BHP plans to extend the life of the mine by continuing longwall mining under the Nepean River but is facing opposition from local community groups.

In the recent past longwall mining in the area occurred under swimming and recreation spot Marhnyes Hole on the Georges River and caused cracking which led to water draining out of the area.

With some innovative engineering the problem was resolved but what survived in the popular imagination was images of destruction. This proved to be the catalyst for the introduction of a revised approval process for any underground mining that could lead to surface subsidence in the state.

This week a number of influential members of the Australian Labor Party (ALP) joined the Nepean Action Group, a campaign working to stop the extension of Appin.

New South Wales Mineral Resources minister Kerry Hickey met a delegation from the Nepean Action Group and the Wollondilly branch of the ALP.

The delegation included the Labor Member for Camden, Geoff Corrigan, and influential lawyer John Marsden. Campbelltown, Camden and Wollondilly councils have already passed motions opposing the plan.

New approval processes for extending the Appin colliery now depend on BHP Billiton being able to show it has addressed community concerns about the proposal and its possible consequences.

BHP Billiton has already spoken to 29 landowners whose properties would be directly affected by the extension of the company's activities.