Geology and Production History of the Big Chief Uranium Mine, Navajo County, Arizona

The Big Chief Mine was one of six uranium mines located on the eastern flank of the Oljeto syncline in the Monument Valley area of Navajo County, Arizona, and developed during the 1950's by the Industrial Uranium Company of Salt Lake City, Utah. Of these six mines (Big Chief, Moonlight, Starlight, Starlight East, Sunlight, and Sunlight South), the Big Chief was the shallowest and produced the least uranium (Table 1). A map of the underground workings (Figure 1) and other data pertaining to the Big Chief Mine were recently located in the files of the U.S. Geological Survey (USGS) at the Denver Federal Center.l Warren 1. Finch of the USGS permitted me to copy the map for the Arizona Geological Survey. Most of the information in this report is from U.S. Atomic Energy Commission (AEC) documents. John J. Borkert, a former mining engineer with the Industrial Uranium Company of Salt Lake City, Utah, supplied pertinent details about the mine.