Jeffrey J. Daniels

Borehole Resistivity And Electromagnetic Methods Applied to Mineral Exploration

Electrical methods using buried transmitters or receivers have become increasingly important exploration tools as exploration for deep mineral deposits has increased. A variety of resistivity methods have been developed and tested for borehole applications to mineral exploration, from simple mise-a-la-masse hole-to-surface arrays to more complicated hole-to-hole arrays. Time and frequency domain EM systems are currently being used principally for detecting the presence of massive conductors in resistive host rocks. Successful tests of hole-to-hole resistivity measurements for detecting old mine workings in a coal seam and hole-to-surface resistivity methods for determining the continuity of a mineralized zone are discussed in this paper. An example is shown of a surface-to-hole EM system that was used in an ore district near Sudbury, Canada to detect the presence of massive sulfide mineralization that was previously missed by exploratory drilling.