Mercur, USGS, 1932
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Mercur, USGS, 1932
Geology And Ore Deposits Of The Stockton And Fairfield Quadrangles, Utah
By James Gilluly.
(from USGS Professional Paper 173, published 1932, pages 122-139)
(Download the full edition, 236 pages, one page at a time, from the HathiTrust) (not available from the USGS website)
Camp Floyd (Mercur) District
[Pages 122-139; excerpts only]
[edited to fix obvious typographical errors]
[122]
The history of the Camp Floyd or Mercur district has been summarized to 1917 by Heikes, and no activity has been reported in the district since his summary was written.
[Pages 122-127 - Direct quote from Heikes, as included in the 1920 USGS Professional Paper 111]
(Read the Heikes summary as part of USGS PP 111, 1920)
[Pages 137-139]
[137]
The Mines, Camp Floyd District, Mercur Area
Consolidated Mercur
The Consolidated Mercur mines were located at Mercur, the principal workings on the south side of Mercur Canyon but other workings on the north side. The company owned about 944 acres of mining claims, of which about 400 acres was in the principal mineralized belt of the camp. The mines, when active, were served by the Salt Lake & Mercur Railroad, which connected by way of Manning Canyon with the Los Angeles & Salt Lake Railroad at Fairfield Junction. The railroad was dismantled in 1914.
[138]
Developments and production. — The mines of the Mercur area were all caved and inaccessible at the time of this survey in 1926, having been abandoned in 1913. No accurate maps of the developments of the property were available, but it is known that the workings were very extensive and ran to many thousands of feet. The total output of the Consolidated Mercur Mines Co. and its predecessors, the Delamar Mercur Co. and the Mercur Gold Mining & Milling Co., was 4,336,621 tons of ore, yielding about $16,500,000 in gold. Dividends amounted to $3,445,312.
Geyser-Marion
The Geyser-Marion mine (Franklin lease) is just north of the Mercur town site. It is one of the oldest mines in the district. The Marion mill was the first in the district, operating on silver ores in 1872-1873, 1880, and 1889. In 1893 it was changed to a cyanide plant equipped to treat 50 tons of gold ore a day. The adjoining Geyser mine was combined with the Marion in 1897, but the property did not prosper and was sold at sheriff's sale shortly after 1900. It was later operated as the Franklin lease up to 1913 but was not a success. The total production of gold was probably about $500,000.
Like the other mines at Mercur, the Geyser-Marion was caved and inaccessible at the time of this survey in 1926, so that no new information was obtained regarding it. No map of the workings was obtainable, but they were rather extensive. The mine is known to be in the same stratigraphic horizons as the Consolidated Mercur mines, and its ore was also very like that of the Consolidated Mercur.
Sacramento
The Sacramento mine is about three-quarters of a mile southwest of Mercur, in the gulch draining the north slope of Sunrise Hill. The mine began commercial operations in 1895. It operated for about 12 years, during which about $1,500,000 in gold and over 3,000 flasks of mercury were produced. It was the only mine of the district from which mercury was obtained commercially. The workings are inaccessible, but the a map, kindly supplied by former officials of the mine, shows that they were rather extensive. About 600,000 tons of ore was extracted.
The mine is in the lower part of the "Great Blue" limestone, at the same stratigraphic horizons as the Consolidated Mercur mines. The beds dip about 30 degrees East, on the east limb of the Ophir anticline. The porphyry intrusion of Sunrise Hill cuts through the western part of the mine. The ore is reported to have resembled that of the Consolidated Mercur mines but carried a considerably greater proportion of mercury, some assays running 8 per cent.
Sunshine Area
Overland
The Overland mine is about half a mile northeast of the Sunshine, on the east side of Overland Gulch. It was operated at intervals from 1898 to 1905, in the last years under a receiver. The production is estimated at $219,646, from 156,000 tons of ore.
The mine is developed on the upper levels by an inclined shaft and on the lower levels by a vertical shaft which cut the ore bed at 1,600 feet on the dip. The mine is in the "Great Blue" limestone beneath the Long Trail shale member, on the east flank of the Ophir anticline, where the dip is about 35 degrees to 40 degrees East. The workings were inaccessible in 1926, and no description of them can be given. The ore is described as practically identical with that at Mercur.
Sunshine
The Sunshine mine is just south of the town of Sunshine, a little more than 3 miles south of Mercur. It operated from December, 1895, to October, 1896, for a short time in 1898-1899, in 1902, and in 1909-1910, when it was closed, the ore supply being considered exhausted. The total production is believed to have been about $221,000 in gold.
The mine is just below the Long Trail shale member of the "Great Blue" limestone and was developed by an incline trending North 75 degrees East, and having a slope of 32 degrees, with the bedding, which dips east, on the east limb of the Ophir anticline. The mine was badly caved at the time of this survey, in 1926, and but little of it was accessible. The ore appears to have occurred at two horizons, approximately 150 feet apart stratigraphically, each immediately beneath a carbonaceous shale bed. Some fissures trending North 45 degrees West, were followed by drifts. Presumably the ore was associated with these fissures, but this is not known to be true.
The ore greatly resembled that at Mercur but was in beds lying somewhat higher in the stratigraphic column.
[139]
West Mercur Or West Dip Area
Daisy (Norma)
The Daisy mine, later renamed the Norma, is just south of the abandoned site of West Mercur. It was discovered shortly after the first successful gold mining in the Mercur district, and construction of a mill was begun in 1897. It was the first mine at West Mercur to ship cyanide precipitates, but little success was attained and in February, 1900, the mine was handed over to the miners for them to earn their back wages from it.
[Note: Howard, L. O., Cyanidation in the Mercur district of Utah; Salt Lake Mining Review, October, 1913.]
In July, 1900, it went into the hands of a receiver. It was overhauled at various times in later years, and the company was finally reorganized as the Norma Gold Mining Co. Operations were renewed in 1913, but the mine has been abandoned since the complete destruction of the mill by fire in 1917.
The mine was developed by two inclined shafts, each about 700 feet deep, with numerous drifts connecting them. The shafts were sunk along the West Mercur fault with the "Great Blue" limestone as the footwall and Quaternary alluvium as the hanging wall, at least for the few score feet of the shafts that are now accessible. The mine is caved almost to the surface, and no new information regarding its geology was obtained during this survey. The ore is described by former employees of the mine as strongly resembling that of Mercur. It occurred along the West Mercur fault, presumably associated with this fault rather than any particularly favorable bed.
The ore ran between $4 and $8 to the ton. It was difficult to treat. The production of the mine was somewhat more than $75,000.
La Cigale
The La Cigale mine is about a mile north of the abandoned site of West Mercur and about 4 miles west of Mercur. It was first developed in 1897 by three inclined shafts along the West Mercur fault, with levels at 100 and 260 feet below the surface. It is not known what additional development work was done in the two years following, but the mine was abandoned at the end of 1899. In 1926 it was so badly caved that the workings were inaccessible. The workings have been described by R. V. Thompson as localized along a shear zone, and certainly the shafts expose and follow the West Mercur fault, so that presumably the ore was related to this major fault. The fault dips west and as far down the incline as can be seen, about 150 feet, exposes only alluvium in the hanging wall. The long strike distance through which the fault zone was assayed and found to be mineralized leads to the conclusions that the fault was probably of pre-mineral age and that the mineralization was not confined to certain beds as at Mercur but extended to the breccia zone along the fault. However, the "Great Blue" limestone, which forms the footwall of the fault, dips essentially parallel to it, so that the localization of the ore along the fault may possibly have been fortuitous and due merely to accidental coincidence with a susceptible limestone bed. The horizon in the "Great Blue" limestone just below the fault is much higher than that of the productive strata at Mercur, being several hundred feet above the Long Trail shale member instead of below it.
The ore is described as essentially the same as that of Mercur, and assay values averaging over $6 a ton were reported by the company. In view of the success of the Mercur mines with ore of this grade, it is probable that such assays were not truly representative of the ore as mined, for if they were the venture should have prospered better than it did.
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