Precambrian Franklin Mountain tin

Region West, Southwest
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Quartz veins with cassiterite up to 3 ft wide extending 1,000-2,000 ft in exposed granite outcrop. See Price and others (1983).
Identified resources Historical production of tin.
Production Eight tons of pure Sn metal was smelted in a small mill after ore was discovered in 1899. Production ceased in 1912 (Harbour, 1972, p. 76-77).
Status Small past mining operations.
Estimated resources Ore is of high quality, and the cassiterite is easily concentrated and smelted, but the veins are thin and lenticular, and the reserves may be small (Harbour, 1972).
Geologic maps Lucia (2010), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Precambrian granite.
Deposits El Paso mine (MRDS dep_id: 10085695), Franklin Mountain tin deposits (MRDS dep_id: 10154673; USMIN Site_ID: TX00011).
Evidence from mineral occurrences MRDS; USMIN.
Geochemical evidence Ore consists of cassiterite in disseminated crystals and massive chunks in quartz veins and surrounding granite. The granite consists almost entirely of fine- to medium-grained quartz and orthoclase; cassiterite appears to replace both minerals. Scattered crystals of wolframite, fluorite, topaz, tourmaline, and pyrite are associated with ore (Harbour, 1972).
Geophysical evidence No data.
Evidence from other sources Old prospect data, and early 20th century prospecting.
Comments Only tin ore that has been mined commercially in the State of Texas.
Cover thickness and description Deposits may be present at the surface or at depth in mapped sedimentary rocks or concealed by Cenozoic basin fill.
Authors Brent A. Elliott, Laurel G. Woodruff.
New data needs New mapping, high resolution geophysics.
Geologic mapping and modeling needs Geologic mapping at a scale of 1:24,000.
Geophysical survey and modeling needs High resolution aeromagnetic survey would be useful for tracing subsurface geology and structures.
Digital elevation data needs Lidar adequate.