OZ Minerals has decided to increase the hoisting shaft capacity under construction at the Prominent Hill gold mine to 6.5 million tonnes per annum (Mtpa), up from the previous 6Mtpa.
Design alterations include an upgrade to the shaft winder motor, enlarged skips and upgrades to the material-handling system which, in turn, provide the option to increase annual mine production rates.
The project scope change will add an additional $2 million with the increased capital, which will be absorbed within the approved $600 million budget.
Prominent Hill is a major copper, silver and gold mine in north-west South Australia, approximately 130km south-east of Coober Pedy.
Work is underway to assess whether underground mining rates can be increased to fully utilise the increased 6.5Mtpa hoisting shaft capacity.
An update to this assessment, including any operating cost benefit, is expected in H2 2022.
OZ Minerals managing director and chief operating officer Andrew Cole said the company was looking forward to the productive future at Prominent Hill, with the Wira shaft mine expansion enabling access to new potential prospects.
“Our agile approach to project delivery encourages our teams to constantly look for opportunities to improve stakeholder value,” he said.
“This is another example of our teams taking an opportunity mindset and identifying and pursuing potential highly value accretive opportunities.
“Construction of the hoisting shaft at Prominent Hill extends the mine life, lowers operating cost, reduces operational risk and lowers emissions intensity compared to the current trucking operation.
“The Prominent Hill team is also continuing the drilling of the exploration targets at Walawuru and Papa. These shallow targets represent further upside potential for Prominent Hill as they are potentially accessible via a trucking operation simultaneously to the current trucking operation and future shaft operation.”
The Wira Shaft mine expansion project was approved in August 2021, with works well progressed and scheduled for completion in 2024.
In August, OZ Minerals was approved to construct a new hoisting shaft at Prominent Hill, adding four years to the mine’s life for a cost of $600 million.
The Wira shaft will allow the mine to operate until 2036 at around six million tonnes per annum.