Macfarlane on the Acton Copper Mine, 467 



eight to eleven per cent, and is then in a marketable state. The 

 costs of these various dressing operations were as follows : — Coarse 

 spalling costs from fifteen to twenty-five cents per cubic yard of 

 rock, according as the same contains less or more ore ; fine 

 spalling from fifty to eighty cents per ton of the resulting ore, 

 according to the quality of the rock operated on. The processes 

 of crushing and jigging cost during January, February and 

 March, 1682, $5.60 per ton of products, and 81.15 per ton of 

 crush ore. The total expense of coarse and fine spalling, and 

 crushing and jigging, per ton, of all the products is at present 

 $5.25. 



The crushing and jigging processes are ulmost the same as 

 those adopted in Cornwall for the dressing of crush ore, ;^et 

 they are attended with the loss of much of the copper contained 

 in the original crush ore. Having for a long time estimated 

 the quantities, and assayed the samples of the crush ore put through 

 the rollers; and ascertained the weight and contents of the resul- 

 ting products, I have found that the loss of copper is much more 

 than might at first sight be imagined. I subjoin a few of the 

 results obtained: From the I'Zth of November to the 12th of 

 December, 1861, there were crushed 956,760 lbs. of ore, contain- 

 ing 4.6 per cent, or 44,010 lbs. copper. From this there were 

 produced 283,451 lbs. of products, averaging 10.95 per cent, and 

 containing 31,052 lbs. copper. There were consequently lost 

 673,309 lbs. of skimmings and slimes of 1.92 per cent, con- 

 taining 12,958 lbs. copper. Thus 29.5 per cent of the copper 

 contained in the crush ore was lost in the skimminofs and 

 slimes. Further, during January, February and March, 

 1862, there were crushed 2,881,100 lbs. of ore averaging 3.4 

 per cent, and containing 100,303 lbs. of copper; from which 

 there were roduced 615,520 lbs. of products averaging 9.5 per 

 cent, and containing 58,711 lbs. of copper. There were con- 

 sequently 2,265,580 lbs. of skimmings and slimes of 1.83 per cent* 

 containing 41,592 lbs. of copper. Thus 41.5 per cent, of the 

 copper contained in the crush ore was lost. It is to be remarked? 

 however, with regard to the foregoing results, that much of the 

 copper contained in these skimmings and slimes is with proper 

 appliances recoverable. Subsequent to the first of July, 1862, ar- 

 rangements were made for dressing the ore by contract, and for 

 working up a part of the slimes as these were being produced. 

 Under this system the following result was obtained : — During 



