On Tuesday the NSW Scientific Committee made a preliminary ruling to support a proposal to list alteration of habitat following subsidence due to longwall mining as a key threatening process. If approved, the ruling could force additional environmental compliance measures onto coal mining giants like BHP Billiton and Centennial Coal.
The ruling is not yet legal, with final decision due early next year. Public submissions are being sought on the ruling until January 28.
If approved the department of Environment and Conservation will consider whether to implement new measures to reduce subsidence threat to habitats or whether existing measures are sufficient.
The ruling specifically targets mining under water where subsidence can cause cracking of valley floors and creeklines, which affects surface and groundwater hydrology.
In its report, the Scientific Committee cited a long list of water courses that had substantial damage from subsidence including North Wambo Creek, Upper Nepean, Cordeaux and Cataract catchments.
It referred back to perhaps the most notorious subsidence case at South Bulli where cracking of the Cataract riverbed caused the river downstream of mining to dry up. Water that re-emerged downstream was notably deoxygenated and heavily contaminated with iron deposits.
Other cases named included the Georges River affected by the West Cliff longwall and the Wongawilli Creek affected by Elouera.
The Committee said mitigation measures, specifically grouting, to repair cracking creek beds had experienced limited success.
The Greens and residents making up the Nepean Action Group (NAG) – which has been battling BHP Billiton Illawarra Coal’s plans to extend Appin under the Nepean River - have welcomed the decision.
“The NSW Scientific Committee has put the writing on the wall for governments and coal mining companies. Even in draft form, it clearly vindicates the communities and groups who have argued that longwall mining is an outdated, destructive mining technique,” Greens MP Lee Rhiannon said.
“Longwall mining under the Cataract and Georges Rivers has cracked the river beds, resulting in massive ecosystem damage and water losses.
“Communities are no longer prepared to accept this damage, and the NSW Scientific Committee has given added weight to their ongoing campaign to change mining practices and make mining giants accountable for the environmental damage they cause.”
BHP Billiton Illawarra Coal spokeswoman Rosanne Moore told the Illawarra Mercury alternative mining layouts had been investigated and would be presented at meetings with NAG and stakeholders. The groups have held meetings this week in Appin.
