Gambar halaman

Carbovic acid...

0.72 1.50

90.42 9.52

Oxygen and water by difference...


The quantity of silver obtained from this lot of ore was 156 troy ounces to the gross ton of 2,240 pounds.

This analysis sheds important light on the chemical history of this remarkable metallic deposit, and will aid us in the study of the paragenesis of the derived species. It is pretty certain that all the heavy metals have existed originally as sulphides, and we inay, therefore, state the analysis thus, allowing 8.52 sulpbur to couvert the heavy metals to this state:

Metallic sulphides .
Al, .35; Mg, .25; Ča, .72; Äng; Mn, .20

40.9) 52. 60 1.52

35.02 4.95

Water, carbonic acid, and loss

This calculation assumes that the sulphides are as follows, viz:

Sphalerite, (blende).

38. 69 3.30 1.03 3. 62 5.42 0.54

52. 60

This statement excludes the presence of any other gangue than silica, and considering that the ores exist in limestone, the almosť total absence of lime in the composition of tho average mass is certainly remarkable. The amount of silica found is no ticeable, since quartz is not seen as such in this great ore-chamber, nor, so far as I could find, in other parts of the mine. The silica can have existed in chemical combination only in the most inconsiderable quantity, since the bases with which it could have combined are present to the extent of less than 14 per cent.; nor do we find in the mine any noticeable quantity of kaolin or lithomargo, resulting from the decomposition of silicates, por are there any feldspathic minerals. It is most probablo that the silica existed in a state of minute subdivision diffused in the sulphides, as I have seen it in some of the unchanged silver-ores of Lion Hill, in the Oquirrh Range.

The absence of chlorine and of phosphoric acid in the analysis corresponds well with absence of the species cerargyrite and pyromorphite, of which no trace could be found by the most careful search among the contents of the mine. The miners speak of the "chlorides," and the unscientific observers have repeated the statement that silverchloride is found in the Emma mine, but the ores indicated to me as such are chiefly antimonic ochers.*

The general (perhaps total) absence of the phosphates of load in the Wasatch and Oquirrh Mountains, so far as explored, is a striking peculiarity of the mineralogy of these ranges. On the other hand, the absence of chlorine in tho mines of the two Cottonwoods and the American Fork is in striking contrast with the constant occurrence of corargyrite (horn-silver) in the Oquirrh and also in the southern extension of the Wasatch. I have sought in vain for a trace of this species in the districts of the Wasatch just named, and the occarrence of pyromorphite is extremely doubtful.

Molybdic acid, however, exists pretty uniformly disseminated in the mines of the Wasatch in the form of iculfenite. Althongh it occurs in minuto quantity, it is rarely absent, and may be regarded as a mineralogical characteristic of the districts of the two Cottonwoods and of the American Fork. For this reason a fow particulars will be in place here.

Wulfenite is found associated with calamine, (smithsonite,) cerusite, malachite, az

* There exists generally among the mining population of the central Territories of the United States a distinction between horn-silver and chloride of silver-an'error arising, as I am persuaded, from supposing the ochraceous ores to be chlorides not so perfectly developed as to be sectile.


urite, and more rarely alone in little cavities in the ochraceous ores. In the Emma mine vags or geodes are occasionally found lined with botryoidal, apple-green calamine, rarely crystallized, often brownish and sometimes colorless, but invariably associated with wulfenite. The calamino incloses and covers the crystals of wulfenite, which form a lining of considerable thickness. The wulfenite is in thin tabular crystals of a yellow color, resembling the Carinthian variety of this species. The crystals are very brilliant and perfect, but quite minute, rarely two or three millimeters in width, and not over one millimeter in thickness, often less. They are quite abundant in this association, no piece of the calamine which I bave seen being without them. They sometimes, but rarely, penetrate through the globules of the ealamine so as to show themselves on the upper surface of that species. But the calainine has obviously formed botryoidal masses around the wulfeuite, a crystal of this species being often seen forming the nucleus of the calamine gobules.

These facts are of interest in the paragenesis of these epigene species. The order of production has obviously been, first, the cerusito resting ou ochraceous iron, manganese, and other metallic oxides; next, the wulfenite crystals were deposited upon and among the crystals of cerusite, and lastly came the calamine, crystalline at first, and, as it accumulated, becoming tibrous and amorphous, completely inclosing and capping the other species.

Wulfenite occnrs also in this mine, as likewise in the Flagstaff, the Savage, and Robert Emmet, without the calamine, but never, as far as observed, without corusite aud other carbonates. In the Savage, masses of cerusite, with various oxides, are interpenetrated by the tabular crystals of wulfenite.

Although wulfenite forms a very minute factor of the entire ore-mass in these mines, by the law of mineral association it may be considered as the characteristic species of the ores of these districts, occurring in the magnesian limestones. So far as I am informed or have observed, wulfenite has not been hitherto found in any of the other mining districts of Urah; but by the same law it may be reasonably looked for whenever deposits of epigene minerals are explored in the same geological and mineralogical relations in the Wasatch range of mountains.

The oxidizing and desulphurizing agency which has acted upon the great ore-mass of the Emma inine, whatever it was, has performed its work with remarkable thorough

A careful study of its action discloses some other facts of interest in the paragenesis of species. From the appearance of numerous large blocks of ore, forming solid boulders in the general mass, a concentric arrangement is easily recognized. On breaking these masses across, the fresh fractures disclose a dark center which consists almost entirely of decomposed sulphides, composed chiefly of cerusite blackened by argeutite and metallic silver in a pulverulent form. This dark center, chiefly of cerusite, is often pseudonorph of galenite in its fracture. Next is usually a zone of yellowish and orange-yellow antimonial ocher, cervantite, often quite pulverulent, at times only staining the cerusite; then follows a narrow zone of green and blue copper-salts, malacbite, azurite, cupreous anglesite, with, rarely, wulfenite; tben follows cerusite, sometimes stained with antimony ocher, and not unfrequently associated with wulfenite; outside all are the iron and manganese ochers. This concentric arrangement I have observed in a great number of cases; and the above order of species, while not invariable, is believed to reflect accurately the general arrangement. Wellcrystallized species, as mineralogical specimens, are rare in this great mass; but the following may be recognized as its chief components:

Galenite, sphalerite, pyrite, jamesonite (1), argentite ,stephanite, boulangerite (), antimonial galenite, cercantité, mimetite (1), liinonite, wad, kaolin, lithomarge, cerusite, anglesite, liparite, wulfenite, azurite, malachite, smithsonite. Those most abundant or best crysdallized are in italics. This list can no doubt be extended as opportunity occurs for the piore careful study of the ores, the great mass of which, amounting to many thousand tons, have gone into commerce without passing under any mineralogical oye.

American Fork.—This district adjoins Little Cottonwood on the southeast. Among the principal claims are the Miller, Pittsburgh, Wyoming, Kentuck, Alpine, Silver Glance, Waterloo, Emeline, Con. queror, Champion, Chelsea, Castor, Terrible, Mary Ellen, Live Yankee and Silver Tie.

The Silver Glance is opened by two cuts, each about 25 feet long, a tunnel 120 feet long, and an incline shaft 117 feet long, with a drift from it 35 feet long. There is a large pile of ore on the dump.

The Miller. is a very large deposit of ore, on which much work has been done. It is opened by two tunnels and an incline, the largest tunnel being 60 feet in length, following a solid body of ore all the way from the surface to the heading, where it showed a vein 19 feet in thick

ness in June. At that time a portion of the mine had caved in, owing to defective timbering, but even when seeing it under this disadvantage the body of ore exposed to view appeared very large. Two miners, with pick and shovel, could easily keep two wheelbarrows brusy run ning out ore to the dump, where five men were employed sacking it up, after which it was slid down a ravine to the guleh below. From twelve to fourteen tons per day was the usual quantity taken out when worked in this way. When we consider that this ore will run from $90 to $180 per ton, and that the quantity which can be taken out when the mine is Noperly opened for working will be only limited by the means of transportation and reduction, we can hardly comprehend the true value of this mineral deposit. The surrounding mountains are thickly covered with a heavy growth of pine, sufficient to furnish fuel in abundance for many years to come.

The Wyoming lode is situated about 400 feet above the Miller, on the very crest of the mountain, and is supposed by many to be the same vein. In June a short drift had been run in ou the vein from the east face of the hill, at the end of which a shaft had been sunk to a depth of 20 feet, disclosing a vein of ore 8 feet in width. It shows nearly the same character as the Miller, being carbonate mixed with galena, as. saying at the rate of $122 per ton.

The Kentuck lode is nearly a mile further north on the same mountain. A shaft has been sunk to the depth of 25 feet from the surface, the ore-vein being about 4 feet wide in the bottom. The mineral is coarse galena and honey.combed quartz.

The Alpine mine, within a few hundred feet of the Miller, has developed a large body of ore, thought to be equal to that of the Miller. The company had about 100 tons on the dump in August. The Alpine has been pierced and laid open by a tunnel run into the side of the mountain something over 100 feet, which is well timbered, and the mine is in good condition to deliver much ore.

The Pittsburgh mine showed, in November, in an incline 43 feet deep and a cut of 12 feet, a large body of solid lead-ore, which was reported to assay $60 per ton in silver, and 69 per cent. of lead. The quantity in sight was estimated at 5,000 tons, which, it was expected, could be brought to the surface, as soon as the new tunnel should be completed, at the small cost of $1 per ton.

The Champion is opened by a shaft 60 feet deep, and by two tunnels each 100 feet deep. Galena-ores.

The Mary Ellen claim shows a mixture of galena, iron pyrites, and copper pyrites, and is said to contain gold.

The Sultana smelting-works, consisting of three furnaces, were built to work the ores of the Miller mine. They are at the junction of Miller and the main cañon. Other works are to be erected at the mouth of the cañon, and refining-works at Lehi. The foundation for a quartzmill has been laid.

The district has two recording offices, and over 500 claims had been recorded up to November, 1871.

Lucien district.This district is about one hundred and twenty-five miles west of Ogden, nearly on the line between Utah and Nevada, and six miles south of the Central Pacific Railroad. It was reported, in October last, that Messrs. Buel and Bateman had purchased the Zecoma claim in this district, a claim which carries galena, said to assay

65 ounces silver per ton, and a high percentage of lead, and that they would speedily erect a furnace for smelting the galena-ores which it yields. About 100 tons of galena are reported to have been previously

shipped West. There are also several copper-claims in this district, from which a few tons have been shipped to San Francisco.

Saint George district.-Up to April, 1871, no claims had been opened and worked in this district, though many locations had been made.

Star district, Beaver County. Up to April, 1871, the total amount of ore shipped from this district would not exceed 100 tons, and tbis from various locations. One lot worked at Ely & Raymond's Mill yielded $197 per ton in silver. This was from the Taylor mine. One shipment to San Francisco netted $250 per ton, and one lot sampled in Salt Lake City yielded $288 per ton.

Hamilton district.-A new district, southwest of Camp Floyd, was organized in September last. The quartz-croppings are reported to contain galena and some gold.

Parley's Park, a district about thirty miles east of Salt Lake City. The principal mine here is the Piñon, in which a large body of galena and carbonate has been struck. Assays are reported to yield from 30 to 250 ounces of silver per ton. The owners, Lowe & Co., are reported to have contracted to deliver 20 tons a day to the new smelting-works to be erected at Ogden. List of furnaces and mills in Utah in the latter part of the summer,

1871. Ophir, furnaces, 5; mills. 2 Salt Lake, furnaces.

4 Stockton, furnaces... 2 Bingham, furnaces

2 Tintic, furnaces.

2 American Fork, furnaces. Cottonwood, furnaces. 3) Corinne, furnaces.

1 For the following estimate of working expenses of a 15-stamp mill, with Brückner roasting-cylinders, in Utah, I am indebted to Mr. L. Huepeden, the agent of Mr. Brückner:

Estimate for 15-stamp mill in Utah, employing two Brückner-cylinder furnaces, 13 feet by 61,

(in clear.) Capacity of 20 to 30 tons.

[All these figures are high.] Labor: Engine, 4 cords, at $5, ($4)......

$20 00 Wood: Furnaces, 4 cords, at $5, ($4).

20 00 Two engineers, at $5 and $4

$9 00 Two crushers..

8 00 Foreman, (night shift).

5 00 Head amalgamator.

5 00 Two amalgamators, at $4.

8 00 Two roasters, at $5.

10 00 Two roustabouts, at $3 50..

7 00 Assayer, $6; smelter, $5....

11 00 Clerk, $4; superintendent, $20.

24 00

87 00 Salt, 8 per cent. on 20 tons, at cent......

16 00 Loes of iron...

15 00 Loss of quicksilver, 50 pounds.

40 00 Oil, grease, &c..

3 00 Charcoal and chemicals, (assays)

5 00 Wear and tear, 20 per cent., and interest 10 per cent., ($30,000).

30 00 Office expenses...

4 00 Total on 20 tons, at $12 per ton...

240 00

Tin. In the fall an effort was made to create an excitement on account of alleged discoveries of vast deposits of tin in the vicinity of

Ogden, and many poor miners were actually allured into spending considerable time and money in that district. But the “tin mines” were speedily disposed of by scientific men as a gigantic fraud on the public, and in time, I believe, to prevent serious losses by inexperienced men. The following letter of Dr. F. A. Genth, of Philadelphia, to the editor of the United States Railroad and Mining Journal, shows the nature of the “tin mines" and "ores:

DEAR SIR: In the Philadelphia Ledger of the 25th ult., and several other newspapers, appeared the following from Salt Lake City, under date of October 23: “The tin mines of Ogden are enjoying increased attention. The governor and a large party went to-day to visit then. An experienced miner and expert from Cornwall, England, reports them wonderful, and that vast quantities of ore in sight at the Star of the West, the pioneer discovery, will average 20 per cent. of fine tin. He says these discoveries are destined to work a revolution in the tin trade of the world. New discoveries are being made daily, and another claim has been bonded for $200,000."

These are certainly wonderful discoveries, and, judging from the character of the “ore," there can 'bo no doubt that it exists in vast quantities. It was my good for. tune, already over one month ago, to receive some of that which had been sent to Washington. About fourteen days ago I received a second lot for examination, and was also favored with a visit of one of the owners, who brought larger lumps, and showed some bars of tin which had been melted from the ore, and also some copper which had been tinned with the product of such smelting, operations. My specimens are undoubtedly authentic. They consist of a rock, composed of white feldspar, (probably albite,) hornblende, and a small quantity of quartz. The albite and hornblende are present in variable quantities, sometimes the one, sometimes the other predominating. Ocular inspection did not show a trace of tin; concentration of the heavier portions, by grinding the rock and washing off the lighter, and the chemical examination of the heaviest, did also show not a trace of tin. A very careful analysis and a crucible assay showed likewise total absence of tin. The specimens which I received are, therefore, no tin-ore at all, but syenito—a granite in which mica is replaced by hornblende. As undoubtedly strong efforts will be made in the East to dispose of these “valuable tinmines," I consider it my duty to make this plain statement of my experiments, and hope that all the newspapers which have helped to circulate the report about these great tin discoveries will now correct their error. Yours, very truly,


« SebelumnyaLanjutkan »