There are fears threatened habitat and species which survived the Black Summer bushfires in the New South Wales Blue Mountains could be lost if a coal mine is allowed to expand.

Centennial Coal has applied to re-open its Angus Place Mine on Newnes Plateau, near Lithgow.

The company wants to carry out longwall mining underneath a number of swamps listed as endangered ecological communities.

Lithgow residents Chris Jonkers and his wife Julie Favell are avid bushwalkers on Newnes Plateau and have watched the landscape change.

They are worried about how wildlife will be impacted if the area is damaged.

"This is the kitchen, if you like. All nature comes to these tiny spots for food and water," Mr Jonkers said.

Damage expected at swamps

Centennial Coal's environmental assessment (EA) states that "subsidence-related impacts are expected at Tri-Star Swamp, Twin Gully Swamp, Trail Six Swamp and the hanging swamps within their catchments".

In 2010, the company was ordered to pay $1.5 million because of slumping at East Wolgan swamp.

It has also admitted its operations at its Springvale Mine, also near Lithgow, contributed to the drying of Carne West Swamp on Newnes Plateau.

Chris Jonkers said he feared the same fate awaited the swamps above Angus Place Mine.

The Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Developments (IESC), which advises federal departments, also paints a bleak picture for these sites.

Its advice stated that the mine would lead to "the severe and irreversible loss" of these swamps, as well as the partial drying of others.

Slow recovery after bushfires

There are still signs of the Gospers Mountain mega-blaze which tore through Newnes Plateau in late 2019.

Most trees were regenerating, but Ms Favell said Carne West Swamp had not recovered from the drought and bushfires like other swamps in the area.

"You may have some growth come back but it won't be at that level — at the pristine level," she said.

The IESC also warned the likely reduction in surface water flows would adversely affect streams that flowed into Sydney's drinking water supply at Warragamba Dam.

"This needs to be really heavily considered for future planning, for Sydney's population."

The mine's EA rules out the possibility of avoiding the areas lying underneath the swamps because it would mean a large area of the site would be not be viable for mining.

Mr Jonkers said he wanted Centennial Coal to consider using different mining methods that would minimise damage to the swamps.

He said bord and pillar mining, which involved leaving sections to support the roof, was used at two of its other collieries near Lithgow.

But in a statement, the company said it was an uneconomic mining method in the case of Angus Place due to the depth of cover and geology.

The mine's extension plans are currently before the NSW Department of Planning.