Vol 46 Iss. 1

As it is known, the gas balance of the preparatory workings consists of two main components: gas emission from the face and from the sides of the workings. Therefore, the study of the patterns of gas emission from the exposed surfaces of the formation in the preparatory workings is of great practical importance both for the organization of ventilation of the excavation during the period of its implementation, and to determine the impact of gas emission from the preparatory workings on the gas content and gas balance of the area and the mine.

Working in a quarry is subject to the influence of meteorological conditions characteristic of the area and harmful impurities emitted into the atmosphere of the quarry during various production processes. Precipitation, changes in temperature and wind speed at the surface entail changes in the corresponding parameters at workplaces. The most unfavorable of all natural factors is temperature, since most of the quarries of the USSR is located in the zone of sharply continental climate with average winter temperatures of minus 15-20 ° and summer temperatures of +20-30°.

Methane emission within the excavation area depends on the operation of mining machines, atmospheric pressure fluctuations, collapse of rocks of the main roof, irregularity of air supply, etc. Regardless of the influence of these factors, the methane content in the outgoing jet of the site should not exceed 1%. Consequently, it is necessary to supply to the site such amount of air Qpred that would ensure compliance with the requirements of Safety Rules at any combinations of these factors.

In the process of operation of mines there is a need for depression surveys and survey of ventilation, as a result of which are measured: the total flow rate of fans, the amount of air entering the mine, leakage, the amount of air reaching the cleaning and preparation faces, depression of individual jets, sections and the mine as a whole and other ventilation parameters. As a result of the survey should be outlined measures to improve the ventilation of the mine, including reducing air leakage.

Calculation of mine air ducts by analytical and graphoanalytical methods is mainly reduced to the determination of two values: 1) air leakage or delivery coefficient μ; 2) head h, which is necessary to create, so that to the end of the stack of pipes a given amount of air Qzab. Many formulas for calculation of these values have been proposed. A. I. Shvyrkov on the basis of theoretical studies of air movement in air-permeable pipelines established a functional dependence between the values of.

The phenomenon of air recirculation during the operation of partial ventilation fans as a cause of gasification of dead-end excavations is insufficiently studied. As is known, recirculation at partial ventilation is a harmful phenomenon, and in gas mines dangerous, as it leads to an increase in methane concentration in the workings above the established standards. In workings where blasting operations are carried out, recirculation prolongs the time of face ventilation and can lead to an increase in the concentration of harmful gases. I. A. Babokin, analyzing the causes of methane accumulation before blasting over a ten-year period, came to the conclusion that in 8% of cases the accumulation was due to recirculation. The current Coal and Shale Mine Safety Regulations provide a number of restrictions that preclude the possibility of recirculation.

The possibility of using the wet method of dust suppression at the mines of the Norilsk Combine during excavation, loading and transportation of coal was established by thermometric measurements of air and host rocks along the course of the ventilation jet. The research was carried out by the staff of the Department of Mine Ventilation of the Leningrad Mining Institute in 1959-1960.

The main means of dust control besides ventilation is irrigation. Production studies at coal mines have shown that irrigation reduces the dustiness of the air at workplaces by 5-15 times. Application of this effective method of dust suppression at the mining enterprises of the Far North is complicated by severe climatic conditions in underground workings and low temperature of rocks. The air temperature in the majority of coal mine workings in the permafrost zone remains negative throughout the year, which excludes the use of water for dust suppression.

The study of the nature of gas distribution in the quarry at stable and unstable states of the atmosphere allows to establish “the actual amount of air ventilating the quarry, taking into account certain atmospheric conditions.On the nature of gas distribution in quarries in the literature there is no information. The main factor of natural ventilation of quarries V.S. Nikitin considers wind energy. This is at variance with our experimental data.

Air exchange in quarries is formed under the action of wind energy and convective flows resulting from the temperature heterogeneity of the atmosphere by height. These factors can act together and separately.In the presence of wind and developed convective flows, air exchange is the most complete and active. The presence of only convective air flows in the absence of wind somewhat worsens air exchange, but provides active transfer of harmful impurities from the lower part of the quarry to the upper zone and beyond the quarry space. Sometimes wind energy is considered sufficient for air exchange in quarries. However, the decisive role in the implementation of air exchange in quarries play convective flows, formed due to a certain temperature stratification of the atmosphere.

Local artificial ventilation of workplaces of quarries with the help of partial ventilation fans has not been studied so far, although in the literature there are indications on the possibility of its application in quarries. Experiments on ventilation of individual workplaces in Sibaysk and Mindyak quarries were conducted in November and December 1960.

The wide introduction of mechanisms with internal combustion engines in the mining industry has led to the need to create protective devices from harmful and poisonous impurities contained in the exhaust gases (carbon monoxide, nitrogen oxides, aldehydes, lead oxides, etc.). Depending on the type of engine and its design, as well as the fuel used, the composition of exhaust gases may vary.

About 40% of coal production in Kuzbass falls on the Prokopyev-Kiselevsky district. Of all commercial coal reserves as of January 1, 1960. 64,5% are concentrated in seams with thickness over 3,5 m, including 41,5% in seams with thickness over 6 m. Of the 25 mines in the district, seven are mining at the first, fourteen at the second, three at the third and one at the fourth horizons. Nine mines are preparing the underlying horizons, including four mines are preparing the second, four mines - the third and one mine - the fourth horizon.

As is known, the main parameters of mines - productivity and service life - largely determine their technical appearance and the level of technical and economic performance. The choice of these parameters is related to the possible load on the seam, which for a single seam determines the production capacity of the mine, and for a suite of seams - also the sequence of their mining.Increasing the load on the seam and enlargement of mines are one of the main directions of technical progress in the coal industry in the coming years.