APPROACH TO EXTRACTING THIN COAL SEAMS

Abstract

The Mae Moh basin is located in the Mae Moh District of Lampang Province, which is about 26 km east of Lampang City. The basin floor is about 320-340 m above mean sea level. The Mae Moh basin consists of three formations, namely the Huai King, Na Khaem, and Huai Luang formations, in ascending order. Their total thickness is nearly 1,000 m. The Na Khaem formation is a coal measure comprising three main coal zones, Q, K, and J. This study introduces preliminary approaches to determining minimum thickness suitable for extracting thin coal seams meeting coal quality requirements or maximum allowable thickness of diluting partings requirements. The approach considers heating value as the main parameter to be determined and considered in different scenarios of losses and dilution. The study findings indicate that high-quality coal-bearing diluting rock partings, such as BK and BK3, can be excavated with K3 coal seam, and the allowable diluting parting thickness ranges 1.68-5.3 m at the required heating value of 2,800 kcal/kg. These diluting parting thicknesses can constitute up to 20-50 % of excavation thickness of K3 coal seam. Low-quality coal-bearing diluting rock partings, such as TK1, TQ, and BQ4, cannot be excavated with K and Q coal seams at all. Coal-bearing partings should have heating value more than 1,000 kcal/kg for having potential to be excavated with coal seams.