Strategic Minerals Geophysical Research--Chromite And Potash Studies

Since the early 1970's, the U.S. Geological Survey (USGS) has carried out exploration geophysical research on non-basemetal strategic mineral commodities, including uranium, lithium, gold, potash, and chromite. The chromite study (largely completed) and the potash study (still going on) carried out during the past 4 years have not been aimed at the discovery of new ore reserves, but instead were designed to complement exploration by private mining companies. The USGS has carried out research not normally conducted by these companies, but which can be used by them in their efforts to increase production of strategic minerals. Results of the chromite and potash studies highlight the importance of: 1) a laboratory-research phase (petrophysical and petrographic studies) at the beginning of work on any new commodity; 2) an operative or functional ore-deposition model to serve as a conceptual framework, and the necessity to continually test, refine, and modify it during the study; 3) indirect geologic/geochemical indicators, secondary associations, and the use of multiple physical properties; and 4) the use of a systematic inverse-cost sequential-exploration (i.e. lowest resolution and lowest cost first) strategy to keen the exploration economically reasonable. The keystone to the success of the study is frequent and substantive dialogue among geologists, geophysicists, and geochemists.