USA > Colorado > History of Nevada, Colorado, and Wyoming, 1540-1888 > Part 13
USA > Nevada > History of Nevada, Colorado, and Wyoming, 1540-1888 > Part 13
USA > Wyoming > History of Nevada, Colorado, and Wyoming, 1540-1888 > Part 13
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37 S. F. Alta, Aug. 7, 1863. There was but a few minutes difference in the time of starting up. C. W. Coover was associated with Harris. Their mill was built on the east side of the road, nearly opposite the present Levi- athan hoisting works, the site being one formerly located by Overman for arrastras. The mill consisted of one of Howland's 9-stamp portable rotary batteries, the engine and boilers being from Goss & Lambert's, Sacramento, and hauled over the mountains by ox-teams, at 4 and 5 eents a pound, taking 18 days to the passage. On the 13th of August this mill began on eustom- work, running continually on ore from the Bowers and Gould and Curry elaims until October, when it was stopped to make the change from the dry to the wet process. Paul's first mill was ereeted at Devil's Gate, 5 miles from Virginia City, and if we are to believe the S. F. Bulletin of Aug. 15th, was in operation before Harris'. He built another, the 3d in the territory, consisting of 8 Howland batteries (72 stamps), below lower Gold Hill. The 4th mill was by the Ophir company; and the 5th by Staples at Gold Hill; the 6th by W. S. Hobart at Gold Hill; the 7th by the Nevada company, in Six- mile eañon. Wood being required to run steam-mills, what there was in the vicinity brought a continually inereasing priee from $4.50 to $15 per eord.
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THE COMSTOCK LODE.
$14 an ounce, and even at this low rate the Comstock mines yielded $1,800 and $2,000 per ton in gold.
As soon as it was settled in the public mind that the mines in Virginia and Gold Hill districts were upon the same lead, it became of importance to know the extent and dip of the great vein. There was, as might have been expected, a conflict of opinion. Some placed their faith upon the Flowery district, east of Virginia City about five miles. In this district were the Rodgers, Morning Star, Mammoth, Desert, Nary Red, Lady Bryan, Marco Polo, and Cedar companies. It was asserted with much confidence that this dis- trict excelled the Virginia district. The mines of the Devil's Gate district, south of Gold Hill, were said to be the next best in the territory.
All the work done which could serve as an indica- tion of the actual value of the mines was being done in two or three mines of the Virginia district, namely, the Ophir, Mexican, and Californian. The Mexican was being worked after the method pursued in the mines of Mexico. A shaft was sunk, about fourteen by eight feet in size, which came to the vein ten or fifteen feet from the surface. From this point the inclination of the vein was sufficient to allow of rude steps being cut on the lower side of the shaft, up which clambered the Mexican miners, carrying on their backs, suspended by straps round their foreheads, ox-hide baskets filled with ore. In this primitive way, with little expense, they brought up from the bottom of the shaft a richly paying quantity of ore. Forty or fifty feet below the surface drifts were run, and from the drifts other shafts were lowered. This system left standing pillars of ore, which supported the mine, and obviated the necessity for expensive timbering. A tunnel was, however, run in at a depth of eighty feet, and when the miners had reached that depth, and a greater depth, the tunnel was utilized for a roadway to bring out the ore in loaded cars, an approach to American methods of mining.
113
MILLS AND MACHINERY.
The Ophir company employed steam hoisting and pumping machinery in 1860, driven by a fifteen horse- power donkey-engine. It was worked by an inclined shaft following the dip of the vein, up which the ore- car was hoisted. In December 1860 the Ophir com- pany had reached a depth of 180 feet, using the post and cap supports common in California mines, and found the ore body to be of the unexampled breadth of forty-five feet. They had not followed the Mexi- can plan of leaving pillars of the rock to support the weight of the superincumbent earth. Timbers of suf- ficient length and strength to prevent the sinking in of the roof of the mine over so wide a space, could not be obtained, even if they would have had the required imperishability to make them safe. 38 This difficulty, encountered in the heart of the bonanza, became of the most serious import, and the company sought the aid of the engineering genius of Philip Deidesheimer, a German miner of scientific attainments
Deidesheimer was equal to the occasion, inventing in three weeks of study and observation a system of timbering without which the Comstock mines would have remained sealed below a certain depth. The plan was simply that of timbers framed together in square sets, forming cribs of from four by six feet in size, which could be piled one upon the other to any required height, and which could be made to conform to any circumstances of lateral as well as downward pressure. These cribs, filled with waste rock, could be made enduring pillars reaching to the roof of the deepest mine. Here at once, in the beginning of its
38 On the morning of the 15th of July, 1863, half of the Mexican mine, from the surface to a depth of 225 feet, caved in. It carried the ponderous mass of rock, earth, and timbers over into the Ophir, demolishing 50 feet of the 4th gallery, and portions of the 2d and 3d galleries. The main shaft of the Mexican was closed up, and a part of the mill undermined. Not a life was lost, all the men in the mine barely escaping. Lord's Comstock Min- ing and Miners in King's Survey, 217. On the 5th of March, 1865, a great cave rent open Gold Hill, filling the upper levels of the Empire, Imperial, and Eclipse mines. Many accidents of this nature happened, and made re- course to cribbing imperative. Gold Hill News, May 31, 1869, Jan. 3, 4, June 29, 31, 1870.
HIST. NEV. 8
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THE COMSTOCK LODE.
mining history, the Comstock lode received exactly the service needed for its complete development. Nor was it the fertile American brain which achieved the triumph over an obstacle that threatened to be insur- mountable, but the sturdier German intellect.39 Other suggestions of Deidesheimer's were afterward adopted, with great profit, regarding the kind of machinery to be used.
PLAN OF CRIBBING.
39 Deidesheimer's device was particularly adapted to the extraction of the ore bodies of the Comstock, and would have obviated the difficulty encoun- tered in the early development had it been applied. Wright describes the former method as follows: 'The only supports used in the mines were round logs cut on the surrounding hills. These logs were from 16 to 35 feet in length; when of the latter length, they were manufactured, that is, were made of two logs spliced and held together by means of iron bolts and bands. Owing to the stunted character of the pines and cedars found in the neighbor- hood, it was almost impossible to procure a log more than 20 feet in length. After setting up two of these logs, a log 18 feet long was placed upon them as a cap. These posts and caps were placed as close together as they could be made to stand, but they would not hold up the ground when it began to slack and swell from exposure to the air. Besides this difficulty, there was no safe way of working either above or below these sets in the vein. To take out ore, either under or over the timbers, loosened them and caused a disas-
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TIMBERING.
The discovery of the new method was made none too soon, for at the level next below the one hundred and eighty-foot, or third gallery, the ore body had widened out to sixty-six feet. Locators not in the bonanza mines were watching with much anxiety the dip of the Comstock, hoping to secure claims on the lode where it should make its appearance beyond the limits of known locations. For a time it seemed to dip toward the west, and to run beneath Mount Davidson, on the eastern slope of which the croppings plainly appeared. Locations on the east side of the Virginia range were then eagerly sought after; but when the depth of 300 feet had been reached in the Ophir mine, the lead was found to have been bent and deflected from its true course by the pressure from above, and that its true dip was toward the east, and away from Mount Davidson. This discovery gave a new interest to the Flowery district.
Mills for crushing ore rapidly having been intro- duced, the question of entering upon silver-mining
trous eave. Many accidents happened, and many men lost their lives while this method of timbering was practised, but no lives have ever been lost in timbering by the square-set, or Deidesheimer plan. In the mines at Gold Hill was where the timbers 35 feet in length were used, and there was where the greatest number of accidents happened; but in the Ophir mine timbers 16 feet long had been used .... In 1861 the new style of timbering was adopted along the whole line of the Comstoek, and has been in use ever since. The Ophir was probably the first mine in any part of the world where such a system of timbering became a necessity, as no ore body of such great width had ever before been found.' Big Bonanza, 135. See also Lord's Con.stock Mining and Miners, one of an interesting group of monographs belonging to thr report of the U. S. geog. sur., of which Clarenee King was director, the expenses being paid and the books published by goverment.
Philip Deidesheimer was born in Germany in 1832, and came to California via Cape Horn in 185], where he remained until 1860. In Nov. of that year Mr W. F. Babcock, agent of the P. M. S. S. Co. and leading director of the Ophir mining company of Nevada, sent for Mr Deidesheimer, who was then mining in El Dorado county, to ask him to propose a plan for working the Comstoek mines, for unless some way of supporting the ground was dis- covered they conld not be worked, on account of the width of the vein, 60 feet, and the softness of the earth. In his earnestness to assist Mr Babeock Mr Deidesheimer took no thought of himself, or he would have patented hi: invention. This he did not do, and all the mines seized upon it as quickly as it became known. It would seem that some reward should voluntarily bave followed, though none did. He was made superintendent of the Op! r, and earned his salary as mining engineer the same as another, and the mine owners became rieh through his invention.
116
THE COMSTOCK LODE.
proper was the next consideration. Ophir, Mexican, and other Virginia ores of sufficient value, after assort- ing, to be sent to England for reduction had been sent, and the remainder, as second and third class ores, were allowed to accumulate. At Gold Hill they had not yet worked through the gold to the silver ore, when experimenting with the latter began at Vir- ginia. It was a difficult problem for the unlearned and inexperienced American miner and mill superin- tendent. The man of science might have found many baffling peculiarities about the silver ores of western Utah ; therefore it is not surprising that the merely practical man, without experience, encountered many discouragements. The surprise is that they so readily
conquered them.40 During the experimental period millions of dollars went to waste in the "tailings," or pulverized ore, which ran away from the mills after passing through the pans and other apparatus used in amalgamating silver by the wet process. They were swept into the Carson river through the cañons in which the mills were situated, and deposited finally in the sink of the Carson, where they lie embedded. Only the Mexicans knew the value of these tailings,
40 Says Wright, in his Bonanza, 139, 'The amalgamating pans in the mills surpassed the caldron of Macbeth's witches in the variety and villainousness of their contents. ... They poured into their pans all manner of acids; dumped in potash, borax, saltpetre, alum, and all else that could be found in the drug stores, then went to the hills and started in on the vegetable kingdom. They peeled bark off the cedar-trees, boiled it down until they had obtained a strong tea, and then poured it into the pans where it would have an oppor- tunity of attacking the silver stubbornly remaining in the rocky parts of the ore .... A genius in charge of a mill conceived the idea of making a tea of this, (sage-brush or artemesia) and putting it into his pans. Soon the wonders of the sage-brush process, as it was called, were being heralded through the land. The superintendent of every mill had his secret process of working the silver ore ... Process peddlers, with little vials of chemicals in their vest pockets, went from mill to mill to show what they could do, provided they received from $5,000 to $20,000 for their secret.' Hittell's Hand-Book of Mining, pub- lished in 1861, mentions without describing the Bagley and Veatch processes, and says that the Ophir company used the former, and the Central company the latter. The Ophir company finally paid $10,000 and a royalty for the Veatch process. The 'sulphuret puzzle' is discussed in the S. F. Herald, March 22, 1869; S. F. Times, June 23, 1867. Reduction methods continued to be discussed and changed for several years. The chlorinizing process received much attention about 1871. Gold Hill News, Sept. 3 and Oct. 28, 1871; Carson Appeal, June 18, 1869.
117
PROCESSES.
or attempted to save them, a few of them securing several thousand dollars each by the patio process, at a small expense. But afterward pieces of amalgam were frequently found in crevices of the rocks over which the tailings had flowed, large enough when melted to make rings or buttons. It was only after a long time that any systematic methods were adopted by mill-owners to save the gold and silver in tailings."
The California company, which was located next south of the Ophir, was the first to run a tunnel in upon the ore deposit, which it did in 1859-60, having to timber it, on account of the slacking of the earth.
All the other mines at first opened downward from the top simply by a well or shaft, which collected the water in the earth, and required pumping machinery long before its depth should have rendered pumping necessary. This machinery as well as the earlier mills soon had to give way to that which, if more ex- pensive, was also much more effective. Engines of fifteen horse-power were replaced by those of eighty
41 The patio process, as praetised in this small way, consisted in plaeing the tailings on an inclined table, and carefully pouring water over them with a small dipper, beginning at the top and working down. At the bottomn would be found, waslied down, some pounds of sulphuret of silver, and parti- cles of amalgam and quicksilver. This they placed in a patio, or amalga- mating yard elosely paved with granite, or sometimes having a well packed, hard clay bed, and when several hundred pounds had been saved, sulphate of eopper, salt, and quieksilver, in the proper proportions, were added to the mass, and the whole mixed together into a kind of mortar, and left in a heap to sweat and digest. This operation, several times repeated, the mass being mixed by the trampling of horses or mules, completed the amalgamation, when the silver could be washed out with a roeker. See Farayre Explor. Mineral, 15-18. There is an aeeount of the discovery of a natural amalgam of gold, silver, and quicksilver, in S. F. Call of May 4, 1865, quoted from Virginia Union, said to be worth $10,000 per ton; also in Sac. Union, May 4, 1865.
42 The wonderful divisibility of the precious metals and of quicksilver has been shown by placing a copper bowl, coated with quicksilver, where the water from the flume of a quartz mill should fall into it, and also some copper riffles, eoated in the same way, in the flame itself. Although the water had a perfectly clear appearance, at the end of 3 months, from the bowl and the rifles, $100 in amalgam was obtained. The water eame from the Carson river, and was eondneted for a considerable distance throngli a wooden flume, in which, on repairing it, was found amalgam adhering to the nail-heads, which must in the first place have received a coating of quicksilver, and all came from the tailings swept into the river. An interesting question has been raised of where goes the 734, 400 pounds of quicksilver once annually used in the Comstock mills. It disappears, and the millmen say that 'wherever quicksilver is lost, silver is lost.' See Gold Hill News, Aug. 9, 1871.
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THE COMSTOCK LODE.
horse-power, and finally by those of five hundred. The question of water, both in the mines and out, was one that has led to some mighty engineering feats. Silver-mining, as at present carried on, is an achievement of scientific and engineering skill which was not dreamed of in the period antedating the ad- mission of Nevada as a state. What it has to do with the history of the state will appear hereafter.13
43 As a contrast to the small beginnings described in a previous note, an account of the Consolidated Virginia mill is inserted in this place. This mill was planned by James G. Fair the bonanza manager. It stood 200 feet north-east of the company's main shaft and hoisting-works. The ground inclined toward the east, allowing of a convenient descent, and was terraced to accommodate the several departments. First came the battery room with ore bin, being 100 by 58 feet in size. Adjoining it on the east, and on a terrace a few feet lower, was the amalgamating-room, 120 by 92 feet. A little lower, on another terrace, was the room containing the settlers, 92 by 20 feet. North of the amalgamating room was the engine room, 92 by 58 feet. The whole of the machinery was driven by a compound condensing-engine of 600 horse-power. The main shaft from this engine was 14 inches in diameter, and weighed 15,000 pounds. A fly-wheel on this shaft, which was also a band-wheel and carried a large belt by which the batteries were driven, was IS feet in diameter, and weighed 16} tons. On the extreme end of the main driving-shaft was coupled a shaft 11 inches in diameter, which extended into the amalgamating-room and drove the pans and settlers, and all the machinery not connected with the batteries. The whole weight of the engine was fifty tons, and it stood on 450 cubic yards of masonry laid in cement, weighing 600 tons. There were 4 pairs of boilers, each of which was 54 inches in diameter, and which could be used separately or in connection with the others. A portion of the walls were of stone, and 22 feet high. To the ridge-pole of the roof was 50 feet; to the top of the 4 smoke-stacks 90 feet. In the engine room were two large steam pumps to be used in feeding boilers or in extinguishing fire. The mill consunied 42 cords of wood per day, which was brought to the mill from a side track of the Vir- ginia and Truckee railroad, on trucks holding two cords each. The truck was emptied into a chute which carried the wood into the boiler-room. On the the west, or highest side of the mill, higher than the roof, was a covered track, 278 feet in length, leading directly to the main shaft of the hoisting- works. When the loaded cars were brought up on the cages they were drawn in trains of 10 cars along the track to the chutes which led down from the roof of the mill to the ore bin below. The track, with the building which inclosed it, rested on strong trestle-work, 44 feet above the ground at the highest point. A car load of ore was fed to the batteries every 5 minutes. It fell first upon an iron screen through which the fine ore passed; that which had to be broken was dumped near the crusher, which resembled a huge lemon-squeezer, and was invented by Blake, and after being broken was distributed by chutes to the batteries or near them. There were S of these, with 10 stamps each-80 stamps weighing 800 pounds each-and either could be worked, started, and stopped independently of the rest. From the . ore-bin, machines called self-feeders, invented by James Tulloch of Cal., and operated by the motion of the stamps, dropped the ore into the batteries without the intervention of human muscle.
Here began the process of extracting the silver. The pulp which ran from the batteries was conducted to the settling-tanks in the amalgamating- room by sluices, When it was settled to the consistency of thick mortar, it
119
HOW IT WAS DONE.
was shovelled out upon a platform extending along the rows of amalgamating- pans, 2 rows, 16 pans in each, each pan 5} feet in diameter, and holding 3,000 pounds of pulp. In the bottom of the pans were east-iron plates, called dies, and revolving upon these other iron plates, called shoes. These pans were the invention of Henry Brevoort of Sonora, Cal., who improved upon the original amalgamating pan designed by Israel W. Knox of S. F. The pulp, to whiel some water was added, was again pulverized between these plates by revolving the upper upon the lower, steam being admitted to the mass, which was tightly covered, during the grinding. The steam was substituted for the sweating process, which requires days, where the steam effected the same work in hours. The idea was originated by Seiim E. Woodworth of S. F. After 2} hours of heating and grinding, 300 pounds of quicksilver were added to the contents of each pan, there being added besides a certain amount of salt and sulphate of eopper, and sometimes soda and other chemicals, when the grinding was continued for 2} hours longer. It will be perceived that this process did not differ from the patio process, except in the superior- ity of the mechanical arrangements, which were equal to the best in the world. At the end of this time the amalgamated pulp was drawn off into the settling-tanks, from which it passed through strainers of heavy canvas bags, when the earthly matter separated from the metallic, and only the silver and quicksilver were collected in the bags, where the mass remained until the superfluous quicksilver drained off. When no more passed through the can- vas strainers, the amalgam was removed to another, called the hydraulic strainer, a heavy east-iron vessel, shaped like a mortar-gun. Over the mouth of this vessel was fastened a strong iron cover, through which passed a pipe, also of iron. A water pipe was then connected, and water under pressure amounting to 150 pounds to the square ineh was turned on. By this method much more quicksilver was removed than by any other, but there was still mnuch left. An iron car, which ran on a track in front of the strainers, now received the amalgam and carried it to the retort house, removed from the mill a short distance. This was a brick building 24 by 60 feet, containing 6 cast-iron cylinder retorts, with a capacity of 5 tons of amalgam per day, though retorting usually only half that amount. The amalgam when placed in the retorts, had a dull, gray, muddy appearance, showing neither silver nor quieksilver. By the gradual application of intense heat the latter, which really constituted & of the whole, was finally separated from the silver. The next process was that of assaying. The assay office of the Consolidated Vir- ginia, a large, fine building near the main hoisting-works, had in the melting- room 6 furnaces, with melting-pots made of graphite, having a capacity of 300 pounds of silver each, but seldom containg much over 200 pounds. Here the silver was melted, the dross being skimmed off after stirring. When sufficiently cleared of impurities, it was poured into iron moulds, which formed bars weighing something over 100 pounds. A small ladleful of the molten metal, taken from the top and bottom of the melting-pot, was thrown into water, where it assumed various shapes, some beautiful in form, as flowers and leaves. An assay was made of these first and last granulations, which had to agree, or the melting be done over. The assay was performed by wrap- ping a gramme of the silver in a thin sheet of pure lead, placing the package in a cupel made of bone ashes, and subjecting it to the heat of a furnace. When liquefied, the lead and all other base metals were absorbed by the eupel, leaving a button of fine metal. This bit of bullion was then hammered into a thin sheet, placed in a flask of annealed glass, and strong nitrie aeid poured upon it. The flask was placed in hot sand bath-an inch or more of sand on the bottom of a very hot oven-and the sheet of bullion was boiled until the silver was all dissolved, and the gold in the form of a powder settled to the bottom of the flask. This precipitation was placed in a erucible of nnglazed porcelain, dried, and melted in a furnace, when the particles nnited, after which it was earefully weighed. The loss of weight sustained by the origi- nal button represented the silver which it had contained. The bars of bul- lion being weighed, and their relative proportion of gold and silver ascer-
120
THE COMSTOCK LODE.
tained from the assay of one gramme, their value was marked on them in degrees of fineness. The calculations were assisted by tables of values. When silver, for instance, is 900 fine, it is worth $1.16-36, per ounce; when gold is 900 fine, it is worth $18.60}. Assay of ore was similar; 200 grains, finely powdered, were melted in a crucible with proper flux, and the metal deposited was subjected to the process just described, from which the value per ton was calculated. Many ingenious contrivances for saving quicksilver were in operation at this mine, which, although interesting, were not a part of silver production, which is here briefly described, as practised after fifteen years of progress. The cost of the reduction works at, the Consolidated Virginia mine was $350,000. Other mines may have had less expensive works, but the methods pursued were the same in all. An interesting chap- ter might be written on the improvements in hoisting, pumping, and other machinery, full descriptions of which, with diagrams, are contained in Clar- ence King's report on Mining Industry, an elegant quarto, filled with instruc- tive and entertaining matter concerning the Comstock mines, from their discovery down to 1870,
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