The Impact of Pit Ventilation System on Protective Isolation Walls in Coal Mine

Underground coal mining is impossible without the use of protective pillars or protective isolation walls. Regardless of the method of coal mining (longwall method, room and pillar etc.), they all require the use of pillars or protective isolation walls. Their application is present in the exploitation of all types of coal. Today, the design of pillars and protective isolation walls is carried out in the same way. All of them, regardless of their physical and mechanical properties or the applied excavation method, undergo changes over time. Changes can occur due to mechanical damage (mining, rockfall, vibrations due to transport, gas outbursts, etc.) or due to the influence of the pit ventilation system. Although the influence of the ventilation system of the pit on the protective insulation walls is established and known, it has been very little addressed and treated in the literature or concrete research. After the formation of a pillar or isolation wall, under the influence of the pit ventilation system, moisture and gases begin to be released from it, and the cohesive and adhesive forces in it weaken, which also leads to rheological changes. It has been established that in isolation walls where moisture is periodically or constantly introduced and increased for some reason, most often in order to eliminate coal dust, the intensity of rheological changes is lower than in those where this is not done. The paper presents the results of research into the changes that occurred in protective insulating walls used in brown coal mining due to the influence of the pit ventilation system over a certain period of time. Changes in the design of protective columns and insulating walls, taking into account the influence of the pit ventilation system on them, are also proposed.