One of the largest goldmines in the world will have its expansion approval put on hold after failing to meet a key condition of its production increase.
Newcrest's Cadia Valley Operations (CVO) near Orange has been found to be non-compliant by an independent air quality audit which revealed one vent shaft was emitting 18 times what is legislated as safe amounts of carcinogen respirable crystalline silica.
In a statement, NSW's Department of Planning and Environment said they were investigating the matters raised in the independent audit report in collaboration with the NSW Environment Protection Authority (EPA).
In December 2021, a delegate for then-planning minister Rob Stokes approved the mine's Modification 14 which sought to fix the northern tailings dam wall slump and increase ore production from 32 million tonnes per annum (TPA) to 35 million TPA.
A key condition placed on the modification's approval was that an independent air quality audit report be approved by the planning secretary before production could increase.
The Zephyr Environmental Independent Air Quality Audit was commissioned by Cadia and approved by the planning secretary in February and completed in August this year.
It returned two non-compliance findings in a final report dated October 2022, which will see the company's production increase disallowed.
Crusher vent unrestrained
The report found CVO had failed to submit an Air Quality Validation Report to the department by March 2022.
It also found evidence of elevated emissions from ventilation shafts or "rises" in the mine's ventilation network which suck polluted air from Cadia's underground mining operations and disperse it into the atmosphere.
VR8-1, known as the "crusher vent" because it extracts contaminated air from the point where ore is pulverised underground, was found to be expelling 360 milligrams per cubic metre of air of particulate matter including known carcinogen respirable crystalline silica – 18 times the regulatory limit of 20mg/m3. Vent shaft 3 (known as VR3-1) was also found to be in exceedence.
Neither VR3-1 nor VR8-1 were found to have dust mitigation measures in place such as misting sprays, dust collectors or a "scrubber system" used for crusher vents like VR8-1 that deal with high volumes of particulate matter.
In response to the report's findings, Cadia's acting general manager Mick Dewar said the company had engaged a number of mitigation measures.
"As well as implementing short-term controls, such as additional dust suppression sprays at the two vent rises and additional air quality monitoring on the surface," Mr Dewar said
"Cadia has implemented a dust working group and commissioned an engineering study supported by the University of Wollongong to implement dust control technologies at the source to further mitigate particulate matter from being discharged through the vents."
Mr Dewar also said the company was working "proactively and constructively with the department to address these non-compliances, and continues to communicate openly and transparently with the local community."
Air pollution underestimated
Hailed as a win for the community when it was announced last year, the independent air quality audit has provided previously elusive details on dust make-up and drift.
By examining the dust dispersion modelling used in Modification 14's initial project application by Cadia and its consultants, the audit was also able to establish "considerable" under-reporting of particulate matter.
Resident's group Cadia Community Sustainability Network (CCSN) said these historical holes in the company's monitoring and modelling made obtaining an accurate picture of community exposure all but impossible.
"We all expected and trusted Cadia to comply with Australia's environmental laws and health and safety standards," CCSN chair Gemma Green said
"It is very distressing to find out that CVO has been operating without installing the most basic dust mitigation measures and has been telling the community for years there is no dust coming from the stacks.
"We believe a licence to mine our national resource is a privilege, particularly when that resource is in close proximity to people's homes."
Mr Dewar said the potential exceedence of particulate emissions from two vent rises had only been recorded at the source.
"Exceedences have not been detected at any of the four off-site air quality monitoring locations that form part of Cadia's comprehensive air quality monitoring network."
A timeline for when the production increase might be granted is unknown, with a spokesperson from DPIE telling the ABC that they expected Newcrest to provide solutions first.
"The department has sought additional information from the applicant on how the matters raised in the audit will be addressed, and the timing for implementing those measures," the spokesperson said.
