Hole-To-Hole Geophysical Measurement Research For Mineral Exploration

A major deficiency exists in state-of-the-art borehole geophysical measurements available to the mineral industry-- the inability of conventional well-logging techniques to "see"more than a few meters from a borehole. Hole-to-hole and hole-to-surface geophysical measurements offer the possibility of extending the range of investigation to 3–300 m. A review of previous research indicates that a few extended-range borehole geophysical techniques have been developed for specialized problems in petroleum and mineral exploration. Two new applications show special promise: hole-to-hole electrical measurements for uranium exploration and hole-to-hole seismic measurements for coal-seam testing. Results of recent field tests and computer model studies indicate that these techniques can improve exploration efficiency by reducing the number of drill holes needed for finding uranium ore bodies and by certifying the continuity of coal seams.