Reconnaissance for uranium in asphalt-bearing rocks in the western states

Abstract

An appraisal of asphalt-bearing rocks as potential sources of uranium was made during 1953 and 1954 by examining deposits in 45 areas in California, Utah, Wyoming, Montana, New Mexico, Texas, Oklahoma, and Missouri. A total of 202 samples from these areas was analyzed for uranium. The oldest rocks sampled are Ordovician in age, and the youngest are Recent. Although none of the deposits are of value at this time as a source of uranium, some of the deposits may constitute a low grade uranium resource whose recovery will depend upon the primary use to which the asphalt is placed. Significant amounts of uranium in the ash of the extracted oil were found in samples from 7 of the 45 areas examined. These areas are Chalone Creek, McKittrick, Edna, and Los Alamos areas, California: Vernal area, Utah; Sulphur area, Oklahoma; and the Ellis area, Missouri. The average uranium content of samples from these seven areas ranges: from 0.028 to 0.376 percent in the ash of the extracted oil. All except the Chalone Creek area contain large estimated reserves of asphalt-bearing rock, ranging from 15,000,000 to almost 2,000,000,000 tons. The average uranium content of samples from 13 additional areas ranges from 0.020 to 0.068 percent in the ash of the extracted oil. Many of these areas contain very large reserves of asphalt-bearing rocks. Evaluation of field data indicates that naturally occurring asphalts with a relatively high uranium content probably originated in, or migrated through, rocks that contain more than average amounts of uranium. It is believed that some of the uranium was present as an original constituent of the oil but that some uranium may have been introduced during migration of the oil.