material for 3.66 cents per cubic yard. In another case a 4-foot bucket dredge in a very hard compact cement gravel could not work for less than 8.7 cents per cubic yard. The dredge is not a useful arrangement in a swift- COST OF DREDGING 269 flowing river, and is best suited to working river banks from the shore inland, in some cases to distances over a mile. Dredges working inland make their own float/way as a usual thing, although they are sometimes greatly assisted by giants or steam shovels that strip the top barren dirt above water level. The construction of a dredge is of considerable im- portance. For instance, in a practically new country where no dredging has been done, exceptional care should be taken to investigate the kind of ground the dredge must handle, and the gold it is to save. Small dredges should be constructed in new districts, and then, if changes are necessary, the next dredge, which will be larger, can be equipped to meet the demands. Dredges cost in proportion to their size and power. For instance, a dredge that will excavate and wash 40,000 cubic yards of dirt per month would cost approximately $40,000, while a dredge capable of handling 60,000 cubic yards of dirt per month would cost $60,000. The increased cost is due to the enlarged hull and heavier machinery needed to handle increased quantities of material in a given time. The above cost refers to bucket dredges. Dipper and suction dredges will cost less than bucket dredges ; and, again, the suction dredge will cost less than the dipper dredge, in fact, a first-class suction dredge can be constructed for $15,000. Mr, R. H. Postelthwaite claimed in 1897 that any ground not deeper than 60 feet below water level, or not more than 20 feet above, and which did not contain rocks heavier than i ton, could be handled at from 3 to 5 cents per cubic yard. 270 GOLD DREDGING Subsequent practice has corroborated his statement, and in one case the cost has been as low as 2.36 cents per cubic yard. The constituent parts of a dredge are: (a) The hull, upon which the machinery floats. (b) The excavator for digging and raising the material. (c) The washing apparatus. (d) The sluices and gold-saving devices. (e) The tailings stacker. (/) The power plant for driving the machinery. The Bucket Dredge. (a) The hull of all dredges must be substantially constructed and designed for the weight of the machinery it is to carry. More than one dredge has sunk because it was not properly calked or designed. The construction of the hull is not a difficult matter and is carried on as for any lighter that carries its load on its deck. The hulls are of wood and vary from 30 to 40 feet in width and from 60 to 120 feet in length. The depth of the hull is usually from 6 to 9 feet, and when com- pleted and weighted with machinery draws from 4 to 6 feet of water according to the size. The frame of the scow is blunt pointed as in Fig. 79 for river dredging; but for inland dredging it may be constructed square at both ends, as there is no current to contend with. The bucket dredge has a well built in the bow that practi- cally divides that in two parts. Fig. 80 is an elevation of the dredge shown in Fig. 79. Its different parts will be described in order as we proceed. Fig. 8 1 is the dredge Indiana, built by the Bucyrus THE BUCKET DREDGE 271 272 GOLD DREDGING FIG. 80. EXCAVATORS FOR DREDGES 273 Company, and is used for the purpose of describing the various essential details that enter into the construc- tion. It is an electrically driven dredge, otherwise boiler stacks would be in evidence as in Fig. 80. The gantry, a, is constructed of heavy timbers, that rise about 20 feet above the main deck. Rolled steel bars, H-shaped, are sometimes substituted for timbers in gantries, although they possess no particular advantages over suitable timber sticks. The bucket ladder, 6, is a substantial steel-trussed arm, that extends some dis- tance ahead of the dredge, the length depending upon the depth to bed rock. It is pivoted to the driving shaft at the upper end, and supported by a bail, c, which is suspended by wire ropes from blocks attached to the cross-tree of the gantry. The ropes are connected with power, so that the ladder may be raised or lowered as found necessary while excavating. At each end of the ladder there are tumbler wheels, whose object is to give motion to the buckets. The upper tumbler is keyed to the shaft which carries the driving wheel, d. Rollers are placed at intervals on the ladder, in order to decrease the friction of loaded buckets, e, as they move upwards to the dump, located on the top deck of the boat. The buckets can dig in deep or shallow water, but must be pitched in each case by the bucket ladder. The tumbler under water is rotated by the bucket chain, which is set in motion by the upper tumbler revolving on its shaft. (b) Excavators for Dredges. There are three kinds of excavators for dredges, the bucket, dipper, and suction pump. 274 BUCKET EXCAVATORS 275 i. The bucket excavator not only digs the dirt, but elevates it to a hopper at the top of the dredge. The bow end of the hull, as previously mentioned, is divided through the center in order to permit the bucket ladder to be raised and lowered, and the elevator buckets to travel. This kind of dredge is not tipped when a load is lifted from the river, consequently the plant is evenly balanced, even though the heavy machinery is placed near the stern. This type originated in New Zealand, and very little if anything has been added to its improve- ment since it was introduced in this country. The movement of the buckets is slow and uniform, the rate of travel being from 1 8 to 20 buckets per minute. The speed should be regulated to deliver the material in a fairly uniform manner, as the feeding is a matter of con- siderable importance. With buckets the material is brought up in comparatively small masses, that permits of it being properly washed without overpowering suit ably designed screens. Buckets are usually made of steel with lips reinforced by manganese steel strips varying in thickness from i to 1} inches. The lips are the weakest part of the bucket dredge, and if they were not reinforced as de- scribed the entire bucket would need replacing from time to time. Considerable wear and tear occurs when working in hard clay containing boulders, as a boulder in such material is not easily removed, and will cut and wear the bucket lip quickly, and often so dent the bucket even when reinforced as to make it practically useless for cutting a bank. To obviate this difficulty it is cus- tomary to drill holes ahead of the dredge working inland 276 GOLD DREDGING and shake the ground with a blast. This will enable the bucket to pick up the boulder or move it one side. Here the Keystone driller again finds employment, in drilling blast-holes ahead of the dredge. The buckets are secured to chains by rivets, and are with the chains made so strong that if they encounter an obstruction that they are unable to move or to glance from, they will stop the machinery. The capacity of the buckets is from 3 to 13 cubic feet; the most usual sizes being 3, 5, and yj feet, and these at a speed of 1 8 buckets per minute will theoretically deliver 120, 200, and 300 cubic yards per hour. Owing to the imperfect filling, the practical delivery will average about two thirds of the above quantities. The Bucyrus buckets are considered more efficient than Risdon buckets, where there are no boulders, and the Risdon buckets are considered to be better where there are many boulders. The only difference between the two consists in their hooking-up and chain construction. The Bucyrus buckets are placed close together, while the Risdon buckets have a bare chain link between them. It is claimed by the Bucyrus people "that Robinson's patent steel chain has advantages over all others, inas- much as the chain pins are protected and lubricated so that sand cannot cut out the links and pins, necessitating their frequent renewal." The depth to which the buckets may work is limited by the power of the engine and length of the bucket ladder, but for deep dredging the boat must be con- structed accordingly. Probably the average depth below water level so far worked by these machines is 40 feet, DIPPER EXCAVATORS 277 although many have been constructed to dredge 60 feet. The buckets deliver their contents into a hopper, so constructed that all material falls into it. No material should be allowed to return directly from the bucket into the water, as there is a probability of its containing gold. A stream of water should be used to clean the buckets at the hopper when digging in clayey or sticky ground. The advantages of the bucket excavator are: It delivers the material to the hopper in a compara- tively uniform manner; It can dig deeper than other excavators with less expenditure of power; It requires but one hull, and all machinery can be placed on that hull. The disadvantages of the bucket excavator are: It cannot raise boulders out of the way, but bangs against them to the detriment of the buckets, without raising material, thereby requiring that the barge be moved ; The buckets are only partially filled, and permit some fine material to run back to bed rock, which they are unable to clean, if hard, and only partially to clean if soft. 2. The Dipper Excavator. The dipper was first adopted for dredging gold in this country. It has been systematically decried, although in some ground it has no equal. The dipper excavator, up to a certain depth, depend- ing upon the length of the dipper arm, is able to move and remove larger boulders than the other excavators. .278 GOLD DREDGING This is made possible by the fork on the end of the dipper, the large mouth of the dipper, and the concen- tration of power. These advantages become more evi- dent when one takes into consideration that they obviate the necessity of raising and lowering the bucket ladder, backing and filling, with consequent cessation of work during that time, and swinging the scow in position. Further, it is possible to excavate more ground in a given .time, closer to bed rock, and on account of the lateral swing of the bucket arm, a wider space without change of the scow's position. The opponents of the dipper usually advance two arguments against its use: First, that the dipper door cannot be made tight without great expense for gaskets and consequently there is apt to be a loss of gold unless they be used. To obviate this loss from leakage, gaskets of common rubber hose are so arranged as not to come in contact with the material during its discharge from the dipper. These gaskets wear well, are not expensive, and can be replaced in ten minutes' time, if necessary, but they are not absolutely water tight. As the material is brought up in masses, with little water in comparison to the bulk of material raised by the other two classes of excavators, the loss of gold from seepage through the door under any circum- stances is slight, and probably not more than occurs from the continual stirring up and sliding back of the ground where buckets do the excavating, and which must necessarily loosen and precipitate some gold. The second objection to the 'dipper is stated to be 279 280 GOLD DREDGING the agitation caused by the dipper's attack on the mate- rial. This attack is no more vicious than that of a bucket in comparison with their sizes, the water in the dipper being pushed out gradually as the material enters; this objection is tenable only where the ground is loose, and the gold is free and very fine; however, in such instances the bucket is likewise objectionable. The specific gravity of gold is such that particles the size of pin heads are not easily floated in swift-running water, and hence the approach of the dipper is not apt to cause the gold to float one side. Mr. P. Wright says "that in the Beechwood district of Australia " he found 95 per cent of the gold within three feet of where it was filled into the sluice, the gold lying on a smooth board, and yet a powerful current failed to move it. Mr. Alex. J. Bowie says that 80 per cent of the gold recovered is found within the first 200 feet of the sluice, and quotes an instance where in a 100 days' run which cleaned up $63,000, 85^ per cent was caught in the first 150 feet. Careful consideration of the imaginary difficulties attending the use of the dipper which are advanced will probably lead to its later adoption, since it has no equal for moderate depths and wide range for handling material. A seriously objectionable feature of the dipper is the intermittent manner in which it brings gravel to the hopper; at times it delivers a full dipper, but more fre- quently a less quantity, with much water. It is difficult to receive material in this way, and generally the dipper will require another scow to treat the material, otherwise DIPPER EXCAVATORS 281 the hopper and sluices must be placed upon the river bank. The same objections apply to the clam-shell bucket in a greater degree, for, should a stone prevent the shells from closing tight, the gold would be lost in getting the material to the hopper; besides, the agitation consequent upon the shutting and lowering of the dipper may be sufficient to float gold away from the material being excavated. These excavators work very satisfactorily in dry placer ground. The dredge shown in Fig. 82 was one of the first constructed in this country, and is, or at least was two years ago, in active operation on the Chestatee River, Georgia. It will be noticed that the dipper is mounted on one barge and the sluice on another. This on first thought is objectionable, but on reflection there does not appear much doubt but that a barge constructed particularly for cleaning the gold furnishes a better opportunity and more space for gold-saving opportunities. Some dredges are constructed so that the bucket arm can be brought back to dump in a bow hopper placed in the center line of the barge but extending over the bow; others have hoppers constructed on the sides near the bow. In case that the hoppers are in the center line of the boat, spuds must be used in the rear; but where the hoppers are placed to one side or on a separate barge, spuds must be used at the rear and on the dumping side. Several dredges of the dipper type are working successfully on the Chestatee River, and the dippers for such dredges vary in capacity from i to 2j cubic yards. The dredge 282 GOLD DREDGING illustrated washes the material through a grizzly by a stream of water into a sluice box, that discharges the tailings in the river. This dredge has considerable black sand to contend with. The dipper dredges at work at Oroville, California, use tailing stackers, and pumps for disposing of the tailings. They also use screens for disintegrating and washing the dirt. According to the Marion Steam Shovel Company, the two dredges in Oroville are among the most successful in that field to-day, although there are many bucket dredges there for comparison. 3. Suction Dredges. A centrifugal pump with a 12- inch suction hose that reaches to the bottom of the river, comprises the excavating arrangement on what are termed suction dredges. The hose is attached to a moving crane on the barge so that it can be moved as desired. Mechanical devices and water jets have been proposed to loosen the material at the suction end. These, however, are not required ordinarily, as the pump will raise sand, gravel, and even rocks approximately the diameter of the hose in size. The most successful dredging plant of this kind was that of Sweetser and Burroughs on the Snake River near Minedoka, Idaho. This plant consisted of a 1 5-inch centrifugal pump, directly connected to an 1 8-inch tur- bine water wheel. The gravel and water together were elevated a height of 25 feet, the suction being 20 feet, and the delivery pipe 5 feet. The material handled ranged from fine sand to 8-inch boulders. While the suction and discharge pipes did not wear rapidly, the CENTRIFUGAL PUMPS 283 pump propeller and casing could not be kept long in repair, and this necessitated frequent stoppages, until a steel lining and a closed impeller were introduced. Even with these improvements the results were not entirely satisfactory. In dredging on the float coal in the Sus- quehanna River near Nanticoke, Pennsylvania, there was very little wear on the pump impeller and casing ; in fact, there was nothing in the way of repairs done to the pump in two seasons, although it handled large quanti- ties of sand, coal, and rounded stones. While the system is cheap as regards first cost, and takes up but little deck-room, it is very difficult to regu- late. At one time the pump will be choked; at another time nothing but water will be delivered; furthermore, a natural selection of sizes takes place. At one time there will be a free flow, but the larger material that moves slowly will gradually form a layer that stops all flow. To keep the Susquehanna dredge up to its work, it required one man with a long pole to keep the material stirred up, and to move the tail pipe from the hole it quickly dug to a new position where the material was within the suction radius. The cost of working gravel on the Minedoka dredge was 2 cents per cubic yard. Its success was due to gravel being washed to the pump, to its working where the tail pipe was practically always in sight, and to its being run by water-power. The quantity of water pumped is always in excess of the material, and the power consumed is out of proportion to the material raised. Centrifugal pumps revolving at high speeds are able to raise large quantities of water a short distance; and 284 GOLD DREDGING within the small radius of their suction, necessarily close to the suction pipe, they have sufficient power to raise mud, fine sand, and gravel. This suction might raise considerable gold, because the velocity of the water entering the suction is greater than the velocity with which gold will fall by gravity through water. The radius of suction is not sufficiently strong on its outer periphery to draw in heavy particles of gold to the central point of suction, while it is sufficiently strong to draw in sand and mud. When the sand and mud are disturbed the heavy particles of gold begin to settle and finally reach the bottom, in which position it is difficult for a suction pipe to dislodge them, particularly if there are boulders on the river bottom, or crevices into which the gold may sink. Suction pumps raise gravel stones without much difficulty, but they cannot raise coarse stones and boulders; and where the bottom rock is covered with these by natural selection, the gold falls in between them and is lost, unless bed rock can be cleaned by hand. As an auxiliary to other dredges where the bed rock is hard and not uneven, they might prove useful in cleaning up gold which the other exca- vators cannot recover. The suction pump as a gold dredger has a very narrow range of usefulness compared with the bucket and dipper. Another drawback to centrifugal pumps is the height to which they can deliver material above the pump. They usually are more successful at the suction than at the delivery end of the pipe line, and it requires excessive power to raise water and material higher than 12 feet. CENTRIFUGAL PUMPS 285 (c) Washing and Screening. Screens on dredges, if grizzlies are neglected, are either of the revolving or the shaking types. i. The revolving screens are of sheet iron with holes ranging from .5 inch in diameter at the receiving end to 5 or 6 inches diameter near the discharge end. At present screens are made from 3 feet to 4.5 feet in diam- eter and from 20 feet to 36 feet long, according to the size of the buckets and capacity of the dredge. The diam- eter of the screens must be such that they will pass stones as large as the buckets will bring up. To prevent excessive wear on screens, it is a better plan to wash all material through grizzlies in the hopper and pass all material over 3 inches in diameter either to the tailings stacker or over the side of the boat. This will permit finer sizing of the material going to the sluices and tables, a matter as important in sluicing as in other kinds of concentration, where close recoveries are made. The length of the screen depends on the kind of gravel to be washed. In every case it should be such that no crowding of the material will occur and prevent it being thoroughly washed. Ground that contains water, rounded stones, and much clay, should be passed through rotary screens, as they are better washers and disin- tegrators than shaking screens. Jets of water, under pressure, issue from pipes inside the screen, if the screen revolves on rollers ; or from the hollow shaft if the screen revolves on a shaft. This water washes the fine material from the stones and through the screen openings. In most cases there is but one screen; but two screens, one inside the other, are better adapted to sizing and 286 ROTARY SCREEN 287 gold saving. The first screen discharges into the sluice, and the second one passes all material to> a tank directly under it. The tank is a distributing box that discharges its contents uniformly over the gold -saving tables. In case there is but one screen, the large stones discarded at the end go to the tailings stacker, while the material passing through the screen openings goes to the sluice, and the fine material to the gold-saving tables. When a single screen is used the size of the openings must be such that no gold will be lost. This is a very uncertain factor, consequently there is need of some large openings, and the necessity of turning some mate- rial into the sluice box. With a double screen the lower screen may be rotated in water and only fine stuff sent to the tables, while the discharge may be delivered to the sluice. Screens should be constructed in sections, in order that a worn part may be replaced without dis- carding the entire screen. The description furnished of a rotary screen arrange- ment is the author's ideal. As now constructed, the material that passes through the screen in most cases passes directly to a sluice box containing riffles and not over a gold-saving table, the supposition being that only coarse gold is in the placer. 2. Shaking Screens. It has been stated that rotary screens are better for clayey material and round stones than shaking screens. Clean gravel with little clay, and material carrying fine gold, are suited to shaking screens. Rough stones are handled with equal facility by either kind of screen. 288 GOLD DREDGING Shaking screens are given sufficient fall and screening area to permit of the gold being thoroughly washed from the rocks before the latter are discharged to the tailings stacker. Fig. 83 shows a shaking screen with gold tables. In the illustration the shaking screen, which has an area of from 600 to 700 square feet, works in the box, a. From a series of openings above the screen, water is projected upon all parts of the screen, washing and disintegrating the material before the finer particles pass into the chute, b, leading to the distributor, c t placed below the screens and above the gold-saving tables, d. The coarse material passes out at the lower end of the screen into a hopper, e, leading to the tailings stacker. The fine material which passes over the tables is carried to sluice boxes, which discharge the material about 20 feet beyond the stern of the dredge. The sluice boxes are also fitted with riffles, and if there is much sand they deliver their material to a centrifugal pump for final distribution. In this case the pump dis- charge pipe is placed on the stacker arm so that the sand is delivered over the top of the gravel (see Fig. 81). Simi- lar arrangements may be necessary with a rotary screen, if gold tables are used in addition to sluice boxes. (d) Gold-saving Arrangements. Before an intelligent conception can be reached of the kind of gold-saving appliances to adopt, the fineness of the gold going to the riffles must be determined. The next important consideration is the material, and the best arrangements to install to wash it thoroughly. As too much water is almost as bad as too little water, experiments should be made to ascertain the minimum quantity of water GOLD-SAVING TABLES 289 required for a maximum recovery. Any neglect of one of these three important items may make the sluice or table riffles but mediocre gold-saving appliances. Hungarian riffles or gold tables such as are shown in FIG. 84. Fig. 84 are used on dredges where coarse material is separated from the fine material before the latter passes over the tables. They require considerable mercury, and are fairly effective when given a grade of about 1 8 inches in 12 feet. They are placed below the sluice- box grizzlies or distribution boxes, and are virtually undercurrents. The grizzlies do not allow anything larger than J inch diameter to go to these tables. The riffles most generally used are of the Hungarian type as previously illustrated, but are supplemented 2QO GOLD DREDGING by the riffle shown in Fig. 85, which is made up as fol- lows: First an iron floor upon which is placed a layer of calico. Above this in the order named is a layer of ordinary cocoa matting, and expanded metal. The metal is fastened in such a manner it can readily be removed when it is desired to wash the cloths. Every few days the expanded metal, which is used to keep the matting FIG. 85. flat and hold it down, is taken up, and the cloths washed in a box to collect the fine gold, after which they are returned to the tables, and the expanded metal fastened in place. These tables are considered the best fine gold- saving devices, and are widely used in consequence. In case there is much black sand, the matting becomes clogged so that the gold cannot settle, and if more water is run over the tables to clean them of sand, the gold goes with the sand. To prevent the accumulation of black sand it must be removed before it reaches the GOLD-SAVING DEVICES 291 matting. Owing to the limited length of sluice boxes on dredges and their narrow width, undercurrents or gold-saving tables are made wide; on some dredges they occupy as much as 1200 square feet of space. There are no better gold-saving devices in existence than are found on dredges, consequently the loss must be due to some extent to imperfect washing arrangements, or to allowing too much material to flow over the table at one time. A steady flow of water is imperative in such work, even should there be an uneven flow of material. If the water passing over the tables contains much alumina or much magnesia, it will slick the tables in a very short time and prevent anything but heavy gold adhering. Recognizing the necessity of thoroughly washing the gold, and at the same time comminuting adhering substances to such an extent that they would be held in suspension by the water, the writer suggested in 1897 that the log washer be adopted on dredges. The success attained by the log washer in the South has verified the author's expectations. In some cases the screens on dredges have been arranged to pass all fine material to centrifugal pumps for additional washing, and these pumps have delivered the washed material to the sluices. There are several objections to this method of washing: First, there is too much water de- livered to the sluices; second, the centrifugal pump is a poor washing contrivance; third, there is an unnecessary waste of power ; fourth, the material is necessarily deliv- ered in an intermittent manner to the pump and to the sluices, consequently more water than is needed must be pumped. Sluice boxes on dredges are about of the 292 GOLD DREDGING same construction as in ordinary sluicing, except that they are often of iron. Where the rotary screen is used without gold-saving tables the sluice boxes are made long, as shown in Fig. 79, and in some instances they extend back to independent barges, that support them in such a way that their length can be materially increased, and an undercurrent placed in the sluice line. (e) The Stacker. There are two kinds of rock stackers in use, both of which are of the endless belt type. The stacker arm is steel trussed, and is raised or lowered as occasion demands by wire ropes that are worked by a small hoisting engine. The ropes are fastened to the bail of the stacker arm and pass through pulleys sus- pended on the cross piece of the stern gantry. At the top and bottom of the stacker arm there are sprocket wheels or belt pulleys; the lower one in most cases is the driver, while the upper one is the driven wheel or pulley. This arrangement is not as economical in the use of power, or as satisfactory, as where the upper pulley wheel is the driver. The rock stacker is par- ticularly useful in ground where there are many stones, and in places as much as 75 per cent of the material is coarse. It also aids in saving gold by keeping stones out of the sluice boxes, and in this way shortening their length. The bucket conveyor on the tailings ladder is said to last longer than the belt conveyor, and to raise material at a higher angle. It requires, however, more power to run, is more expensive in first cost, and less easily repaired, than the belt conveyor. Belt conveyors have carried 500,000 tons of sharp rock without wearing out TAILING STACKER 293 or needing repairs; in fact, they are preferable to chain conveyors where the angle of elevation is not so high as to cause the material to run back, or about 24 degrees. The tailings stacker must be long enough to raise the coarse material to an elevation and to a distance behind the dredge that it will not run back into the diggings. When fine material is to be put out of the way, the pump pipe is attached to the tailings ladder, and the pump must have sufficient power to throw the sand and water over the top of the coarse tailing pile. When the pump is used to dispose of the tailing the tail sluice is not needed, as all material that passes down the sluice box goes to the pump. (/) The Power Plant. Electrical power, when it may be obtained readily and cheaply, is preferred to steam- power. Where two or more dredges are in close prox- imity, it is more economital to locate a steam boiler plant on shore and transmit electricity to the dredges, than to have engines and boilers on the boats. It takes considerable handling to place fuel on board the boat, and it is a well-known fact that several small engines are wasteful of steam to a greater extent than a large auto- matic cut-off engine when generating electricity. There will also be a loss of steam due to condensation, on a dredge, as the engines must be placed at some dis- tance from the boilers. In addition to the disadvantages named, the boiler is in the way on the boat, unless addi- tional length is added for its accommodation. In locali- ties where there are ditch lines, electrical generating plants can be cheaply installed by using nozzles and impulse water wheels. In other localities a small dam 294 GOLD DREDGING and flume can be cheaply constructed to furnish water- power for generating electricity. The power required for a 3 cubic foot bucket dredge is about as follows: For driving the buckets ...... 75 horse-power. To drive a lo-inch centrifugal sluice pump 50 horse-power. The revolving screen requires ... 20 horse-power. To drive an 8-inch centrifugal screen pump 30 horse-power. To move the scow 20 horse- power. Auxiliary pumps, power for tailings stacker, electric light plant, and sluice pump for tailings, would require considerable additional power. In the above estimation, which does not include the power required for a tailings* stacker or sand pump, it will be observed that 80 horse-power or 41 per cent of the power is used for washing purposes, and but 38 per cent for digging purposes. The object in using centrifugal pumps is to obtain a large supply of water, and this is accomplished at the expense of power. The pumps are cheap and easily kept in repair; however, it is probable that by using com- pound centrifugal pumps, the power would be econo- mized particularly in the spraying pumps, where force is desired rather than quantity. A reduction in the quan- tity of water used in sluicing would often be found bene- ficial. The object is to transport the material and not flush the sluice boxes. The following table furnished Mr. D'Arcy Weatherbee DREDGE MACHINERY 295 by D. P. Cameron of the Western Engineering and Construction Company, who are agents for the Bucyrus Company, gives an idea of the weight of a 3j-foot Bucyrus dredge. Name of Part. Total Weight Lbs. Number of Pieces and their Weight. Upper tumbler ... 6,500 Can be cut in 20 pieces, one of which will weigh 1,000 lb., the rest will be below 300 lb. Lower tumbler .... 4>5 Can be cut in 13 pieces, three of which will be about 700 lb., the rest below 300 lb. Digging ladder .... 28,000 Two pieces of 600 lb., the rest about 300 lb. Digging buckets (3$ ft.). 83,000 Bottom about 320 lb., each hood 135 lb., lip 120 lb. Screen, stacker and parts 16,000 Eight pieces would weigh about 600 lb. each, all other parts 350 lb. and less; 70 per cent less than 300 lb. Gearing . , 30,000 Eight parts would weigh about 700 lb. each, the rest from 350 lb. down; 50 per cent less than 300 lb. Engine or motors . . . 15,000 Two pieces about 1,000 lb.; two pieces about 600 lb.; 50 per cent below 350 lb. Boilers 8 soo All below 350 lb. Pumps w 3*** too Winches o wv ^ 42,000 Two pieces 600 lb. All other parts below 350 lb. Other parts 7 600 All below 3^0 lb. Spuds. On the bucket dredge there are two spuds 42 X 1 8 inches X 50 feet long with steel points at the lower end. The spuds, which are raised by machinery and lowered by gravity, serve to move the boat, or hold it steady when dredging. To move the boat forward or backward the spuds are alternately raised and dropped, after the engineer swings the boat by means of cables 296 GOLD DREDGING passing around the front corners of the boat and attached to lateral anchorages. When dredging, one of the spuds rests on the bottom and forms a pivot, around which the boat is swung as the gravel is taken up. The buckets thus take off a segment of dirt about 6 inches deep and 8 feet wide, and after each swing of the dredge around the spud the ladder is lowered 6 inches. The lowering of the ladder continues until bed rock is reached. The bed rock, if yielding, is torn loose and brought up until barren of gold. The dipper dredge is supplied with 4 spuds, one near each corner to prevent the barge from swinging and from tipping. The spuds have racks, and are raised by pinions driven by machinery. The boat is moved forward by ropes attached to anchors and winches. The boom swings 180 degrees; consequently the dipper can dig quite a semicircle, and to a depth depending on the length of the dipper arm, without changing the position of the boat. CHAPTER XI. TRACTION DREDGES: DRY PLACER MINING MACHINES. STEAM shovel excavators have been mentioned under the caption " Exploiting Placers." In that connection, however, there was sufficient water for the excavation, but a lack of dumping ground. Traction dredges are for exploiting placers where little water exists, and where conditions are unfavorable for sluicing, dredging, or the use of other systems of placer mining. To determine whether this method of work would be profitable, exploration and prospecting must be carefully carried on. Sure thing placers do not exist in all localities as they do in Oroville and some other districts, therefore where one test hole was put down in every four or five acres, one and probably more holes will be required for every acre. The land is therefore divided up into sections, and in some cases a Keystone drilling machine takes samples just ahead of the dredger in order to work the richest ground. When communicating with manufacturers of traction dredges the following information in detail is required by them: The lay of the ground; that is, whether it is in a gulch, an old river bed, lake bed, or small valley; The grade of the bed rock if that can be determined, and if not, the slope of the surface; 297 298 TRACTION DREDGES How high the material must be raised in order to obtain sufficient sluice fall; The kind of material to be washed, i.e., whether coarse or fine; The depth from the surface and the thickness of the pay streak; this will furnish practical information regarding the quantity of waste material that must be handled and disposed of; The quantity of water at command and the distance it must be piped; Water in cut, if any, and how deep; A contour map of the ground is very desirable. WB FIG. 86. The end outlines of a traction dredge with plain swinging circle are shown in Fig. 86. The dredge platform rests on two trucks, a, that TRACTION EXCAVATORS 299 have a 27-inch gauge and are moved by the motive power used to drive the other machinery. The dis- tance, WB, from center to center of the tracks is from 12 to 14 feet. The circle, b, is for swinging the boom, c. The length of the boom required depends upon the height of the dump, or HD, above the dredge track, and the distance, CC, from the center of the machine FIG. 87. to the center of the dump. The length of the dipper arm, d, depends upon the depth of the cut and the height, HD. The machinery on the dredge when the dredge is not self-contained consists of an engine for working the boom, a thrust engine, e, on the boom, and a boiler. The capacity of the dredge is governed by the 300 TRACTION DREDGES power of the digging apparatus and the size of the dipper. Self-contained dredges in addition to the machinery mentioned will require power for hoisting the car to the dump, revolving the screen, and working the tailings stacker. Fig. 87 is one of a number of traction dredges con- structed by the Marion Steam Shovel Company. It is a rear view. The skip, a, is loaded on the bank by the shovel, b, and is then hoisted and dumped automati- cally into a hopper. The ore is washed into screen, c, the fine ore going to the sluice, d\ that which passes out of the end of the screen to tailings stacker, e; and the very coarse goes over the side of the dredge. The platform rests on four trucks. The machinery is so arranged that it is not crowded, and comes within the center of gravity of the car platform, thereby doing away with jackspuds and braces, which are necessary when there is but a single track and a narrow platform. The platform sills are of wood or steel girders, stiffened by ties of iron, forming a king or queen truss extending the entire length of the sills. The trucks, platform, and machinery will weigh between 40 and 70 tons. Single-track traction dredges have been constructed to run on a 4-foot 8f-inch standard railroad gauge, in order that all parts might be assembled at the shops and the machines transported to their destination. There is not much gained by this construction, from the fact that it is not often that placers suitable for this method of exploitation are found near railroads; and to lay a WORKING TRACTION DREDGES 301 temporary railroad to the placer ground is expensive, even if the dredge contains its own motive power. Where single-track dredges are used, jack arms and side braces must be adopted in order to keep the machines upright, and prevent the dipper when swinging from straining the parts of the car body. The tracks for traction dredges must be kept as near bed rock as possible, and at the same time the machin- ery should be kept level, to prevent undue wear on the journals as well as keep the water in the boiler in proper position. These machines are said to do work on considerable incline, but they are not built for that purpose, and will save money for the operator if kept level. The trouble with the first machines of this dry- placer type was that they cost as much to keep in repair as the value of the gold saved, and, as they were dis- carded, probably more. Mining with such machines will depend upon the water supply. . Beside a river bank or near some stream they should work satisfactorily, but in situations where water is not abundant they must be economical in its use. If it be necessary, 85 per cent of the water needed for working these machines may be impounded and used over again, thus requiring but 15 per cent of the total quantity to be fresh. The water supply must in all cases be in quantity from 8 to 10 times the amount of dirt excavated. Thus, if one cubic foot of dirt be washed per minute, there will be required from 8 to 10 cubic feet of water needed per minute; of this amount from 6.8 to 8.5 cubic feet may be used over; thus the actual fresh supply 302 TRACTION DREDGES required will be from 1.2 to 1.5 cubic feet per minute. With first-class washers the amount of water required should not be more than 8 cubic feet per minute. The dirt is excavated by an ordinary steam shovel whose dipper is capable of handling hard pan and TRACTION DREDGE WASHERS 303 ordinary hard material, or by the clam shell bucket. The dipper of the shovel works from the arm of a derrick, so arranged in this instance as to have, an arm long enough to deliver the material directly over the hopper, H, Fig. 88. The derrick is mounted on a turn- table which is made to revolve by machinery nearly 140- degrees, or until the dipper is directly over the hopper. The dipper, being required to excavate hard cemented material, must combine strength and power. The boom for the bucket arm is made to conform to the depth of the alluvions. For example, a 35-foot boom will raise material 18 to 20 feet above the track and make a cut 35 feet in width. With the exceptions of the length of arm and the turn, the excavating part of the machine differs very little from the ordinary railroad steam shovel. Where the washing machinery is on trucks at the back or at the side of the shovel, the swing may be halfway round. In some instances the shovel is independent of the washing machine, the latter being stationary and the shovel only advancing. Where the washer is stationary, tram cars or traveling conveyors are used to carry the material from .the shovel to the washer. Dippers of the scoop shape are generally used, although clam shell buckets will answer in some cases. Scoop dippers made to hold ij cubic yards will when filled probably not average over i cubic yard of dirt. They could under favorable conditions make six scoops and deliver six buckets into the hopper in five minutes, or 72 cubic yards per hour; however, at this rate, under ordinary 304 TRACTION DREDGES circumstances, the washer could not handle the material, consequently i cubic yard per minute should be assumed for calculations. Where there is plenty of water the shovels can be increased in size up to 2j cubic yards, but the whole plant must necessarily be enlarged in proportion. Wherever the hopper for the reception of the ex- cavated material projects beyond the side of the car it must be strongly braced; further, the structure is subjected to considerable vibration and strain by the sudden unloading of a cubic yard of material. Another disadvantage is that the hoppers require too much fall for the height of the machine, necessitating the use of power in raising the waste material to the dump and the pulp to the sluices. To avoid the strain from side hoppers, some makers place the washing and elevating apparatus upon separate cars. It is possible by the use of a wide platform and the double truck system mentioned to raise the washing machinery and allow gravity to dispose of the coarse, medium, and fine material without recourse to elevating machinery for that purpose. To accomplish this the washer is constructed on the car platform and the hopper placed for the reception of excavated material above the washer but within the center of gravity of the car. Another system of raising the material to the hopper is where a double inclined track is laid from the ground to the top of the mill. Upon this track two skips run; as the loaded skip ascends, the empty skip descends. The power for raising the loaded skip is derived from TRACTION DREDGE WASHERS 305 the engines which work the excavator. The material having been dumped automatically into the hopper, it is washed down over coarse screen bars. That portion of the material too coarse to pass the bars goes directly to the dump by gravity; that portion which passes the grizzlies falls into the screen, where it is thoroughly washed of fine material, which falls into the sluices, while that portion too coarse for the sluices moves by gravity to the dump. This system disposes of all tailings and pulp by gravity, thus making an economical and power-saving system, by doing away with elevator engines and one pump, as well as the elevating and conveying apparatus. The hoppers in dry placer mining machines should be so arranged that the material may be washed by water from pipes, P, surrounding the hopper, and through iron bars forming the floor of the hopper. This will allow the action of the screen to more thor- oughly disintegrate the material. The coarse stuff remaining on the bars can be removed by mechanism down over a stone chute. The screen should be of two compartments. The inner compartment (being fed by streams of water to further soften and wash the material) should allow the passage of all stuff up to J inch diameter into the outer compartment. This outer screen should be arranged to revolve in water, thus further washing and disintegrating the material. The pulp from the washing hopper is drawn off by a centrifugal pump and raised to the sluices containing the riffles. The coarse stuff from the inner circle of the revolving 306 TRACTION DREDGES screen falls into elevators at B, Fig. 63, and is conveyed by them to the dump. In the illustration, Fig. 89, which is the Traction Dredge of the Bucyrus Company, the hopper is supplied with water from pipe, P, which washes the material down FIG. 89. into the screen; a second hopper, H', receives the washed material containing the gold. The pipe, SP, Fig. 62, is the pipe for discharging the pulp into the sluice box from the pump. F is the A-shaped head frame which supports the bucket ladder, L, over which the loaded tailing buckets travel from the screen dis- charge to the coarse tailing dump. The sluice boxes are not shown. They may be extended a considerable distance from the machine, but if water is scarce the material is discharged where the water may drain into a sump. With plenty of water a one per cent grade will carry off TRACTION DREDGE MACHINERY 307 the material in the sluices, which are provided with riffles. The first few sections of the sluice box should be of light steel, so that they may be readily handled and made water tight. The Chicago Mining Machine has a complicated screening arrangement, and a short riffle sluice on the machine itself. The tailings from the riffle sluice are discharged upon the coarse tailings dump. This com- pany pays particular attention to washing the material in the revolving screen, which has in its inner compart- ment a spiral conveyor. No pitch at all is given to the screen, the material being moved forward by the conveyors. The list of machinery for such dry placer machines comprises a boiler of the upright or locomotive type, engines to work the shovel and derrick, engines to run the washer and conveying machinery, pumps to supply the water to the washer and sluices. The horse-power necessary to work the shovel is fur- nished by a double 8 X lo-inch engine, and may be rated at 25 H.P. To run the elevating and washing machinery 6 X 6-inch double engines are used, which may be rated at 10 H.P. Centrifugal pumps are used, and they will require 15 H.P. each for their independent engines. At times an auxiliary steam pump may be required, and in some instances it is part of the system to use it for pumping water to the hopper and washer, leaving the centrifugal pump to work the pulp only. The screens, elevators, sprockets, chains, rollers, etc., will vary in style and make, according to the machine manufacturers' patterns, and are therefore not described. 308 TRACTION DREDGES With traction dredges whose rated capacity is i cubic yard per minute, it is safe to estimate that in one hour out of every ten the machine must be stopped for repairs, or for advancing, or other cause, which will place the average duty at 500 cubic yards per day. The fuel will generally be wood, at $4.50 per cord, and two cords daily, or $9, for 50-H.P. engines. Wear and tear, oil and waste, will amount to 3 cents per yard, or $15 per day. The labor of 5 men, averaging $3 per day each, $15, making the total expenses of running such a plant, not including quicksilver lost, $40, or 8 cents per cubic yard. This estimate of running expenses does not include the superintendent and his expenses, or the transporta- tion of the gold dust. The latter two items will amount to $10 daily at least, bringing the cost to 10 cents per cubic yard. The amount of gold collected will depend upon the machine construction and the superintendent; a poor machine will not aid a good superintendent. Suppose a machine weighs 50 tons, or 100,000 pounds; the cost at the mine will approximate 7 cents per pound, unless some patents in connection with it raise it considerably higher. Suppose the value of the gravel is 20 cents per cubic yard, and 90 per cent of the value is recovered. The profit under the conditions cited would be $5000 the first year if the entire year could be worked through. There is no doubt but that traction dredges are better calculated for some conditions than other methods of washing gold, and that they have not received more general attention is due to the exploitation of floating DRY PLACER EXPLOITATION 309 dredges, and the unwillingness of operators in this line to experiment with anything new. What has been said previously regarding the thorough exploration of placer deposits applies here. The loca- tion of the deposit with reference to the nearest railroad station, and the condition of the roads leading to it for transporting machinery, are matters of importance. In case it is impossible to transport the boiler, power may possibly be transmitted by electric wires from a distance. Several reliable steam shovel concerns furnish the machinery and plans for traction dredges. These com- panies are not willing to build machines for placer work unless they are assured beforehand, by examination and thorough exploration of their own or some other reliable engineer, that the diggings are of sufficient value to make the enterprise a success. The Bucyrus and Marion Steam Shovel companies state this. From the very nature of placer mines that is, the cemented state of the gravel it follows that if the material can be broken up before it reaches the sluices or the dipper the chances for gold recovery are improved. There are many instances where the ground is so tena- cious or the banks so high that it is thought advisable to run in tunnels and counters to break it up with powder. Experience in breaking down gravel banks with pow- der will satisfy most people that small blasts on the edges of a bank are more economical in the use of powder and more effectual in breaking material fine than large blasts in tunnels. For shovel work, a blast which merely jars the surface and does not throw out the 310 ' TRACTION DREDGES material will afford easy working for the dipper, and, what is more essential, will permit the ground to be washed much easier. The effect of the shot seems to be that of rending the whole mass of dirt without displacement, hence it is very advantageous where water is scarce and steam shovels are used. If the dipper delivers large lumps of cemented gravel of a tenacious character to the hopper, considerable water must be used to wash it down so fine that it will disintegrate readily; but water in such cases is an item, and consequently any method which will bring the material to the hopper in such shape as to reduce the quantity of water to a minimum will help the washing and recovery that much, and further increase the capacity of the machine. Small blasts are considered to require more powder than large blasts in comparison with the proportion of the ground they disturb. This is true to a certain extent, but it must be borne in mind that the ground is more thoroughly rended by small blasts than by large ones, and it is the results in detail which are sought; in other words, the quality rather than the quantity for traction dredges. Dry Placer Machines are those constructed to work without water, consequently they cannot be as effectual as machines using water. There are many placers in Nevada, Arizona, New Mexico, and Lower California, where water is lacking, and in such placers all kinds of schemes have been exploited ; and it may be set down as an axiom that all dry placer machines will prove failures, unless gold is so plentiful it may be sifted from the dirt, and under the latter conditions a jo-mesh sieve WORKING DRY PLACERS 311 would suffice. There are cases on record where mate- rial is pulverized to some extent and tossed. When thrown up the wind blows the lighter material away, while the heavier material is caught on a sheet. This is again tossed until the heavier particles are concen- trated to small bulk and the gold picked out, or the con- centrates carried to a place where water can be obtained. pifc f w^- JH| I '! -: FIG. 90. The Allis-Chalmers Company exploit the Wood dry placer machine, but the writer not being particularly interested in that kind of mining has never inquired into its virtues or where it has been successfully used, unless the machine illustrated in Fig. 90, a description 312 TRACTION DREDGES of which is kindly furnished us by George W. Parker, represents that machine. In the Engineering and Mining Journal, 1 1903, a description of the Edison and Freid dry concentrators may be found. Both machines depend upon gravity and an air current to separate the lighter material from the gold. The process is to size the material and send the sizes to separators adjusted to the size. Dry washing is carried on at the Sunnyside mine near Round Mountain, Nevada. An idea of the work performed can be derived from Fig. 64. The few large rocks are picked out by hand and the gravel thrown by shovels against a i-inch sand screen. The screened material is shoveled into the dry washers. The dry washer consists of a screen with J- inch openings, from which the oversize is delivered by a piece of sheet iron 2 feet beyond the end of the machine. The undersize returns to the head end, where it is fed on a frame covered with a coarse heavy cloth, across which are riffles about 4 inches apart. The frame with riffles is shown in the foreground to the right, and the washer is directly back of the man cleaning the riffles. The frame when in place forms the upper side of a bellows that is turned by a crank having a flywheel. The puffs of air through the cloth agitate the gravel, and, aided by the slope of the frame, it is discharged at the lower end, while the heavier gold is retained in the riffles. The gravel and gold retained by the riffles are brushed off into a tub, and after a sufficient quantity 1 Mr. George W. Packard, Mining Engineer, Boston, Massachusetts. DRY WASHING 313 of this concentrate has accumulated, it is put over the machine a second time. The tailing from this second concentration contains gold and is sacked for shipment. The concentrate from the second operation is washed in an ordinary gold pan, and the black iron sands and gold separated by a magnet. Two machines working loj hours per day, handle 35 tons of dirt. It requires 20 men to dig this amount of dirt, screen and put it through the dry washers. ,/.. " ' ... K v "!.->' ','. ' , <> 1 1 '- :.''. < :'. !.'''' .:.' ' I .. '' '' ' CHAPTER XH. BLACK SANDS. NEARLY eve.ry placer deposit contains more or less magnetite, meccanite, or ilmenite, and at times other heavy minerals such as garnets, platinum, and the platinum metals, monozite, etc. The origin of the sands is not difficult to fathom, for some of them are found in the tailings from stamp mills, which indicates that they were originally associated with other minerals in rock formations. Minerals of this description are not easily oxidized, and in some cases are not affected by weak mineral solutions, or acids. Black sands in some cases are so abundant, that they interfere with sluicing operations, particularly in some river opera- tions. In most instances they carry gold, which varies from J to 90 ounces per ton of clean sands. The latter quantity is not usual, however, but as high as 4 ounces per ton is not unusual. The Minister of Mines of British Columbia publishes in his 1904 Report the value of some of the black sands in one sample at least from the Caribou District. The assay value was as follows: Gold, 95 ozs. per ton. Value $1900 per ton. .Silver, 180 " " " " 90 " " Platinum, 64 " " " " 832 " " 314 PLACER SANDS 315 Palladium, 61.4 ozs. per ton. Value $1769 per ton Osmiridium, 42 " " " " 1386 " " The remarkable feature about this deposit is that the quantity of silver is far in excess of the amount usually found with placer gold; further, that the assay reflected some copper which was probably alloyed with the silver, although it may have been alloyed with the platinum. The quantity of iron in the sample was neglected; however, all indications point to the iron sands having an attraction for gold when in solutions. The nature of the gold shows it to be in a very thin film about the oxides, as if placed there by solutions, and only sol- vents can separate the two. Cyanide solutions are quite effective in obtaining gold from black sands. It will be found that the black sands on seashores are not as rich in gold as the fresh water sands of inland placers. While there is no question in regard to the value of some black sands in placers, there is great uncertainty as to their quantity. This uncertainty in placer mining is sometimes the cause of cocoa matting tables becoming quickly filled, but this would suggest a means whereby they could be accumulated as a by-product. Mr. John M. Nicol 1 writes interestingly on this subject, and we have therefore taken the liberty of inserting some of his ideas, which are pointed. "Unfortunately for the interest of abstract science, 1 Mining and Scientific Press, Jan. 19, 1907. 3i6 BLACK SANDS many other workers, like myself, are no doubt engineers employed by large firms, who cannot, in justice to them- selves or their employees, reveal all the knowledge that they acquire. There are, however, a number of points of general interest open to discussion by all parties, and I take pleasure in calling attention to some of them. " There is no new discovery about ' black sands. J They are to be found disseminated throughout the sand and gravel both ancient and modern of practically all river, lake, and sea- beach deposits. The various min- erals are associated together by virtue of the fact that they are all of high specific gravity, and also, that owing to their durable structure, Nature has had the oppor- tunity of concentrating them in the river channels from a vast area of country from which they were originally eroded, and the nature of the minerals composing the grains will therefore largely depend upon the geological features of this area. The grains are of all sizes, from a maximum of about J in. diameter down to material that will pass through a 2OO-mesh screen or even finer. " The whole question is simply one of ordinary placer mining, with some definite system worked out for saving a larger percentage of fine gold and also of saving all of the other by-products that have hitherto been allowed to run to waste, and of doing this on a strictly commercial basis, without undue capital expenditure and at such low cost of operation that a sufficient profit will result to repay capital, interest, and a good surplus besides, before the deposit is exhausted. " Wild statements have been made regarding the value BLACK SAND POSSIBILITIES 317 of black sands, and samples have been submitted which assayed $i,coo per ton, but it must be remembered that these samples consisted of a few pounds actual weight containing a few dollars actual value, that had been con- centrated down from possibly many hundred cubic yards of gravel, and that before one ton could be obtained probably 4,000 to 5,000 tons of gravel had to be washed down, so that the real value of the original deposit in place possibly did not exceed 20 cents per ton. The first thing to be done, therefore, is to base all reports on the value per original ton or cubic yard of gravel in place, from which the black sand concentrate has been obtained. " In river deposits, the possible flood line is of great importance. Possible hydro-electric power sites in the neighborhood should also be noted, as there are many modern methods applicable, that were not within reach of the early placer miners, where electric power can be obtained conveniently for pumping, elevating, and con- veying, and for driving the necessary machinery for any plant that may be installed. " The ground should be thoroughly tested either by drilling or by shafts; if the seepage is not excessive, the latter is preferable. In case of an elevator proposition, the proportion of fine to coarse gravel must be carefully noted as follows : " The proportion by volume per cubic yard of all gravel below 2 inches, from 2 to 5 inches and from 5 to 12 inches. Gravel over 12 inches must be considered as too large either for practical dredging or for hydraulic elevating. " If conditions permit, the whole of the gravel -extracted 3i8 BLACK SANDS should be washed, and the coarse gravel stacked on one side. This may be conveniently done by means of a washing platform discharging by a short sluice into two or more pairs of rockers, which may alternately be cleaned up at short intervals. No riffles should be put in the sluice, nor quicksilver used. The clean-up of the rocker riffles must be passed through a lo-mesh screen, the undersize going directly to a settling vat for further test treatment, and the oversize being roughly picked over and thrown to waste. Any coarse nuggets or gold that may be caught on the rocker grizzlies or on the washing platform should be kept separate and their individual weights and measurements recorded. " That which is saved in the riffles of the rocker may be considered as material that could be saved by ordinary sluice-box methods and that could certainly be saved by sizing and concentrating on the tables. The tailing from the rockers must also be weighed and passed through a lo-mesh screen. The oversize should be roughly picked over and then thrown to waste, and the under- size 'panned down' by panning back and forth between two miner's pans. If skill and care are exercised, practically all of the black sand that has escaped the rockers can be saved by this method. All of the concen- trate caught by this means, will have to be tested as mentioned below. " The gravels of different mines vary so greatly, as do also the proportions of the different associated minerals and the size of the grains, that it is more than probable that each particular plant will have to be designed with regard to the local conditions. I think, however, it DRYING SANDS 319 will be generally conceded, that all gold and platinum grains above f inch diameter are comparatively easy to save. The real question is how to save the fine, and especially how to separate as well as save the associated by-products, without destroying one to save the other. The following additional tests are therefore necessary, and will aid in throwing some light on a possible solu- tion of this problem. "The material saved from the settling vat of the rockers, and from the pan concentrate, should be carefully dried in sheet-iron trays over a roughly constructed furnace. For small tests, the miner's, gold pan may be used for this purpose. Care should be taken to make certain that the settling vats are thoroughly clean, and also that the trays are carefully dusted after the product has been dried, as otherwise some of the fine gold is liable to be lost. The dried product should now be weighed in bulk and a record made of its actual weight in pounds and of its proportionate weight per cubic yard of gravel from which the concentrate was extracted. For small hand tests, it is most convenient to give the weight in grams, and for the large tests in pounds, though if the facilities exist, it is far best to use the metric system right through. Unfortunately most miners do not understand the metric system, and a report to be intelligible to them, must be given in cents per cubic yard, and the weights in pounds. " The dry product should now be passed through a series of ordinary laboratory sieves from 10 down to 100 mesh or even finer. Each oversize will be carefully separated and weighed in bulk, the magnetizable prod- 320 BLACK SANDS uct will be removed and weighed, and the residue can then be conveniently treated by the old-time method of blowing, care being taken to blow the tailing on a large sheet of paper, so that it can be collected for further treatment. The gold particles remaining in the small blower must then be weighed on a button balance and placed in a small vial properly labeled for future refer- ence. An assay sample should be taken from the origi- nal pan concentrate and also from the magnetizable product and the residue after the gold grains have been removed, and assays made and recorded. This process may be carried on for the oversize of all the different screens, and the final undersize, which passes the finest screen, used. The results of these tests may then be tabulated. "As the result of these tests, it will now be possible to form some idea as to where the values exist, that is, so far as the gold is concerned, but it will be found to be exceedingly difficult to remove the gold from the plat- inum, except, by resorting to the usual refinery methods. The residue remaining after removing the magnetizable product, will consist of other by-products, some of which may have a commercial value, together with a certain amount of fine gold, and just here is where the great field for research is open; for at the present moment, I do not i know any process by which these different products may be separated and put into marketable forrnv ** " Care must also be exercised in making a magnetic separation of the magnetizable particles, for if too strong a magnet is used and swept hurriedly through a large MAGNETIC SEPARATION 321 mass of sand, the clusters of iron grains will almost always pick up and hold in suspension a certain number of gold particles. For laboratory purposes, I have found it most convenient to use an ordinary 5 or 6-inch horse- shoe magnet and to cover the poles with a fine cambric bag. I then spread out the sand to the thickness of rV inch on a piece of paper, and gently pass the covered magnet back and forth over the surface, and the mag- netizable grains will cluster on the outside of the bag. The covered magnet with its adhering particles is then placed in a glass bowl and the magnet withdrawn from the bag and the latter shaken. This operation should be repeated until all the magnetizable product has been separated from the sample. The product collected should again be spread out on a piece of cardboard and gone over a second time with the magnet; this .time, however, the bag must be drawn tightly over the poles of the magnet, and the latter must be tapped gently while picking up the grains, so that any non-magnetizable gold or platinum particle will be freed from the clusters and fall back on the cardboard by virtue of its specific gravity. The use of a bag as described above will be found to facilitate the operation, and is much quicker than placing the bare poles of the magnet against the black sand. " The gold that has been separated should be carefully examined under a glass, and notes made regarding its surface appearance. It will also be a good plan to make an amalgamation test and find out by weighing what proportion of the gold will or will not readily amalgamate. 322 BLACK SANDS "As a result of these tests, we now have the following data: " i. The weight of fine products resulting per cubic yard of gravel that will have to be treated by concentra- tion, and we can now, therefore, estimate upon the necessary table area per cubic yard of gravel to be washed. "2. The weight of black sand concentrated per cubic yard and the approximate gross value per ton of con- centrate, and also per cubic yard of gravel. "3. The proportion by weight of separation that can be made by magnetic methods. " 4. The values, if any, that are in direct association with the iron grains and would be lost by this method. Gold and platinum assays should be made. " 5. The values that remain in the non-magnetic resi- due subsequent to wind separation of the clean gold, and that with our present knowledge can only be saved by smelting. " 6. The value of the clean gold that has been caught by the three processes. "7. The proportion of gold that will amalgamate, and if the non-amalgamating gold is coarse or fine. "8. The quantity of residue containing the by-products that need further treatment. " In the foregoing, I have merely outlined some of the most important tests, though numerous others will no doubt be made before a final solution of the problem can be arrived at. We may, however, now commence to formulate some definite arrangement for a plant to treat the black sand and to indicate the nature of the SCREENING SANDS 323 problems most likely to be encountered. Broadly speaking, all of the coarse material of a placer is value- less, and therefore the sooner it is dumped and gotten rid of, the better. All coarse gold above J-inch size is easy to catch, and an arrangement of a few riffles in a short line of sluices will take care of that feature. Hence the first and most important step is to size the material, say to J inch, and reject the coarse after passing through a sluice. It will be equally necessary to get rid of the excessive quantity of clay and fine product, which might impede the successful operation of further con- centration. "As dump is an important consideration in many placer mines, it will be necessary to design a plant with as little loss of head room as possible, and I would suggest the following arrangement: At the discharge end of a sluice, where the material is received from mining operations, a grizzly should be placed, having a suffi- cient area to pass all of the fine material and practically all of the water. It should be placed at such an angle that the coarse material will roll off to dump. The grizzly should be provided with taper bars and spaced about i 7 * inch. All of the fine material will pass by a large sluice to a distributing and hydraulic classifier, which will get rid of the excess water and very light sand and clay held in suspension. "As a certain amount of float gold might be carried away to the reject, I would suggest that this be passed through some form of amalgamating device, the Pierce amalgamator being a good machine for this purpose, and as the light gold has probably a clean surface, it 324 BLACK SANDS will be fairly easy to amalgamate. It will, however, be advisable to make a number of tests by means of set- tling vats, to find out whether the value of the gold and by-products saved will be worth the capital outlay necessary to save them. " The heavy sand from the hydraulic classifiers will pass to some form of classifying sieves, designed to handle a large bulk at a minimum of capital and current ex- penditure. These should size from T 5 ^ to, say, J inch, and must be of simple and durable structure, or the placer miner will never bother with them. " To size all of the material from a placer mine, to reduce the product to be treated to a minimum bulk, economically and without loss, and to deliver it in a form suitable for further concentration and treatment, is a matter that offers a broad field for intelligent design and invention. The quantity and proportion of this sized product to the original gravel will vary according to the nature of the gravel mined; and judging from my experience, it will be least in modern river channels, and greatest in deep, ; ancient deposits, and may vary from 20 to 60 per cent of the original deposit. " Some form of concentration must now be adopted to treat the fine material, and although cocoa matting tables with expanded metal riffles have been used fairly successfully for the purpose, they are to be condemned because they are not continuous in operation; and all forms of non-continuous concentration are bad, owing to the fact that the surfaces choke and the values com- mence to slide over and are lost. This is prevented by frequent clean-ups, but this entails too-great an outlay TREATMENT OF SANDS 325 for current expenses, and quickly reduces profits when treating such a low grade product as the sand of placers. "The Finder concentrator is a good machine for this purpose. Its capacity is about 40 tons per day, equiva- lent to handling the product from 60 to 100 cubic yards of gravel. It is also capable of delivering three grades of concentrates and tailing. Any form of concentrator could be adopted, according to the ideas of the mine owner. "The suggestion is made to the miner to either ship his product to a smelter, or hire a skilled metallurgist. If he desires to be his own metallurgist, proceed as fol- lows: Treat with diluted nitric acid; wash; amalgamate without grinding, to remove the free gold; wash residue through a fine steel-wire sieve. If platinum is present, this can be dissolved by acids, using about 15 times its weight of aqua regia, and precipitate by sal ammoniac. The precipitate of platm-ammonium chloride can be dried and treated by the usual refining methods." Dr. David Day of the United States Geological Sur- vey had charge of an experimental station at the Lewis and Clark -Exposition, the object of which was to con- centrate black sands, and extract therefrom the valu- able minerals. The method he followed was about as follows: First the sand was dried, and the magnetic minerals separated by magnetic concentration; the sands were then converted into pig iron and steel by the elec- tric furnace. The tailing .contained the gold that was not lost by magnetic concentration, platinum and other non-mag- netic sands. 326 BLACK SANDS From a commercial standpoint the process was not a success, although it was talked about freely, and some unskilled in mining presumed it was a wonder- ful discovery of science. To spend $5 to recover $i is not a scientific discovery, and the whole affair was the cause of much amusement to mining engineers and metallurgists. On this subject .the Chicago Inter-Ocean said: Dr. Day has demonstrated to the people of the Pacific coast that values of untold billions of dollars are to be found in the black sands which line almost the whole Pacific coast and form the banks and river bottoms of almost every river flowing into the Pacific Ocean, from Alaska to Southern California. That these black sands contain a large percentage of iron has been known for many years. In fact, it has been estimated that, if the iron could be separated from the sand and smelted, the Pacific coast could supply sufficient iron for the markets of the world for thousands of years, but as yet no practical method has been discovered for separating the iron in commercial quantities from the sand. Machines have been made which will separate the iron from the sand in small quantities when the sand has been thoroughly dried, but the capacity of these machines is so limited, and the cost of drying the sand is so great, as to render them commercially value- less for treating the black sands. STOREHOUSE OF RARE MINERALS. But Dr. Day demonstrated at the exposition at Portland that the black sand of the Pacific coast contains many other valuable minerals. Professor Richards, of the Boston School of Technology; Professor Kemp, of Columbia College; J. F. Batchelder, chairman of the mining committee of the Portland Board of Trade; and an able corps of assistants from the various schools of technology, all DR. DAY'S EXPERIMENTS 327 under the supervision of Dr. Day, carried on an exhaustive analysis of the black sands, from samples taken from thousands of loca- tions along the beaches of the Pacific coast, the beds and bars of rivers flowing into the Pacific Ocean, as well as from the dry beds of ancient rivers in the interior of the Western country. The preliminary reports of Dr. Day's investigations have already been published by the government at Washington, and the publi- cation of his complete report is eagerly looked for by the people of the Pacific coast. While it was known that the black sands contained free gold in varying quantities, yet it was considered impossible to .recover this gold, on account of its being mixed with the heavy grains of iron, and no practical way of freeing it from the iron being known. How- ever, the government reports of Dr. Day's experiments show that, after he dried the black sand and extracted the iron, by using one of the machines already referred to, it was possible to recover the free gold in paying quantities. GOLD FROM THE IRON. But this is not all. The reports show that nearly all the iron in the black sands carries "rusty" gold and that, by separating the iron grains from the sand and treating the iron itself, values in gold were obtained running from $6 to $600 per ton of iron extracted. Furthermore, by placing the sand (from which the heavy iron had been extracted) on the gently oscillating tables, where the separa- tion of the sand into its component parts was made by gravity by pouring water over the incline, it was discovered that the sand contained, besides gold, large quantities of other valuable minerals which were easily separated, such as monazite chromite, garnet, zircon, etc. (some of them worth over $400 per ton, and platinum, which is more valuable even than gold. As if these discoveries of untold values were not sufficient to set the mining world of the West on fire with excitement and antici- pation, Dr. Day, after demonstrating that many of the sands tested contained as high as 600 pounds of iron to the ton, erected a ten- 328 BLACK SANDS ton electric furnace, and in one shdrt hour, by adding lime and broken coal to the iron, which had been separated from the black sands, smelted the iron into high grade steel, which has stood all tests for purity and toughness, and shown that the black sands of the Pacif.c coast will stand alongside Norwegian and Swedish iron ore as the mother of steel. $100,000,000 IN IRON. The discovery has created even greater interest than the fact that the sands contain gold and platinum and other precious miner- als, for the Pacific coast States and Territories always have depended on the East for their supplies of steel and iron. The steel business of the Pacific coast amounts to more than $100,006,000 per year, and oh every tdn of iron or steel used on the Pacific coast, a cost of $16 ]fef toft has to be added for freight charges, the freight being regulated^D/the rates^by water; fdr so' difficult is it to get sufficient iron to the Pacific coast to supply its rapidly increasing demand for the material, that thousands upon thousands of tons of iron and steel are b roughti around tyy Cape Horn by boat from Glasgow, Scotland. This is taking coals to Newcastle with a vengeance, ^foEiin) almost every foot of sand lapped by the waters of the Pacific jQce,an^ along the shores of the States of the West, is found the pre- idous iron which the people of the West now go thousands of miles from home to purchase. .'.:,..;..> j , The questions of interest. that naturally arise are: ... i. How did these minerals get into the sand? > i , . ,.*' 2. How extensive are the sand beds? ; .: 3. What percentage of iron does the sand contain per ton ? i. . 4. How are the iron and minerals to be extracted in commercial quantities? CONTAINS INCONCEIVABLE WEALTH. Dr. Day's investigations, for which special purpose the last Con- gress made a liberal appropriation, show that the black sand is found in: enormous, unlimited deposits along the ocean beaches BLACK SAND FORMATION 329 of the Pacific States, but particularly along the coast of Oregon. In some cases the sands of these beaches have been found to con- tain as high as 40 per cent of iron. But the greatest values per ton of sand are found in the beds of the rivers flowing into the ocean, for, while they contain less iron (in some cases as low as 10 per cent), still their values run higher in gold and other precious minerals, for these sands are formed by erosion and the breaking down of eruptive rocks which contain minerals and metals of most diverse kind and value in their structure. The dissolution of these mineral rocks along the course of the various rivers for ages past and the erosion caused by these rivers, which have been cutting channels through these rocks for probably hundreds of thousands of years, have separated the rocks into their component parts, forming the black sand, and the rivers, even now, are ceaselessly carrying this precious sand down their entire course and dumping it into the Pacific Ocean, where, by dif- ferent currents, it is returned to the mainland to build up the black sand beaches of the Pacific coast. ERODED ROCK RELEASES GOLD. The pieces of eroded rock from constant friction one upon the other, during their course down the river, gradually grow smaller and smaller as they are moved farther down the liver by its currents, gradually dropping their burden of precious minerals, until, on reaching the ocean, the sand contains more iron than anything else, while the higher values in gold have been left farther up the river, where they are found in such large quantities, unmingled with a high percentage of iron, that placer dredging has become an established, lucrative business pursuit. The black sand has always been known as the "thief" of the placer miner, for sand or gravel that runs higher than 2 per cent in iron cannot be worked profitably by methods now in vogue, for the grains of iron, being nearly as heavy as gold, fill up the riffles and make the separation of gold impossible. In fact, many of the most valuable placer mines are idle to-day on account of the black 330 BLACK SANDS sand thief, which the United States Government now tells us con- tains, in itself, more wealth than human mind can conceive. Summing up we find 1. That the aggregate amount of magnetic iron contained in the black sands of the Pacific slope is beyond calculation and prac- tically inexhaustible, as the deposits are being constantly added to by natural accretion. 2. That, in order to utilize this iron commercially, it must first be magnetically separated from the sand, without drying, as the cost of drying a ton of sand for the purpose of recovering 40 to 400 pounds of iron is much greater than the commercial value of the product warrants. 3. That, with the iron extracted, the high class minerals, such as gold, platinum, monazite, zircon, etc., which are almost uni- versally found in these sands, can be easily and cheaply separated from the surrounding "gangue" by methods of concentration now in general practical use. 4. That the magnetic iron itself almost always contains sufficient "rusty" gold to yield a handsome profit by lixiviation, although, as a rule, not enough to pay for treatment by any other process now known. 5. That the magnetic iron when separated from the sand can be reduced in an electric smelter to commercial iron or steel, ready to supply the Pacific coast markets. 6. That the steel so produced, smelted with cheap electricity generated from water power, need not exceed $12 per ton, while the present cost of pig iron on the Pacific coast is over $27 per ton a saving of $15 per ton over present prices of pig iron alone. The government has pointed the way to fabulous fortunes and gigantic commercial enterprises through the black sands. It now remains to be seen if scientific discovery and further experiment will lead the way to the practical, profitable, commercial uses of the limitless black sand beds of our Western empire. That this article tells the situation exactly, is evident from the following copy of a letter written by Dr. Day LOVETT CONCENTRATOR 331 himself to the manager of the Inter-Ocean Newspaper Company. DEPARTMENT OF THE INTERIOR: UNITED STATES GEOLOGICAL SURVEY. PORTLAND, ORE., February 21, 1906. Mr. Samuel S. Sherman, Business Manager, The Inter-Ocean, Chicago, III. DEAR MR. SHERMAN: I thank you very much for your very com- plimentary article of January 21, which requires but little in order to make it perfect. I will be glad to give you further reports on the black sand work. Congress has just extended the work, and it will start again in a few days. The black sand subject is really one of very great interest and is going to aid very much good citizenship on the Pacific coast, for it is not a matter of speculation but simply of untiring industry, with all the personal improvements of character which come by that kind of work as contrasted with the usual speculation so frequent in the mining industry. Yours very truly, DAVID T. DAY. The only concentrator we know of in the United States that will treat the black sands wet is shown in Fig. 91. This machine, which is not large, handles dry material readily, to my satisfaction; and Mr. J. F. Batchelder, who was employed by the Government in its investigation of black sands, considers that it preempts the whole field opened by the Government's investigations at Portland. The Lovett system consists in raising black sand from a river bottom by means of a pneumatic device or other means. The material so raised is screened, and the fine 33 2 BLACE. SANDS material carried to a sluice box in which is placed a Lovett magnetic separator. The tailing is passed to mercury plates. The claim is then made that " this process of FIG. 91. recovering free gold is protected by United States patent, which covers the use of any solvent after magnetic sepa- ration." The writer ten years ago made experiments on concentrates with cyanide solutions, the concentrates having been extracted from a mass of sand by means of a magnet. We therefore think this claim somewhat broad, and the writer believes that Professor Christy also made experiments of this kind in the University of California. CHAPTER XIII. UNITED STATES MINE LAWS. THE subject of placer mines brings up the question, How can they be obtained? If one has to purchase them, the demand will not be great; if one can locate a claim, the subject becomes interesting to the majority of gold seekers. Information upon this subject, which is well known in the mining States of the West, is entirely unknown in the East, except by those who make a busi- ness of mining. Prior to the Congressional Act of 1866 the ownership of mineral lands was retained by the Government. The agitation for the sale of such lands began in 1850, the object being to make them a source of revenue. The wise policy of leaving such lands open for private devel- opment prevailed until 1866, when the uncertainty of titles demanded a change. Possessory rights were all that could be conferred on mining claims, and this could be retained by working and the payment of a small royalty. The law was merely a license to citizens of the United States to .go upon mineral lands of the public. The Government owned the land, but placed no claim of ownership on minerals extracted, except so far as license fees or royalty was concerned. The Act of May 10, 1872, allowed any person a citizen, or one who had declared his intentions to become such, 333 334 UNITED STATES MINE LAWS and no others, to locate and hold a mining claim 1500 feet long by 600 feet wide, the claim to be by one person, 1500 linear feet along the course of the mineral vein or lode, subject to location; or any association of persons, severally qualified as above, may make joint location of such claim of 1500 feet; but in no event could a location of a vein or lode, made subsequent to the date mentioned, exceed 1500 feet along the course thereof, whatever should be the number of persons in the company. With regard to the extent of surface ground adjoining a lode or vein, and claimed for the convenient working of the same, it is provided that the lateral extent of location, made after May 10, 1872, shall in no case exceed 300 feet on each side of' the middle of the vein at the surface, and that no surface rights shall be limited by any mining regulations to less than 25 feet on each side of the middle of the vein at the surface, except where adverse rights, existing on the loth of May, 1872, may render such limitations necessary; the end lines of such claims to be in all cases parallel with each other. Thus it may be seen that no lode claim, located after May 10, 1872, can exceed a parallelogram 1500 by 600 feet, but whether surface ground of that width can be taken depends upon the local or State laws in force in the mining district; but no such laws shall limit a vein or lode claim to less than 1500 feet along its course, nor can surface rights be limited to less than 50 feet in width, unless adverse claims, existing on May 10, 1872, render such lateral limitations necessary. It is provided by the Revised Statutes that miners of each district may make such rules and regulations not in conflict with the laws ASSESSMENT WORK 335 of the United States, or of the State or Territory in which the districts are situated, governing the location, manner of recording, and amount of work necessary to hold pos- session of a claim. In order to hold a possessory right to a location made prior to May 10, 1872, not less than $100 worth of labor must be performed or improvements made thereon within one year from the date of such loca- tion, and annually thereafter; in default of which the claim will be subject to relocation by any one else having the necessary qualifications, unless the original locator, his heirs, assigns, or legal representatives have resumed work after such failure and before relocation. The expenditures required upon such claims may be made from the surface, or in running a tunnel for their devel- opment. The Act of February n, 1875, provided that where a person or company has run a tunnel for the pur- pose of developing a lode or lodes the money so expended shall be considered as expended on the said lodes, and the owners shall not be required to perform work on the surface to hold the claim. California has recently passed a new local mining law which in some respects is better than the former law, but in others falls short of what is necessary. The two most needed matters in such State laws are: What shall constitute a proper marking of a claim so as to avoid litigation? The locator of a claim should therefore not neglect his corner pillars, and make them as conspicuous and durable as possible. The other matter referred to is, What amount of assessment work shall be done to hold claims, and pre- vent persons from evading the spirit of the United States 336 UNITED STATES MINE JAWS statute in regard to assessment work? The locator of a claim should familiarize himself with the local laws of the State or Territory in which he lays out his claim ; other- wise it may be "jumped," i.e., have some one take it away from him. Individual proof of citizenship may be made by affida- vit : if a company unincorporated, by the agent's affidavit ; if a corporation, by filing a copy of the charter or certifi- cate of incorporation with the secretary of state, county recorder, or with the nearest government land officer possibly better with each. Locators against whom no adverse rights rested on the date of the Act of 1872 shall have, on compliance with general and recognized custom, the exclusive right to possession and enjoyment of the surface inclosure and of "all veins, lodes, and ledges which lie under the top or apex of such lines, extended downwards verti- cally, even though they in their descent extend outside the side lines of such surface locations." (Probably the best expert on the Apex Law is Dr. Rossiter W. Ray- mond, 1 of New York City. He is one of the framers of the law of 1875, and because of his being at one time at the head of the U. S. Government Survey, he is con- sidered to be the best-informed man on the subject.) The right to such outside parts of veins or ledge is con- fined to all that lies between "vertical planes drawn downward," as described, so continued that these planes "will intersect the exterior parts of the said veins or ledges." The surface of another claim cannot be entered by the locator or possessor of such lode or vein. 1 Law of the Apex. R. W. Raymond. A. I. M. E. Transactions. RAILROAD PATENTS 337 The land office construes the word deposit to be a general term, embracing lodes, ledges, placers, and all other forms in which valuable metals have been dis- covered. Whatever is recognized as mineral by stand- ard authorities, where the same is found in quality and quantity sufficient to render land sought to be patented more valuable on this account than for the purposes of agriculture, is treated by the land office as coming within the meaning of the act. Lands, therefore, valuable on account of borax, sodium carbonate, nitrate of soda, alum, sulphur, petroleum, and asphalt may be patented. The first section of the Act of 1872 says, "all valuable mineral deposits." The sixth section uses the term "valuable deposits." This latter section required the Supreme Court to rule petroleum a mineral deposit. This session of Congress, December, 1897, was presented with a bill drafted by Mr. A. H. Ricketts, a mining law- yer of San Francisco, the purpose of which was to recover from railroad companies those lands for which they received patents which lands were known to be mineral before the patents were issued, where they have not passed into the hands of innocent purchasers. Such a bill is eminently proper, and would take away from the railroad companies only lands which they ought never to have received and which the California Miners' Asso- ciation sought so strenuously to prevent their obtaining. 1 "It is said to be the practice of the railroad companies, when they receive patents for lands to which they know they are not entitled, to transfer them to some outside party who claims to be an innocent purchaser." "The 1 Mining and Scientific Press, Dec. 18, 1897. 338 UNITED STATES MINE LAWS miners generally are determined that the railroad com- panies shall not hold mining property that never was granted by Act of Congress." The grant of Congress referred to was, that certain railroads, because of their being built, should have each alternate additional section for ten miles back on each side of the roads as completed, but excludes all minerals except iron and coal from the grant. As fast as the lands were surveyed the companies applied for patents. Prospectors cannot obtain claims on patented lands, and consequently should keep off them. Mr. Ricketts' proposed law defines the word mineral to mean " cinna- bar, copper, lead, borax, asphalt, petroleum, oil, salt, and sulphur." Deposits of fire clay may be patented under the Act of 1872, and so may iron ore deposits be patented as vein or placer claims. Lands more valuable on account of deposits of limestone, marble, kaolin, and mica than for purposes of agriculture may be patented as mineral lands. The Act further provides that no lode claim can be recorded until after the discovery of the vein or lode within the limits of the ground claimed. The claimant should therefore, prior to recording his claim, unless he can trace the vein on the surface, sink a shaft, run a tun- nel or drift to a sufficient depth therein to discover and develop a mineral bearing vein, lode, or crevice; should determine, if possible, the general course of such vein in the direction from the point of discovery, in which direc- tion he will be governed in making the boundary of his claim on the surface; and he should give the course and LOCATING CLAIMS 339 direction as nearly as practicable from the discovery shaft on the claim to some permanent well-known points of objects, such as, for instance, stone monuments, blazed trees, the confluence of streams, etc., which may be in the immediate vicinity, and will serve to perpetuate and fix the locus of the claim, and render it susceptible of identification from the description thereon given in the record of location in the district. He should drive a post or erect a monument of stones at each corner of his sur- face ground, and at the point of discovery or discovery shaft should fix a post, stake, or board, upon which should be the name given the lode, the name of the loca- tor, the number of feet claimed, and in what direction from the point of discovery, it being essential that the loca- tion notice be filed for record. In addition to the fore- going, the description should state whether the entire claim of 1500 feet be taken on one side of the point of POST POST P O O 6.W. LOCATION STAKE % DISCOVERY SHAFT N.E. P FIG. 92. -O discovery or whether it is partly upon the other side, and in the latter case how many feet are claimed upon each side of such discovery point. Parties locating lodes are entitled to all the dips, 340 UNITED STATES MINE LAWS spurs, angles, variations, and ledges of the lode com- ing within the surface ground. The following diagram will aid the locator in his work (Fig. 92): MINER'S FORM OF NOTICE. I, John Doe, hereby give notice that I have this th day of , A.D. 18 , located this, the lode. I claim 1500 feet in and along the vein, linear and horizontal measurement. I claim 1200 feet along the vein running in a northeasterly course from the discovery shaft, and 300 feet running along the vein in a southwesterly course from the discovery shaft. I also claim 150 feet on each side of the vein from center of crevice as surface ground. JOHN DOE, Locator. In case there are more than two locators, the names of the two should be inserted, and the pronoun "we" where " I " occurs. There may be intervening claims which will lessen the length or the width of the claim. Within reason- able time after the location shall have been marked on the ground, notice thereof accurately describing the claim in manner aforesaid should be filed for record with the proper recorder of the district, who will there- upon issue the usual certificate of location. District customs are followed in this matter, and should be familiarized by the prospector. These regulations will require that a location certificate be filed with the RECORDING LOCATION 341 recorder, in the county in which the lode is situated, within a specified time after its location. FORM OF RECORDING LOCATION. STATE OF COUNTY OF ) Know all men by these Presents, That I, John Doe, the undersigned, have this th day of A.D., 1 8 , located and claimed, and by these presents do locate and claim, by right of discovery and location, in compliance with the Mining Acts of Congress, approved May igth, A.D. 1872, and all subsequent Acts, and with local custom, laws, and regulations, feet linear and horizontal measurement, on the -lode, along the vein thereof, with all its dips, angles, and variations, together with feet, run- ning from center of discovery shaft. Said dis- covery shaft being situated upon said lode, and within the lines of said claim Mining District, County of , and State of , and further described as follows: Beginning 1 at the location stake and running in a line southwesterly 300 feet, thence northwesterly to a post 150 feet. Beginning at this post and running a line north- easterly 1500 feet, to a point marked by post and pile of stones; hence southeasterly 600 feet to a post placed in the ground and marked II; hence southwesterly 1 Explanatory only. See Fig. 66. 342 UNITED STATES MINE LAWS 1500 feet to a point marked by post and stone pile; anc 1 thence 600 feet northwesterly to the point of beginning. Said lode was located on the th day of , A.D. 18 . JOHN DOE. Attest: th day of , A.D. 18 . In order to hold possessory rights to a claim of 1500 feet of vein or lode located as aforesaid, the Act requires that until a patent shall have been issued therefor not less than $100 worth of labor shall have been ex- pended annually, on the basis adopted by the local mining regulations; in default of which labor or improve- ments the claim will be subject to relocation by any other party having the necessary qualifications, unless the original locator, his heirs, assigns, or legal repre- sentatives have resumed work thereon after such failure and before such relocation. The importance of attending to these details in the matter of location, labor, and expenditure will be the more readily perceived when it is understood that failure to do so may invalidate the claim. After the patent has been granted, no more assessment work is required. Five dollars per day is usually allowed for each day of every eight hours' work performed upon a claim for the purpose of holding title or performing the neces- sary amount of work for the patent, and no other expenses shall be considered as expended for the pur- pose of holding or protecting title. PLACER CLAIMS 343 PLACER CLAIMS. The U. S. law prior to May 10, 1872, allowed each person 160 acres or a quarter section of a square mile of placer ground, if located. From the above date all placer claims shall conform as nearly as practicable with the United States system of public surveys, and no such location shall include more than 20 acres for each individual claimant. The provisions of the law are construed by the Commissioner of the General Land Office to mean that after the gth of July, 1870, no loca- tion of placer claim can exceed 160 acres, whatever may be the number of locators associated together, or whatever the local regulation of the district may allow; and that from and after May 10, 1872, no location made by an individual can exceed 20 acres, and no location made by an association of individuals can exceed 1 60 acres; which location cannot be made by a less number than eight bona-fide locators. But whether as much as 20 acres can be located by an individual, or 1 60 acres by an association, depends entirely upon the mining regulations in force in the respective districts at the date of location; it being held that such mining regulations are in no way enlarged by the statutes, but remain intact in full force with regard to the size of lo- cations, in so far as they do not permit locations in excess of the limits fixed by Congress. A local regulation is valid which provides that a placer claim, for instance, shall not exceed 100 feet square. Congress requires no annual expenditures on placer claims, leaving them subject to the local laws, rules, regulations, and customs of the mining district. 344 UNITED STATES MINE LAWS The California Law regarding Placers. Section 4, Act of 1897, reads: "The discoverer of placers or other forms of deposit, subject to location and appropriation under mining laws applicable to placers, shall locate his claim in the follow- ing manner: "First. He must immediately post, in a conspicuous place at the point of discovery thereon, a notice or certi- ficate of location thereof, containing: 11 a. The name of the claim. "b. The name of the locator or locators. "c. The date of discovery and posting of the notice hereinbefore provided for, which shall be considered as the date of location. "d. A description of the claim by reference to legal subdivisions or sections, if the location is made in con- formity with the public surveys; otherwise, a description with reference to some natural object or permanent monument as will identify the claim; and where such claim is located by legal subdivisions of the public surveys such location shall, notwithstanding that fact, be marked by the locator upon the ground, the same as other loca- tions. "Second. Within thirty days from the date of such discovery he must record such notice or certificate of location in the office of the county recorder of the county in which such discovery is made, and so distinctly mark his location on the ground that its boundaries can be readily traced. "Third. Within sixty days from the date of the dis- covery the discoverer shall perform labor upon such CALIFORNIA PLACER CLAIMS 345 location or claim in developing same to an amount which shall be equivalent in the aggregate to at least ten dollars ($10) worth of such labor for each twenty acres, or frac- tional part thereof, contained in such location or claim. "Fourth. A failure to perform such labor within said time shall cause all rights under such location to be for- feited, and the discovery thereby shall at once be open to location by qualified locators other than the preceding locators, but shall not in any event be open to location by such preceding locators, and any labor performed by them thereon shall not inure to the benefit of any subse- quent locator thereof. " Fifth. Such locator shall, upon the performance of such labor, file with the recorder of the county an affi- davit showing such performance, and generally the nature and kind of work so done." Section 5 of the same Act reads: "The affidavit pro- vided for in the last section, and the aforesaid placer notice or certificate of location when filed for location, shall be deemed and considered as prima facie evidence of the facts therein recited. A copy of such certificate, notice, or affidavit, certified by the county recorder, shall be admitted in evidence in all actions or proceedings with the same effect as the original." In locating a claim, if the above directions are closely followed, no matter what the locality, the prospector will generally have complied with the law. However, it is better to have the local laws well understood whenever possible. The United States statutes provide "water rights." i. That as a condition of sale, in the absence of legis- 346 UNITED STATES MINE LAWS lation by Congress, the legislature of a State or Territory may provide rules for working mines, involving ease- ments, drainage, and other necessary conditions; these to be expressed in the patent. 2. All prior rights, arising from possession, in the use of water, and recognized by local laws, etc., or judicial decisions, shall be regarded as vested, and shall be pro- tected. This right of way is also granted and confirmed. Damages are to accrue if a land settler's rights are inter- fered with. 3. All land patents shall be subject to vested and accrued water rights, including ditches and reservoirs. Officers of the U. S. Land Office are required to file with the General Land Office the local laws on such matters. Water privileges are, since the Act of May 10, 1872, located in the same manner as mines, subject to local regulations, i.e., by definitely locating the five acres by monuments, and recording with the district or county recorder. If the local rules and decisions of courts make the privilege forfeitable for non-use, another party may come in and claim the water right. The Federal courts have decided that the right of way to construct flumes or ditches over public lands is unquestionable. It has also been decided that the miner's right to water, within "reasonable limits," is not to be questioned. "It must be exercised, however, with due regard to the general condition and needs of the community, and cannot vest as an individual monopoly." MILL SITES 347 MILL SITES. Land, non-mineral in character, and not contiguous to the vein or lode, used by the locator and proprietor for mining or milling purposes, can be included in any application for patent, to an extent not to exceed five acres, and subject to examination and payment as fixed for the superficies of the lode. The owner of a quartz mill or reduction mill, not a mine owner in connection therewith, may also receive a mill site patent. Such sites are located under the mining act, and in compliance with local law and customs as recognized. Such possessory rights give title also to all growing timber thereon. There must in every case be given satisfactory proof of the non-mineral character of the site, and the improvements thereon must be equal to $500. A mill passes to a railroad if located on railroad land grant, and presumably to some- one else if located on another's ground. The location of a mill site is of considerable importance, and should be examined thoroughly. It must be surveyed by a Deputy Mineral Land surveyor, and recorded the same as a lode or placer claim. CHAPTER XIV. THE MINING REGULATIONS FOR THE CANADIAN YUKON. WE give below, substantially in full, the new regula- tions governing placer mining and dredging in the pro- visional district of the Yukon, as approved by Order in Council dated Ottawa, January 18, 1898. These regu- lations constitute the mining law under which all opera- tions must be conducted in that portion of the Yukon region which is in Canadian territory; and the Dominion Government is making provisions for their strict enforce- ment. The regulations are as follows : INTERPRETATION. "Free Miner" shall mean a male or female over the age of 1 8, but not under that age, or joint-stock com- pany, named in, and lawfully possessed of, a valid exist- ing free miner's certificate, and no other. "Legal Post" shall mean a stake standing not less than 4 feet above the ground and flatted on two sides for at least i foot from the top. Both sides so flatted shall measure at least 4 inches across the face. It shall also mean any stump or tree cut off and flatted or faced to the above height and size. "Close Season" shall mean the period of the year during which placer mining is generally suspended. 348 FREE-MINER'S CERTIFICATE 349 The period to be fixed by the mining recorder in whose district the claim is situated. 1 1 Mineral" shall include all minerals whatsoever other than coal. " Joint-stock Company" shall mean any company incorporated for mining purposes under a Canadian charter or licensed by the Government of Canada. " Mining Recorder" shall mean the official appointed by the gold commissioner to record applications and grant entries for claims in the mining divisions into which the commissioner may divide the Yukon District. FREE MINERS AND THEIR PRIVILEGES. 1. Every person over but not under 18 years of age, and every joint-stock company, shall be entitled to all the rights and privileges of a free miner, under these regulations and under the regulations governing quartz mining, and shall be considered a free miner upon taking out a free-miner's certificate. A free miner's certificate issued to a joint-stock company shall be issued in its corporate name. A free-miner's certi- ficate shall not be transferable. 2. A free-miner's certificate may be granted for one year to run from the date thereof or from the expira- tion of the applicant's then existing certificate, upon the payment therefor of the sum of $10, unless the certificate is to be issued in favor of a joint-stock com- pany, in which case the fee shall be $50 for a company having a nominal capital of $100,000 or less, and for a company having a nominal capital exceeding $100,000, 350 MINING REGULATIONS FOR YUKON the fee shall be $100. Only one person or joint-stock company shall be named in a certificate. 3. Gives form of miner's certificate, and adds: This certificate shall also grant to the holder thereof the privileges of fishing and shooting, subject to the provi- sions of any act which has been passed, or which may hereafter be passed, for the protection of game and fish; also the privilege of cutting timber for actual necessities, for building houses, boats, and for general mining operations; such timber, however, to be for the exclusive use of the miner himself, but such permission shall not extend to timber which may have been here- tofore or which may hereafter be granted to other per- sons or corporations. 4. Free-miner's certificates may be obtained by applicants in person at the Department of the Interior^ Ottawa, or from the agents of Dominion Lands at Winnipeg, Manitoba; Calgary, Edmonton, Prince Albert, in the Northwest Territories; Kamloops and New West- minster, in the Province of British Columbia; at Dawson City in the Yukon District; also from agents of the government at Vancouver and Victoria, British Colum- bia, and at other places which may from time to time be named by the Minister of the Interior. 5. If any person or joint-stock company shall apply for a free-miner's certificate at the agent's office dur- ing his absence, and shall leave the fee required by these regulations, with the officer or other person in charge of said office, he or it shall be entitled to have such certificate from the date of such application; and any free miner shall at any time be entitled to obtain SUBSTITUTED CERTIFICATE 351 a free-miner's certificate commencing to run from the expiration of his then existing free-miner's certificate, provided that when he applies for such certificate he shall produce to the agent, or in case of his absence shall leave with the officer or other person in charge of the agent's office, such existing certificate. 6. If any free-miner's certificate be accidentally destroyed or lost, the owner thereof may, on payment of a fee of $2, have a true copy of it, signed by the agent, or other person by whom or out of whose office the original was issued. Every such copy shall be marked "Substituted Certificate"; and unless some material irregularity be shown in respect thereof, every original or substituted free-miner's certificate shall be evidence of all matters therein contained. 7. No person or joint-stock company will be recog- nized as having any right or interest in or to any placer claim, quartz claim, mining lease, bed-rock flume grant, or any minerals in any ground comprised therein, or in or to any water right, mining ditch, drain, tunnel, or flume, unless he or it and every person in his or its employment shall have a free-miner's certificate unex- pired. And on the expiration of a free-miner's certi- ficate the owner thereof shall absolutely forfeit all his rights and interest in or to any placer claim, mining lease, bed-rock flume grant, and any minerals in any ground comprised therein, and in or to any and every water right, mining ditch, drain, tunnel, or flume, which may be held or claimed by such owner of such expired free-miner's certificate, unless such owner shall, on or before the day following the expiration of such certifi- 352 MINING REGULATIONS FOR YUKON cate, obtain a new free-miner's certificate. Provided, nevertheless, that should any co-owner fail to keep up his free-miner's certificate such failure shall not cause a forfeiture or act as an abandonment of the claim, but the interest of the co-owner who shall fail to keep up his free-miner's certificate shall, ipso facto, be and become vested in his co-owners, pro rata according to their former interests; provided, nevertheless, that a share- holder in a joint-stock company need not be a free miner, and, though not a free miner, shall be entitled to buy, sell, hold or dispose of any shares therein. 8. Every free miner shall, during the continuance of his certificate, but not longer, have the right to enter, locate, prospect, and mine for gold and other minerals upon any lands in the Yukon District, whether vested in the Crown or otherwise, except upon government reservations for town sites, land which is occupied by any building, and any land falling within the curtilage of any dwelling-house, and any land lawfully occupied for placer-mining purposes, and also Indian reservations. 9. Previous to any entry being made upon lands lawfully occupied, such free miner shall give adequate security, to the satisfaction of the mining recorder, for any loss or damage which may be caused by such entry; and after such entry he shall make full com- pensation to the occupant or owner of such lands for any loss or damage which may be caused by reason of such entry; such compensation, in case of dispute, to be determined by a court having jurisdiction in min- ing disputes, with or without a jury. SIZE OF CLAIMS 353 NATURE AND SIZE OF CLAIMS. 10. A creek or gulch claim shall be 250 feet long measured in the general direction of the creek or gulch. The boundaries of the claim which run in the general direction of the creek or gulch shall be lines along bed or rim rock 3 feet higher than the rim or edge of the creek, or the lowest general level of the gulch within the claim, so drawn or marked as to be at every point i Post "i r i! i it 03' O [03 No. i. PLAN AND SECTIONS OF CREEK AND GULCH CLAIMS. 3 feet above the rim or edge of the creek or the lowest general level of the gulch, opposite to it at right angles to the general direction of the claim for its length, but such boundaries shall not in any case exceed 1000 feet 354 MINING REGULATIONS FOR YUKON on each side of the center of the stream or gulch. (See Diagram No. i.) ii. If the boundaries be less than 100 feet apart horizontally, they shall be lines traced along bed or rim rock 100 feet apart horizontally, following as nearly as practicable the direction of the valley for the length of the valley for the length of the claim. (See Dia- gram No. 2.) 100 feet No. 2. SIDE BOUNDARIES LESS THAN 100 FT. APART. 12. A river claim shall be situated only on one side of the river and shall not exceed 250 feet in length, measured in the general direction of the river. The other boundary of the claim which runs in the general direction of the river shall be lines along bed or rim rock 3 feet higher than the rim or edge of the river within the claim so drawn or marked as to be at every point 3 feet above the rim or edge of the river opposite to it at right angles to the general direction of the claim for its length, but such boundaries shall not in any case be less than 250 feet or exceed a distance of 1000 feet from low- water mark of the river. (See Diagram No. 3.) CREEK CLAIMS 355 13. A "hill claim" shall not exceed 250 feet in length, drawn parallel to the main direction of the stream or ravine on which it fronts. Parallel lines drawn from No. 3. SECTION OF RIVER CLAIM. each end of the base at right angles thereto, and running to the summit of the hill (provided the distance does not exceed 1000 feet), shall constitute the end boundaries of the claim. 14. All other placer claims shall be 250 feet square. 15. Every placer claim shall be as nearly as possible rectangular in form, and marked by two legal posts firmly fixed in the ground in the manner shown in Diagram No. 4. The line between the two posts shall Post Post 2 $L Post Post No. 4. STAKING CREEK AND RIVER CLAIMS. be well cut out so that one post may, if the nature of the surface will permit, be seen from the other. The flatted side of each post shall face the claim, and on 356 MINING REGULATIONS FOR YUKON each post shall be written on the side facing the claim, a legible note stating the name or number of the claim, or both if possible, its length in feet, the date when staked, and the full Christian and surname of the locator. 1 6. Every alternate 10 claims shall be reserved for the Government of Canada. That is to say, when a claim is located the discoverer's claim and 9 additional claims adjoining each other and numbered consecu- tively will be open for registration. Then the next 10 claims of 250 feet each will be reserved for the Gov- ernment, and so on. The alternate group of claims reserved for the Crown shall be disposed of in such manner as may be decided by the Minister of the Interior. 17. The penalty for trespassing upon a claim re- served for the Crown shall be immediate cancellation by the mining recorder for any entry or entries which the person trespassing may have obtained, whether by original entry or purchase, for a mining claim, and the refusal by the mining recorder of the acceptance of any application which the person trespassing may at any time make for a claim. In addition to such penalty, the mounted police, upon a requisition from the mining recorder to that effect, shall take the neces- sary steps to eject the trespasser. 1 8. In defining the size of claims, they shall be measured horizontally irrespective of inequalities on the surface of the ground. 19. If any free miner or party of free miners dis- cover a new mine, and such discovery shall be estab- FREE-MINERS' RECORDER 357 lished to the satisfaction of the mining recorder, creek, river, or hill, claims of the following size shall be al- lowed, namely: To one discoverer, one claim, 500 feet in length. To. a party of two discoverers, two claims, amounting together to 1000 feet in length. To each member of a party beyond two in number, a claim of the ordinary size only. 20. A new stratum of auriferous earth or gravel situated in a locality where the claims have been aban- doned shall for this purpose be deemed a new mine, although the same locality shall have been previously worked at a different level. 21. The forms of application for a grant for placer mining, and the grant of the same, shall be those con- tained in forms H and I in the schedule hereto. 22. A claim shall be recorded with the mining recorder in whose district it is situated, within 10 days after the location thereof, if it is located within 10 miles of the mining recorder's office. One extra day shall be allowed for every additional 10 miles or fraction thereof. 23. In the event of the claim being more than 100 miles from a recorder's office, and situated where other claims are being located, the free miners, not less than five in number, are authorized to meet and appoint one of their number a " Free-miners' Recorder," who shall act in that capacity until a mining recorder is appointed by the gold commissioner. 24. The free-miners' recorder shall, at the earliest possible date after his appointment, notify the nearest Government mining recorder thereof, and upon the arrival of the Government mining recorder he shall 358 MINING REGULATIONS FOR YUKON deliver to him his records and the fees received for recording the claims. The Government mining re- corder shall then grant to each free miner whose name appears in the records an entry for his claim on form I of these regulations, provided an application has been made by him in accordance with form H thereof. The entry to date from the time the free-miners' re- corder recorded the application. 25. If the free-miners' recorder fails within three months to notify the nearest Government mining recorder of his appointment, the claims which he may have recorded will be cancelled. 26. During the absence of the mining recorder from his office, the entry for a claim may be granted by any person whom he may appoint to perform his duties in his absence. 27. Entry shall not be granted for a claim which has not been staked by the applicant in person in the manner specified in these regulations. An affidavit that the claim was staked out by the applicant shall be embodied in form H in the schedule hereto. 28. An entry fee of $15 shall be charged the first year, and an annual fee of $15 for each of the following years. This provision shall apply to claims for which entries have already been granted. 29. A statement of the entries granted and fees col- lected shall be rendered by the mining recorder to the gold commissioner at least every three months, which shall be accompanied by the amount collected. 30. A royalty of 10 per cent on the gold mined shall be levied and collected on the gross output of each ROYALTY 359 claim. The royalty may be paid at banking offices to be established under the auspices of the Government of Canada, or to the gold commissioner, or to any mining recorder authorized by him. The sum of $2500 shall be deducted from the gross annual output of a claim when estimating the amount upon which royalty is to be calculated, but this exemption shall not be allowed unless the royalty is paid at a banking office or to the gold commissioner or mining recorder. When the royalty is paid monthly or at longer periods, the deduc- tion shall be made ratable on the basis of $2500 per annum for the claim. If not paid to the bank, gold commissioner, or mining recorder, it shall be collected by the custom officials or police officers when the miner passes the posts established at the boundary of a district. Such royalty to form part of the consolidated revenue, and to be accounted for by the officers who collect the same in due course. The time and manner in which such royalty shall be collected shall be provided for by regulations to be made by the gold commissioner. 31. Default in payment of such royalty, if continued for 10 days after notice has been posted on the claim in respect of which it is demanded, or in the vicinity of such claim, by the gold commissioner or his agent, shall be followed by cancellation of the claim. Any attempt to defraud the Crown by withholding any part of the revenue thus provided for, by making false state- ments of the amount taken out, shall be punished by cancellation of the claim in respect of which fraud or false statements have been committed or made. In respect to the facts as to such fraud or false statements 360 MINING REGULATIONS FOR YUKON or non-payment of royalty, the decision of the gold commissioner shall be final. 32. After the recording of a claim the removal of any post by the holder thereof or by any person act- ing in his behalf, for the purpose of changing the boun- daries of his claim, shall act as a forfeiture of the claim. 33. The entry of every holder of a grant -for placer mining must be renewed and his receipt relinquished and replaced every year, the entry fee being paid each time. 34. The holder of a creek, gulch, or river claim may, within 60 days after staking out the claim, obtain an entry for a hill claim adjoining it, by paying to the mining recorder the sum of $100. This permission shall also be given to the holder of a creek, gulch, or river claim obtained under former regulations, pro- vided that the hill claim is available at the time an application is made therefor. 35. No miner shall receive a grant of more than one mining claim in a mining district, the boundaries of which shall be defined by the mining recorder, but the same miner may also hold a hill claim, acquired by him under these regulations in connection with a creek, gulch, or river claim, and any number of claims by purchase; and any number of miners may unite to work their claims in common, upon such terms as they may arrange, provided such agreement is regis- tered with the mining recorder and a fee of $5 paid for each registration. 36. Any free miner or miners may sell, mortgage, or dispose of his or their claims, provided such dis- ABANDONED CLAIM 361 posal be registered with, and a fee of $2 paid to, the mining recorder, who shall thereupon give the assignee a certificate in the form J in the schedule hereto. 37. Every free miner shall during the continuance of his grant have the exclusive right of entry upon his own claim for the mine- like working thereof, and the construction of a residence thereon, and shall be entitled exclusively to all the proceeds realized therefrom, upon which, however, the royalty prescribed by these regula- tions shall be payable; provided that the mining recorder may grant to the holders of other claims such right of entry thereon as may be absolutely necessary for the working of their claims, upon such terms as may to him seem reasonable. He may also grant permits to miners to cut timber thereon for their own use. 38. Every free miner shall be entitled to the use of so much of the water naturally flowing through or past his claim, and not already lawfully appropriated, as shall, in the opinion of the mining recorder, be neces- sary for the due working thereof, and shall be entitled to drain his own claim free of charge. 39. A claim shall be deemed to be abandoned and open to occupation and entry by any person when the same shall have remained unworked on working days, excepting during the close season, by the grantee thereof or by some person on his behalf for the space of 72 hours, unless sickness or other reasonable cause be shown to the satisfaction of the mining recorder, or unless the grantee is absent on leave given by the mining recorder, and the mining recorder, upon obtaining evidence satisfactory to himself that this provision is not 362 MINING REGULATIONS FOR YUKON being complied with, may cancel the entry given for a claim. 40. If any cases arise for which no provision is made in these regulations, the provisions of the regulations governing the disposal of mineral lands other than coal lands, approved by His Excellency the Governor in Council on November 9, 1889, or such other regulations as may be substituted therefor, shall apply. (Appended to Section 40 are the forms for applications, certificates, etc., referred to in the text.) REGULATIONS GOVERNING RIVER-BED DREDGING FOR GOLD. The following are the regulations for the issues of leases to persons or companies who have obtained a free-miner's certificate in accordance with the provi- sions of the regulations governing placer mining in the Provisional District of Yukon, to dredge for minerals other than coal in the submerged beds or bars of rivers in the Provisional District of Yukon, in the Northwest Territories : i. The lessee shall be given the exclusive right to subaqueous mining and dredging for all minerals with the exception of coal in and along an unbroken extent of five miles of a river following its sinuosities, to be measured down the middle thereof, and to be described by the lessee in such manner as to be easily traced on the ground; and although the lessee may also obtain as many as five other leases, each for an unbroken extent of five miles of a river, so measured and described, no more than six such leases will be issued in favor of an TERM OF LEASE 363 individual or company, so that the maximum extent of river in and along which any individual or company shall be given the exclusive right above mentioned, shall under no circumstances exceed 30 miles. The lease shall provide for the survey of the leasehold under instructions from the Surveyor General, and for the filing of the returns of survey in the Department of the Interior within one year from the date of the lease. 2. The lease shall be for a term of 20 years, at the end of which time all rights vested in, or which may be claimed by the lessee under his lease, are to cease and determine. The lease may be renewable, how- ever, from time to time thereafter in the discretion of the Minister of the Interior. 3. The lessee's right of mining and dredging shall be confined to the submerged beds or bars in the river below low-water mark, that boundary to be fixed by its position on the first day of August in the year of the date of the lease. 4. The lease shall be subject to the rights of all persons who have received or who may receive entries for claims under the Placer- mining Regulations. 5. The lessee shall have at least one dredge in operation upon the five miles of river leased to him, within two seasons from the date of his lease, and if, during one season when operations can be carried on, he fails to efficiently work the same to the satisfaction of the Minister of the Interior, the lease shall become null and void unless the Minister of the Interior shall otherwise decide. Provided that when any company or individual has obtained more than one lease, one 364 MINING REGULATIONS FOR YUKON dredge for each 15 miles or portion thereof shall be held to be compliance with this regulation. 6. The lessee shall pay a rental of $100 per annum for each mile of river so leased to him. The lessee shall also pay to the Crown a royalty of 10 per cent on the output in excess of $15,000, as shown by sworn returns to be furnished monthly by the lessee to the gold commissioner during the period that dredging operations are being carried on; such royalty, if any, to be paid with each return. 7. The lessee who is the holder of more than one lease shall be entitled to the exemption as to royalty provided for by the next preceding regulation to the extent of $15,000 for each five miles of river for which he is the holder of a lease; but the lessee under one lease shall not be entitled to the exemption as to royalty provided by the next two preceding regulations, where the dredge or dredges used by him have been used in dredging by another lessee, or in any case in respect of more than 30 miles. 8. The lessee shall be permitted to cut free of all dues, on any land belonging to the Crown, such timber as may be necessary for the purposes of his lease, but such permission shall not extend to timber which may have been heretofore or may hereafter be granted to other persons or corporations. 9. The lessee shall not interfere in any way with the general right of the public to use the river in which he may be permitted to dredge, for navigation and other purposes; the free navigation of the river shall not be impeded by the deposit of tailings in such manner as to LEASE RESTRICTIONS 365 form bars or banks in the channel thereof, and the current or stream shall not be obstructed in any material degree by the accumulation of such deposits. 10. The lease shall provide that any person who has received or who may receive entry under the Placer-min- ing Regulations shall be entitled to run tailings into the river at any point thereon, and to construct all works which may be necessary for properly operating and work- ing his claim. Provided that it shall not be lawful for such person to construct a wing dam within 1000 feet from the place where any dredge is being operated, nor to obstruct or interfere in any way with the operation of any dredge. 11. The lease shall reserve all roads, ways, bridges, drains, and other public works, and all improvement now existing, or which may hereafter be made in, upon, or under any part of the river, and the power to enter and construct the same, and shall provide that the lessee shall not damage nor obstruct any public ways, drains, bridges, works, and improvements now or hereafter to be made upon, in, over, through, or under the river; and that he will substantially bridge or cover and protect all the cuts, flumes, ditches, and sluices, and all pits and dangerous places at all points where they may be crossed by a public highway or frequented path or trail, to the satisfaction of the Minister of the Interior. 12. That the lessee, his executors, administrators, or assigns, shall not nor will assign, transfer, or sublet the demised premises, or any part thereof, without the con- sent in writing of the Minister first had and obtained. 366 MINING REGULATIONS FOR YUKON UNITED STATES LAW RELATIVE TO RIVER DREDGING. Rivers or streams in a defined channel belong to the State. To dredge river beds requires either a grant or prescription from the State, in the absence of any definite legislation regulating this industry. There is scarcely any doubt that the State would grant permission to mine any river bed within her borders provided navigation were not hindered or obstructed or riparian rights inter- fered with, but such sanction should be obtained prior to commencing work. In the case of a non-navigable stream flowing within the borders of one's land, the land under the water belongs to the landowner; or the water, to the State. In such a case the right to dredge is un- questionable. Or in case of two landowners adjoining on opposite sides either one may dredge his half and be convicted of trespass if he oversteps the boundary. The owner or owners must not overstep the mark and injure land or watercourse below their property, other- wise they may be enjoined. The dredging company may purchase a piece of land and work their dredge along the river bank. They must not, however, change the course of the stream or divert it from the riparian owner opposite, although they may work as far inland on their own property as they desire, and have the usufruct of the stream. The chances are that dredgers if they pollute the streams or make them muddy will have trouble with riparian owners in the States for creating a nuisance. The washing of ore and discoloring the water of the New River, Virginia, has WATER RIGHTS 367 caused much comment, and an attempt has been made in Congress to suppress it. The Anthracite Mine Operators are compelled to impound the material resulting from coal washing, where once they permitted it to run into the streams and rivers. If the stream belongs to the public domain, twenty acres can be located, or a dredger may work up and down the stream (provided it does not work on a located claim) without interference. Navigable rivers are under the supervision of the United States ; other streams belong to the States through which they flow. Mineral lands under rivers belong to the State, and can be obtained from the State by proper legal proceedings. CHAPTER XV. GOLD TABLE AND HYDRAULICS. THE following tables have been computed by data obtained from careful experiments made by the ablest engineers. They will therefore assist the unskilled as well as the skilled in many problems. However, to thoroughly understand the subject, one should purchase a text-book on hydraulics. These tables are reliable, and will prove correct as far as they go. The whole subject has been touched upon in the preceding pages, so that any one who has carefully read them should understand the tables at a glance, and be able to apply them in practice. EXPLANATION OF TABLE. The table furnishes an exceedingly simple method of determining the value of free gold in a ton of gold- bearing quartz, or a cubic yard of auriferous gravel. Take a sample of four (4) pounds of quartz, pulverize it to the usual fineness for horning, wash it carefully by batea or other means, amalgamate the gold by the appli- cation of quicksilver, volatilize the quicksilver by blow- pipe or otherwise, weigh the resulting button, and the 368 GOLD TABLE value given in the table opposite such weight will be the value in free gold per ton of 2000 pounds of quartz. Example. Sample of four pounds produces button weighing one grain, the fineness of the gold being 830; then the value of one ton of such quartz will be $17.87. If the sample of 4 pounds should produce a button weighing say two and four- tenths (2^) grains, then the value of such quartz would be (875 fine) as follows, viz.: Opposite 2 grains, 875 fine, value $37.68 Opposite T % grains, 875 fine, value 7.53 Total value per ton (2000 Ibs.) . .$45.21 GOLD TABLE FOR DETERMINING THE VALUE OF FREE GOLD PER TON (2OOO LBS.) OF QUARTZ OR CUBIC YARD OF GRAVEL, Prepared by MELVILLE AT WOOD, Esq., F.G.S., Consulting Mining Engineer. Weight Fineness, Fineness, Fineness, Fineness, Washed Gold. 780. 830. 875. 920. 4-lb Sample. Grains. Value per Oz. $16.12. Value per Oz. $17.15. Value per Oz. $18.08. Value per Oz. 19.01. 5 grains $83.97 $89.36 $94.20 $99.05 4 67.18 71.49 75 -3 6 79.24 3 50-38 53 -61 5 6 -5 2 59-43 2 33-59 35-74 37.68 39.62 I 16.79 17.87 18.84 19.81 9 15.11 16.08 16.95 17.82 .8 13-43 14.29 15-07 15.84 7 n-75 12.51 13-19 13.86 .6 10.07 10-73 11.30 11.88 5 8.40 8-93 9.42 9.90 4 6.71 7.14 7-53 7.92 3 5-3 5-30 5-65 5-94 .2 3-36 3-57 3-76 3-96 . I 1.68 1.78 1.88 1.98 370 GOLD TABLE AND HYDRAULICS GOLD VALUE OF A CUBIC YARD OF GRAVEL. To determine the gold value of a cubic yard of aurif- erous gravel the foregoing table can be used. Take a sample of sixty (60) pounds of gravel, pul- verize it, and carefully wash it by batea, pan, or other- wise; amalgamate the gold, volatilize the quicksilver, weigh the button, and in column in foregoing table, oppo- site the weight, will be found the gold value of a cubic yard of the gravel. Example. Sample of sixty pounds produces button weighing one grain, the fineness of the gold being 780; then the value of one cubic yard of such gravel would be $1.67. This is arrived at by pointing off one point, or dividing the value given in table by 10. If the sample of sixty pounds yields a button weighing i grain and two-tenths (itk grains), then the value of the gravel per cubic yard would be gold being 920 fine as follows : Opposite i grain, 920 fine, value $1.98 Opposite tiF grain, 920 fine, value .40 + Total value cubic yard .... $2.38 + This table is prepared upon the following basis of weights, viz. : A sample of 4 pounds of quartz is the one- five-hundredth part in weight of a ton of 2000 pounds, and the gold values given are reduced to this proportion. Eighteen cubic feet of gravel in bank will weigh one ton, or 2000 pounds, and a cubic yard, or 27 cubic feet, will weigh 3000 pounds, or i J tons; and 60 pounds being the one-fiftieth part of the weight of a cubic yard, then HYDRAULICS 371 the relative proportion of the weight of quartz to gravel is as 50 to 500, or i to 10. HYDRAULICS. i gallon of water =231 cubic inches and weighs 8.3389 pounds, figured at 8J pounds. i cubic foot of water = 1728 cubic inches and weighs 62.3793 pounds, figured at 62.5. contains 7.48052 gallons, usually figured at 7.5. A column of water 2.31 feet high gives i Ib. pressure on each square inch of its base. A column of water i ft. high will give a pressure of .434 Ib. on each square inch of base. Usually reckoned at 5 Ibs. per ft. in height. Doubling the diameter of a pipe increases its area four times, hence its capacity. Doubling the diameter of a pipe increases its frictional rubbing-surface two times. To double the quantity of water flowing through a pipe under a given head requires eight times the power. 27 154 inches of water will spread i inch deep over i acre of ground, and weigh 101 tons. A foot-pound of work is the expenditure of power required to raise one pound one foot high in one minute. A horse-power is 33,000 foot-pounds, or what a strong horse can do 10 hours daily every minute in the day. Average horses can do but 22,000 ft. -Ibs per minute. To find the horse-power required to raise water: Multiply the number of pounds of water to be raised per minute by the height from the level of the water to the level of discharge and divide by 33,000. 372 GOLD TABLE AND HYDRAULICS TABLES FOR CALCULATING THE HORSE-POWER OF WATER. MINERS'-INCH TABLE. The following table gives the horse-power of one miners' inch of water under heads from one up to eleven hundred feet. This inch equals i% cubic feet per minute. Head in Feet. Horse-power. Head in Feet. Horse-power. I .0024147 320 .772704 20 .0482294 330 .796851 30 .072441 340 .820998 40 .096588 350 .845145 50 120735 360 .869292 60 .144882 370 893439 70 . 169029 380 .917586 80 .193176 390 941733 90 .217323 400 .965880 100 .241470 410 .990027 no .265617 420 .014174 120 .289764 430 038321 130 3I39II 440 .062468 140 .338058 450 .086615 150 .362205 460 .110762 1 60 386352 470 134909 170 .410499 480 .I59 56 180 .434646 49 . 183206 190 .458793 500 .207350 200 .482940 520 255644 2IO .507087 540 303938 22O 531234 560 .352232 230 .555381 580 .400526 240 .579528 600 .448820 250 .603675 650 569555 260 .627822 700 . 690290 270 .651969 750 .811025 280 .676116 800 .931760 290 . 700263 900 2.173230 300 .724410 1000 2.414700 310 748557 1 100 2.656170 WHEN THE EXACT HEAD IS FOUND IN ABOVE TABLE. Example. Have loo-foot head and 50 inches of water. How many horse-power? By reference to above table the horse-power of I inch under 100 feet head is .241470. This amount multiplied by the number of inches, 50, will give 12.07 hoise power. CUBIC-FEET TABLE 373 CUBIC-FEET TABLE. The following table gives the horse-power of one cubic foot of water per minute under heads from one up to eleven hundred feet: Head in Feet. Horse-power. Head in Feet. Horse- power. I .0016098 320 .515136 20 .032196 330 .531234 30 .048294 340 547332 40 .064392 350 563430 50 .080490 360 .579528 60 .096588 370 .595626 70 .112686 380 .611724 80 .128784 390 .627822 QO .144892 400 .643920 100 .160980 410 .660018 no .177078 420 .676116 120 .193176 430 .692214 130 .209274 440 .708312 140 .225372 450 .724410 150 .241470 460 .740508 160 .257568 470 .756606 170 .273666 480 .772704 1 80 .289764 490 .788802 190 .305862 500 . 804900 200 .321960 520 837096 2IO. .338058 540 .869292 220 .354156 560 .901488 230 .370254 580 933684 240 .386352 600 .965880 250 .402450 650 046370 260 .418548 700 .126860 270 .434646 750 .207350 280 .450744 800 .287840 290 .466842 900 .448820 300 .482940 IOOO .609800 310 .499038 IIOO .770780 WHEN EXACT HEAD IS NOT FOUND IN TABLE. Take the horse-power of i inch under i-foot head and multiply by the number of inches, and then by number of feet head. The product will be the required horse-power. Note. The above formula will answer for the cubic-feet table, by substituting the equivalents therein for those of miners' inches. Horse-power given in above table equal 85 per cent of theoretical power. 374 GOLD TABLE AND HYDRAULICS FLOW OF WATER THROUGH CLEAN IRON PIPES. Remarks. In the analysis of the flow of water, the total head is divided into three parts, : viz., ist, that por- tion of the head due to the velocity; 2d, that portion which overcomes the resistance of entry; and 3d, that portion which overcomes the resistance within the pipe. In long pipes, the two former portions as compared with the latter portion of the total head are quite small. In this table the greatest velocity in any pipe is 13.445 feet per second, due to 4.2 feet, the sum of the first and second portions of the total head, while the third portion of the head is 211.2 feet. The head or fall in this table refers to the third portion of the total head. This table has been computed on the assumption that the length of any pipe is not less than 1000 times its diameter. Question: The fall being 52.8 feet per mile, what will be the flow through a pipe 22 inches diameter, in cubic feet, also in miner's inches? Answer: In this table find in first column 52.8 feet, opposite which in column headed 22 Inches will be found the required quantity, viz., 21.06 cubic feet, which multiplied by 50 gives 1053 miner's inches. Question : The diameter of the pipe being 24 inches, what fall will be required for the pipe to carry 1000 miner's inches? Answer: In this table, in column headed 24 Inches, find that number which multiplied by 50 will make the 1000 miner's inches given. In this case the nearest FLOW THROUGH PIPES 375 number is 20.42, opposite which in column headed Fall per Mile will be found 31.68 feet, the fall required. Question: In carrying 1050 inches of water to a hydraulic mine in a pipe 27 inches diameter, having a fall of 95.04 feet to the mile, what will be the effective head at the mine ? Answer: In this table, in column headed 27 Inches, find that number which multiplied by 50 will make 1050 approximate miner's inches. In this case we have 21.13 cubic feet, opposite which in column headed Fall per Mile we find 18.48 feet, which is the head per mile lost in carrying the water. Subtracting this from the given fall or head gives the effective head. Thus 95.04 18.48 = 76.56 feet effective head. Question : There being 7.5 gallons in a cubic foot, and 86,400 seconds in a day (twenty-four hours), the fall 7.39 feet per mile, how many gallons will a pipe 40 inches diameter carry per day? Answer: In this table, in column headed 40 Inches and opposite 7.39 feet headed Fall per Mile, will be found 37.57 cubic feet flow per second. Then 37.57 X 7.5 X 86,400 = 24,345,360 gallons. GENERAL RULE. The velocity per second is equal to 50 times the square root of the product of the head and diameter in feet, divided by the sum of the length and 50 times the diameter of the pipe in feet. SHORT PIPES. This rule applies to both long and short pipes, and is approximately accurate if the diame- ter does not exceed two feet. 376 GOLD TABLE AND HYDRAULICS TABLE SHOWING FLOW OF WATER PER SECOND THROUGH CLEAN IRON PIPES. Diameters. Fall Fall Per Mile. Per Rod. Feet. Ft. In. Mfe Kin. i in. i^in. i%in. 2 in. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. 21 . 12 o 0.792 .02584 26.40 On QQO .02014 .02924 31.68 V'W'-' o .188 .01460 .02270 O^27J. jfi 06 o ^06 .oi?8^ .02426 vfjfm O'1AQ2 j"*- y w 42.24 v jyj o .584 .00567 \j j. 3 tne additional head required. TABLE SHOWING ADDITIONAL HEAD REQUIRED TO OVERCOME THE RESISTANCE OF ONE ANGULAR BEND. Veloc- Angles of Deflection. ity per Sec- ond. i 5 Head. 30 Head. 40 Head. 60 Head. 90 Head. i2oHead. Feet. Feet. Feet. Feet. Feet. Feet. Feet. i .0002 .0005 .002 .006 .015 .029 2 .0010 .0019 .009 .023 .061 .116 3 .0022 .0042 .019 .051 138 .260 4 .004 .008 035 .090 245 .462 5 .006 .012 054 .141 .382 723 6 .009 .017 .078 .204 550 1.04 7 .012 .023 .106 .277 749 1.42 8 .Ol6 .030 .138 .362 .978 1-85 10 .025 .047 .216 .565 I -53 2.89 IS .056 .105 .486 1.27 3-44 6.50 20 .099 .186 .863 2.26 4.85 11.56 25 155 .291 i-35 4-45 9-55 18.06 3 .224 .419 1.94 5-09 13-75 26.01 40 .398 745 3-45 9.04 24.45 46.23 5 .621 1.17 5-40 14-13 38.20 73-93 75 1.40 2.62 12.14 31-79 85-95 162.5 100 2. 4 8 4.66 21.58 5 6 -5 2 152.8 289.0 iS 5-59 10.48 48.57 127.2 343-7 650.2 200 9.94 18.63 86.32 226. i 611.1 1156. 300 22.36 41.92 194.20 508.7 1092. 2601. ADDITIONAL HEAD NECESSARY TO OVERCOME THE RESISTANCE OF ONE CIRCULAR BEND. Question: The radius of the pipe being to the radius of the bend in the ratio of 1:5, the number of degrees OPEN CHANNELS 383 in the bend being 90 degrees, and the velocity 75 feet per second, what is the additional head required to overcome the resistance of the bend ? Answer: In this table, in first column, headed Velocity per Second, find 75 feet, opposite which, in column headed 1:5, 90, is found 6.03 feet, the required head. Question : The radius of the pipe being to the radius of the bend in the ratio of 2:5, the number of degrees in the bend being 1 20 degrees, and the velocity per second 100 feet, what is the additional head required to over- come the resistance of one bend ? Answer: In this table, opposite 100 feet velocity, will be found in column headed 2:5, 120, the re- quired number, viz., 21.34 feet. RELATIVE CARRYING CAPACITY OF OPEN CHANNELS WHOSE SECTIONAL AREAS ARE EQUAL TO EACH OTHER BUT OF DIFFERENT FORMS. The form in which the bottom width is made equal to one of the sides, and in which the base to the perpen- dicular of the side slope is as 3 : 4, has been adopted as the standard form when the ground will admit, it being the simplest of construction. The relative carrying capacity for trapezoidal form Base : depth of slope 1:3:4; bottom width : depth : : 5 .-4. Coefficient of capacity, 1000. Trapezoidal form Base : depth of slope : : i : i ; bottom width = depth, .994. Coefficients: flume, 2:1, .961; semi- hexagonal, 1.008; square, .925; semicircular, 1.056. 384 GOLD TABLE AND HYDRAULICS Question: The fall being 6 feet per mile, the sectional area of a square flume 8 square feet, what will be its carrying capacity per second? Answer: In table showing Flow of Water in Open Channels Base to Perpendicular of Side Slopes being as 3 : 4, in column of Fall per Mile, find the given fall 6 feet, opposite which in column headed sectn. 8. o square feet is found 13.65 cubic feet. This multi- plied by the coefficient for a square, viz., .925, gives 13.64 X .925 = 12.63 cubic feet. Remarks. The tables for the flow of water in open channels have been computed upon the assumption that the canals are smooth and straight. FLOW OF WATER THROUGH NOZZLES. Question: The head being 125 feet, how many cubic feet per second will a nozzle 4 inches in diameter dis- charge? How many miners' inches? Answer: In this table find in the first column the given head, 125 feet, opposite which, in column headed 4 Inches, will be found the required quantity, viz., 7.28 cubic feet X 50 = 364 miner's inches. Question: Between the inlet and the nozzles of a hydraulic pipe 3 feet in diameter the distance is five miles and the total fall 275 feet. The pipe is to carry 2000 miners' inches of water, which is to be discharged through two " Little Giants," or nozzles equal in size. What will be the loss of head by the resistance in the main pipe? What will be the size of each nozzle? Answer: In table showing Flow of Water Through FLOW THROUGH NOZZLES 385 Clean Iron Pipes find in column headed 36 Inches that number which multiplied by 50 will make 2000, the given number of miner's inches. In this case 40.86 approximates sufficiently near, opposite which, in column, headed Fall per Mile, is found 14.78 feet, the loss of head per mile. Multiply this by 5, the length of the pipe, and we have 14.78 X 5 = 73.9 feet, the loss of resistance in the pipe 5 miles long. Subtracting this from the total head, 275 73.9 = 201.1 feet remaining head. Again, in the table find 200 nearest 201.1 feet in column headed Head, opposite which, in column, headed 6 Inches, is found 20.64, which multiplied by 50 gives 1.032, or approximately 1000 miner's inches, which each nozzle is required to discharge. Hence the nozzles are to be 6 inches in diameter each. 386 GOLD TABLE AND HYDRAULICS rt. OMCtmoOM~ino"c4NOOOoooicoOcoOC4co *IT< OOOOOMM04cot>i04OcOMO\OO^O ' ' M' 04" 04 lAr^oo M 04 M co r^ 04 co M 04 'M M WWwOOOWM04^tCOCOO^TtCOOCOOO^CO M 04 M COO "t M Tt o t"** f^ co 04 co t^ o o r^ _ in 2 ^ OQnM04comoOTj-04OOMOOt^OTtO OOOOOOOOM04 TtO 0> f>-0 O O O O O ^^^ " M C4 O O O v8 ^j U^MCO>CO04MMCOQO COCO O fit O 04 T^CO CO O^O Tt CO O CO CO O^ CO OOOOOM04cOTtcocoOcoqcoc> O W O tfc| 'MCOIA04M E . C4 00 & TT Q \nV-u OO'-'COlOt-xOCOMCOlOTtCO04OO0404 S3 v ..9999 MMP ! T ? CO C> rj- CO O Tt 04 I<.CO 3 8 & O TtCO CO CO CO rt Q TtCO TtO CO 10 v *j O O M 04 co ^r> r*** s ^ 04 t^ o^ o^co co o ..a x^^S^^ 1 ? *C CO N ! *? M 04 COCO Tt 04 r>CO M co m 04 M COO M CO O IOO 04 M t^O 04 **W OOOMO4fOr>vOOTt04OOMCOCOMM w o ti M 04 O O -rf 04 o" o" oTvo" ^ _ _ oooqooM04TtoMt^.qMqxn M M Tt t^.O CO vg M 04 O M M OJ CO< W ofc< 04COCOTt04 S) M CO M co ^ OuiOw>OOOnQOQQ MMWNCOTtnt^O>OOO M M M CO FLOW OF WATER IN OPEN CHANNELS 387 FLOW OF WATER IN OPEN CHANNELS. Question : The dimensions of a canal being, top width n feet, bottom width 5 feet, depth 4 feet, and the fall per mile 8 feet. Required the number of inches, miners' measure, that it will carry. Answer : In this table, in column headed " Fall per Mile," find 8 feet, opposite which in column headed with given specifications (n, 5, 4) is found 104.8 cubic feet, the flow per second. This mul- tiplied by 50, the number of miners' inches equal to one cubic foot flow per second, gives 104.8 X 5 = 5240 miners' inches required. TABLE SHOWING FLOW OF WATER IN OPEN CHANNELS, BAS. TO PERPENDICULAR OF THE SIDE SLOPES BEING AS 3 : 4. T 2.2 ft. T 3.3 ft. T 4.4 ft. T 5-5 ft. T66ft. T 7.7 ft. T 8.8 ft. Fall Fall B 1.0 ft. D .8 ft. B 1.5 ft. Dl.2ft. B 2.0 ft. D 1.6 ft. B 2.5 ft. D 2.0 ft. B 3. oft. D2 4 ft. B 3.5 ft. D 2.8 ft. B 4.0 ft. D 3.2 ft. Mile. Ft. per Rod. In. Section 1.28 sq. ft. Section 2.88 sq. ft. Section 5.12 sq. ft. Section 8.0 sq. ft. Section ".52 sq. ft. Section 15-68 sq. ft. Section 20.48 sq. ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. I 0375 45 1-33 2.67 5-57 9-05 13.46 20.26 2 .0750 63 1.88 3-87 7.88 12. 80 19.04 28.64 3 .1125 77 2.30 4-74 9-65 I5.67 23.32 35-08 4 .I5CO .89 2.65 5-47 11.14 18.52 26.93 40.51 5 .1875 .00 2-97 6.12 12.46 2O.24 30.11 45.30 6 .2250 .09 3-25 6.70 13-65 22.17 32.98 49.62 7 .2625 .18 3-42 7-24 14.74 23-94 35.63 53-58 8 .3000 .26 3-75 7-73 15-75 25.60 38.08 57-28 9 3375 34 3.98 8.21 16.71 27-15 40-39 60.76 10 3750 .41 4-19 8.65 17.61 28.62 42-57 64.05 ii .4125 .48 4.40 9.07 18.47 30.02 44-55 67.18 12 4500 54 4.60 9.48 19.30 31-35 46.64 70.65 13 .4875 .61 4-78 9.86 20.08 32.63 48.54 73-03 14 .5250 67 4.96 10.24 20.84 33.87 50.38 75-79 15 .5625 73 5-14 10.60 21-57 35-05 52.14 78.44 16 .6OOO 78 5-31 10.94 22.27 36.2O 53.86 81.02 17 .6375 .84 5-47 11.28 22.96 37.31 55-51 83-51 18 .6750 .89 5-63 1 1. 60 23.63 38.39 57-11 85.93 19 .7125 94 5-78 11.92 24.28 39-44 58.58 88.29 20 .7500 99 5 93 12.23 24.91 40.47 60.21 90.58 21 .7875 2.04 6.08 12.54 25-53 41.47 61.70 92.82 22 .8250 2.09 6.22 12.83 26.12 42.45 63.15 95-00 23 .8625 2.14 6.36 13.12 26.71 43-40 64.57 97.15 24 .QOOO 2 18 6.50 13.40 27.29 44-34 65.95 99-23 25 9375 2.23 6.63 13.68 27.98 45-24 67.32 101.28 In Tables, T signifies top width; B, bottom width; D, depth. 388 GOLD TABLE AND HYDRAULICS TABLE SHOWING FLOW OF WATER IN OPEN CHANNELS, BASE TO PERPENDICULAR OF THE SIDE SLOPES BEING AS 3 : 4. (continued.) Tg.gft. T ii ft. T 13.2 ft. T 16.4 ft. T 17.6 ft. T 19. 8 ft. T 22 ft. Fall per Mile. Fall R^d. B 4-5 ft. D 3.6 ft. Section B 5 ft. D 4 ft. Section B 6.0 ft. D 4.8 ft. Section B 7.0 ft. D 5.6ft. Section B 8.0 ft. D 6.4ft. Section B 9.0 ft. D 7.2 ft. Section B 10 ft. D 8ft. Section Ft. In. 25.92 32, 46.09 62.72 81.92 103 68 128 sq. ft. sq. ft. sq. ft. sq. ft. sq. ft. sq. in. sq. ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. I 0375 28.04 37-1 58.4 96.5 138.3 189.2 26l.2 2 .0750 39-67 52.4 82.7 136.4 195.7 267.6 369.4 3 .1125 48.59 64.2 101.4 167.1 239-6 327-7 451-3 4 .1500 56.IO 74.1 II7.I 192.9 276.7 378.4 522.3 5 .1875 62.71 82.9 130.9 215.7 309.3 423.1 584-0 6 .2250 68.70 90.8 143-4 236.3 338.8 463.5 639.8 7 .2625 74.19 98.1 154.8 255.3 366.0 500.5 691.0 8 .3000 79-53 104.8 165.5 272.9 391-2 535.1 738.7 9 3375 84.14 III. I 175-6 289.4 415.0 567.6 783.5 10 3750 88.68 II7-I 185.1 305.0 437-4 598.2 825.9 ii .4125 93-02 122.9 194.1 3I9-9 458.7 613.2 866.2 12 .4500 97-15 128.4 202.8 334-2 479-1 655.4 925-6 13 .4875 101.13 '133 6 211. 1 347-8 498.7 682.1 941.7 14 .5250 104.94 138.7 2I9.O 360.9 517.5 707.8 977-2 15 5625 108.63 I43-S 226.6 373-6 535-7 732.8 1011.5 16 .6000 112.18 148.2 234.1 385-9 553-3 756.7 1044.7 17 .6375 115-64 152.4 241.3 397-8 570.3 780.1 1076.9 18 .6750 118.99 157-2 248.3 409-3 586.9 802.7 1 108.1 19 .7125 122.26 161.5 255-1 420.5 601.5 824.8 1138.4 20 .7500 125.43 165-7 261.7 431-4 618.5 846.1 1168.0 21 .7875 1 128.53 169.8 268.2 442.0 633.9 867.0 1196.8 22 .8250 I3L55 173.8 274.5 452.5 648.8 8874 1225.0 23 .8625 134.51 177-7 280.7 462.9 663.4 907.4 1252.6 24 .9000 137.40 181.5 286.7 472.6 677.7 926.0 1279-5 25 9375 140. 24 185.3 292.6 482.3 691.6 946.0 1306.0 In Tables, T signifies top width; B, bottom width; D, depth. FLOW OF WATER IN OPEN CHANNELS 389 FLOW OF WATER IN OPEN CHANNELS (Continued.) Question : Required the number of cubic feet of water that will flow in a canal whose top width is 40 feet, bottom width 20 feet, depth 5 feet, and whose fall is 2 feet per mile. Answer : In this table, in column "Fall per Mile," find 2 feet, opposite which in column headed with the given specifications (40, 20, 5) is found the required flow, viz., 376.1 cubic feet. TABLE SHOWING FLOW OF WATER IN OPEN CHANNELS, BASE TO PERPENDICULAR OF THE SIDE SLOPES BEING AS 2 I 1. T6ft. T 9 ft. T 12 ft. T 16 ft. T 22 ft. T 28 ft. T 4 oft. B 2ft. B 3 ft. B 4 ft. B6ft. B 10 ft. B 12 ft. B 20 ft. Fall Fall D i ft. D 1.5 ft. D 2ft. D 2.5 ft. D 3 ft. D 4 ft. D 5 ft. per Mile. per Rod. Section Section Section Section Section Section Section Feet. Feet. 4 9 16 27.5 48 3 150 sq. ft. sq. ft. sq. ft. sq. ft. sq. ft. sq. ft. sq. ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. 5 .01875 1.27 3-85 8.63 l8.II 8.79 78.2 I88.I .6667 .0250 1.46 4.44 9.96 20.91 44-79 90-3 217.2 .8333 .03125 1.6 3 4.96 11.14 23.38 50.08 IOI.O 242.8 i 0375 1.79 5-44 12. 2O 25.61 54-86 no. 6 266.0 1.25 .046875 2.OO 6.08 13.64 28.68 61.32 123.7 297.4 1-5 .05625 2.1 9 6.67 14.96 3L34 67.26 135.7 326.1 i-75 .065625 2.37 7.19 I6.I4 33-88 72.57 146.4 351-8 2 .0750 2.53 7.69 17.26 36.22 77.58 156.5 376.1 2.25 .084375 2.68 8.16 18.30 38.42 82.29 165.9 399-0 2-5 09375 2.83 8.60 19.29 40.50 86.72 174.9 420.6 3 .1125 3.10 9.42 21.14 44.36 95-00 191.6 460.7 3-5 .13125 3-35 10.17 22.83 47.91 102.6 207.0 497.6 4 .I5OO 3-58 10.87 24.41 51.22 109.7 221.3 531-9 4-5 .16875 3-79 11-54 25.88 54-33 116.3 234.7 564.2 5 .1875 4.00 12. l6 27.29 57.27 122.7 247.4 594-8 6 .2250 4.38 13.31 29.89 62.74 134.4 271.0 651.5 7 .2625 4-73 14-39 32.29 67.79 145.1 292.7 703.6 8 .3000 5-06 15.38 34-52 72.43 155.2 312.9 752.2 9 3375 5-37 16.31 36.6l 76.83 164.6 33L9 797-9 10 3750 5.66 17.19 38.59 80.99 173.5 349-9 841 I ii .4125 5-93 18.03 40.47 84.94 181.9 366.9 882.1 12 4500 6.20 18.74 42.27 88.72 190.1 383.2 921.5 In Tables, T signifies top width ; B, bottom width ; D, depth. 390 GOLD TABLE AND HYDRAULICS TABLE SHOWING FLOW OF WATER THROUGH NOZZLES QUANTITY AND HORSE-POWER. 1 || s'S Diameters of Nozzles. s, tSfc Head ..0 . o 1 >5 3 M 3 i Inch. 1.5 Inches. 2 Inches. 2.5 Inches. Feet. Feet. H.P. 8 w H.P. | Cubic TT T> Cubic Feet. H.P. Cubic Feet. H.P. Cubic Feet. H.P. t 8.025 .106 .212 .041 .0046 .093 .010 .164 .018 -255 .029 1.5 9-83 .158 .316 .050 .0085 .in 019 .200 034 .053 2 "35 .211 .422 .058 .013 .130 .029 .232 052 isto .082 2-5 12.68 .264 .528 .o6 4 .018 145 .041 2 5 6 .072 .402 -.114 3 13.90 3*7 634 .061 .024 159 054 .284 .096 .44 .150 3-5 4 15.01 16.05 370 .421 .740 .842 .016 .081 .030 .03 .068 .083 .304 .324 .120 .148 475 .507 .189 .231 4-5 17.02 474 .948 .086 .044 .194 .099 344 .176 .540 275 17-95 19.66 .528 634 .06 27 .091 .100 .051 .068 205 .224 "3 J 53 364 .400 .204 .272 .56 .622 315 425 7 21.23 739 48 .108 .086 .242 193 432 344 .672 535 7-5 21.98 .702 .III 095 250 .214 444 .380 .697 -595 10 25.38 1.06 .12 .129 .146 .290 .329 .516 584 805 9 T 5 12.5 28.37 1.32 .64 .144 .204 324 .46 566 .816 .897 1.28 15 31.08 3.18 .158 .269 355 .505 632 i. 08 .985 1.68 '7-5 33-57 I'M 3-70 .170 339 .383 .782 .680 1.36 .06 2.11 20 35.89 2.11 4.22 .182 .414 .410 93 1 .728 1.66 .14 2. 5 8 22.5 38.07 2. 3 8 4.76 193 -494 435 1. 11 772 1.98 .21 3-08 25 40.13 2.64 5-28 .204 .578 .458 1.30 .816 2 7 27-5 42.08 43-95 2.00 3-02 5.80 6.04 .213 .228 .660 .760 .480 .513 1.5 1.71 .852 .912 3^S 33 4 a 4.17 4-75 32.5 45-75 3.34 6.68 .232 857 .522 1.93 .928 3-43 45 35 47-47 3.69 7.38 .241 958 542 2.15 964 3-83 5 1 5-t>8 40 50.75 4.22 8-44 257 1.17 579 2.63 .03 4.68 .61 7-3 1 45 53.83 4.75 9.50 .273 1.40 .614 3- I 4 .09 5-6o 7 1 8.23 g 56.75 62.16 5.28 6.34 10.56 12.68 .288 385 1.64 2.15 .648 .709 3-68 4.84 .'26 6.56 8.60 79 97 10.22 13-43 70 80 67.14 71.78 7-39 8.46 14.78 16.90 :! 2.71 3-3 1 .766 .819 6.10 7-45 .36 .46 10.84 I 3- 2 4 13 27 16.93 20.69 90 9-53 19.06 3 86 3-95 .864 8.88 54 15.80 44 24.68 100 80.25 10.56 21.12 .407 4-63 .916 10.41 63 18.52 54 28.90 "5 89-72 13.21 26.42 455 6-47 .02 14-55 .82 25-88 .81 40.40 150 98.28 15-85 3L70 499 8.50 .12 19.12 .00 34.00 3-" S3- 12 175 106. i 18.50 37.00 539 10.70 .21 24.07 .16 42.80 336 66.86 200 "3-5 21.14 42.28 .576 13-1 .29 29-43 3 52.4 3-50 8i.75 250 127.1 26.62 52.84 644 18.3 45 .58 73-2 4.02 114. 300 139.0 3L70 63.40 >75 24.0 59 54-07 .82 96.0 4.40 150. 350 150.1 37.08 74.16 .762 30.3 68.15 3-05 121. 2 4.76 189. 400 450 160.5 170.2 42.27 47.64 84.54 95.28 .814 .864 37-o 44-2 ^83 94 83-25 99-34 3.26 148.0 176.8 5-09 5-40 231. 276. 550 179.4 188.2 52.84 58.22 105.7 116.4 .010 955 59-7 05 .10 116.5 I 34-2 3^6 4 3-82 206.8 238.S 5.60 323- 372.7 600 196.6 63.41 126.8 999 68.0 23 152.9 272.0 6. '23 475-o 700 :2i2. 3 73-98 148.0 i. 06 85-7 46 ,92.8 4-36 342.8 6.79 535-5 800 226.9 84.55 l6g.I i 15 104.7 -58 235-5 4.60 418.8 7.19 654.0 goo 240.7 95.I4 190.3 1.22 124.9 75 281.0 4.88 499.6 7-63 780.5 1000 253-8 105.6 211. 2 1.29 146.2 .89 329-0 5-16 584.8 8.04 914.0 FLOW OF WATER THROUGH NOZZLES 391 TABLE SHOWING FLOW OF WATER THROUGH NOZZLES QUANTITY AND HORSE-POWER (continued.) 8 II II Diameters of Nozzles. Head 1 . H.P. H.P. Cubic Feet. H.P. Cubic Feet. H.P. Cubic Feet. H.P. Cubic Feet. H.P. i 8.025 i. 06 2.12 2.62 .288 3-35 .360 4.07 .46 5-96 .904 1.5 9-83 1.58 3-l6 3-20 544 3-99 .684 4-99 85 7.12 1.68 2 "35 2. II 4.22 3-7* 1 1 32 4.68 1.04 5.76 !! 8.32 2.56 2-5 12.68 2.6 4 5.28 4-08 5-22 1.48 6-44 1.83 9.28 3.58 3 13.90 3-17 6-34 4-56 1-54 5-72 1.94 7-5 2.40 10. 16 4.72 3-5 15-01 3-70 7.40 4-88 1.92 6.16 2-45 7.62 3.03 10.96 5-92 4 16.05 4.21 8. 4 2 5.20 2-37 6.58 2.99 8.14 3.70 n.88 7 24 4-5 17.02 4>74 9.48 5-52 2.81 6.98 3-26 8.64 4.42 12.40 8.64 I 7-95 5.28 10.6 5-84 3-26 7.38 4.07 9.10 5.05 9.92 6 19.66 6-34 12.7 6.40 4.36 8.06 S.Si 9-97 6.80 14.32 *3.32 7 21.23 7-39 14.8 6.92 5-52 8.71 6-95 10.77 8.57 15.48 16.80 7-5 21.98 7.92 15-8 7.12 6.08 9.00 7.70 11.14 9.50 16.00 18.64 10 25.38 10.6 21.2 8.64 9.36 10.41 it. 88 12.87 14.63 i8.n6 28.64 12.5 28.37 13.2 26. 4 9.20 13 84 1.70 16.56 14-39 20.44 20.80 40.08 15 17-5 31-08 33-57 3:! 31-8 37-o 10.12 10.88 17.28 21 .76 2.78 3-77 21.78 28.17 J5.76 26.87 33-86 22'. 7 2 24.48 52.68 67.20 20 35.89 21. 1 42.2 11.64 26.56 4.76 33.48 18.20 41-37 26.24 81.12 22.5 38.07 23.8 47-6 12.36 31 .68 5-66 39.96 I 9>3 1 49-37 27.84 96.80 25 40.13 26. 4 52.8 13.04 36.96 6-47 46.80 20.35 57-82 29.28 "3.3 42.08 29.0 58.0 13-64 42.72 7.28 54-00 21-34 66.70 30.72 130.7 3 43.95 30.2 60.4 14.60 48.64 8-45 61.56 22.81 76.01 32.80 149.0 32.5 35 45.75 47.47 33-4 36.9 66.8 73-8 14.84 I 5-44 54.88 61.28 8.81 9-53 69.48 77.40 23.20 24.08 85.70 95-78 33-44 34-72 168.9 187.4 40 50.75 42.2 84-4 16.48 74-88 20.88 94-68 25-74 117.0 37-12 229.3 45 53.83 47-5 95.o 17.44 89.60 22.14 113.0 27.3 139-6 39.36 273.6 5 56.75 52.8 105.6 18.40 105.0 23-31 128.5 28.78 '63.5 41.44 320.4 60 62.16 63-4 126.8 20.16 137.6 25.56 174.2 31.53 214.9 45-44 421.2 70 67.14 73.9 147.8 21.68 173-4 27.54 219.6 34.06 270.9 48.96 530.8 80 71.78 84.6 169.0 23.36 2TI.8 29.52 268.2 36.41 331.0 52.48 648.8 90 76.13 95-3 190.6 24.64 252.8 3'9-7 38.61 394-9 55.36 774.0 100 80.25 106.6 211. 2 26.08 296.3 32.94 374-8 40.70 462.5 58.56 906.8 125 89.72 132.1 264.2 29.12 414.0 36.72 523.8 45-Si 646.5 65.28 1267 150 98.28 106.1 158.5 185.0 3*7.0 370.0 32.00 34-56 554-o 684.8 40.32 43 56 688.3 866.5 49.85 53.85 849.8 1070 71.68 77-44 1666 2097 200 211.4 422.8 36.80 878.4 46.44 1059 57.56 1308 82.56 2564 250 127.1 264.2 528.4 41.28 1171 52.20 1481 64.36 1828 92.80 3583 300 139.0 317 634.0 45.12 1536 57-24 "947 70.50 2403 101.76 4708 350 150.1 370.8 741.6 48.80 1949 61.56 2453 76.15 3029 109. 594 400 160.5 422.7 845.4 52.16 2368 65.88 2997 81.41 3700 117. 7252 45 170.2 476.4 952.8 55.36 2829 69.84 3577 86.35 4415 124. 8656 500 550 x 79-4 188.2 528.4 582.2 1057 1164 58.24 61.12 3409 3821 73.80 75.60 4194 4831 91.02 95.46 5966 '34- 1003* 11692 600 7 00 800 196.6 212.3 226.9 634.1 739-8 845-5 1268 1480 l6gi 63-84 69.76 73.60 5485 6701 80.28 88.56 92.88 5504 6191 8478 99.71 108.7 115-1 6798 8567 10468 142.7 157-4 165.1 13324 16812 20516 9 00 1000 240.7 253-8 951-4 1056 1903 2112 78.08 82.56 7994 9357 99.00 104.0 10116 11844 122.5 128.7 12489 14624 176.0 185.0 24480 28664 394 GOLD TABLE AND HYDRAULICS EXPLANATION OF PIPE TABLES. The tables for sheet-iron pipe are arranged as follows: COLUMN No. i gives the diameter of the pipe in inches, COLUMN No. 2 is the area in square inches corre- sponding to the diameter. COLUMN No. 3 is the thickness of the iron or steel in decimal parts of an inch. COLUMN No. 4 is the thickness of the iron or steel by the Birmingham wire gauge. COLUMN No. 5 is the working pressure the pipe will be subjected to in pounds per square inch, allowing 10,000 pounds tensile strain per sectional inch of iron, deducting 25 per cent for riveted joints. For steel pipes use 14,000 pounds tensile strain per sectional inch; deduct 25 per cent for riveted joints. Hence, working pressure for steel pipe may be taken 40 per cent higher than given in table. COLUMN No. 6 is the number of cubic feet of water that will flow through the pipe in one minute, when the velocity of the water is 10 feet per second. COLUMN No. 7 is an approximation of the weight of a lineal foot of pipe, including rivets. The cost of pipe varies with the iron market, and the quantity ordered of one diameter and thickness small lots costing sometimes 50 per cent more than large orders. The charge is extra for dipping pipes in asphaltum coating them inside and outside and the cost of dip- ping small pipes is about one cent for each inch in diameter and one foot in length. Coating with asphaltum adds about one third of a pound per square foot to the pipe. P.IPE TABLES 395 d g . & "Sd * 1 JH So K u?rt o o. "o t "o . =1 11-jj a tl V o S'y $ O 5 *3. w * 1 rt C Q * ^ 3 tfi k X ^ 4> s .2 4) u 13 1* = isis. .s.s Q H P u ^ 1 2 3 4 5 6 7 3 3 7 7 0.035 0.049 20 18 I 7 6 245 2 9 29 3 4 12.5 0.049 18 183 52 3 4 12.5 0.065 16 243 52 4 5 19.6 0.049 18 147 81 3ir 5 19.6 0.065 16 195 81 5 5 19.6 0.083 14 249 81 6; 5 19.6 o. 109 12 327 81 8, 6 28 049 18 122 116 4- 6 28 .065 16 162 116 5: 6 28 .083 14 207 116 7- 6 28 .109 12 272 116 10 7 38 .049 18 105 158 Si 7 38 .065 16 141 158 6: 7 38 093 14 I 7 8 158 8 ; 7 38 .109 12 234 158 II- 8 50 .065 16 119 208 J- 8 50 .083 14 555 208 9. 8 50 .109 12 204 208 13 8 50 .120 11 225 208 14 8 50 134 10 252 208 X 5; 9 63 .065 16 1 08 262 8, 9 63 .083 14 138 262 IO ; 9 63 .109 12 182 14; 9 63 .120 II 200 262 16 9 63 134 IO 228 262 17- IO 78 .065 16 98 313 9; 10 78 083 '4 125 313 11^ 10 78 .109 12 164 313 15- IO 78 .120 II 313 17 10 78 134 10 201 313 19^ II 95 .065 16 8 9 378 9; II 95 .083 14 "3 378 13 II 95 .109 12 149 378 J 7i II 95 .120 II 162 378 1 8} II 95 134 10 183 378 21 12 "3 .065 16 81 470 IIj 12 H3 .083 14 104 470 14 12 .109 12 136 470 1 84 GOLD TABLE AND HYDRAULICS 1 | h O rt in v ** 5-S >>S *- I "o g V II 3 IB s 5 !! || 5 1 S~ P u p i 2 3 4 5 6 7 16 201 .180 7 169 837 4i 16 201 .203 6 I 9 837 481 16 201 .238 4 223 837 54 18 254 .065 16 54 1058 16 18 254 .083 14 69 1058 20 18 254 .109 12 1058 27 18 254 .120 II 100 1058 30 18 254 134 IO in 1058 34 18 254 .I6 5 8 138 1058 41 18 254 .180 7 150 1058 46 18 254 .203 6 169 1058 I 18 254 .238 4 198 1058 60' 20 314 .065 16 49 1308 18 20 314 .083 14 63 1308 as \ 20 314 .109 12 82 1308 30 20 314 .120 II 90 1308 32, 20 314 134 10 101 1308 36, 20 .I6 5 8 124 1308 44^ 20 314 .180 7 135 1308 50- 20 314 .203 6 153 1308 56- 20 3H .238 4 179 1308 66 22 380 .065 16 45 1583 20 22 380 .083 14 57 1583 24 r 22 380 .109 12 75 1583 32- i 22 380 .120 ii 82 1583 35| 22 380 134 IO gi 1583 40 22 3 80 .165 8 112 1583 48- l 22 380 .ISO 7 123 1583 51 22 380 .203 6 138 1583 62 22 380 .238 4 162 1583 72 24 452 .083 14 52 1883 27- i 24 452 .109 12 68 1883 35i 1 24 452 .120 II 75 1883 39 24 452 134 10 84 1883 43* 24 452 .165 8 103 1883 53 24 452 .l8o 7 112 1883 60 24 24 26 452 452 530 .203 .238 .083 6 4 14 127 149 48 1883 1883 2208 671 3 398 GOLD TABLE AND HYDRAULICS 1 G g. & E rt _,' la's I 3 rt M Q. * *o s "o . ^o ! O *j*o "O jj 1017 134 10 56 4236 67 36 1017 .165 8 69 4236 78 36 1017 .ISO 7 75 4236 88 36 1017 .203 6 84 4236 98 36 1017 .238 4 92 4236 114 36 1017 .250 * 104 4236 120 PIPE TABLES 399 i c If | a rtj I U-l **-i CTJ 3 O.J S. O . oo Q-o* U * J< O "O O S e| a rt -a c >, ~te c v% JJ - u "o a c $ 3" Co si S rt s S 1-S Ifr r P U bt.O 1 2 3 4 5 6 7 36 1017 259 3 108 4236 125 36 36 1017 1017 3125 375 (* 130 156 4236 4236 153 1 86 40 1256 134 10 51 5232 71 40 1256 .165 8 62 5232 86 40 1256 .180 7 68 5232 97 40 1256 .203 6 76 5232 108 40 1256 .238 4 90 5232 126 40 1256 .250 i 94 5232 132 40 1256 259 3 97 5232 138 40 1256 3125 A 117 5232 169 40 1256 375 I 141 5232 205 42 1385 134 10 48 5769 74* 42 1385 .165 8 59 5769 91 42 1385 .180 7 64 5769 102 42 1385 .203 6 72 5769 114 42 1385 .238 4 85 5769 133 42 1385 .250 i 89 5769 137 42 1385 259 3 92 5769 145 42 1385 .3125 T 6 * in 5769 177 42 1385 375 1 134 5769 216 44 1520 134 10 45 6332 78 44 1520 .165 8 56 6332 95 44 1520 .180 7 61 6332 1 06 44 1520 .203 6 - 69 6332 119 44 1520 .238 4 81 6332 139 44 1520 .250 ^ 85 6332 145 44 1520 .259 3 88 6332 151 44 1520 .3125 T7T 1 06 6332 185 44 1520 375 J. 128 6332 225 48 1809 134 10 42 7536 85 48 1809 .165 8 51 7536 103 48 1809 .180 7 56 7536 116 48 1809 .203 6 63 7536 130 48 1809 238 4 75 7536 151 48 1809 .250 i 78 7536 158 48 1809 259 3 81 7536 164 48 1809 A 98 7536 210 48 1809 375 1 117 7536 245 400 GOLD TABLE AND HYDRAULICS FLOW OF WATER THROUGH RECTANGULAR ORIFICES IN THIN VERTICAL PARTITIONS. Question: The head being 10 feet, and the gate- opening being 6 inches high and i foot wide, what will be the discharge in miner's inches ? Answer: In this table, opposite lofeet in first column, find in column headed 6 Inches High, i Foot Wide, 7.62 cubic feet. Multiply this number by 50, the number of miner's inches in i cubic foot, and there results 762 X 50 = 381.00 miner's inches. Question: The head being 25 feet and the opening i T 8 u- inches high, i foot wide, how many pounds will be discharged per second ? Answer: In this table, opposite 25 feet in first column, find in column headed 1.5 Inches High, i Foot Wide, 3.05 cubic feet. Multiply this number by 62.5, the num- ber of pounds in a cubic foot. 3.05 X 62.5 = 190.625 pounds. Question: The head being 7 feet and the opening i inch high, i foot wide, what will be the discharge in cubic feet ? Answer: In this table, opposite 7 feet in first column, find in column headed 3 Inches High, i Foot Wide, 3.24 cubic feet. The given height i inch is one-third of 3 inches, the height of the opening; hence, without sen- sible error, we may take one-third the flow due 3 inches for that opening. 3.24 *- 3 = 1.08. FLOW OF WATER 401 TABLE SHOWING FLOW OF WATER THROUGH REC- TANGULAR ORIFICES IN THIN VERTICAL PARTITIONS. u 8 Breadth and Height of Orifice. 8 >> o i ft. High, i ft. Wide. 9 in. High, i ft. Wide. 6 in. High, i ft. Wide. 3 in. High, i ft. Wide. 1.5 in. High, i ft. Wide. 2 5 Feet. Feet. Cubic Feet. H.P. Cubic Feet. H.P. Cubic Feet. H.P. Cubic Feet. HP. Cubic Feet. H.P. .028 O. 2 3- 5 o . 69 .022 4 3 4.4 jjk .80 40 .018 .4 5-7 2 c*7 .146 5 U . 74 099 .89 .O5I 5 .6 6^22 3-72 253 2.83 .193 91 .130 .066 49 033 .7 6.72 4.02 .317 3.06 .249 .07 .165 '.06 .082 53 .041 .8 6.38 4-3i 392 3-27 .297 .21 .201 14 ,104 57 .052 9 7.62 4-57 .467 3.48 .356 35 .240 .20 .122 .60 .061 I.O 8.025 4-87 554 3.67 .417 -48 .281 .26 .144 .63 .072 1.25 8-99 5-29 751 4.02 571 .385 39 .197 .69 .008 1.50 9.83 5-92 .01 4-50 .767 3-03 517 55 .259 77 .129 1.75 10-59 6. .40 .27 4.86 .967 3-27 .650 .67 .326 83 .163 2.00 11-35 6.85 56 5-20 .18 3-50 795 79 .398 .89 .199 2.25 12. OO 7.27 .86 5-51 41 3-71 949 -89 475 95 237 2.50 12.68 7.67 .18 5-8i .65 3-91 I. ii -99 .565 I. 00 .283 2-75 3-oo 13-32 13.90 8.05 8.41 53 6.09 .86 4.10 4.27 1.28 1.46 :3 654 743 1.04 1.09 327 371 3- SO 15.01 9.08 3^6i 6^se 73 4.61 1-83 35 -935 1.17 .467 4.00 16.65 9-97 4-54 7-32 3-33 4.92 2.24 -50 I-I4 1-25 568 4-50 17.02 10.29 5-26 7-75 3.96 5-21 2.66 1.36 1.32 .678 5.00 17-95 10.84 6.16 8.16 4-64 5-49 3-12 7^ 1.58 1-39 .781 6 19.66 11.84 8.08 8.91 6.08 5-98 4.08 3-03 2.07 LSI 1.03 7 21.23 12.76 10. 14 9.61 7-64 6-43 5.12 3- 24 2.58 1.62 1.29 8 22.71 13-64 12.40 10.25 9-32 6.84 6.22 3-45 3-14 1.71 1.50 9 24.70 14.47 14.80 10.86 ii. ii 7-25 7.42 3-64 3-72 1.83 1.82 10 25-38 15-25 17-34 n-44 13.00 7.62 8.66 3-83 4-34 1.92 2.18 IS 31.08 18.68 31-85 14.01 23.88 9-34 15-93 4-69 8.00 2.36 4.02 20 35-89 21.50 49-05 16.18 36.78 10.8 24-55 5.42 12. 29 2.72 6.15 25 40.13 24.12 68.52 18.10 51-42 12.08 34-32 6.06 17.22 3-05 8.67 30 43-95 26.43 00. IO 19.84 67.64 13-47 4^.92 6.64 22.64 3-35 11.42 35 47-47 28.55 113.6 21.44 85.27 14-31 <;6.o6 7.18 28.56 3-62 14-40 40 50.75 30-53 138.8 22.94 104.3 15.32 69.64 7.68 34-91 3-79 17-23 45 50 53.83 56.75 32-39 34-15 165.6 194.0 24-35 25.68 124.5 145.8 16.26 17.16 83.14 97-50 8.16 8.61 41-73 48.92 4.12 4-35 21.02 24.72 402 GOLD TABLE AND HYDRAULICS VOLUMES OF WATER REQUIRED FOR EFFECTIVE USE IN OPERATING HYDRAULIC GIANTS. 2 -Inch 2^-Inch 3-Inch 4-Inch 5 -Inch Head. Nozzle. Nozzle. Nozzle. Nozzle. Nozzle. Feet. Miner's Miner's Miner's Miner's Miner's Inches. Inches. Inches. Inches. Inches. 100 80 125 185 325 500 15 IOO 155 225 400 625 200 H5 180 260 460 7i5 250 130 200 290 5iS 800 300 140 220 . 320 565 880 35 ISO 24O 345 610 950 400 160 255 365 650 1000 The area of circles in square feet may be obtained from the following table, which is also the number of cubic feet in i foot length of the pipe. (Trautwine.) Diameter. Inches. Area. Sq. Feet. Diameter. Inches. Area. Sq. Feet. Diameter Inches. Area. Sq. Feet. I .0003 3i .0576 gj .2131 1 .0014 3i !o668 fil .2304 J .0031 3l .0767 6f .2485 r 55 4 .0873 7 .2673 if .0085 4i .0985 71 .2867 {1 .0123 4i . 1104 7i .3068 if .0167 4l .1231 7t .3276 2 .0218 5 1363 8 3491 2 f .0276 Si 8J .3712 2 I .0341 5f .1650 8} 3941 2 f .0412 Si 1803 8| .4176 3 .0491 6 .1964 9 .4418 To Find the Square Root of a Number: Separate the given number into periods of two each, beginning at unit's place, thus: 18, 66, 24; or if the number be a deci- FLOW OF WATER 403 mal fraction, work both right and left from unit's place, thus: i, 96, 13, 69. Find the greatest number whose square will go into the first period, and subtract this square; to the remain- der annex the next period. Divide this new dividend by twice the square root already found, multiplied by 10 for a trial divisor. The quotient thus found add to the trial divisor; it is the next figure of the root. Multiply this divisor by the last root figure and subtract as in the first instance, etc. Example. Find the square root of 186624. 18, 66, 24(432 4X4= 16 4X2= 8 X 10 = 80 + 3 = 83) 266 83 X 3 = 249 80 + 3 X 2 = 86 X 10 = 860 + 2 = 862 1724 862 X 2 = 1724 Example. Find the square root^of 58.140625. 58. 14 06 25 \j.fa$Ans. 49 7X2 = 14X10 = 140+6=146 914 146 X 6 = 876 140 .3806 12 = 6X2 152 X 10 = 1520 + 2 = 1522 1522 X 2 = 3044 1520 7 622 5 4=2X2 1524 X 10 = 15240 + 5 = 15245 15245 X 5 = 76225 Example. Find the square root of 196.1369. Answer. 14.0048+. 404 "GOLD TABLE AND HYDRAULICS TABLE OF SAFE HEAD FOR RIVETED HYDRAULIC PIPE. SHOWING PRICE AND WEIGHT WITH SAFE HEAD FOR VARIOUS SIZES OF DOUBLE-RIVETED PIPE. Cub. Ft. Diameter of Pipe in Inches. Area of Pipe in Inches. Thickness of Iron by Wire Gauge. Head in Feet the Pipe will safely stand. of Water Pipe will convey per min. at Vel. Weight Lineal Foot in Lbs. Price per Foot. 3 f t. Per second. 3 7 IS 4OO 9 2 $0.20 4 12 18 350 16 H 25 4 12 16 525 16 3 35 5 5 20 20 18 16 325 500 25 25 ll 35 45 5 20 14 675 25 5 50 6 28 18 296 36 4 J .44 6 28 16 487 36 5- 50 6 28 14 743 36 7^ .56 7 38 18 254 50 5 50 7 38 16 419 50 6; .56 7 38 14 640 50 8, .63 8 50 16 367 63 7- 65 8 50 14 560 63 9i 75 8 50 12 854 63 13 94 9 63 16 327 80 8 .69 9 63 14 499 80 10 .88 9 63 12 761 80 M 1.06 10 78 16 295 100 9: .72 10 78 14 450 100 II: .82 10 78 12 687 100 15- 1. 00 10 78 II 754 IOO *7i 1.25 10 78 10 900 100 J 93 1.50 ii 95 16 269 1 20 9l 75 ii 95 14 412 120 13 94 ii ii 95 95 12 II 626 687 120 120 iTt i8f 1-25 1.44 ii 95 10 820 120 21 1.62 12 H3 16 246 142 Hi .82 12 H3 14 377 142 14 1. 00 12 H3 12 574 142 lS4 1.38 12 113 II 630 142 I9f 1.50 12 H3 10 753 142 22f 1.69 I SAFE HEAD FOR RIVETED HYDRAULIC PIPE 405 SAFE HEAD FOR RIVETED HYDRAULIC PIPE. (Continued.) Diameter oi Pipe in . Inches. Area of Pipe in Inches, Thickness of Iron by Wire Gauge. Head in Feet the Pipe will safely stand. Cub. Ft. of Water Pipe will convey per min. at Vel. 3 ft. per second. Weight Lineal Foot in Lbs. Price per Foot. 13 132 16 228 170 12 $0.90 13 132 14 348 170 15 1. 12 13 132 12 530 170 20 1-50 13 132 II 583 170 22 1.6 5 13 I 3 2 10 696 170 24* 1. 80 14 rs3 16 211 200 13 .98 14 153 14 324 2OO 16 I.I7 14 153 12 494 2OO 2I] 1.57 14 153 II 543 200 23* 1.72 14 153 10 648 200 26 1-95 15 176 16 197 225 13! .96 15 176 14 302 225 17 1.28 15 176 12 460 225 23 1-75 15 176 II 507 22 5 24* 1-95 15 176 10 606 225 28 2.10 16 201 16 185 255 '4i 1.05 16 201 14 283 255 J 7; 1.20 16 201 12 432 255 24; 1.70 16 2O I II 474 255 26i 1.85 16 201 10 567 255 291 2.00 18 254 16 165 ' 320 i6j 1.20 18 254 14 252 320 2Oi I.4O 18 254 12 385 320 27; I. 9 18 254 II 424 320 30 2.IO 18 254 IO 505 320 34 2.40 20 3M 16 148 ' 400 18 1.26 20 14 227 400 22^ 1-54 20 314 12 346 400 30 2.IO 20 314 II 380 400 3 2 i 2.25 20 314 10 456 400 s4 2.5O 22 380 16 135 480 20 I.4O 22 22 22 380 380 380 14 12 II 206 316 347 480 480 480 a 351 1.70 2.25 2-45 22 380 IO 415 480 40 2.80 24 24 452 452 14 12 188 290 570 570 7f 35* 1.80 2.35 24 452 II 318 570 39 2.70 24 452 10 379 570 2.95 24 452 8 466 570 53 3-50 406 GOLD TABLE AND HYDRAULICS SAFE HEAD FOR RIVETED HYDRAULIC PIPE. (Continued.} Diameter of Pipe in Inches. Area of Pipe in Inches. Thickness of Iron by Wire Gauge. Head in Feet the Pipe will safely stand. Cub. Ft. of Water Pipe will convey per min: at Vel. 3 ft. per second. Weight per Lineal Foot in Lbs. Price per Foot. , 26 530 14 175 670 29i f 2.OO 26 530 12 267 670 3 8 i 2-59 26 530 II 2Q4 670 42 2.87 26 530 10 352 670 47 3.10 26 530 8 432 670 57i 3.85 28 615 14 102 775 3'i 2.12 28 615 12 247 775 4l| 2.75 28 615 II 273 775 45 3.00 28 28 6'5 615 IO 8 327 400 775 775 1 3-20 4-15 30 706 12 231 890 44 2.90 30 706 II 254 8qO 48 3-15 30 706 10 304 890 54 3-50 30 706 8 375 890 65 4.30 30 706 7 425 890 74 4.75 36 1017 ii 141 1300 58 3.80 36 1017 10 155 1300 67 4-30 36 1017 8 192 1300 78 5.10 36 1017 7 210 1300 88 5.75 40 1256 IO 141 1600 7i 4.75 40 1256 8 174 1600 86 5.60 40 1256 7 I8 9 1600 97 6.40 40 1256 6 213 1600 108 7-35 40 1256 4 25O 1600 126 8.50 42 1385 10 135 1760 74^ 5-05 42 1385 8 165 1760 9i 6. 20 42 1385 7 1 80 1760 102 7.00 42 1385 6 210 1760 114 7.80 42 1385 4 24O 1760 133 9.00 42 1385 * 27O 1760 137 9-50 42 1385 3 300 1760 145 10.00 42 1385 T 6 * 321 1760 177 12.00 42 1385 f 363 1760 216 15.00 NOTE. Where formed and punched including rivets, for mule packing or to facilitate transportation by other means, 30 per cent may be deducted from prices above given. This list is based upon pipe coated inside and out with asphaltum, and is given for the purpose of enabling parties to make an approximate estimate of the cost. Net prices will be quoted on application. TABLE OF VELOCITIES TABLE OF VELOCITIES. 407 a 'a 1 a ,o fj Discharge per Second through Nozzles. c 'i <- > * 1 15 it .' / j rC 1 Z i 10 25.4 26.32 11.18 44-30 99-78 177.4 277.0 399.1 682.2 709.4 2O 35 9 28.72 15-79 62.61 141.0 250.8 39 r -4 564.1 767.7 1026 30 43-9 35-12 19.32 76.56 173-9 306.6 478.7 689.7 938.8 1226 40 5-7 40.56 22.31 89.24 199-3 354-1 552.8 796.7 1085 1416 5 56.7 45-36 24-95 98.88 222.7 396-0 618.4 890.9 1213 1584 60 62.! 49.68 27.33 108.30 243-9 433-7 677.1 975-7 1328 70 67.1 53.68 29-52 117.01 263-5 468.6 731-7 1053 1435 1874 80 71.8 57-44 31.66 125.24 282.0 SOLS 783.9 1129 1535 2005 90 76.1 60.88 33-49 132.87 298.9 531-4 829.8 1196 1627 2126 100 80.3 64.24 35-33 140.32 308.9 560.8 874-6 1262 1717 2243 no 84.2 67-36 37.05 146.82 ^30.8 588.0 918.1 X 3 2 3 1801 2352 120 87.96 70.36 38.70 153-48 345-5 614.3 959-0 1382 1881 2456 130 91-54 73.23 40.28 I59-92 359-5 630 3 998.1 1439 1958 2556 140 94.99 75-99 41.80 J 65-73 37|.i 663,4 1036 M93 2031 2653 *5O 98.3 78.64 43.26 I 7 I 54 386.1 686 5 1072 1545 2IO2 2745 1 60 101.49 81.19 177.26 398.5 708.8 1107 1595 2170 2834 170 104.56 83.62 45.99 182.36 410.5 718.4 1140 1643 2236 2919 180 107.76 86.20 47-41 188.16 423.2 752.5 1176 1693 2305 3009 190 110.65 88.52 48.69 192.92 434-7 772.8 1207 ^739 2366 3091 200 "3-54 90.83 49-94 198.16 446.0 793- 1238 1784 2428 210 220 116.35 119.08 93.08 95.26 51-20 52.49 203 . 80 207 . 82 457-0 467-8 812.6 831-7 "59 1299 1828 1872 2 4 88 2547 3250 3326 2 3 121.73 97.38 53.56 212.33 478.1 850.1 1323 19*3 2604 240 124 99-2 54-56 216.2 487.0 866.0 1352 1948 2652 3463 250 126 100.8 55-44 219.8 495-0 888.0 1374 1980 2694 260 129 103.2 56-76 225.0 560.7 900.9 1407 2027 2759 3603 2/0 104.8 57.64 228.5 514.6 914.9 1428 2059 2801 3649 280 J 34 107.2 58.96 233-7 526.3 935-9 1461 2105 2865 3742 290 136 108.8 59.84 237.7 534-1 949-9 1483 2127 2909 3798 300 3 IO 320 139 141 143 in. a 112.8 114.4 60.32 61.64 62.92 239.1 240-3 249.4 538.8 541-2 561.7 957-5 962.3 998.8 1503 2154 2165 2246 2932 2947 3058 3819 3835 3993 33 34C MS 148 IIO.O 1,8.4 63.80 64.61 252-9 256.1 569-6 576.8 1012 1025 Jfp 1601 2278 2307 3IOO 3*4 4050 4101 35 120.0 66.00 261.6 589-2 1047 1635 2357 3207 4189 360 152 121. 6 66.88 262.5 597-1 1062 1658 2388 3245 4245 370 380 156 123.2 124.8 67.76 68.64 265.1 272.1 604.9 612.8 1075 1090 1679 1701 2419 2449 3293 3336 4301 4358 390 158 126.4 69.52 275.6 620.6 IIO4 1723 2482 342 44" 400 160 128.0 70.40 279.0 628.5 III7 1746 25U 3422 4468 410 162 129.6 71.28 282.5 636.3 H32 1767 2545 3462 4523 420 43 \66 I3I.2 132-8 72.11 73-04 285.8 289.5 643-7 652.0 1 144 1160 1787 1790 22 3505 3539 SB 440 45 168 170 134.4 136.0 73.92 74.80 293.0 296-4 659.9 667.8 "74 1188 1832 1854 2640 2672 3593 3635 4692 4747 408 GOLD TABLE AND HYDRAULICS TABLE FOR WEIR MEASUREMENT, GIVING CUBIC FEET OF WATER PER MINUTE THAT WILL FLOW OVER A WEIR I INCH WIDE AND FROM ^ TO 2oJ INCHES DEEP. Inches. M J4 % ^ % H % .00 .01 .05 .09 .14 .19 .26 32 I .40 47 55 .64 73 .82 .92 1.02 2 1. 13 1.23 1-35 1.46 1.58 1.70 1.82 1-95 3 2.07 2.21 2.34 2.48 2.61 2.76 2.90 3-05 4 3.20 3-35 3.50 3-66 3.8i 3.97 4.14 4.30 5 4-47 4.64 3.8i 4.98 5.15 5.33 5.5i 5.69 6 5.87 6.06 6.25 6.44 6.62 6.82 7.01 7.21 7 7.40 7.60 7.80 8.01 8.21 8.42 8.63 8.83 8 9-05 9.26 9-47 9.69 9.91 10.13 10.35 10-57 9 10.80 II. O2 11.25 11.48 11.71 11.94 12.17 12.41 10 12.64 12.88 13-12 13.36 13.60 13.85 14.09 14-34 ii 14-59 14.84 15.09 15-34 15.59 15-85 l6.TI 16.36 12 16.62 16.88 17.15 17.41 17.67 17.94 18.21 18.47 13 18.74 19.01 19.29 19.56 19.84 20. II 20.39 2O.67 14 20.95 21.23 21.51 21.80 22.08 22.37 22.65 22.94 15 23.23 23.52 23.82 24.11 24.40 24.70 25.00 25.30 16 25.60 25.90 26.20 26.50 26.80 27.11 27.42 27.72 17 28.03 28.34 28.65 28.97 29.28 29.59 29.91 30.22 18 30.54 30.86 31.18 31.50 31.82 32.15 32.47 32.80 19 33-12 33-45 33.78 34-n 34.44 34.77 35.10 35.44 20 35-77 36.11 36.45 36.78 37.12 37.46 37.80 38.15 LOSS OF HEAD IN PIPE BY FRICTION 409 O J3 4-1 bC c JV 525 "c o 7; H S - PI S|l K*H .2 S a, |S J5 S ^^s 2]1 S^g. t o s| SJSS s;-? * %> S ^s ;l C en kJS O C !! H& a 3*1 ?nAfta i **&m'M8M co O *O 41 Il Ht^. M o >n m M M + ri*i a M - M rO>O^C>MNO O I/IM t^roO t^ M mvO txOO M (N rr, ^-vo t^ ON O .oo o> o c* to -^- i/i\o t^oo o^ o ^ ^o 111 ^S| s -^^ ? ^-^-- J .S .jj-| sw^gsgsft&as&a&asiu CO u<- III ON PO QNNO ^- N N -^-VO O^ fOOO IT) CO M M M f^vo O ^ N t~ O> O N -* N OOO M * |v O * t*OM t->(V) O\VO W 00 * O VQ N OO >OVO VC 00 H 3-VO ON HI ^-r^ONM K 8 M "10 O f> "100 M fM ufe s. Ill *i?BSS8MfttMSM9 3 K .s M |S'I *BBIJ.OTSgjm5*MUff8*R c>fc *slj S5 S- < RS,^5g-^8 SMSRJg'S t!T5- S5 w^ ro w > in\o t*oo oo ON - cp j- m -S 6 < K< !*' o N t vooo o (. r oo o t vooo o ? o q >" " fc a W N N ro 410 GOLD TABLE AND HYDRAULICS o c '** S:?^S fUS^SSKS %&" XZZZ& 5*1 ill CO * trim Q txtxO^O -*OOMOro -*oo * m O^f^^M^O O lOHVO NOO -^-i-tOO ICO OOOVO -^-f^M 3 ffi .s o^.S IS U S MHO ** t^OO C^OwwPlfOrt-10 10^ t^OO OO^OMNWrn^ _ w*l Hi \O lOtx^-N ^-Ot^t^O I^VO OO ro O N M lOO-^O^O-lOMOO -<*-wOOVO < OOO ^^O VO tN N W N f*l m * * ITHO VO txOO OOO>O>-i(N-O .3=5 o.S ^*? * 1O H VO N >AodioooOMOoi*-i-i t^^o r^rio t^novoo >O t^ voo o\OO M IH roro^-io io>o t~- t^oo o> o< o s. "o-o Jed D wrT tx M txOO MOO ON OON txtxOlrt COOO W t^ fOOO "^M t^'fJ-N O^t^lO^fON H M M WOO N N ff. m -n- * mvo vo tvoo oo o> o M *? rooo woo *-o\-*O "iM\o H>O M r>woo rooo * o m 10 iO\0 vo tx .00 0>t>00"'-.Pir<1fO-*-*->0 1000 o> ^| 0> 2 S ^d ioO O + O\ O iO>* COOO vO f^ VO HVO (NOO --OOO 10 ro w OiOO t^ t> t^ v t^OO OWN 5*3 12? H VO O -*00 N tXM toorotxpivo Q lOOvfOt^M IOVO ^ ^- 10 10 >ovo vo t^ r-. t^oo OOIXTIOOOMMNW-^- 00 <>S o-a a> 8S VO M O f> O M VO 1000 VO tV N OlOM tv-^MOOVO -^-CON N N M fO^lOt^Ovw 1O1O N m * + iovo vo t>.oo o> O M N ro TJ- iovo t^oo O H oo 53 ss C4 1OOO M ^-OO w ^- fx O ** tx O C^VO O fOVO O fOVO N ""s. o-a *J 8S 00 M OO O t^OO 1O 1O O\ O 1O ro O vo * O^CO t^vo t^ I^OO Ov H rovO O> fO ^ M vo vo CO i-^- IOVO VO t>.00 ON M < D$ fe > PQ M cu t-H cu z -^ Q < M ffi fe o % 3 3 si ~ .S o mvo >roo O> O ^t" ONVO ""> o mo v '-"1O t^\O \O O> (N 00 fell >-^ I^NvO M\O H tOO IOO ^O^'Ov mOO CO t^ N tx N 1O ^VO fri Ov 3 m tovo 00 ON IN rf. iovO OO O- M N ,f MM MM N N WIN O OO N OO t^OO r^M 00 00 3:5 o ^ 2 s gyajg ^s 8 a f SHHf Sa&S o M -*vo oo o PI *vo oo q w fvo oo o N -*-vo woo N w ci fi -ntncnmrO'T'i-'*-*'*''* 1 ^"^ 1 ^ n>o i^ 412 GOLD TABLE AND HYDRAULICS ! 55 O > i u 2 fa o_2 a "o S 4- ro M o oo Cx 10 - N M ooo vo 10 m N o O t^vS ^JS OOOO'-'MNrO'* iovo vo t^oo O O M N w r<1^5- iooo J G "f ufe a .1 a s Ill VO 00 w * O 10 N OOO t-00 OM rfOQ N 00 * M O OVO Hi J B .S jii | r sl oco t^vo * fOOO NVO "">O s 'ror*-.WVO O ^*OfO tx.OO ^OO fO tx H VO O lO O ^-00 N tx M VO O lO O fOOO N -<* ^f ^- 10 iovo vo t^ tx tCoo oo c^ o o o M MM 5a co 10 S 4J ^ o u' T 'b 1" o % n o-a M OO NO IO IOOO w IOCO lO^OlOt^O "**O V O fON N O\ C> O W ^"^0 oo M rovo oo M ^r^o ^tvM ^-oo o vo t%. -IH g o & J ffi .S S 3 o II y ^.S tN.^-W OCO lOrOiHOOVO ^*-M O^iON OOO lOfOM & r^-> IOC^NVO o ^ t^^ o o> w vo o ^-oo M 10 o\ m M ro ^ -4- ^ to iov5 \0 vo tx tx txoo oo O\ 5 ON ro *^1 ^ -o I " *> - ioo\rot>.)H 10 5HM t-i H N w N w rororO'Tf^-^t-ioio iovo vo t% o\ o -g .2 -a ^ K .s 1 '? t-l (S -2--S ^O 00 O W fO IO t*sOO O M fO 10 t^OQ O N CO 1O t^.00 O O\ M ^-06 M ^ t^ O CO t^ rov0 OS N vo OA W IOOO M IO O fororo^^*^ > io>o *ovo vo vo vo tx tN, t^-oo oo oo ^ o^ M D C *"* > a 4 v ||| laSS-sgfHSSlHR^^Stl 3 1 * M ^ "2 .a 1II H 1 V 1? o -*vo oo q M * oo o N ^-vo oo o N ^vo oo o o *"=' -* a VO INDEX PAGE Absorption and evaporation no, 153 Acceleration of gravity 87 Air valves 187 Alaska mining 24 Altar, Mexico, dry placers 17 Amalgam 67 Amalgam kettles 235 Ancient rivers 2, 9, 15 Apex law 33 6 Area of circles 4 2 of sluices 85 Asphalt paint 175 Assaying 25, 64 Assessment work 335, 342, 345 Atlin, B. C 240, 256 Attwood, Melville, Gold Table 368 Barr, J. A 247 Batea 65 Bazin ditch formula 98 Bed-rock sluices 75 Black sand 3*4 Black sand experiments 322 Black sand in Caribou 267 Black sand, platinum in 9 Blankets in sluices 71, 290 Blasting charge 243 Blasting dredging ground 276 Blasting explosives . 242 Blasting gravel banks 241 413 414 INDEX PAGE Booming 57 Bowie, Alex. J., on pipes 174 on riffles 140 on storage reservoirs 153 on water duty 228 Bowman reservoir 153 Breckenridge, Col 5, 150 Brine pumping 54 Bucket capacity 276 Bucyrus 276 chains 276 construction 275 dredge 270 excavators 275 Knight 260 ladders 273 speed 275 Cabin John, Md 5 Cable towers 258 Cableway 258 Calculating placer ground 23 California Gulch, Colo 5 Caminette Act 16, 206 Cape Nome, Alaska . 3 Caribou black sands 267 Centrifugal pumps '. 247, 283, 294 Chains, bucket 276 Chezy formula 96, 98 Claims, recording 339,341 size of, in Canada 353 size of , in U. S 343,3^4 Cleaning bed rock 233 Clean-up 232 Cliff flumes 163 Coefficient of pipe entrance 381 of roughness 98 Comstock lode, Nev 6 Construction of hull 270 INDEX 415 PAGE Cost of dredges , 262 of dredging 269 of elevating 217, 202 of hydraulicking 298 Coxe-Weisbach formula, pipes 181 Cradle or rocker 66, 246 Craig, R. R., stovepipe 174 Crib dams 156 Culm pile mining 59 Dams 155 Dams, debris 155 Day, Dr., black sand experiments 325 Development of placer mining 61 Dipper dredge 277 power for 308 Disadvantages of buckets 277 Ditches, carrying capacity 383 depth of flow 203 flow of water in 194, 200 form for 196, 383 safe velocity in 108, 194, 201, 207 side slope for 201 size of 198 table 388 Ditch lines 190 surveys 190 Dixon's method of valuation 39 Docoto's method of valuation 36 Dredges, cost of 269 dipper 277 power for 293 selection of 265 suction 282 traction 297 Dredging, cost of 268 river bars 264 Drifting 42 Drift mining 237, 247 416 INDEX PAGE Drift removed by water 222, 228 Dry placers 7, 17 Dry-placer mining machines 18, 297, 310 Dubuat formula, ditches 207 Dumping ground 148 Duty of elevators 219 of giants 224 of miner's inch 225 of water 96 Dynamite 242 Edith mine, N. C 250 Edward Edwards n Elevator, Campbell's 221 Ludlum's 221 Elevators at Breckenridge, Col 221 at Feather River, Cal 220 cost of working 217,221 duty of 216 hydraulic 214 Empire drill . 34, 45 Estimating placers 24, 28 Evans elevator 214 Excavators for dredges 273 Explosives 242 Exploiting 227 Eytelwein's formula, ditches 206 Filling pipes 190 Flow of water through channels (tables) 200, 387 nozzles (tables) 384 orifices (tables) 401 pipes (tables) 179, 374 velocity of 87 Flume construction 163 carrying capacity 163 curves 167 waste gates 171 Formulas: Bazin, on ditches 98 INDEX 417 PAGE Formulas: Chezy, on ditches 96 on pipes 116 Coxe-Weisbach, on pipes 181 Dubuat, on ditches 207 Eytelwein, on ditches 206 Francis, on weirs 172 Kutter, on ditches 98 Leslie, on ditches 96 Poncelot, on ditches 206 on pipes 206 Rankin, on pipes 182 Smith, on pipes 172, 181, 206 Weisbach, on pipes 181 Free miner's certificate 349 Fresno power plant 176 Frictional resistance 180 in ditches 167, 194 Friction in pipe 125, 180 pipe bends 181 sluices 167, 194 Gantry 273 Gates, water 185 Geology of placers i Georgia 246 dredging 281 Giant 210 Giant, spouting velocity of 211 water measurements from 221 Gilchrist, A. D 171 Gold and talc 145 float 58, 144 flour 9, 137 impurities in 25 leaf . 9, 58 movement in ditches 280 nuggets 15 saving arrangements 252, 288 table . 368 418 INDEX PAGE Golden Feather River 220 Grade for ditches 206 flumes (table) 207 sluices 194 Graphical hydraulics 98 Ground sluices . . . . 75 Gulch mining 7 Hafer, Claude 246 Head, loss of (table) 180, 409 Head of water 179 Heinrich, O. J 56 Herschel, Clemens 172 Horse-power calculations 122 Horse-power tables 372, 390 Hoskins giant 210 Hull construction 270 Hungarian riffles 147, 289 Hutchins, J. P 181, 266 Hydraulic elevators 214 mean depth 86 mining 50 radius 86 Hydraulicking, cost of 227 water for 228 Ilmenite i Iron ore mining 56 Keystone drill for prospecting 44 for blasting 276 Klamath River placers 16 Klondike placers 16 laws 348 mining . . ' 244 prospecting 349 Knight bucket 260 Knuckle-joint 210 Kutter, on ditches 98 INDEX 419 PAGE Land patents 338 Law of apex 335 California mine 344 Klondike 348 Laying pipe . I75 Le Conte on water transportation 83 Lead joints !y8 Leslie's formula, ditches 0,5 Lewis and Clark exposition 325 Leveling I9 i; Lidgerwood cableway , . . < 258 Lime cartridges 52 Lindgren Waldmer 14 Little Creek, Alaska 137 Locating claims 339 Log washers 250 Long Tom 71 Lonridge, C. C 198 Loss of head in pipes 128 Lovett concentrator 331 Machinery for dredges 295 Magalia, Cal 248 Magnetic separation of black sands 321, 332 Magnetite i Marion Company's dredges 300 Masonry dams 156 Mattison, E. E 174 Measurements of gold (table) 365, 369 giants 225 streams 162 water 161 water by color 172 weirs (table) 160, 403 Mercury in sluices 238 Mill sites 347 Mine laws 333,345 Mine maps 222 Miner's head day 225 420 INDEX PAGE Miner's inch 159 duty of 97,225 (tables) 372 Mining by booming 57 coal piles 59 by drifting 247 by fire Si, 245 in Alaska 244 in Georgia 246 in North Carolina 249 salt 53 by steam points 245 Mother lode 5 Neville, Sir John, on ditch erosion 207 North Carolina 4, 249 Nozzles 213 Nozzles (table) 390 Nozzle spouting velocity 211 Nozzle, duty of 224 Nuggets 15 Panning 62 Pan testing of placers 25, 28 Packard, G. W 312 Pay dirt 4 Perimeter 199 Phillips, J. W 205 Pipe, areas (table) 395, 402 bends (table) 183, 381, 385 contraction and expansion 176 corrosion 17, 132 discharge 395 Pipe formula, Chezy's 96,116 Coxe-Weisbach 181 Rankin's 182 Smith's 172, 181, 206 Pipe friction 131, 180 joints 176 INDEX 421 PAGE Pipe laying I7S lines and ditches 135^ 175 loss of head in 128,180,409 painting 175, 183 safe head for riveted 404 safe working pressure 394 strength of . . 182 thickness 395 tables 395 weight of 395 Placer calculations 22, 24 claims 20,343 cross-sections 23 definition of i, n dry 7,i7 geology of i investments 22, 137 prospecting 7,19,227 sampling 24 testing with bore-holes 23 drifts . . . '. 42 pans 25 Platinum in black sands 267 in Caribou sands 267 Poncolot formulas, ditches and pipes 206 Power plant for dredges 293 Pressure box 176, 188 Previous staked claims 20 Prospecting with drills 22, 44 Pump for tailing 293 Quarrying 51 Quicksilver in sluices 233 Radford's Factor 35 Railroad lands 337 Rankin on pipe 182 Raymond, R. W 33$ Recording locations 34* 422 INDEX PAGE Record of test holes . . . . . . . . . 35 Reservoirs 153 Retorting mercury 235 Revolving screens 285 Riffles, block 141 cast iron 143 charging 230 Hungarian ....... 147 iron rail 142 pole .. . . 138 slot 134 stone 142 Risdon buckets 276 River claims : 354 dredging laws, Canada 362 U. S. 336 Rivers, ancient 14 recent 14 Riveted steel pipe 131 Rockers 66 Rubbing surface 85 Safe velocity in ditches 108, 194, 201, 207 Salt mining 54 Sampling placers 25 San Juan River, Cal ... . 2 Screens, rotating 285 shaking 287 Sea beaches 3 Selecting a dredge 265 Self-contained dredges 30 Sellards, E. H 247 Settling dams 155 Seward Peninsula 4, 137 Shaft mines 239 Shaft testing 33 Shaking screens 287 Sierra Nevada Mt., deposits 14 Siphons 205 INDEX 423 PAGE Slot riffles 139 Sluice-box area ' 75, 85 calculations 84, 88 construction . 70, 78 depth 87 dump 96 grade 77,89 length 76,80 size of 84 Sluice, stone pavements 142 charging the 230 mercury in the 230 tunnels 205 Smith, Hamilton, on pipes 172, 181, 206 Snake River, Idaho 72 Spatterwork 54 Spouting velocity 211 Spuds 295 Square root 402 Stacker 292 Stadia chart 224 Standpipe valve 185 Stanniferous deposits n Steam measurements 162 Steam point 245 shovel mining 256 thawing 245 Stewart, C. B 135 Storage reservoirs 153 Storey, W. B 206 Stovepipe joint ... r 119 Strength of pipe . . . ; . . -r . r% 182 Suction dredges 282 Surface rights 21 Survey of ditch line i53> 190 Survey of progress 222 Table of areas ; 402 angular resistance 382 424 INDEX PAGE Table of circular bend 385 discharge through nozzles 390, 407 discharge through orifices 40 flow through channels 387 flow through pipes 376 giants 390, 402 gold values 369 horse-power from nozzles 390 horse-power per miner's inch 372 horse-power per cubic foot 373 loss by friction 409 riveted pipe 394 safe head for 404 weight of pipe 394 weir measurements 408 Tailing pump 293 Tailing stacker 292 Telephone lines 207 Testing placers 22 with drifts 42 with drills 31 with shaft 31 Test records 35 Tinker, E. B 224 Tin deposits n Traction dredges 297 Transporting power of water 80 Traveling tower 258 Trestle flumes 163 Trinity Co., Cal., placers 9 Trough washers 69 Tumblers 295 Tundra 3 Tungsten 3 Tunnel mining 238 Tunnels in ditch lines . . 143 Tunnel sluicing 153 Undercurrents , , , , r 145 INDEX 425 PAGE Value of gravel deposits 24, 29 Valuing dredging ground 36 Valves, air 187 water 185 Velocity of flow 87 table 407 Virginia gold deposits 5 Washing gold with centrifugal pumps 291 Washing gold with logs 250 screens 285 Water area . 371 cartridge 52 depth in ditches 108 duty of 97, 266 for hydraulicking 228,412 friction 180 gates 185, 189 hammer 187 loss 112 measurements 162 by color . 171 by giants 224 pressure 394 rights 21,367 supply 153 transporting power of 80 to dirt removed 97 velocity in ditches 108, 194, 201, 207 weight of 371 Waterfall mining 58,226 Weatherbee, D'Arcy 294 Weir measurements 408 Weisbach on pipes 181 Well drill test holes 33 Wet perimeter 85 Wooden stave pipe 123 Wood's dry placer machine 311 Wright, P., on gold movement in ditches 280 Yukon, Canada 348