The Fleecer Mountain district is not known for its mineral production. Indeed, only two mineral developments have been described in the mining literature. Both the Bonanza and the Cayuga claims were described in the 1910s. Development work for the mines was modest and no production was reported.
The Fleecer Mountain area is distinguished by Paleozoic quartzites and limestone that are intruded by quartz monzonite similar to the nearby Boulder batholith. Contact ores have developed in the sedimentary formations (Winchell 1914).
BOUNDARIES OF THE DISTRICT
Winchell (1914) in his discussion of the nearby Divide district, places the Fleecer on the west side of Divide Creek, southwest of Feely. The area is distinguished from the Divide Creek district by a different geology. The Fleecer district is named after the mountain that occupies the area between Divide Creek, Jerry Creek and the Big Hole River. Figure 1 shows the district as defined by the AMRB (1994) and a smaller district as defined by Winchell (1914).
Sahinen (1935) does not place the district nor does Lyden (1948) or Wolle (1963).
HISTORIES OF SELECTED MINES
The Bonanza group of claims is on the western slope of Fleecer Mountain at an elevation of about 8,500 feet. On the Bonanza claim, an adit 350 feet long was driven into quartzite. The mine followed the contact of the quartzite above limestone. Above the tunnel is an inclined shaft. The principal metals in the ore are gold and silver with some copper. The mine sought to exploit faults on the bedding plane deposits. One such fault was black talc from a shaley, bituminuous limestone. There is no record of production (Winchell 1914).
The Cayuga mine is located in section 6, T1S, R9W, two miles northwest of Divide on the southeast slope of Fleecer Mountain. The mine was located on a contact between the quartz monzonite of the Boulder batholith and sedimentary rocks of Mesozoic age. Copper ore from the mine consisted of malachite, cuprite, melaconite, chrysocolla and a little azurite in a silicious grantic gangue. At the time the mine was described, the mine had not reached sulphide ores (Winchell 1914).
The mine was visited in 1911 by J. T. Pardee. He described the development as a timbered double-compartment shaft 125 feet deep that was equipped with a horse whim. The development also included an open cut and short incline a few feet north of the shaft. The dump held about two tons of material. An average sample from the dump assayed at 14.84 percent copper (J. T. Pardee 1913).
On the nearby Shannon claim a caved shaft was observed. The dump showed decomposed garnet rock, massive limonite, and vein quartz stained with copper. There is no record of production from the group of claims (J. T. Pardee 1913).
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
Lyden, Charles J.
1948 "The Gold Placers of Montana", Montana Bureau of Mines and Geology Memoir 26. Montana School of Mines, Butte.
Pardee, Joseph Thomas
1913 "Coal in the Tertiary Lake Beds of Southwestern Montana",
U. S. Geol. Surv.
, Bull. 531-G, pp. 229-244.
Sahinen, Uuno M.
1935 "Mining Districts of Montana", Thesis, 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
Wolle, Muriel Sibell
1963 Montana Pay Dirt. Sage Books, Athens, Ohio