Water is one of the focus subjects in the July issue of the magazine. Typical of what is required in African countries and places like Chile and Australia, Sinclair Knight Merz (SKM), has an EPCM contract for Oz Minerals to undertake upgrade works for the water supply well field at its Prominent Hill mine in South Australia. These works are required to ensure longterm water supply security for the mine for a range of mill throughput rates, including the re-development of a number of production wells, the drilling of an additional (16th) production well, and connecting that well into the water supply system, and the investigation of the potential to expand the well field at some stage in the future.

The contract also includes optimising the well field to include variable speed drives at each of the production wells and upgrading well headworks, electrical controls and the operating system (including SCADA). The Prominent Hill Copper/Gold mine is located in the far north of South Australia. The mill currently operates at around 1,200 t/h ore throughput. SKM has been working with Oz Minerals at Prominent Hill on water supply-related projects since 2005. More recently, SKM has continued to provide support in preparing environmental compliance reports and operating the water supply well field. Early studies centred on hydrogeological aspects of the project and involved identifying a groundwater resource for the mine, supervising the construction of a 22 million litre/d wellfield located between 40 and 80 km from the mine, and assisting with gaining regulatory approvals and water licences.

The wellfield, which was commissioned in early 2009, presently comprises 15 production wells that draw water from depths of up to 500 m. Hillgrove Resources’ Kanmantoo copper mine is another interesting Australia project. The mine has signed a long term contract with the District Council of Mount Barker (DCMB) for the supply of recycled treated waste water for use as process water at the mine, 55 km east of Adelaide. The innovative water contract will generate a revenue stream and cost savings for the DCMB and, importantly, it also eliminates a new draw on the water resources of the Murray River system. “From the community’s point of view it results in significant benefits to local flora, fauna and the water quality of Mt. Barker Creek. At the same time, the contract allows the District Council to plan for population growth in the Adelaide Hills without the constraint of waste water issues,” Dean Brown, Hillgrove Chairman, said.

The contract commits Hillgrove to design and build a 16 km buried pipeline from the DCMB’s Brown Dam to the mine site. Once completed, the infrastructure will vest with DCMB. The term of the water supply contract is five years with a three-year option and the right to renew the contract every three years thereafter while the mine operates. DCMB has allocated up to 750 million litres annually to Kanmantoo. The Kanmantoo mine’s daily raw water requirement is forecast to be 2.1 million litres, which can be satisfied from the contract with DCMB for most of the year. Kanmantoo can also source water from the SA Water Scheme, existing ground water bores, water inflows into the open pit and seasonal water harvesting.