Kasese cobalt project completed

A cobalt recovery plant has been built for Kasese Cobalt Company Limited (KCCL) in south-western Uganda. KCCL is a subsidiary of Banff Resources of Canada which is owned by La Source, the French based mining company controlled by Normandy Mining of Australia and BRGM of France.

The plant is designed to process 10 tonne/h of a pyrite stockpile
containing 1,4 % cobalt, to produce 1 000 tonne/yr of cobalt over the next 11 years. The stockpile originates from the old Kilembe Copper Mine and is situated in the foothills of the Rwenzori Mountains adjacent to the Queen Elizabeth National Park, some 12 km from the mine.

BATEMAN provided design, engineering, procurement and construction management. This included the process design package for cobalt electrowinning as well as the detailed
design and construction of the process plant and utilities, infrastructure and tailings dams. The activities of two other technology consultants engaged on the project were also coordinated. The hydropower station was supplied by another contractor.

The process involves bacterial leaching of the pyrite, neutralisation with limestone to remove acid and iron, removal of copper and nickel as saleable hydroxides, and the purification and recovery of cobalt by solvent extraction and electrowinning. The plant is unique and, so far as is known, is the first to employ bacterial leaching coupled with solvent extraction and electrowinning of cobalt. This project will have a beneficial impact upon the environment in the area, as the treatment of the stockpile will leave a safely contained residue in specially designed dams. The old stockpile has been partially eroded over the years and acidic run-off has caused widespread damage to the surrounding area.

On completion of operations all traces of the plant will be removed and the entire site grassed over. Work on this reimbursable project
commenced in August 1997 and the first cobalt cathode was produced in June 1999. The total cost of the project was about US$120M, of which BATEMAN was responsible for approximately 60 %. An office was set up in Kampala to facilitate communications and cope with the logistics of supplying this remote site.

Materials had to be shipped via Mombasa and sent by road through Kenya and Uganda, a distance of some 1 600 km over indifferent roads often affected by heavy rains. Goods could also be flown in via Entebbe, a distance by road of 500 km from site. Clearing goods through customs was a challenge. Several dangers were prevalent in the surrounding countryside. Foremost
was malaria, with the strictest observance of preventative and
prophylactic measures being necessary. Rebel activity was a constant threat with consequent curfews and proclamations
of restricted areas.

More information can be provided by Nick Haywood, Project
Manager, at nhaywood@bmi.co.za or Graham Fisher, Lead Process Engineer, at gfisher@bmi.co.za.

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