Hydraulic Fracturing Applied to Inducing Longwall Coal Mine Goaf Falls Available to Purchase

ABSTRACT: This paper describes the first successful use of hydraulic fracturing to induce a goaf event and control the timing of caving events in Australia. Hydraulic fractures are initiated at 7 to 10 m above the bottom of a thick conglomerate roof and, because of the low vertical stress magnitude relative to the other two principal stresses, grow as horizontal fractures. The fractures extend radially outward from the injection borehole into the rock until a goaf fall occurs. Hydraulic fracturing has provided a means to control the timing of wind blast events and thereby significantly improve safety. The successful implementation of hydraulic fracturing at Moonee Colliery to control the timing of goaf events has enabled the mine to continue operating.