Key lithologies of the Mines Subgroup at the MMG Kinsevere Mine, Katanga Province, Democratic Republic of Congo - The lowest member of the Mines Subgroup at Kinsevere is the Grey R.A.T. (Roches Argilo-Talqueuses - lower left), a grey, largely structureless dolomitic silt to sand rock, which may be brecciated, as in this image. This is overlain by thinly developed D.Strat. (Dolomie stratifiées - second from left) which represents the Lower Orebody position, and comprises a massive to crudely laminated suite of silicified, impure dolomite, followed by the R.S.F. (Roche Siliceuses Feuilletées - third from left), a thinly and regularly laminated silicified dolomite. The R.S.C. (Roches Siliceuses Cellulaires), normally found above the R.S.F., representing a stromatolitic reefal facies, is absent at Kinsevere. Instead the overlying S.D. (Schistes Dolomitiques - upper image) follows the R.S.F. At Kinsevere, the S.D. is thicker than normal, and is characterised by well bedded, black, carbonaceous, fine-grained micritic cemented clastics rocks, and hosts the main Upper Orebody. This unit also carries pyritic intervals which produce sulphur blooms on exposure to the atmosphere (see upper image). The next unit above the main ore, is the C.M.N. (Calcaire á Minerai Noir - second from right), which is slightly coarser and more dolomitic than the S.D., and also hosts part of the Upper Orebody. The upper margin of the Mines Subgroup is marked by the Heterogeneous Breccia, which at Kinsevere has a matrix rich in kaolinite and rock flour, enclosing clasts of a range of Mines Subgroup lithologies. Photographs by Mike Porter.