ABORIGINAL artefacts unearthed in a unique $1 million archaeological excavation at a Hunter Valley open-cut coalmine site may be up to 50,000 years old, it was revealed yesterday.

If luminescent and radiocarbon dating next month confirm preliminary estimates of stone implements and rock shavings found in shallow dig pits it will connect the area, 15 kilometres west of Singleton, with the arrival of Aborigines in Australia.

Scarp Archaeology spokesman Michael Slack said this would make the excavation one of Australia's most significant archaeological sites.

Scarp is providing technical advice for the project, which began on Coal and Allied Industries' Mount Thorley Warkworth mine last month.

The dig, scheduled to be completed next month, is the biggest and most expensive archaeological excavation undertaken by the company and the first Hunter coalmine dig involving traditional Aboriginal land owners.

It is being done as part of Coal & Allied's process to obtain approval to continue mining the area.

Twelve representatives of the Wonnarua Nation have been involved in excavation work. Spokeswoman Tracey Skene said the dig held great heritage importance for her people.

Mount Thorley Warkworth operations general manager Cam Halfpenny said: "We believe it is possible to balance the needs of the mine with the needs of our local Aboriginal community."