Byline: DAVID BANCROFT firstname.lastname@example.org
THE prospect of coal-seam gas mining in the Clarence Valley has sparked fears of environmental degradation, intrusion into property rights and loss of prime agricultural land.
We asked the Australian Science Media Centre if it could provide us with information not coloured by vested interests and it provided us with a briefing by Gas Industry Social and Environmental Research Alliance director Dr Peter Stone, University of Newcastle coal geologist and sedimentary petrologist Dr Judy Bailey and CSIRO petroleum and geothermal portfolio director Dr Edson Nakagawa.
Perhaps the most common phrase associated with coal-seam gas mining is fracking, and Dr Nakagawa said it involved injecting fluid comprised of water, sand and additives under high pressure into a cased well.
aThe pressure caused by an injection typically creates fracturing in the coal seam that can extend to a distance of two to 300 metres from the well,a he said.
aThe fractures grow slowly, for example an average velocity may be 10 metres per minute initially and slowing to less than one metre per minute at the end of the treatment.
aThe fracture treatments are designed to grow only in the zone of rock that contains a coal seam. The last part of the fracture treatment involves adding a propent, usually quartz sand into the fluid which
is carried into the fracture and props the fracture open so that the water and gas can be produced back to the well.a
He said the fracking fluid was comprised most of water and sand (97-97. …