SHALLOW GEOPHYSICS AND ITS BENEFITS ON THE DELINEATION OF IN SITU URANIUM MINING; PRELIMINARY STUDIES

Geophysics is important because it provides a continuous line of data quickly and at lower cost than lines of drilled wells. Necessary in situ parameters include mudstone seals above and below the ore deposit capable of maintaining a pressure of 45 psi during production equivalent to a water table at least 30 meters above the ore body.

In this project previously drilled uranium roll fronts in the Paleocene Fort Union and Wasatch Formations were targeted and tested again with shallow geophysics tools. That data was compared with Gamma Ray, Resistivity, and SP well log data to determine the precision and accuracy of shallow geophysics technology in locating sandstones (host reservoirs), mudstones (seals), and the water table (hydrostatic head).

The tools used include the AGI SuperSting R8/IP/S/WIFI unit using 275 meter linear array of electrodes with a 3.6 second recording time for Electric Resistivity, as well as the Noggin 100 and 250 MHz Ground Penetrating Radar which were pulled along the project line.

As a result, lithologic identification is presently possible down to 60 meters below surface with electrical resistivity. Currently, lithologic identification is only possible down to 5 meters below surface using ground penetrating radar in clay poor (sandstone rich) areas. Further GPR data will be collected as the weather improves (equipment is not functional below -15 degrees Celsius). Identification of water table is yet to be determined (still processing).

Further testing may include adjustment of energy source, increase of line length, and improved processing techniques. Target depth for usable data is 120 meters. Additional tools such as a magnetometer and gravimeter may also be tested. The primary goal is to determine quickly and cheaply if a specific shallow uranium ore deposit (<100 meters) can be mined by in situ leach methods or if classic mining by removing and milling is required. Funding and instruments for this project were provided by EPSCoR and WyCEHG of University of Wyoming in conjunction with Casper College. Thanks to Stakeholder Energy, Casper, Wy and the Allemand Ranch for access to uranium data and the surface locations.