Describe with sketches the method of supporting weak shale roof.

METHOD OF SUPPORTING WEAK SHALE ROOF                 When shale roof can be supported by special type of roof stitching recently designed by CMRI, Dhanbad.Two holes 1.5m deep shall be drilled on two sides at the roof level at an angel of 45° using ordinary coal drills.Three more holes of the same depth shall be drilled vertically in the roof at equal intervals in the same alignment.A piece of old haulage rope 20-22mm dia shall be cut with a length=depth of two holes+width of gallery.One end of the rope shall be fixed in one of the side holes with cement grout and a wooden plug shall be hammered to prevent the rope shall be fixed in corresponding inclined hole with the cement grout.Now there j-bolts shall be fixed with cement capsule and wooden plugs in the three vertical holes.While fixing j-bolts,there lower end shall be anchored to the rope.When cement is set, wooden sleepers shall be placed between two adjacent rope as laggings and they shall be tightened by hammering wooden wadges. j-bolts will strengthen the roof by clamping the roof rocks and the roof will prevent the roof strata from coming down by providing a support from below.

Mining Engineering

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Mining Engineering

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