Many ore mines that have an active aerodynamic connection of underground workings with the surface through the caving zone are ventilated by the injection-suction method. In this method, by regulating the operation of the suction and discharge fan, it is possible to create in the area adjacent to the caving, the so-called zone of zero depression. In this zone, the effective depression is extremely low, so there should be neither air suction from the surface nor air escape from the mine to the surface. The actual large size of the caving area and the occurrence of local natural draughts do not allow for the complete elimination of air movement through the caving. Air may move upward in one part of the caving and downward in another, but in much smaller quantities than with a single fan. Thus, the zero-depression zone created by the blower-suction method of ventilation serves as a measure to control air suction through the caving zone. At mines in the northern regions, the position of the zero depression zone plays an important role in improving the atmospheric conditions of these mines, reducing the entry of cold air from the surface ...
The Zapolyarny mine widely uses high-performance mining systems with massive ore collapse when mining a thick declivity ore deposit. This is associated with the need to detonate large explosive charges during ore stripping and release and, consequently, with the contamination of the atmosphere of underground workings. For the organization of effective ventilation of treatment blocks is important properly designed ventilation scheme and systematic fight against the causes of deterioration of atmospheric conditions at workplaces ...
The present work aims to establish the normal size of air leakage through the mined-out space on the basis of mine observations carried out by the Department of Mine Ventilation of LMI during 1953 and 1954 at 75 mines in Donbass. Although observations of air leakage in 65 faces were carried out, the obtained material was still insufficient to establish the dependence of the norm of air leakage through the mined-out space on the depression between the pumping and ventilation drifts, the elements of bedding, the nature of the roof rocks, the depth of mining, the rate of face movement, etc. All these factors have a greater or lesser degree of influence on the normal size of air leakage through the mined-out space. All this to a greater or lesser extent affects air leakage through the mined space. It is currently impossible to give an expression that would reflect the dependence of the air leakage value on all these factors. The solution of this complex problem requires additional research. We declined to solve this problem also for the following reason: as our observations have shown, air leakage through the mined-out space at change of the specified factors change very insignificantly - within 5-6%.
"In connection with the increase in the depth of development, reaching, in particular, 1000-1200 m in a number of Donbass mines, interest in the issue of natural draft is growing, especially in mines with high temperatures. Natural draft is also important from the point of view of energy conservation. For ventilation of deep mines, fans with a capacity of up to 300-400 m3/sec with an annual power consumption of about 20-30 million kWh will be installed. With such enormous energy resources required for ventilation, taking into account the depression of natural draft when choosing fans will save significant funds for the national economy. Natural draft is of particular importance when ventilating mines of metal mines located in mountainous areas. Many of them, even large ones, are ventilated exclusively by natural draft. Thus, according to measurements in January 1947, at one of the mines of the Soviet Union, with a depression of natural draft of 12.5 mm H2O in winter, 2000 m3/min of air was supplied, which fully ensured the normal operation of the mine. From the above it follows that the question of natural draft in mines is of great practical interest and its correct calculation has considerable production significance.
