Serhii Hryhorovych Nehrii; Tetiana Oleksandrivna Nehrii; Oksana Viktorivna Zolotarova; Valentyn Anatolyovich Glyva; Andrii Mykolaiovych Surzhenko; Oksana Mykolaivna Tykhenko; Nataliia Burdeina
Abstract
The studies of risk factors on which the safety of miners depends are relevant. These factors include temperature and air velocity within roadways, relative air humidity, dust, noise and vibration, lighting, clutter, limited working space, the difficulty of work, and the collapse of roof rocks. Their ...
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The studies of risk factors on which the safety of miners depends are relevant. These factors include temperature and air velocity within roadways, relative air humidity, dust, noise and vibration, lighting, clutter, limited working space, the difficulty of work, and the collapse of roof rocks. Their greatest concentration is in the technological zones of longwalls, so it is important to determine the priority of taking into account the risk factors in certain zones for planning measures for labor protection in underground coal mining. Therefore, a matrix of priority of risk factors for technological zone longwalls is proposed. The matrix is based on a survey of experienced and well-informed scientists and engineers of coal mines (experts). Fifty experts are involved in the survey.The matrix assesses the priority of risk factors, and considers the technological zones of the longwalls for the planning labor protection measures. The zones of operation of the excavation machines and the end-sections of longwalls are defined as the most safety-critical. Less safety-critical, but also dangerous, are the zones of protection means and the zones of connection of the longwalls with the roadways. The level of a certain risk factor is determined for each zone. The highest priority should be given to the collapse of roofs, dust, clutter of the working space, and the severity of the miners' work. For each risk factor included in the matrix, the technical and organizational measures for labor protection are proposed to reduce the level of injuries for miners.
S. Hryhorovych Nehrii; T. Oleksandrivna Nehrii; H. Viktorivna Piskurska; E. Viktorovych Fesenko; Y. Yevhenovych Pavlov; A. Mykolaiovych Surzhenko
Abstract
In this work, we focus on the technology of stabilizing roof rocks by constructing separate rock supports reinforced with metal grids. Their parameters are specified using the results of physical structural modeling. The reinforced and non-reinforced rock supports with different fractional compositions ...
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In this work, we focus on the technology of stabilizing roof rocks by constructing separate rock supports reinforced with metal grids. Their parameters are specified using the results of physical structural modeling. The reinforced and non-reinforced rock supports with different fractional compositions are arranged and tested. Their initial shapes are similar to rectangular parallelepipeds with the base width-to-length ratios of 1:1, 1:1.5, and 1:2. Their shrinkage is determined by loading the supports regarding the rock particle size and the reinforcement density. Increasing the reinforcement density leads to reducing the linear dimensions without losing load-bearing capacity. It is proved that using the grids conduces the self-wedging of the rock particles. They are most effective at the initial stage of the formation of the load-bearing core. The exponential power dependence of the relative support shrinkage on the grid partitions number is obtained. The bearing core sizes in different supports are determined. For the non-reinforced supports, the core width is about 60% of the initial support width, and for the reinforced ones, it is about 90%. The exponential dependence of the core width-to-height ratio on the number of grid partitions is established. The expression for determining the reinforced support width is obtained. The support stability depends on the smallest initial base size. The size of the rock material has a little effect on the shrinkage. Reinforcement by three metal grids leads to reducing the pliability by 21% and 24% for the supports with the side ratios of 1:1 and 2:1, respectively.
