GOLD MINING IN OOLOEADO. 517 



The following data, however, furnished by the superintendent, Mr. Congdon, 

 from the company's books, and reliable so far as they go, give some general 

 results. 



During 1867 the j)roduct of the mine was 12,193|- ounces of crude bull- 

 ion, yielding in currency $279,647 76, or $22 81 per ounce. The number of 

 cords or tons from which this product was obtained is not stated, but the yield 

 of the rock at that time is said to have been 10 ounces of bullion to the cord. 

 Assuming this to be correct, the quantity worked would have been 1,220 cords, 

 which, at a trifle more than eight tons to the cord, would be equal to 10,000 

 tons. On this basis the yield of the rock would have been $27 96 per ton, 

 in currency, or $20 11, in coin, allowing the average value of the ounce of 

 amalgam to be $16 50. The yield of 10 ounces of bullion to the cord is much 

 higher than that now obtained, and is perhaps overstated. Another method 

 of arriving at the quantity is by considering the average amount treated 

 weekly, which is stated at about 32 cords. This in fifty weeks would amount 

 to 1,600 cords ; and allowing seven and a half tons to the cord, which is, per- 

 haps, more nearly correct than eight tons, we have a total of 12,000 tons of 

 ore, of which the yield per ton would be $23 30, in currency. 



During this period the costs were as follows : 



Mining expense $137,214 65 



Milling expense 39, 998 02 



Teaming expense 17, 212 96 



194,425 63 



If the quantity of ore produced was 12,000 tons, the cost of mining was 

 $11 43 ; of milling, $3 33 ; of teaming, $1 44 ; and of all the foregoing 

 together, $16 20 per ton, in currency. 



The total product being $279,647 76 



And the above named costs 194, 425 63 



The excess of yield over costs was 85, 222 13 



