Study of the characteristics of organic mining materials affecting their explosive properties

The article analyzes the explosive and fire-hazardous properties of coal dust of various dispersions using the example of coal mine dust. The authors proposed sample preparation methods for obtaining and studying dust fractions with a dispersity of less than 800 microns. The results of a study of the shapes of dust particles are presented. To study the characteristic particle sizes the authors suggested using the optical microscopy method implemented using a LEICA DM 4000 microscope and the “Image Scope Color” information processing application. To assess the reactivity of dust particles, the authors used a simultaneous thermal analysis method implemented using an STA 449 F1 Jupiter with NETZSCH Proteus Software. The results of a thermogravimetric study of narrow fractions of organic coal dust are presented. The influence of dispersion on the explosive properties of dusts has been established. The results obtained showed the need and expediency of further study of precisely fine fractions of explosive dusts of this kind

Prerequisites for applying the risk-based approach to assessing the explosive and fire hazardous properties of underground mining materials

The relevance of the work is due to the introduction of new high-intensity mining technologies underground, the conduct of mining operations at ever greater depths of coal and ore, changes in the explosive properties of the extracted raw materials, as well as incidents and accidents of varying severity occurring at mining facilities. There is an opinion that one of the causes of accidents and emergencies in mines is the inability to take into account both the features of the manifestation of the properties of the rock mass and the change in the explosive properties of minerals. The problem of applying a risk-oriented approach, namely a comprehensive assessment of the risk of accidents, in this case fires and/or explosions, has not been resolved. The applied risk calculation methods are diverse, as a rule, the accuracy of the results is low, and none of them allows taking into account all the identifiable hazards that lead to the occurrence of endogenous and exogenous fires, as well as explosions of hybrid mixtures in the space of mine workings. This article attempts to study in detail the prerequisites for applying a risk-based approach to solving this problem. Theoretical approaches and risk assessment in mines and mines are considered and methods are given that allow in express mode to obtain up-to-date information on the explosive and fire hazardous properties of the extracted raw materials

Comprehensive research method for explosive coal dust

The article briefly analyses the explosion and fire hazard properties of coal dust of different dispersions. It is emphasised that many experts working in the field of explosion protection and industrial safety pay insufficient attention to changes in the properties of the dust when reducing its dispersity. It is suggested to develop a new, complex methodology based on the dispersed composition of coal dust. The authors suggest to put methods of special sample preparation and dispersing of samples in two stages as a basis of the complex methodology. To do research with the help of thermal synchronous analysis of the smaller fractions, the authors propose to regrind the coal fraction obtained after the cone crusher in an analytical mill. To exclude adhesion of particles due to the process of static charges accumulation it is suggested to use impactless sieving machine of Retsch company which allows to take out the accumulated charges of static electricity. The coal dust fractions obtained after sieving were sent for granulometric analysis by a dynamic image processing method in CAMSIRE and by an optical microscopic method using a LEICA DM 4000 with image scope colour processing. A simultaneous thermal analysis was performed selectively for fractions smaller than 1000 μm. This was carried out with an STA 449 F3 and NETZSCH Proteus termal analysis application software. The authors consider that the obtained results allow to conclude that it is further expedient to carry out research work in this direction and will make it possible to develop recommendations aimed at prevention of coal dust aerosol explosions