Kontrol Fasies dan Lingkungan Pengendapan terhadap Kualitas Batubara Formasi Warukin di Daerah Haruai, Tabalong, Kalimantan Selatan

Kontrol Fasies dan Lingkungan Pengendapan (Nodyka Elkawi Hawinu, Muhammad Fatih Qodri, Andre Patriot Tampubolon)

Abstract

Coal deposits of the Warukin Formation in South Kalimantan developed within a complex deltaic system, where variations in facies and depositional environments play a major role in controlling the distribution and quality of coal seams. Understanding the relationship between lithofacies characteristics, depositional settings, and coal quality parameters is fundamental for geological interpretation of coal-bearing formations. The analysis was based on borehole log data (gamma-ray and density) and core descriptions to identify facies and depositional environments. The interpretation reveals three main facies: sandy claystone (Crevasse Splay–Interdistributary Bay), carbonaceous claystone (Interdistributary Bay), and coal (Swamp). Overall, the depositional setting is interpreted as a Transitional Lower Delta Plain influenced by tidal activity and fine-grained sedimentation. Proximate analysis indicates that coal seams 6–9 have calorific values ranging from 4968 to 5206 kcal/kg, with low sulfur content (average 0.48%) and ash content of 18.38%. These characteristics classify the coal as High Volatile C Bituminous to Subbituminous B Coal. Variations in lithofacies and the dominance of fine sediments within the Transitional Lower Delta Plain environment contribute to a decrease in calorific value due to higher mineral impurities during deposition