Sediment Hosted Copper

The Zambian Copper Belt and the Cupriferous Arc of the neighbouring Democratic Republic of Congo (DRC) closely coincide with a complex structural zone, the Lufilian Arc, which is normal to the NE-SW trend of, and near the NE extremity of, the elongate, 2000 km long Damaran-Katangan belt.

Within the two belts there are some 7 major and 25 minor stratabound deposits. The larger orebodies range from 90 to 580 mt @ 2.4 to 3.6% Cu. Between 1930 and 1987 some 24 million tonnes of copper metal was produced from 1070 mt of ore averaging 2.71% Cu and containing 29 mt Cu. The total mined ore plus reserves/resources has been calculated at 3000 mt @ 2.9% Cu.

The ore deposits of Copper Belt are interpreted to lie within coarse silici-clastics.  Some 65% of the mineralisation lies within a finer 0 to 100 m thick unit of generally carbonaceous argillites, carbonatic argillites and interbedded arenites (the Ore Formation) within the coarser clastic succession. A further 25% lies within coarser footwall clastics and 10% within the coarse hangingwall clastics. Lithologically 60% of the ore is hosted by argillites and 40% in arkose, quartzites and conglomerates

The Belt comprises two NW-SE trending parallel lines of Cu mineralisation some 20 km apart, separated by the Palaeo-Proterozoic basement gneisses, granitoids and schists, and Meso-Proterozoic conglomerates, quartzites and granitoids that make up the Kafue Anticline. The majority of the deposits are in the SW band.

Each of these two belts is 5 to 20 km wide and up to 150 km long. The ore grade mineralisation however tends to occupy a linear, often more structurally complex band up to 2 km wide on the SW limb, interrupted by narrow barren gaps and cross folded anticlinal basement cores.