Grant County Oregon Gold Production
The Susanville district is between lat 44°41' and 44°47' N. and long 118°41' and 118°52' W., in eastern Grant County.
Most of the production from this district was from placer mining before 1900. The placers were discovered in 1864, and those along Elk Creek and along the north side of the Middle Fork of the John Day River yielded $600,000 in gold (Swartley, 1914, p. 169). These placers were inactive in 1930 (Gilluly and others, 1933, p. 117). The Badger mine, discovered in the late 1860's, was the most important lode property in the district (Swartley, 1914, p. 170), but after several years of successful operation it was closed in 1905, reopened briefly in 1922, and closed again (Gilluly and others, 1933, p. 111). Most of the recent production from the district was from dredging operations. From 1932 through 1959 the district produced 937 ounces of lode gold and 17,809 ounces of placer gold. Total production through 1959, including the estimated early placer production, was about 48,750 ounces.
Gilluly, Reed, and Park (1933, p. 106-111) described the geology and ore deposits in some detail. The country rock throughout most of the Susanville district is schist of unknown age. This was intruded by bodies of gabbro and peridotite which are now mostly altered to serpentine. A large quartz diorite mass borders the district on the north and aplitic dikes from this intrusion cut the schist and ultra-basic rocks. Higher areas in the district are capped by Columbia River Basalt. Ore deposits are fissure veins parallel to the schistosity in the country rocks. Many veins seem to be related to the aplite dikes. Quartz is the dominant gangue mineral; metallic minerals include pyrite, marcasite, arsenopyrite, chalcopyrite, pyrrhotite, sphalerite, galena, stibnite, tetrahedrite-tennantite, and chalcocite. Gold occurs in the sulfides and also as free gold.