rii :^-l^ CAIIFORlttA. DEFT. OF NATURAL RESOURCES. DIVISION OF lENES. BULLETIN. no. 36 i m m w ^jkT voL^ 4 u hix ^. THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DAVIS l_i^ ri f^fT II I II mill nil II mill nil III! III! II III! Hill mil III nil III I II f i ]- BULLETIN No. 36 SAN FRANCISCO. MAY. 1905 GOLD DREDGING IN CALIFORNIA ISSUED BY THE CALIFORNIA STATE MINING BUREAU FERRY BUILDING, SAN FRANCISCO LEWIS E. AUBURY State Mineralogist W. W. SHANNON SACRAMENTO - SUF 1905 NiVERSlTYOFCAUFdikN! DAV!S FEB 2 1953 SUPERINTENDENT STATE PRINTING LIBRARY ' LIBRARY UNIVERSITY OF CALIFORNIA DAVIS II I II mill mill mill mi im im n im nm nm m im m i Hft \ a I < ^ 5 //. aV / y jti. II I II mill ml II ililM nil mi im n im nm itm m im m i n EOMAJaMmi q^X/iq g'-jM > «^ YJ AIM / UA3flUa \ yCitfC \ .T:-;'- '. '^"'.n I 1 . ]| ' "-~- t ,i 1 i 1 1 ' ' .VAV ■ ■ 6^A■^.-s.■^-^ i^ 1 1 ' ^ ' ■ 1! ■'f H ' 1 1 1 Ji ni BULLETIN No. 36 SAN FRANCISCO, MAY, 1905 GOLD DREDGING IN CALIFORNIA ISSUED BY THE CALIFORNIA STATE MINING BUREAU FERRY BUILDING, SAN FRANCISCO LEWIS E. AUBURY State Mineralogist SACRAMENTO W. W. SHANNON ... - SUPERINTENDENT STATE PRINTING 1905 ML*—^- AM ^iRaamwDHa ~ THS^ALQA lilOlUAO \ )K.3 eiwaj — -3TAT8 mi %:'K ^■^^ BULLETIN No, 36 SAN FRANCISCa MAY, 1905 GOLD DREDGING IN CALIFORNIA ISSUED BY THE CALIFORNIA STATE MINING BUREAU FERRY BUILDING, SAN FRANCISCO LEWIS E, AUBURY State Mineralogist SACRAMENTO W. W. SHANNON . . . . SUPERINTENDENT STATE PRINTING 1 905 LETTER OF TRANSMITTAL. To HoK. George C. Pardee, Governor of California, and the Honorable Board of Trustees of the State Mining Bureau: Gentlemen : I have the honor to transmit Bulletin No. 36, ' ' Gold Dredging in California." The issuance of this Bulletin has been con- templated for some time, and some information concerning the subject was Qbtained in 1902, but owing to the rapid changes which have affected this branch of the gold mining industry, and the difficulty met with in securing accurate data which would serve to illustrate the actual conditions of gold dredging in this State, it has been deemed best to delay the publication of the report until the present time. The items of costs of operation, which are so vital to a publication of this nature, have l^een extremely difficult to obtain from many of the companies engaged in dredging. This has not been due particularly to any intention on the part of the companies to withhold the information, but to the fact that many operators have not until recently preserved a detailed record of expenditures; I wish to here extend many thanks to Col. J. E. Doolittle for his valuable assistance in the preparation of this Bulletin, and also to the many operators who have furnished information and assistance which have made this publication possible. I also wish to thank Mr. 0. W. Jasper of Oroville, Mr. Howard D. Smith, and Mr. A. H. Ward, who rendered assistance; also many others whose names are not here mentioned and who have aided in the work by furnishing valual^le information. Engaged at various times in securing data for this report, and who were employed as Field Assistants, were Mr. P. C. Dubois, Mr. John D. McGillivray, Mr. William Forstner, and Mr. G. Holmes, to whom I wish to express due recognition for their ser\nces. Very truly, LEWIS E. AUBURY, State Mineralogist. San Francisco, May 15, 1905. CONTENTS. HISTORY ------- - - . 7 AREA OF DREDGE GRAVEL - - ... 14 GEOLOGY ---------------- 16 AGRICULTURE - - - ------- 17 YIELD FOR 1903 - - - - - 19 THE DREDGE - - - - - - - - - - - - - - - 19 SCREENS, SLUICES, ETC. - - - - 35 CREW OF A DREDGE ------------- 41 WORKING COSTS -------------- 42 PROSPECTING AND EXAMINATION OF CONDITIONS '----- 60 OROVILLE DISTRICT ------ - - 68 YUBA DISTRICT --------- 88 BEAR RIVER DISTRICT ------------ 9I FOLSOM DISTRICT -------------- 92 CALAVERAS COUNTY - - - - - ^ - - - - - - 98 PLUMAS COUNTY -------------- 98 SHASTA COUNTY - - ------------ 98 TRINITY COUNTY - - - - - . . - - 102 SISKIYOU COUNTY ------------- 105 APPENDIX-CALIFORNIA STATE MINING BUREAU - - - - -111 DREDGE DATA --------..--- /-oW^r LIST OF ILLUSTRATIONS. Page. No. 1. Relief map of California Frontispiece 2. Map of Oroville dredging lands Folder 3. An "old timer" 8 4. The old method of working the ground below Oroville }> 5. Treat's old workings on Feather River 11 6. First successful dredge in California. 12 7. Marion steam shovel dredge, Oroville 13 8. Tailings piles after dredging . 18 9. Dredger hull, in course of construction 20 10. Dredger in course of construction, showing steel gauntry 21 11. Digger end of ladder — latest type of close-connected buckets. Bucyrus type 22 12. Digger end of ladder — latest type of intermittent buckets. Risdon type..- 23 13. Digger starting cut on top of ground. L 24 14. Bucket line in operation - 24 15. Close-connected buckets (loaded), Bucyrus type 27 16. Close-connected buckets, 5 cubic feet capacity 28 17. Open-connected buckets, 5 cubic feet capacity, Risdontype 2ft 18. Boston and Oroville Company's dredge, showingspuds 31 19. Tailings stacker, belt conveyor., 32 20. Tailings stacker, bucket conveyor 33 21. Latest bucket stacking ladder 34 22. Showing sand pump working ^34 23.- Showing revolving screen 36 24. Gold-saving tables — Hungarian riffles and quicksilver 37 25. Gold-saving tables — cocoa matting and expanded metal riffles 39 26. Bucyrus type of dredge, with close-connected buckets, shaking screens, belt conveyor, and spuds 43 27. Risdon type of dredge, with open-connected buckets, revolving screen. bucket conveyor, and headlines , 45 28. Oroville Gold Dredging and Exploration Company's dredge, " Biggs Xo. 2 " .=)3 29. Keystone drill at work at Oroville to prospect for values and determine character of gravel -- 62 30. Typical vertical sections of borings in four different California fields m 31. General view of the Oroville dredging district 68 32. General view of the Oroville dredging ground on Feather River, looking north 69 ;33. Dredge of the Feather River Exploration Company, Oroville. Risdon type 71 34. Front end of Dipper dredge, Oroville 72 35. Stacker end of dredge, showing height of tailings piles. Lava Beds Dredging Co., Oroville 72 36. Oroville Gold Dredging Company's dredge. Marion steam shovel type. - 74 6 LIST OF ILLUSTRATIONS. Page. No. 37. Indiana Gold Dredging and Mining Conipany'.s dredges, No. 1 anil No. 2, Bucyrus type 75 38. Indiana Gold Dredging and Mining Company's dredge, Bucyrus type, showing close-connected buckets 76 39. Kia Ora dredge, Oroville. Risdon type 77 40. Cherokee dredge, Oroville. Bucyrus type - 7i) 41. Pennsylvania Gold Dredging Company 80 42. Pennsylvania Gold Dredging Company's dredge, Oroville. Golden State and Miners' Iron Works, builders . 81 43. El Oro Dredging Company's dredge, Oroville. Link Dredge Machine Com- pany's type 82 44. Viloro dredge, Oroville. Latest type Bucyrus dredge . . _ 83 45. Boston and Oroville Dredging Company's dredge, Oroville. Risdon type__ 84 46. Boston and Oroville Dredging Company's dredge, "Continental." Bucyrus type as remodeled 85 47. California No. 3, Oroville, built by the Marion Steam Shovel Company 86 48. Marigold No. 1, Marigold Dredging Company, near Oroville 87 49. Front view of the Marigold Dredging Company's dredge, near Oroville. -_ 87 50. Stacker end of Marigold Dredging Company's dredge 89 51. Yuba Consolidated Gold Fields dredges, each of 6 cubic feet bucket capacity. Bucyrus type 89 52. Yuba Consolidated Gold Fields dredges, each of 6 cubic feet bucket capacity. B ucyrus type 90 53. Ashburton Mining Company's dredge, at Folsom, Sacramento County. Buckets 7^ cubic feet capacity 94 54. El Dorado No. 1, Folsom field. Latest type of Risdon boat 95 55. Dredge of the Colorado-Pacific Gold Dredging Company, Folsom 96 66. Syndicate Mining Company's dredge, Folsom. Bucyrus type 97 57. The bedrock of the Sacramento River at the mouth of Middle Creek, above Redding 99 58. Current breakers and caissons of the Huron Submarine Mining and Con- struction Company, at Redding --- 101 59. Huron Submarine Mining and Construction Company's caisson dredge, above Redding -. ' 101 60. Galvin Gold Dredging Company of Weaverville, Trinity County 102 61. Galvin Gold Dredging Company's dredge. Trinity County, showing char- acter of gravel ..- 103 62. Poker Bar dredge, Trinity County 104 63. Dredge of the Yreka Creek Gold Dredging and Mining Company, Siskiyou County ----■'- 106 64. Consolidated Mining and Dredging Company's dredge and caisson 107 65. Ferry Building, San Francisco HO 66. Mineral Museum, State Mining Bureau --. 113 67. Library and Free Reading-Room, State Mining Bureau 115 68. Laboratory, State Mining Bureau 117 69. Map of field of operations in Folsom District, showing locations of dredg- ing companies Folder 70. "Dredge Data" Folder GOLD DREDGING IN CALIFORNIA. :. DOOLiTTLE, e.m:. HISTORY. It is popularly supposed that mining for gold with dredges is an industry which has grown up within the last decade, and that it was a success almost from the beginning. This is not true. There are bleaching skeletons of dredges scattered over California and New Zealand, some of which were built nearly half a century ago. There was a dredge near Oroville, on the Feather River, in the fifties. It is over forty years since dredging was first tried in New Zealand. Spasmodic attempts were made in this direction on the Pacific Coast and in New Zealand from that time on. These efforts, futile as they were, so far as giving dividends to shareholders go, were of great value to the miner and mining engineer of to-day. These failures were their warnings. As a result, this class of mining, if properly directed, is now as safe as any, provided that skilled investigators direct the investment and use of capital, and see that it is only invested where conditions permit of successful work. Any one investigating the processes at Oroville or Folsom, or in New Zealand, where conditions are known by actual practice, will find that the difficulties have been largely overcome because the conditions have been studied by skilled men at large expense, and met with appli- ances fitted for the local needs, not only as to the digging of the ground, but also as to the saving of the gold. But under other conditions, in other districts, the dredges so suc- cessful at Oroville or Fol'^om, or in New Zealand, would be failures as to some of their parts. To explain: At Oroville, the gravel is loose, free from clay. There are no large bowlders, the bedrock is soft, the gold is fine and it easily amalgamates. Along the streams in the mountains of California the bowlders are larger, the bedrock harder, and in places in Idaho and Colorado the gold will not amalgamate owing to the presence of arsenic. Then there are many other condi- tions that differ in other places. Some of these difficulties may be overcome by slight changes, either in the digging part of the dredge 8 GOLD DREDGING IN CALIFORNIA. or in the gold-saving appliances; but some of them, such as hard bed- rock, in cases are fatal to successful dredging. The conditions bearing on the cost of operation are such that each tract of ground becomes a problem in itself, and any attempt to use the costs obtained under one set of conditions, on which to predicate those which would hold under another, without a thorough knowledge of the various elements which enter into the problem, will lead to large discrepancies between the results predicted and those actually obtained, with a possible consequent failure of the enterprise. . There have been built in California many dredges that have failed AN -OLD TIMER,' ILLUSTRATIN(; ONE OF TH DREDGE BUILDINC;. EARLY MISTAKES OF and become total losses. Yet to-day, with all the data at hand for any careful investigator, there should be little excuse for failure. The varying conditions that exist where dredging is being done at Oroville, Folsom, in Trinity County, in Idaho, Montana, Colorado, British Columbia, the Klondike, Alaska, and New Zealand, both as to the digging of the gravel and the saving of the gold, give the miner the actual experience necessary for him to come to conclusions under most circumstances. The illustration entitled "An Old Timer" illustrates one of the early mistakes in dredge building in this State. This machine, on which 10 GOLD DREDGING IN CALIFORNIA. some $40,000 was expended, is very odd, in view of later improved gold dredges. The bucket ladder is made of two pieces of 4-inch by 18-iuch Oregon pine. The buckets are made of No. 14 iron; the links of %-inch by 2-inch tire-iron, and put together with i/o-inch carriage bolts. It was driven first by steam and then by a gasoline engine. It is reported to have dug 8,000 yards in the period between March, 1902, and July, 1904. Its running time could hardly have been over one hour per day, being shut down almost constantly for repairs. It now stands idle in ground that dredged 30 cents per cubic yard. The single-bucket or spoon dredge was evolved in New Zealand in the early sixties, and was worked entirely by hand. A steam single- bucket dredge was built in 1870. About 1880, bucket and ladder dredges were introduced. These were nearly all worked with power furnished by current wheels. The first steam chain bucket dredges of the present type were introduced about 1882. One dredge of this class, built about that time, was successfully worked for sixteen years. On account of the success of a dredge in 1889, on a branch of the Molyneux River, some twenty were built at an average cost of $17,500, but were failures, owing mainly to the fact that the ground was not suitable for dredging and the management bad. Many of these dredges were floated down to the Molyneux River, and under new ownership were made successful. Then a number of suction dredges were built, but proved complete failures. Since then, the endless-chain bucket dredge, similar to those used in California, has held the field. In New Zealand, at the end of 1902, there were 201 dredges working, 52 stand- ing, 23 building, 14 under removal, and 2 wrecked— a total of 292. The first successful endless-chain bucket dredge in the United States w^as built in 1894 at Grasshopper Creek, in Montana. Many attempts to dredge had been made on the Pacific Coast, but it was not until 1897 that a dredge of the present ty^DC was built in California. In the sum- mer of 1895, W. P. Hammon and Warren Treat, who were interested in horticulture near Oroville, wel'e working some gravels for gold on property now owned by tlie Feather River Exploration Company. Mr. Treat had made a pit about 100 feet square down to bedrock, using a centrifugal pump to keep the water out, and hauling the gravel in wagons out to small sluice-boxes, where it was w^ashed. The gravel was handled several times by manual labor, and in spite of the heavy costs for labor and pumping water, there was a profit. Mr. Hammon had another pit, but on approacliing bedrock found that the great amount of water coming in would make mining at a profit difficult. My attention was called to these cases and I visited the property, and, after consulting with Mr. Hammon as to the best process for working, suggested hydraulic elevators; but it Avas found, on investi- 12 GOI-D DREDGING IN CALIFORNIA. gation, that the distance necessary to convey water and the large amount of water in the ground itself, to be handled, would make this impracticable. At that time little was known of dredging in Califor- nia. However, I had purchased some of the land through Mr. Hara- mon and A. F. Jones. A few months later I met, in San Francisco, Capt. Thomas Couch and F, T. Southerland, from Montana, who were looking for mining properties. To them I suggested the Feather River gravels, and there they went, and, with Mr. Hammon, after prospect- ing for about a year, purchased 1,000 acres, which is now being worked by five dredges. ^W^tmdl^^ m^ h. / ^ ., ILL. No. (■). DREDGE No. 1, FEATHER RIVER EXPLORATION COMPANY, OROVILLE. RISDON TYPE. FIRST SUCCESSFUL DREDGE IN CALIFORNIA; STILL OPERATING. While they were prospecting this ground, R. H. Postlethwaite, a New Zealand engineer, who had come to California to look over the dredging field, had constructed, by the Risdon Iron Works, a 314 cu. ft. bucket dredge, to be used near Smartsville, on the Yuba River. While the dredge itself was satisfactory, the conditions did not permit of a financial success in working. The first dredge at Oroville, built for the Feather River Exploration Company, began work March 1, 1898. It was designed by Mr, Postlethwaite, and built by the Risdon Iron Works. This dredge is still being successfully operated; it has been strengthened, however, in parts. 14 GOLD DREDGING IN CALIFORNIA. Steam was used at first, but now all the dredges in the Sacramento Valley districts are worked by electric power. During the first two years of successful dredging at Oroville with endless-chain bucket dredges, a number of attempts were made to dredge with suction and other styles of dredges, but all these, with the exception of one s.team shovel dredge, were failures. AREA OF DREDGE GRAVEL. The following table will show, in a general way, the acreage of gravel under consideration for dredging. It is probable that these figures will in many cases be increased and other districts opened: Average VaUie per Cubic Yard, District. Acreage. in cents. Oroville 7,5(X) 17 Yuba River t 5,000 25 to 30 Bear River 1,000 18 to 30 Folsom 5,000 15 to 25 Calaveras 350 16 to 22 Stanislaus 1,200 15 to 30 Trinity 1,000 Shasta 1,500 Siskiyou 1,000 Plumas 1,500 Total 25,050 In Stanislaus County considerable prospecting has been done, and about 1,200 acres has been proved to contain values sufficient to war- rant dredging. In Shasta County, drilling is being done on Cottonwood Creek and on land opposite Redding on the Sacramento River, and on Clear Creek. In El Dorado County some land on the South Fork of the American River, near Coloma, is being considered, but not yet reported proved. In all these districts, and at other points in the Sacramento water- shed especially, there are considerable areas of dredge gravel, most of which have been more or less examined, but not proved to be of suffi- cient value to work at the present cost. The best dredge authorities claim that by proving good grade of pay in some of this outlying ground and reducing working costs, at least 25,000 acres will in time be added to the fields which it is already decided to dredge in the Sacramento Valley. In this connection experiments are being made with a view to work- ing by a process similar to the present dredging system, but at much lower cos,t. Those interested do not care to give out any data at present. GOLD DREDGING IX CALIFORNIA. 15 It may seem a simple thing, to those who know, to say that there is a great diversity in methods of gravel mining caused by varying con- ditions of the deposits, and that the method in vogue in one case may mean failure in another. Yet the want of this knowledge has been the cause of immense waste of capital. There have been large simi^ of money lost in trying to hydraulic drifting ground. Attempts have been made to use hydraulic elevators to work- dredging ground, where there was an excess of water to be handled. Dredges have been built to work ground that could be worked only by means of hydraulic elevators. There are many thousands of acres of gravel, mostly lacustrine deposits, in California and other states and territories on the Pacific Coast and in Alaska that is free from water and should be worked with steam shovels, which people are now exploiting with a view to working with dredges. In other words, they are proposing to make a condition— by flooding the ground with water— that means an unnecessary cost. A study of the conditions existing wiU lead to con- elusions as to methods to be adopted; and in this way only can economic success be made. The different kinds of gravel raining, it may be said, are : First — Ordinary hydraulic mining, requiring water under pressure and a good dump, with gravel easily removable. Second — There are the drift mines in layers of gravel deposits over- capped with lava or other material of such great depth that only underground or drift mining is possible. T/i /re?— There are the bars along the rivers, based on hard bedrock, that must be worked with hydraulic elevators for want of dumping facilities, and which can not be worked with dredges because the bed- rock is hard. Yet, in these cases it must be understood that even hydraulic elevators are of no use if there is an excess of water. Fourth — There is the gravel with an excess of water, with soft bed- rock, that can only be worked with dredges. It would be futile to hydraulic the lava-capped di^ddes in Placer and other counties in California ; yet this has been attempted. They must be drifted. It would be impossible to make an economic success of the use of hydraulic elevators at Oroville or Folsom, on account of the excess of water in the gravel ; yet this has been attempted. In some mountainous districts in California, dredges have been tried and have proved failures, because the bedrock was too hard to dig and the gold could not be lifted. Then there are cases where the excess of water prevents the use of hydraulic elevators, and the hardness of the bedrock and the conse- quent conditions that usually follow prevent the use of dredges. Yet 16 GOLD DREDGING IN CALIFORNIA. inventions not now known may be made to work these gravels at a profit. Then again, there are large tracts of gravel, usually of lacustrine deposit, in the Sierras, not deep, and not overcapped with lava, that afford good opportunity for the use of steam shovels. GEOLOGY. While dredge mining is being conducted, under conditions appar- eiitlv satisfactory to those engaged in the industry, in the Sacramento Valley districts of Oroville, Yuba, Folsom, and Calaveras, and on the Bear River, there is an interesting geological feature worthy of more than a passing thought, and that is that all of this dredging is being done on what may be considered a superficial layer of gravel, under- laid by a stratum of volcanic mud and pand, the deposition of which, of course, antedated the deposition of this gravel. The gold-bearing veins existed and were eroded for a great period of time, antedating the volcanic activity which is such a prominent feature of the Sierra Nevadas, and the ancient rivers deposited their gold-bearing debris upon the original bedrock, both within the limits of their rims and upon the floor of the great interior valley — the present valley of the Sacramento River— which at that time was a vast fresh-water lake. Subsequently the volcanic activity resulted, in many instances, in filling the old gold-bearing rivers to the brim with a vast quantity of volcanic material, now recognized in the mud, tufa, and breccia over- lying the ancient river channels, and, as a matter of course, this volcanic material was carried out into the estuaries, extending even into the lake itself to a considerable distance, and covering the pre- viously deposited gold-bearing gravel. The subsequent uplift of the whole Sierra Nevada system has resulted in the exposure of these lake- beds along the eastern edge of the Sacramento Valley. The subsequent erosion of modern streams, cutting through the original ancient river channels, and often into the underlying bedrock, with its complex system of gold-bearing veins, resulted in the formation of a later bed of gravel, which rests upon the volcanic sands and mud of the lake. Doubtless this process has been repeated a number of times, and this point could be determined by drilling or by sinking shafts. But it is clearly evident that the present dredging is not in deposits of gravel resting on the true bedrock— the slates and schists which form the adjacent foothills— but in later, and, quite likely, less valuable gravel. In many ancient river channels there are sometimes two or three gold-bearing strata, called by the miners "leads," and the stratum GOLD DREDGING IN CALIFORNIA. 17 of gravel on the bedrock is usually the richest, while the upper strata are relatively of less value in gold per cubic yard. There are, how- ever, instances contrary to this, where one of the upper strata is of more value; but this Is due to local conditions, probably generally to the erosion of other preexisting beds of gravel. Why this principle should not be proved true in this lake is well worth considering. Similar conditions have been found to exist in the Cariboo country in British Columbia, and in some of the mountain districts of Cali- fornia outside of the Sacramento Valley region. The discovery, however, of good value in these lower strata might not lead to satisfactory economic results, because the expense of hand- ling large bodies of water that might be encountered would handicap any venture in that direction. AGRICULTURE. The question of reclaiming these lands for agriculture after they shall haA'e been dredged is hardly worth discussing at present ; but, in course of time, as farming lands become more valuable, they could be leveled with scrapers run by electric power and then covered with soil hydraulicked in the foothills and run down by flume. In the meantime, however, a large proportion of the rocks will disintegrate and so make soil. However, should these lands be reclaimed, their average value for agriculture would be much higher than it was before they were sold to the dredge companies. Some of them were unfit for cultivation and very little were worth more than from $15 to $35 per acre in the Oroville district, but probably as much as from $50 to $60 per acre in the Folsom district. A small proportion was covered with orchards and vine- yards, and so was worth more. Yet, as much as $1,000 per acre was paid by the miners for some land about Oroville, and an average of about $100 per acre for the whole Oroville tract. In other words, the owners received from the miners from three to five times the value of their property for agriculture in this district. Granting that these lands will never be reclaimed, it may be asked, is not their destruction a distinct benefit to the State? Take the Oro- ville district, for instance. The farm owners have received nearly a million dollars for their land. There have been built over thirty dredges and several shops, at a cost of nearly $2,000,000, a large part of which has been paid in wages. Probably as many more dredges will be built before the tract is worked out. It is estimated that the cost of repairs and renewal of parts during the life of each dredge will amount to as much as the first cost. It would take twenty years with thirty dredges to work the tract, and this means the employment of at least 500 men, with families dependent upon them, to say nothing of the 18 GOLD DREDGING IN CALIFORNIA. men employed in the buiiding of the dredges and in the shops. This means the payment, in wages, of over $1,000,000 a year, and a livelihood for two or three thousand people, if we include those dependent upon the wage-earners. From this tract will be produced in gold, to be added to the wealth of the State, about $60,000,000. From the dredging ground in the Sacramento Valley districts (estimated at 25,000 acres) which have been proved, and which it has been decided to work, there should be produced an average of 15 cents per cubic yard; and if we allow a depth of 9 yards, the estimated 8. TAILINGS PILES AFTER DREDGING. OROVILLE. MARIGOLD DREDGING COMPANY, 25,000 acres will produce $163,350,000 in gold, to be added to the wealth of the State. Placing the average value of all this ground, both that which is and that which is not suitable for agriculture, at $40 per acre for that pur- pose, the loss amounts to no more than $1,000,000. In connection with the question of reclaiming these dredging grounds, it may be mentioned that James H. Leggett, owner of dredges at Oroville, has begun some experiments by planting eucalyptus and olive trees on the rock piles, with a few spadefuls of earth at the roots of each tree, and they are thriving. In New Zealand, experiments with a view to making forest land of the dredge ground are reported to be meeting with success. GOLD DREDGING IN CALIFORNIA. 19 YIELD FOR 1903. The output in gold, in 1903, from all the dredges in California, according to the returns made to the United States Mint, was $1,475,749. The yield for 1902 was $867,665, showing an increase of $608,084 for 1903. The returns for 1903 were from 25 dredges in the Oroville district in Butte County, 3 dredges in the Folsom district in Sacramento County^ 1 dredge in Siskiyou County, 1 dredge in Trinity County, and 1 dredge in Yuba County. Of the total for 1903, $1,329,998 came from Butte County, meaning the Oroville district. There will be an increase for 1904 beyond the proportionate increase in the number of dredges, because the new dredges are of larger capacity and improvements have been made in the old dredges. At the beginning of 1905 there were, in the Oroville district, 28 dredges; in Calaveras County, 1 dredge; in the Folsom district, 5 dredges ; in Shasta County, 2 dredges ; in Trinity County, 1 dredge ; in Siskiyou County, 1 dredge; in Yuba County, 2 dredges; total, 40 dredges, as against 31 dredges for 1903. Some of the dredges worked only part of 1903, having been built during the year. Taking into consideration the increased average yardage of these dredges and the fact that a number of new ones will be in operation during part of the year, the yield for 1905 may be expected to be considerably more than double that of 1903. THE DREDGE. The continuous-chain bucket dredge is practically the only type that is in successful operation in the gravels of the Sacramento Valley dis- tricts. New Zealand, Montana, Idaho, Colorado, and Oregon, and it holds the field in gravel where there is an excess of water and where conditions are generally favorable for dredging. There are many dif- ferences in detail in the different dredges, but under favorable con- ditions, such as exist in the Sacramento Valley district, in New Zealand, in the States named, and in Alaska, the results obtained from these dredge-s do not differ much except where the conditions are abnormal and difficult. The dredge in use is much like the ordinary continuous- chain bucket dredge used for other work, so far as the digging part goes, except that the size of shaftings and strength and weight of all parts are greatly increased. For gold mining it consists of a hull, a digger, screen, sluice-table and sluice-boxes, a stacker, a pump, amalga- mator, and sometimes a sand pumpj with lines or lines and spuds to hold the boat in position, and separate motors for each part where power is required. 20 GOLD DREDGING IN CALIFORNIA. Hull. — So far, in California, all the hulls are made of wood, but some dredges sent to Dutch Guiana have been built with steel hulls. This hull is rectangular in shape, with a slightly reduced width in the bow of the boat. As, practically speaking, all the parts of the machinery of a dredge are renewed during the life of the dredge, it has been suggested that steel hulls would give a longer life and more solidity ; but so far none have been constructed, and probably will not be until there is a nearer approach to perfection of the machinery and a better knowledge is had of the limits of the capacity of the dredges, ILL. N.i. :>. HULL OF BOSTON AND ORoVILLL DREDfilNd COMPANY'S DRED(iE, ORO- VILLE, IN COURSE OF CONSTRUCTION IN 1901. for the tendency is to discard the smaller dredges and to build those of larger capacity. To allow the digging ladder and its chain of buckets to descend to the bottom of the ground to be worked, the hull in the forward part is divided by an opening called the well, in Avhich the ladder is moved up and down. The dimensions of the hull vary with the size of the buckets, as may be seen by reference to the accompanying folder of particulars as to dredges. The hulls vary in width from 30 to 40 feet, in length from 80 to 120 feet, and in depth from 7 to 9 feet. Gauntries.— y.ear the center of the hull there is a main gaimtry, to support the upper end of the digging ladder and the main drive of the 22 GOLD DREDGING IN CALIFORNIA. bucket chain. These have commonly been made of wood, but lately some have been constructed of steel plates. There is a stern gauntry to support the tail sluices, the conveyor ladder, and the spuds, if they are used. Digger. — This consists of a ladder frame, built strongly of iron or steel, so that a chain of buckets may travel continuously around its length. On the best of these, manganese steel is used in the lips and bushings of the bucket, and on the ladder rollers. It has been found that a large saving in cost of repairs, which is the main cost, and ILL. No. n. DETAILS OF BUCKET CHAIN, LATEST TYPE BUCYRUS DREDGE— BIGGS No. 2. where future saving can be made in the cost of dredging, is in strengthening the wearing parts of these buckets and links. A refer- ence to the tables of cost will show how large is the proportion of the cost of working caused by the breaking of buckets and other parts of the digger. However, this has been very much reduced since the first successful work was done at Oroville, and is being continually reduced as new dredges are constructed. The greatest improvements are now being made by the use of special steels and in the shape of the buckets. The bucket line is either what is called of a "close connection" or of an "open connection"; that is, the buckets follow each other on each link of the chain, or there are open linlcs between the buckets. Wher- GOLD DREDGING IN CALIFORNIA. 23 ever there are no large bowlders and the gravel is comparatively loose, there can be no question that the close-connected buckets, with less speed, will dig more ground than will the open-connected. As to the difference between the open- and the close-connected bucket in hard ground, the question as to the greatest capacity has not been settled, but it is probable that the close-connected bucket will give more sat- isfactory results. However, where there are large bowlders, the open connection must be used, or the backs of the buckets will be jammed and broken. The close-connected buckets are run at a lower rate of chain speed than the open-connected buckets, the former moving at the ILL. No. 12. DIGGING END OF " EL DORADO No. 1," IMPROVED RISDON TYPE, INTER- MITTENT BUCKET. rate of about 50 feet, or 18 to 25 buckets, per minute, and the latter at the rate of 60 feet, or 12 to 15 buckets, per minute. Yet, in hard ground the open-connected buckets are filled to their full capacity more often than are the close-connected buckets. In this connection it may be said that most of the newer dredges at Oroville and Folsom are equipped with close-connected buckets. Owing to the greater weight of the close-connected chain of buckets and greater yardage handled, more power is required than for open- connected buckets. The following tables will give an idea of this difference : ILL. No. 13. BUCYRUS MACHINE STARTING CUT IN TOP (xROUNI). VILORO DREDGE, OROVILLE FIELD. ILL. No. 14. BUCKET LINE IN OPERATION. LAVA BEDS DREDGE No. GOLD DREDGING IN CALIFORNIA. 25 The different motors in the Oroville Gold Dredging and Exploration Company's 5-foot Risdon dredge are of the following capacities: Horse-power. Main drive _- 50 Stacker and screens 20 Sidelines and head lines . 10 Ladder hoist 15 Water pump 40 Primer pump 3 Total 138 The average amount of horse-power used in the dredge was 90. No returns were made of the proportion of the full capacity of each motor used. The following figures are given by the builders of the Bucyrus, close-connected, belt-convej'or, shaking screen dredges, as to the horse- power of the motors as built : Dredge with 3 cu. ft. Buckets. Horse-power. Digging motor 50 Winch motor 15 Screen and conveyors 20 Water pump 30 Sand pump -- 30 Priming pump 3 Total 148 Actual consumption, about 100 H. P. Dredge with 5 cu. ft. Buckets. Digging motor 75 or 100 Winch motor 20 Screen 15 Conveyor 10 or 15 Water pump 50 Sand pump 30 Priming and clean-up 5 Total 235 Actual consumiition, about 125 to 150 H. P. Dredge with 6 cu. ft. Buckets. Digging motor 100 Winch motor 30 Screen 15 Stacker 15 Water _-- 50 Sand pump 50 Priming and clean-up 7^ Total 2671 Actual consumption, not known yet. 26 GOLD DREDGING IN CALIFORNIA. The following data have been given as to the actual consumption of power, as per report in L. J. Hohl's paper read before the California Miners' Association: For a 3 cu. ft. close-connected bucket dredge, with shaking screen and belt conveyor: Horse-power. Main drive 26 to 45 Stacker and screen 12 to 16 Water pump 45 to 50 Winches, maximum 28 Sand pump 32 to 50 For a 5 cu. ft. dredge of the same type: Main drive 42 to 70 Stacker and screen 10 to 20 Water pump 50 to 75 Winches, maximum 27 Sand pump, not tested. For a 5 cu. ft. open-connected bucket dredge, with revolving screen and bucket conveyor : Main drive 60 Water pump 52 Screen and stacker 18| Other motors, not tested. Yuba dredge, 6 cu. ft. buckets, close-connected, with shaking screen and belt conveyor. This dredge digs 60 feet deep : Main drive 108 Watei pump 68 Sand pump 63 Stacker 9 Shaking screen 11 Auxiliary supply 13 Buckets. — The buckets at Folsom, Oroville, and Yuba vary in size from 3 cubic feet capacity up to 8^ cubic feet, and it is proposed now to build a dredge at Folsom with buckets of 13 cubic feet capacity. They vary considerably in shape, and in the material used, but some of the best are those that are made with a cast nickel steel bottom piece, with sheet steel hood and manganese steel lips, and reinforced cutting edges. If a comparison could be made as to the breakage and consequent extra cost between the earlier buckets made and those now being turned out, a great advance would be shown, and greater advances are possible. This is a matter for the consideration of the manufacturers and the engineers in charge of the plants. As to the difference in cost of operating under favorable and simi- lar conditions with the different sized buckets, it may be said that the cost for labor is nearly the same for the small as for the large dredge, and much smaller per cubic yard for the larger; that there is a proportionately smaller cost for power and for repairs. Manage- ment and all other expenses are reduced in the larger dredges, pro- ILL. No. 17. OPEN-CONNECTED BUCKETS, RISDON TYPE, 5 CU. FT. CAPACITY. 30 GOLD DREDGING IN CALIFORNIA. vided, of course, that in their construction there is given, by the strengthening of the parts, as little loss by breakdowns. Then, it may be said, that the larger buckets will handle larger bowlders and so decrease the breakage in the bucket line. The parts being heavier, it is possible to dig harder ground. The increased yardage handled will mean a decrease in the interest cost on the original investment. As against this, it may be said that the first cost is much larger, and that better equipped repair shops are required. The weakest portions of the bucket bottom are the eyes and the parts coming in contact with the manganese or nickel steel wearing plates of the upper and lower tumblers. As these wear there is an increase in danger of breakage, and it is to the manufacturers that we must look for remedies in this respect, by the addition of more metal to add strength and compensate for wear, by improvement in the character of the steel used, and by changes in the faces of the tumblers in order to give better bearing and reduce the strain. Simpler and stronger parts of the best materials must be used to remedy the present evils. Spuds and Head Lines.— To keep the dredge in place, move it about, and hold it against the bank, there are two methods in use: (1) Two spuds, one of steel, and one of wood at the stern of the boat— the wooden spud being used when the steel spud is lifted and it is desired to "walk" the boat ahead. At the forward end of the boat are two steel-wire rope lines fastened to the shore to move the boat to right and left through an arc of a circle, and two at the stern. (2) Instead of spuds and lines, five lines are used — two at the stern, two forward, and one ahead to hold the boat against the bank. In the lighter and softer ground in New Zealand, the guy method seems to be preferred, but in Oroville both methods are in vogue. Where the surface of the ground is level, and the ground to be dug is soft and shallow, some of the dredge owners prefer the lines. An uneven surface of the ground, hard gravel or deep gravel makes the spuds preferable. Most of the largest operators in Oroville equip boats with both, but use the head line only in emergencies. When using guys only, the digging must be done only from the bottom; while with the spuds the bank may be cut in terraces, and this is sometimes preferable in deep ground. In deep ground when cutting the bank by digging from the bottom up in terraces, or down, there is less danger of injury to the bucket line and cleaner lifting of all gravel if spuds are used. This means that there would be less loss of pay gravel caved down behind where the digger is working, and less loss of time and consequent 32 GOLD DREDGING IN CALIFORNIA. less loss of capacity in yardage. However, several operators state that with a head line instead of spuds in digging deep ground, the dredge may be moved more quickly in case of heavy caving of the bank, and so save accidents. Then, again, the use of the head line gives an easier and more even distribution of the tailings, and, it is claimed, makes the sand pump unnecessary. ILL. No. 19. TAILINGS STACKER, BELT CONVEYOR. The Stacker.— There are two types of stackers in use in California- one the ordinary belt conveyor, and the other an endless chain of buckets. (See 111. Nos, 19, 20, 21.) Usually, the Bucyrus dredges, and other makes except the Risdon, are equipped with belt conveyors, while the Risdon is equipped with bucket conveyors. The belt con- veyor will not work at a higher grade than 18 or 20 per cent, while the bucket conveyor works usually at 35 degrees. The belt of the former must be renewed every six or nine months. This makes the cost of GOLD DREDGING IX CALIFORNIA. 33 ''repairs" considerably more than for the bucket conveyor. However, to otl'set this, there is considerably less loss of time with the belt con- veyor from this cause, for practically the only wearing part is the belt, and when this wears out, a new one can be put in in a few hours. Some of the tables of loss of time and cost of repairs of conveyor give figures so that comparisons can be made, but hardly enough data have lieen kept to figure closely on the dififerenees. ILL. No. 20. TAILINGS STACKER. BUCKET CONVEYOR. In New Zealand a number of dredges equipped with centrifugal stackers are in use. It is claimed for them that the original cost is less, that the weight saves several tons on the boats, that the cost of repairs is less, and that the efficiency is as great as for the belt and bucket conveyors. However, none have been built in California and no definite data are at hand. ]LL No 21. CONTlXrtH'S-BUCKET STACKING LADDER ON " KL DoKAUO No. DRIVEN BY INDEPENDENT MOTOR IN SMALL MOTOR HOUSE ON TOP OF LADDER. LATEST TYPE RISDON DREDGE ILL. No. 22. INDIANA No. 1, OKi)\lI>LK, SHEWING SAND PIMP \VORKIN( GOLD DREDGIXG IN CALIFORNIA. 35 Sand Pumps.— In order to prevent the filling up of the basin in which the dredge floats and eonseqnent interference with its flotation, in many cases at Orovilie it has been found necessary to pump the fine tailings that come from the sluice-box up to the top of the rock pile made by the stacker (see 111. No. 22). As this recpiires considerable power, it is discarded wherever possilile. In deep ground with deep water, it is not required. SCREENS, SLUICES, ETC. The conditions that are most important to be considered in order to ■determine the kind of appliances to use in saving the values are: (1) Size of particles of gold; (2) Shape of the particles, whether nuggety or flaky; (3) Presence of clay: (4) Will the gold amalgamate readily; (5) Amount of black sand; (6) Amount of platinum; (7) Hardness of gravel. Screens. — Two kinds of screens are used in California: the shaking and the revolving. The purpose is to disintegrate the gravel and clay in order to permit the fine material, the values and water to pass through the holes along the length of the screen to the gold-saving tables or sluices below, and convey all coarse material to the stackers, to be carried to the dump piles. As to screens, two main questions must be determined: {a) Whether to use a revolving or a shaking screen; (6) Size of holes in the screen. As to (a), the hardness of the gravel and the presence or absence of clay are the main determining features. If the gravel is a clean wash, comparatively free from clay, such as that at Orovilie and Fol- som, the shaking screen is generally preferred to the revolving screen, mainly because the first cost and the cost of repairs are less. How- ever, there are cases, even in these districts, when some hard pieces of gravel are not disintegrated and the values lost. In case there is any •clay present, it will adhere to the gravel or pieces of bedrock, especially if blocky, or will "ball up" and so carry off the gold. In a shaking screen, bowlders and larger pieces of bedrock will not be turned over so that the water jets will have free play. This is the case especially in such bedrock as most of that along the Yukon, which is often blocky, and carries much gold in clayey seams down to a depth of from one to six feet. Where the gravel is hard, it has little opportunity to disin- tegrate in the length of the shaking screen. A revolving screen with fi-anges and rods across the screen will turn the material over and over, subjecting all sides of it to the force of the water from the jets, and v\'ill afiford a sort of milling process by which the bowlders and smaller 38 noT.D nuKDaiNO ix cat-ifornma. stones arc lifted iii) and thrown down on \\w ]uiii[)s of gravel and clay. Under the favorable conditions existing in the Sacramento Valley districts, the shaking screen is preferred for the following reasons: (1) The effective screening surface is larger; (2) It is easier kept in repair, because the plates are small and conveniently replaced; (3) The gravel drops over a larger surface on the plates below, and so comes the better in contact vv^ith the quicksilver. Then the water from the jets playing down on the screen plays over a wider and thinner surface. In some cases, a combination of the revolving and shaking screeois would be preferred. In this way two screenings could be had. The revolving screen varies in diameter from 3I/2 feet and in leng-fli up to 24 feet. The shaking screen for a 5-foot bucket dredge is in some of the later dredges built in two parts— the first part 7 feet wide and 16 feet long, and the second or lower part, 7% feet wide and 16 feet long. This enables, of course, a much larger sluicing-table space to be employed below the shaking screen. The size of the holes in the screens will be determined by the size of the largest particles of gold. At Oroville aiid other districts in the Sacramento Valley, where all the gold is fine, five-sixteenths and three-eighths inch holes are generally used. Where there is both coarse and fine gold, it must be remembered that with the larger holes, coarse material will have to be sluiced, a greater depth of water will be required in the sluices, and there will be a consequent greater loss of fine gold. To obviate this, it is suggested that smaller holes be used in the upper part of the screen and larger holes in the lower part, and that the finer and coarser material be run into separate sluices. It would not be necessary to have the larger holes in more than four feet, or even less, of the length of the screen. Sluices. — On the dredges in the Sacramento Valley districts, such as Oroville, Yuba, and Folsom, the gold is saved on what are called gold-saving tables (see 111. Nos. 2-1 and 25) and a sluice running out astern of the dredge where the tailings are dumped into the water. The area of these tables is for a 5-foot dredge with shaking screen about 750 square feet and for the sluices about 300 square feet, and somewhat less with revolving screens. This area is somewhat less for the smaller dredges and more for dredges of larger capacity. As it is, generally speaking, all the surface possible is made, and it is limited, of course, to the size of the boat. There can be no question but that much of the finer gold is lost. How much this may be has not been determined, for, no matter haw careful the rocking and pan- ning of the drill samples, the finest gold is not saved. 40 GOLD DREDGING IN CALIFORNIA. It may be said that if some of the finest gold saved at Oroville were shaken vip in a bottle of clear water it will take two hours' time to settle again. Therefore, neither panning, nor rocking, nor any of the present gold-saving devices can save all the gold. One of the best informed men at Oroville, who has been in the industry since the beginning, says that, with the improvements that may in time be made in the gold-saving appliances, it would be possible to save more gold in the dredges than could be shown by the most careful and exact sampling with pans and rockers. In most cases at Oroville and Folsom, the tailings are sampled in order to determine how much gold is being lost. But this sampling is of no value except to show that the sluice-boxes and tables save a large per cent of what could be found by panning or rocking. In other words, very little is found in the tailings, and in most cases practically none at all, by panning or rocking. The quantity of fine gold which goes off in the water should be determined by test, and if it amounts to as much as seems probable, there should be devised a scheme, in connection with the sand pump, for an auxiliary saving appliance that would enable a larger propor- tion of the finest gold to settle. The amount of extra power that would be required and the cost of extra equipment need not be much. Of course, the larger the dredge, the greater the opportunity to save larger proportions of the gold now being lost. There are two classes of sluice and table paving used in the Sacramento Valley gravels to save the fine gold. , One is ordinary Hun- g'arian or cross riffles with quicksilver, and the other cocoa matting covered with expanded metal, 2yo-incli mesh. These are nearly equally satisfactory, so far as the managers report. However, in most cases each manager has used only one kind and made no compar- ison. Where comparison has been made, the preference seems to be in favor of the riffles with quicksilver. There is no arsenic or any- thing else present to prevent a rather free amalgamation. Yet there is present so much black sand which would prevent the gold from reaching the quicksilver that it is found necessary, in putting in the riffles, to insert between them stones that stand up above the tops of the riffles in order to stir up the black sand and allow the gold to go to the bottom. On the cocoa matting, the expanded metal, in diamond shape, about one-fourth iivth deep, is placed for the same purpose. One of the most careful managers at Oroville states: "We originally used cocoa matting on our dredge, but later installed the riffles and quicksilver and increased our gold-saving area 85 square feet, by utilizing the space in the distiiibuting box directly under the GOLD DREDGING IN CALIFORNIA. 41 screen. We are going to ii.se riffles and quicksilver in our new dredge. ' ' Under the screens on the first tables quicksilver in large quantities held in place by riffles is used with a view to bringing the fi-ne gold into contact as it drops from the screens. In this respect, shaking, screens do better work than revolving screens, because they let the fine material down over a larger surface. Both at Oroville and Folsom, and even at Yuba, it has been found that gold— even the very finest gold— if brought in contact with the quicksilver will amalgamate without much difficulty. In Colorado and in Idaho, where there is fine gold, and dredging has been done on rather an extensive scale, it has been found impossible to make any consequential saving of gold vdth quicksilver, owing to the presence of arsenic or something else. The result is that cocoa matting or some similar appliance must be used. It would appear that where the very fine gold amalgamates freely, riffles and quicksilver are preferable to cocoa matting. As platinum does noit amalgamate with quicksilver, there is a greater loss of this metal when riffles and quicksilver are used, than when cocoa matting and expanded iron mesh are used. CREW OF A DREDGE. The following table will give an idea of the number of men commonly rec|uired on dredges. The Avages named are those usually paid at Oroville : Crew for One Dredge. Per Day. 1 foreman, at .fo.W per day |o 00 — $5 00 3 winchmen, at $3.00 to .IS.oO per day 9 00 — 10 50 Sellers, at $2.00 to .|2.50 per day 6 00 — 7 50 1 blacksmith, at . 13.50 per day 3 50 — 3 50 1 helper, at $2.00 to $2.50 per" day e 2 00 — 2 50 2 Chinamen, at $1.75 to $2.50 per day 3 50 — 5 00 Total .. $29 00 — $:34 tX) In addition there is a superintendent, whose time is generally divided among several dredges. The winchmen and oilers work eight- hour .shifts, while the blacksmith and helper work ten hours. The Chinamen clear the ground of brush and trees, "bury dead men," as making fasteners for the lines is called, and do general chores. The depth to which the present dredges may dig is from 30 to 60 feet below the water-level, the latter depth being reached by the new dredges on the Yuba. That greater depths may be reached is only a question of increased strength and power and longer digging ladders. These work at their best, it is claimed, on an angle of 45 desrrees. 42 GOLD DREDGING IN CALIFORNIA. WORKING COSTS. A majority of the dredge companies in California have given statements as to the approximate actual cost of dredging per cubic yard, which will be found in the accompanying folder, and in tables following. These costs vary from 2.36 and 3 cents to as much as 81/2 cents. It will be seen that where a return of 3 cents or less is given, it is for a new dredge with all the advantages of the latest ideas as to strengthening the parts of the machinery, and that there have been no breakdowns and consequently very little, if any, costs for repairs. The labor bill has been very light, for the running time has been full. The owners of this dredge have stated that their costs will be mate- rially increased in working longer periods of time, through the loss in actual Avorking time caused by breakdowns and the cost of new parts and for repairs. So it is only those reports on dredges which have been in operation for a long time, say three or four years at least, that are of much value in determining what would be the average cost of woi'king under sim- ilar conditions. However, one must remember that the lately built dredges are more strongly made and afford less opportunity for break- age and repair costs. The record for low cost is 2.36 cents per cubic yard with a new dredge, as will be noticed in the tables of cost given elsewhere in this bulletin. In studying these reports, one must consider in respect to the different districts: (1) The cos't of power; (2) The rate of wages; (3) Whether the company reporting has one or several dredges under one management; (4) Whether the company has its own machine shop or not; (5) The hardness of the ground, and this particularly as to whether blasting with powder is necessary; (6) The size of the buckets; (7) Whether the buckets are alternating or close-connected; (8) Whether belt or bucket conveyor is used; (9) Whether revolving or shaking screens are used; (10) Whether a sand pump is used; (11) The age of the dredge. Only one company operating at Folsom returns cost of working, and that at 5 cents. At Folsom the cost for power is 0.65 of a cent per kilowatt hour, while at Oroville it is 1% cents. Some idea of the difference in cost per cubic yard between operating one dredge and operating several dredges under one management may be had from the estimate of the Oroville Gold Dredging and Explora- tion Company, and this comparison table, showing the estimated cost of one or three dredges, all under one management. (See tables.) Of course, under certain difficult conditions a dredge of small capacity may be preferable, but under most ordinary conditions, such as at Oroville, Folsom, and other places in the Sacramento Valley, 44 GOLD DREDGING IN CALIFORNIA. the greater the yardage capacity of the dredges, the lower the cost of working. It may be said that the cost of repairs is still excessive, but this item of expense has been reduced from year to year since the first successful dredge was put in operation in 1898. It may be said, too, that if the dredge-builders had not increased the strength of the buckets, the quality of steel used, and in many other ways strength- ened all the straining and wearing parts of the dredges, it would now be impossible to build, as they propose doing at Folsom, a dredge with 13 cu. ft. buckets, or even 7 cu. ft. buckets. A comparison of costs of a new dredge with those of an old dredge of the same size and type is therefore unfair. Whenever the Bucyrus type of dredge is mentioned, it is under- stood to have close-connected buckets, a shaking screen, belt conveyor, and riffles and quicksilver on the sluicing-tables ; while the Risdon ,dredge has alternating buckets and links, a revolving screen, bucket conveyor and cocoa matting, with expanded metal mesh covering them on the sluices. It may be said, however, that the makers provide for the mine owners whatever style of any of these parts they may require. It is for the dredge-builders and for the skilled managers at Oroville or Folsom or elsewhere in the State to more seriously consider this question of cost of repairs than anything else, except, of course. the question of saving the present loss of fine gold, w^hich is far greater than most of them suppose. The following tables (Nos. 1 to 8) are from the annual report of the Oroville Gold Dredging and Exploration Company of San Fran- cisco, for the calendar year 1903 : TABLE No. 1-BULLION TABLE. ^ ^ . Cubic Yards | Cost Tvf„„.i, (BankMerts- Operating per uremeiit) PLxpenses. ; Cubic Dredged. | Yard. January .. February _ . March April May June July August September. October November. December . Totals and averages. *31,000 *30,130 *3(l,570 49,130 35,900 34,040 40,100 46,000 4(;,790 r)(),9tio 39,420 40,570 474,610 1 $30,784 95 ,712 77 ,804 48 ,895 99 ,684 32 ,273 46 ,667 87 ,017 13 ,884 83 ,529 99 ,574 56 ,530 64 ,208 91 CenU. 5.52 5.98 9.47 5.46 6.33 7.83 7.52 8.44 5.34 5.05 6.42 5.45 6.48 *Iii January, February, and March, 44,080 cubic rards of soil were dredged on moving dredge to block 1%. i > :_ o 46 Cost per Yard.... |S= GOLD DREDGING IN CALIFORNIA, ^ ?: S q q o '£ 2 5 o d Per Cent of Total. o 8 ;5S8 ' ^i;5 s s ^ s 2; i5? s cS s 1 1 SSS ^8 S? S S 8 oS ;? g|g 1^ !>! 1 ^ §^ g ^ S 00 35 1 o ^88 88 S S S g ||g ^^ S^. 1 '^ S 8 S 1 1 gS8 SS K i^ ^ S |Si g- 1 i - - 8 8 Jo to ft r^g8 ^8 S Se S 8 ^ S ||| §- '^ g - s s ;^ 8 i 3 SS228 §8 if ?^ S S S5 ill i^ s s ^ ^ -^ JO S3 1 "3 S88 -^S ?? ^ g g i 8 : ^ o C g88 ^a 8 i£ S 12 I^ CO 8 1- i 53^8 88 g § 02 ego coffl ■£ a-. g ?5 t2 8 3 £< s^s §s s ;^ ;s 8 S? g S ?] S 1 III |8 g S 8 8 i* 1 |S8 ^g ^. J 8 ?3 ;1 S 1 5 ^88 S^^ . S' 5 8 CO S ^ 00 ill pl .Pi Ml 1 6J -^- > O oj H GOLD DREDGING IX CALIFORXIA. 47 Table Xo. 2 does not include : Bullion expense 04 Taxes and insurance 38 San Francisco general expenses .17 A total of 0.59 to be added to make up the total of the summary of costs in cents per cubic yard, in Table Xo. 4. TABLE No. 3— EXTRACTION TABLE. Ii:l O, J^ S:' Character of Ground f Dredged. January . February March .__ i!26.7G. 0.49 G. "»:14.7S. 0.43 S. 14.5 S. 14.0 S. 27.2 G. 28.6 28..5 April May .Tuiie July August UA September 30.0 1.29 8. 0.18 S. 0.59 G. 1.06 0.78 0.69 0.68 0.78 0.96 20,8.50 G. ( 10,1.5US. (" 30,130 S. .. 4.400 S. » 26,170 G. s 49,130 j 35,900 34,G10 40.100 46,000 ! 46,790 pr. ct. Cents, o • i i • i 58 5 5'' ^ tight gravel ■ " containing clav. 5.98 Soil. ri 9.47 joil and loose gravel. October 30.7 | 1.03 j 50,960 November 28.1 ' 0.87 ' 39,420 December 26.7 0.94 40..570 Totals and averages 30.4 2 I 173 2 105 1 124 5.46 Soil and loose gravel. 6.33 Soil and loose gravel. 7.83 Soil and loose gravel. 7..52 Soil and loose gravel. 8.44 Soil and loose gravel. 5.34 Soil and loose gravel. worked by Chinese. 5.05 Sand and fine gravel. 6.42 Sand and fine gravel. 5.45 Some Chinese tail- ings. 48 GOLD DREDGING IN CALIFORNIA. ^. » ■* c-i CO l^ CO 3* 1 »-l Total Expense Cl ^ CO ^ (N c ? '-: per Cu. Yd... 1 ^ '- ® 2 g g 8 g IS 1 i 3 ^ s i i i 1 S 1 1 ir< i "' l_l_ .^ >c ^ lO t- a: 05 (M ^ ^ Tf. 1 s § ^ 00 t^ n IN 1 3 s ?i s S5 ^ 1 8 > CD IC CO Tt< CD ^ s Tf S s ^ 1 g ^ g '^ ^ ?5| S M -* 2 fo CO -*< ^ 1 'cS a O c4^ w as- 1 vs- 8? C ^ ^1 g t g cr 1 ^ si S X '^^ t- (N c-f 6^ 1 ^ i S3 « 3 o 3 . 1 ?; S ■* C _i ^ Cf i Cl 00 \r 30 c- ) o; d <» < ^ ^ ■ CO 1 .^ 05 a ^ CD ir 5 M >> t^ s S o ? 1 S o ir t- ^ ^ f^ ~g 00 o J 00 ■ cc ^ CO cr ;-o i^ 00 lO S CD (^ CO I S =» 1 g C bJD s 1 K 1 *" 8 _a G ; o OJ 1 0) c o 3 Q g H O g O -go u 2 o a X O cS s O Ph o o H m GOLD DREDGING IN CALIFORNIA. 49 u1 X — , — .VI '^ — ■M 1 "^ (M CC' ^ iC i-i ci ■i= 1 s R 1 X ^^ 5 H 8 ^ " c^- _A^. ^_ _,^^, , ,_ .^ ~JU^ a; ^8 Si 3^8 ?5 ^ ^.1 15 S^ ^o t^ 00 lO Cl IC o -r 05 1^ IC 'oSS e CDC-1 iCi r CC C-l c-i CC:» ^ 00 CC 05 00 00 §s X ^ C-1 !X (M C-l _• lO^ UOOO o IM "* ^^ ^00 •z ii ^1 ?5 05 1- ift ^ ^"^ ^^ K^ 88 f25 2 i s? S? 28 ??s - -II 5|, 2^ ^ i x-t X 2s -1 _ _ r-^C- 8 X i X X I- X (N IC ^ i~ :c -^ — t-^ So :^ 11 55^ 0^ ^' i ^ ?q? s ^^ 00^ CCC C-IC 05 IC. — 'C TfX >c xx> 1 ,CDiC C-]X >c "O^ ! o:— . ~1 ir t^ IT ^ s i-C — ,— -. ,_ —I iM ' 3 ^iE, C-J^ .c^ c. 1 3 SS 88 £ X > 8 g X S?S 1 12 g S5 05 a: i CO 05 s 52 1 ^ so .^ ^ 10 f- §5 Jg '-' IMX se- ■ 0>-0 23 c CC X ! g -H>C CC(M — ■ (MX! ■05 C ^ ; IC(N I--* 5, CIX 10 X ^ tH I >c IC — 1 01- ! ^^ 01 s ■ CC C-J X CO iC' ' ^' I'-C- t-x ?^ iC O05 1 gr:: irt 1^ >cc 3 i 5e i:; '-C gg s ^n ^ 1 3^ ci SS SS 55 g^ ■r f- -^ t^ ir -S^' -H X iCCC ^^ ic _l_ ?i-t> ccc<- ^^ 05X =fr?i _ 5^ ss 5? 5 ?= 5. i2 X 88 '.r 5 22 —1 X _ — It .J 1- -HX "^ s; " "" ffi X '2 ' 1 ": ; ; i S s 1 , 1 Is "^ l''-"^ 1 . "■ ! ji, ._ U f^ 1 !-> !- 1 rT Si !- bC;H iH 1 1 \ -gi i ■ gi > a i III 5 |js 6 Z 2 1^1 50 GOLD DREDGING IN CALIFORNIA. Aveiago Amnuiil Dredged per Day of 2-lHours Average Amount Dredged per Day of K u n n i II g Time CC -^ ^ T^ "* IC CC' CO ^ n s i Total Dredging Time O 00 o 5 1 l^ t^ t^ l^ x? Total Lost Time - § w h?^' 32 c; o CO Oi -I other Causes - ~ CO IM X! t- » lO o o T-^ ^ (M O-l Clean-ups . o !■- t^ « IC I- CD IM CO t^ CO T-i CD ^ LO gco (M C5 r-; O CD O CO T^i (N CO* C^' CO t- 1^ ^ CI Pumps w CO 9, 05 CO O O O CO O ^ CJ o I- CO 00 '"' CO d '" ^ o CI 00 iH IM ^ 1-1 2 O (M CD O m IM CI o CI t^ CI CO CD a: : CD o CO 00 o Ladder an Bucket Line - .. ■<*i ■* lO 3; ■^_ CO ^ -* c5 ci S ci I CO S in e >> S S ''i ^ ■ <1 cc O ^ P GOLD DREDGING IN CALIFORNIA. 51 TABLE No. 7— SUMMARY OF COST, 1903. (In ct'iits per cubic yariL) One Dredge. Three Dredges. Dredge crew, power, and operating' sui»plies.._ 2.52 2.52 Repairs^-Lahor .98 .48 Supplies 2.65 2.58 Total operating costs 6.10 5.58 Superintendence .38 .16 General expense— Oroville .28 .09 San Francisco .17 .06 Ta xes and insurance .38 .24 I'ullion expense .04 .04 (Jrand total all costs 7.35 6.17 The cost for the same dredge for 91/0 months in 1904 (January 1 to October 15) was: Amount dredged (bank measurement) .'._- .378,890 cu. yds. Cost per cubic yard — Alllabor __.. 2.82 cents Power 1.01 cents All supplies 1.88 cents Total 5.71 cents This does not include about 0.59 of a cent to be added for general expenses, which would bi-ing the total up to 6.30 cents, as against 7.35 cents for 1903. The above work was done with one 5 cu. ft. bucket, close-connected Risdon dredge, with revolving screen and bucket conveyor. It was the intention of the company to build two more dredges. However, one larger dredge is now being built, with the view of handling, with the two, 100,000 cubic yards per month, at a cost, as estimated, of 5.71 cents per cubic yard. 52 GOLD DREDGING IN CALIFORNIA. Since the above was written a record has been made with the new Bucyrus dredge, "Biggs No. 2," of the Oroville Gold Dredging and Exploration Company, which shows a cost considerably below any other similar work in the State, as far as known. In tabulated form the results are shown as follows : TABLE No. 8~REC0RD OF NEW BUCYRUS DREDGE, BIGGS No. 2. For 31 Days, from For 30 Days, from February 26 to March April 1 to April 30, 30, 1905, inclusive. 1905, inclusive. Possible dredging time 31 days 30 days Lost time 119 hours 18 min. 149 hours 55 min. Average actual dredging time per day 20 hours 9 min. 19 hours 00 min. Total amount dredged (bank measurement) 102,630 cubic yards 109,630 cubic yards Amount dredged per day 3,310 cubic yards 3,654 cubic yards Operating costs per cubic yard- All labor 1.16 cents .82 cents Power .... . .39 cents .82 cents All supplies .81 cents .37 cents Other expenses _(__. .. ... 1.34 cents Total 2..36 cents 3.35 cents As to the two following tables from Oroville companies, the general manager says: "We have not been running the Bucyrus machine a j'^ear's time in ordinary diggings, and I am obliged to send you a record of our machine of the Bucyrus type which has been running in very extraordinary ground, and some of the heaviest digging in the Oroville district. This, of course, decreases the capacity of the machine and increases the cost of handling, but it is just as w^ell to have some data from the harder places as to have all conditions favorable, espe- cially for general information that might lead to investment. ' ' In this case the use of powder increased the cost. It will be noted that the Risdon dredge has open-connected buckets and a bucket conveyor, while the Bucyrus has close-connected buckets and a belt conveyor. 54 GOLD DREDGING IN CALIFORNIA. .5^ o ;£—;:: > ^_ 8^ Mbi^- ■-■■r O -^, -. . )Z 1/ ^ 2 5f p ! 03 r o o » ic (M vo 00 a: s: c- Tf r "C i c^i 3; !M ■* ■^_ C-) 30 O C 00 3: « 00 | ^_ i--; -3 1-^ cc a: X -^ ic Ti< Ti5 1~^ r)J ic" I o I CO -T--^ CO 05 -r:^. X I ^ I o — »■ -M — I I lO I rH C-l C-1 C-l IM C-1 !M C-l C-l C-l C>1 I 1X> I (M |S r^ I-- g; i^ p lO c-1 ^ -^ Op Tt< I OOfMOOVOOlC-^lCO:-^ ■* CO vDiC001^XCO(MO"0(M-* IC CO IC ^^ LC — I C -^ (M CO CO (M X |5t 88888888888 SggggggggSSS l8 lg o o o o o o ?n??3 1 a: CD t- CD3:xX'«t*< ^1^ CD cf2 iC O iC LO O C-1 .^ iC O t>1 lO O O © CO -^^ oco^3ioxcoaoox32ao T)o If: S 8 si C « =1-7-^ GOLD DREDGING IN CALIFORNIA. 55 go &^ o;3 '-'

> 32 >^ V ^ S O i S p ^ >J ^o o gl? .P 6.90 6.25 12.82 6.21 5.85 10.28 5.60 5.65 »o6 I OC O^s § o S^g:3?^S2g;2SS§^ „ oi t^ p- i H O. ffcc(Ncqccfcq"ofcc s S W ^1 1 ■ „ _ „ ._ w- ^-1 ,- _t. ^, .V, ^ ^ j^ IC 1 M CO cc 3-. ^ X f~ i; ri T. o Tt< S rr S3 1 — X ^r ■": c Ti -r ~ '^ -f ;c X — o c O ~ X o jt jj ri j: — I- ^J Jj r^ £ 53 w vs- ■ - 1 - 1 - < l^' ^r 1 SF^Sft'SJ§S:5iSiS8 c |g 1 O'lCOXCtOlClCOTf^X'^ i i?§ s •^^ ^ £ 1 ^' i^i^ <: 5 ' S?^gSt^S88^gSaS CO o t; O lO 5 '^ll^fiSil^S^I g s ^ Cs 1-^ 14- " ^r 8SSSSS888888 8 |8 1 g8ggSg88ggg§ S ci is 5fr -r §;e«2S^,xSS?5c'S8 y 1 c t.' K 1 5S2giS3 3?Si-3gigK g 1 S B. o Tt< :c t- X: -* :;: I- --;: X t- I- I- X Ph sr. £ i ^ 1^ « Vi- ^! 8SSSi5^S^3SS 1- t^ s 05 s 1 S P- ^ t^ A S 00 F: I- 1- 1- 1- t? 1 2 1-3 se^ i^h 'g'g -, ^ ,.^ ^ _>. ,^ 00 1- ^ ic ^ :c -* luc •£ r " ■- ~ r '^ 2 2 o I? 5J ^ 1 IS 3^ S-. 3 ■=- t:7: -^-Zttc t^'of x'^vf u'- " 1 C-: ^ Ti X X :- -M Tf ic Tf Tt< ^ "* 'S" o o^ ^ 1 0. .:Sssssssss3!(;s ^ ? O liiisiiiiSiii i § D3 « 1 i c o l2> s 1 1 bo g 1 0} >- ^. .72 7.()!» 8.1!t 8.35 In the following case, the running time, on the basis of 365 days in the year, was sixteen hours in the twenty-four. It Avill be observed that a large percentage of the loss was caused by floods in the Feather River. This, of course, is an extreme case. The figures are for a 5 cu. ft. close-connected bucket dredge. The tumbler loss was owing to not having tumblers on hand : TABLE No. 18. Causes of Stoppage. Belting Bucket line Lines breaking, and changes Cleaning up Per cent l; 23. -.__ 4.i 1. _-__ 5. Conveyor 5.3 Elevating machinery 1.5 Frictions and winches -. 2.5 Oeneral repairs 1-7 High water 15.6 Holidays 1 1-8 Ladder and ladder-hoist. 1-3 Lower tumbler — .- 8.3 Oi 3.8 Power off 4. Shaking screen 4. Stones, roots and stumps 0. Upper tumbler -• 16. Water pump 1- Total 100, The following monthly averages are given as one year's work on three Risdon dredges of different capacity, but all with alternate buckets, revolving screens, and bucket conveyors: TABLE No. 19. Average Time Run per Month. Size of Buckets. Age of Dredge at End of Year. Cubic Yds. Dredged per Month. Cost per Cubic Yard, in Cents. 575 hours. 3cu. ft. 5 years. 31,666 5.86 538 hours. 5 cu. ft. 3 years. 46,032 4.86 558 hours. 4 cu. ft. 18 months. 28,207 8.69 60 GOLD DREDGING IN CALIFORNIA. PROSPECTING AND EXAMINATION OF CONDITIONS. It may seem a simple thing to say that a careful study of all the con- ditions should be made before a dredge is ordered, no matter how large the values in gold may he found to be. The values may in many cases be of almost minor importance, or of no importance, where, as is the case in some of the mountain districts, the hardness of the bedrock, with much of the gold on the bedrock, has prevented dredging very rich ground. There have been many failures in California, and all because proper examination of the ground was not made before the dredges were built. In Trinity County, in one case, a dredge was put in and failed and has been dismantled because the fact that the ground was valueless was not proved. There is another case where a dredge was built and operated for a time on very heavy ground, but it was so weak in con- struction that it failed and was dismantled. Now another company is building a dredge to work the same ground, with every promise of success. There are similar wrecks in the Oroville sea caused by incom- petent pilots. It has been said in regard to sampling, that which will apply to any other part of the examination of a dredging property: "Hap- hazard and occasional sampling and assaying are worse than useless. They lead to great losses of valuable capital, frequently to- the total abandonment of good properties, and, worse than all, to a false sense of satisfaction that discourages improvement by denying its necessity. ' ' Conditions to he Considered.— The following are some of the condi- tions, etc., to be determined by drilling and other examination prior to determining whether the ground may be dredged, prior to estimating costs, and prior also to determining the kind of dredge to be used: Value iu gold por culjic yard, and its dis- Whether l^edi-ock is level or not. tribution. Water— amount of supply, and cost. Hardness of gravel. Cost of power. Total depth of gravel to bedrock. Wages. Depth of gravel from water level to bedrock. Cost of transportation. Whether level or rough on surface. Cost of supplies. Size of bowlders. Cost of repairs. Amount of clay in gravel. Cost of land. Hardness of bedrock. Climatic conditions. Hardness of Gravel. — Generally speaking, any gravel that may be picked may be dug with the dredge, without the use of powder. If it is so hard as to require blasting, the cost per cubic yard will be increased from 2 to 3 cents. Depth of Gravel.— The most satisfactory depth to dredge with some of the newer dredges now in use is not to exceed 60 feet, but they will J -n GOLD DREDGING IN CALIFORNIA. 61 work down to 70 feet. In order to work to a greater depth than 70 feet, some changes in the digger, stacker, and power would be required. Level Surface of Gravel.— With an uneven surface the use of head- lines is not so satisfactory as spuds. Size of Bowlders. — Very large bowlders can not be handled with the ordinary dredge, and much gravel may be left on the ground. The size of the bowlders must be considered also in deciding whether to use an open or close connection of buckets in the digger, the latter rendering it impossible to handle the larger bowlders. Climatic Conditions. — Of course, freezing weather will prevent wash- ing the gravel, and cause a stoppage of work. In the northern latitudes of Montana and Alaska, the season is commonly not more than five months long. Clay in Gravel. — The clay will not permit of clean dumping from the buckets, and not only is much gold carried back to the bottom and lost, but the yardage capacity of the dredge is decreased. Besides this, the clay carries off gold and fine amalgam from the sluice-boxes. Hardness of Bedrock.— li the bedrock is too hard to dig, gold in the crevices or lying near the bedrock is lost. The drill will locate the position of the pay which may not be too close to the bedrock. Level Bedrock. — The bedrock should be near enough level to permit the boats to float over all the ground to be worked. Presence of Arsenic— The presence of arsenic or anything else that will prevent free amalgamation makes the use of quicksilver and riffles of little avail, and cocoa matting, plush, or other such means must be adopted to save the gold, especially where it is in fi-ne particles. Drilling.— 1^ early all this work in the Sacramento Valley districts of California has been done with Keystone drills. No. 3 traction. Owing to the presence of water in the gravel in most instances, it has been found impracticable to sink shafts. The cost of the drill, including freight, etc., is about $1,900 complete. Three men are required to work it, w^ith wages from $3.50 to $4.00, and $2.50 and $2.00 per day. To this must be added the cost of fuel, water, repairs, etc., and wages of one or two men to do the sampling. The sampling, if properly done, would require a skilled man, and his pay might add much to the cost. The total cost per day to run the drill and do the sampling varies from $15 to $30. About 12 or 15 feet per day is a good average speed for sinking in the gravels of the Sacramento River basin. With larger bowlders and harder ground the cost might be materially increased. ILL. No. 29. KEYSTONE DRILL AT WORK AT OROVILLE TO PROSPECT FOR THE VALUES, AND DETERMINE CHARACTER OF THE GRAVEL. GOLD DREDGIXG IX CALIFORNIA. 63 In comparatively shallow ground, where there is not much water, it is much more economical to sink shafts than to drill, and the results will be found more satisfactory. By proper sampling is meant the determination, from a compara- tively small sample, of the values in a much larger volume of the same material. Care, judgment, and experience are necessary, and all such work, whether done by drilling or by sinking shafts, should be put in charge of an experienced man. Gravel lifted by drills or taken from a shaft must ])e accurately measured or weighed, and proper allowances made for expansion when loosened. Allowance must be made for excess of bowlders not sampled, and for excess of gravel beyond the normal width of the drills that may come in and be lifted. Prospecting. — There is no rule as to the number of holes that should be sunk. ]\Iore drill holes would be required, to give satisfactory results, than shafts. If the values are comparatively evenly distrib- uted over the tract to be examined, fewer holes would enable nearer approach to a correct estimate of values than where the pay is uneven. In districts where the character and values are comparatively well known in parts of the gravel that have been sampled, less careful examination i>s necessary on intervening tracts in order to determine most of the conditions and even the values. Errors in Sampling frequently occur from the squeezing in of material around the bottom of the casing, so that more gravel than is called for by the size of the hole is lifted. A check on this is to drill and pump in a section of a foot or so and weigh the material. Sliming and consequent loss of gold sometimes result when too long a period of churning transpires before pumping the hole. The casing should be kept driven below the point of drilling, when- ever possible. Fi)if 6'o?f/.— AVhen the gold is as fine as at Oroville or Folsom. the pan and rocker will not save all of it, but will save all that the best saving tables in the dredges will save, and may save consid- erably more. But when it is considered that if some of the finest gold now being saved be shaken up in a bottle of clear water it will take one or two hours to settle, there can be no question that some is lost whether the sampling is done by panning or rocking, and also in the sluicing. How much this is could be determined by gathering samples, especially of the water from the pans and rockers and also at the ends of the sluices and subjecting them to proper tests. It would seem that this work should be undertaken and carefully carried out by the dredge people. If much gold is being lost, there is a spur to ino-enuitv in devising means for saving it. 64 GOLD DREDGING IN CALIFORNI. JVl, JV'S. So// 0'-4^' f/ne Grat^e/ -^ -e'^ Coarse Grave/ ei- ySanc/ /6-eo' fineGrai/e/ 20-2/' Coarse Gra\/'e/ - makes return of cost of working at 7 cents per cubic yard. (See III. No. 40.) Pemisylvania Dredging Company, Sam W. Cheyney, manager, San Francisco. In Sec. 25, T. 19 N., R. 3 E. Area of holdings, 152 acres. This company began operations in October, 1902, and has worked 25 acres. Its dredge was built by the Golden State and Miners' Iron Works of San Francisco, with buckets of 5 cu. ft. capacity. The aver- age horse-power consumed is 140. The cost of the dredge was $70,000. The average number of cubic yards dug per month during the year 1903 was 43,830. The cost of dredging is returned at 8I/2 cents per cubic yard. This dredge has a different system of screening from the others in the district, in that there are two screens used, one above the other, of the shaking screen type. In the upper screen the holes are l^^ inches in diameter, and in the lower screen 14 iii^h in diameter. (See 111. Nos. 41 and 42.) Butte Gold Dredging Company, B. Noyes. secretary, San Francisco. In Sec. 7, T. 19 N., R. 4 E. Area of holdings, 85 acres. This com- pany began operations November 26, 1902, and has worked 15 acres with one Bucyrus dredge, of 31/0 cu. ft. bucket capacity. The cost of the dredge was $50,000. The horse-power consumed is about 80. The actual average digging capacity of the dredge for the first thirteen months of its operation was 47,640 cubic yards per month. The owners return the average cost of the digging and all other expenses at 7 cents per cubic yard. American Gold Dredging Company, F. S. i\Iayhew, secretary, San Francisco. Area of holdings, 275 acres. The company began opera- tions in November, 1902, with a 3 cu. ft. Bucyrus dredge, and has since built a 5 cu. ft. bucket dredge of the same type. The digging capacity of the 3 cu. ft. dredge is returned at 45 cubic yards per minute. The return of the actual average dug by the 5 cu. ft. bucket is 90,000 cubic yards per month for the first six months, and the cost of digging during that period, including all expenses, such as office, management, etc., is placed at 3 cents per cubic yard. These figures are, of course, unusual both as to the yardage and as to the cost per cubic yard. The ±:-^Ta 80 GOLD DREDGING IN CALIFORNIA. company was reluctant to give out these figures unless it would be stated that during the six months' running there were no breakdowns, and consequently no cost for repairs; also, that there was so little loss of time that this large yardage was made possible. The cost of the 5 eu. ft. dredge was $70,000, and the average of the horse-power con- sumed, 100. El Oro Dredging Company, B. Noyes, secretary, San Francisco. In Sees. 17 and 20, T. 19 N., R. 4 E. Area of holdings, 220 acres.' This company began operations in December, 1903, and has worked five acres. Its dredge was built by the Link Belt Machinery Company, of ILL. No. 41. PENNSYLVANIA GOLD DREDGING COMPANY. Chicago, with buckets of 5 cu. ft. capacity, close connected. They claim an average capacity of 75,000 cubic yards per month. In respect to screens, sluicing table, and stacker, it is similar to the Bucyrus type. The company proposes to build another dredge. (See 111. No. 43.) James H. Leggeti, Oroville. In Sec. 18, T. 19 N., R. 4 E. Area of holdings, 70 acres. Mr. Leggett began operation's March 31. 1904, with a Risdon dredge of 5 cu. ft. bucket capacity. He returns the average digging capacity as 45,000 cubic yards per month. The horse-power is placed at 100, and the approximate average cost of dredging per cubic yard at 5 cents. Five acres have been worked. (See 111. No. 10.) 82 GOI.D DREDGIXG IX CALIFORNIA. Vilofo Syiulicate, JJinittd, J. W. Pew, secretary, San Francisco. In Sees. 19 and 30, T. 19 N., R. 4 E. Area of holdings, 200 acres. This company began operations November 1, 1904, with one dredge of the Bncyrus type, 5 cu. ft. bucket capacity. As they have only lately begun work, no returns as to capacity are available. (Seie 111. No. 44.) Ovoville Gold Dredging and Exploration Company, C. 11. Munro, manager, Oroville. In Sees. 24 and 25, T. 19 N., R. 4 E. Area of hold- ings, 600 acres. This company began operations in April, 1902, with a Risdon dredge of 4 cu. ft. bucket capacity, and in 1905 also started ILL. No. 43. EL ORO DREDGING COMPANY'S DREDGE, OROVILLE. LINK DREDGE MACHINE COMPANY'S TYPE. working a new Bueyrus dredge (Biggs No. 2) with 5 cu. ft. buckets. This latter dredge has a record of 109,630 cubic yards dug for thirty days from April 1st to April 30th inclusive. Details of the work and its cost are given elsewhere in this Bulletin, as are details of sizes, etc., of both dredges. The very full tables of costs of operations were pre- pared by Mr. Munro. (See 111. No. 11.) Boston and Oroville Mining Company, William P. Hammon, man- ager, Oroville. In Sees. 13, 23, and 24, T. 19 N., R. 3 E., and Sees. 17 and 18, T. 19 N., R. 4 E. Area of holdings, 650 acres. This com- pany began operations in July, 1901, and has worked 100 acres of GOKD DREDGING IX CALIFORNIA. 83 ground. Three dredges are operating', two of the Risdon and one of the Bueyrus type, each of 5 cii. ft. bucket capacity. The cost of equip- ment was $175,000. Revolving screens are used in the Risdon dredges, and shaking screens in the Bueyrus. However, in all these dredges Hungarian riflfles and quicksilver are used in preference to cocoa mat- ting and expanded metal. It will be seen that this is also true of the dredges owned by the Boston and California Dredging Company and indicates the preference in the district for riffles and quicksilver over the cocoa matting, and a belief that where there is no arsenic or other material to prevent the free amalgamation, the riffles and cpiicksilver ILL. Xu. U. VILORO DREDGE. OROVILLE FIELD. LATEST TYPE OF BUCYRUS DREDGE. will save more of the fine gold than will the matting. The company proposes to build additional dredges. (See 111. Xos. 45 and 46.) Boston and California Dredging Company. AVilliam P. Hammon. manager, Oroville. In Sees. 18 and 19, T. 19 X.. R. 4 E. Area of holdings, 300 acres. Operations were commenced in Alarch. 1902, and about 60 acres of ground have been worked. The company is operating three dredges, all of different types— one being a Risdon, with open-con- nected buckets and a bucket conveyor : one a BucyriLS dredge, with close- connected buckets and belt conveyor, and the third a Clarion Steam Shovel Company dredge, with continuous chain buckets, similar to 86 )M) DHKIXilXti IX CALIFORNIA. those Oil the others, close eonueeted. 'J'he iiuuiageiueiit's returns of the digging: capacity of these dredges are: for the Eisdon, 45,000 cubic yards; for the Bucj-riis, 60,000 cubic yards; and for the Marion, 90,000 cubic yards per month. It may be stated here that if it were not that the dredges were built in the order named, so that the last built had advantages over the others in stronger construction, there would not be so much difference in the yardage handled. Then, again, it may be said in favor of the Risdon dredge that the horse-power is less. However, it may be said in regard to the IMarion that the company claims that the construction of the screen enables the washing of larger ILL. No. 47. "CALIFORNIA No. 3," BOSTON AND CALIFORNIA DREDGING COMPANY OROVILLE. BUILT BY MARION STEAM SHOVEL COMPANY. quantities of gravel than do the other screens, and in this way permits a larger amount of gravel to be handled. A number of the managers at Oroville have stated that the sluicing capacity or the gold-saving- capacity of the dredges was not sufficient to handle all the gravel that might possibly be raised. The screen on the Clarion dredge is of the revolving type, somewhat conical in shape, growing smaller with offsets toward its outlet. These offsets, together with crossbars, retard the progi'ess of the gravel sufficiently to insure perfect washing. How- ever, the washing capacity, it is claimed, was increased fifty per cent. (See 111. No. 47.) ILL. X... 4',». FROXT VIEW OF MARIiioLD CoMPANVS DKKI>i>l". AT uROVILL 88 GOLD DREDGING IN CALIFORNIA. Marigold Dredging Company, J. W. Goodwin, president, San Francisco. In Sees. 30 and 31, T. 19 N., R. 4 E., and Sees. 25 and 36, T. 19 N., R. 3 E. Area of holdings, 467 acres. Operations were commenced on this property in Jannaiy, 1900, with a 3 cu. ft. bucket Risdon dredge. Tliis company is now operating one 5 cu. ft. Risdon dredge. The extent of ground worked is 50 acres. (See 111. Nos. 48, 49 and 50.) . Feather Valley Gold Dredging Company, C. Jackson, manager, San Francisco. In Sees. 4 and 5, T. 18 N., R. 3 E. Area of holdings, 220 acres. This gi'ound was lately purchased and was drilled. YUBA DISTRICT. In this district no dredging was done until August, 1904. The two dredges built by the Yuba Consolidated Gold Fields Company are doing contract work for the Government retaining dams. They are thus making their tailings of value. There is only one company actually operating, but other lands have been drilled and it is estimated that there are 5,000 acres of gravel suitable for dredging Prospecting.— This w^as done with drills. Values. — The gold is comparatively evenly distributed over the district. Estimates place the values at from 15 to 35 cents per cubic yard. As the gravel is much deeper than that in the Oroville district, a very rough estimate, without much data to go on, of the probable total yield of this district would be $50,000,000. Gravel.— The depth of the gravel in this district is greater than in any other in California, the Yuba Consolidated Gold Fields Com- pany digging to a depth of 60 feet. It is a loose, clean wash, free from clay, and contains no large bowlders. The dredges in operation use close-connected buckets. Bedrock.-The false bedrock to which the gravel is dredged is comparatively flat and very soft— a volcanic ash, wdth sand doubtless overlying other gravels. Poifer. — Electric power is used. Lahor.—The wages paid on the dredges are $4 for winchmen and $3 for laborers. Higher wages are paid than at Oroville, in order to obtain more efficient men for larger and more expensive clredges. Transportation, Sapplies. efc— Rail facilities to ]\Iarysvil]e are srood, and a better wagon road is being built to the tract. ,J2 ;,^ t-M:^ ^ !! yC^r- •;TArKP:R KXrrOF MARIGOLD COMPANY'S DRKDGK AT OROVILLE. ILL. No. 51. YUBA COXSOLIDATED GOLD FIELDS' DREDGES. EACH OF CU. FT. BUCKET CAPACITY. BUCYRUS TYPE. GOLD DKEDGIXG IX CALIFORNIA. 91 6'o/(/. — Tlie gold is very fine. As much as 20 per cent will pass through a 150-mesh screen. It readily amalgamates, the dredge nsing riffles and quicksilver. The value is about $18.50 per ounce. Ideal Co;((?(7/o»s.— Practically all the conditions are ideal for suc- cessful and economical dredging. Yiiha Consolidated Gold Fields, Newton Cleveland, manager, ]Marysville. In T. 16 X., K. 5 E., ten miles east of Marysville, on the Yuba River. Area of holdings, 3,000 acres. This company began operations in August, 1904, and has a contract from the Federal Gov- ernment for building a retaining dam at that point. Two dredges of the Bucyrus t^^e of 6 cu. ft. bucket capacity are now at work. The company has contracted for four more dredges, and a number of others are contemplated. The cost of the tAvo dredges now in opera- tion was about $200,000. Shaking screens, Hungarian riffles with quicksilver, and belt conveyors are used. It is notable that in this district these dredges are digging to a depth of 60 feet, which is more than 50 per cent greater than the depth of the gravel in the other Sacramento Valley districts. These dredges, which are new, are lifting 90,000 cubic yards per month each, with 200 horse- power. (See 111. Xos. 51 and 52.) BEAR RIVER DISTRICT. .Irta.— About 1.000 acres of gravel on the Bear River near Wheat- land have been drilled systematically and proved of sufficient value to dredge. Gravel. — The dei)th of the gravel averages about 30 feet. It is all a clean wash, free from clay and with no large bowlders. Bedrock. — This is volcanic ash. similar to that at Folsom and Oroville. Poiver.— There is electric power available, at a cost similar to that at Oroville, namely, l^/o cents per kilowatt hour. Wages.— Yor winchmen and laborers, this will be about $3.50 and $2.50 per day respectively. Transportation, Supplies, etc. — There are convenient rail facilities with San Francisco, and the neighboring farming country is a source of supplies. Gold. — The gold is comparatively very fine, twenty per cent of it impalpable, and in value about $18.50 per ounce. 92 GOI.D DREDGING IX CALIFORNIA. Conditions. — All the conditions are as favorable as those at Oroville, and very similar. Bear River 3Iining Company, subsequently called Bear River Exploration Company, R. D. Evans, Boston, Location, near Wheat- land. Area of holdings, 1,000 acres. There are four Risdon dredges, two of which began operations in July, 1900, and the other two began in 1902. The first two have 3i/4 cu. ft. buckets, and the last two 4 cu. ft. buckets. The latter have a capacity of 50,000 cubic yards per month. The gravel runs from 40 to 50 feet in depth, and has some clay with it. Details of dredges are given in the large table accom- panying this Bulletin. FOLSOM DISTRICT. There are in this district five companies operating eight dredges, none of which use less than 5 cu. ft. buckets. The largest dredge has buckets of 13 cu. ft. capacity. Starting later than the operators at Oroville, they have made use of w^hat has been learned there, and discarded all small dredges. The work is in the hands of people with plenty of capital and skilled engineers. One of the companies has a machinery plant larger than any other in California, outside of San Francisco, and is prepared not only to do its own repairing, but also to build its own dredges. This, of course, means a large saving of cost in repairing, and it indicates how companies with large areas to be worked and many dredges employed may very largely reduce the cost of dredging. Area. — The Folsom district, as it is called, extends from the town of Folsom to a short distance below the Fair Oaks bridge along the American River, a branch of the Sacramento, and in Sacramento County a distance of six miles, or a little more. Most of the gravel is on the south side of the river, and is in width, generally, from 1 to 114 miles. The area of the gravel that has so far been acquired by the company, after investigation, is about 5,000 acres. Prospecting.— VYSiCtlcullY all the prospecting of these gravels has been done with drills, there being too much water in the ground to permit the sinking of shafts. Values.— Tl\Q gold is comparatively evenly distributed over the dis- trict, and the results of the drill samples indicate that the gravel will average from 15 to 25 cents per cubic yard. Taking the depth of the gravel as 10 yards, this would make the probable yield over $40,000,000. Gravel.— "Yho. depth of the gravel is from 16 to 50 feet, and in this respect varies more than does that at Oroville, because it is not spread GOLD DREDGING IX CALIFORNIA. 93 over as wide an area. The average is about 30 feet. The gravel is all a very clean wash. In this connection it may be said that shaking screens are used instead of revolving screens in all except one dredge. There are no large bowlders to interfere with digging, and it may also be said that with the exception of the one dredge, all the buckets are close-connected. Except on some of the higher benches, where there is cement, there has been no need to use powder for blasting. Bedrock.— The bedrock here, as at Oroville, is a volcanic ash, or false bedrock, which may be dug without difficulty, and under which there is probably other gravel overlying the real bedrock. Poiuer. — Electric power is used in all cases, at a cost of 0.65 of a cent per kilowatt hour. This is against II/2 cents per kilowatt hour paid at Oroville, or less than one-half— an important consideration in the working costs. Water. — There is an abundance of water, supplied at low rates. Labor. — Experienced labor is easily obtained, the wages being usually $5 for foremen, and $3 and $3.50 for winchmen. Other laborers are paid from $2 to $2.50. Transportation, Supplies, etc. — There is a railroad into the district. The source of supplies is San Francisco and Sacramento, with low rates of freight. Gold. — The gold is comparatively very fine in size of particles, and the size of holes in the screens is usually three-eighths of an inch, as at Oroville. The mint value of the gold is about $19 per ounce. Conditions. — Taking all things into consideration, the conditions are ideal for economic working. Agriculture. — Not over one-half of the 5,000 acres of dredging ground in the Folsom district is of any value for agriculture. The value of the rest of the ground could not be placed at more than $100 per acre, or a total of $250,000 for the whole tract. The yield in gold from this district will exceed $40,000,000, according to the estimates of values made. The value of this gold to the State at three per cent per annum would amount to more than four times as much each year as the total value of the ground for agriculture. Then, of course, it may in time be reclaimed for agriculture, as lands of that character become more valuable. Debris. So far there has been no dredging in the river and no debris whatever has been sent down by these dredges. In time, the river bed may be dredged, but, as at Oroville, this can be done without detriment. GOLD DREDGING IX CALIP^ORNIA. 95 companip:s operating. The AshhuHoii Mlniiifj ('oiiip<(iiy, Robert E. Cranstou, mauager. Sacramento. In Sees. 5. 6, 7, and 8, T. 9 X., R. 7 E., American River District, Sacramento Connty. Area of holdings, 310 acres. This company began operations ^Nlarch 1, 1899, Avith a dredge that was bnrned May 25, 1903. Its new dredge, made by the company at a cost of $120,000, of the Bncyriis tjTDC, has not been long in operation, but the cost per cnbic yard for Avorking is estimated at more than 5 cents. Another dredge Avill be Ijiiilt. The area of ground worked is 20 acres. (See 111. No. 53.) ILL. No. :>i. "EL DORADO No. 1," FOLSOM FIELD. LATEST TYPE OF RISDON BOAT. [Began operations May 1, 1905.] El Dorado Gold Dredging Company, E. H. Benjamin, secretary, San Francisco. In T. 9 X., R. 6 E., and T. 9 X., R. 7 E., American River District, Sacramento Connty. Area of holdings, 550 acres. This company has prospected its ground with drills and is now operat- ing a Risdon 7 cu. ft. bucket dredge. Began operations April 25, 1905. (See 111. Xo. 54.) Colorado-Pacific Gold Dredging Company, O. B. Perry, manager. In T. 9 N., R. 7 E. Area of holdings, 200 acres. Has two dredges, the first of which began work in April, 1899, and the other in 1902. Both are. of the Risdon type ; one with buckets of 3i/4 cu. ft. capacity, 98 GOLD DREDGING IN CALIFORNIA. and the other 5 en. ft. The smaller machine has a capacity of 35,000 i'ul)i(' yards per month; the larf^e one averages 60,000 cubic yards per month. This company is working in hard ground, for which reason one dredge is being rebuilt. (See 111. No. 55.) Folsom Development Company and Syndicate Mining Company. (Both companies under one management.) [All information, even in such simple matters as capital stock of corporations, acreage of hold- ings, etc., refused by the manager— the only instance of the kind in the State. Lewis E. Aubury, State Mineralogist.] (See 111. No. 56.) CALAVERAS COUNTY. So far there is being exploited and considered in this county one small tract of ground, which is described in the folloAving paragraph, and at prasent no other lands in the county ai-e being considered with a view to dredging. Calaveras Gold Dredging Company, C. M. Derby, manager, Jenny Lind. In T. 3 N., R. 10 E., M. D. M., on the Calaveras River. Area of holdings, 350 acres. This company began operations in February, 1904, with a Bucyrus dredge of 5 cu. ft. bucket capacity. Electric power is used. The cost of the plant is $75,000. Wages are $3 for winchmen, and $2.50 for laborers. The average depth of the gravel is 35 feet, and it is a clean gravel wash, free from clay, with a few large bowlders. The bedrock is a volcanic ash similar to that at Folsom and Oroville. About 8 acres of ground has been worked. PLUMAS COUNTY. In Plumas County, so far as prospecting has developed, about 1,500 acres of dredging ground has been proved. SHASTA COUNTY. There are two dredges at work in Shasta County, both near Redding, and described in following paragraphs. The holdings of these two companies amount to 1,096 acres. Along Cottonwood Creek and its tributaries are large areas which are being considered, amounting to 3,000 or 4,000 acres. Some drilling has been done, but very little of this area has been proved of value. The gravel in the Cottonwood country and the bedrock are similar to that at Oroville, although the gravel Ls generally shallower. On Clear Creek an additional 2,000 acres is being considered. (See 111. No. 57.) No estimates of values were given by the Shasta owners except by the Detroit and California Mining Company, who report a recovery of from 25 cents to $1.50 per cubic yard in Clear Creek. GOLD DREDGING IX CALIFORNIA. 99 As to power, it may be said that the Huron Submarine Alining and Construction Company uses steam, with crude oil for fuel, at a cost of $3 per horse-power per month, while the Detroit and California Mining Company uses electric power at a cost of $5 per horse-power per month. Huron Siihmarine Mining and Construction Company, G. A. DuBois, manager, Redding. In Sec. 25, T. 32 N., R. 5 W. Area of holdings, 396 acres. This company began operations in the Sacramento River, three miles above Redding, and opposite the mouth of Middle Creek. ILL. No. 57 THE B?:DR0(K of the SACRAMENTO RIVER AT MOUTH OF MIDDLE CREEK, ABOVE REDDING. The average depth of the gravel is from 8 to 25 feet. It is blue gravel with many bowlders. The gold is coarse and well worn, and worth about $19 per ounce. The bedrock is of igneous series, very rough. The dredge is unique, having neither buckets nor shovels. It was built by the company on its own plans. The boat is 65 feet long, 24 feet wide, and draws 2 feet of water. A 75-horsepower engine operates a rock pump, air compressor, and auxiliary machinery. Oil is used for fuel at $1.17 per barrel, making the cost of power about $3 per horse-power per month. At the center of the boat is a steel shaft made with sections for extending to any required depth. Each section is boat-shaped. 8 feet wide, 6 feet high, and lli/o feet long. (See Illustra- 100 GOLD DREDGING IN CALIFORNIA. tions Xos. 58 and 59.) The sharp end of these sections heads up stream, ihns ciittino' the water. The lower sections are cylindrical, the lowest being provided with a water-tight door for ingress and egress of divers. This shaft is sunk through water and gravel to bedrock gravel, 25 leet deep being worked in November, 1904. Down the shaft extends the 10-inch column of the rock pump, and a 2-inch rubber hose to convey water under 100 pounds pressure to the mouth of the pump column. A diver in the shaft with the hose in hand works with freedom, direct- ing gravel to the mouth of the pump, and with the pressure cleaning the gold from crevices. The capacity of the pump is 1,500 cubic yards per day, and sufficient water to wash' the gravel in the sluices. The divers receive $125 per month, working five hours each day, and can remain under water that length of time without coming to the surface. The cost of the plant was $110,000. Four men are required for a crew. The company estimates the cost of dredging at 3 cents per cubic yard. They express an intention of building another dredge of a larger size. Detroit and California Mining Company, T. R. Heintz, president and manager, Redding. In Sec. 36, T. 31 N., R. 6 W., and Sec. 31, T. 31 N., R. 5 W. Area of holdings, 700 acres. This company was organized and began operations in the summer of 1900 on a flat in Clear Creek caiion, which formerly had been a lake-bed. The bed- rock at present laid bare is a false one, under which probably other gravel will lie on the true bedrock. The gravel, which is 20 feet deep, is a loose, clean wash, with a few large bowlders. The gold is coarse and well worn, and nearly 950 fine. The owners state that the value in gold per cubic yard is from 25 cents to $1.50, with a little platinum. Prospecting was done by sinking shafts. The dredge was designed by the manager, T. R. Heintz. The gravel is raised on the principle of the hydraulic elevator, the water being forced through the suction pipe by a centrifugal pump, and with the gravel is conveyed in a stave pipe to a 5-foot sluice paved with blocks. There are two undercurrents at the end of the sluice. The manager estimates the average cost of dredging at 5 cents per cubic yard. The average horse-power consumed is 750, at a cost of $3,750 per month. However, the amount of gravel handled is placed at 5,000 cubic yards each twenty-four hours. The cost of the plant is $100,000. CURRENT BREAKERS AND CAISSONS OF THE HURON SUBMARINE MIN- ING AND CONSTRUCTION COMPANY AT REDDING. ILL. No. 59. THE HURON SUBMARINE MINING AND CONSTRUCTION COMPANY' CAISSON DREDGE ON SACRAMENTO RIVER, ABOVE REDDING. 102 GOLD DREDGING IN CALIFORNIA. TRINITY COUNTY. The only dredge iu operation is at Trinity Center, on gravel bars adjoining the Trinity River ; but considerable areas of gravel have been located on bars along the river with a view to dredging. Of this, nearly 2,000 acres are owned by two companies— one operating and the other proposing to build a dredge. There are along the river many bars that probably contain sufficient values, but a majority of them are too small for the cost of a plant. Prospecting.— All the prospecting has been done by sinking shafts. ILL. No. «). THK GALVLX GOLD DRED(;ING COMPANY COUNTY. )F WKAVKRVILLE, TRINITY Values. — The values are not evenly distributed, but in the best areas are fair. In most cases 15 cents or more is claimed. Gravel.— The depth of the gravel varies from about 15 to 25 feeft. It is a clean wash, comparatively free from clay. The bowlders are large in places, but there are not enough of them to interfere mate- rially with the work. (See 111. No. 61.) Bedrock.— The bedrock is slate, usually hard enough to interfere with the saving of coarse gold. Pother. — Steam. Waier.— Abundant. 104 GOLD DREDGING IN CALIFORNIA. Labor.— y^^'uu-hnu'u, $:{ lo .^4; lahoivrs. $2.r)() to $:i. TranspoHaiion.—'By team from Redding'. G'oid.— The ^old is coarse, a.s is also the phitinuni, of whicli there is considerable. In the dredge at Trinity Center, one-inch holes are used in the screen. There has been dredged about 83 acres. The problem in Trinity County, as in Siskiyou County, is to devise a means of cutting the bedrock or cleaning it. A large proportion of the coarse gold is on the bedrOTK, or in it in crevices. Excepting in spots, this can not be dredged by the bucket dredges without a great deal of breaking down of parts. ILL. No. ti2. THE POKER BAR DREDGE, TRINITY COUNTY. RISDON TYPE, 8^ CL. FT. BUCKET CAPACITY. COMPANIES OPERATING. Alta Bird Mining and Dredging Company, Clary, Payne & Kiernan, Trinity Center. In Sees. 32 and 33, T. 37 N., H. 7 W., and Sees. 4 and 5, T. 36 N., R. 7 W. Area of holdings, 687 acres. This company began operations April, 1901, and has worked 5 acres. It has one 31/2 cu. ft. bucket dredge (Urie, Kansas City, make), and contemplates build- ing another, or putting in a hydraulic elevator. Trinity Gold Dredging Company, H. G. Comstock, secretary, San Franci>sco. In T. 33 N., R. 9 W. Area of holdings, 1,100 acres. On this property a dredge worked 30 acres and was dismantled, not being strong enough. A 5 cu. ft. Monarch bucket dredge is now proposed. GOLD DREDGING IN CALIFORNIA. 105 SISKIYOU COUNTY. There are in Siskivou County three mines being worked with livdraiilie elevators-two successfully in the Oro Fino district and one in (Quartz Vallev. One Risdon dredge is working at Callahan, on Scott River A Clipper dredge has been worked at Hawkmsville, but is not now in operation, and one on the Klamath River, which is also \s in nearlv all cases in the mountain districts of California, the bedrock is harder than in any of the Sacramento Valley districts, such as Oroville, Yuba, and Folsom. It has so far been found almost impos- sible to work bv dredging, for the hard bedrock prevents the clean saving of the Amines, and breaks the bucket and other parts of the ladder. • ■, -, ■ -^^ The values are in manv cases very high, but as the gold is usually coarse much of it lies on the bedrock. So far, hydraulic elevators seem to do the best work wherever there is not too much water to prevent cleaning the bedrock. The area of gravel in this county now being worked or under consid- eration bv the elevators and dredges amounts to about 2,000 acres, but there is much more that would be exploited if more successful methods of operation could be devised. COMPANIES OPERATING. ^Ynght & Fletcher. H. D. AVright and Mrs. C. D. Frye, Fort Jones. In Sec 18, T. 43 N., R. 9 W. In the Oro Fino Mining District. Area of holdings, 200 acres. This company began operations in 1890, and has worked 20 acres of ground. The values are not given. In depth the oravel is from 20 to 60 feet, and consists largely of basaltic angular fragments. There are no bowlders. The bedrock is soft schists. Laborers are paid $2.50 per day. The gold is mastly fine and worth i^l6 per ounce. This mine is being worked with an Evans hydraulic elevator, with an outlet pipe 20 inches in diameter. The lift is 20 feet. The pressure pipe is 11 inches in diameter, with a head of 11 feet. The flume is 3 feet wide, with block paving. EasiUck & Gardner. L. Eastlick, of Fort Jones, and S. Gardner, of Greenview. In Sec. 17, T. 13 N.. R. 9 W., in the Oro Fino Mining District Area of holdings, 25 acres. This company began operations in 1890 and has worked 8 acres. The values are not given. In depth the -ravel is from 25 to 40 feet, and consists largely of schist and porphyrv in fragments which are not much rounded. There are no bowlders. The bedrock is mostly soft slate. Laborers receive $2.o0 per day. The ^old is mostly fine and worth $16.25 per ounce. J 106 GOLD DHEDGING IN CALIFORNIA. This mine is being worked with two Evans elevators. One has a 22-inch outlet pipe, a lift of 32 feet, and a 15- inch pressure pipe with a head of 300 feet. The other has an outlet pipe 13 inches in diameter, the lift is 32 feet, and the pressure pipe is 13 inches in diameter with a head of 300 feet. The flumes are 24 inches wide, with block pavements and Hungarian riffles. Porters Bar Dredging Company, J. R. Wade, gen- eral superintendent, Calla- han. In Sees. 6, 7, and 17, T. 40 N., R. 8 W., below Cal- lahan, on Scott River. Area of holdings, 1,000 acres. The dredge of this company has been at work in the Scott River, below Callahan, for a number of years, but was purchased by the present company in the summer of 1904, when it also acquired larger holdings below the present workings. The new company has made an exam- ination of its property with drills, checked by shafts sunk. The values are not given. In depth the gravel averages about 36 feet, and varies considerably in char- acter of material, there being- many large bowlders, mak- ing an open connection of buckets necessary. The bed- rock varies, some being shale, but mostly hard greenstone. GOLD DREDGING IN CALIFORNIA, 107 Electric power generated by water power belonging to the company is used. The amount consumed in the dredge is 100 horse-power, which costs $2 per horse-power per month. There is an abundance of cheap water in all this country. Wages are $3 for winchmen, and $2.25 and $2.50 for ordinary laborers. Transportation is by rail from San Francisco, 337 miles, and by team over reasonably good roads, 25 miles from Gazelle. Scott Valley furnishes food supplies at low rates. The gold is coarse and worth from $17 to $18 per ounce. No platinum is found. ILL. No. &l. CONSOLIDATED MINING AND DREDGING COMPANY'S DREDGE AND CAIS- SON—THE CAISSON SHOWS AT STERN OF DREDGE. SISKIYOU COUNTY. The company proposes to have the dredge dig its own channel down the river over a mile to where the bedrock is softer. The dredge is of the Risdon type, with 5 cu. ft. bucket capacity, and the owners are at present making some modifications, particularly as to the bucket line, on account of the hardness of bedrock. The buckets are to be made much stronger, with lips heavier than is usual. These are 8 inches wide, and weigh about 140 pounds, against the usual 90 pounds, and protrude about 2 inches beyond the bucket. The links on which the buckets are placed are 6i4 inches deep and are connected by 234-inch pins. These links are 26 inches between center pins. The sides of the tumbler are 211/2 inches. U)S IHM.P 1>KK1H!IN^; IN C \1 1 KOU N I A. Y rtkii Citd,- Hold />/■((/ X.. K, 7 \V. Ai^\i o( lu>Uliuii>i, -00 ;u'ros. Oporalioiis wimh' i'omnuMU'(\l u\ IS!'!', with ;i siuizlo dippor ilroilui". Init oiilsulo of [he A\p\^cr. \\w msialhition to luiuillo lt\o i^T.-ivol I'onsists ot' two iilontu'al plants, one on oat'h sulo o\' \\\c Avcdixc. Spuils aro usoil for holduii:- fho Invit ni pla^'o, 'Vhc liippor. of 1 oubio yard i.'apa<.'Uy. iluuips on a rt^volvniu' s^'roon IS foot lon^-. with l-nioh Itolos in tlio tit-st U^ foot and > •_- moh holos in tho routainiiii:- S foot. Tho sluioiui;" tablos afo pfovidi\l with burlap and w iro-niosh i-itllos. toiivthor witli sUnoo boxos. '^0 mohos w ido. with Uunu-afian riitlos. A Iniokot staokoi- is nsod It is olaiiuod that iindor fav(M-ablo oonditions tho drodiTO oan handU> \.\00 oubii* yards daily, ('•wini: lo hard bodrook. tliofo woiv oontinnal bvoakdow ns and tho drodi^o i^ now idU\ ^See III. No. ti;>.^ Klamath Eher Gold Mimvp C(>mpa in/. rL A. Fostor. prosidont. Biuu-s. In Sw. 22. T. 46 "N.. H. T \V.. on tlie KUamath Kivor. .\roa of holdmirs. 77 aeivis. This oompany boizan oporations in -Inno. UHU. witli a dtvdiro dosijrnod by Mr. l-'ronoli. It is a steam-shovol droo.iio. but tho buoket d<.vs not work on a boom, it boiuii' lUiU'od by two stool oablos. This company's pivpovty is on (..arvoy's Ivir. on il\o Klamath Kivor. a littlo rtboYo the month of llumlnii:' Orook. The avora^o dopth of Uio iiravol is tiO feet, lyin^ on a medium hard slate. It is eotuise and there aro niaiix' lai"ge bo\YUiei*s. It is a blue iiravel. with snlphnivts. but withou! blaek sand. Tlie ^^Id is UK>stlY tine, and worth about !^17,80 per oiinoo. Waires ai-e $4 for the engineer, and $2 for labonM*s. Steam powor ovists 5^o per hoi'st^-power per month. .\t pn>sent the di*eil^^ is uot boiuiT operated. -1. (\ Brokaw, Fort doues, is operating an hydraulie elevator in Quartx Valley. It is of the Henti\- type, of 2t^ inehes diameter, with 6-ineh noxjile. ^Yith 1.5(.K> inehes of water under 230 feet of pressure. the owner ivports that 2,5W enbie yanls of jriiwel is raised 30 feet in twenty- four houi"s. APPENDIX. CALIFORNIA STATE MINING BUREAU. This institution aims to be the chief source of reliable information about the mineral resources and mining industries of California. It is encouraged in its work by the fact that its publications have been in such demand that large editions are soon exliausted. In fact, copies of them now command high prices in the market. The publications, as soon as issued, find their way to the scientific, public, and private libraries of all countries. STATE MINERALOGIST. The California State ]\Iining Bureau is under the supervision of Hon. Lewis E. Aubury, State ^Mineralogist. It is supported by legislative appropriations, and in some degree performs work similar to that of the geological surveys of other States ; but its purpasas and functions are mainly practical, the scientific work being clearly subordinate to the economic phases of the mineral field, as shown by the organic law governing the Bureau, which is as follows : Sec. 4. It shall be the duty of said State Mineralogist to make, facilitate, and encourage special studies of the mineral resources and mineral industries of the State. It shall be his duty : To collect statistics concerning the occurrence of the economically important minerals and the methods pursued in making their valu- able constituents available for commercial use : to make a collection of typical geological and mineralogical specimens, especially those of economic or commercial importance, such collection constituting the Museum of the State Mining Bureau ; to provide a library of books, reports, drawings, bearing upon the mineral industries, the sciences of mineralogy and geology and the arts of mining and metallurgy, such library constituting the Library of the State Mining Bureau ; to make a collection of models, drawings, and descriptions of the mechanical appliances used in mining and metallurgical processes : to preserve and so maintain such collections and library as to make them available for reference and examination, and open to public inspec- tion at reasonable hours ; to maintain, in effect, a bureau of information concern- ing the mineral industries of this State, to consist of such collections and library, and to arrange, classify, catalogue, and index the data therein contained, in a manner to make the information available to those desiring it, and to provide a custodian specially qualified to promote this purpose ; to make a biennial report to the Board of Trustees of the Mining Bureau, setting forth the important results of his work, and to issue from time to time such bulletins as he may deem advisable concerning the statistics and technology of the mineral industries of this State. THE BULLETINS. The field covered by the books issued under this title is shown in the list of publications. Each bulletin deals with only one phase of mining. ]\Iany of them are elaborately illustrated with engravings and maps. Only a nominal price is asked, in order that those who need them most may obtain a copy. 112 CAIJPORNIA STATE MINING BUREAU. THE REGISTERS OF MINES. The Registers of Mines form practically both a State and a County directory of the mines qf California, each county being represented in a separate pamphlet. Those who wish to learn the essential facts about any particular mine are referred to them. The facts and figures are given in tabular form, and are accompanied by a topographical map of the county on a large scale, showing location of each mineral deposit, towns, railroads, roads, power lines, ditches, etc. HOME OF THE BUREAU. The Mining Bureau occupies the north half of the third floor of the Ferry Building, in San Francisco. All visitors and residents are invited to inspect the Museum, Library, and other rooms of the Bureau and gain a personal knowledge of its operations. THE MUSEUM. The Museum now contains over 16,000 specimens, carefully labeled and attractively arranged in showcases in a great, well-lighted hall, where they can be easily studied. The collection of ores from Cali- fornia mines is of course very extensive, and is supplemented by many cases of characteristic ores from the principal mining districts of the world. The educational value of the exhibit is constantly increased by substituting the best specimens obtainable for those of less value. These mineral collections are not only interesting, beautiful, and in every way attractive to the sightseers of all classes, but are also educa- tional. They show to manufacturers, miners, capitalists, and others the character and quality of the economic minerals of the State, and where they are found. Plans have been formulated to extend the usefulness of the exhibit by special collections, such as one showing the chemical composition of minerals; another showing the mineralogical composition of the sedimentary, metamorphic, and igneous rocks of the State; the petroleum-bearing formations, ore bodies, and their country rocks, etc. Besides the mineral specimens, there are many models, maps, photo- graphs, and diagrams illustrating the modern practice of mining, milling, and concentrating, and the technology of the mineral indus- tries. An educational series of specimens for high schools has been inaugurated, and new plans are being formulated that will make the ]\Iuseum even more useful in the future than in the past. Its popu- larity is shown by the fact that over 100,000 visitors registered last year, while many failed to leave any record of their visit. 8— GD 114 CALIFORNIA STATE MINING BUREAU. THE LIBRARY. This is the mining reference library of the State, constantly con- sulted by mining men, and contains between 4000 and 5000 volumes of selected works, in addition to the numerous publications of the Bureau itself. On its shelves will be found reports on geology, min- eralogy, mining, etc., published by states, governments, and indi- viduals ; the reports of scientific societies at home and abroad ; encyclopaedias, scientific papers, and magazines; mining publications; and the current literature of mining ever needed in a reference library. Manufacturers' catalogues of mining and milling machinery hy California firms are kept on file. The Registers of Mines form an up-to-date directory for investor and manufacturer. The librarian's desk is the general bureau of information, where visitors from all parts of the world are ever seeking information about all parts of California. READING-ROOM. This is a part of the Library Department and is supplied with over one hundred current publications. Visitors will find here various California papers and leading mining journals from all over the world. The Library and Reading-Rpom are open to the public from 9 a. m. to 5 p. M. daily, except Sundays and holidays. THE LABORATORY. This department identifies for the prospector the minerals he finds, and tells him the nature of the wall rocks or dikes he may eiLcounter in his workings; but this department does not do assaying nor compete with private assayers. The prasence of minerals is determined, but not the percentage present. No charges for this service are made to any resident of the State. Many of the inquiries made of this depart- ment have brought capital to the development of new districts. Many technical questions have been asked and answered as to the best chemical and mechanical processes of handling ores and raAv material. The laboratory is well equipped. THE DRAUGHTING-ROOM. In this room are prepared scores of maps, from the small ones filling only a part of a page, to the largest County and State maps; and the numerous illustrations, other than photographs, that are constantly being required for the Bulletins and Registers of Mines. In this room, also, will be found a very complete collection of maps of all kinds relating to the industries of the State, and one of the important duties of the department is to make such additions and corrections as will keep the maps up to date. The seeker after information inquires here if he wishes to know about the geology or topography of any district ; about the locations of the ncAV camps, or positions of old or abandoned 116 CATJFORXIA STATE MINING BUREAU. ones; about railrdnds, stauo I'oads, and trails; or about the woi-king drawing's of anylliinu' conncctod with mining. MINERAL STATISTICS. One of the features of this institution is its mineral statistics. Theii- annual compilation by the State Mining Bureau began in 1893. No other State in the Union attempts so elaborate a record, expends so much hibor and money on its compilation, or .secures so accurate a one. The State Mining Bureau keeps a careful, up-to-date, and reliable but confidential i-egister of every producing mine, mine-owner, and mineral industry in the State. From them are secured, under pledge of secrecy, reports of output, etc., and all other available sources of information are used in checking, verifying, and supplementing the information so gained. This information is published in an annual tabulated, statistical, single-sheet bulletin, showing the mineral pro- duction by both substances and counties. TOTAL GOLD PRODUCT OF CALIFORNIA-1848-1903. 1848... 1849 . 1850... 1851... 1852- . :|;'245.S(i 81,294,701) 185.3 67,613,487 1854 69,433,931 1855 55,485,395 1856 57,509,411 1857. 1858. 1859. 1860- 1861. 1862. 43,628,172 46,591.140 4."'>,s4(;..">'.i!) 44, (lit:.. It;:; 41,884,995 38,854,668 $2H,5()i,7;v; 18,265,452 17,555,867 18,229,044 17,458,1.33 1871 17,477,885 1872 15,482,194 1873 15,019,210 1874 17,2tU,s;;t; 1875 16,K7<;,n(i:i 1876. 15,(ilO,723 1877. ... 16,501,268 1867. 1868- 1869. 1870. 1882.. 1883. 1884- 1885- 1886. . 1887. ISS.S.. issi). IS'.MI.. 1891. 1892- 17,146,41(i 24,316,873 13,(!()0,0(l0 12, (it; I, (144 i4,7i(;,.'i(it; i;i,:>ss.(;i4 ILL'lLV'lH I2,:;(i!i,793 12,728,869 12,571,900 lWt3. 1S!)4. 1S97 189S IS99. 19(1(1 $12,422,811 13,923,2SI 15,.334,317 17,181,-562 15,871,4(11 15,9(Ni,47S i5,3:-!6,(i;;i 15,8(i3,:5.'i.") 16,9S9,(144 16,910,320 16,471,264 il--!t!l,.395,746,672 COUNTY RANK IN GOLD PRODUCT IN 1903. "While gold is still the leading mining product, its yield no longer puts the greatest gold-producing county in the first place. The petro- leum of Kern County and the copper of Shasta give them precedence. Gold is more widely distributed than any other substance thus far mined in California ; 34 counties out of the 57 in the State showing a gold yield in 1903, and it is known to exist in several others. The order in rank of the counties of the State, in the production of gold alone, is at present as follows : 1. Nevada.. .. ...$2,4.58,047 13. Plumas $424,112 25. Fresno $21,5.38 2 Calaveras... ... 1,904,125 14. S. Bernardino .381.197 26. Eiverside 13,4.53 3. Tuolumne . . ... 1,732,.572 15. Sacramento .. .•!:ri.646 Tulare-- 9,215 4. Amador ... 1,609,744 16. Mono . :;.';i.7i:; •^s. Monterev s,92o 5. Butte -. 1,. 571, 507 17. Sierra :;|ii.77() :':i. Los Angeles... 8,674 6. Kern . .. 1.022,3.53 18. El Dorado .-. 277,304 ;-;(i. Del Norte 7,1S3 7 Shasta ... 771,242 19. Yuba 125,830 31. Alpine 2,701 8. Siskiyou ... ... t!13,57ti 20. Madera 93,070 32. San Luis Obispo 1,840 9. Trinitv -. - 607, 72X 21. Lassen . 91,102 33. Ventura . . 1,087 10. Placer . ... .. 570,571 00 Invo 66,045 34. Orange ..... , 1,50 11. Mariposa . ,542,3,V) 23. Stanislaus .. - .52,869 12. San Diego . ... 461,516 24. Humboldt .- 38,.509 Total .$16,471,264 118 CALIFORNIA STATE MINIXG BUREAU. TOTAL MINERAL PRODUCT OF CALIFORNIA FOR 1903. The following table shows the yield and value of mineral substances of California for 1903, as per returns received at the State Mining Bureau, San Francisco, in answer to inquiries sent to producers : Quantity. Value. Asphalt - 41,670tons $503,659 Bituminous Rock 21,944 " 63,106 Borax (Crude) 34,430 " 661,400 Cement 640,868 bbls. 968,727 Chrome. 150 tons 2,250 Chrysoprase .. 500 Clays: For Pottery... 90,972 tons 99,907 For Brick 214,403 M 1,999,546 Coal 93,026tons 265,383 Copper ._.,lit,113,S611bs. 2,520,997 Fuller's Earth.. 250 tons 4,750 GlassSand . 7,725 " 7,525 Gold 16,471,264 Granite 408,625 cu. ft. 678,670 Gypsum 6,914 tons 46,441 Infusorial Earth 2,703 " 16,015 Lead... 110,000 lbs. 3,960 Lime- . ___- 496,587 bbls. 418,280 Limestone 125,919 tons 163,988 Lithia Mica 700 " 27,300 Macadam ... 6t)5,185 " 436,172 Manganese 1 " 25 Magnesite 1,361 " 20,515 Marble.. 84,624 cit. ft. 97,354 Mica oOtons 3,800 Mineral Paint 2,370 " 3,720 Mineral Water _... 1,978,340 gals. 558,201 Natural Gas 120,134 M cu. ft. 75,237 Paving Blocks..- 4,854 M 134,642 Petroleum 24,340,839 bbls. 7,313,271 Platinum. .... 1,052 Pyrites. 24,311 tons 94,000 Quartz Crystals 1,968 Quicksilver 32,094 flasks 1,335,954 Rubble 1,610,440 tons 1,237,419 Salt. .- -- 102,895 " 211,365 Sandstone 353,002 cu. ft. 585,309 Serpentine 99" " 800 Silver - 517,444 Slate - 10,000 squares 70,000 Soapstone .. . 219 tons 10,124 Soda 18,000 " 27,000 Tourmaline. 100,000 Turquoise .. .- - . 10,000 Total value |.37,759,040 CALIFORNIA STATE MININ(; BUREAl^ 119 RELATIVE RANK OF COUNTIES IN TOTAL MINERAL PRODUCT IN 1903. 1. Kern $4,957,602 2. Shasta 8,201,680 3. Los Angeles... 2,54H,12S 4. Nevada 2,4»;(>.(i44 6. Calaveras 2,27u,6t).s 6. Tuolumne l,7i»l,(i."i(i 7. Amador 1,639,819 8. Butte 1,581,325 9. San Bernardino 1,516,618 10. Orange 1,029,435 11. Napa 896,848 12. Fresno 848,628 13. San Francisco. 802,786 14. Placer.. 8(M),985 15. Ventura 714,766 16. Santa Clara.. . 670,159 17. Siskivou 663,598 18. San Diego 663,315 19. Trinity 621,244 Mariposa Alameda Sacramento .-. ^ladera Riverside Plumas .-- Colusa Solano ... Santa Barbara - San Benito. . . Mono . Sierra Lake El Dorado S'n Luis Obispo Santa Cruz San Mateo Marin Sonoma . 1552,516 i 530,207 50(5,796 489,525 446,449 424,894 420,468 404,614 384,688 367,851 360,024 311,246 2i»4,018 284,304 j 257,416 254,247 i 252,500 218,427 1 195,369 I Invo 11.39,563 Yuba 125,871 Lassen 92,305 Stanislaus ... 70,605 Contra Costa. 62,500 Monterey. 51,436 Humboldt ... 49,31(i San Joaquin _ 44,4X9 Tulare .. ... 41,175 Kings ._ ... 24,200 iSlendocino .__ 20,580 Del Norte 7,183 Tehama 7,000 Alpine 2,847 Yolo 144 Merced 780 Unapportioned 377,783 Total 137,759,040 MINING BUREAU PUBLICATIONS. Publications of this Bureau will be sent on receipt of the requisite amount and postage. Only stamps, coin or money orders will be accepted in payment. {All puhlications not mentioned are exhausted.) Attention is respectfully called to that portion of Section 8, amend- ment to the IMining Bureau Act, approved ]\Iarch 10, 1903, which states : "The Board (Board of Trustees) is hereby empowered to fix a price upon, and to dispose of to the public, at such price, any and all pub- lications of the Bureau, including reports, bulletins, maps, registers, etc. The sum derived from such disposition must be accounted for and used as a revolving printing and publishing fund for other reports, bulletins, maps, registers, etc. The prices fixed must approximate the actual cost of printing and issuing the respective reports, bulletins, map.s, registers, etc., without reference to the cost of obtaining and preparing the information embraced therein." Prioe. Postage. Report XI— 1892, First Biennial $100 .$0 15 Report XIII— 1896, Third Biennial 100 20 Bulletin No. 5 — "Cyanide Process" (4tli edition), bound 60 08 Bulletin No. 6— "Gold Mill Practices in California" (3d edition) .50 04 Bulletin No. 9 — "Mine Drainage, Pumps, etc.," bound 60 08 Bulletin No. 15— "Map of Oil City Oil Fields, Fresno County, Cal." 05 02 Bulletin No. 16 — "Genesis of Petroleum and Asphaltum in California," (3d edition) - 30 03 Bulletin No. 18 — "Mother Lode Region in California" 35 06 Bulletin No. 23— "Copper Resources of California" 50 * 12 Bulletin No. 24— "Saline Deposits of California" .50 10 Bulletin No. 27— "Quicksilver Resources of California" 75 08 Bulletin No. 30 — "Bibliography Relating to the Geology, Palaeontology and Mineral Resources of California, including List of Maps" .50 10 Bulletin No. 31— "Chemical Analyses of California Petroleum" ... 02 Bulletin No. 32— "Production and Use of California Petroleum" 75 08 Bulletin No. 33— "Mineral Production of California— 1903" __. 02 120 CALIFORNIA STATE MINING BUREAU. Price. Postage. Bulletin No. 34— "Mineral Production of California for 17 Years" |0 02 Bulletin No. 35— "Mines and Minerals of California" _.. 04 Map of Mother Lode !fO 05 02 Gold Production in California from 1848 to 1904__ _,. 02 Register of Mines, with Map, Plumas County 25 08 Register of Mines, with Map, Siskiyou County 25 08 Register of Mines, with Map, Trinity County ... 25 08 Register of Mines, with Map, Lake County 25 08 Register of Mines, with Map, Nevada County 25 08 Register of Mines, with Map, Placer County... 25 08 Register of Mines, with Map, El Dorado County 25 08 Register of Mines, with Map, Inyo County 25 08 Register of Mines, with Map, Shasta County 25 08 Register of Mines, with Map, San Bernardino County. 25 08 Register of Mines, with Map, San Diego County 25 08 Register of Mines, with Map, Sierra County 25 08 Register of Mines, with Map, Amador County. 25 08 Register of Mines, with Map, Tuolumne County 25 08 Register of Mines, with Map, ButteCounty.. 25 08 Register of Mines, with Map, Mariposa County 25 08 Register of Mines, with Map, Kern County 25 08 Register of Oil Wells, with Map, Los Angeles City 35 02 Relief and Mineral Map of California 25 05 Map of Calaveras County 25 08 In Preparation : Gems and Jewelers' Materials of California . . Structural and industrial ^Materials of California ... Samples of any mineral found in the State may be sent to the Bureau for identification, and the same will be classified free of charge. It must be understood, however, that no assays, or quantitative deter- minations, ivill he 7nade. Samples should be in lump form if possible, and the outside of package should be marked plainly with name of • sender, postoffice address, etc., and a stamp should be inclosed for reply. l.L,sraH>^i IHRH 'IK DREDGE LOCATIONS /V9 1. dredge: of folsom dev. co 4. TOWN OF dredge" FD£U CO. 5. F DEV. CO. (/3^ hucMefdredse) 6. SYNDIC/^TE DREDGE CO. 7. S/ilLOR B/iR'/)SHBURTON D. CO a. F DEI/ CO (/jft buo/fef driLdga) 9. EL DOR/iOO GOLD D CO ILL. No, Oil. FIELD OF OPERATIONS IN FOLSOM DISTRICT, SHOWING LOCATIONS OF DREDGING COMPANI pAcr c^oaanci ooo.oj^' !Q§*'. .'ilui 1 {■ .a .Xt!! .1 .c,i: .it .'■:• DREDQE DATA ACCOMPANYINQ BULLETIN No. 36=-= Issued by the State Mining Bureau, Ferry Building, San Francisco. LEWIS E. AUl o. 36==-" DREDGE MINING LEWIS E. AUBURY, State Mineralogist, 1905. IN CALIEORNIA." Revolving. Revolving. Revolving. Revolving. Shaking. Shaking. Revolving. Shaking. Revolving. Shaking. Revolving. Revolving. Shaking. Shaking. Shaking. Shaking. Shaking. Revolving. Qold-Saving Tables. Cocoa matting and expanded metal. Cocoa matting and expanded metal. Cocoa matting and expanded metal. Cocoa matting and expanded metal. Riffles. } Bucket. ( Bucket. i Bucket. Belt. Riffles. Cocoa matting expanded me Riffles. Revolving. | Revolving, j Shaking. Revolving. Revolving. Shaking. Shaking. Shaking. Revolving. Revolving. Revolving. I Bucket. Electric. Hectric. Electric. Electric. ( Bucket. expanded metal. expanded metal. Cocoa matting and expanded metal. Riffles. I Belt. Cocoa matting and It „„„,,„, expanded mital. } Bucket. Cocoa matting and I n„„i,„* expanded mStal. 1} Bucket. - I Belt. Cocoa matting and expanded metal. Belt. Riffles. Cocoa matting and expanded metal. Riffles. Cocoa matting and expanded metal. Electric. Electric, tlcctric. Electric. Electric. Electric. Electric. Electric. Electric. Electric. Electric. Electric. Electric. Electric. Electric. - ) cperK.VV. ( 75,000 50,000 36,000 50,000 90,000 60,000 60,000 I 35,000 60,000 ( 80,000 120,000 90,000 30,000 65,000 Shafts and drill. Drill Drill Drill Drill DrUl... Drill .. Shafts . Drill... The first successful dredge in ( , KA 1 Cost Of equipment includes in 1 pump station. ! 50 •Oolden Slate and Miners' I ron I There were no breakdowns, no repair cost I dredge. Exceptional case. I 'Lmk Belt Machinery Co., builders. Pew h f sampling. , -Cost of power for 12 months, |8.3m.0O. •per hour fZ Shafts und pipes j| treason r«biiiliHng dredge. One-inch holes in screen. May. instead o dredge, use hydraulic elevator. Uata from old dredge, now dismantled. Nc (Monarch) building. Remodeling dredge, owing to conditions dilTerent Many sulplmrets but no Formerly Souther dredg Evans hydraulic elevatt One Martin hydrauli hydraulic elevator. IV 1/1 .nijiaiBH .L .' axhaBH .1 ;;i:v//ll9UaoS: .H .H •i1 .niwboof) .7/ .(. ' iiflB ..aeif ,ii'r//boor) .'(I . ■■('■"<-i() ,.^gM,7Tl■•"■• allivoiO ,.T§M ,noiM .nofmnaH ."I . ' ili/oiO ..T^M ,o^nuVi .H .C) i.f/uiO ,,i^l(C .q■iau^...ll ''» .toHjafa 8(iiv I»^r:^f>^^(J blogligM oO sniaiM bfiB j^nijih-jitl bl<. ...<>'> ynhifM •■lIivti^-iUbiU2 tiulist^i.- ''J gaisbeiQ aiinoiilsO boh doJeoll . .o') yniybsid BirnoiiljjiJ him ii6Iet>9 •oO noilBiolqxa b(ia gni^b^iid bloO sllivdiO ..•• (...Mf-,.>t.,v:^ biiu T^oiabaxfl blo-DaHivfitO .o!J j(iii3b9iG bioO deiJon ^/'' ' '/> ^m»ibeia Wof>.»*ioa , . . -I .? > sniabiia oidq la, !f9^:He;i .11 .«Bl . abJ-H"? bloO b9l«biIoii^U adii >■: fi)ii Ac-; Ml ^^^■■^ Wi