A CONFIDENTIAL report containing details of the cultural significance of Ravensworth homestead may yet put a stop mining giant Glencore's plans to expand Glendell coal mine near Singleton.
The Independent Planning Commission was expected to make a determination this week on Glencore's plans to more than double annual production at the mine for the next two decades.
However, the IPC is now considering, and has asked for feedback on the Leo Report, at the request of the Environment Defender's Office, which is acting for the traditional owners of the land, the Wonnarua people.
The IPC has been directed by the relevant federal government department to keep the report confidential.
The IPC is also being asked to review correspondence between the Planning Department, Heritage NSW, and the chair of the state's Heritage Council.
A series of emails, which Lock the Gate Alliance obtained under the Government Information (Public Access) Act, reveals deepening tensions between NSW Planning and the Heritage Council, which acts as a government advisory body and which has opposed Glencore's plan to relocate Ravensworth homestead to a nearby farm.
The IPC had asked NSW Planning for a further assessment of all matters raised by Heritage NSW and the Heritage Council, however, in an email exchange between Elizabeth Owers, Director Customer Service, Heritage NSW, and Heritage Council Chair Frank Howarth, Ms Owers said their input was not needed.
"... we have clarified with the Planning team that they only want a response from HNSW on Ravensworth", Ms Owers said.
In response, Mr Howarth said he was surprised. "I find it a bit surprising, in that the IPC in their letter to DPE said specific things about the HC's positions and clearly is expecting a response to those issues from the HC."
Commenting on the emails, Lock the Gate has told the IPC it was "inappropriate" for the DPE to act as a gatekeeper and "prevent the IPC from hearing from the Heritage council on this crucial matter, in spite of the IPC's very clear request that all matters be addressed."
Experts have told the commission that there are few homesteads of Ravensworth's nature nationally, and its removal would strip it of its cultural and historic significance.
Colonial records show a series of attacks and counter-attacks between Aboriginal people and settlers occurred at the estate and the adjoining Lethbridge Estate between 1825 and 1826.
In late 1826, Governor Darling sought revenge for the murder of two settlers and destruction of crops. A posse of mounted police and settlers hunted down and massacred 18 Aboriginal people. The Plains Clan of the Wonnarua People have sought Commonwealth protection for the area on that basis.
The IPC said it will hand down its decision six weeks after receiving a further assessment from NSW Planning taking into account all new information.