Radical new rules for assessing large mining projects in NSW risk serious damage to Sydney’s drinking water supply, the government agency set up to protect water quality has warned.
The Sydney Catchment Authority says the city’s drinking water catchments, spanning 16,000 square kilometres, should be exempt from the changes proposed by the O’Farrell government. It also called for a ban on longwall mining near major lakes and reservoirs.
The government’s proposal would increase the odds that mining projects are approved by making their economic benefit the “principal consideration” of the assessment process.
But the authority has warned the changes were concerning and could lead to “increased risks” to the Sydney catchment, which supplies water to 4.5 million households and other users. It may also damage water supply infrastructure including dams and pipes, cause loss of water from storages and degrade water quality, it said.
The Planning Department says underground mining has been allowed under water catchments for decades and it would not support projects that “adversely impact on Sydney’s drinking water supply”.
But the authority’s submission said damage to infrastructure, watercourses and swamps from longwall mining had already occurred, including on the Upper Canal. It says the canal is the only way that water can be transferred to Sydney from upper Nepean dams.
The authority has recently received advice on “the long term potential for damage” from longwall mining, it said.
Longwall mining involves removing a panel of coal along a face up to two kilometres long. The Office of Environment and Heritage says it can cause land above to destabilise and collapse and create cracks under streams or other water bodies which may lead to water loss. It can also contaminate water.
The catchment authority called for a ban on longwall mining in areas immediately surrounding major water storages. It said the proposed rules should not apply to Sydney’s drinking water catchments, or at least the so-called “special areas” - 371,000 hectares of bush that act as a buffer to stop nutrients and other substances from affecting water supply.
The catchment authority’s submission was made in August and signed by former chief executive Ross Young, whose contract was terminated last month - less than one year into a five-year term. The government would not say why he left the position.
In February the Planning Department approved an extension to the Dendrobium mine south of Sydney, operated by a BHP Billiton subsidiary, despite concerns by the authority it would lead to cracking and divert stream flows.
In August, Fairfax Media revealed a large section of Sugarloaf State Conservation Area in the Lower Hunter had been destroyed by subsidence from a longwall mine. A waterway had also been accidentally grouted by workers carrying out remediation works.
The government says the new rules will increase certainty about how decisions are made on mining proposals.
NSW Minerals Council chief executive Stephen Galilee said independent research in the southern coalfield in 2009 found “no evidence to support the blanket banning of underground mining in the catchment area”.
A senior lecturer at the University of NSW, Stuart Khan, said the catchment authority’s recommendations should be adopted, adding “this is the strongest statement I’ve seen”.
