Virgin Excavated Natural Material (VENM) will be trucked in from construction sites across the Illawarra and tunnelling sites in Sydney. Boral will then process it and blend it with Dunmore sand to sell as construction sand.

The proposal has been approved without any public consultation.

But Boral will not be able to deposit the excavated material in the water before dredging it out again, as it wanted to do, following concerns from the Environment Protection Authority.

After the EPA raised concerns about depositing the VENM in existing ponds, Boral amended its plans such that the material would now go straight to the processing plant.

The Department of Planning and Environment had not put the proposal out for public exhibition, an assessment officer having decided the modification was "minor".

The Environment Protection Authority raised concerns during the assessment process, including over the "minor" classification which enabled the lack of public consultation.

"The transportation and processing of an additional 120,000 tonnes of VENM appears to be a major change to the operation of the premises," the EPA wrote.

"It appears the proposed processing of VENM is likely to mean that the VENM material will meet the definition of 'waste' ... [and] waste processing facilities may not be allowable under the Shellharbour LEP."

The Office of Environment and Heritage - since folded into the Department of Planning, Industry and Environment - wrote that it "has a nil reply on this matter".

Because this proposal was never put on public exhibition, there were no submissions from the public.

The modification was approved by a delegate of the department's director.

Boral is also seeking to expand its sand mining operation across the Princes Hwy closer to the Minnamurra River, a proposal which has sparked outcry from local residents concerned about the impact on the waterway. This proposal is still being assessed by the department.