The annual increase of coal production and its demand lead to the necessity in temporary storage places (warehouses) organization to accommodate raw coal materials before the shipment. It is noted that at the open method of coal storing the dust emission from loading/unloading operations and from the pile surface effects negatively the health of the warehouse workers and adjacent territories. An alternative solution is closed-type warehouses . One of the main hazards of such coal storage can be the release of residual methane from coal segregates into the air after degassing processes during mining and extraction to the surface, as well as transportation to the place of temporary storage. The study carries the analysis of methane content change in coal during the processes of extraction, transportation and storage. Physical and chemical bases of mass transfer during the interaction between gas-saturated coal mass and air are studied. It is determined that the intensity of methane emission depends on: the coal seam natural gas content, parameters of mass transfer between coal, and air and the ambient temperature. The dynamics of coal mass gas exchange with atmospheric air is evaluated by approximate approach, which is based on two interrelated iterations. The first one considers the formation of methane concentration fields in the air space of the bulk volume and the second accounts the methane emission from the pile surface to the outside air. It is determined that safety of closed coal warehouses exploitation by gas factor can be ensured by means of artificial ventilation providing volumetric methane concentration in the air less than 1 %. The flow rate sufficient to achieve this methane concentration was obtained as a result of computer modeling of methane concentration fields formation in the air medium at theoretically calculated methane emission from the pile surface.
Compressed air as a type of safe technological energy carrier is widely used in many industries. In economically developed countries energy costs for the production and distribution of compressed air reach 10 % of the total energy costs. The analysis of compressed air production and distribution systems in the industrial sector shows that the efficiency of the systems is at a relatively low level. This is due to the fact that insufficient attention is paid to these systems since the compressed air systems energy monitoring has certain difficulties – the presence of complex and branched air pipeline networks with unique characteristics; low sensitivity of the equipment which consumes compressed air; the complexity of auditing pneumatic equipment that is in constant operation. The article analyzes the options for reducing the cost of production and compressed air distribution. One of the promising ways to reduce the compressed air distribution cost is timely detection and elimination of leaks that occur in the external air supply network of the enterprise. The task is solved by hardware-software monitoring of compressed air pressure at key points in the network. The proposed method allows real-time detecting of emerging air leaks in the air duct network and sending commands to maintenance personnel for their timely localization. This technique was tested in the industrial conditions of ALROSA enterprises on the air pipeline network of the Mir mine of the Mirninsky Mining and Processing Plant and showed satisfactory convergence of the calculated leakage values with the actual ones. The practical significance of the obtained results is that the developed method for monitoring air leaks in the air duct network is simple, it requires an uncomplicated software implementation and allows to localize leaks in a timely manner, thereby reducing unproductive energy costs at the enterprises.
Based on the analysis of the mining and geological conditions for developing coal deposits in Vietnam, the existing mining safety regulations, the application of methods for calculating the air supply of working and development faces using the methane factor and modern methods of mathematical modeling of the ventilation of mines threr was developed the procedure for analyzing the efficiency of air distribution management considering the proposed indicator - energy efficiency coefficient for ventilation systems, determined by the efficiency of air use and energy consumption. Relations have been obtained that determine the relationship between the aerodynamic resistance of negative regulators, the number of simultaneously developed working and development faces, the performance of main ventilation fans and the consumed electric power.
The article describes climatic and mining-technical conditions influencing frost formation process. It was noted that the radical tools for preventing frost formation in winter periods is creation of positive temperature in tunnels by heating the incoming outside air. We formulated tasks, which solution will promote development of engineering calculation method for heating systems parameters. The article provides results of theoretical studies based on mathematical modelling and analytical solutions and data on field instrumental measurements, which were processed with similarity criteria. It compares mathematical modelling results on determining amount of tunnel incoming air flow with portal gates and calculations data from experimentally determined coefficient of local resistance. We proved the energy efficiency of placing the tunnel portal gates and validated the places of preheated air injection points and removal of cool air from this flow, which provides maximal energy effect.
The characteristic of Russia and foreign vehicle tunnels are provided in paper and advantages of their placement in the conditions of the city are noted. It is shown that one of the main factors defining negative impact on environment in the period of tunnels driving is mine equipment, and at operation – vehicles. The analysis of essential differences of features of pollution of atmospheric air at construction of tunnels from its pollution at construction of buildings on a surface is given. The examples illustrating levels of negative impact of the upcast ventilation shaft airflow on atmospheric air are given and the ventilation schemes reducing this influence are offered. It is shown that during operation of road tunnels of pollution of the air environment can extend on considerable distances from tunnel portals. Numerical calculations of concentration of carbon oxides and nitrogen during removal of the upcast ventilation shaft airflow through portals and through the mines built near them are executed. Technical solutions on purifications of tunnel air by means of electrostatic filters are described.
On the basis of instrumental measurement data the major factor defining a radiation environment in underground facility of Saint Petersburg the subway are radon and radon daughters is shown. The hypothesis of influence on dynamics of radon accumulation in underground facility of the moisture entering from rocks is confirmed.
On the example of coal mines of Vorkuta it is shown that in the coal industry of Russia it is necessary to consider as an essential reserve of increase of production safety realization of the organizational actions directed on preventive identification of violations of safety regulations, potentially bringing to accidents, carrying out behavioural security audits, and also involvement of miners in management of occupational safety and health and industrial safety.
The mine technical features of building of underground structures determining selection and parameters of ventilating systems and an air conditioning are reviewed, the engineering solutions on increase of control efficiency by quality of air are offered.
It is noted overburden dump which are forming on open-pit mining of mineral deposits, are powerful sources of environment impact, including the population living in areas on which dust pollution extends. Procedure of zonation of the territory surrounding overburden dump on size of technogenic risk is developed. As an example, the assessment of distribution of technogenic risk for conditions of overburden dump of Olenegorsky combine is carried out.
Results of field observation of atmospheric air pollution at a construction of transport tunnels on highway and railway Adler – Red Forest Meadow are presented. Features of an environmental pressure dynamics on atmospheric air are determined. The estimation of pollutant emission influence from transport tunnels on atmospheric air is given. Possibility of concentration of pollutants decrease in atmospheric air at the expense of ventilation shafts use for removal from the tunnel of outgoing air flow is shown.
For effective ventilation Kuznetsovsky railway tunnel the longitudinal scheme of ventilation based on use of jet fans is offered. It is shown that use of the offered scheme of ventilation at influence of natural draft and piston effect of trains is impossible without an automatic control system of ventilation (ACSV). The principles of work ACSV taking into consideration natural and operational factors are proved.
Classification of damage from accidents and crashes is given. Procedure optimization expenses for a labour protection and definition of economically sound risk of accidents and crashes is offered. The estimation of economic efficiency of personnel development serving the self-propelled mining equipments on ore mine «Northern» of industrial complex «Pechenga Nikel» is carried out.
The problems of seismic impact of explosion on a tunnel are characterized. A methodology for determining the parameters in Sadovsky's formula for seismic wave displacement velocities based on the results of measurements at one point of the velocity time histories of seismic oscillations from subsequent short-term delayed explosions is proposed. The correlation between the parameters is established. The influence of errors in the determination of parameters on the calculation of seismically safe mass of the explosive charge is estimated.
Суровый климат и залегание многолетнемерзлых пород характеризуют почти 2/3 территории России. Значительная амплитуда колебаний температуры атмосферного воздуха, составляющая 70-100 ° С, определяет знакопеременный характер тепло- и массообменных процессов в горных выработках. Эти процессы оказывают влияние на многие аспекты безопасности и эффективности добычи полезных ископаемых, а также эксплуатации подземных сооружений. Дана характеристика влияния термодинамических параметров рудничного воздуха и горного массива на здоровье людей и производительность труда, запыленность воздуха, устойчивость горных пород, образование наледей, проветривание и т.д. Отмечается разница в принципах регулирования теплового режима подземных выработок в условиях многолетнемерзлых пород и при высоких температурах горного массива. Дан анализ причин, затрудняющих эксплуатацию подземных сооружений. Описаны особенности формирования и управления тепловым режимом железнодорожных тоннелей. Отмечен вклад ученых и выпускников горного факультета института в разработку теплофизических основ обеспечения безопасности и эффективности добычи полезных ископаемых и эксплуатации подземных сооружений.
The main factors determining the peculiarities of accident-free operation of railway tunnels under windless climate conditions are considered. It is shown that ice formation caused by a combination of two unfavorable phenomena: relatively low air temperature in the tunnel and high watering of the tunnel is especially dangerous. The paper presents the results of the experimental studies indicating that the gas composition of the tunnel air is determined not only by the harmful gaseous impurities emitted by the carriers but also by methane, carbon dioxide, hydrogen sulfide and radon coming from the surrounding rocks and water. The mechanism of radon impact on tunnel personnel has been studied and a large-scale description of its possible impact on air quality in the tunnel has been given. Many regions of the Russian Federation, including those where the longest railway tunnels of Russia are located: Baikalskiy and Severo-Muiskiy, can be classified as radon hazardous. Creation of rational ventilation conditions influencing not only the radiation situation but also the thermodynamic characteristics of the air should be considered as a fundamental means of achieving the required air quality in the tunnels. In order to increase the stability of ventilation conditions the possibility of using different regulating devices has been studied. The maximum influence on the air flow is exerted by the installation of a ventilation door, which allows to change the air inflow by 70% of the initial indicator. The principles of creation of the favorable temperature conditions in the railway tunnels, which is one of the effective means of ice formation prevention, have been implemented and tested on site.
