panies on the Bobtail are shut down, Among the really successful mines are the California and U. P. R., which are, and have been, yielding their owners large profits. As they are private and personal enterprises it is exceedingly difficult to get any figures for publication. The celebrated Coaley lode is probably not surpassed in Colorado as a paying silver mine. Its total yield this season has been about $66,000. Of this amount $16,000 were realized from forty tons of ore, at an average of $400 per ton. The average price for crushing ore is $30 per cord. The supply of ore during the past summer has been about equal to the demands of the mills, and is probably now in excess. The shutting down of so many of the Nevada mills necessitates the hauling of a good deal of ore from lodes in that vicinity to Black Hawk for crushing. This is attended with an expense which cuts down the profits to a very small percentage. The late operations at the Briggs mill ought to be mentioned here, as they throw much light on the relative merits of heavy stamps with slow motion and light ones run at high speed. They had been taking out their old stamps and are putting in new ones. Twentyfive were in operation, and twenty-five more were expected to run in a few weeks. The mill formerly contained 50 stamps, weighing 650 pounds, and dropping 22 times per minute. With this mill they crushed 36 cords, or 252 tous, per week. The 25 new stamps, weighing 550 pounds each and dropping 40 times per minute, are doing the same work as by the old 50, and with all the 50 new ones in operation the capacity of the mill will doubtless be doubled. CHAPTER LIII. CLEAR CREEK COUNTY AND THE SILVER MINES. The first mines in this county were discovered as early as 1859, and both gulch and lode mining were quite brisk at Idaho City, Mill City, and Empire. All the lodes found during that time were gold-bearing, and some of the Idaho and Empire gold lodes are worked at present to good advantage. Near Georgetown several lodes were discovered at the same time; and though every one has since turned out to be a silver-bearing vein, all were first worked for gold. A small stamp mill was erected in 1863: and, according to trustworthy statements, sluicing on the Griffith lode paid well. In sinking down on these lodes, the amount of gold in the ore rapidly decreased, and at present there is hardly a trace of it left. Quite recently a lode has been found between Empire and Mill City, near the forks of Clear Creek, the surface ore of which contains five ounces of gold besides about $200 in silver per ton. Strangely enough, the ore from this lode shows very little copper or iron pyrites, while, as far as my knowledge goes, all the other lodes carried a good deal of one or the other, or both, of these minerals. Nearly all the lodes discovered around Georgetown (called at that time Elizabethtown) during the first two or three years were bought up by eastern capitalists; several stock companies were formed, but, like too many of their predecessors in Colorado mines, they did not accom plish anything. In this, as in the other counties, large sums were paid for undeveloped property; many tons of worthless machinery were sent out; large mill-buildings were erected before the mines were able to supply them; and the whole was managed by agents, generally incompe tent and without experience in the business. Only one of these companies is at present in a healthy and thriving condition. This one confined operations exclusively to the development of what was thought to be its best property. Not having wasted money foolishly, it had the means to erect, of late, large dressing works, managed by a competent superintendent, and its operations are now in a promising condition. The first prospecting for silver ore was done in 1864 by Messrs. Steele, Huff, and Layton, from Empire, and the discovery of the Belmont lode, on McClellan Mountain, was the immediate result. Several assays made of the surface rock yielded several hundred dollars per ton; and 2.75 tons worked by Garrott, Martine & Co., in the fall of 1867, yielded $619 34 in coin. At present the company is putting up one of William Brückner's cylinders; a poor streak, however, has been met with in the mine. During the next two years there was a perfect rush to the silver mines from all the other counties, and a large number of good lodes were discovered on nearly every hill around Georgetown. Several smelting concerns were erected during that time, none of which, however, were able to beneficiate the ore to advantage. In 1867, the active development of some of the prominent lodes was commenced, and work has been carried on since that time, at the Equator, Terrible, Baker, Brown, Coin, Clift, Griffith, and some others of less importance. The work being, however, at most exclusively confined to sinking shafts and driving tunnels, the whole amount of ore mined, up to April 1, 1869, does not exceed 1,100 tons, which, at the lowest estimate, yielded $250,000 in coin. At present some of the lodes are in tolerably good shape for working, and very likely the amount of ore mined this year will be four or five times as large as the whole production heretofore. As to the constant call of the newspapers for more and larger reduction works, I must, however, remark, that there is no present reason for such a demand. According to my judgment it is an utter impossibility for the mines to keep even those works in full supply which are finished, or will be so in a very short time. Until June, 1869, every one of the three small mills at Georgetown lay idle frequently, and during the finest part of the season Mr. Stewart was afraid of being forced to stop for lack of ore. Leaving the large dressing-works of the Wilson & Cass Co., which claim a capacity of 60 tons per diem, entirely out of consideration, the following amount of ore is needed to keep all the reduction works in supply: Georgetown Silver Smelting Company's works.. Baker Silver Mining Company's amalgamating works.. 3 tons per day. 8 tons per day. 8 tons per day. 5 tons per day. .12 tons per day. 4 tons per day. This gives a total of 40 tons per day, or counting 300 working days, 12,000 tons a year. However strong the people's faith may be in the productiveness of the silver mines, there is not at present the least possibility of supplying half that amount. In fact, my boldest expectations will be surpassed if 5,000 tons of good ore are furnished by the mines. Whoever has seen extensive and well-developed lodes and is acquainted with the production of such, must know that only a limited number of workmen can be profitably employed in a lode, the development of which has been accomplished only to a certain degree. In order to steadily increase the ore production of a mine, it is not enough to start a couple of new stopes; the main object must always be to keep opening the ground ahead, so that there shall be always ore enough in H. Ex. Doc. 207- -24 sight to maintain a steady and continuous production. The quantity of ore extracted from a mine reasonably ought to be in direct proportion to the quantity of ore in the reserves; and as there are at this time only half a dozen lodes in and about Georgetown which might be called even partially developed, it is utterly absurd to expect 12,000 tons to be extracted the ensuing year, without endangering the continuous delivery of ores for the following years. Near the surface, almost all the Colorado silver lodes are more or less decomposed; atmospheric influences, combined with the action of the surface water, having gradually converted the sulphurets of lead, iron, and copper into oxides, sulphates, and carbonates. These being wholly or partly washed away, have left the quartz porous and more or less colored by oxide of iron or carbonate of copper. When opened to some depth, the lodes become galena-bearing, carrying at the same time a larger or smaller amount of zinc blende. Both the galena and the blende appear to increase with depth. They decidedly predominate in most of the deepest mines. The zinc blende, especially the dark brown variety, is often very rich in silver. In the Brown, Coin, and Terrible, it always forms a prominent part of those streaks in which ruby and brittle silver occur most abundantly. Several pieces from other lodes on Brown and McClellan Mountains, in which, even with a strong magnifying glass, not a particle of silver ore could be discovered, yielded nevertheless, by assay, from one-half to three and one-half per cent, of silver. Being generally so rich, of course, it must not be separated from the galena, and thus it forms in almost every good lode an addition to the lead ore, quite disagreeable, as far as reduction is concerned. Its presence is especially obnoxious during roasting. According to Plattner, the zinc blende may, during the operation, cause a loss of silver which may amount to 60 per cent., and in most cases is at least from 5 to 15 per cent. The ores produced by the mines at present may be divided into two classes, surface and galena ores. This distinction, of course, is not and cannot be expected to be an exact one; it is impossible to draw a strict line between the two classes, as there is a good deal of ore which might be equally well ranked with either. The surface ores generally contain, besides more or less zinc blende, a little decomposed galena and sulphuret of silver; and very often the zinc-blende is also decomposed. With increasing depth the amount of galena and zinc-blende gradually increases also, until at a depth not exceeding one hundred feet they decidedly predominate. In a few instances the decomposition reaches even further down; while, on the other hand, many lodes on Brown, Sherman, and McClellan Mountains showed a strong vein of solid galena and zinc blende, or zinc blende alone, at the very surface. Wherever the latter was the case, the zincblende was worth $200 per ton and upward. The amount of silver in the ores varies, of course, considerably, those consisting chiefly of fine-grained galena and black zine-blende being usually very rich, while pure, coarse-grained galena nearly always proves to contain but little silver. The average value of 633 tons of amalgamating ores, worked by Garrott, Martine & Co., and Huepeden, Wolters & Co., was $126 48 coin per ton; the smelting ores from the Terrible, Brown, Coin, and Equator will, however, very likely yield above $350 coin per ton. In order to show how far the development in the best lodes has advanced, I give a few sketches of the most prominent ones. I have, of course, selected those on which the most work has been done; and it is but right to say here, that besides these lodes, there are perhaps ten times as many more, which look quite as promising as did any of the veins described, at the same stage of development. There are, in fact, several hundred out-crops around Georgetown, which, so far as they have been opened, seem to belong to excellent lodes. T MAIN SH AIR SH. SH NO S. THE EQUATOR LODE.-Scale 100 feet to the inch. The shallow shaft is the discovery, east of which the lode strikes north 49° east, while west of the Escovery the strike is south 54° 30 west. Depth of main shaft, 206 feet; of the main level, 100 feet; distance between main shaft and air shaft, 115 feet. Depth of No. 2, 120 feet. G, G, are under-hand stopes in the bottom of the main level. The level is drawn in its original position. West of the disevery 120 feet, there is a shaft called No. 1 west, and 50 feet deep, and east of shaft No. 2 there is another shaft at a distance of about 115 feet, and 50 feet deep. Both from this and from shaft No. 2 there are short levels running westward, each 25 or 30 feet long. The level from No. 2 is 60 feet, and that in the easternmost shaft 30 feet below the surface. In this lode, as well as in all the other ones, stoping has but just been commenced; and the quantity of ore taken out was almost exclusively obtained by sinking and drilling. The Equator lode produced up to August 20, 1869, 300 tons of ore, yielding about $92,000 in currency. The hoisting is done by steam at the main shaft. A THE TERRIBLE LODE.-Scale 200 feet to the inch. Course of the lode, north 629 east. Dip vertical to a depth of 80 feet, thence to present depth 15° Borth. A, air-shaft, 78 feet; D, discovery-shaft, 50 feet. À 28 feet higher than D. The mine has produced 175 tons of ore, yielding $85,000 coin, or at the rate of $485 71 per ton. A large amount of second and third-class ore is on hand, worth, respectively, $200 and $70 per ton. A tunnel is now being driven, intended to strike the lode at a depth of 235 feet in the discovery shaft; the point of intersection is 350 feet from the mouth of the tunnel; 120 feet have been completed by the use of the Burleigh rock drill. B THE BROWN LODE.-Scale 200 feet to the inch. Course of the lode from discovery west, south 81° 45′ west; course of the lode from discovery east, north 81° 45' east. D, discovery shaft, 170 feet deep. A, tunnel which intersects the lode at right angles. B is intended for an air shaft, but is not, in fact, broken through to the surface yet. It lacks 35 feet. The lode has produced 275 tons of ore, yielding $72,000 coin, or at the rate of $261 82 per ton. Much second-class ore is on hand. The mine is worked from the tunnel A, through which the ore is taken out and conveyed from the adit-mouth to the foot of the mountain by means of cars, traveling upon a suspension wire cable, as shown below. Suspension tramway.-This ingenious arrangement is highly to be recommended where the construction of a road-bed might be too expenThis tramway of wire rope conveys the ores from the shaft, 1,600 sive. |