RESPONDING to community concerns arising from the recent coal seam gas (CSG) forum in Forster, AGL has referred to their past record and future monitoring in Gloucester.
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“AGL has already drilled and hydraulically fractured 12 wells across the Gloucester Basin with no adverse environmental impacts,” said a spokesperson for AGL.
The corporate energy giant was not present at the recent CSG forum held in Forster recently but says it understands the community concerns around water during the coal seam gas production process.
“There are few things more precious on this continent than water supplies,” stated Mike Moraza, the Group’s general manager in a letter to the Great Lakes Advocate.
AGL asserts that it is doing all it can to ensure the region’s water tables are not compromised. Staff hydrogeologists conduct regular and comprehensive monitoring of more than 45 water bores in the Gloucester basin, and have baseline data for surface water, groundwater, and methane in air concentrations against which they measure future results. The Waukivory monitoring site, consisting of four wells on the verge of being fracked, features continuous water monitoring and flow testing, in preparation for the already approved Stage 1 (110 wells) of the project.
In response to concerns about aquifer contamination, AGL said it is targeting coal seams below shallow aquifers which are separated by numerous layers of rock. Drilling is performed in accordance with international and Australian standards, and they refer to each well’s concrete and steel lining sealing off the risk of cross-contamination “in accordance with the expected life of the equipment and environmental conditions”. How long that might be remained unanswered.
AGL acknowledges that water found within the coal seams has a higher concentration of heavy metals than water closer to the surface, but it says that the amount of elements like arsenic, cadmium, lead, and mercury is very small and typically well below the levels recommended by Australian drinking water and freshwater ecosystem guidelines.
As for Gloucester’s floodplain, a spokesperson for AGL said that there are no holding ponds for extracted coal seam gas water on the floodplain for either the Waukivory Pilot or AGL’s Stage 1 (110 wells). Gas wells on the floodplain can be shut down and sealed as required. Details for further stages were not provided.
Ponds elsewhere will be double lined with polyethylene, which AGL says is a high strength material resistant to salty water, and will only contain ‘produce water’ - the water emerging from the coal seams after the initial fracking solution has re-emerged. Should a leak be detected, water can be drained to other ponds and the leak repaired with the appropriate ‘heat welded’ patches.
As for the water extracted from the Waukivory pilot wells, it will be stored in a 1.5 megalitre tank that will be 2.3m high and made of galvanized steel. The ‘flowback water’ (the gas well’s first flush containing the fracking solution) will be trucked offsite to a licensed water recycling facility.
The subsequent ‘produced’ water will be pumped to the double lined holding pond on a nearby AGL property.
Monitoring and testing aside, those against CSG say that once the damage is done, it cannot be undone. MidCoast Water, whilst stating that the risk of contamination to shallower aquifers in Gloucester is remote, also acknowledges that it is difficult to reverse damage to water tables once it is done. Their focus is on assessing the potential of the damage before the full scale activity is underway.
In an industry surrounded by so much debate, one thing is certain – there are no guarantees. Whilst AGL emphasises their monitoring and safety systems, they did not respond to the question about what could be done to rectify any damage underground should it emerge.
It is estimated the Gloucester Gas Project, once fully operational, will cost AGL up to $310 million. Based on the data, the AGL Board will make a final investment decision in mid-2015.