Mineral Matter Analysis on Coal and Flanking Rocks in the Bulupoddo District, Sinjai Regency, South Sulawesi Province, Indonesia

Abstract

South and West Sulawesi has coal resources of about 117 million tons or about 0.35% of the total resources nationally. Bulupoddo coal located in Sinjai Regency is a type of coal that is categorized as low rank coal. This study was conducted to identify the minerals contained in coal and its flanking rock (roof and floor) and determine the rank and quality of coal. The methods used are mineralogy and coal quality analysis methods. Field observations shows a type of coal that is about 50 cm thin and flanked by clay and sandstone. The results of microscope and XRD analysis (X-Ray Diffraction) showed minerals contained in Bulupoddo coal, namely in BP-01B (coal) and BP-01E (coal) samples containing kaolinite, illite, pyrite and quartz minerals. In the flanking rock samples, the samples of BP-01A (clay) and BP-01D (clay) contain the minerals kaolinite, illite, pyrite, quartz and chlorite. In the BP-01C (sand) sample indicated as sandstone contains feldspar, quartz and kaolinite minerals. The results of the coal quality analysis that have been carried out on the two coal samples, namely BP-01B and BP-01E, show that the BP-01B sample has a moisture content of 7.74%, an ash content of 54.23%, volatile matter is 23.35%, fixed carbon 14.68%, and total sulfur content by 0.37%. While the sample BP-01E has a moisture content of 9.2%, ash content of 67.76%, volatile matter 18.23%, fixed carbon 4.81% and sulfur content is 0.49%. The calorific value of the test results shows that the coal sample BP-01B has a calorific value of 1953 kcal/gr and BP-01E has a calorific value of 853 kcal/gr. The calorific value of Bulupoddo coal is categorized as lignite B type coal according to coal classification based on ASTM (American Society of Testing Materials).