The key Mines Subgroup lithologies at Tenke-Fungurume, Katanga Province, DRC. - The host succession at Tenke-Fungurume, is as follows, from the base:
R.A.T. Lilas or Roches Argilo-Talqueuses Lilas (upper left) - the lowest unit of the Roan Group, always with a structural base, overlying younger Kundelungu Group rocks. A lilac to red, largely structureless, dolomitic to talcose and argillaceous silt to sandstone that may be >200 m thick. This example is outcropping and weathered from the Mwadinkomba deposit area.
Grey R.A.T. or Roches Argilo-Talqueuses Grises. Two images:
• (upper row, second from left) - 2 to 5 m of white, bleached variety of the R.A.T. Lilas. This sample is weathered, outcropping adjacent to the Mwadinkomba deposit.
• (upper row, third from left) - a grey, reduced specimen, which is brecciated, and less weathered than the previous sample. It is from the oxide zone in the upper benches of the Kwatebala pit.
R.S.F. or Roche Siliceuses Feuilletées (laminated siliceous rock) - a 10 to 15 m thick, thinly and regularly laminated silicified algal dolomite, which, with the intervening 2 to 7 m thick D.Strat. (not represented in this collage), hosts the Lower Orebody. Three images:
• (upper row, second from right) - a sample from outcrop adjacent to the Mwadinkomba deposit.
• (upper row, right) - this sample is from the oxide zone in the upper benches of the Kwatebala pit.
• (lower row, left) - this sample contains high grade mineralisation from the oxide zone in the Tenke area and is less weathered than the previous two exposures.
R.S.C. or Roches Siliceuses Cellulaires. Two images:
• (lower row, second from left) - massive, sometimes cavernous, strongly silicified, stromatolitic dolomite, which is 20 to 35 m thick and is generally barren in the hypogene zone, but may contain rich supergene ore. This massive, originally porous reefal facies rock, separates the laminated, carbonaceous rocks of the R.S.F. and S.D.B. that host the Lower and Upper orebodies. This sample is unweathered from the primary zone deeper in the Kwatebala pit.
• (lower row, third from left) - this sample is from near the surface in the Kwatebala pit. It exhibits the siliceous-cellular textures from dissolution of carbonates from which its name is derived.
S.D.B. or Schistes Dolomitiques Basal (lower row, second from right) - which immediately overlies the R.S.C. and hosts the Upper Orebody. It comprises thin, platy, laminar, sericitic to hematitic, dolomitic siltstone and shale. This sample is from the oxide zone in the upper benches of the Kwatebala pit.
S.D.S. or Schistes Dolomitiques Superieures (lower row, second from right) - a more sandy suite of dolomite and dolomitic siltstone occurring above the Upper Orebody. This sample is also from the upper benches of the Kwatebala pit.
Photographs by Mike Porter.