The influence of the shape and size of dust fractions on their distribution and accumulation in mine workings when changing the structure of air flow

Abstract

The results of the analysis of statistical data on accidents at Russian mines caused by explosions in the workings space have shown that explosions of methane-dust-air mixtures at underground coal mines are the most severe accidents in terms of consequences. A detailed analysis of literature sources showed that in the total number of explosions prevails total share of hybrid mixtures, i.e. with the simultaneous participation of gas (methane) and coal dust, as well as explosions with the possible or partial involvement of coal dust. The main causes contributing to the occurrence and development of dust-air mixture explosions, including irregular monitoring of by mine engineers and technicians of the schedule of dust explosion protective measures; unreliable assessment of the dust situation, etc., are given. The main problem in this case was the difficulty of determining the location and volume of dust deposition zones in not extinguished and difficult to access for instrumental control workings. Determination of the class-shape of coal dust particles is a necessary condition for constructing a model of the dust situation reflecting the aerosol distribution in the workings space. The morphological composition of coal mine dust fractions with dispersion less than 0.1 has been studied. Particle studies conducted using an LEICA DM 4000 optical microscope and IMAGE SCOPE M software made it possible to establish the different class-shapes of dust particles found in operating mines. It was found that the coal dust particles presented in the samples correspond to the parallelepiped shape to the greatest extent. The mathematical model based on the specialized ANSYS FLUENT complex, in which this class-form is incorporated, is used for predicting the distribution of explosive and combustible coal dust in the workings space. The use of the obtained model in production conditions will allow to determine the possible places of dust deposition and to develop measures to prevent the transition of coal dust from the aerogel state to the aerosol state and thereby prevent the formation of an explosive dust-air mixture.

Fundamentals of forecasting explosive gas accumulation formation in working areas of coal mines

“…Due to the fact that at the majority of objects of mining operations for the solution of certain tasks, including those of scientific nature, three professional programmes are mainly used: "Computational Fluid Dynamics (CFD)-complex FlowVision", "SolidWorks" and ANSYS Fluent [2,11,12]. According to the preliminary results of modelling, one of which is presented in Figures 2, we determined that the most suitable for solving the problems we face are software packages FlowVision and ANSYS Fluent.…”

“…On the basis of the above stated we consider that the increase of reliability of results of aerogas situation control by means of modern monitoring means is an urgent task. In addition, the solution of this problem will also contribute to the increase in the efficiency of management of the process of ventilation of mine workings and, first of all, of mining areas and will lead to an increase in the safety of coal mine life on the gas factor [5,12].…”

Optimization of the Combined Ventilation System for Dust Reduction in Blind Headings of Potash Mines

“…Currently, the method of dust suppression in mine headings with the use of water prevails in iron ore and coal deposits. In coal mines, where dust can be explosive [5,6], and polymetallic mines, wet dust suppression methods are commonly employed since fire and technical water pipelines are laid to the sites of mining operations. However, this is not as common in potash mines due to the big size of the mine field.…”