Concentrates,32,929 short tons = 76·08 per cent. of charge.
Fine sulphide ores,9,590" = 22·16""
Limestone,762" = 1·76""
Total charge,43,281" = 100·00""
Weight of “calcines” produced, 35,533" = 82·10""
Shrinkage,7,748" = 17·90""
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The total costs of roasting (from roaster charge-bins to reverberatory furnace) worked out at 38·45 cents per ton, the distribution of these costs being as follows:—

Total Costs. Cost per Dry Ton.
Sampling,$ 222·62   $ 0·0051
Bedding,2,016·27   0·0466
Reclaiming,3,072·71   0·0710
Operating furnaces,7,680·58   0·1775
Hauling calcines,911·01   0·0210
General expenses,1,639·99   0·0379
Total direct costs,$ 15,543·38   $ 0·3591
Cost of flux,1,097·85   0·0254
 Total costs,$ 16,641·23   $ 0·3845
════════   ════════
Analysis of Cost—
(1) Operating—  
Labour,$ 7,398·56   $ 0·1709
Power,1,577·64   0·0365
Fuel,773·08   0·0179
Water,78·71   0·0018
Sundries,10·30   0·0002
Flux,1,097·85   0·0254
$ 10,936·14   $ 0·2527
(2) Repairs—$ 2,507·35 $ 0·0579
Labour,  
Shop expense,361·00   0·0083
Supplies, 2,836·74   0·0656
 Total costs,$ 16,641·23   $ 0·3845
════════   ════════

References.

Peters, E. D., “Principles” and “Practice of Modern Copper Smelting.”

Cloud, T. C., “The M‘Murty-Rogers Process for Desulphurising Copper Ores.” Trans. Inst. Min. and Met., vol. xvi., 1906–7, p. 311.

Hofman, H. O., “Recent Progress in Blast Roasting.” Bulletin Amer. Inst. Min. Eng., No. 42, June, 1910.

Austin, L. S., “The Washoe Plant of the Anaconda Copper Mining Company.” Trans. Amer. Inst. Min. Eng., vol. xxxviii., 1906, p. 560.

Rickets, L. D., “Developments in Cananea Practice.” Engineering and Mining Journal, Oct. 7th, 1911, p. 693.

Redick F. Moore, “Recent Reverberatory Smelting Practice.” Engineering and Mining Journal, May 14th, 1910, p. 1021.