Carmen Creek Mining District, Lemhi County, Idaho, USAi

Regional Level Types
Carmen Creek Mining District	Mining District
Lemhi County	County
Idaho	State
USA	Country

The Carmen Creek District covers an area extending from the headwaters of Carmen Creek to the headwaters of Freeman Creek.

According to Umpleby (1913, p. 125), mining began in the district about 1897 when the Oro Cache mine was opened. A 10-stamp mill was built shortly thereafter and ore was processed until 1907. Between 1902 and 1914, 3,972 tons of ore were mined. During 1910, a small Ford quartz mill was installed at the Carmen mine to process gold ore discovered in 1904. The Silver Star deposit was located in 1902 and in 1938, a 150 ton per day flotation mill was constructed. Production from the Silver Star between 1925 and 1975 is estimated to be 691 ounces of gold, 6,286 ounces of silver, 6,791 pounds of copper, and 30,788 pounds of lead (Mitchell, 1995f, p. 5).

Mineralization in the district consists of several types. A copper- and gold bearing exhalite zone, a few tens of meters thick, is located at the transition between the Middle Yellowjacket (argillite and quartzite) and the Upper Yellowjacket (quartzite) at the Carmen mine. The copper and gold are concentrated in lenses of massive quartz and magnetite. At the Oro Cache mine, quartz veins striking northeast and dipping steeply northwest in argillaceous quartzite contain pyrite, chalcopyrite, galena, sphalerite, and native gold. A fracture zone, 40 to 50 feet wide, strikes northeast and dips steeply southeast in quartzite at the Silver Star deposit. Breccia in the zone consists of angular fragments of quartzite cemented by white quartz which is locally drusy. Galena, sphalerite, tetrahedrite, chalcopyrite, and pyrite occur disseminated and as pods in the matrix (Anderson, 1959, p. 84).

Significant resources were identified by Plexis Gold during a drilling program conducted at the Silver Star. According to Nisbet (personal communication. Formation Capital Corp., 1995), the deposit contains 250,000 ounces of gold.