RU2371583C2 - Prevention method of explosions of methane in mines - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method includes insulation of mines, in which it is extracted methane, from air inflow and increasing of methane concentration ensured by extraction of it from excavated coil, open area and containing rocks up to values, exceeding top limit of methane explosibility. After insulation of mines it is filled by inert gas, reducing concentration of oxygen up to explosion-proof values. After that it is increased concentration of methane ensured by natural influx up to values, exceeding top limit of methane explosibility.

EFFECT: effectiveness increase of prevention method of methane explosions, and safety increasing of mining.

2 cl

Description

The invention relates to the mining industry and can be used to combat methane explosions in mines.

There is a method of preventing methane explosions in mines by feeding inhibitors, for example, HFC 114B2, into the gas mixture (Umnov A.E., Golik A.S., Paleev D.Yu. et al. Prevention and localization of explosions in underground conditions. M., Nedra , 1990. - 286 p.).

The disadvantage of this method is the inability to fill and maintain the required concentration of inhibitor in the entire volume of mine workings, where methane may appear, due to the supply of fresh air to the mine.

There is also a method of preventing methane explosions in mines, including changing the concentration of methane to explosion-proof values by diluting it with an air flow (Labor protection: Textbook for universities / K.3. Ushakov, B.F. Kirin, N.V. Nozhkin, etc. Under Edited by K.Z. Ushakov, Moscow: Nedra, 1986.- 624 p.).

The disadvantage of this method is its low efficiency in mines with a high methane emission rate, soufflare emissions, coal and combustible gas emissions.

The closest technical solution is a method for preventing methane explosions in mines, including isolation of the mine workings in which methane is released from the influx of fresh air and increasing methane concentration by extracting it from the mined coal, the mined space and the surrounding rocks to values exceeding the upper explosive limit methane (RU 2189448 C1 (Nosenko V.D. et al.), publ. 09/20/2002).

The disadvantage of this method is the low efficiency in the period of increasing methane concentration in isolated mines when an explosive mixture is formed.

The objective of the invention is to increase the efficiency of the method of preventing methane explosions in mines.

The problem is achieved in that in a method for preventing methane explosions in mines, including isolating the mine workings in which methane is released from the influx of fresh air and increasing the methane concentration by extracting it from the mined coal, the mined-out space and the surrounding rocks to values exceeding the upper the methane explosive limit, according to the invention, after isolation of the mine workings, they are filled with an inert gas, reducing the oxygen concentration to explosion-proof values, and then increasing the concentration of m due to natural influx up to values exceeding the upper explosive limit of methane.

This problem is also achieved by the fact that the methane atmosphere of isolated mining is pumped out, constantly maintaining a small excess gas pressure compared with atmospheric pressure on the earth's surface.

The applied method of preventing methane explosions in mines (Labor protection: Textbook for high schools / K.3. Ushakov, B.F. Kirin, N.V. Nozhkin and others. Edited by K.Z. Ushakov. M .: Nedra, 1986 - 624 p.) Provides for a constant supply of fresh air to the mine workings to reduce the concentration of methane emitted to values lower than the lower explosive limit. However, under conditions of high loads at the face and restrictions on the speed of air movement in mines, explosive accumulations of methane are often formed in mines. Sudden emissions of coal and gas, soufflare methane emissions, large-block collapse of roof rocks, etc. also contribute to this. In addition, the air supplied to the mine dilutes methane, which makes it difficult to use this combustible gas, for example, to produce heat and energy.

The known method of preventing methane explosions in mines (RU 2189448 C1 (Nosenko V.D. et al.), Published on September 20, 2002) provides for isolation of mine workings and an increase in their methane concentration to values exceeding the upper explosive limit. An increase in methane concentration occurs due to its separation from the mined coal, the worked out space and the host rocks. Methane explodes at its concentration in the air in the range of 5-15%. If the concentration of methane in the air exceeds 15%, then such a mixture does not burn and does not explode. However, when implementing the known method, there is a danger of explosion due to the formation of explosive accumulations of methane in the process of increasing methane concentration after isolation of mine workings.

To prevent the formation of explosive gas concentrations in the first stage after isolation of the mine workings, when there is an increase in methane content in the air, these mine workings are filled with inert gas, reducing the oxygen concentration to explosion-proof values. Then there is an increase in the concentration of methane due to its natural emission from the mined coal, the mined-out space and the surrounding rocks, but an explosive mixture is not formed due to the low oxygen concentration.

In order to use combustible gas, the evolved methane is pumped out. However, to prevent fresh air from entering isolated mines, they are constantly supported with a slight excess pressure of methane gas compared to atmospheric air pressure on the earth's surface.

The application of the proposed method will avoid the danger of the formation of explosive concentrations in existing mine workings. In the process of coal mining, a gas medium is formed in the mine workings, the methane content of which due to its constant emission reaches 100%, which will prevent the occurrence of endogenous and exogenous fires. Under the conditions of a well-formed explosion-proof atmosphere, mining conditions create an unlimited increase in the rate of coal mining.

The method is as follows.

Before the start of treatment or tunneling work in mines with intensive methane emission, the existing mine workings, into which methane can be released, are isolated from the influx of fresh air. Then the insulated volume is filled with an inert gas, for example nitrogen, from the condition of decreasing the oxygen concentration to explosion-proof values, for example, up to 8%. To deliver people and goods to isolated workings, special gateways are used. People work in a methane or inert gas environment in insulating breathing apparatus.

After reducing the oxygen concentration to a predetermined value, for example, less than 8%, treatment or sinking operations are carried out, accompanied by the release of methane. The methane concentration in the isolated volume begins to increase, and the oxygen content decreases. After the methane pressure in the isolated volume exceeds the atmospheric pressure on the earth’s surface, the methane mixture is pumped out of the isolated volume, provided that the excess gas pressure is maintained in this volume. As methane is released, its concentration in the isolated volume increases, reaching 100%. Evacuated methane is used, for example, to produce thermal and electrical energy in internal combustion engines and turbines.

In the created gas environment, due to the lack of oxygen, methane and coal dust explosions, endogenous and exogenous fires are impossible. The advantage of the proposed method is cost savings by reducing the cost of ventilation of mine workings, to prevent spontaneous combustion of coal, to conduct mining workings by reducing their cross section. There will be no need for preliminary degassing of coal seams. Under these conditions, the use of mine methane is greatly simplified.

The application of the proposed method allows to reduce the economic damage caused by methane explosions, to increase the safety of mining.

Claims (2)

1. A method of preventing methane explosions in mines, including isolating the mine workings in which methane is released from fresh air and increasing methane concentration by extracting it from the mined coal, the mined space and the surrounding rocks to values exceeding the upper methane explosive limit, differing the fact that after isolation of the mine workings they are filled with inert gas, reducing the oxygen concentration to explosion-proof values, and then increasing the methane concentration due to the natural influx to values exceeding the upper explosive limit of methane. 2. The method according to claim 1, characterized in that the methane atmosphere of the isolated openings is pumped out, constantly maintaining a slight excess gas pressure compared to atmospheric pressure on the earth's surface.