Geochemistry and Mineralogy of Maastrichtian Coals from the Anambra and Gongola Basins of Nigeria: Implications for Coal Quality, Resource Potential, and Agglomeration Characteristics

Anambra and Gongola basins are part of the sedimentary inland basins in Nigeria characterized by fossil fuels and in response to its present energy problem, Nigeria has shifted its power generating focus to coal. The studied coals were obtained from two localities, namely Ankpa and Maiganga in Kogi and Gombe States, respectively. The coals were investigated to determine its quality in terms of use and resource potential. The coals were analyzed by proximate, ultimate, elemental, mineralogy and scanning electron microscopy-energy dispersive spectrometry analyses. The objectives of the study are to determine the coals cokability, rank, paleoenvironments, hydrocarbon potential, and slagging tendency. The average values of moisture content, ash, volatile matter, and fixed carbon are 5.54%, 16.42%, 48.45%, and 30.71%, respectively, for Ankpa coals, while Maiganga recorded 10.68%, 8.60%, 44.33%, and 36.41%, indicating high volatile sub-bituminous non-coking coals that are optimum for combustion and electric power generation. The Van Krevelen plot based on the H/C vs. O/C showed Type IV kerogen. The XRD results, correlation plots, and Detrital Authigenic Index (DAI) values of 7.49 and 13.49 in Ankpa and Maiganga coals, respectively, indicated that Ankpa coals are enriched in authigenic minerals like quartz, pyrite, and calcite, while kaolinite and quartz were probable detrital minerals in the Maiganga coals. The agglomeration of the coals deduced by Base/Acid (B/A), Silicon ratio (G), Silica/Alumina (S/A), Iron/Calcium (I/C), Carbon/Hydrogen (C/H), and Fixed Carbon/Volatile matter (FC/V) showed weak–medium-strong for the Ankpa coals and strong for Maiganga coals.