Hydraulic fracturing has been used by the mining industry at least since the end of the 19th century, when it was applied to quarrying blocks of granite, and in the petroleum industry since the late 1940s when it was introduced to stimulate wells. It now represents a major petroleum service industry and is used widely to stimulate oil, gas and coal seam methane wells. Recently, hydraulic fracturing has been used, again in mining, to precondition rock for caving and for stimulation of horizontal in-seam gas drainage holes.
Work at Dartbrook coal mine in 2002 by CSIRO demonstrated the significant benefit that fracturing of in-seam drain holes can have on gas drainage rates. Placing small sand-propped hydraulic fractures along in-seam holes, especially in low-permeability coal zones, was shown to produce stimulated gas flow that was 20 to more than 100 times the un-stimulated rate. CSIRO and SCT Operations continue to work in this area to develop reliable methods to stimulate drain holes in conditions that preclude use of open-hole straddle packer systems. (Rob Jeffrey,CSIRO Petroleum)