San Miguel County Colorado Gold Production
The Mount Wilson district is in southeastern San Miguel County on one of the western spurs of Mount Wilson.
The Silver Pick mine, which was the only property of importance in the district, was located in 1882 and was worked steadily until 1909. Its period of greatest productivity was from 1882 to 1906, when ore worth $750,000 was mined. Purington (1898, p. 847) noted that some ore was worth as much as $100 to $150 per ton, with gold as the major constituent and silver and lead as minor constituents. The Silver Pick and most of the smaller mines were idle from 1909 through 1959, except for small-scale activity from 1932 through 1941 when about 520 ounces of gold was produced. Total gold production of the district through 1959 was roughly 24,800 ounces.
The oldest rock unit of the district is the Mancos Shale of Cretaceous age. This is overlain in turn by the Telluride Conglomerate, the San Juan Tuff, and the Silverton Volcanic Series, all of Tertiary age. The main mass of Mount Wilson is a stock which ranges in composition from granogabbro to quartz monzonite. The intrusive cuts rocks as young as the Silverton Volcanic Series, and thus is the youngest bedrock unit of the district (C. S. Bromfield, oral commun., 1963).
The ore deposits are in quartz veins containing pyrite, chalcopyrite, arsenopyrite, galena, sphalerite, tetrahedrite, stibnite, and calcite. Most of the gold is believed to be contained in chalcopyrite, galena, and arsenopyrite. The most productive veins, including the Silver Pick, are in the stock; however, a few veins of minor importance are in the invaded sedimentary rocks near the intrusive contact (C. S. Bromfield, oral commun., 1963).
OPHIR DISTRICT
The Ophir district, in eastern San Miguel County, includes the area south of San Miguel River, west of Bridal Veil Creek, and the Ophir Valley on the south. This district includes the Iron Springs, Ames, and South Telluride mining areas.
Mines in the Ophir Valley were operating as early as 1878, and the ore was shipped to the Silverton smelter (Henderson, 1926, p. 53). In 1879 two arrastres were built in the vicinity of Ophir. In 1883 a small smelter was built at the old town of Ames, but it was unsuccessful and was operated for only a year (Henderson, 1926, p. 216). According to H. C. Burchard, as quoted by Henderson (1926, p. 217-218), several mines including the Alta, the largest producer in the district, were developed as early as 1881. According to D. J. Varnes (in Vanderwilt and others, 1947, p. 427), the history of the district has been one of intermittent production except for a few large mines which operated fairly continuously. Most of the ore mined early from this district was rich in silver, and activity of the camp depended in part on the price of silver. Some mines, which were idle most of the time, became substantial producers during times of favorable metal prices. The district was almost idle from 1930 through 1936, was substantially active from 1937 through 1948, and was idle again from 1949 through 1959.
Production records are fragmentary and the amount of gold is usually included with the value of other metals (D. J. Varnes, in Vanderwilt and others, 1947, p. 427). The total gold output of the district through 1959 was probably a minimum of 200,000 ounces.