The Ruby Mountains, while active as a talc producer in recent years, has had no metallic ore production. Indeed, the district has seen only a few mineral prospects claimed for copper and iron and none for precious metals.

This area is underlain by Precambrian gneiss and schist, but Paleozoic and Mesozoic rock, as well as Tertiary volcanic rocks crop out at the north end of the Blacktail Mountains. A small bridge of metamorphic rocks connects the Ruby Range with the Greenhorn Range to the east. The Ruby Range is surrounded by intermontain basins partially filled with Tertiary sediments. Paleozoic and younger sedimentary rocks are exposed only in the northern part of the Ruby Range. The area contains typical metamorphic mineral resources. Specific minerals include: talc, graphite, sillimanite, corundum, iron, manganese and pegmatite minerals. Some nickel and asbestos deposits have also been located, but were not of commercial size or grade (Geach 1972; Berg 1979).

The area has been prospected for copper, but only small uneconomical deposits have been located. On Hoffman Creek a deposit consisting of chalcopyrite and pyrhotite in calcite was located on the Log Cabin Claim (Geach 1972).

An iron deposit was located on Carter Creek in 1948. The large deposit holds large ore reserves, but had not produced any ore by 1972 (Geach 1972).

The district has numerous bodies of talc. The Treasure, Beaverhead, Keystone (Regal), American Chemet, Estelle (Sweetwater), Banning-Jones, Bozo-Zobo, Sauerbier are among the most prominent. None of these mines appears to be historic (Berg 1979).


Sahinen (1935) does not mention this district nor does Lyden (1948) in their overviews of Montana mining history.

Geach (1972) in his report on mines in Beaverhead county defines the Ruby Mountain mining region to include the Ruby Mountains and the Blacktail Mountains. Figure 1 shows the district as defined by the AMRB (1994) which is similar to the definition by Geach (1972).


Onyx Mountain

Located in southeast section 4, T9S, R5W, the Onyx Mountain mine is typical of the small unpatented mines in the district. The mine development consists of an adit, loading platform, stockpiles and waste dump. The mine was estimated to be from the 1930's and has left little historical evidence beyond that required for a claim. The mine was of a minimalist construction and development. Two other small adits were also observed on the same mountain slope (Earle 1981).


Abandoned Mine Reclamation Bureau (AMRB)

1994 Mining districts of Montana. Maps 1:100,000 and Map #94-NRIS-129. Compiled and edited by Joel Chavez. Prepared by Montana State Library Natural Resource Information System (NRIS) for Montana Department of State Lands. Helena

Berg, Richard B.

1979 "Talc and Chlorite Deposits in Montana", MBMG Memoir # 45.

Bowman, A. H. and Barclay Craighead

1926 Montana, Resources and Opportunities Edition, Vol. 1. Department of Agriculture, Labor and Industry, Division of Publicity.

Earle, B. J.

1981 "Onyx Mountain Mine Adit - 24MA65" Antiquites Site Inventory

Geach, R. D.

1972 "Mines and Mineral Deposits (except fuels) Beaverhead County, Montana", Montana Bureau of Mines and Geology, Bulletin 85.

Knopf, Adolph

1933 "Pyrometasomatic Deposits: Ore Deposits of the Western Stats (Lingren Volume), pp. 537-557, American Mining and Metallic Engineering.

Kriegel, W. Wurth, and John D. Keys

1935 "Ceramic Materials and Products that have Present or Future Significance in Montana", a radio talk, Montana School of Mines.

Lyden, Charles J.

1948 The Gold Places of Montana. Montana Bureau of Mines and Geology Memoir No. 26. Montana School of Mines. Butte.

Winchell, Alexander Newton

1914 "Mining Districts of the Dillon Quadrangle, Montana and Adjacent Areas", U. S. Geological Survey, Bulletin 574.


1904 "Famous Old Madison County, Montana", Mining World, Vol. 21, No. 2, pp. 32-35.


1911 "Gold Dredging Near Ruby, Montana", Eng. and Min. Journal, Vol. 91, pp. 812-815.