Concern has been raised about the effect of a coal mine expansion on key swamplands in NSW. 

Threatened habitat and species could be put at greater risk if Centennial Coal’s Angus Place Mine is allowed to expand, according to environmentalists. 

The company has applied to carry out longwall mining underneath swamps listed as endangered ecological communities.

Centennial was fined $1.5 million in 2010 after it damaged the East Wolgan swamp.

The same company's Springvale Mine, also near Lithgow, has been found to have contributed to the drying of Carne West Swamp on Newnes Plateau.

In its latest expansion application, Centennial Coal's own environmental assessment (EA) says “subsidence-related impacts are expected at Tri-Star Swamp, Twin Gully Swamp, Trail Six Swamp and the hanging swamps within their catchments”.

The Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Developments (IESC), which advises federal departments, says that expanding the mine would lead to “the severe and irreversible loss” of these swamps, and the partial drying of others.

The IESC warns that the project is likely to reduce surface water flows, which would adversely affect streams flowing into Sydney's drinking water supply at Warragamba Dam.

The miner says it is impossible to avoid the areas underneath the swamps, because that would make a large area of the site non-viable for mining.

The NSW Department of Planning is currently considering the plans.