The Guelb Moghrein Copper-gold Project Mauritania Metallurgical Process Selection

Oxide copper was discovered in 1946 at Guelb Moghrein. Early work culminated in the construction in 1970, by a consortium headed by the Anglo American group, of a project producing copper concentrates from 1,000,000 tonnes per annum of oxide ore. The process used was the TORCO (Treatment Of Refractory Copper Ores) process, which reduced oxide copper minerals to elemental copper by roasting in fluidised beds at 800°C with salt and coal. The roaster product was then floated to yield a high grade smelter concentrate, which was exported. The project closed in 1976, due to low copper prices and increased energy prices, leaving an open pit, the old TORCO plant, a water pipeline, and more than 2,000,000 tonnes of tail­ings, which contained remnant copper, as well as an average of 3 git of gold. After several attempts to recommence operations at Akjoujt, recovery of gold from the old TORCO tailings was started in 1992 by a joint venture company known as MORAK (Mines d'Or d'Akjoujt). This company comprises General Gold Resources N.L. of Australia, who are the managing partner, SAMlN (La Societe Arabe des Mines d'Inchiri) and the International Finance Corporation. Because the tailings are high in copper (0.1-0.3% Cu), the project used the 'Hunt' process, which uses a combination of cyanide and ammonia to leach gold while suppressing copper extraction. The gold is recovered from leach liquor by carbon absorption.