1864.] 473 ILesley. 



right rises so fist as to overrun the timbers of the old tunnel (See Fig. 

 2) which is driven into the face of the quarry at a level 20 or 30 

 feet higher than c. Another gallery has.a shaft 30 feet deep at its 

 end. The whole mine is in fact nothing but an extensive shaft 

 exploration, leaving the mass of the ore untouched. We have, there- 

 fore, data in sight for the following calculation : 



Quant it}/ of Ore in the Mine, in Siijht. 



Galleries one way, 200 + feet = 70 yards, ] 



Galleries the other way, 150 feet = 50 yards, \ say 60,000 cubic yards. 



Average height above tunnel, 50 + feet = 17 yards, J 



Add length of quarry, 150 + 150 feet = 100 yards, 1 



Take same breadth as above (200) = 70 yards, \ say 175,000 cubic yards. 



Depth of shaft in quarry, (70 +) = 25 yards, J 

 To which add for quarry slopes, Ac, say 15,000 cubic yards. 



Total in sight of the Home-bank, say 250,000 eubic yards. 



This does not take into account the existence of ore to a greater 

 depth than the bottom of the shaft, 70 feet, where, as the miners 

 assert, they stopped in solid ore; and there is no reason to doubt 

 the fact, seeing 1, that the 30-foot shaft, at the inner end of the side 

 gallery, left oif in ore, and the dip would carry it far below the 

 bottom of the 70-foot shaft ; and, 2, the bottom of the 70-foot shaft 

 is still 70 feet above the creek at the furnace, and therefore within 

 the limits of underground drainage and decomposition. It is also 

 left out of sight, in the above calculation, that the ore passes outward 

 and downward from the quarry in the direction of x, (Fig. 3), all of 

 which must be added to the sum total above. 



Thus, a surface section of the ore belt 50 yards long represents 

 ore beneath it to the e:itent of, say 250,000 cubic yards. 



The mining done in past years from this bank half way to the 

 furnace, and the exhibitions of ore at the surface at the furnace, 

 warrant us in using the above calculation for that distance, viz., 2200 

 feet, or say 700 yards, = 3,500,000 cubic yards of ore in the ground. 



Openings made, also, at intervals, beyond the Home-bank, to a 

 distance of a mile and a quarter from the furnace, will, on the above 

 calculation, increase this quantity to 11,000,000 cubic yards of ore 

 in the ground. There is no reason for doubting that the ore belt con- 

 tinues equally rich to a greater distance northward, along the face of 

 the mountain, past the White Rock Gap, and towards the Coneco- 

 cheague, at Caledonia Iron Works. But as the surface exposures can 

 never be implicitly relied on, and as the quantity of ore depends more 

 upon the local depth of drainage and decomposition than upon any 



VOL. IX. — 3l 



