The majority of workers at a meeting at Gunnedah Town Hall on Monday voted for the negotiated agreement put forward by the CFMEU.

This means staff will return to work sooner than the original lockout period of nine days, and the union and Idemitsu would enter into a "three-week cooling off period that extends until Sunday, December 15".

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Boggabri Coal chief operating officer Steve Kovac confirmed the agreement via an email to CFMEU district president Peter Jordan during the meeting.

"During the cooling-off period there will be no industrial action by either party including lockouts, strikes or other types of action on site e.g picket lines ... bans on specific work etc," Mr Kovac wrote.

Representatives from both parties, including Mr Jordan and Mr Kovac, will now meet to continue talks about Idemitsu's proposed new enterprise agreement.

Mr Kovac said Boggabri Coal would "facilitate an orderly return to work from Wednesday".

"We are hopeful of constructive dialogue with the union and other workforce representatives [in the cooling-off] period."

Idemitsu put the lockout in place after 88 per cent of workers voted 'no' to this proposal, because they were concerned about:

"Workers at Boggabri are not asking for anything that isn't already provided to workers at Muswellbrook and Ensham," Mr Jordan said.

"Boggabri produces top-quality coal and there's no reason why these workers should be treated differently, with worse pay and conditions, just because they are in the Gunnedah Basin."

Union members have held strikes and stoppages since the end of August to fight the agreement.