METHOD AND APPARATUS FOR CHARGING A HOLE

摘要

A method of charging hole (12) drilled in rock or concrete (10), the method including inserting a quantity of energetic material (14) on or near the bottom (16) of hole (12). Lead (28) connects initiator (18) with an initiation source at ground level. Hole (12) is filled with stemming material (20) to a level (L) and plug (22) is positioned to rest on stemming material (20). Lead (28) threads through plug (22) via a slot, recess or passage. Mass (30) such as the bucket of excavator (32) and plug (22) prevent stemming material (20) from being blown out of hole (12) when energetic material (14) is detonated. The risk of collar area (C) being fragmented and energised to produce fly rock is reduced since the length of plug (22) is commensurate with the length of collar area (C). Plug (22) and stemming material (20) can be replaced by a stemming bar, with the stemming bar attached directly to energetic material (14).