Philosophy of longwall goaf inertisation for coal self-heating control, proactive or reactive?

Self-heating of coal mass has been a long-standing thermal dynamic hazard and also an environmental concern during coal mining, processing, and storage. Especially self-heating of coal in longwall goaf poses a great danger to underground working crew and goaf inertisation is often practiced to combat the hazard. To investigate goaf inertisation with more insights regarding two different philosophies (i.e. proactive and reactive), a three-dimensional non-equilibrium thermal CFD model was developed to study heating evolution and a range of inertisation plans in a modern longwall. The theoretical model mainly incorporated a set of governing equations (e.g. energy conservation, continuity, and momentum balance) and coal oxidation kinetics which are determined by an adiabatic coal heating test. A comprehensive inertisation plan is developed. At initial stage of mining, a proactive inertisation plan is recommended because a heating in start-up area can develop to a fire incident if precautions are not implemented. While a reactive inertisation is suggested after longwall advancing a certain distance as the heating behind longwall face can be left in the fully suffocated zone before escalating to an advanced stage. (C) 2019 Elsevier Ltd. All rights reserved.