Coal resource data from published sources and company files were used by the Bureau of Mines to determine the location and extent of strippable coal reserves in Wyoming. Total strippable reserves of 23 billion tons were estimated in seven major coal areas. Seven large strip mining operations were active in 1969, and their production totaled 4 1/2 million tons of coal. Cutoffs used to define strippable reserves were (1) minimum coalbed thicknesses of 5 feet; (2) overburden-to-coal ratios of less than 10 cubic yards of overburden per ton of coal, and (3) total overburden thicknesses of less than 120 feet, except where reserves occur in multiple beds or a single thick bed. Tertiary rocks along margins of the Powder River Basin contain most of the strippable coal reserves in Wyoming. The wyo-Dak beds ranging in combined thickness from 30 to 130 feet, crop out on the east flank of the basin and contain an estimated 19 billion tons of strippable subbituminous c-rank coals under less than 200 feet of overburden. Partings between these beds total less than 60 feet. The 100- to 200-foot-thick healy bed on the western flank of the basin and the 35-foot-thick school and 20-foot-thick badger beds on the south also contain large strippable reserves. Elsewhere in Wyoming, strippable deposits are subbituminous coal of late Cretaceous and Tertiary ages, mostly in the Hanna and Great Divide Basins in the south-central portion of the state and in the Kremmerer-Hamms Fork Region in the southwestern corner.