Simulation of methane emission during open coal mining

According to statistical reports of coal enterprises for 2015–2019 43 open-pit mines are working in the methane zone. At the same time, it can be stated that enterprises are not developing measures to reduce greenhouse gas emissions. This is largely due to the lack of a model for methane emission into the working area of the mine. The main sources of methane emissions from open-pit mines and the factors influencing them have not been identified. The purpose of the study is to determine the main sources of methane emissions during open-pit coal mining and the main characteristics on which gas emission depends. In this regard, the paper presents the results of modeling methane emissions during open-pit coal mining and solving the analytical problem of methane emissions. The analysis was carried out for three sources of methane emissions: when drilling wells; from exposure of a carbon rock massif; and during coal transportation. Based on the results of the study, the main sources of methane emissions into the atmosphere from open-pit coal mining were considered. It was also taken into account that methane can be emitted from both coal seams and host rocks. An averaged cross section was analyzed, leading in the methane zone. Gas emission patterns depending on the permeability value, geometric parameters of the section field, drilling and blasting wells, coal particle sizes and other parameters were identified. It was determined that the values of gas emission can affect the concentration of methane in the atmosphere of the section, as well as the fire safety of surface mining operations. Studies on determining the possibility of exceeding the maximum permissible concentration of methane in the atmosphere of the cut and the possibility of its ignition have been updated.