36 HATCH : THE KOLAR GOLD-FIELD. 



cotton belting. The speed at which they are run varies from 50 to 

 75 revolutions per minute. To run the new 120-head Mysore mill, 

 crushing 10,000 tons of ore per month, to pass 1,600 screening, there 

 are two such engines each supplying power to 60 stamps. They are 

 run at a speed of 65 revolutions per minute, and the two engines 

 together indicate 340 horse-power with a boiler pressure of 80 lbs. 

 The consumption of coal (Indian) is 4*7 lbs. per indicated horse- 

 power per hour, the monthly consumption of coal being 500 tons. 



HOISTING ENGINES. — Both direct-acting and geared engines are 

 in use on the field. In all there are 56 winding engines having an 

 aggregate indicated horse-power of 1,979. Hoisting is by round 

 wire ropes of 1 to i|-inch diameter. Only in one case (at the 

 Nundydroog Mine) is a flat rope employed. The engines are of Sandy- 

 croft make. The following are examples :— The cage-engine at 

 Ribblesdale shaft (Mysore Mine) has 20-inch twin cylinders with a 

 4-foot stroke and is direct-acting; the skip-engine has 1 8-inch cylin- 

 ders and is geared to 12-foot drums. At the new vertical shaft, 

 Champion Reef Mine, the cage-engine is direct-acting and of the 

 horizontal girder type, with 20-inch twin cylinders, 4-foot stroke and 

 two io-foot drums. The skip-engine is geared at 5 to 1 and is of the 

 horizontal type with 20-inch twin cylinders and a 3-foot stroke. It 

 is geared to double drums of 12 feet diameter. 



At those shafts where a special compartment is reserved for 

 lowering timber, etc., there is a capstan-engine fitted to work single 

 or double purchase, and capable of handling up to 25 tons. 



Pumping Engines. — The engines in use on the Kolar gold- 

 field for running Cornish pumps are 26 in number, having an 

 aggregate indicated horse-power of 847. They are either single or 

 compound cylinder and condensing engines. If compound, the 

 arrangement of the cylinders is either tandem or twin. They are 

 always geared down and are connected with the pump-rods by sweep- 

 rods, the horizontal motion of the latter being converted to a vertical 

 or inclined motion corresponding to the angle of the shaft by angle 

 bobs. The weight of the pump-rods is also balanced at the surface 

 by a balance bob fixed at the end of the horizontal arm Tne sweep- 



