WINDHOEK – A prefeasibility study is underway in //Kharas Region to analyse the technical and commercial viability of what is believed to be one of the largest copper porphyry deposits, or copper orebodies, in Africa. According to a recently completed preliminary economic assessment, the deposits have potential to produce a net present value of N$9 billion and a pre-tax internal rate of return of 30.4 percent at US$3-per-pound copper.
The deposits are at what is now being called the Haib mine, on the mountains that edge the Orange River, 8 kilometres from the river that demarcate borders with South Africa. Canadian listed Deep South Resources owns the Haib Minerals, with Teck Resources owning 35 percent.
“Deep-South is carrying out a pre-feasibility study for the mine to analyse the technical and economic viability of the project. The expected mine life is 55 years when mined at the rate of 8.5 million tonnes per annum (Mtpa),” the company had said in its notice to investors.
“The Haib deposit is the oldest porphyry deposit in the world, which hosts easily identifiable porphyry veins and alteration. It is part of the Richtersveld geological sub-province, located within the Namaqua-Natal Province in the northern corner of South Africa,” the company said.
The deposit, discovered in the 1950’s, has seen over 50,000 metres of drilling in the 1970’s by companies such as Rio Tinto and Falconbridge Ltd, the company said.
So far, estimates are that the mineral reserves in the Haib mine are 456.9 million tonnes (Mt) grading 0.31 percent copper. The inferred resources are estimated to be 342.4Mt grading 0.29 percent copper.
The mine is set to be an open-pit with the method of mining including drill and blast activities.
The ore will be processed using a bio-assisted heap leach method, which includes a three-stage crushing process to reduce to a size of 6mm or less and then placed on a leach pad. Bacteria mixed with sulphuric acid will be added to the leach pad to facilitate faster oxidation of the ore.
“The oxidised ore will produce copper loaded extractants, which will be stripped to produce copper sulphate solution. Electrowining will be used to separate copper from the copper sulphate solution,” the company said. Water for the operation is likely to be sourced from the Orange River through a 15-kilometre pipeline, and electricity sourced from an 85-kilometre link to the national power grid.