METHOD AND APPARATUS FOR PREVENTING ROCK FRAGMENTS FROM ENTERING OR COLLAPSING INTO A BLAST HOLE

摘要

The invention provides an apparatus and method for preventing surrounding loose rock fragments from falling or collapsing into a blast hole. The apparatus includes a flexible sheet including a pair of spaced apart longitudinally extending side edges and a pair of spaced apart laterally extending end edges. The sheet has a curved form defining a longitudinal passage extending between openings at longitudinally opposite ends, one end of the curved sheet being insertable into the open end of a blast hole whereby the curved sheet closely faces an internal surface of the blast hole and forms a barrier preventing surrounding loose rock fragments from falling or collapsing into the open end of the blast hole. The invention also provides a bench blasting method and a deployment device for deploying the apparatus into a blast hole.