26 R. J. CHAPMAN ()N THE WALLBRIDGE HI-';MATITE MINE. 



have shewn that, lioth here and in the main pit, the ore is practically exhausted. No. 6, in 

 the annexed sketch-plan, indicates the position of a shaft sunk on this supposed extension 

 to a depth of nearly seventy feet. Drifts v^'ere run in an easterly and westerly direction, 

 to a distance of about twenty feet from the bottom of the shaft. These workings were 

 known as the Miller Mine ; but in one drift little more than poor, fragmentary ore and 

 iron-stained rock was met with, and in the other the indications were not suihcieut to 

 warrant further outlay. No. 7 shews the position of another shaft, sunk (against advice) 

 to about the same depth of seventy feet, immediately north of the Wallbridge pit, on the 

 thirteenth lot of the fifth concession. This passed through some light-grey crystalline 

 limestone and then entered the underlying guessic strata, meeting only wàth a small 

 string of hematite, and with little more than traces of amphibolic rock. 



A sample of ore taken some time ago from the body of the Wallbridge pit, contained 

 by my analysis 97.18 per cent, ferric oxide, equivalent to 68 per cent, metal, with only 

 2.78 per cent, amphibolic rock-matter ; whilst the best sample that I could get from the 

 bottom of the Miller shaft ' contained 23.43 per cent, rock-matter with much free silica 

 in it, and a second sample held no less than 29.32 per cent, rock-matter. 



As the working of all stock-formed deposits must necessarily be followed sooner or 

 later by the exhaustion of the ore, and as no surfiice indications will enable one to predict 

 with any certainty the amount of ore present in a stock-formed mass, greater caution than 

 usual is recjuired in handling these deposits. Happily, in the diamond drill, we have the 

 means of testing rapidly and economically the dimensions and general purity of ore-masses 

 of this character. By a few borings put down at short distances beyond the visible or 

 sixpposed limits of the deposit, and in the central part of the deposit itself, not only can its 

 dimensions be safely ascertained, but the cores of ore brought up by the drill will afford a 

 thorough insight into the character of the deposit, from depth to depth, throughout its 

 entire mass. 



' Al, tlie il.nle of my vi.sif, to lliis sn-rallod mine, llio di-ifts Merc cntiiv.ly rld.sod, so (lia(- T (■(jiilil not. jrol into 

 llieni. 



