1 873.] Colorado Gold Mines, 25 



" gross receipts from rock of the first class are about 36*24 

 per cent, and from rock of the second class about 32*13 per 

 cent of their total assay value in gold, silver, and copper." 

 He classes the veins now worked under two heads, the first 

 yielding an average in gold, silver, and copper of 50*80 dols. ; 

 the second class an average of 30 dols. per ton. The first, 

 as he shows, returns a profit to the miner ; the second is 

 worked at a loss. 



Fifty tons of ore, whose contents in gold, silver, and copper 

 is worth, say 50 dols. per ton, but 'in gold, which alone is 

 saved, only 29*40 dols., will cost and yield as follows : — 



Dollars. 



5 tons, worth, say 100 dols., will bring 



from the smelters 60 dols. per ton . . 300*00 



Forty-five tons, treated in the mill, and worth in gold 29*40 

 dols. per ton, will yield as follows : — 



Dollars. 



40 per cent of 29*40 dols. per ton, the result 



of battery amalgamation 529*20 



4 per cent of 29*40 dols. per ton derived 

 from the blanketings when treated in 

 pans 52*92 



Concentrated tailings, 2*25 tonsati6*94 dols. 38*12 



920*24 

 Cost of Mining and Milling, 



Dollars. 



Mining and carting 50 tons at 6 dols. 



per ton 300*00 



Milling 45 tons at 3*84 dols. . . 172*90 

 Treating blanketings in pans 14J 



cents per ton 6*30 



Concentrating tailings 9*81 



489*01 



Gross profit 43 I# 23 



From this must be deducted cost of ad- 

 ministration, and tax of, say 18 cents 

 per ton, amounting to, say 1*26 dols. 

 per ton 63*09 



Nett profits 368*14 



Or, 7*36 dols. per ton. 



Veins of the second class containing 30 dols. in gold, silver, 

 and copper, but not over 21 dols. in gold alone, it is evident 

 vol. in. (n.s.) e 



