Rock Creek/Montanore (Libby)

Region West, Northwest
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Red-bed copper-silver deposits.
Identified resources None.
Production None.
Status Past exploration; Hecla acquired the Montanore project in September 2016.
Estimated resources Montanore prospect (2011): Cut-off 1.0 oz/st Ag: Measured 4,026,000 tons @ 1.85 oz/st Ag and 0.74% Cu yielding 7,463,000 oz Ag and 59,712,000 lbs Cu; Indicated 77,480,000 tons @ 2.05 oz/st Ag and 0.75% Cu, yielding 158,840,000 oz Ag and 1,169,270,000 lbs Cu; Inferred 35,080,000 tons @ 1.85 oz/st Ag and 0.71% Cu, yielding 65,060,000 oz Ag and 497,520,000 lbs Cu (Kaye and Challiner, 2011).
Geologic maps Vuke and others (2007), scale 1:500,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric data.
Favorable rocks and structures Contiguous, shallow-dipping ore body that can be traced throughout the Cabinet Mountains. Silver-copper mineralization is stratabound in the upper part of the lower Revette Formation.
Deposits Montanore prospect (MRDS dep_id: 10048814), Rock Creek (MRDS dep_id: 10048813).
Evidence from mineral occurrences MRDS; Montana Bureau of Mines and Geology Mining Archives; Gammons and others (2020).
Geochemical evidence Sulfides at Montanore include minor to trace amounts of galena, digenite, covellite, tetrahedrite, gersdorffite, and molybdenite.
Geophysical evidence None.
Evidence from other sources Unknown.
Comments The Montanore project is located approximately 23 miles south of Libby. This is one of largest Ag deposits in U.S., ranking behind only Couer d'Alene, Idaho and Butte, Montana. Montamore is the 20th largest Ag deposit in world.
Cover thickness and description Unknown.
Authors Kaleb C. Scarberry.
New data needs Geologic mapping, geophysical, and geochemical surveys.
Geologic mapping and modeling needs Geologic mapping.
Geophysical survey and modeling needs High resolution geophysical survey.
Digital elevation data needs Lidar inadequate.