Drilling technique could save coal miners money

A drilling technique for coal mining using methane extraction technology has been developed by the Cooperative Research Centre (CMTE) in collaboration with BHP Mitsui Coal. Both are based in Brisbane, Australia.

The technique, known as tight-radius drilling, will be developed and brought to market by CMTE.

The technology enables coal to be drained of highly explosive methane gas in advance of mining, thus eliminating the need for underground crews at this stage. The technology could save coal miners millions of dollars.

The system is lowered into a vertical well to the depth of a coal seam, where a specially engineered water jet, which acts as a cutting device, drills laterally into the coal. The mechanism can drill in any direction, creating as many holes as is necessary, and can be lowered or raised to work in multiple seams.

The drill holes increase the permeability of the seam, allowing methane to find its way to the surface, once the water used by the drill is pumped out.

The system has been tested in field trials throughout Australia, and CMTE industry partner Anglo Coal has already begun using tight-radius drilling to drain methane from seams it intends to mine.

“The technology is being prepared to meet commercial demand, [and there are] plans to mount the system on a purpose-built truck to allow rapid mobilization from one vertical well to the next,” says Michael Hood, chief executive officer of CMTE.