An administrative error has meant the NSW Heritage Council will need to reconsider its support for adding Ravensworth Estate to the state's heritage register.
The council resolved in April to recommend to Heritage Minister Penny Sharpe that the nineteenth century homestead, comprising of four sandstone buildings and a timber cottage, be added to the register.
The buildings form part of the broader Ravensworth Estate, near Muswellbrook, which is within the footprint of Glencore's proposed extension of the Glendell coal mine.
The Independent Planning Commission rejected the plan in late 2022 on the basis that it would have "significant, irreversible and unjustified impacts on the historic heritage values of the homestead complex"
Glencore chose not to appeal the IPC ruling, however, concerns remain that the historic buildings will be disassembled and relocated, possibly in Broke.
The Heritage Council's recommendation that the estate be added to the state's heritage register gave further weight to those campaigning to have the area preserved in situ
However, council chairman Frank Howarth recently wrote to stakeholders to advise that that the council had not been provided with all the attachments to a submission prior to making its decision.
The "administrative error" meant the decision made on April 12 had no valid effect.
Mr Howarth said the council would consider the matter again on November 21, "having regard to all the submissions and annexures to submissions made on this matter."
Minister Sharpe told a Budget Estimates hearing last week that she was expecting a recommendation from the council in the near future.
"I'm expecting it very soon. To be clear, I've met with Aboriginal groups," she said.
"I have been and visited the site and I have met with the mining company as well, but I am waiting on the final recommendation from the Heritage Council.
"Then I have to take into account all of that feedback, so I'm not going to indicate to you how I will deal with it. I take that decision very seriously."
The Heritage Council, which acts as a government advisory body, has consistently opposed the destruction or relocation of Ravensworth homestead.
It is considered to have cultural and historic significance dating back to 1825.
Colonial records show a series of attacks and counter-attacks between Aboriginal people and settlers at the homestead and the adjoining Lethbridge Estate.
Tensions between the groups culminated in late 1826 when, with the endorsement of Governor Darling who sought revenge for the murder of two settlers and destruction of crops, a posse of mounted police and settlers hunted down and massacred a group 18 Aboriginal people.
Historians are divided on the exact location of the massacre. Glencore disputes that a massacre occurred on the site of the proposed mine extension.