Lander County Nevada Gold Production
The Battle Mountain district, in northwestern Lander County, includes the Battle Mountain Range, an area 15 miles long and 12 miles wide. The town of Battle Mountain is the supply center.
The district was organized in 1866 after ores rich in silver and copper were found (Hill, 1915, p. 71-72). By 1885 the district was mostly inactive, but it revived slightly in 1900 and gold prospects created a mild flurry about 1910. The demand for copper during World War I stimulated activity, but after 1918, the copper mines were worked only intermittently. In 1932 additional gold discoveries led to increased production (Vanderburg, 1939, p. 19).
In the earlier years, the gold produced in the Battle Mountain district was a byproduct of copper and silver ores, but in more recent years the deposits were mined chiefly for their gold and the copper and silver were byproducts.
Data on gold production before 1902 were not found. From 1902 through 1936, a total of 47,633 ounces of placer gold and 27,173 ounces of lode and byproduct gold was mined (Vanderburg, 1939, p. 20). From 1937 to 1958, a total of 62,082 ounces of lode and byproduct and 12,484 ounces of placer gold was produced. Total recorded gold production through 1959 was 149,372 ounces.
The Battle Mountains are composed primarily of Paleozoic sedimentary rocks which are, from bottom to top: black shale and white quartzite, 900 to 1,000 feet thick; red sandstone, 1,500 feet thick; and limestone of probable Pennsylvanian age, 2,000 feet thick (Hill, 1915, p. 66-76). Dikes and sheets of intrusive granite porphyry, monzonite, and quartz diorite, of possible Late Cretaceous or early Tertiary age, cut the sedimentary rocks. Volcanic rocks —rhyolite and augite andesite—cap the mountains locally. The ore deposits occur along simple fissures or wide shear zones in the complexly folded and faulted sedimentary rocks. There are four mineralogic vein groups:
- Silver-lead deposits—mostly fracture filling in the sedimentary rocks—that contain galena, sphalerite, pyrite, and tetrahedrite. Some veins contain a zone of secondary enrichment that consists of polybasite, pyrargyrite, argentite, and tetrahedrite. Near the surface these veins were oxidized, and cerussite was the most abundant ore mineral.
- Copper deposits—slightly auriferous copper ores in fractures in sediments. The ore, some of which is oxidized, consists of chalcopyrite, pyrite, sphalerite, and galena, associated with contact metamorphic minerals.
- Gold deposits—iron-stained quartz veins carrying free gold and pyrite.
- Antimony deposits—quartz-stibnite veins in sediments.