Ch. 27] SEARCH FOR NEW DEPOSITS 493 



requires an exacting prediction, which is admittedly beyond most 

 geological theory. Inadequate as existing theory may be in pinpoint 

 prediction, however, it forms the best guide available in the search 

 for mineral deposits. But its application often requires more courage 

 than can be mustered, and even a geologist sometimes organizes the 

 search on a "gold is where you find it" basis. 



The exploration for mineral deposits is of two general types: (1) 

 searching for new deposits or new districts, and (2) searching for ex- 

 tensions of known deposits or for additional deposits in a going mine 

 or district. 



THE SEARCH FOR NEW DEPOSITS 



In the past, the search for new metalliferous deposits and for de- 

 posits of many of the more valuable non-metals has been conducted 

 almost exclusively by prospectors. In fact, most of the deposits cur- 

 rently mined were discovered by prospectors or are extensions of mines 

 or prospects discovered by them. The prospector's theories may not 

 have been valid, but their methods were exemplary, at least in their 

 thoroughness. They covered the ground in great detail, tested any 

 specimen that looked unusual, and, especially important, confidently 

 dug test pits, sank shafts, or drove tunnels to explore the slightest 

 "showing." Risk capital, in the form of time and back-breaking 

 labor, they possessed and used more fearlessly than do mineral in- 

 vestors of the type ordinarily recognized. 



Although the prospector has all but disappeared from this country, 

 his discoveries are still the chief leads followed in the search for new 

 deposits. The common practice in seeking a new property is to com- 

 pile, through a study of the literature or through contacts with various 

 individuals or associations, a list of the localities where the mineral in 

 question has been reported, and then examine those properties or, at 

 least, such of them as appear promising. In other words, the search 

 for new deposits usually begins with examination of a known deposit, 

 which probably has been examined superficially at least by a score 

 of other geologists and engineers. Geological principles are thus in- 

 frequently applied, even now, to the search for new deposits. 



The search for the less valuable non-metallics, such as construction 

 and fluxing materials, constitutes perhaps the most notable exception 

 to the above statements, possibly because those materials are about 

 the only ones which, because of their extremely low unit value and the 

 critical importance of their location with respect to construction or 

 plant sites, did not attract the interest of the prospector. Regardless 

 of the reason, it is true that the present search for them is demanding 



