Physicochemical Characterization of Shela Coal from the Kindo-didaye Area, Southern Ethiopia: Implications for Beneficiation and Sustainable Utilization

The Shela coal occurrence in the Kindo-Didaye area of southern Ethiopia is a coal-bearing locality for which deposit-scale information on physicochemical quality and processing requirements remains limited. This study evaluates the proximate composition, calorific value, sulfur content, and Hardgrove Grindability Index of five coal samples collected from exposed coal seams. Moisture, volatile matter, ash, and fixed carbon contents were 1.21–1.99%, 15.45–26.37%, 28.19–71.26%, and 11.21–44.23%, respectively. Gross calorific values ranged from 2388.02 to 9801.32 Btu/lb (1326.68–5445.18 kcal/kg), sulfur from <0.02 to 2.93%, and HGI from 53.6 to 66.0. Samples S2 and S4 contained substantially less ash and higher fixed carbon and calorific value than S1, S3, and S5, demonstrating strong within-occurrence variability. Ash is the principal quality constraint in several samples, whereas the sulfur concentration in S2 requires particular attention during utilization. The calorific-value range provides a preliminary indication of rank variability, but definitive ASTM D388 rank assignment should not be made from the available data alone because the required mineral-matter-free and basis conversions were not fully established. The results support selective mining, additional washability and mineralogical investigation, and targeted beneficiation before industrial utilization. The study provides a baseline for sustainable evaluation of the Shela coal resource by linking coal quality, processing requirements, energy value, and environmental considerations.