STUDY OF CHARACTERISTICS, QUALITY, DEPOSITIONAL ENVIRONMENT, AND COAL RESOURCES ESTIMATION IN PIT Y PT GAM, KUTAI BASIN, EAST KALIMANTAN

• Main Author: Ari Muladi, Pandum
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69697
• Institution: Institut Teknologi Bandung

Coal is still one of the main energy sources in Indonesia. The research area is located in the mining area of PT Ganda Alam Makmur and has potential coal resources. However, the difference in quality of the coal, especially total sulfur, is problematic. Field observations were carried out in the active mining area of PT Ganda Alam Makmur, and supported by 125 well data, proximate and ultimate test data, and coal quality data, to determine the characteristics, depositional environment and estimation of coal resources. Coal depositional environment was determined by stratigraphic and coal petrographic analyses. Analyses of quality and characteristics of the coal were carried out using proximate and ultimate test data, while modeling and resource calculations were carried out using Minescape 5.7 software. The study area was divided into three lithological units from old to young are, Sandstone Unit, Claystone-Sandstone Unit, and Claystone Unit. These units were deposited in the Middle Miocene at upper delta plain - lower plain delta, as part of Maluwi Formation. Geological structure that was developed in the study area is syncline that is interpreted as a result of the Samarinda Anticlinorium formation during Middle Miocene. Stratigraphic analysis results show that the study area were classified into twelve lithofacies, which are grouped into four facies associations: distributary channel, interdistributary bay, flood plain, and distributary mouthbar, which were formed in the upper delta plain and lower delta plain environments. Changes in transgression and regression phases that occurred several times, caused variations in the total sulfur values. Coal petrography analysis was performed to calculate maceral composition in the coal samples, which were then used to calculate the Tissue Preservation Index (TPI) and Gelification Index (GI) to interprete the depositional environments. Seven coal samples from six different seams were analyzed and show that coal from seams B and C were deposited in the upper delta plain, while the coal in seam E2, G, N2, and P1 were deposited in the lower delta plain. The results of the coal quality analysis show that the coal at the study area is ranked as Subbituminous B Coal to Subbituminous A Coal, with an average calorific value of 5333.00 kcal/kg. Coal resources in the research area have total inferred resources of 6,981,468.79 tons, indicated resources of 11,460,039.64 tons, and measured resources of 47,236,673.35 tons.