Mercur, USGS, 1895
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Mercur, USGS, 1895
Economic Geology Of The Mercur Mining District, Utah.
By S. F. Emmons.
[351]
Economic Resources.
Discovery And Development Of Mining Districts.
(Download the full edition, 147 pages, from the Internet Archive)
[Pages 351-359; excerpts only]
[edited to fix obvious typographical errors]
Although, according to Bancroft, the existence of silver ores in the neighborhood of Great Salt Lake was known as early as 1857, the mining industry of Utah cannot be said to have come into existence until 1869, when the advent of the transcontinental railroad and the consequent influx of Gentiles brought capital and enterprise to its aid.
[Note: History of Utah, by H. H. Bancroft, San Francisco, 1890, p. 741.]
[352]
It is to General P. E. Connor, who commanded the California volunteers stationed at Fort Douglas, overlooking Salt Lake City, during the civil war, that credit is generally given for the first authentic discovery of silver ores in the Territory.
In 1863 General Connor found deposits of argentiferous galena at Little Cottonwood Canyon in the Wasatch Mountains, and on the west side of the Oquirrh Mountains, near the present town of Stockton. Others of his command discovered in the same year ores carrying lead and silver in Bingham Canyon, on the eastern slopes of the latter range, 20 miles southwest of Salt Lake City.
In December of the same year the West Mountain mining district was organized. It at first included the whole Oquirrh Range west of Jordan Valley; but later the western slopes were segregated under the name of the Rush Valley district, and the former name was retained for the eastern slopes, the working mines of which were confined practically to Bingham Canyon. Still later (1870) the western region was further divided into the Tooele, Rush Valley or Stockton, and Ophir or East Canyon districts.
In the Stockton district smelting furnaces were erected in 1864 by General Connor and his associates, and when at the close of the war the volunteer forces were disbanded, many of their members went into mining around Stockton, which gave to that town a fitful prosperity. With the failure of the smelting operations, which was a necessary result of the unfavorable economic conditions under which they were inaugurated, the district soon retrograded. In later developments the sanguine expectations of its discoverers have not been realized, though one mine has proved an important and heavy producer. Some exceptionally rich ores were found in Ophir Canyon, and the discoveries extended into the neighboring districts. Dry Canyon on the north and Lion Hill on the south formed part of the Ophir district; the indications of ore were traced still further south from the latter point, and in 1869 a small mining camp, called Lewiston, had already been started in the canyon of the same name, about 4 miles due south of Ophir. As the inhabitants drew their supplies of food largely from the neighboring settlement of Camp Floyd, the district was generally known as the Camp Floyd district.
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The production of the Stockton district has extended over a longer period than that of either the Ophir or Bingham, but has been very irregular, and is very much less in aggregate amount.
Still less important has been the Camp Floyd (or Lewiston) district. During the ten years from 1871 to 1881 it has probably produced about 46,000 ounces of silver, which is the total mineral production of the camp for that time, since the ores then worked contained no lead, copper, or gold. The gold production of its successor, the Mercur district, which became important in 1892, amounted in that and the succeeding year to about 19,000 ounces, and as the gold ore is quite free from silver and lead, this is also the total production of the camp for that time.
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In estimating the commercial value of this product, with gold at $20 per ounce and silver at $0.73 per ounce, the total value of the Oquirrh ores for 1893 was $2,730,100, while that of the ores from the rest of Utah was $2,745,230; so that, considered in this way, the Oquirrh districts have furnished half the precious metal product of the Territory.
Camp Floyd Or Mercur Mining District.
Although the town of Lewiston was already established as a mining camp in 1869, but little prospecting seems to have been done until 1870 or later.
The following is the first notice of the district that appears in print:
[Note: Mineral Resources west of Rocky Mountains for the year 1871, R. W. Raymond, Washington, 1873, p. 313.]
Camp Floyd district. - This district adjoins Ophir or East Canyon district on the south. It is comparatively new and the claims are not yet much developed. The outcroppings of veins are well defined and are not so high up on the mountain as at Lion Hill. The winters are not so severe, and it is claimed that miners can work in open claims during the season. Among the principal claims are the Sparrowhawk, Silver Cloud (reported to have been recently sold to an English company), Mormon Chief, and the Grecian Bend. There is also a vein affording cinnabar of low percentage.
[Cinnabar is a bright scarlet-to-brick-red mineral composed of mercury sulfide, serving as the primary ore for refining elemental mercury. Cinnabar has historically been used to create the brilliant red pigment known as "vermilion", and was widely used in Chinese, Persian, and other cultures for lacquerware and ornamental items. Cinnabar is toxic due to its mercury content. It is most hazardous when heated or in powdered form. Modern "vermilion" paint is a safer, synthetic substitute.]
Sparrowhawk. - This claim, opened during the summer by Mr. McMasters, shows a considerable body of shaly quartz of a dull, bluish-gray color, and coated with films of chloride of silver. The vein is marked by very heavy quartz croppings. The thickness at the open cut, from which most of the silver-bearing ore has been taken, is about 50 feet, but it is irregular. A large portion of these croppings is apparently quite free from ore in paying quantity. In August last year there was a large pile of ore on the dump, estimated at 100 tons of first-class and the same quantity of second-class ore.
Grecian Bend. - This claim is a short distance beyond the Sparrowhawk and may be a prolongation of the same vein. This and the Mormon Chief claim beyond it are adjoining claims, each having 2,000 feet upon the lode. They are characterized by an enormous outcrop of quartz, stretching up the side of the mountain for a mile or more. It rises from 20 to 50 feet or more in height, and has an irregularly broken, precipitous face. It pitches into the hill at an angle of about 20 degrees, and the general direction of the cropping is 10 degrees south of west. This outcrop is in general quite hard and compact, and gives little indication of being ore bearing, though the color is dark, and it much resembles the quartz at the Sparrowhawk claim, where chloride of silver has been found. Very little work has been done on either of these claims. With the exception of two small pits upon the lower edge of the cropping, the mass of the vein is untouched and awaits vigorous work, conducted upon a liberal scale, to break into the rocky mass and show whether it is ore bearing or not. At one of the excavations there are some small streaks of ore, which, it is said, assay well for silver. At that place the ledge appears to be split up into several layers, but all of them are conformable to the strata of shaly limestone above and below. The indications are sufficient to justify the expenditure of some money in prospecting the ground, especially along the contact of quartz with the wall rocks.
[357]
In the same reports, for the year 1872 (p. 255), it is said that an English company which had acquired the Sparrowhawk, Last Chance, and Marion mines had worked them actively, employing 40 to 50 miners, and that the company had also built a 20-stamp null, capable of reducing 30 tons of ore per day. The developments of free-milling ore in the Mormon Chief, Grecian Bend, Silver Cloud, Star of the West, Stafford, Carrie Steele, and other mines are also spoken of in the most encouraging terms, and a second stamp mill is said to have been recently completed at Fairfield.
The United States report on Mineral Resources for the year 1873 (p. 276) notes that the mill of the English company had ceased running on its own ores, because "they are very difficult to sort, and of too low grade to pay for extraction without sorting." In the description of the mineral composition of the ores no mention is made of the antimony with which they are impregnated, nor of the possibility that it may have been the presence of this metal that interfered with the amalgamation. The mill worked during the year mainly on custom ores, and it is said to have produced, up to the end of November, 56 bars of bullion, worth over $52,000, while the tailings on hand were worth $40,000. The camp probably reached its maximum production of silver during this year (1873), for which 11,000 ounces are reported. In 1874 the mining operations are reported to have been unimportant; the mill was running on custom ores.
For the next seven or eight years a small but somewhat continuous production of silver is reported, probably obtained from small bodies of chloride ore near the surface. The average annual output of the camp during the period of its former activity may be estimated at about 4,000 ounces.
Early in the eighties the camp became almost entirely deserted, and of the town of Lewiston only a house or two remained. So completely was it forgotten that the name was given by the postal authorities to another town in Cache County, Utah, and when mining revived, some ten years later, a new name had to be given to it.
The mines mentioned in the above reports are the silver mines, which are now completely abandoned. The projecting outcrop of dark, siliceous rock in which the silver ores were found still goes by the name of the Silver Ledge. The occurrence of gold, which constitutes the present value of the camp, was not mentioned in the above-quoted reports, although it is evident that the gold-bearing ores were noticed by the early explorers.
The report on Mineral Resources for 1873 has the following:
In Camp Floyd several deposits of cinnabar have been discovered. On the Jenny Lind an incline 50 feet deep has been sunk. Experiments made with several hundred pounds of ore gave the average percentage of quicksilver in the assorted stuff as 4 per cent. The New Idria is located on the same vein as the one just mentioned. In a 20-foot incline sunk on it 4 feet of ore are reported to be exposed. It has the same value as that from the Jenny Lind.
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From this and the mention in the quotation from the report for 1871 of a "vein affording cinnabar of low percentage," it is evident that what is now known as the Gold Ledge, which is but a hundred feet or so above the Silver Ledge, had been remarked, but its gold contents had evidently not been suspected. This is hardly surprising, considering the usually low percentage of this metal, and the fact that it is never visible in the ores, even with the aid of a glass.
About 1890 interest in the camp was revived through the discovery that at an horizon about 100 feet above the Silver Ledge, or stratum from which the antimonial silver ores of the early days had been extracted, a line of decomposed ocherous-looking rock, often stained red by cinnabar or realgar, carried a small but very persistent percentage of gold.
[Realgar is an arsenic sulfide mineral, often referred to as "ruby of arsenic" or "ruby sulfur". It was historically used as a brilliant orange-red pigment in paints and varnishes. As a source of arsenic, it is highly toxic and was historically used to create poisons. Modern orange-red pigments are synthetic and not based on realgar.]
The old and generally abandoned claims were bought up and consolidated into several groups. The most important company of the present day had a number of claims on the south side of the ravine immediately above the site of the old town. One of these claims was called the Mercur, probably on account of the occurrence of cinnabar, or mercuric sulphide, on the outcrop of the Gold Ledge within its limits. From this the company and the little town that soon grew up derived their names.
The managers of the Mercur Company for some time found considerable difficulty in devising a process which would reduce their ore at a profit. It was of too low grade and too free from fusible metals, like lead to be profitably smelted. Repeated attempts at amalgamation were unsuccessful, and it is said that in the mill at first erected to treat the ores they yielded less than the amount of the running expenses. Successful experiments were finally made with the MacArthur-Forrest cyanide process, which dissolves the gold in a solution of cyanide of potassium, from which it is precipitated by peculiarly prepared shavings of metallic zinc.
On account of the scarcity of water the leaching mill was not erected in Lewiston Canyon, near the mine, but in Fairfield Canyon, 3 or 4 miles distant, and halfway to Fairfield Station. Here a spring furnishes a fine flow of water from a bed of shale at the base of the alternating siliceous and calcareous strata which are folded into a syncline in the bed of Pole Canyon.
In this mill the treatment of the ore, which is little else than a decomposed limestone or porphyry, has proved most successful. In practice it is very coarsely crushed for leaching, so that the tailings are large pieces of rock about half an inch in diameter. Hence, in spite of the expense of hauling the ores on poor roads over the divide separating the two canyons, they have paid very generously to their owners.
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In 1892 the Mercur mine produced upward of 4,000 ounces of gold, and up to November, 1894, the company had paid $175,000 in dividends.
In 1893 the Marion mine, formed by the consolidation of the Sparrowhawk, Marion, and other claims which in former days had been extensively worked for silver, became productive. Its workings are situated on the north side of the gulch directly opposite the claims of the Mercur mine, and the spurs on which these two working mines are located are known from them as Mercur and Marion hills respectively. At the east foot of Marion Hill, and just north of the town, a mill was built for treating the ores of the Marion mine by the cyanide process. This mill has been running successfully ever since, and, it is claimed, can profitably treat an ore carrying only $4 in gold per ton. Water for the mill is obtained from the Sparrowhawk spring, with which it is connected by about 2 miles of pipe. The Sparrowhawk spring is situated on the same belt of water-bearing shale as the Mercur spring, but several miles to the northwest, near the summit of the divide over which the road from Mercur to Ophir passes.
The production of the district for 1893, which is the combined product of the Mercur and Marion mines, was between 14,000 and 15,000 ounces of gold.
In the summer of 1894 the Geyser Company, whose claims are situated on the northeast side of Marion Hill, commenced work upon another cyanide mill, situated a few hundred yards above the Marion mill. This was finished too late in the season to permit much production. The scarcity of water is a decided obstacle to milling in the canyon, for there is no running water, and the known springs have a limited supply of water and are all taken up. There are two water-bearing belts that cross the canyon, which are indicated on the accompanying geological map. On the upper of these belts are the Mercur, Sparrowhawk, and Franklin springs; on the lower the Silver Cloud and Surprise springs are the only ones that have yet been developed.
At the time of examination (October-November, 1894) the grading of a branch railroad destined to connect the Mercur mine and mill with the Union Pacific Railroad at Fairfield junction was nearly completed. It is to be expected that with the completion of this railroad some of the other claims may be more vigorously explored for deposits of gold-bearing ore and be eventually added to the list of producing mines.
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