The NSW Planning Department has given BHP Billiton a rap over the knuckles regarding its plans to commence longwall mining at its Dendrobium mine.
Earlier this month, the department approved the Subsidence Management Plan (SMP) for the Mt Kembla mine, which was required before longwall mining could commence. The SMP was a condition of the development consent issued in 2008.
Rather than allow mining in all 10 panels of Area 3B, as BHP Billiton has requested, the department allowed mine operator Illawarra Coal to start in only five of the panels, requiring further approval to mine the remaining five.
A spokesman said the planning department was unhappy that BHP Billiton had already developed underground roadways to the longwall panels prior to the SMP's approval.
"BHP was entitled to undertake these preliminary works under its 2008 approval," the spokesman said.
"However, it's the department's view that in the case of this mine this was not best practice, given that a later subsidence management plan approval was required."
The spokesman also expressed concern over the "relatively short time frame" the department was given to make a decision, stating that BHP Billiton should have submitted its draft SMP much earlier than October 2012.
In a statement explaining the SMP approval, Department of Planning and Infrastructure Director-General Sam Haddad stated that the construction of these roads affected the decision-making process.
"The government's ability to further restrict the impacts of mining in Area 3B were substantially limited by Illawarra Coal's decision to submit the SMP to government well after roadway development for the first two longwall blocks had been completed."
A BHP spokeswoman said it had developed the roadways more than 12 months before mining began, adding "this is standard industry practice".
"As one longwall block is being mined, work is carried out to develop roadways which form the next longwall block for extraction," the spokeswoman said.
"This is essential to ensure minimal delays in moving the longwall equipment to the next block and thereby ensures continuity of employment and supply of coal to customers.
"A longwall machine cannot commence operations until the roadways around it are complete."
The spokeswoman claimed the company submitted the first draft of the SMP "for government agency review and feedback" in August 2012.
However, she said the company was happy to work with the industry and government to further define approval time frames.