1873.] 



1(35 



[Lesley. 



band of ore. Call it 6 feet, arid the 10 or 13 feet of measures to the 

 bottom of the lower band, as represented in the section taken north of 

 his house, and again in Dutch Corner, and we have a total depth of 17 

 fret. A length of b ink-face should be set out, limited only by boundary 

 lines, deviations in level, or quantity to be supplied, and this face should 

 be quarried in widths, strip after strip from end to end, advancing up 

 hill as rapidly as dictated by the demand, dumping the stripping and 

 quarried refuse upon the cleared out ground, far enough away not to 

 stifle the work to be done along the bank-face. 



Peeking the width of strip best adapted to the result aimed at, and 

 under certain conditions using gunpowder, the line of least resistance 

 will fix that width ; and as it is a heaving in mass that is contemplated, 

 and not a blowing to pieces, the shots would be put to the bottom of the 

 lowest band of ore. Eleven feet, then, would be the length of the line 

 of least resistance, and the width of strip taken at one time not less. 

 The sketch below, made from a section taken on "Walter's farm and 

 showing the three bauds of ore, will help to convey the intention. 

 Fig. 12. 



■. ^T&ziZ&zzm - ,-'• ■■■- - ~ - — . 





SKETCH OF BANK-FACE WITH THE STRIPPING OFF TO THE FIRST 8AND OF ORE . 



A. Face of stripping, 6 feet thick. 



B. Surface of Top Band Ore, 11 feet width of strip, 24 inches thick. 



C. Interval of Shales and Sandstone, 42 inches. 



D. Middle Band of Ore, 12 inches. 



E. Interval of Shales and Sandstones, 36 inches. 



F. Bottom Band of Ore, 13 inches. 



Depth of Ore face with 2 intervals, 10 feet 7 inches, include Stripping, 

 16 feet 7 inches. 



But as the ore to be taken out constitutes in bulk only a fourth of that 

 tj be quarried, and as when loose the refuse will occupy one and a half 



