CORE ORIENTATION 



55 



c. Lowering an instrument on to a freshly cut core and 

 then extracting it with or without the core. 



d. Photographic devices for the walls of the hole. 

 Kind's Method. — Kind's core drill is the earliest form 



known, having been employed in coal strata near Forbach 

 in Lorraine in 1844^ using a free-fall percussion drill 

 (Rotary core drilling was first adopted in 1861 by the French 

 engineer Leschot) . 



Kind also made the first core orientation. The method 

 has long been superseded and information thereon is 



rA^ 



^ 



Fig. 26. — Kind's borer. 



Fig. 27. — Kind's core breaker. 



scarce. It was employed in 1854 in Forbach yielding a 

 half-meter core which was brought to bank in as unaltered 

 a condition and position as possible. 



Figure 26 shows Kind's fork-shaped borer which provided 

 the thin core 12 to 20 in. long and was then extracted. A 

 core breaker a (Fig. 27) was lowered to tear off and lift 

 out the core b; this breaker had a toothed inner cylinder c 

 keeping the teeth d forced out during insertion and sus- 

 pended by a cord from the surface. To prevent turning 

 he employed two index arms held against the rods, one by 

 a man in the derrick near the top of the drill rod and the 

 other at the derrick floor. These arms aligned the pipe 

 against twist. The method yielded cores of only about half 



iRedmayne, R. a. S., "Modern Practice in Mining," Vol. 1, p. 91. 

 Macready, G. a., Bull. Amer. Assoc. Petroleum Geol., Vol. 14, 1930. 

 KoEBRiCH, A., Pr. Zeitschrift, Vol. 36, p. 256, 1888. 



