50 



GEOPHYSICAL METHODS IN MINING 



[Chap. 5 



methods may be used. Extensive magnetic surveys have been conducted 

 on gold deposits of similar type in the Witwatersrand fields of South 

 Africa, where the suboutcrop of the gold series could be traced by virtue 



Deposit 



Ti/pe Locality 

 (6nptii/ii(d 

 or Snioqitol) 



deelif/c Form 



Beopliijsical 

 Ueltiod 



direct I struct. 



I. h^aqmotic Differenfiation Deposits 



Diamonds 



Platinum ) % ^ 

 Chromile j 



Magnetite 



Sulpftide 

 Ores 



Arkansas 

 Urals 

 Quebec 



Kiruna, Urals. 

 Colorado 



Nickel ores, 

 Sudburif 



ma<fn. 



elect 

 maqn. 

 (qrote) 



magn. 

 maffi 

 mofaf?) 



II tleteroqenetic Solution Deposits 



Contact -metamorptiic: 

 ^ Mofnetlle; SpeclHem. 

 ■ lead. Zinc 

 % Copper 



% 



dold- Silver Sulphides 

 Lead ■Silver; Baryte 

 Timpten.Fluorite 

 Siderite. Moli/Uenite 

 QBart/6^e^infikiieas 



lead' Zinc 

 Ores 



NewMex.. Saronq 

 New Met. 

 NewMex., Arizona 



Calif., Nevada. 



Canada 

 Cola.. Illinois 

 N.liex. 



4fp^ Onhrio.Bniit 

 etc 



iffssauri 



magn. 

 elect 



elect 



■ elect 

 elect. 



] elect 

 elHtjnag. 



mefn. 

 groK 



Fig. 5-1o. Genetic classification of mineral deposits and applications of geophysical 



methods. 



of its association with magnetic shales. Reflection-seismic and electrical 

 methods likewise hold promise in this area for structural investigations. 



Much geophysical work has been done on the type of mineral deposits 

 classified above in group II (heterogenetic solution deposits). An example 



