The New South Wales (NSW) government has approved modifications to the planning consent for Newmont’s Cadia mine, which the company says will enhance the environmental performance of Australia’s largest underground mine while supporting jobs and continued investment.

Cadia operates under project approval PA 06_0295, which has been modified 14 times and permits the extraction of about 525-million tonnes of ore from the Cadia East Underground Mine and 96-million tonnes from the Ridgeway underground mine.

The approval also allows tailings to be deposited into the Northern Tailings Storage Facility (NTSF), Southern Tailings Storage Facility (STSF), and the Cadia Hill openpit, following a tailings breakthrough in the southern embankment of the NTSF into the STSF in March 2018.

Since the approval of modification 14 in December 2021, Cadia has undertaken repairs to the NTSF and reinforced both the NTSF and STSF embankments to enable their continued use. However, these facilities have not been operational since 2018 and 2021, respectively.

KEY CHANGES
Modification 15 introduces several components, including additional buttressing of the NTSF and STSF embankments, the recommencement of Ridgeway operations, the construction and operation of a hydrocyclone pilot plant, mine-related infrastructure upgrades, road and pipeline realignments, extended operating hours for trains at the Cadia Valley Operations dewatering facility, and minor administrative changes.

The NSW Department of Planning, Housing and Infrastructure has recognised the need for further embankment reinforcements to ensure sufficient on-site storage beyond 2028, when Cadia Hill reaches capacity. These reinforcements align with updated Australian standards and guidelines for tailings storage safety.

The modification is expected to increase noise levels by up to 5 dB at four rural residences, primarily owing to embankment construction at the NTSF and STSF. Concerns were raised regarding noise impacts from these activities during evening hours, as well as from night-time train movements at the Cadia Valley Operations dewatering facility.

However, the department considers that Cadia’s proposed mitigation and management measures, along with existing and recommended conditions, will appropriately manage noise impacts.

Cadia general manager Tom Lukeman welcomed the approval, highlighting its role in sustaining Cadia’s economic and social contributions, including employment for 1 800 people, most of whom live in the Orange, Blayney, and Cabonne districts.

“The project has successfully met every step of the NSW environmental assessment requirements and will enable the continuation of safe and efficient mining operations,” Lukeman stated.

“Our team has worked with NSW regulators to ensure a balanced outcome while responding to the community’s feedback.”

The Modification 15 approval was granted on the basis that its impacts are acceptable and that the project is in the public interest. Further, Cadia has committed to limiting ventilation system emissions to a maximum of 50 mg/m³ through emission scrubbing systems.

This decision also enables further upgrades to Cadia’s tailings storage facilities and the implementation of additional infrastructure improvements to enhance efficiency and ensure ongoing safe mining operations.

Lukeman said Cadia was committed to community engagement and investment, stating that between July 2022 and December 2023, the mine contributed $5.98-million to local community programmes, education, and infrastructure.