Geology and mineral resources in the Macho mining district, Sierra County, New Mexico
Virginia T. McLemore
The Macho mining district is southwest of the Lake Valley mining district in the eastern foothills of the Mimbres Mountains and was discovered about 1879. Volcanic-epithermal veins along faults in the Tertiary Macho Andesite strike northsouth to N40°E and are steeply dipping to the west. Production from these veins amounted to 61 oz Au, 20,000 oz Ag, 679,000 lbs Pb, and 11,000 lbs Zn from 1879 to 1977. Grades of ore shipments ranged from 5 to 23.7 oz/short ton (0.1-0.7 g/mt) Ag and 3 to 50% Pb with minor amounts of Au (<0.16 oz/short ton or 0.005 g/mt), Zn (5-11%), Cu (0.02-0.3%), and V (<10%). In addition, collected samples from this district contained 136-1,086 ppm As, 3-41 ppm Mo, 1-233 ppm Cd, and 5-64 ppm Bi. Drilling in 1983 by Nicor Minerals Ventures, Inc. indicated that mineralized zones occur in the Fusselman Dolomite 1,097- 1,128 m below the volcanic-epithermal veins. Additional mineral potential is probably present in the district, but more drilling is required along strike of the veins and within the mineralized structures to better evaluate the mineral resource potential.
- McLemore, Virginia T., 2012, Geology and mineral resources in the Macho mining district, Sierra County, New Mexico, in: Geology of the Warm Springs region, Lucas, Spencer G.; McLemore, Virginia T.; Lueth, Virgil W.; Spielmann, Justin A.; Krainer, Karl, New Mexico Geological Society, Guidebook, 63rd Field Conference, pp. 541-546.