The merits class 1 appeal by Ironstone Community Action Group versus the NSW planning minister and Gloucester/Duralie Coal over further mining approvals has been part-heard at both Gloucester Court House and in the Sydney Land and Environment Court.

It is listed now to continue in Sydney on Monday June 27 and Friday July 1.

Concerned members of the public have been invited to attend the hearings and support the community's case in defending the environment of the Gloucester region from destruction and pollution by mining activities.

Meantime the Newcastle Herald has revealed that about 20 per cent of Gloucester Valley houses sampled for heavy metal contamination in their soil and tank water have returned levels above national guidelines.

Macquarie University researchers took samples from 101 houses last October in response to community concerns about the mines' health impacts.

The results showed between 10 and 20 per cent of the water samples contained levels of lead or zinc that were above drinking water guidelines, and some had high levels of nickel and copper contamination.

The Herald said independent testing cleared the nearby Duralie coal mine as the source of the contamination.

The university's Associate Professor Damian Gore said the issue of dust pollution was outside the study's scope.

"I don't think the mines can walk away smug at all because the amount of dust I am seeing in some samples is inexcusable," he told the Herald.