There is mounting evidence that coal seam gas mining poses substantial risks to water.
CSG is trapped underground by water pressure. To mine the gas, this water must be drawn out of the coal seam to the surface. It is high in salt and methane, and can contain naturally occuring toxic and radioactive compounds and heavy metals.
Soil testing around CSG wells and wastewater ponds in the Pilliga forest in 2012 found arsenic, lead, chromium, salts and petrochemicals - only made public after local residents tipped off the EPA.
Desalinated CSG waste water released into the Condamine River contained boron, silver, chlorine, copper, cadmium cyanide, zinc and other toxic chemicals.
Hydraulic fracturing (fracking)
When using fracking — a CSG extraction method that involves pumping water, sand and chemicals into the ground to fracture coal and increase the flow of gas out of the well — contaminants escape into the surrounding environment. Only 20% to 80% of fracking fluids are recovered.
In May 2011, a fracking blow out occurred at AGL’s CSG well head at Camden North in NSW during routine maintenance. This incident released plumes of contaminated water and methane into the air in the vicinity of housing and a water catchment feeder stream. AGL failed to report the incident for two days until the leakage was shown on TV. In June 2011, there was a similar blow out at an Arrow Energy CSG well head near Dalby in Queensland. Methane and water spewed up to 90 metres in the air for two days before being capped.
CSG wells connect the surface to coal seams, and pass through any aquifers present. About 6-7% of unconventional gas wells fail and leak within a year of construction, and about 50% fail before being shut down. When a CSG project ends, the wells — built and plugged with concrete and steel that degrade — must last forever.
Take a look at this short documentary from the makers of ‘Gasland’ – revealing the US industry’s own admissions on well failure rates:
The CSG industry depletes aquifers. The Federal Government’s Water Group estimates the industry will draw at least 666 and up to 5,400 gigalitres of water out of the ground each year. For comparison, Australian households use a total 1,872 gigalitres per year.
A 2009 NSW Office of Water report into drinking water catchment health said: “Groundwater is a significant resource in most catchments … As well as being extracted for town supply, stock and domestic use, and irrigation and industrial use, groundwater is a major contributor to base flow in rivers and streams in dry periods, and in maintaining wetlands and other groundwater dependent ecosystems: Excessive extraction for human use can decrease the amount of groundwater available for maintaining surface aquatic ecosystems, and can also lead to salinisation of the resource.”
CSG mining results in fugitive methane emissions – a highly flammable and potent greenhouse gas. These emissions come from leaking pipelines, wells and processing plants, methane in produced water, and methane escaping through underground systems.
Researchers from the US National Oceanic and Atmospheric Administration said air sampling of unconventional gas fields in Colorado showed leakage rates of 4% on average, and up to 7.7%.
This leaking methane can easily be ignited by sparks or cinders, and lead to fires that threaten water quality. The NSW Office of Water report said: “Bushfires can have devastating effects on catchment health, destroying native vegetation, farmland and infrastructure. Areas burnt by bushfires are prone to accelerated soil erosion, resulting in enhanced sediment and nutrient export to the surface water bodies downstream. Removal of vegetation by fire also reduces the ability of catchment areas to retain rainfall.”
CSG exploration and mining requires a well every 300 to 900 metres, connected to roads and pipelines, pumps, generators, compressors, ponds or tanks and storage facilities. Contrary to industry advertising that depicts CSG wells as a minor feature on the landscape, CSG fields have a big industrial footprint. This requires clearing and degradation of large areas of land.
But plants along rivers and streams, native vegetation and wetlands are vital to catchment health. Plants stabilise river and stream banks, and reduce erosion and flooding. Native vegetation in catchments retains rainfall and lowers the risk of excess runoff and flash flooding. It reduces soil and groundwater acidity and salinity, and lowers soil and nutrient loss into waterways. Likewise, wetlands store runoff, sediments, nutrients and other pollutants and reduce flooding.
It’s astonishing that this industry is being encouraged to proceed, with no scientific studies conducted into the impact of production CSG mining in our water catchments, or into the combined impacts of CSG and other mining activities (such as long wall mining) – a significant factor considering damage already in evidence.