Macfarlane on the Acton Copper Mine, 457 



sequently, a cubic fathom of this rock yielded 2.Y6 tons of 12 

 per cent ore. The total expense of niining and hauling to surface 

 was 8l'777.12, or $9.68 per cubic fathom, and 83.50 per ton of 12 

 per cent ore. The width of the limestone horizontally across 

 "Williams's pit, at this point, is 150 feet; the width of the stope 

 nine fathoms. If we assume the thickness of the limestone, at 

 right angles to the underlying shale, to be twelve fathoms, which is 

 evidently a moderate estimate, then a square fathom, along the 

 plane of the bed at this point, contains 33.12 tons of 12 per cent 

 ore. In the upper part of Williams's pit, the conglomerate charac- 

 ter of the cupriferous limestone, referred to in describing No. 5 

 shaft, is beautifully developed. Masses of this character have fre- 

 quently been blasted out, measuring at least eight cubic yards. A 

 large mass of nearly the same dimensions was found loose on 

 the surface of this deposit. On drilling a hole into it, preparatory 

 to blasting it, the borings obtained were carefully collected and 

 examined. They contained : 



Silica, 36.98 



Carbonate of lime, 4.64 



Alumina, 0.84 



Iron, 7.01 



Copper, 34.20 by assay. 



Sulphur, 16.33 by difference. 



100.00 



The three last ingredients calculated to 100 parts give 



Iron, 12.18 



Copper, 59.44 



Sulphur, 28.38 



100.00 



which figures approximate pretty closely to some analyses of pur- 

 ple copper. In the bottom of Williams's pit, about forty feet below 

 where this mass was found, the ore is more solid, not so much 

 diffused through the limestone, but concentrated in veins, which 

 are pretty distinctly separated from the side rock. In one of 

 these, of considerable thickness, I found the purest purple copper 

 which I have yet observed on the mine. It contained neither 

 lime nor silica, and assayed 61.9 per cent of copper. At no great ^ 



