Radial points on proposed drill bit take advantage of natural fracture planes of coal. Radial fracture points retracted during drilling and impacted by piston to fracture coal once drilling halts. Group of bits attached to array of pneumatic drivers to fracture large areas of coal face.
Mechanical Coal-Face Fracturer
NASA Tech Briefs ; 8 , 1
1984-04-01
Miscellaneous
No indication
English
Online Contents | 1995
Roof Support Near Coal-Mining Face
NTRS | 1984
|Coal Loses Face in UK Energy Scene
British Library Online Contents | 1992
Accidents at coal face and their prevention
Engineering Index Backfile | 1936
|Coal-Face Fracture With A Two-Phase Liquid
NTRS | 1985
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