The campaign is more than two weeks old with four protest groups blocking the Leard State Forest entrances while another two groups are in project areas preventing contractors from working.

Photographs reveal that the onsite protestors linked up trucks and other mobile construction equipment with what looks like steel cable to large monopod or tripod structures.

Each of these structures suspend a locked-in protestor several metres up from the ground.

The Lock the Gate Alliance said 91-year-old Kokoda veteran Bill Ryan took part yesterday with his 65-year-old son.

“The men and women taking part in this blockade have been compelled to make sacrifices and put themselves at risk of arrest to protect something of great value,” Leard Forest Alliance spokesperson Georgina Woods said.

“This mine should never have been approved – [federal] Environment Minister Greg Hunt can put a stop to all of this by revoking the approval that was mistakenly given to clear this forest for coal mining.

“We certainly won’t be giving up on this community, this forest and the people that love it.”

She told the Sydney Morning Herald yesterday that the protestors were basically digging in to stop the contractors from using machines to clear the forest.

“It's not going to end until this forest gets a reprieve,” she told the newspaper.

As of yesterday police had reportedly arrested at least 10 protestors since the blockade started a fortnight ago.

The forest was reportedly declared closed to the public until March 31 due to fire risks while the Narrabri Council recently rejected an appeal to its Maules Creek-motivated plans to force campers off its public lands.

“Legal advice is now being sought by Narrabri Shire residents as to whether the decision by Narrabri Council is actually legally binding, as they may not actually have the power to make the call,” Lock the Gate said yesterday afternoon.

Greens NSW Senator Lee Rhiannon was part of the protest group yesterday with her party claiming that 15 machines were immobilised.

“The number of people willing to give up their time to prevent the Maules Creek mine from going ahead is inspiring,” she said.

While the LFA-related statement suggested there were 100 protestors, the Greens claimed that 150 had gathered.

Contractor Leighton started mobilising to the site in December.

Rail spur construction is expected to take 13 months with first coal production due in the first half of 2015.

Targeting 13 million tonnes run of mine, the open cut project is about 17km northwest of the main rail line that links the Boggabri town.

Lock the Gate is seeking to challenge the state and federal environmental approvals for the project based on its claims of errors with the project’s biodiversity mapping.