Heat on gas mining
Concerns about the future of WA water supplies are being raised as mining companies embark on the controversial extraction of gas deposits.
Hydraulic fracturing, or ‘fraccing’, is being carried out aimed at sourcing the State’s future energy supplies.
Australian miner Transerv this week stepped up gas exploration in the Warro region, 60km east of Jurien Bay.
AWE is drilling at the Irwin River region, 15km east of Dongara, and the Woodada deposit, 10km west of Eneabba, with fraccing expected later this year.
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Norwest Energy is targeting the Arrowsmith gas field, 30km north of Eneabba, which will be fracced in the September quarter.
Exploration licences for unconventional gas have been granted for Wellington Dam near Bunbury, Kaloorup Road near Busselton and the Kimberley’s Canning Basin.
Fraccing involves pumping fluids to create fissures in natural rock formations to allow natural gas to move more freely in wells. The process has been banned in parts of Europe and the US, after it led to contamination of local water supplies.
New South Wales imposed a moratorium on fraccing to allow for a Senate inquiry to be conducted into coal seam gas mining.
Chemicals used in fraccing were found to cause cancer and damage unborn babies, according to a group of Queensland medical experts.
Benzene, toluene, ethylbenzene and xylene, or ‘BTEX’, chemicals are commonly used to extract natural gas and are linked to human health risks.
Fraccing is used to extract unconventional gas deposits, which include coal seam gas, tight gas or shale gas.
Underground reservoirs around Dongara, Eneabba and Gingin contain tight and shale gas.
State Mines and Petroleum Minister Norman Moore said WA’s situation differed greatly from the eastern states.
“WA’s geology is significantly different from that of Queensland and NSW, which means unconventional gas is less likely to occur in similar situations than it does in those states, ” he said.
“WA’s unconventional gas resources are located at significantly greater depths — between 2000m and 3000m — separating it from potable water aquifers which are usually located at less than 500m.
“Regulators have powers to implement conditions or request more information, surveys and programs to manage risks if any hydraulic fracturing was proposed.”
Department of Mines and Petroleum (DMP) director of petroleum Bill Tinapple said more than 20 licences were granted to tap underground gas reserves in the Mid West.
These reserves lie below confined and unconfined aquifers in the Arrowsmith groundwater area.
Mr Tinapple assured measures were in place to prevent the contamination of these aquifers.
“The nature of shale and tight gas reservoirs formation prevent gas migration into the water table, ” he said.
“Well designs and drilling programs are thoroughly assessed to assure integrity and no uncontrolled flow of fluids.”
Mr Tinapple cited cement casing of fresh water aquifers as one of the measures to ensure groundwater integrity where fraccing takes place.
Mining companies are required to divulge extraction methods, including chemicals used, to the DMP when they intend to extract underground gas. The information is withheld from the public for commercial reasons.
WA Greens MLC Alison Xamon called on the State Government to release more information about hydraulic fracturing.
“The public cannot be assured the chemicals being used are not toxic, as has been the case in fraccing around the world, unless there is full transparency in what is being pumped into the ground, ” she said.
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