Kiama Municipal Council has slammed Boral's proposal to expand its Dunmore sand mine on the Minnamurra River, saying the expansion brings a higher risk of environmental damage, and should be treated as a separate development.
The Planning Department should "terminate the current assessment process and consider this a new proposal", councillors said, while "potential impact on flora and fauna is likely to be significant and has not been evaluated sufficiently".
Independent NSW MLC Justin Field has also added his voice to the opposition, as public submissions to the Major Projects assessment came to a close.
Boral wants to dig two new pits within a 38ha site of mostly agricultural land east of the Princes Hwy and south of Riverside Dr, to feed growing demand for sand in the Sydney construction market.
About 1.1 million tonnes of sand would be extracted from one pit dug to a depth of 27m (stage 5B), and 234,000 tonnes from the other, up to 12m deep (Stage 5A).
But the smaller pit would come to within about 100m of the Minnamurra River, Boral's plannning documents show, concerning residents about the potential impact on the popular swimming, fishing and boating spot.
At Tuesday night's meeting Kiama council left residents in no doubt of their position, voting unanimously to send "strong opposition" to the Planning Department.
"The areas proposed in [the modification] are physically separated from those considered in the original approval and have a far greater likelihood of causing environmental impact," council said.
"Areas 5A and 5B are both located in very close proximity to the Minnamurra River, and unlike the existing extraction areas, has the potential to impact on ecologically important ecosystems."
This would have "impacts on tourism and the scenic amenity that is of very high value to the Kiama community," council said.
Mr Field this was the wrong spot for sand mining.
"There are significant community concerns about the impact on the river which is a popular fishing location," he said. "These are critical habitats for marine and bird life and iconic species like the Greater Glider and should be protected.
"There is a need to supply sand for construction but there are alternative locations that don't risk the natural environment and tourism values of the region."
Boral's operating hours would not change and its tonnage limit would remain at 800,000 per year. Post-extraction, the company said it would rehabilitate the Stage 5A area, filling it with natural materials and vegetation to return the land to pasture.
The 5B pit would "be left as a freshwater pond".