COPPER: Deep-south project in Namibia
The Haib Copper project hosts a resource of 850 million tonnes at a grade of 0.31% Cu. In 2003, the previous owners of the project ran bio assisted leaching tests with Mintek. Mintek is a leader in hydro-metallurgy and leaching technologies especially in bio-assisted technologies. They had copper recoveries up to 95% – exceptional results. When Deep South took on the project, they completed a PEA using similar bio assisted technologies, and found that bio-assisted leaching, when used in combination with x-ray sorting and a particular grinding approach, to be an effective low-cost method of mineral extraction. The Capex for a 8.5 MTPA production rate is $200 million and the Opex sits at US $1.41 per lbs of copper.
Haib Copper is a large tonnage – low grade copper-molybdenum porphyry deposit, located in the Karas Region of Southern Namibia. Certain characteristics, including the nature of the ore and the geographic location of the project have made it amenable to bio assisted heap leaching. The application of bio assisted heap leaching, in combination with several other ore processing technologies, has enabled Deep South to transform a low-grade deposit into an economically viable mining project.
There are several features that make the ore at Haib so amenable to heap leaching. The most significant is that that mineralogy is very simple and clean; chalcopyrite contains 98.5% of the copper and there are no deleterious materials. Pyrite is also important at 5.16 % of the ore treated. Pyrite generates heat and sulphuric acid while leaching. Heat is important to keep the leaching kinetics active. The recent developments in heap leaching technology have made it particularly suited to Haib ore.
