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).

Despite the discovery of Gamsberg zinc deposit in 1972, the ore body continues to be South Africa’s greatest unexploited base metal resource. Regardless of its size, the low zinc and high manganese content of the sphalerite combined with the low zinc price prohibits the development of the deposit. The high manganese content of the sphalerite makes it unsuitable for processing by conventional methods i.e. roasting, leaching/ solvent extraction and/or electrowinning (McClung & Viljoen, 2011). The ore body has two distinct ore types, namely pelitic and garnetmagnetite ore. The pelitic ore is characterized by a high Fe-suphide content whilst the garnet-magnetite ore have higher levels of ........

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

54MT reserves have been added post completion of Feasibility study for expansion which can result in additional 200ktpa MIC production over and above current production. The mine design and the new reserve statement was completed with the Resource to Reserve conversion as scheduled. The project is currently split into two distinctive sections, one focused on increasing the mining to 9 MTPA and second focused on construction of a duplicate concentrator plant, effectively doubling the capacity.

The final open pit is expected to cover an area of 600 ha, with a final depth of 650 m, and a width and length of 2 220 m and 2 700 m respectively.

Loading and hauling of ore and overburden is performed in the pit using a fleet of large capacity shovels, loaders, excavators, haul trucks and other service equipment. The ore is hauled to the primary crusher and overburden to the waste rock dump using large capacity haul trucks (typically between 220 tonne (t) and 300 t capacity).

The primary crusher is located adjacent to the open pit on a flat point of the V-cut access road along the northern slope of the inselberg. The crushed ore is transported from the primary crusher and the Run of Mine (ROM) stockpile to the processing plant via a conveyor system.

An estimated 1.5 billion tonnes of waste r ........

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