DIAMOND: OCCURRENCE IN INDIA 143 



younger beds of any thickness, they are inaccessible to the natives, whose appliances for the 

 sinking of shafts and other mining operations are few and primitive ; moreover, in such 

 cases the cost of working would be prohibitive, and the mining of the diamonds can only be 

 effected where the strata crop out on the surface of hill-sides, the workings penetrating to 

 only a very small depth even in these more favourable situations. 



Where the diamond-bearing bed lies at a small depth below the surface, a pit or shaft 

 of a few square feet or yards in section is sunk to meet the desired bed, the shaft being 

 usually about 20 feet, rarely 30 feet, and in a few cases 50 feet in depth. The workings at 

 the bottom of the pit extend only to such distances as the stability of the material overhead 

 will permit. The diamantiferous rock so obtained is, when necessary, carefully broken up, 

 and the diamonds obtained from it by washing and sorting in the same manner as from the 

 loose sands and gravels. 



The excavation of the hard, solid beds of sandstone which often overlie the 

 diamantiferous stratum is a matter of no small difficulty to the worker whose tools are 

 inadequate for the purpose. In a few districts the difficulty is somewhat lessened by the 

 employment of a device often made use of by the old German miners. A large fire is 

 kindled on the spot at which it is desired to sink a shaft, and when the rock below is 

 strongly heated, it is suddenly cooled by the application of cold water. This causes the 

 rock to crack in many places, and thus the work of excavation is rendered less arduous. 



Diamantiferous sandstone, which has been removed from its natural bed, and from 

 which diamonds have been extricated, is often allowed to be exposed to the various 

 atmospheric weathering agencies for some time, and is then again worked over, when a 

 further yield of diamonds may be given, this being sometimes repeated several times. This 

 fact has given rise to a belief among the natives that this second crop of diamonds has 

 originated in the waste rock, or that it is the result of a fusion together of the smaller 

 diamonds originally left behind ; similar beliefs are also met with in South Africa. The 

 actual explanation, of course, lies in the fact that during the interval in which the waste 

 rock is exposed to the air, weathering takes place, and any stones which may have been 

 embedded in the larger fragments of rock are thus set free and easily picked out by the 

 searchers. A mass of rock which has once been worked over will naturally be the poorer 

 both in the number and the size of the diamonds it contains. In spite of this, however, 

 the refuse heaps from old diamond mines are in many places at the present time being 

 continually turned over and diamonds as continually found. 



C. Ritter arranged the Indian diamond mines known to him in five groups, according 

 to their geographical distribution, and described them in order from south to north. In 

 what foUows this grouping will be adopted, the smaller mining districts not mentioned by 

 Ritter being introduced in appropriate places, and information derived from later reports, 

 especially those of V. Ball, incorporated with the matter given by Ritter. A rather 

 different grouping of the mines is given by Ball. The map (Fig. 33) shows the distribution 

 of the diamond-fields in India. 



1, The Cuddapah Group on the Penner River. 



This group includes the most southerly mines, those furthest to the east are in the 

 neighbourhood of Cuddapah on the river Penner, where numerous mines have been worked 

 for several centuries with varying success. At the present time the majority of the mines 

 in this group — perhaps, at times, the whole of them — are abandoned, but this by no means 

 indicates that the supply of diamonds has been completely exhausted. The spot at which 



