CHAPTER 13 



SUBSURFACE AND OFFICE REPRESENTATION 

 IN MINING GEOLOGY* 



SIGURD KERMIT HERNESS 



The problems of geologic field and office map representation have 

 been present since at least the time of Agricola, who lived in the sixteenth 

 century. It was only towards the close of the nineteenth century that prac- 

 tical techniques of detailed mapping came into use in the industrial exploi- 

 tation of mineral deposits. Winchell's mapping system, developed towards 

 the close of the nineteenth century and still in use at Butte, Montana, was 

 one of the first applications of detailed mapping to ore exploration. Since 

 that time, the men interested in hard-rock geology have been too preoccu- 

 pied with the theoretical and physiochemical abstract theories to continue 

 research in bettering such techniques, and as a consequence the Winchell 

 system is still in general use without modification. 



The techniques and system evolved as a result of the writer's research 

 has departed to a large extent from the Winchell system as used at Butte. 

 The system has been gradually and carefully developed on the basis of 

 logic and of trial-and-error methods. It is believed that this system per- 

 mits far more detailed representation than any now in use and that the 

 results are a saving in mapping time and expenditures. Because of the 

 greater detail possible and the maximum utilization of graphic and colori- 

 metric representation of qualitative and quantitative values it is believed 

 that greater utilization of geologic data with consequent increased ore 

 finding efficiency is obtained. It is hoped that continued research in repre- 

 sentation technique will eventually introduce a better understanding of 

 geologic processes such as the genesis and localization controls of ore 

 deposits. 



It is desirable that men who have been trained in this system will 

 initiate its installation at properties where they accept employment, and 

 that they will make efforts to improve upon the system. It is expensive to 

 change mapping systems at large mines, once certain mapping techniques 

 have been long established; therefore, when a mining property is in its 

 infancy or youth, it is important that great caution be taken that every de- 

 tail of a proposed mapping system will work towards the most efficient 

 utilization of geologic data. Any geologist who accepts employment 

 should assume that the property will eventually develop into a large-scale 

 operation (even though the contrary is usually true) and must, therefore, 

 exercise great care and judgment in the initiation of mapping technique 



* This paper is a preliminary and partial release of material fiom a Doctor's thesis on mining-geology 

 representation. 



