Uranium in the East Walker River Area, Lyon County, Nevada

Abstract

Uraniferous quartz veins and deposits of other types occur in an area at least six miles long and three miles wide, along the East Walker River in Lyon County, Nevada. Most of the deposits are on the west side of the river. Six properties of areas were mapped, sampled, and tested radiometrically. These properties are: the Far West Willys group, North-west Willys group, West Willys group, Silver Pick property, Grant View hot springs, and the Boerlin ranch radioactive area. The East Walker River area is underlain by coarse-grained porphyritic granite. Cutting the granite are numerous aplite dikes and a few perthite-quartz pegmatites. Faulting was noted in a few places. Radioactive material has been found in the East Walker River area in deposits of four types: (1) quartz veins carrying small amounts of copper, lead, and silver minerals; (2) partly altered granite adjacent to quartz veins; (3) gouge zones, and (4) hot springs. The quartz vein deposits are the most abundant. The uranium minerals pitchblende and kasolite occur in the quartz veins, in aggregates and streaks associated with copper and silver minerals, galena, and barite. In many quartz veins abnormal radioactivity is absent or only locally present. Samples collected from quartz veins contained from 0.001 to 0.14 percent uranium; only five of 46 samples contained over 0.025 percent uranium. Partially altered granite adjacent to the quartz veins in the West Willys No. 7 property contains scattered torbernite, but the highest uranium content noted in deposits of this type was 0.006 percent. The third type of deposit is represented on the Silver Pick property, where a gouge zone of differing thickness contains scattered flakes of torbernite. Five samples from this deposit contained from 0.00.5 to 0.013 percent uranium. The Grant View hot spring is moderately radioactive near the point where it issues from the hillside. Laboratory analysis of both water and sand from this deposit shows little uranium content (0.02 parts per million), and little radioactivity, indicating that the radioactivity is due to some short-lived daughter product, probably radon . The uraniferous material found to date in the area is of too low a grade and small a size to be of present value.