MEMOIRS 



OF 



THE GEOLOGICAL SURVEY OF INDIA. 



The Kolar Gold-Field, being a description of 

 Quartz-Mining and Gold-Recovery as practised 

 in India, by F. H. Hatch, Ph.D., Assoc. M. Inst. C.E., 

 F.G.S. Mining Specialist, Geological Survey of India, 



INTRODUCTION. 



As a field for the scientific study of the geology of vejn-deposits 

 or for an enquiry into the technical processes of gold-recovery, the 

 Kolar gold mines have, perhaps, exceptional advantages. The lodes 

 show in full clearness the characteristic phenomena of quartz veins, 

 such as the limitation of the pay-ore to well-defined "chutes", and 

 present in addition unusual and interesting structural features, such as 

 the formation of enriched and enlarged zones of pay-ore along folds 

 in the plane of the vein; while both underground and on surface the 

 mining properties are sufficiently equipped with plant and machinery 

 for the successful exploitation and metallurgical treatment of this 

 class of gold ores. 



Modern mining at Kolar dates from the year 1 88 1 ; but long 

 before that the search for gold, and no doubt its successful exploita- 

 tion, had been conducted by ancient native miners, as is abundantly 

 testified by the existence of extensive old workings, some of which 

 were carried to a depth of close on 300 feet. In this fact, as well as 

 in general geological features, the field bears a striking resemblance 



