MACH Energy has foreshadowed that it has an alternative plan to progress the expansion of Mt Pleasant mine should a legal challenge to its existing approval succeed.
The Denman, Aberdeen, Muswellbrook and Scone Healthy Environment Group is seeking a judicial review of the Independent Planning Commission's approval of the optimisation project in September 2022.
The project will extend the mine's life by 22 years to the end of 2048.
It will also deepen part of the open cut mining area, allowing for the extraction of approximately 444 million tonnes of run-of-mine coal over the project's life.
Extraction rates will also increase from 10.5 to 21 million tonnes per annum.
The Environmental Defenders Office, which is representing the community group, has argued that the commision failed to adequately consider the project's impacts on climate, biodiversity and air quality.
The NSW Land and Environment Court is expected to deliver a ruling in the matter next week.
MACH Energy issued a scoping letter in December last year foreshadowing its intention to submit a fresh application (MOD 7) for the project.
The new application would effectively do the same as the optimisation project, should the court rule against the commission's approval.
In a letter to the Department of Planning and Housing and Infrastructure' executive director, resource assessments Clay Preshaw, the EDO advised that any such application would be illegal.
"The (planning) minister cannot reasonably be satisfied that MOD 7 is 'substantially the same as the original development' (as modified by MOD4), as is required by section 4.55(2)(a) Environment and Planning Assessment Act 1985 (NSW) (EPA Act) read together with the transitional provisions of s75W. In these circumstances, the Minister, and or the Department as his delegate, does not have power to approve MOD 7," the letter states.
MACH Energy declined to comment on its plans.
Earlier this year the Federal Court upheld federal Environment Minister Tanya Plibersek's refusal to assess the climate impacts of the Mount Pleasant mine.
The Environment Council of Central Queensland took Ms Plibersek and and MACH Energy to court for failing to protect the environment from climate harm resulting from new coal and gas projects.
The court found that, under existing environment laws, the minister was not legally required to assess risk to the environment from the climate harm of the coal mine expansions.