Western Molybdenum Company mine, Chewelah district, Stevens County, Washington

The Western Molybdenum Company mine was opened many years ago to obtain copper. The only production was several cars of crude copper ore shipped during World War I. An unsuccessful attempt to produce molybdenum was made in 1939-1941.

The deposit consists of steeply dipping, northeast-striking veins in monzonite and marble, carrying molybdenite, pyrite, chalcopyrite, scheelite, and some quartz. Northwest- striking faults cut and offset the veins as much as 10 feet. The main vein, which contains all the known ore, is developed by four levels to a depth of 293 feet. It contains ore shoots from a few inches to 4 feet wide and up to 130 feet long, carrying about 1 percent MoS₂, 1 percent Cu, and 0.15 percent W0₃.