Vol 50 Iss. 1

It is known that the movement of vessels (cages and skips) in mine shafts increases resistance. According to A. M. Karpov, the resistance increases up to 10% during medium intensity of operation and up to 25% during intensive operation, when increased turbulence of the flow persists even during short pauses. In narrow shafts, the resistance can increase up to 50%.

Normal sanitary and hygienic working conditions in deep open pits are created by artificial ventilation, which dilutes and removes harmful vapours and gases generated by internal combustion engines and diesel engines, gaseous products of explosive decomposition of explosives, and harmful dust. The urgent need for artificial ventilation arises when the entire volume of the open pit or its deepest parts are filled with harmful substances during inversions, as well as when local accumulations of harmful impurities occur (for example, dust contamination of the atmosphere during bench drilling).

The air ducts used in mines and underground workings for ventilating development workings are largely air-permeable, especially at pipe joints. It is not possible to achieve airtightness even with advanced types of joints (rubber gaskets, rings, banded connections, etc.).

The study of ventilation of blind headings, chambers, longwall faces and other workings after blasting of shot holes using models allows obtaining not only a qualitative characteristic of the process, but also the quantitative relationships necessary for calculations ...

In the mining industry, especially during the construction of hydraulic engineering structures, workings with a cross-section of 50–80 m² are driven over considerable lengths. To ventilate such workings, a large volume of fresh air must be supplied to the face through ventilation pipes. Sometimes this is practically difficult to achieve, since ventilation pipes have high resistance and allow significant leaks.

Regulation of air distribution in a system of mine workings using ventilation openings is always accompanied by a decrease in the total air quantity and additional energy losses caused by an increase in the aerodynamic resistance of the system. Naturally, ventilation openings should be installed so as to ensure maximum control depth with minimum energy losses. This issue becomes particularly relevant in connection with the work currently being carried out in the field of continuous automatic control. On ventilation air currents, a device is needed that regulates the air quantity over a wide range ...

During mine operation, the resistance of mine workings continuously changes due to changes in their length, cross-section, obstructions, wall roughness, etc. A change in the resistance of an individual working included in the mine ventilation system is accompanied by a general redistribution of air in the system of workings, which often leads to unsatisfactory ventilation of the mine. The greatest fluctuations are experienced by the resistance of extraction panels and stopes due to changes in their cross-section and length during the extraction process. Observations show that the resistance of stopes can vary by a factor of 7–8 due to changes in cross-sectional area. Naturally, such significant resistance fluctuations lead to instability of the ventilation and gas conditions in longwall faces and in the panel as a whole. As a rule, the greatest resistance of the face, and hence the minimum air supply, occurs during coal extraction, when the demand for air is maximum. During preparatory operations and in non-working shifts, the amount of air supplied to the face is large and could be reduced ...

One of the main tasks of automating ventilation of mines is the creation of sensors for monitoring aerodynamic parameters of mine air. Normal operation of devices for regulating the flow, pressure and temperature of mine air is impossible without continuous automatic monitoring of their operation. As is known, a number of specific requirements are imposed on instruments intended for use in mines: increased resistance to shock and vibration, leak‑tightness, economy and independence of the power supply source from the mine power grid ...

The specific features of underground mining of mineral deposits in the permafrost zone are decisively determined by the thermal regime of the rock mass and the workings driven in it. Regulation of the thermal regime of mines in these conditions becomes particularly important for improving the safety and efficiency of mining operations ...

Most of the mines we surveyed in the north-eastern part of the country (Norilsk, the Yakut ASSR and other areas) develop mountainous coal deposits lying in the permafrost zone using adit development. As a rule, the mines operate without pre-heating of air during the cold season. Therefore, in the area of extraction panels, with the exception of individual cases, the temperature of the mine atmosphere remains negative throughout the year (minus 2 to minus 4 °C) ...

In recent years, at a number of coal mines in the Kuznetsk, Pechora and Karaganda basins, the heating of all air entering the mine has been practised in winter. At the vast majority of mines located in areas with severe climates both in the USSR and abroad, ventilation systems with heater installations providing partial heating predominate. In such systems, fresh atmospheric air at outside temperature is divided into two separate streams, one of which is heated in heaters to t = 60‑80°C and mixed in the heater channel or at the mouth of the shaft with the other, unheated stream, forming an air mixture with a temperature of t ≥ 2°C. Forced movement of air through the heaters is provided in these systems by special, relatively small fans, called heater fans, as opposed to the powerful main fans that provide ventilation of the mine.

Improvement of working conditions in open-pit operations depends on the use of reliable dust collection means for percussive-rotary and roller-cone drilling rigs operating with air flushing of the borehole. Dust formation during such drilling is so great that under unfavourable conditions drilling rigs can cover the open pit with dust over large areas ...

As is known, the ventilation scheme is one of the factors affecting methane emission from the extraction panel, however its role still remains insufficiently studied. This article presents the results of a study of methane emission under various ventilation schemes at the sections of the former mine No. 3 and mine No. 20 of the Vorkutaugol combine. Mine No. 3 developed the Lower Vorkuta formation of flat seams. The formation contains, in addition to workable seams, a large number of unworkable seams and coal partings, which cause significant methane emission from the goaf, reaching 65–70% of the total panel emission ...

Localization of fire sources is one of the main measures preceding the active extinguishing of fires occurring in underground workings through which fresh air is supplied to workplaces or along which the return air stream moves. Such measures have been developed mainly for cases of opening at a single horizon. They are often automatically transferred to mines with two, three or more horizons, which leads to catastrophic consequences ...

The ventilation regime of mines, especially with active aerodynamic connection of goafs with the surface, is significantly affected by changes in meteorological factors: barometric pressure, temperature and air humidity. A study of literature sources and analysis of statistical data on endogenous fires during the development of thick coal seams in Kuzbass and other coal basins show that in the autumn-winter period fires occur more often than in the rest of the year. Thus, in the Karaganda basin, the most fire-hazardous months are November, December, January and February. The distribution of endogenous fires over the other months is approximately uniform, with the smallest number in June. In the Chelyabinsk basin, according to K. M. Remizov, 1.5 times more endogenous fires occur in October–March than in the remaining months of the year ...

Despite a significant decrease in recent years, the number of accidents in open-pit mining operations still remains high. A study of this issue at a number of quarries in the Southern Urals, Uzbekistan and the Central region showed that the injury rate at night is significantly higher than during the day, and the nature of accidents largely depends on illumination. Thus, over the last seven years at the Sibay quarry, 44.5% of all accidents occurred during the dark hours, at the Blyavinsky quarry – 45%, at the YuGOK quarry – 33%, at the Lebedinsky quarry – 32%, at the Kurgashinkan – 28% ...