56 



DEEP BOREHOLE SURVEYS AND PROBLEMS 



the width of the hole, and diamond drilhng with its small 

 holes later on made it obsolete. A similar method was also 

 applied by the engineer Zobel in Schonebeck in 1855.^ 



Lubisch's Method. — The boring master Lubisch improv- 

 ed on Kind's method in the Upper Silesian mineral fields 

 in 1887. He diamond drilled a core first without a core 

 catcher, leaving the stub standing in the hole. Then he 

 lowered a second tube (Fig. 28) over the stub and marked 

 it in a definite manner respecting the meridian and later 

 extracted it, orientating it as in Kind's method. It 

 suited small holes better. In Fig. 29 the steel tooth of the 

 orientating tube closes about the core and makes a definite 



Figs. 



28 AND 29. — Lubisch's core 

 marker. 



^^. 



Fig. 30. — Vivian's pilot-hole core 

 compass. 



mark which was expected to have a definite known surface 

 orientation. After lifting out this marker device a core 

 extractor was let down to bring out the scribed core. Now 

 the scribed longitudinal mark is adjusted to the vertical 

 plane by means of a spring pen hanging on the rods and the 

 dip and strike read. Lubisch improved his apparatus 

 later by adding a cap carrying a steel scriber which gave a 

 mark at right angles to the side mark, and he also improved 

 the joints to prevent twisting on insertion and extraction. 

 Lubisch's advantage over Kind was in the more rigid 

 hollow rods and the possibility of working in smaller bore- 

 holes. For success the following demands, difficult and 

 nearly impossible to attain altogether in practice, are to be 

 fulfilled: 



1 Mitt. Markscheiderwesen, Heft 4, p. 37, 1902. 



