During mining operations, toxic and explosive gases are released into the atmosphere of the mine. Safe working conditions for miners are provided by forced ventilation using main and local ventilation fans. In dead-end mines that do not have a through passage, fresh air is supplied through ventilation ducts. As a result of its impact on the bottom, that is, on the surface of the rock mass, turbulent vortices are often formed. They are chaotic and can either worsen ventilation or improve it. Scientists from Perm Polytechnic University and the Mining Institute of the Ural Branch of the Russian Academy of Sciences have figured out how to properly position a ventilation pipeline in order to improve the quality of ventilation of dead-end mine workings and the safety of workers.
The article was published in the journal “Izvestia TulSU. Earth Sciences”, 2024. The study was carried out with the financial support of the Ministry of Education and Science of the Russian Federation as part of a state assignment.
Dead-end underground workings are called, which do not have a through passage. High–quality ventilation is a serious task that prevents the accumulation of dangerous gases in the atmosphere of the mine and poisoning of miners. At the same time, the proper arrangement of the ventilation system in the mines depends on many factors, including the movement of air masses through the working area and vortices that occur after the impact of a fresh stream on the mountain range.
Today, the injection method of ventilation is actively used, when clean air is supplied by fans through a ventilation pipeline, which is laid almost to the end of the dead-end mine. Scientists from Perm Polytechnic University and the Mining Institute of the Ural Branch of the Russian Academy of Sciences have found out that the length, structure and shape of a vortex can be determined by such an indicator as the satellite flow of air directed from the pipeline to the face.
Nowadays, for a more detailed and in-depth study of various physical processes in the mining industry, three-dimensional modeling methods using computer programs are increasingly being used. This method allows you to analyze the behavior of objects in various conditions and predict the results of experiments even before they are carried out, or using model validation to confirm the results of scientific hypotheses.
Based on this, the researchers developed a three-dimensional model of a 28-square-meter and 100-meter-long production facility, which houses a ventilation pipeline that supplies fresh air to the production facility. The model made it possible to track in detail how different variants of the location of the ventilation pipeline in the section of the workings affect the intensity of the vortex. They also determined the length of its coverage area, that is, the mixing zone of air flows, which directly affect the safety and effectiveness of ventilation.
The scientists considered different options for the pipeline end to lag behind the face wall: 15 and 30 meters. The magnitude of the vortex was also calculated for several ways of its location in the mine: in the central part, in the corner, under the roof, at the height of a person’s height.
The model showed that for the best operation of the ventilation system, it is necessary that the air jet after exiting the pipeline is pressed against the walls of the workings and does not turn around prematurely. This will make it more efficient to flush out dangerous gases from the work area.
– The best option for lagging the end of the pipeline by 15 and 30 meters is observed when it is placed in one of the lower corners of the workings. This creates the widest area for the air jet to turn around at the face wall. Its placement in the center under the roof is less effective,” explains Alexey Tatsiy, senior lecturer at the Department of Mining Electromechanics at PNRPU, engineer at the Mining Institute of the Ural Branch of the Russian Academy of Sciences.
A study by scientists from Perm Polytechnic University and Ural Branch of the Russian Academy of Sciences confirmed the strong influence of the position of the ventilation pipeline on the quality of ventilation from dangerous gases released during mining operations. As a result, the best option for its placement in dead-end mining operations was determined. The application of the identified parameters in the mining industry will increase the safety of miners.