Petrographic consideration of the impact of the Tshipise Fault on coal quality in the Soutpansberg Coalfield, South Africa

M.Sc. (Geology)Abstract: The Soutpansberg Coalfield is hosted in the Karoo Basin in the Limpopo Province of South Africa. The basis of this research is to understand coal quality, coal composition, petrographic variations, and depositional environments, of coal samples from the Soutpansberg Coalfield. The Soutpansberg coals are preserved within extensive horst and graben systems and faults have exerted major structural controls on the geology. There are three major faults, the Klein Tshipise, Tshipise, and Bosbokpoort Faults. On the southern side of the Tshipise Fault, which is ENE-SWS trending, the coal exhibits higher reflectance values and coking properties compared to the coals occurring on the northern side of the Tshipise Fault, where lower reflectance values and limited coking properties occur. Thirty five samples were collected across the coalfields of Limpopo, with the focus being the Makhado area either side of the Tshipise Fault. The coal samples were sampled from the Madzaringwe Formation in the Soutpansberg and Limpopo Coalfields. Chemical analyses (including proximate analyses, CV, and total sulphur), Free Swelling Index, petrographic analyses (maceral point, vitrinite reflectance and abnormal condition), and mineral analyses (XRD, SEM, EMPA) were conducted on the samples. The petrographic analyses were carried out using Zeiss Axio Imager M2M retrofitted with Hilgers Diskus Fossil software, at a magnification of x500 under oil immersion. The samples were scanned automatically and analysed offline using Fossil Student. According to the UNECE classification, the rank of the coal north of the Tshipise Fault ranged from bituminous medium Rank C - A coal and coal samples south of the Tshipise Fault ranged from medium rank C to A. Most coal samples were characterised by relatively high ash, total sulphur, and volatile matter contents, and low moisture and calorific values. High FSI number was found to be associated with samples that had high volatile matter, lower ash content and higher calorific values. The maceral analysis indicated that the coal horizons are rich in vitrinite, with low inertinite and very low liptinite contents, considered to be characteristic of the Soutpansberg coals. Pseudovitrinite was observed, which is not a good indicator for coking properties..