The Skorpion zinc project

The feasibility study for the Skorpion zinc project about 75 km north-east of Oranjemund in south-western Namibia has been completed successfully. The principal conclusions confirm that Skorpion could rank as one of the largest integrated zinc mines and refineries in the world and that it has the potential to be one of the lowest cost producers in the industry.

Completion of the study enabled Reunion Mining PLC to earn a 60 % interest in the deposit from Erongo Mining and Exploration Co. Ltd, a subsidiary of the Anglo American Corporation of South Africa (AAC). AAC has subsequently purchased Reunion Mining PLC and now controls 100 % of the Skorpion zinc project.

BATEMAN’s role in the study included design engineering and cost estimation services for the metallurgical plant and, assisted by various subcontractors, investigating the local infrastructure required. It also assisted Reunion to compile the feasibility study report. Reunion placed a multidisciplinary team of experienced project engineers in the BATEMAN offices under the leadership of Norman Green to provide guidance and coordinate the efforts of the BATEMAN team and other parties involved in the study.

The mine will extract 1,5M t/yr of ore containing an average of slightly more than 10 % zinc from an open pit having a waste-to-ore ratio of 2,63:1. The zinc occurs in an unusual suite of minerals in an oxidised state amenable to direct atmospheric leaching. The ore will be crushed, homogenised and milled to give a consistent product.

At the refinery this product will be leached with acid in agitated tanks, neutralised to precipitate certain impurities and then filtered to remove both precipitate and solid residue. The clarified liquor will be purified by solvent extraction. The zinc will then be electrolytically plated onto aluminium cathodes in the cellhouse and periodically stripped from the cathodes before being melted and cast as ingots suitable for export. Tecnicas Reunidas of Spain and Union Miniere of Belgium respectively provided the technology for the solvent extraction and electrowinning processes and will provide the process guarantees.

The output from the refinery will be 150 000 t/yr of special high grade (SHG) zinc. The mine will have a life of about 14 years, assuming no further ore is discovered in the region, but the refinery may operate on a toll basis thereafter.

Capital and operating costs were estimated to an accuracy of +/- 10 % and 90 % of all costs are based on supplier quotations. Total capital costs are expected to be approximately US$279M.

Environmental considerations were a high priority and the environmental impact assessment, completed to international standards, was approved by the Namibian authorities.

The feasibility study was technically audited on an ongoing basis by SRK Consulting, a leading mineral industry consultancy. The detailed financial model for the project was audited by KPMG.

Kindly contact Steve Burks, BATEMAN Study Leader, on +27-11-899-2756 or email basemetals@batemanengineering.com

VIEW PDF