Wollongong Coal’s plan to extend longwall mining has been approved the by the Planning Assessment Commission.
Earlier this year the company sought permission to mine a 400 metre block of longwall 6 at Russell Vale mine as a make-do measure until its major extension project is processed by the government.
The company said it would have to shut the mine unless it was granted permission to access a section of the longwall which holds 260,000 tonnes of coal.
This will allow mining to continue at the site until December 2015.
Environmental groups have previously criticised Wollongong Coal’s plans to mine longwall 6, claiming it poses a major threat to the water catchment area.
PAC noted these concerns in its assessment and downgraded the section that could be mined from 400 metres to 365 metres.
"The commission finds a cautious approach should be adopted given the uncertainty of integrity of the swamps from previous mining … and the risk of reaching the swamp's tipping point," PAC said.
The commission said the longwall was "extremely unlikely to have any impact on the dam wall" and said any loss of groundwater would not be significant.
However PAC did take aim at the mine’s “picemeal incremental approach to planning and assessment”.
“The Commission noted that this is the third time that the maintenance of employment of existing mine workers is used as a justification to seek incremental approval for a small area in the absence of a comprehensive expansion plan,” it said.
“The credibility of the employment justification is wearing thin.”
PAC said it would be of benefit to all stakeholders that the expansion plan be assessed and determined “expeditiously”.
The full proposal includes the construction of a longwall approximately 1.12 kilometres long and 150 metres wide.
Isabel McIntosh, from Protect Sydney's Water Alliance, said the approval was disappointing, The Illawarra Mercury reported.
"The subsidence from this longwall very likely will cause significant damage," McIntosh said.
"This new longwall is a high-risk experiment and it certainly should not be taking place in a water catchment that supplies more than 4½ million people.”