In a crowded room at Bacchus Marsh Public Hall, residents were joined by politicians from all levels of government, including Ballarat MP Catherine King, Greens' Senator Richard Di Natale, Melton MP Don Nardella and Moorabool mayor Pat Griffin.

Last week's meeting was the culmination of months of anxiety over Mantle Mining's licence to search for brown coal in Moorabool.

The licence covers 38,000 hectares, including Bacchus Marsh, Darley, Myrniong and east of Ballan.

Mantle intends to start an open-cut coal mine. Exploratory drilling at rig sites in the Parwan area began last week.

Residents voiced their anger about the DPI's application process for the exploration licence, with Mantle required to advertise its plans only in a small newspaper notice.

No hands were raised when prominent Melbourne lawyer Rob Stary, who chaired the meeting, asked how many residents had known about Mantle's exploration licence application.

DPI spokesman Doug Sceney tried to allay residents' fears and said the early phases of exploration were low-impact.

"An exploration licence doesn't actually allow you to do anything other than things you might do with hand tools, unless you get further approvals," he said.

But in comments to the Weekly, Energy and Resources Minister Michael O'Brien said Mantle had been given permission to use more intrusive drilling procedures.

"Under an exploration licence, the holder can only undertake low-impact exploration - the use of non-mechanical hand tools - until an approved work plan is in place," he said.

Senator Di Natale said he would urge Mantle Mining to listen to the community's concerns.