Influence of longwall gateroad convergence on the process of mine ventilation network-model tests

Abstract

Hard coal mines are required to constantly ventilate mine workings to ensure that the air composition is at a certain humidity and temperature level that is comfortable for underground mine workers, especially in deep deposits. All underground workings, which are part of the mine ventilation network, should be ventilated in a way that allows maintaining proper oxygen concentration not lower than 19% (by volume), and limits concentration of gases in the air such as methane, carbon monoxide or carbon dioxide. The air flow in the mine ventilation network may be disturbed due to the natural convergence (deformation) and lead to change in its original cross-section. Reducing the cross-sectional area of the mining excavation causes local resistances in the air flow and changes in aerodynamic potentials, which leads to emergency states in the mine ventilation network. This paper presents the results of numerical simulations of the influence of gateroad convergence on the ventilation process of a selected part of the mine ventilation network. The gateroad convergence was modelled with the finite element software PHASE 2. The influence of changes in the cross-sectional area of the gateroad on the ventilation process was carried out using the computational fluid dynamics software Ansys-Fluent. Keywords: Geomechanics, Convergence, Numerical modelling, Ventilation process, Support