CENTEAL AND EASTEEN NEVADA. 387 



essentially from that already described in this chapter, employed at the Man- 

 hattan mill, in Austin, and need not be repeated here. The following notes 

 concerning this department will suffice. 



The mill is furnished with a Blake's rock-breaker. The stamps, 20 in 

 number, weigh 800 pounds each; they drop 9 inches, 70 times per minute. 

 Screens of wire-cloth, having 60 meshes to the linear inch, are used, the dis- 

 charge being on both sides of the battery. The capacity of the stamps is 20 

 tons per day. The roasting furnaces are the same, in all essential points, as 

 those in use at Ball's mill, in Washoe, described elsewhere. The amalgama- 

 tion of the roasted ore is performed in pans, as at the Manhattan mill. The 

 bullion produced is between 700 and 800 fine, the impurity being chiefly cop- 

 per. The average yield of the ore during the year 1867 was $111. The ore 

 assays from $130 to $150; of which value 80 or 85 per cent, is obtained in 

 the mill. Pan-tailings assay from $12 to $14 per ton. 



The machinery is driven by an engine of which the cylinder is 18 inches 

 in diameter and 36 inches stroke ; for which steam is furnished by two tubu- 

 lar boilers, 15 feet long, consuming about 6 cords of wood per day. 



The ordinary costs of reduction of the ore during 1867, for 3,847^ 



tons were $35 36 



And for repairs, per ton 5 19 



Equal to 40 55 



Of which the details are given below. 



The following statements show the working expenses of this mine for the 

 year 1867, including mining, milling, and general costs for the whole business. 



