MESMEG / Department of Mining and Environmental Geology / The future of energy in South Africa depends on coal as it is one of the cheapest and most affordable sources of energy; however, some of the coal is uneconomical to mine due to the thickness and depth of the coal seams. For many years the coal resources of the Soutpansberg Coalfield remained untapped and limitedly researched and with the coal resources running out in the other coalfields, the Soutpansberg Coalfield remained the bright coalfield of tomorrow in South Africa. Coal seams in the Soutpansberg Coalfield occur within the Madzaringwe Formation. Three coal basins have been identified in this coalfield, are the Venda-Pafuri, Tshipise and Mopane. Sedimentological basin analysis of the coal stratigraphy and characterisation of the Soutpansberg Coalfield in the Makhado area, Limpopo Province was investigated within the farms of Rissik, Fannie, Duel, and Lurkin. The main purpose of the study was to establish the variation of the coal stratigraphy and how coal influenced the stratigraphy within the area. Fieldwork involved core logging and core sampling from the different farms within the Makhado coal area, while laboratory work included petrographic studies, investigation of the physical and chemical properties of coal. Core logging revealed the occurrence of coal zones where coal seams were intercalating with mudstones, but rarely with siltstone that formed the footwall of coal. Rarely was coal intruded by dolerite dyke as was the case along borehole W6610001. Core logging further revealed the sedimentary structures in the lithologies and the depth at which different lithologies were intersected. From these sedimentary structures, the environment of coal deposition was deduced supported by the geochemical analysis of major oxides and trace elements. Correlation of boreholes along the strike showed that the shale and mudrock were the predominant rocks within the coal horizon leading to the conclusion that these were the coal host rocks. Whole rock geochemical analysis was undertaken, using X-Ray Fluorescence Spectroscopy in order to establish the rock types and their trace element contents. The collected samples were analysed at the University of Venda, Department of Mining and Environmental Geology Laboratory, Siza Coal Services in Secunda and Council for Geoscience. The study indicated that the coal seams of the Soutpansberg Coalfield were deposited within the floodplain of a mixed-load fluvio-deltaic (fluvial and braided) systems. This sedimentary channel has been the major influence on the development of the coal seams. Locational changes in sedimentary facies above and below the coal seams within the study area has caused variations in the rates of compaction and subsidence which influenced the coal basin morphology and the coalification pattern. These two parameters (variations in the rates of compaction and subsidence) controlled the coal quality parameters, and coal seam thickness as well as the coal composition. The study confirmed that coal quality and thickness vary markedly from place to place in this coalfield due to varying local depositional environments. Most of the drill holes intersected mainly 3 coal seams, although in some cases either 2 or 5 seams were intersected. The thickest coal seam (borehole F578002) was 8 m. It was concluded that the coal was sub-bituminous to bituminous coal rank class (medium-volatile bituminous coal rank class). The coal had low moisture content ranging from 0.7-0.8%, and ash content ranging from 21.4-32%. The fixed carbon and volatile matter values of the coal samples ranged from 42.5 to 50.4% and from 25.2 to 27.4% respectively. The carbon and hydrogen were the main principal combustible elements in coal, however; carbon is the predominant one based on weight, constituting about 5.3% (the lowest) to 70.3% (highest) of the total. Due to the nature and thickness of the coal seams we conclude that this coal was economical to be mined and can be used for electricity generation and in cement grinding plants. A graph of coal gas concentrations over combustion time showed that methane (CH4) and carbon dioxide (CO2) had high gas concentrations, amounting to 1.75% and 1.70% respectively. / NRF

MESMEG / Department of Mining and Environmental Geology / The Mushithe coal occurrence is situated approximately 16 km west of the Tshikondeni coal mine in the Tshipise-Pafuri sub-basin of the Soutpansberg coalfield in South Africa. The Soutpansberg Coalfield has received comparatively less attention compared to other more notable South African coalfields. There is as a consequence very limited information in the public domain applicable to the geology as well as quality of coal in this coalfield, as a result there is no known study focused exclusively on the Mushithe coal occurrence. The aim of the study was to conduct detailed geological mapping of the Mushithe Deposit so as to ascertain the geological environment and petrological characteristics of rocks within the area. Further work involved coal sampling and analysis in order to establish coal quality and its physical and chemical characteristics. Samples were collected using geological field mapping and channel sampling. Nine coal samples were collected from the coalbed and host rock, exposed along the Mbodi River, during geological field mapping using channel sampling. Furthermore, 92 rock samples were collected during geological field mapping of which 10 representative samples were selected for further analysis. X-ray fluorescence spectrometry was conducted on all selected samples. Proximate analysis and ultimate analyses, and calorimetry tests were undertaken on coal samples. Three samples were selected based on calorific value for maceral identification, mineral analyses and vitrinite reflectance using petrographic study. Detailed geological mapping of the area around the Mushithe coal occurrence showed the geological setting of coal in this area. The following lithologies were identified in the study area: sandstone, mudstone, ironstone, calcrete, shale, quartzite, quartz vein with a general strike direction to the north-east. The host rocks including coal were intruded by dolerite dykes and this resulted in the devolatilization of coal. The current study concluded that the Mushithe coal was formed in a wet swampy environment. This has been confirmed based on tissue preservation index (1.69) and gelification index (2.35). Coal rank ranged from bituminous Rank C- B according to United Nations Economic Commission for Europe Coal Classification (UNECE) and samples were characterised by high ash (27.90%), high moisture (10.47%) and low sulphur (0.24%). Furthermore, coal was graded below grade D based on classification for use by ESKOM which consider any calorific value below 24.5 MJ/kg to be in this category. The coal is vitrinite rich (77.75 vol%) and low in Inertinite (22.25 vol%) and devoid of Liptinite and pseudovitrinite, thus it is of good coking quality. Geochemical analysis revealed that the coal was enriched in TiO2 and Fe2O3 which was corroborated by the mineral matter which was mostly clay and pyrite. Comparatively, coal quality analysis revealed the calorific value of 14.26 MJ/kg and vitrinite reflectance between 0.94 %ROV to 1 %ROV which was less than that of the Tshikondeni Deposit but greater than that at Waterberg coalfield. The study recommends further detailed exploration of coal in the area, applying such techniques such as geophysical exploration and borehole drilling leading to resource evaluation. Further studies are recommended to provide a better interpretation of the depositional environment of coal at Mushithe as well as the effect of devolatilaziton by a dolerite dyke. / NRF