28 HATCH : THE KOLAR GOLD-FIELD. 



lifts. Thus in Wallroth's shaft, Ooregum Mine, the water accumulat- 

 ing on the 1,060-foot level is dealt with by a Worthington high-lift 

 duplex pump having 14-inch air-cylinders, 41-inch plungers and a 

 10-inch stroke. By this pump the supply can be delivered to the 

 Cornish lifts, which extend only to the 700-foot level. 



Ventilation. — In those mines where connection has been made 

 between two or more shafts, the ventilation by natural circulation 

 of air is good. In long drives and rises where there is no natural 

 circulation, the air from the exhaust of the machine drills, driven by 

 compressed air, keeps up a supply of oxygen sufficient for working, 

 if not always for comfort. 



Illumination. — Candle-light is at present the usual method of 

 illumination underground. When the electricity supplied to the 

 mines by the Cauvery power scheme becomes available, no doubt 

 electric light will be used for the lighting of main stations and main 

 cross-cuts throughout the mines ; at present only the Champion Reef 

 has electric light underground. The cost of candles in the Mysore 

 Mine during 1899 averaged 5^. and in the Nundydroog Mine 6\d. 

 per ton of ore milled. 



DEVELOPMENT AND MINING COSTS. 



Sinking. — The cost of sinking main shafts varies according to 

 the size of the excavation, the hardness and breaking character of the 

 ground, the amount of water met with, the rate of progress made, 

 and many other factors. The rate of progress is very slow at Kolar ; 

 and there is little doubt that if the contracts for sinking were in the 

 hands of expert shaft-sinkers like the Americans who have made 

 such wonderful records on the Witwatersrand in South Africa, the 

 cost per foot could be reduced very materially. The following are 

 instructive examples of the cost of shaft-sinking at Kolar : — 



1. Vertical Shaft, Nundydroog Mine. — Dimensions, within tim- 

 bers, 12 x 6 feet. Depth at beginning of June 1900, 800 feet. Average 

 rate of progress since the commencement of sinking, 15 feet per 



