Coal characteristics of the eocene to pliocene epoch: A case study in the Berau Sub-basin, East Kalimantan, Indonesia

A complex material, coal is primarily composed of carbon, hydrogen, oxygen, nitrogen, sulfur, and other minerals. The research area is located in the Berau Sub-basin, which is part of the Tarakan Basin. The oldest to youngest formations are Sembakung, Latih, Labanan, and Sinjin. From such formations, 20 coal samples were taken. The aim of this project is proximate analysis to identify the characteristics of coal in each formation and regression analysis to explore the correlation between total moisture, ash content, and calorific value. Each formation's vertical column drilling provided coal samples, and they were tested using proximate analysis to determine total moisture, ash, volatile matter, fixed carbon, and calorific value. The Sembakung Formation has 5.72% total moisture, 25.65% ash, 19.70% volatile matter, 53.75% fixed carbon, and 6069 kcal/kg calorific value. The Latih Formation averages 29.87% total moisture, 4.03% ash, 39.69% volatile matter, 37.89% fixed carbon, and 5406 kcal/kg calorific value. The Labanan Formation averages 42.07% total moisture, 3.33% ash, 43.23% volatile matter, 40.25% fixed carbon, and 5488 kcal/kg calorific value. The Sinjin Formation averages 47.95% water, 3.08% ash, 40.56% volatile matter, 39.12% fixed carbon, and 5405 kcal/kg calorific value.