BASE METALS SPECIAL — Sanyati producing copper

The Sanyati operation in Zimbabwe produced its first cathode copper late last year, on budget and on time.

The open-pit mine is owned 75% by London-listed Reunion Mining, with the balance held by Zimbabwe Mining Development.

Proven and probable oxide reserves total 5.8 million tonnes at a grade of 1.1% copper and 1.12% zinc, plus values of cobalt and manganese. The project also contains sulphide resources, last reported at 14.1 million tonnes at 1.25% copper, 3.22% zinc and 0.96% lead.

Sanyati is designed to produce 5,000 tonnes of London Metals Exchange Grade A cathode copper each year, over a mine life of 8-10 years.

At the moment, copper alone is being recovered, by means of solvent extraction-electrowinning. However, test work indicates that zinc, cobalt and manganese could be economically recovered. A development decision awaits the results of a full pilot operation to test the new process technology.

Reunion’s metallurgical test work has also focused on exploiting the sulphide resource through either pressure leaching or the more conventional roast-leach process route. The study found that producing metals on site was a more favorable option than producing sulphide concentrates.

Reunion has numerous gold, base metal and diamond projects in Africa, and it recently entered an agreement allowing it to acquire up to a 60% interest in the Skorpion zinc deposit in southern Namibia.

Skorpion hosts a measured and indicated resource of 8.3 million tonnes averaging 10.9% zinc, amenable to open-pit mining. The deposit was discovered in the late 1970s and metallurgical work done since then has been focused on finding a viable treatment process.

Reunion will examine the possibility of heap-leaching, namely a sulphurous acid-leach similar to that employed at Sanyati.