RU1789031C - Method for control of gas emission in pillarless mining of extraction field by stoop method - Google Patents

Abstract

Usage: gas evolution control in mining areas. SUMMARY OF THE INVENTION: A mining field is prepared for mining by twin drifts. The ventilation output of the next extraction column is malfunctioned with an unsupported conveyor output of the spent column. Before the start of the cleaning recess, insulating jumpers are installed in failures. A pipeline is laid in the ventilation outlet, one end of which is connected to the inlet by the gas suction unit of the installation, and the other is inserted behind the bridge in a fault ahead of the lava. The gas-air mixture from the worked-out space is discharged in the direction of movement of the treatment face in the event of a malfunction and a pipeline laid in the ventilation outlet. 2 ill. ate

Description

FIELD: mining. SUBSTANCE: invention can be used in gas emission control in mining areas during aimless mining of coal seams.

There is a known method for controlling gas evolution with an isolated methane discharge from an exhausted space through an unsupported ventilation outlet.

The disadvantages of this method are;

preparation of the excavation floor for mining is carried out by single drifts, which is associated with high costs (protection of workings with rubble strips) for maintaining and maintaining the workings in the worked out space for reuse;

ventilation according to a flow-through scheme with the supply of fresh air for production at the contact with the exhausted space,

due to large air leaks into the exhausted space;

the presence of a flank hole for the removal of methane-air mixture (MVS);

limiting the possibility of using coal that is dangerous for spontaneous combustion during mining, which is associated with additional costs for the prevention of endogenous fires and difficulties in regulating air leaks through the worked out space;

when MVS is withdrawn from the worked-out space in the opposite direction to the side of the treatment plant, it is difficult to satisfy the condition that the air leakage does not exceed 30% of the amount of air entering the extraction section.

Closest to the invention and selected as a prototype is a method of controlling gas evolution from VI

00 s

about

: CO

Ј

working space using drainage workings or workings of previously worked lavas. The known method consists in preventing the formation of dangerous accumulations of methane at the interface of the lava with ventilation production during mining of medium-power formations, including those prone to spontaneous combustion. MVS is discharged by a drainage outlet, which is carried out 5-10 m from the ventilation outlet during the preparation of the excavation floor and is connected through failures to it at certain distances, in which insulating jumpers are erected before the excavation begins. The cross section of the drainage in the light should be at least 3.7 m, and the disruption should be at least 3 m2.

A mine can also be used to remove the gas, which is retained after mining the overlying lava. Improving the efficiency of drainage workings is achieved by removing the MVS using a centrifugal fan (gas-suction unit GOU) through a pit or a large-diameter well (0.5-0.6 m) drilled from the surface.

However, the use of the existing gas evolution control method is not contemplated for aimless mining of the extraction fields. The disadvantages include the need for additional (drainage) mining or maintaining and maintaining the latter in the mined space during mining of the overlying lava, which is associated with significant material costs, while it is practically impossible to maintain the required geometric parameters of the supported mine and provide the necessary air flow for ventilation due to mine depression, which is often the reason for the accumulation of methane with a dangerous concentration. In addition, the withdrawal of the MF from the space mined out within the limits of the worked out mining column to the side opposite to the movement of the treatment face creates certain difficulties when maintaining geometrical and aerodynamic parameters, especially on formations prone to spontaneous combustion. A significant drawback is the need to drill large (0.5-0.6 m) diameter wells to draw the MFW to the surface. For a mountainous surface, or even slightly swampy, this condition is practically not feasible.

The aim of the invention is to prevent dangerous accumulations of methane at the interface of the mine with ventilation and unsupported during aimless mining of excavation fields without maintaining the excavations of previously worked lavas in the excavated space (without additional drainage excavations) and eliminating the above-mentioned disadvantages.

The goal is achieved in that

in the known method of controlling gas evolution, including preparing the extraction fields for mining by twin drifts, sequentially diluting the hazards by the sources of their entry, ventilating the treatment work section between the conveyor and ventilation drifts due to the mine depression, removing the air stream emitted from the cleaning production by the ventilation production guarded

pillars on both sides, in the direction of movement of the treatment face, the MVS outlet for drainage with the help of GOU (centrifugal CV fan), the prevention of dangerous accumulations of methane on

The conjugation of the treatment plant with the ventilation and the unsupported one is carried out due to the fact that part of the methane with a dangerous concentration is discharged into the worked out space of the mine

of the extraction column into the mined-out space of the overlying worked-out mining section using the methane's own lifting force and the presence of the aerodynamic connection generated

spaces, which is provided by aimless mining of the excavation field (without leaving artificial obstacles in the worked-out space - pillars of coal or rubble strips), another part together with

MVS is diverted to the section of the mine production line, which is in the inter-track direction, due to the depression created by the GOU (CV), towards the unsupported production and is diverted in isolation along

a section of unsupported production through the lava leading upstream hole (well) connecting the unsupported production with the ventilation one, and a pipeline laid along the ventilation development, the suction part of which is led at one end by a jumper isolating the unsupported production from the ventilation in the leading lava failure (or connects to the leading mouth

well, connecting the unsupported production with the ventilation), the other end is connected to the GOU (CV), using the GOU (CV) within the worked out extraction column in the direction

coinciding with the direction of movement of the treatment face.

The fundamental difference between the proposed method of gas evolution control from the existing one is that the MVS is discharged within the extraction column in the direction of the treatment face movement, and not in the opposite direction, while hazardous accumulations of methane are prevented from interfacing the production unit with ventilation and unsupported by preventing methane from entering the treatment space due to its free flow into the overlying waste space (which is ensured by the presence of aero ynamic communication goaf) and intense motion of the air flow on the cleaning portion to generate mezhshtrekovom entirely by the discharge voltage generated on the mated cleaning produce an unsupported depression SEI (CV).

Using the inventive gas emission control method will provide the following advantages over existing methods:

mining of excavation fields without pillars of coal left in the worked out space, which eliminates coal losses and increases the reliability of endogenous fire safety;

to exclude the costs of additional drainage workings or to maintain and maintain the latter in the worked out space, in turn, eliminating the need to maintain workings will reduce the time for end operations and thereby increase the load on the working face or free up additional numbers;

the ventilation of the excavation sections is carried out on the front bremsbergs (corners), which allows to significantly reduce leakage through the worked out space and increase the fire safety of formations prone to spontaneous combustion;

there is no need for flanking workings or for drilling large diameter wells from the surface, which is associated with high capital costs;

the application of the method is practically not limited to mining conditions;

provides high and reliable safety of mining operations;

significantly improves the aerodynamic characteristics of ventilation networks, allows you to control the distribution of air over a wide range.

In FIG. 1 shows a method for controlling gas evolution using a GOU; in FIG. 2

A specific embodiment.

As shown in FIG. 1 option, according

as lava 1 moves, that part of the conveyor drift 2 that goes into the worked out space 3 is fully or partially extinguished (which depends mainly on the strength of the enclosing rocks and

0 mining and geological parameters of the excavation site).

With stable host rocks, the mine fastening is removed in whole or in part (due to production necessity and adopted mining technology), and with unstable host rocks it is reinforced with fires (to increase the efficiency of gas extraction

- not shown in the drawing).

0 At the end of lava 1 mining, it is isolated from the active workings by jumpers 4 and 5 in the zone of the security pillar 6.

To implement the method (Fig. 1) during the preparation of the excavation section 8

5 when conducting ventilation workings 9, the latter is connected at certain distances to unsupported production 2 faults 10, in which isolating jumpers 14 are built before the start of the cleaning excavation (faults 10 can be replaced by boreholes drilled in the inter-track pillar 17 from generation 9 into generation 2, which before the start of the cleaning excavation is blocked by plugs - on

5 is not shown). A hard pipe 15 is laid along the ventilation outlet 9, which is connected on one side with the suction of the GOU 11 and, on the other, is led over the jumper 14 in the first

0 output 16 fault 10 (or connected to the mouth of the first well from the lava - not shown in the drawing),

In the same period, an electric machine chamber is installed in which

5, the GOU fan 11 and the inlet are connected to the rigid pipe 15. A flexible (or rigid) discharge pipe 12 is connected to the discharge side 12. The end of the pipe 12 through which the MVS is discharged is introduced into the mixing chamber 13 and is equipped with an elbow providing the MVS from the pipeline at an angle of 45 ° to the direction of the main ventilation flow. Mixing chamber

5 to 13 is a portion of a workway sewn with a continuous longitudinal partition of non-combustible material. The length of the mixing chamber is 5-6 m, the width is at least 1.5 m. The entrance to and exit from the chamber is enclosed by metal bars. Production in

the chamber construction site, 5 m long on both sides of it, shall be secured with non-combustible support. When methane is removed to the surface, measures are taken to ensure its safe release into the atmosphere. When the treatment plant 16 approaches the nearest fault 10 (to the well), the pipeline 15 is started through the jumper of the next leading fault (connected to the next leading well), and in the section between the faults 10 (wells) it is dismantled.

The optimal distance between faults 10 (boreholes) and the parameters of the isolated MFW discharge to the mine workings or to the surface are determined by calculation.

The method is carried out as follows.

Fresh air from the central Bremsbergs (slopes) 18 enters the conveyor drift 19 to the treatment mine 16. Part of the air (80-90%) enters the lava 16, the other part of the air, together with leaks 20, into the exhausted space 21, displaces the methane 22 from the lava 16 Under the influence of the mine shaft depression, own lifting force, air leaks 20, the presence of free aerodynamic communication between the exhausted spaces 21 and 3, methane 22 is discharged into the overlying exhaust space 3 and, due to the vacuum created by the depression, GOU 11 is directed to unsupported production 2.

Part of the air entering the lava 16 is directed to the section of the mine workout 23, located in the inter-track pillar 17 with the help of the depression created by GOU 11 and discharged to the unsupported mine 2. It is mixed with methane 22 to form MBC 24 with a dangerous concentration of methane. it is diverted in isolation from the outlet 2 and the pipeline 15 by the GOU 11 through the mixing chamber 13 (or directly to the day surface - not shown in the drawing) into a common downstream stream of the mine or excavation section.

Another part of the air, which is the difference between the amount of air entering the lava 16 and discharged from the unsupported mine 2 using GOU 11, with the allowable methane content due to the mine shaft depression, is diverted through the ventilation mine 9 to the common downstream stream of the excavation section and the shaft.

The air flow rate for ventilation of the section of the mine workings 23 is determined from the condition that the concentration of methane at the interface of the lava 16 with an unsupported mine 2 is not more than 1% by the formula

n UR U Kn

QoTB --- C 1

where is qotb. - the required flow rate of air discharged from unsupported production, m / min;

1vp - gas evolution from the generated

space (determined by forecast, from the actual gas balance of an existing or similar extraction site), m / min

 - permissible methane content

in discharged into unsupported air production;

С0 - methane content in the air stream entering the extraction section,%. The resulting air flow rate is checked against the permissible air velocity.

The direction of air movement in the ventilation opening 9 and the conveyor 19 may differ from that shown in FIG. 1,

which depends on the order of ventilation of the treatment mine 16 (upward or downward ventilation) and the location of the mine with a common air stream.

PRI me R. In July 1990, an experimental testing of the proposed method for controlling gas evolution in lava 4-7-17 was carried out at the Raspadsk mine of the USSR Unitary Enterprise, (Fig. 2). The length of the lava was 120

m, the mine working area between the ventilation and unsupported 20 m, the column length is 700 m, the thickness of coal packs is 4-4.5 m, the dip angle of the formation is 6-8 °, the natural gas content is 12-15 m3 / t, fortress

host rocks 6–9 on the prof. A step of the conov, the management of the roof is a complete collapse.

In the process of mining the extraction column 1 of the conveyor belt, the production 2 was preserved

for subsequent use in mining by lava 3. However, during the mining of lava 3, due to increased mountain pressure, partial heaving of the soil and other natural factors, the preserved output 2 could not be fully preserved and maintained in the area of 560-700 m from the central slope 4, as a result of which the production was completely crushed, and in a section of 80-560 m only

15-20% and amounted to 2-2.5 m2.

With this mining situation, lava 3 received an average of 600-650 m3 / min of air, which almost all (90-95%), having ventilated lava 3, is discharged through ventilation mine 8 with a methane content of 0.6-0.8% . Gas evolution in the extraction section was 5-6 m3 / min. The air almost did not pass through the purification section 9, as a result of which methane accumulated in this section and in conjunction with unsupported production 2, the concentration of which varied from 0.6% at the ventilation output of 8 to 2% or more at the end section 10 , which accordingly led to the triggering of automatic gas protection and frequent halting of coal mining operations.

Then, following an example similar to FIG. 1, GOU 5 (centrifugal fan VMTsG-7) was mounted, a pressure flexible ventilation pipe 6 was connected, and through a fault it was brought into the mixing chamber 7, which is equipped with a common outlet stream of the extraction section.

Immediately after switching on GOU 5, the methane content at the outlet of the mixing chamber 7 increased to 2.5-3%, and at 15-20 m at point 11 from 0.5-0.6% to 1.0-1.5%, at the end section 10, it fell to 0.2-0.4% at an air flow rate of 280-300 m3 / min. 3-4 hours after the aerodynamic parameters of the excavation section were stabilized, the following results were established: the incoming air to the lava 3 was 900-1000 m / min, 600-700 m3 / min with a methane content of 0.2-0 were discharged from the ventilation output 8 , 4%, in the area of treatment output 9 300-350 m3 / min with a methane content of 0.3-0.4%. At the exit of the mixing chamber 7, the methane content was 0.4-0.6%. The total gas evolution in the area was less than 5 m3 / min. In this mode, the extraction column was worked out over a length of 140 m. Moreover, over the entire period, the permissible methane content was never exceeded. The increase in air flow in the area indicates a decrease in the total aerodynamic resistance of the ventilation

network, which is very important when working out coal prone to spontaneous combustion. And although it was possible to significantly reduce the total air flow in the area, such experiments were not conducted. The measures taken made it possible to significantly improve the gas situation and carry out coal mining operations in the regime without reducing production. As a result, the monthly movement of the stope was 140 m or more than 90 thousand tons of coal.

Claims (1)

SUMMARY OF THE INVENTION A method for controlling gas evolution in an aimless mining of a mining half-pillars, including the preparation of the excavation floor for mining by twin drifts, the ventilation of the sewage treatment area between the conveyor and ventilation drifts due to the mine shaft depression, removal of the air stream emanating from the mine working outlet through the ventilation mine, guarded by pillars on both sides, and methane-air mixture removal using a gas suction unit, characterized in that, in order to prevent dangerous accumulations of methane at the interface of the treatment plant with the ventilation and unsupported production, the ventilation production of the next extraction column is connected by failures to the unsupported conveyor production of the spent column, and insulating jumpers are installed in the failures before the treatment excavation begins and a pipeline is laid in the ventilation outlet, one end of which is connected to the inlet of the gas-suction unit, and the other end is connected to an insulating jumper in a fault ahead of the lava, in this case, the gas-air mixture is discharged from the worked-out space by the aforementioned fault and the pipeline laid along the ventilation working out in the direction of movement of the treatment face.