Development of effective methods of advance degassing for mines operating outburst-prone coal seams

<jats:p>The aim of the study is to develop new methods of influencing the coal seam to reduce the gas content of coal seams in areas of planned mining operations by increasing their gas recovery into wells and mine workings. The research methods are based on the analysis of domestic and foreign experience, literary and archive materials, the results of natural and experimental observations, and modern methods of computer modeling. Sampling was carried out in the areas under study, with the most gas-bearing seams, which are typical representatives of the area. At all stages of the work, the percentage of oxygen, nitrogen, methane, heavy hydrocarbons (HH), carbon dioxide, and hydrogen was determined. The gas content of the host rocks in the area was determined based on samples taken by core gas collectors equipped with a device for capturing gas released during drilling of the seam and lifting the sample from the well. Sample processing and technical analysis (Ad, W, Vdaf) were carried out in laboratory conditions to determine the component composition of the gas, as well as the calculation of methane content (CH4 + TU). Results (discussion) Among the various methods and techniques for degassing coal seams, there are those that ensure the extraction of methane from the massif that has been relieved of mining pressure and are highly efficient (70-80%): preliminary seam degassing, degassing of the worked-out space using wells drilled from the surface, as opposed to barrier degassing, which is considered to be low-efficient (the extraction of methane from wells drilled parallel to the axis of the workings from special chambers reaches only 2-10%). The following degassing methods have been proposed for the conditions of the Karaganda coal basin: a method for reducing natural gas content with increased gas yield using shock blasting, a method for reducing natural gas content from the earth's surface in advance, a method for degassing coal seams using a refrigerant, and a method for reducing natural gas content. Findings (conclusion). As an example, the Manzhinsky site was examined, where the analysis of samples showed that from the surface of the methane zone (132-167 m) to a depth of 700-800 m, the methane content increases from 81% to 87-93%, and the heavy hydrocarbon content increases from 0.1% to 6-12%. The structural modeling of the well location in the rock mass space in the method of early degassing by an inclined well with branches in the formation revealed that in this case it is necessary to drill an additional vertical well to ensure free gas flow to the surface. The technical and economic comparison of early degassing showed that the method of early degassing by radial drilling of wells proved to be the most economically justified, with an efficiency of up to 60%.</jats:p>