New Mexico Geological Society Annual Spring Meeting — Abstracts

During a period of nearly three decades (1951–1980), the Grants uranium district in northwestern New Mexico yielded more uranium than any other district in the United States, thereby making New Mexico a major producer of uranium. Today, uranium is used primarily in nuclear reactors to produce electricity via nuclear fission. Although no producing operations exist in New Mexico today, numerous companies have acquired uranium properties within the Grants, Hook Ranch-Riley, and Red Basin-Pietown districts and plan to explore and develop deposits in the future. The Grants district is a large area in the San Juan Basin, extending from east of Laguna to west of Gallup, and includes eight subdistricts. The Grants district is probably 7th in total world uranium production behind East Germany, Athabasca Basin in Canada, Australia, South Africa, Russia, and Kazakhstan. Other areas in New Mexico have potential for uranium. The most important deposits in the state are within the sandstones of the Jurassic Morrison Formation in the Grants district. More than 340 million pounds of U₃O₈ have been produced from Morrison Formation deposits from 1948–2002, accounting for 97% of the total production in New Mexico and more than 30% of the total production in the U.S. An estimated additional 406 million pounds of U₃O₈ remain in historic reserves in unmined deposits. Three types of uranium deposits are in the Westwater Canyon Member of the Morrison Formation: (1) primary, tabular (trend or blanket), (2) redistributed (roll-type or stack), and (3) remnant-primary sandstone. A fourth type, tabular sandstone uranium-vanadium deposits, is found in the Salt Wash and Recapture Members of the Morrison Formation in the western San Juan Basin. Other types of uranium deposits are found in New Mexico, but have not been major producers. Several companies are planning to mine these deposits by in situ recovery or conventional mining and milling methods. Other areas outside of the Grants district in New Mexico have been examined for uranium potential and some of these areas yielded minor production and have future potential. Exploration has occurred during the last decade in the Hook Ranch-Riley and Red Basin-Pietown districts, and at least one deposit has reported potential resources. Other basins in New Mexico, such as the Las Vegas, Sabinoso, Nacimiento, Chama, and Hagan-La Bajada basins and at Mesa Portales should be evaluated for sandstone uranium deposits. Although worldwide, other types of uranium deposits are higher in grade and larger in tonnage, the Grants district has been a significant source of uranium and has the potential to become an important future source, as low-cost technologies, such as in situ recovery techniques improve, and as demand for uranium increases, thereby increasing the price of uranium. Molybdenum, selenium, and vanadium were produced as by-products at the mill and could be recovered by conventional milling in the future.