DEVELOPMENT OF A DETECTION SYSTEM AND DETERMINATION OF THE DIFFUSION COEFICIENT OF METHANE GAS FLOW THROUGH ROCK FRACTURES AND POROUS ROCKS IN COAL MINES AT A LABORATORY SCALE

• Main Author: Suri Kallo, Nandita
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86094
• Institution: Institut Teknologi Bandung

The emission of methane gas in coal mines has significant negative impacts, such as contributing to the greenhouse effect, which leads to global warming, and the potential to cause methane gas explosions and produce toxic carbon monoxide gas. This highlights the severe dangers of methane emissions during mining and postmining activities. Therefore, monitoring methane leakage is essential for the early detection of potential gas leaks. The Automatic and Continuous Monitoring System — CO? (ACMS-COp) is a system designed to monitor CO? emissions from the ground. However, previous studies of this tool, which utilized soil CO: flux variables, revealed limited flexibility. Thus, further development of the ACMS-COj is necessary to effectively monitor methane Slow in coal mines. This research focuses on the development of the ACMS-CO) into an Automatic and Continuous Monitoring System — CH4 (ACMS-CH4), which can directly measure methane concentrations in the field with greater flexibility. The methane concentration data obtained will then be processed to determine the diffusion and permeability of methane gas, both through rock fractures and porous rock. Numerical modeling will also be conducted to simulate methane gas diffusion through rock fractures and porous rock using the explicit forward Euler method, leveraging Microsoft Excel software. The findings of this study indicate that the diffusion coefficient of methane gas in rock fractures is influenced by the type of fracture, with simple rock fractures diffusing methane gas more guickly than complex fractures. The diffusion coefficient values in rock fractures are higher than in porous rock. Among porous rocks, sandstone has a higher diffusion coefficient compared to siltstone. Numerical modeling shows that the closer an area is to the methane gas source, the higher the methane flow concentration and the type of rock also affects the concentration of methane flow. In this study, siltstone was identified as the rock type with the lowest capacity to transmit methane.