Bodies of miners expected to be recovered today

INVESTIGATIONS are continuing at the scene of a coal mine collapse in the NSW Hunter Valley where the bodies of two workers are expected to be recovered later today.

Emergency services have confirmed the men, aged 35 and 49, were killed after becoming trapped 500m below the surface of the Austar mine, about 10km south of Cessnock, late Tuesday.

Two others were injured in the collapse which sparked a major rescue operation and shut down the mine until further notice.

Mining chiefs are yet to explain how the collapse occurred but it's understood an Australian-first mining technique known as "longwall top-coal caving" has been used at the mine since it re-opened following an underground fire almost 10 years ago.

Fairfax reported the underground incident forced owner Gympie Gold into receivership in 2004 and the mine was sold to Yancoal in 2006.

A crime scene has been established at the mine. A retrieval operation is currently under way.