LionOre taking Activox to the stage at Tati (February 07, 2005)

Following success in the demonstration phase, the Activox hydrometallurgical nickel plant at the Tati mine in Botswana will now go into continuous production.

Operator LionOre Mining International (LIM-T) reached a decision to begin commercial production from the plant. Activox, a hydrometallurgical process whose patent is held by LionOre, treats a bulk nickel-copper-cobalt concentrate produced by the Tati mill.

The system consists of an ultra-fine grinding circuit feeding an oxidizing leach circuit, which operates at what are, in hydrometallurgical terms, low pressure and temperature: 1,000 kPa and 110C. The leachate then goes through a conventional solvent extraction system, and the nickel and copper are recovered electrolytically. Cobalt comes off as cobalt carbonate at an intermediate stage.

Trials of Activox at Tati began in May 2004, divided into three campaigns of 10 weeks each. The first two were operated by consulting firm Western Minerals Technology, in which LionOre holds an 80% interest. After the plant was commissioned and the LionOre personnel trained on the system, LionOre took over operation of the plant, with Western’s assistance, for a third milling campaign. With those runs completed, LionOre flew the system solo in a fourth campaign near the end of the year.

The plant recovered 98% of nickel and 90% of copper in the feed, well above design figures. The cathode nickel beat 99.9% purity, and the copper was more than four-nines.

As built, the plant has an 8-tonne-per-day capacity for concentrate feed, producing 0.3 tonne nickel and 0.15 tonne copper. Commercial production, to recover 20,000 tonnes nickel annually, will require a scale-up of about 200 times.

Tati itself had a tough fourth quarter, as unusually heavy rains flooded the Phoenix open-pit nickel mine. In early December 2004, the mine received 157 mm of rain in 36 hours, the heaviest rainfall in the area in 65 years. Flooding blocked access to high-grade material in the bottom of the pit, forcing Tati to get by on lower-grade zones that were still accessible.

Further rains between Jan. 19 and 23 added 182 mm, meaning operations in the lower levels of the pit will not resume before mid-February. Two large production shovels, which could not be used during the flooding, were pulled back for mid-life refits, ahead of schedule.

The Tati mill still produced normal amounts of concentrate during the quarter.