Name of the Project
Prominent Hill copper/gold/silver mine expansion.

Location
Gawler Craton, in South Australia.

Project Owner/s
Copper/gold miner OZ Minerals.

Project Description
An update on the Prominent Hill expansion study has shown that the installation of a 1 360 m, 7.5-m-diameter vertical shaft is technically and economically feasible, with capital investment consistent across the interim and strengthened cases.

Construction of the shaft is at this stage assumed to be a conventional blind sink.

A shaft will provide access to the deeper orebody beneath the current ore reserves boundary and exploration opportunities beyond the current mineral resource limits.

The update is based on a conservative interim case containing only one-third of the total Prominent Hill inferred resource of 59-million tonnes outside the current life-of-mine plan.

The project has total mineral resources of 150-million tonnes grading 0.9% copper, 0.7 g/t gold and 2 g/t silver. Total proven and probable reserves are estimated at 56-million tonnes grading 0.9% copper, 0.7 g/t gold and 2 g/t silver.

Shaft hoisting is the key enabler that will facilitate increased mine production. The company approved the construction of a hoisting shaft at the mine in August 2021. The Wira shaft would extend the mine life from the current nine years to 15 years, until 2036, at six-million tonnes a year.

The miner has since reported that project optimisation works have identified the opportunity to increase the hoisting shaft capacity by 8%, from six-million tonnes a year to 6.5-million tonnes a year.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
Not stated.

Capital Expenditure
A$600-million.

Planned Start/End Date
The Wira shaft mine expansion project was approved in August 2021, with works well progressed and scheduled for completion in 2024.

Latest Developments
OZ Minerals has announced a decision to increase the hoisting shaft capacity at Prominent Hill from six-million tonnes a year to 6.5-million tonnes a year for an additional A$2-million, with the increased capital to be absorbed within the approved A$600-million budget.

The change in design includes an upgrade to the shaft winder motor, enlarged skips and upgrades to the material handling system which, in turn, provide optionality to increase yearly mine production rates.

Work is under way to assess whether underground mining rates can be increased to fully use the increased 6.5-million-tonne-a-year hoisting-shaft capacity. An update to this assessment, including any operating cost-benefit, is expected in the second half of 2022.

Key Contracts, Suppliers and Consultants
AECOM Australia, AGC Consulting, AMC Consultants, Ausenco, BBE Consulting, Beck Engineering Australasia, Boart Longyear, Byrnecut, Coffey, Convergen, D Why, EMM, Emtek, Golders, John Thompson Inclusive, Keaveney Consulting, Land and Water Consulting, Loesche, MCA, Mine Fill Services, Minset, More Space for Light, Newcrest Telfer Operations, Newmont Tanami Operations, Noble Environs, Pete Holliday, Redpath, Pells Sullivan Meynink, RUC, SAGE Automation, SRK Consulting, Stantec International Consulting, Strategy Focused Innovation, Woodgrove and Xylem Water Solutions (expansion study); and Hatch, IA Engineering, Optiro, SimSAGe, Stantec International Consulting, Strategy Focused Innovation and SRK International (peer review).

Contact Details for Project Information
OZ Minerals, tel +61 8 8229 6600 or email info@ozminerals.com.