Abstract: A low-level airborne radioactivity survey of parts of Beaverhead and Madison Counties in southwestern Montana was undertaken from June 6 to October 14, 1955. Flying centered around the Ruby Range-Sweetwater Basin area and concentrated on the Precambrian metamorphic complex and Tertiary lake-bed sediments. No commercial uranium deposits were discovered, and no extensions were found of the few known small occurrences. Five areas of high background detected through the survey were investigated on the ground.

Introduction: During the year 1952-1953, research on the Boulder batholith program was largely devoted to basic mineralogy studies of the "siliceous reef" and, to the extent possible at that time, the "base metal" deposits.

Abstract: The Free Enterprise property is located in the Boulder mining district, Jefferson County, Montana. Secondary uranium minerals occur here in small irregular concentrations in and adjacent to a narrow silicified fracture zone in quartz monzonite.