Uranium-bearing deposits west of Clancey, Jefferson County, Montana

Nine uranium deposits occur in a small area vest of Clancey,Jefferson County, Mont. These deposits are all in or near silicifiedfracture zones in quarts monsonite and related rocks of the Boulderbatholith. The deposits contain pockets of uranium minerals in cavities in brecciated silicified rock. The primary uranium mineral pitch-blende has been found in one pod. Secondary uranium minerals occur as fracture linings and in pore spaces in and adjacent to the silicified zones.

Uranium in the Clancey district was deposited probably during oneof the later of at least four periods of silicification. The quartsmonsonite, rather than the younger alaskitic dike rocks, is the host rock of the deposits.

Newmont Mining Corp. has leased the properties containing theuranium deposits and has begun development of one of these deposits.