544 



UNITED STATES MINERAL RESOURCES 



other deposits should be indirectly applicable in the 

 search for potential platinum resources. 



PROBLEMS FOR RESEARCH 



Whereas base metals can be located by geochemical 

 prospecting of stream sediments and soils and by 

 geobotanical and geophysical methods, the discovery 

 of platinum metals nearly always requires a direct 

 chemical analysis of samples of the ore deposit. 

 Nevertheless no laboratories can yet provide accurate 

 results for all six platinum-group elements using a 

 single analytical method, when these metals are pres- 

 ent at concentrations less than 10 ppm. Methods do 

 exist for Pt, Pd, and Rh down to the low part-per- 

 billion range (Haffty and Riley, 1968) . 



Indirect techniques needed to help locate platinum 

 metals will require research into the chemical and 

 physical behavior of platinum metals in the weather- 

 ing and transportation cycles. Research on the geo- 

 physical parameters of platiniferous zones in known 

 occurrences is also necessary as a prelude to develop- 

 ing useful geophysical prospecting techniques. Trace- 

 element studies of platinum metals are also necessary 

 to define pathfinder elements. 



A complete study of the nature and behavior of 

 platinum metals should also be undertaken with the 

 purpose of defining presumably unknown geological 

 environments where these metals may be found. 



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