Some Present-Day Problems And Possibilities In Mining Geophysics

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Journal Article: Some Present-Day Problems And Possibilities In Mining Geophysics

In answer to the basic question "What is mining geophysics all about?" it is contended that only an a posteriori distribution of ore reserves can be established in the present state of our knowledge and that it is pointless to talk about a priori distributions. The role of mining geophysics in minimizing costs of exploration is emphasized by means of examples drawn from electromagnetic-magnetic, refraction seismic and extra-detailed magnetic surveys. Drilling in mining operations can be successfully directed by using the mise-a-lamasse method as illustrated by a drillhole survey of this type in north. Sweden. Drillhole self-potential measurements can be used to estimate the depth extent of orebodies. An example from the U.S.S.R. also shows that well developed SP patterns are present underground even if there is no surface manifestation of an SP anomaly. The problem of prospecting for orebodies under a highly conductive overburden is discussed and it is pointed out that either a multi-frequency or a transient-field method of electro-magnetic prospecting must be resorted to and that although there are at present technical advantages in the transient-field method, the ultimate advantage probably rests with a multi-frequency technique. A method, here called the contact polarization curve (CPC) method, that has been developed in the U.S.S.R. is presented in outline. Its principle is to earth a current electrode in an orebody and detect the potential jumps as the electrochemical barriers corresponding to different electronically conducting minerals are exceeded when the current is continuously increased. The method can be used to estimate the total surface area of an orebody or the total surface area of mineralized grains in an impregnation-type ore. The geothermal method is briefly touched upon and it is pointed out that it may be a potentially useful method in the search for zinc ores.

D. S. Parasnis

Published Journal 
Geoexploration, 1974



D. S. Parasnis. 1974. Some Present-Day Problems And Possibilities In Mining Geophysics. Geoexploration. (!) .