After months of stalemate, the newly sworn in Federal Environment Minister has swooped in to apply a water assessment to major mining projects in the Hunter.

50 coal seam gas and coal mine projects around the country were being examined to see if new water protection legislation known as the Water Trigger would apply.

But after months sitting with the former Labor Government, only four were assessed to come under the Bill.

They were then revoked, to be decided by the new minister, Greg Hunt.

He has now applied the Water Trigger to 47 of the 50 projects, with some in the Hunter and Central Coast.

They include controversial ventures like the Wallarah 2 mine, Drayton South and the Stratford Mining Complex.

But the Minister is seeking advice on a further project, the Mount Penny Coal mine in the Bylong Valley, thrown into the spotlight with recent ICAC findings against its directors.

Mr Hunt says he needs to know whether it is even appropriate to consider Mt Penny.

"I think it's very prudent to be cautious on an application with a project that has such a clouded legal history about it," he said.

The Minister has also sought information from the New South Wales Attorney General about the proponent's environmental record.

The decision to apply a water assessment to a number of mining projects throughout the Hunter is being hailed as a great move for the region.

Gloucester Groundswell's Julie Lyford says she is very happy the Stratford coal mine is included in the minister's list.

"I really commend the minister for making that decision," she said.

"I think it certainly shows he takes the environmental risks to water and our agricultural places very seriously and that's certainly welcome news for what's happening in Gloucester."