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THE DIAMOND PROSPECTING CORE DRILL. 

 Bt STEPHEN ROGERS, F.G.S. 



One of the most important considerations in the development 

 of mineral property is the preliminary " prospecting," by which 

 the exact position, extent, thickness, and value of the mineral 

 deposits are determined. For this purpose the " Diamond Rock 

 Drill " is now being extensively used, both at home and abroad, 

 and the superiority of this method over that of the ordinary shaft 

 sinking is very striking. It bores a perfectly straight, smooth 

 hole to any depth, or in any given direction from the vertical to 

 the horizontal, bringing to the surface in order a solid section or 

 "core" of every stratum passed through, shewing its exact 

 depth, thickness, and the character of the rock. The " core " is 

 large enough to be thoroughly tested, and can therefore be 

 subjected to physical and chemical tests. Another advantage of 

 great value is, that, in the event of the mineral sought for being 

 absent, this important fact is conclusively proved. It also gives 

 positive information of the nature of the strata, thus making it 

 possible to estimate the cost of the shaft closely. Any machine 

 for accomplishing such work must have many requirements. It 

 must be strong, simple, and durable, economical in the use of 

 steam, and in the wear and tear of the diamond or " carbon " 

 points, rapid in operation, and, above all, its work must be 

 accurate and reliable. 



Many excellent diamond rock borers are manufactured, but 

 the " Sullivan " machine is the one I more particularly advocate, 

 as it combines all these important and essential features. As 

 regards its construction, with the exception of the smaller sizes, it 

 consists of the engines, the hoisting, and the feed apparatus. Each 

 part is distinct, and can be operated independently of the others. 

 They are mounted on a cast-iron base plate, which rests on a 

 bolted and braced hard-wood frame. The base plate slides 

 backvrards and forwards on ways on the frame, moved by a hand 

 lever working in a rack on the frame. The engines are designed 



