OZ Minerals Starts Building Major Mine at Carrapateena

OZ Minerals has started construction at its underground, sub-level cave Carrapateena copper-gold mine in South Australia. Preproduction development costs are expected to be about A$916 million. Production of metal in concentrates over a mine life of 20 years is planned to average 65,000 metric tons per year (mt/y) of copper and 67,000 ounces per year (oz/y) of gold. Commissioning is planned for the fourth quarter of 2019.

Carrapateena’s planned life-of-mine production rate is 4.25 million mt/y of run-of-mine ore. The ore reserve estimate currently stands at 79 million mt at a copper equivalent grade of 2.31%.

OZ can fund Carrapateena development from cash on hand and expected cash flow from its Prominent Hill mine, located about 250 kilometers (km) to the north, without the need for debt, while maintaining its dividend policy.

Construction of enabling infrastructure for Carrapateena began in September, including the accommodation village and airstrip and continuing development of the plant. The “Mining Lease” approval process was ongoing, with state and federal government departments working to an agreed schedule that was expected to see the lease granted in January 2018.

The second phase of construction, subject to Mining Lease approval, is scheduled to begin in the second quarter of 2018 and will include construction of the processing plant and other above-ground infrastructure, installation of the underground materials handling system, and construction of the tailings storage facility, access road, and power line. Development of the mine access decline had reached 2,594 m as of late August, and the conveyor decline had broken through to the box cut.

“Our caving knowledge has been enhanced with recruitment of a number of experienced cave miners into key operational roles — including general management, technical service and mining — and the engagement of caving experts for a revised mining study and mine plan,” said OZ Minerals CEO Andrew Cole.

“There is strong community support for the project. A Native Title Mining Agreement, underpinned by the landmark partnering agreement, is now in place with the Kokatha Aboriginal Corp., following a community meeting at the end of July.”

Major processing steps to produce Carrapateena concentrate will include SAG and ball milling, pebble crushing, and rougher flotation, followed by three stages of cleaning. An internationally saleable concentrate will be produced and trucked about 160 km to Port Augusta on the Spencer Gulf for shipping to customers.

OZ Minerals’ previously announced plans to build a concentrate treatment plant at Port Augusta are now being managed as a separate project, independent of the Carrapateena timeline.

“The concentrate treatment plant continues to offer opportunities to be a strategic differentiator for OZ minerals, with the capacity to upgrade concentrates to 50% to 60% copper with negligible impurities, making them an attractive feedstock for customers throughout the world,” the OZ statement said. “While not needed for Carrapateena, the project potentially offers future upside for both Carrapateena and Prominent Hill in light of the global trend of decreasing concentrate grades and increasing impurities in the copper concentrate market. Therefore, the scope has been expanded to include Prominent Hill concentrate.

“Test work has confirmed the viability of the process, and the focus of current studies is on development and optimization of the various technical options.”

As featured in Womp 2017 Vol 10 - www.womp-int.com