Press-in ventilation shallow buried coal seam well vertical air leakage accurate control method

Abstract

The invention provides an accurate control method for vertical air leakage of a press-in ventilation shallow buried coal seam well. The method comprises the steps that 1, mine ventilation parameters are obtained, and the air leakage rate, the air leakage rate, the air demand and the like are calculated; 2) judging an air leakage position according to the air leakage parameters; and 3) accurately taking control measures for air leakage above and below the well. The method comprises the following steps: firstly, calculating parameters such as internal and external air leakage of a mine, preliminarily judging air leakage sites according to the air leakage rate and the required air volume, and then judging measures to be taken according to specific rules of each air leakage site, so that the process of judging different positions and taking corresponding measures according to the parameters such as the air leakage rate, the air leakage rate and the required air volume of the mine is realized. On the basis, air leakage blocking measures are implemented more efficiently and accurately through judgment of air leakage inside and outside the mine and an accurate air leakage control method, and systematic guidance is provided for prevention and treatment of air leakage from the upper portion and the lower portion of the press-in type ventilation shallow-buried coal seam well.

Description

Technical Field

[0001] The invention relates to a method for accurately controlling upper and lower air leakage in a pressure-ventilated shallow-buried coal seam well, belongs to the technical field of coal mine air leakage blocking and fire prevention, and is a comprehensive control technology for upper and lower air leakage in pressure-ventilated mines. Background Art

[0002] During the mining process of shallow, spontaneously combustible, close-range coal seams, the mining of the lower coal layer is affected by the overlying goaf, resulting in extremely good development of air leakage fissures. Most shallow mines do not have a curved lower layer zone, and the fracture zone directly penetrates to the surface, continuously supplying oxygen to the remaining coal and coal pillars in the goaf, increasing the probability of coal spontaneous combustion and endangering the safe production of coal mines.

[0003] Mine ventilation is divided into two modes: extraction ventilation and pressure ventilation. For the extraction ventilation mode, the external air leakage direction of the goaf is from the surface to the return air lane. The air leakage convergence under this mode is relatively simple, and the air leakage volume can be accurately grasped. On the contrary, the external air leakage direction of the goaf is from the air intake lane to the surface. The range of cracks developed to the surface is large, and it is difficult to measure the actual air leakage volume. Traditionally, there is no reasonable and standardized step for goaf air leakage control. In addition, due to the particularity of pressure ventilation, the air leakage control effect is not ideal, and it is impossible to accurately and effectively prevent the spontaneous combustion of coal in the goaf. Therefore, for the air leakage prevention and control in the process of multiple overlapping disturbance mining of shallow buried and self-igniting close-range coal seams with pressure ventilation, a set of reasonable and standardized comprehensive control methods for upper and lower well air leakage are proposed, and air leakage blocking measures are implemented more efficiently and accurately, providing a theoretical basis for the formulation of upper and lower well air leakage prevention and control plans for shallow buried coal seams with pressure ventilation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for accurately controlling upper and lower air leakage in a pressure-ventilated shallow buried coal seam well, so as to solve or alleviate the problems existing in the above-mentioned prior art methods.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The present invention provides a method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-in ventilation, comprising the following three steps:

[0007] S1 obtains mine ventilation parameters and calculates air leakage, air leakage rate and required air volume, etc.;

[0008] S2 determines the air leakage location according to the air leakage parameters;

[0009] S3 takes precise measures to control air leakage above and below the well.

[0010] The step S1 of obtaining the mine ventilation parameters, calculating the air leakage volume, air leakage rate and required air volume, etc., comprises the following steps:

[0011] S11 uses the measured mine ventilation ten-day report and ventilation facility leakage to calculate the mine's external and internal air leakage. The calculation formula is as follows:

[0012] (1)

[0013] Where: Q 外漏 ——Total air leakage outside the mine, m 3 / min;

[0014] Q 主通 ——Total working air volume of main ventilators in the mine (location is at the ventilator wind tunnel), m 3 / min;

[0015] Q 实测 ——Total measured air volume of the return air shaft (the location is the total return air measurement station), m 3 / min;

[0016] (2)

[0017] Where: 外漏 ——Total air leakage rate outside the mine, %;

[0018] (3)

[0019] Where: Q 内漏 ——Total air leakage inside the mine, m 3 / min;

[0020] Q 实进 ——Actual total air intake volume of the mine, m 3 / min;

[0021] Q 有效 ——Effective air volume in the mine, m 3 / min;

[0022] (4)

[0023] Where: 内漏 ——Total air leakage rate inside the mine, %;

[0024] S12 calculates the required air volume Q for the excavation and coal mining face based on the gas outflow, meteorological conditions, explosive quantity, number of people, number of vehicles, etc. 掘需 and Q 采需 .

[0025] Determining the air leakage position according to the air leakage parameters in step S2 includes the following steps:

[0026] S21 Mine external air leakage rate 外漏 When it is > 5%, the air leakage location is the wellhead and the surface cracks; 外漏 When it is less than 5%, the underground air tightness is good and the effect of air leakage can be ignored;

[0027] S22 Mine Internal Air Leakage Rate 内漏 > 5%, the air leakage location is the goaf and ventilation facilities; the air leakage rate inside the mine 内漏 < 5%, the working surface has good sealing performance and the impact of air leakage can be ignored.

[0028] The above-mentioned step S3 accurately adopts the above-ground and below-ground air leakage control measures, including the following steps:

[0029] When there is air leakage outside the S31 mine, the wellhead fan and its auxiliary devices need to be more tightly sealed. For surface cracks, use a tape measure and drone aerial photography to statistically analyze the evolution of the type, width and depth of surface cracks. For graben-type and collapse-type cracks, mechanical backfilling + hydraulic flushing of the surface is adopted. No measures are required for other cracks.

[0030] S32 When there is air leakage inside the mine, when the effective air volume Q 工作面有效 >Q 掘需 +Q 采需 When the air leakage in the goaf is stable, perlite is piled up intermittently in the corners to plug the leakage; when the air leakage is unstable, perlite is piled up immediately in the corners to plug the leakage; when the monitoring system finds abnormal temperature and gas concentration, air adjustment measures and fire prevention and extinguishing technology should be taken immediately; when the temperature and gas concentration are normal, the plan should be implemented normally; ventilation facilities need to strengthen daily management and improve the quality of setting. 工作面有效 掘需 +Q 采需 When the air volume on the working face is insufficient, production should be stopped and the cause should be thoroughly checked.

[0031] Preferably, in step S1, the mine air leakage is divided into internal air leakage and external air leakage. According to the law of conservation of energy, the total air intake volume = total air leakage volume + total return air volume, and the total air leakage volume = internal air leakage + external air leakage. The internal air leakage will flow to the goaf and then flow back to the working face and the goaf through the corresponding wind flow trajectory, which will not affect the total return air volume. For forced ventilation, external air leakage will cause the air volume in the return air channel to decrease.

[0032] ​Preferably, in step S2, the air leakage rate of the mine fan does not exceed 5%. The "Safety Regulations for Coal Mines" (2022) stipulates that the main ventilation fans must be installed on the ground, and the wellheads equipped with ventilation fans must be tightly closed. The external air leakage rate shall not exceed 5% when there is no lifting equipment, and shall not exceed 15% when there is lifting equipment.

[0033] Preferably, in step S3, the surface cracks are divided into four types: graben type, tensile type, opening type and collapse type. The relationship between the four types of cracks is as follows: with the mining of shallow buried coal seams and the movement of strata, tensile cracks and opening cracks with a width of less than 10 cm are first formed on the surface due to the cantilever beam structure. With the breaking of the cantilever beam structure, tensile cracks and opening cracks with a width of less than 10 cm will close, and graben type and collapse type cracks will appear within a range of 10 to 20 m lagging behind the surface of the working surface, and there is a possibility of air leakage.

[0034] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] The present invention provides a method for accurately controlling air leakage above and below a shallow buried coal seam well with pressure-in ventilation. First, the air leakage volume, air leakage rate, and required air volume are calculated using the ventilation parameters of the mine. Then, the air leakage location is determined by combining the internal and external air leakage rates, effective air volume, and required air volume of the air leakage parameters. Then, the specific rules of different air leakage locations are combined to determine the corresponding measures to be taken at the air leakage points such as the wellhead, surface fissures, and goafs. Based on this, the relationship between mine ventilation and internal and external air leakage is used to accurately identify the type of air leakage that exists, and corresponding measures are taken in a targeted manner. Mine leakage blocking measures are implemented more accurately, efficiently, and energy-savingly, providing systematic guidance for the prevention and control of air leakage above and below a shallow buried coal seam well with pressure-in ventilation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-type ventilation according to the present invention;

[0037] Figure 2 This is a flow chart of the method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-type ventilation according to the present invention;

[0038] Figure 3 It is a schematic diagram of the graben fissure in the method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-type ventilation according to the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with the embodiments and drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be understood that terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inside” and “outside” indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device, component or structure must have a specific direction, be constructed or operate in a specific direction, and should not be understood as a limitation on the present invention.

[0041] The specific implementation method of the present invention will be further described below in conjunction with the accompanying drawings.

[0042] Engineering background: A certain pressure-ventilated mine has one air intake shaft with two channels, and the return shaft has one return shaft, one return inclined shaft, and one return exhaust hole. The main mining areas are 12 and 22 coal seams. The burial depth of 12 coal is 73~115 m and has been mined out. The burial depth of 22 coal is 84~134 m, and the thickness of the coal seam is 3.5~4.3 m. There are two working faces arranged in two panels, namely 209 and 206 working faces. The overlying 12 coal goaf and 22 coal are in an oblique state. Due to the pressure-ventilated mine, there are also overlying goafs, and the surface cracks are wide, which leads to the problem of long-term air leakage and plugging difficulties. In addition, the air leakage positions are disordered and the measures are used arbitrarily, which seriously threatens the safety production of the mine.

[0043] In order to solve this problem, the method of the present invention is used to accurately seal the air leakage above and below the well. The specific steps are as follows:

[0044] Calculate Q using mine ventilation parameters 外漏 =23088-21177=1911 m 3 / min, 外漏 =1911÷23088=8.28%, Q 内漏 =22655-21409=1246 m 3 / min, 内漏 =1246÷22655=5.50%, Q 掘需 =340+320+300=960m 3 / min, Q 采需 =1109+1203=2312 m3 / min, Q 工作面有效 =430+400+410+1356+1434=4030. The internal and external air leakage rates of the mine are both greater than 5%, and the mine has internal and external air leakage.

[0045] When the mine external air leakage rate 外漏 > 5%, the air leakage location is the wellhead and the surface cracks. When the air leakage rate inside the mine is 内漏 > 5%, the leakage locations are goaf and ventilation facilities.

[0046] After the above steps, it is necessary to take measures to control air leakage above and below the mine. The specific steps are as follows:

[0047] When there was air leakage outside the mine, we checked that the sealing of the wellhead fan and its accessories was good; for the surface cracks, we used a tape measure and drone aerial photography to statistically analyze the surface cracks and found that there were a large number of graben cracks and collapse-type cracks with cracks larger than 10 cm, indicating that external air leakage mainly occurred in surface cracks. For graben-type and collapse-type cracks, we adopted surface mechanical backfilling + hydraulic flushing, and no measures were needed for the remaining cracks.

[0048] The statistical analysis of surface cracks is as follows: crack observations were carried out on the surface, and the type, direction, and width of surface cracks were counted using the mine surface two-dimensional positioning system and a tape measure. The statistical results of crack width within 200 m above the working face are shown in Table 1. Among them, the graben-type fissures are located just above the middle of the goaf, slightly lagging behind the working face by 10-20 m, parallel to the inclination of the working face, and the crack width is 10-20 cm; the collapse-type fissures are located on the inner surface above the two lanes of the working face, 30-35 m away from the inner side, parallel to the direction of the working face, and the crack width is 1-3 m; the opening-type fissures are formed due to the sinking of the middle of the goaf, which causes the surface at the edge of the goaf to be subjected to a large tensile effect. They are often distributed in the front section of the collapse-type fissures and the two wings of the graben-type fissures, with crack widths of 1-2 m and 1-5 cm respectively; the number of tensile-type fissures is large, the distribution range is wide, and they appear a distance ahead of the working face. Most of them are parallel to the working face, and the crack width generally does not exceed 20 cm. For the collapse-type and graben-type fissures with a width greater than 10 cm, the measures of surface loess backfilling and hydraulic crack flushing are taken.

[0049]

[0050] When there is air leakage inside the mine, the total effective air volume Q of the working face 工作面有效 >Q 掘需 +Q 采需When (4030>960+2312), if the air leakage in the goaf and return air tunnels is stable, perlite should be piled at intervals of 100 m in the corners (the spacing of the connecting tunnels is 100 m) to stop the leakage; if the air leakage is unstable, perlite should be piled immediately in the corners to stop the leakage; if the monitoring system finds abnormal temperature and gas concentration, air adjustment measures and fire prevention and extinguishing technology should be taken immediately; when the temperature and gas concentration are normal, the plan should be implemented normally; ventilation facilities need to strengthen daily management and improve the quality of installation.

[0051] Monitor the temperature and gas concentration in the goaf. By burying optical fibers and bundle tubes near the air inlet and return sides of the goaf, the temperature and gas concentration changes in the goaf are monitored. The temperature is below 30°C and the gas concentration does not show the natural characteristic gas of coal, so there is no need to take measures to reduce the air volume of the working face.

[0052] At this point, those skilled in the art should recognize that, although the exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the contents disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-type ventilation, comprising the following steps: S1: Obtain mine ventilation parameters and calculate air leakage, air leakage rate and required air volume; S2: Determine the air leakage location according to the air leakage parameters; S3: Accurately take measures to control air leakage above and below the well.

2. According to claim 1, a method for accurately controlling air leakage in a shallow buried coal seam well with pressure-in ventilation, characterized in that: In step S1, the mine ventilation parameters are obtained, and the air leakage volume, air leakage rate and required air volume are calculated, including the following steps: S11 uses the measured mine ventilation ten-day report and ventilation facility leakage to calculate the mine's external and internal air leakage. The calculation formula is as follows: （1） Where: Q 外漏 ——Total air leakage outside the mine, m 3 / min; Q 主通 ——Total working air volume of main ventilators in the mine (location is at the ventilator wind tunnel), m 3 / min; Q 实测 ——Total measured air volume of the return air shaft (the location is the total return air measurement station), m 3 / min; （2） Where: 外漏 ——Total air leakage rate outside the mine, %; （3） Where: Q 内漏 ——Total air leakage inside the mine, m 3 / min; Q 实进 ——Actual total air intake volume of the mine, m 3 / min; Q 有效 ——Effective air volume in the mine, m 3 / min; （4） Where: 内漏 ——Total air leakage rate inside the mine, %; S12 calculates the required air volume Q for the excavation and coal mining face based on the gas outflow, meteorological conditions, explosive quantity, number of people, number of vehicles, etc. 掘需 and Q 采需 .

3. The method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-type ventilation according to claim 2 is characterized in that: In step S2, the air leakage position is determined according to the air leakage parameters, including the following steps: S21 Mine external air leakage rate 外漏 When it is > 5%, the air leakage location is the wellhead and the surface cracks; 外漏 When it is less than 5%, the underground air tightness is good and the effect of air leakage can be ignored; S22 Mine Internal Air Leakage Rate 内漏 > 5%, the air leakage location is the goaf and ventilation facilities; the air leakage rate inside the mine 内漏 <5%, the working surface has good sealing performance and the impact of air leakage can be ignored.

4. The method for accurately controlling upper and lower air leakage in a shallow buried coal seam well with pressure-type ventilation according to claim 2 is characterized in that: In step S3, accurate measures are taken to control air leakage above and below the well, including the following steps: When there is air leakage outside the S31 mine, the wellhead fan and its auxiliary devices need to be more tightly sealed. For surface cracks, use a tape measure and drone aerial photography to statistically analyze the evolution of the type, width and depth of surface cracks. For graben-type and collapse-type cracks, mechanical backfilling + hydraulic flushing of the surface is adopted. No measures are required for other cracks. S32 When there is air leakage inside the mine, when the effective air volume Q 工作面有效 >Q 掘需 +Q 采需 When the air leakage in the goaf is stable, perlite is piled up intermittently in the corner to plug the leakage; when the air leakage is unstable, perlite is piled up immediately in the corner to plug the leakage; when the monitoring system finds abnormal temperature and gas concentration, air adjustment measures and fire prevention and extinguishing technology should be taken immediately; when the temperature and gas concentration are normal, the plan is implemented normally; Ventilation facilities need to strengthen daily management and improve the quality of setting; when the effective air volume Q 工作面有效 掘需 +Q 采需 When the air volume on the working face is insufficient, production should be stopped and the cause should be thoroughly checked.​

Images