Queensland-based Mantle is in the process of exploring 15 Moorabool sites for coal after it was issued an exploration drilling licence for a 38,000-hectare area around Bacchus Marsh.

It hopes to eventually build an open cut mine and export coal to India.

Bacchus Marsh police attended the Glenmore Road site, on public land near the Bacchus Marsh Airport, following the arrival of about 20 protesters.

Bacchus Marsh mother Natasha Mills said she shackled herself to the coal rig because an open cut mine in the region could lead to a "disaster".

Ms Mills, due to give birth to her second child in six weeks, said she wasn't only concerned for her family but the wider community.

"There has been no consultation with the community. No wonder people are outraged, and we're in the middle of a food bowl. This will be a massive open cut coal mine. It will trash the environment and this area is an agricultural town."

Quit Coal activist Paul Connor scaled an eight-metre rig and chained his ankle to its tip.

"For these companies to look at setting up a brown coal export when this area grows plenty of the food we eat in Melbourne, it's just wrong and I'm determined we're going to to stop it," Mr Connor said.

"[The consultation] was obviously inadequate. The locals don't feel like they have had a say."

Mantle's exploration manager Callum Lamont told the Weekly he was concerned for the objectors' safety.

"Most of my job is tied into safety so this absolutely worries me. We have signs and barriers set up, but these people continue go on the site all the time."

Police remained at the scene yesterday afternoon. Ms Mills was asked to detach herself or face being charged with interfering with a vehicle.

Mr Connor refused to detach himself and police were attempting to unchain him. He was expected to be charged.

The protest followed a parliamentary inquiry last week when Mantle's managing director, Ian Kraemer, fielded questions on whether the local community had been properly consulted before the issuing of an exploration license.

Mantle advertised its plans in a local newspaper when applying for the exploration licence, as required by law, but opponents claim most residents were unaware until the company began letterbox-dropping flyers in August last year.

Mr Kraemer argued Mantle had abided by all legislation during the consultation period and before the licence was issued.