OZ Minerals to begin Carrapateena block cave expansion

OZ Minerals managing director Andrew Cole said decline early works were set to begin in the last quarter of this year, with the expansion now integrated into the operations plan.

The decision follows a pre-feasibility study on block cave expansion last year, proving that converting the lower portion of the sub level cave to a series of block caves will significantly increase Carrapateena’s reserve and mine life.

The expansion is also envisaged to increase production to 12 million tonnes a year, delivering around 110,000-120,000 tonnes of copper and 110,000-120,000 ounces of gold a year.

“The integration and acceleration of the block cave expansion allows progressive de-risking of the Carrapateena province in its sub level cave ramp-up to 4.7-5 million tonnes a year from 2023 and transition from sub level cave to block cave, while preserving optionality at future major capital milestone decisions over the coming years,” Cole said.

“The accelerated program could bring forward commencement of block cave production by circa six months.”

The news of the board approval came as Oz Minerals declared its achievement of its copper guidance for the sixth consecutive year.

The company produced 27,632 tonnes of copper at Carrapateena and 61,375 tonnes at Prominent Hill, also in South Australia, during the 2020 fiscal year.

Oz Minerals completed its ramp up phase at Carrapateena six months ahead of schedule, with the mine set to be cashflow positive this year.

It is also committed to invest in future decline development at Prominent Hill to increasing mining rates further from 2022 to 4-5 million tonnes a year.

Oz Minerals expects to make its final investment decision for Prominent Hill mid this year.