Uranium occurrences at the Moonlight Mine and Granite Point claims, Humboldt County, Nevada

Abstract

The Moonlight mine and Granite Foint claims are on the western flank of the Double H Mountains between the Kings River and Quinn, River valleys in northern Humboldt County, Nev. Uranium minerals at the Moonlight mine occur in a vein in intensely altered Tertiary volcanic rocks. The knovm uranium mineralization is spotty and erratic, but ore-grade material is present in the vein. Samples of the vein taken along its outcrop and in the mine shaft contain from less than 0.02 percent to 0.40 percent U308. The uranium minerals change from autunite at the surface to torbernite, 'gummite(?)' and pitchblende below the 90-foot level of the shaft. The Granite Point claims are two miles north of the Moonlight mine at the base of a rhyolite cliff. Radioactivity traverses made along the base and slope of the rhyolite cliff indicate that a large part of the rhyolite is abnormally radioactive. Radioactivity ranges from 0.013 to 0.3 mr/hr and averaged 0.10 mr/hr. in the vicinity of the claims. A sample taken at the base of the rhyolite cliff, at the point of highest radioactivity c6ntains 0.02 percent U3O8.