The department’s submission to the Department of Planning is considered critical to the project’s assessment because Coal & Allied has proposed mining on alluvial river plains.

The project, 24 kilometres north-west of Singleton, is being assessed under Part 3A planning laws.

Upper Hunter land and water users have already warned of potentially disastrous environmental consequences to the Hunter River if the project is approved.

Coal & Allied has argued that a groundwater barrier wall would minimise possible seepage and damage to the river system.

It also says similar areas have been successfully rehabilitated as productive agricultural land following mining.

Submissions for the project closed on October 5. An Office of Water spokesman said last week that the department was still finalising its submission.

‘‘It is intended this response will be submitted early in the new year,’’ he said.

The Department of Agriculture is also yet to provide a submission for the project.

A Department of Planning spokeswoman said it had worked closely with the Office of Water as part of the Director General’s Requirements.

‘‘The department will consider all submissions received, including submissions received after the closing date, as well as the proponent’s response to submissions,’’ she said.

A Department of Environment and Climate Change submission warned that dust emissions from the project could be 42 per cent higher than what was stated in the environmental assessment report.