468 Macfarlane on the Acton Coj^fper Mine. 



the months of July, August and September, 1862, there were 

 crushed 3,348,887 lbs. of crush ore and smalls, of from 2.0 to 5.9 

 per cent, averaging 4.1, and containing in all 13*7,969 lbs. of cop- 

 per. From this there were produced 1,073,644 lbs. of products 

 of from 8.0 to 12.6 per cent., averaging 9.9 per cent, and con- 

 taining 106,625 lbs. of copper. There were consequently cast 

 aside 2,275,243 lbs. of skimmings and slimes, averaging 1.38 per 

 cent, and containing 31,344 lbs. of copper; which is equal to 22.7 

 per cent of the copper contained in the original ore. 



From the results here narrated, it would appear that at least 

 one-fourth of the copper contained in the crush ore is lost in the 

 process of dressing it. The actual value thus wasted goes far to 

 counterbalance the saving of freight which results from concen- 

 trating the ore. It would not certainly be attended with greater 

 advantage to send the crush ore of four or five per cent to market 

 instead of dressing it ; but it admits of plain proof, that it would 

 be better at once to sell an ore of seven per cent, and pay freight 

 on it to Boston or New York, rather than to submit it to further 

 concentration by crushing and jigging, and sustain the great loss 

 of copper which occurs in these operations. The following calcu- 

 lations will be found to confirm this statement : 



100 tons of 7.0 per cent ore would bring in Boston 

 $4.00 per unit ; which for 6.5 per cent, (^ per cent 

 being deducted for the difference between dry and 

 humid assay) is equal to $26.00 per ton, $2600.00 



From this deduct freight, barrels, &c., at $9.00 per ton, $900.00 



There remains, $1700.00 



On the other hand, 100 tons of 7.0 per cent ore would 

 yield, by crushing and jigging, about 43f tons of 

 12.0 per cent products ; which would bring, say at 

 $4.30 per unit, for 11.5 per cent, $49.50 per ton,. . . $2163.43 

 From this deduct : 



Cost of crushing, &c., at $5.50 per ton, $240.70 



Freight and barrels, at $9.00 " 393.75 634.45 



There remains, $1528.98 



or $1.71 per ton less than when at otice sent to market. It is 

 thus evident that an advantageous concentration of a seven per 

 cent ore by means of crushing and jigging, is not possible. The 



