Macfarlane on the Acton Copper Mine, 449 



of sliale b having been previously taken down) in the south- 

 westerly half of the opening, along a distance of about sixty feet 

 and to an additional depth of seven feet.* The limestone was more, 

 or less charged with ore along the whole of this distance; but hav- 

 ing in view the disadvantages which attend such large excavations 

 in depth, it was resolved to sink a shaft, in order to examine the 



Section along the line a — h of the general plan. 



S.E. 



A, Hill limestone ; B, underlying shale ; C, cupriterous limestone ; 

 D, hanging shale. 



ground before hand. Accordingly shaft No. 4 was commenced 

 in the south-west end of the working, and sunk, at intervals, to a 

 depth of seventy-five feet on the inclination of the bed. The first 

 twenty-five feet sunk below the open working was in rock con- 

 taining very good ore, of which rock eighteen and a half cubic 

 fathoms were excavated, and yielded — 



If 3 5 2 t^°s of first quality ore of 24.0 per cent of copper. 

 133|i " crush " 2.0 " « 



These quantities correspond, after deducting the loss in dress- 

 ing the crush ore (one-third of the copper contents), to 18.6 

 tons of 12 per cent ore, or about one ton per cubic fathom. The 

 co.st of sinking these twenty-five feet, and bringing the rock to the 

 surface, amounted to 8482.94 ; or to 826.10 per cubic fathom of 

 rock, and 825.96 per ton of 12 per cent ore. Below the twenty- 

 five feet the ground was poor ; and in June, 1862, the sinking was 

 discontinued, in order to the stoping of the ore ground on each 

 side of the shaft. Up to the end of July, 45.62 cubic fathoms 



• It is to be remarked with regard to this and other sections in this 

 paper, that unless when otherwise mentioned, they are not drawn to a 

 scale, and are merely intended to give an idea of the succession of the 

 rarious rocks, without reference to their thickness. 



Can. Nat. 29 Vol. VII, 



