Longwall mining is the safest and most economical way to mine coal in underground mines. At present 37 longwall panels in 11 states are mining more than 50% of underground mined coal. Proper degasification of the panels prior to mining and post mining promotes mine health and safety and improves productivity. Produced gas can be sold for added profit. For proper degasification, all coal seams are divided as shallow, medium-depth and deep coal seams. The degasification scheme for a typical mine in each category is discussed in detail. Special attention is given to floor gas capture that has led to some recent coal mine disasters.

The gas content and composition are widely utilized in underground coal mining to evaluate the potential for coal and gas outbursts. This study investigates the in-situ coal seam gas content and gas sorption capacity in three coal seam sections (A1, A2, and A3) in Sydney basin to understand their implications for gas management and outburst risk in Australian coal mines. The fast direct desorption method and associated devices were described in detail and employed to measure the in-situ coal seam gas components (Q1, Q2, and Q3) and gas composition. This method offers a reliable and accurate approach for assessing coal seam gas content and composition, with an error factor of ± 15%. The results revealed gas contents in the A1 and A3 sections exceeding Level 2 Threshold Limit Values (TLV), necessitating gas drainage measures. High-pressure isothermal gas sorption experiments were conducted on coal samples from the A1, A2, and A3 seam sections to investigate their gas sorption capacity. The Langmuir model demonstrated excellent performance in describing CO2 sorption behavior, with fit coefficients R² greater than 0.99. The study observed a strong positive correlation (Pearson's coefficient >0.855) between in-situ gas content and Langmuir volume, suggesting that higher sorption capacities correspond to higher in-situ gas content in coal seams. The findings of this study highlight the importance of understanding the relationship between in-situ gas content and gas sorption capacity in managing gas emissions and mitigating outburst risks in underground coal mines. The insights derived from the study can contribute to the development of effective gas management strategies and enhance the safety and efficiency of coal mining operations in Australia.

The evolution of major coal oxidation and resulting sponcom incidents are sudden and may result in catastrophic negative safety outcome or result in the withdrawal of persons and closure of longwall panels/mines. Historically, experiences of highly gassy longwall workings in Australian Goonyella Middle (GM) seam (late-1990's to mid-2020's), increasing trend in CO levels and associated coal oxidation and sponcom indicator gases and related incidents due to oxygen ingress on maingate side was the major safety issue. The original Australian active longwall goaf gas drainage system designs are based on the historic work of CSIRO, supported by the operational experiences. 
Over two decades ago, active goaf gas drainage flow rates were moderate (2,000 l/s to 3,000 l/s) and the oxygen ingress on TG side was not a major concern. However, with increasing goaf gas drainages rates and manual or automated mode operation of goaf wells to extreme flow rates to address higher longwall goaf gas emissions, TG oxygen ingress and air wash zones became a major issue recently, necessitating the introduction of TG inertisation strategies now to address this emerging issue. Introduction of MG proactive inertisation strategy had ultimately reduced the number of high CO or intensive oxidation incidents over two decades. This paper provides practical safety benefits of longwall tail gate (TG) inertisation supported by the original computational fluid dynamics (CFD) modelling studies carried out by the CSIRO. The field verification with both MG and TG inertisation using proactive N2 injection during various phases of longwall production and stoppages in an active longwall provides reasonable technical and operational justifications on gas and sponcom management strategy for worker's safety.