Illustrated Mining Terms

J

Jackleg - A percussion drill used for drifting or stopping that is mounted on a telescopic leg which has an extension of about 2.5 m. The leg and machine are hinged so that the drill need not be in the same direction as the leg. jackleg.jpg (4134 bytes)
Job Safety Analysis (J.S.A.) - A job breakdown that gives a safe, efficient job procedure.  
Joint - A divisional plane or surface that divides a rock and along which there has been no visible movement parallel to the plane or surface. Marly Freshwater Member at Stair Hole

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