Australian Pacific Coal (AQC), Dartbrook's owner, told the market on Tuesday morning it had received a joint venture offer from Queensland coal company, Tetra Resources, and coal management firm Javelin Private Group LLC.

The offer proposes Tetra would hold a 40 per cent share in Dartbrook, along with marketing and loan agreements between Javelin and AQC.

Tetra's offer is the most recent in a series made to AQC this year, two involving coal magnate Nathan Tinkler.

AQC are currently "working towards a binding agreement" with M Resources following a 50:50 joint venture offer.

Separate to the new offer on Tuesday, AQC released an investor presentation to the market on a proposal to recommission the mine.

The presentation indicated the company would aim to extract "first coal" from Dartbrook in the second half of 2023.

Dartbrook's license, valid until December 2027, limits production to six million tonnes per annum for a combination of longwall and board and pillar mining. The presentation said the estimated replacement value of mining infrastructure at the site to be $300 million.

The mine closed in 2006 after three mining fatalities in a decade. AQC noted a combustion risk in their presentation.

"The Dartbrook Coal Project tends towards a medium to high spontaneous combustion risk particularly in the old longwall areas where the risk is much higher," the presentation said.

"The exposure of the old workings increases the risk of re-activation of dormant heating or the commencement of new heating."

The presentation also outlined in detail an entitlement offer process the company is currently undertaking which allows investors to purchase extra shares in an effort to raise $100 million in capital.

Around $70 million of the money raised will go toward paying off existing debts, more than half of which has accrued as interest.

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