Uranium

Uranium is used as fuel for nuclear power plants, where the energy released from nuclear fission is converted to electricity. Nuclear reactors account for about 20% of total U.S. electrical power generation. Because nearly 90% of the uranium used by nuclear power plants is imported, domestic sources of uranium will be critical should world markets and imports be disrupted.

Uranium minerals have been discovered at many localities throughout Montana. Host rocks include: vein deposits and pegmatite dikes, limestone collapse breccias, uraniferous lignites, phosphatic rocks of the Permian Phosphoria Formation, placer sand and gravels,and sandstone “roll-front” deposits.

During the 1950s and 1960s, small amounts of uranium were surface-mined from limestone breccias in the Pryor Mountains and from vein deposits in the Boulder Batholith. Roll-front deposits in Lower Cretaceous sandstones of southeastern Montana were explored via drilling in the 1970s; the data and geophysical logs are stored at the MBMG Billings office. Future uranium mining in Montana could include in situ recovery (ISR) of these roll-front deposits. During ISR, injection wells are drilled to the target formation and used to inject a solution to dissolve and mobilize the uranium minerals. Production wells pump the solution back to the surface where the uranium is recovered.

Potential sources for uranium and other elements vital to energy production, such as rare earth elements, continue to be investigated by MBMG through the USGS EarthMRI program.