Geology of uranium in coaly carbonaceous rocks

Radionuclides in US coals

“…The result of these discoveries was a general reconnaissance search for uranium-bearing, coaly carbonaceous rocks in several western states by USGS in cooperation with the U.S. Atomic Energy Commission (AEC) during the years 1951-1954(Denson, 1959Vine, 1962). Emphasis was placed on finding coal in beds of mineable thickness, depth, and , grade that could be used as fuel and from which uranium could be extracted as an ash byproduct.…”

“…Experiments by Moore (1954) showed that low rank c n a l s (liqntfe and subbituminous) are more effective in extracting uranium from solution than are anthracitic or bituminous coals. No significant deposits of uranium in bituminous or anthracitic coals are known in the U.S.; deposits in excess of 50 ppm uranium rarely exceed a few tons in size (Vine, 1962). In fact, the uranium content of higher rank coals rarely exceeds 10 ppm (Abernathy and Gibson, 1963).…”

“…Uranium is often concentrated in the top or bottom few inches of thick beds of lignite or subbituminous coal near the contacts of the coal seam with sandstone or shale (Vine, 1962;Lacy et al, 1979;Mohan et al, 19822. …”

Principal uranium deposits of the world

“…Uranium occurs chiefly in a 0.6-to 1.2-meter-thick bed of impure lignite, which is about 207 meters above the base of the Sentinel Butte Member of the Fort Union Formation. As much as 30 meters of sandstone overlies the mineralized bed and protects it from weathering (Vine, 1962). The uranium is disseminated in the carbonaceous material.…”

“…Locally, however, green or yellow secondary minerals do occur as films and crusts on joint faces of the lignite. Only uraninite occurs in the unoxidized state; the others (autunite, bassetite, sabugal ite-sal eeite?, saleeite, and hydrogen-autunite; Vine, 1962) occur in the oxidized or partly oxidized state.…”