METALLURGICAL PRACTICE, 



53 



At the Champion Reef Mine the capacity of the plant is 9,000 

 tons. There are 18 wooden vats each having a capacity of 54 tons. 

 Of these 6 vats are reserved for the treatment of slimes (old ac- 

 cumulations from the Wheeler pans) the remainder being for mill- 

 tailings. The treatment lasts three days, 6 vats being rilled and 

 discharged every day, During the year ending 30th September 

 1899, 77,330 tons of mill-tailings were treated, producing 16,543 

 ounces of bullion, and 22,476 tons of slimes from the pan process, 

 The extraction of tailings averages 58*6 per cent. The strength 

 of the strong solution is 0*25 per cent ; the consumption of cyanide, 

 1-4 lbs. and of zinc, o"ilb. per ton treated. 



At the Ooregum Mine the capacity of the plant is 9,000 tons per 

 month. The percolators are open air masonry vats, measuring 55 

 by 25 feet with a depth of 5 feet. Hitherto the plant has only been 

 used for the treatment of slimes from the Wheeler pan process ; the 

 average extraction being 71 per cent. 



At the Nundydroog Mine there are nine percolators, vis*, three 

 steel vats of 25 feet diameter by 4 feet 6 inches deep and six wooden 

 vats of diameter 21 feet by 4 feet 9 inches deep. The treatment is 

 similar to that of the other mines. During the year 1899, 46,047 

 tons of tailings were treated, yielding 5,163 ounces of bullion or an 

 average of 2 dwts. 6 grains per ton. 



With regard to working costs the following particulars for the 

 year 1899 have been compiled from statements published by three 

 of the leading companies : — 



Name of company. 



Quantity of 



tailings and 



slimes treated. 



Cost of 

 treatment. 



Cost of treatment 

 per ton. 



Mysore 



Champion Reef 

 Nundydroog 



Tons. 



81,558 

 99,806 

 46,047 



£ 

 13,264 

 17,089 



5.458 



■J. d. 

 3 3 

 3 5"5 

 2 4-4 



Costs were higher during 1899 than they are now, owing to a 

 scarcity of labour produced by plague scares. The Mysore plant for 



