TREATMENT OF THE COMSTOCK ORES. 239 



tlement. This cannot be accomplished without some trouble and expense, a 

 large number of assays being necessary in order to obtain a reliable average 

 result. For this purpose the Savage Mining Company follow a very carefid 

 system, and have assays made of a double set of samples of every lot of ore. 

 One set of these samples is taken from the wagon, taking the ore from the mine 

 to the mill, the other is taken from the mill after the ore has been crushed. 



The wagon sample is obtained by drawing from every wagon load of ore 

 dispatched to any mill a sample of the rock, keeping distinctly separated from 

 each other the samples of the ore sent to different mills. Each of these sam- 

 ples is assayed, or, sometimes, a number of samples of loads that were all 

 sent to the same mill during one day are mixed together and the assay taken 

 from the mixture. The mill is then charged daily with the weight of ore and 

 the amount of gold and silver represented by the assay. 



The mill sample, which is to serve as a check on the wagon sample, is 

 usually taken by allowing the crushed ore as it comes from the battery to run 

 into a pail or other suitable vessel, which is held or placed at the end of the trough 

 or apron leading from the batteries to the tanks. A sample is taken in most 

 mills every hour, in some more frequently, and the accumulated samples taken 

 during a single day are well mixed together and dried. From this mixture a 

 sufficient quantity is drawn for assay.^ Where there are several batteries 

 they may be selected alternately for sampling, or samples may be taken from 

 each battery separately. 



1 The Savage Mining Company have an assay department for the purj)ose of 

 assaying ores and bullion. The following statements, taken from this company's last 

 annual report, furnish an interesting exhibit of the extent of this business, the kind 

 and quantity of materials consumed, and the average cost of assays : 



Assay department, for Ore, from October 5, 1868, to July 1, 1869. 



Materials consumed. EXPENSE. Cost value. 



Crucibles, 554 $98 43 



Crucible covers, 640 87 50 



Muffles, 3 3 00 



Charcoal, 1,564 bushels 544 16 



Acid, nitric, 59 pounds 31 38 



Bi-carbonate of soda, 329 pounds 35 31 



Bone ash, 196 pounds 36 70 



Litharge, 350 pounds 53 00 



Salt, 400 pounds 21 75 



Granulated lead, 4 pounds 1 50 



Mattrasses, 6 1 50 



Clay melting furnace, 1 25 00 



Cupel rack, 1 5 00 



Iron pans, 12 fi 00 



