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DEEP ORE EXPLORATION BY ELECTRICAL METHODS
Author(s) -
BRAEKKEN H.
Publication year - 1961
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1961.tb01126.x
Subject(s) - prospecting , geology , equipotential , drill , drill hole , drilling , iron ore , equipotential surface , current (fluid) , geophysical prospecting , geophysics , mining engineering , mineralogy , mechanical engineering , metallurgy , electrical engineering , geometry , engineering , materials science , oceanography , mathematics
A bstract It has been found that ore prospecting by suitable electromagnetic and electrical methods may under favourable conditions—such as occur in parts of Norway—be carried out to greater depths than have so far been realized. By 500 c.p.s. electromagnetic measurements at the surface there was located a deep ore body, occurring in the continuation of, but separate from, an old ore body, which had been worked down to its end at a depth of some 500 m. The new ore body, starting at a depth of some 700 m and continuing downward with a slightly more dipping axis, has been traced over a considerable distance by further electromagnetic measurements at the surface, with the energizing current led directly to the ore in drill holes. Possibilities, problems and further improvements in deep E.M. techniques of measurement and interpretation are discussed. By D.C. equipotential mapping at the surface, with the current led directly to the ore, the location and direction of the deep ore body was established in agreement with the electromagnetic findings. Problems and developments in deep Charged Potential prospecting and interpretation are discussed. By 500 c.p.s. electromagnetic and D.C. potential measurements in drill holes essential information has been achieved both in locating ore formations beside a drill hole and in deciding whether ore formations in different drill holes are connected or not.