The application comes two months after the Allan government committed to fast-track approval processes for quarries as a way to feed record demand for raw materials for construction.

Twelve months out from a state election, the decision is a test of the pull between the government’s hunger for raw materials for its Big Build agenda, and its attunement to local health and environmental concerns in a marginally Labor-leaning seat that has never been considered safe.

On Wednesday, Labor MP for Monbulk Daniela De Martino rose in parliament to condemn the expansion in a constituent question to her more senior colleague, Kilkenny.

“The incredibly close proximity of the proposed expansion to local schools and early childhood learning centres and residents, the removal of the ridge and bushland – which provide natural buffer zones from the dust and noise – as well as the environmental impacts of the proposed removal of bushland are worrying for us all,” De Martino said.

Annabel Brown, principal of Ghilgai Steiner School, about one kilometre south of the quarry, travelled to Sydney this month to take the fight to the board of Boral’s parent company, SGH, at its annual general meeting.

Brown said she was concerned about the Steiner school’s young children being exposed to dangerous dust particulates and noise.

“Currently, we don’t experience a whole lot of effects because the blasting and the mining action is generally down quite deep in the pit,” Brown said.

“But this expansion would bring it 33 acres [13.4 hectares] in the direction of our school, and with all of the action close to the surface, so it’s particularly concerning.”

Paul Barton, Ghilgai’s acting principal, said it would be difficult to explain the quarry expansion to the school’s children if it went ahead without an environmental effects statement. “We teach them the government is there to look after us. And when we have a government that looks like it’s about to take a big shortcut on health and safety, it’s in contrast with what we’re teaching.”

Boral was fined $180,000 in 2023 for failing to provide a safe workplace, after several Montrose quarry workers were exposed to unsafe levels of potentially lethal silica dust.

The company has provided conflicting information about the amount of rock remaining in the quarry. In its referral to the Department of Transport and Planning in October, the company said the quarry had just 18 months’ supply before it was exhausted.

If the proposal is rejected, Victoria “would prematurely lose a significant source of quality construction aggregates that is well located to serve the Melbourne market”, Boral said.

But this week, it confirmed to The Age that there was, in fact, eight to 10 years’ supply remaining.

The $380 million expansion project would extend the size of the pit by 12.7 hectares, claiming almost nine hectares of native vegetation and 262 large native trees.

A Boral spokesperson said the proposal was developed using suitably qualified, independent environmental assessments.

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“The project has considered how to avoid or minimise impacts associated with dust, vibration, air quality and noise, with robust and best-practice modelling that has been verified using site data collected at Montrose Quarry,” they said.

The spokesperson said strict national safety regulations applied to protect neighbouring homes, buildings and public places from the potential effects of blasting that were well below the vibration levels which could cause structural or cosmetic damage to structures.

An Allan government spokesperson said it would be inappropriate to comment while the project was under consideration.

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