The Broken Hill deposits form part of the Bushmanland Group which is a volcano- sedimentary sequence that hosts ore deposits (Reid et al., 1997). This group has metapelitic rocks that are CaNa-Mg depleted. The group’s ore body is divided into two types: a pyrrhotite-galena-sphaleritechalcopyrite ore hosted by quartz-garnet-rich gangue (Black Mountain and Broken Hill) and a pyrite-pyrrhotite-sphalerite ore hosted by quartz- biotite-sillimanite gangue (Big Syncline and Gamsberg). The principal ore minerals are sphalerite, galena and chalcopyrite with garnet and apatite being minor constituents. Barite horizons occur as lateral equivalents of the sulphide ores at Black Mountain and Gamsberg and calcitic marble bands are associated with the Big Syncline and Gamsberg (Moore et al., 1990).

Gamsberg is one of the largest known, undeveloped zinc orebodies in the world and comprises an open pit mine and a dedicated processing plant.

Depending on market conditions, Phase 2 of Gamsberg could start as early as completion of Phase 1. It is envisaged that at least a portion of Gamsberg’s zinc-in-concentrate production will be trucked to the Skorpion Zinc refinery in Namibia for refining.

While the Skorpion refinery is currently configured to refine Skorpion’s oxide ore, it will be converted to also take sulphide concentrate from Gamsberg once Skorpion’s own oxide reserves are exhausted. At some point in the future, depending on market conditions and other factors, Gamsberg june warrant its own refinery.