The company is also proposing to utilise and upgrade the existing infrastructure at the mine surface facilities site, and transport coal by road to domestic markets and the Port of Newcastle.

The proposal will involve the extension of underground mining within the Fassifern Seam in five areas identified as Areas 1A, 1B, 1C, 1D and 1E.

Areas 1A, 1B and 1C are within mining leases held by Centennial Coal for its Mannering Mine and Myuna and Mandalong collieries, while areas 1D and 1E are within existing LakeCoal holdings.

No mining has been undertaken in the Great Northern and Wallarah seams overlaying Area 1, except for parts of Area 1E, which are located beneath the colliery’s historic workings.

The proposed miniwall panels within Area 1 would have a maximum face width of approximately 86.2 m and a maximum width of approximately 97m with all secondary extraction confined to areas under the Lake Macquarie water body.

Reserves within Area 1 have been estimated at 19.5Mt of ROM coal.

The director-general of planning has made specific recommendations for the proposal including the management of subsidence.

He has asked for “a detailed quantitative and qualitative assessment of the potential conventional and non-conventional subsidence impacts of the development that includes accurate predictions of the potential subsidence effects and impacts of the development, paying particular attention to the long-term stability of final pillars, including a robust sensitivity analysis of these predictions”

The subsidence assessment should also include predictions of the potential cumulative subsidence effects and impacts from the development in conjunction with overlying and adjacent mining including a “robust sensitivity analysis of these predictions”

A detailed assessment of the potential environmental consequences of these effects and impacts on both the natural and built environment, paying particular attention to Lake Macquarie, including its bed, seagrass beds and foreshores and other features considered to have significant economic, social,cultural or environmental values would also be required.

The director-general asked for a detailed description of the measures that would be implemented to avoid, minimise, remediate and offset subsidence impacts and environmental consequences – including adaptive management and proposed performance measures.