CN102242640A - Rapid outburst elimination method for cross cut coal uncovering in coal mine underground - Google Patents

Abstract

The rapid outburst elimination method for uncovering coal in Shimen underground coal mine includes the following steps: before the outburst coal seam is uncovered in Shimen, hydraulic fracturing drilling is arranged at a distance of 5-7m between the coal mining face in Shimen and the coal seam; the fracturing drilling is sealed. ; Use clean water to fracturing the fracturing borehole; the amount of injected water is determined according to the outburst prevention range; Drain out the hole through the slag discharge hole; construct drainage drilling in the Shimen coal mining face, seal the hole with polyurethane and carry out drainage, the length of the sealing hole reaches the top/bottom of the coal seam; inject high-pressure nitrogen or air into the fracturing hole, Observe the change of gas flow rate and concentration in the drainage hole. If the flow rate increases, stop the gas injection; Fracturing is performed again and high-pressure gas is injected to replace methane. The invention can not only speed up the coal removal speed of the Shimen working face, but also play the role of dust suppression and improve the working conditions of the tunneling working face.

Description

Quickly eliminate outburst method for uncovering coal at Shihmen in coal mine

technical field

The invention relates to a rapid outburst elimination method for uncovering coal at an underground stone gate in a coal mine. the

Background technique

Article 81 of the "Regulations on the Prevention and Control of Coal and Gas Outbursts" issued by the National Safety Production Supervision and Administration Department and the State Coal Mine Safety Supervision Bureau in August 2009 stipulates that "the outburst prevention measures for the coal mining face in Shimen include pre-extraction of gas, discharge of drilling holes , hydraulic punching, metal skeleton, coal solidification or other measures that have been proven effective by tests", "according to the rock formation conditions of the working face, the minimum normal distance between the coal mining face and the outburst coal seam is required when implementing the anti-outburst measures of the working face It is: 5m for pre-extraction of gas, discharge drilling and hydraulic punching, and 2m for metal skeleton and coal solidification. When the section of the shaft is large and the degree of rock fragmentation is high, the distance should be increased appropriately.” the

Although the "Regulations on the Prevention and Control of Coal and Gas Outburst" listed many methods and technologies for the outburst prevention measures of coal uncovering in Shimen, during the implementation process, due to the differences in the occurrence conditions of coal seams, one or several of these measures were not implemented. In the process, it is difficult to quickly eliminate the outburst, which affects the speed of coal removal in Shimen, which in turn affects the mining succession and safe production of the mine. the

Contents of the invention

The purpose of the present invention is to provide a rapid outburst elimination method for removing coal at the Shihmen underground coal mine, which can not only increase the coal removing speed of the Shihmen working face, but also play a role of dust suppression and improve the working conditions of the Shihmen working face. the

In order to achieve the above object, the present invention adopts the following technical scheme: the rapid outburst elimination method for uncovering the coal at the Shihmen underground of the coal mine, comprising the following steps: (1) Before the Shihmen is uncovered from the outburst coal seam, the vertical distance between the working face and the coal seam is 5-7 m Arrange hydraulic fracturing drilling holes at the location, and the number of drilling holes is determined according to the influence range of hydraulic fracturing drilling holes, the size of roadway section and the required outburst elimination range; the final hole of the drilling hole penetrates the roof/bottom of the coal seam and the drilling depth is not less than 0.5m; (2) To seal the fracturing drilling, use a high-pressure steel pipe with a pressure of not less than 15 MPa and high-strength cement above 425 to seal the hole. The length of the hole sealing is from the hole to the top/bottom of the coal seam; (3) Use clean water to counter pressure The injection water pressure can be determined according to the thickness of the overlying rock layer, the loss of the pipeline, and the compressive strength of coal and rock; the injected water volume is not less than 20m3/h; the injected water volume is determined according to the outburst prevention range, and the larger the outburst prevention range is required , the more water needs to be injected; (4) After the fracturing is completed, use high-pressure water to punch the hole, and use high-pressure water to flush the coal and rock blocks produced by the fracturing out of the hole; The safety production supervision and management department and the State Coal Mine Safety Supervision Bureau issued the "Prominent Regulations on Coal and Gas Prevention and Control" in August 2009. The construction drainage drilling is sealed with polyurethane and the drainage is carried out. The length of the sealing hole reaches the roof/bottom of the coal seam (6) In order to improve the drainage efficiency, inject high-pressure nitrogen or air into the fracturing hole, the pressure of nitrogen or air should not be less than 0.4MPa, observe the change of the gas flow rate and concentration in the drainage hole, if the flow rate increases, the gas injection can be stopped (7) When the drainage effect reaches the standard and the Shimen working face has no outstanding danger, excavation can be started; if the drainage effect is not good, fracturing can be implemented again and high-pressure gas can be injected to replace methane. the

In the step (2), the compressive strength of the high-pressure steel pipe is above 15 MPa, and the compressive strength of the high-strength cement after solidification is above 30 MPa. the

In the above step (3), the water injection volume is 2%~4% of the volume of the coal body within the fracturing range. When this amount of water is injected, it can be considered that the water injection is over; at the same time, the injection pump should be closely observed during the fracturing process. For pressure changes, once the fracturing of the water injection pump is found to have dropped by 30%, the injection volume should be increased by changing the gear of the water injection pump, and so on until the water injection design is completed. the

In the step (1), before the outburst coal seam is uncovered in Shimen, the hydraulic fracturing drilling is arranged at a vertical distance of 5 m from the working face to the coal seam. the

The present invention changes the current status quo of slow coal removal speed, large amount of drilling work, and inconvenient operation in Shimen by implementing technological steps such as pressing, punching, and driving (fracturing, punching, and gas driving) on Shimen, and can solve the problem of Shimen working face. Prominent problems such as high risk and difficulty in coal seam gas extraction. It can not only speed up the coal removal speed of the Shimen working face, but also play a role of dust suppression and improve the working conditions of the Shimen working face. the

Description of drawings

Figure 1 is a schematic diagram of the fracturing stage;

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is the schematic diagram of punching stage;

Fig. 4 is the schematic diagram of extraction stage;

Figure 5 is a schematic diagram of the gas purging stage.

Detailed ways

Embodiment: as shown in Fig. 1-5, a kind of method for rapidly eliminating outbursts of unearthing coal at Shihmen underground of coal mine comprises the following steps:

(1) Before the outburst coal seam is uncovered in Shimen, hydraulic fracturing drilling holes (5m are used in this example) are arranged on the working face at a distance of 5-7 m from the coal seam (vertical distance). The number of drilling holes depends on the impact of hydraulic fracturing drilling The scope, section size of the roadway and the required outburst elimination range are determined; the final hole of the drill hole penetrates the roof (bottom) of the coal seam and is not less than 0.5m.

Article 82 of the "Regulations on the Prevention and Control of Coal and Gas Outbursts" stipulates that "when pre-extraction and gas discharge drilling anti-outburst measures are adopted on the coal mining face in Shimen and vertical shafts, the diameter of the drilling hole is generally 75~120 mm. The coal mining in Shimen The drilling control range of the working face is: at least 5 m outside the contour line of the two sides and the upper part of the stone gate, and at least 3 m at the lower part. The drilling control range of the coal mining face of the vertical shaft is: the near-horizontal, gently inclined, and inclined coal seams are the contours around the shaft At least 5m outside the line; at least 5m outside the steeply inclined coal seam along both sides of the strike and along the inclined upper contour line, and at least 3m outside the lower contour line.”. the

Therefore, when fracturing is implemented, the control range required for fracturing should be the maximum: the two sides of the stone gate and the upper and lower contour lines should be at least 5 m. According to the previous experience of hydraulic fracturing drilling in coal seams, the effective radius of hydraulic fracturing is not less than 10 m. Therefore, even considering the size of the Shimen area and only constructing one fracturing hole in the middle of the Shimen, the impact of fracturing The range can also meet the predetermined requirements; of course, in order to make the outburst elimination range meet the requirements as soon as possible, it is also possible to arrange 2~3 fracturing holes to inject high-pressure water at the same time. the

(2) For fracturing drilling and sealing, use high-pressure steel pipes (compressive strength above 15MPa) and special cement (compressive strength above 30MPa after solidification) to seal the holes. The length of the sealing holes is from the hole to the top (bottom) of the coal seam plate;

The length of the sealing hole and the tightness of the sealing hole are directly related to the success or failure of the water injection. The length of the sealing hole should be maximized under the premise of not sealing the coal seam.

(3) Use clean water to fracturing the fracturing borehole. The injection water pressure can be determined according to the thickness of the overlying strata, the loss of the pipeline, and the compressive strength of the coal and rock; the injected water volume is not less than 20m3/h; the injected water volume is determined according to the outburst prevention range , the larger the outburst prevention range is required, the more water needs to be injected. the

The amount of water injection can be determined according to the degree of development of coal fractures and porosity within the range of outburst coal seams. Generally, it is 2% to 4% of the volume of coal within the range of fracturing. When this amount of water is injected, it can be considered that the water injection is over. . At the same time, during the fracturing process, it is necessary to closely observe the changes in the pressure of the injection pump. Once the fracturing of the water injection pump is found to have dropped by 30%, it is necessary to increase the injection volume by changing the gear of the water injection pump. Repeat this until the water injection design is completed. the

(4) After the hydraulic fracturing is completed, the slag discharge hole can be constructed around the fracturing hole, and the fracturing hole can be punched by using high-pressure pumps and other equipment, and the broken coal and rock mass after the fracturing is completed can be drained The slag hole and the fracturing hole punch out of the hole, and play the role of pressure relief and permeability enhancement of the coal body in front. the

(5) Drainage drilling shall be carried out in accordance with the "Regulations on Prevention and Control of Outbursts of Coal and Gas" at the coal mining face in Shimen, and the holes shall be sealed with polyurethane and drained, and the length of the sealed holes shall reach the bottom (roof) of the coal seam;

(6) In order to improve the extraction efficiency, inject high-pressure nitrogen or air into the fracturing hole, the nitrogen or air pressure is not less than 0.4MPa, observe the changes in the gas flow rate and concentration in the extraction hole, and stop the gas injection if the flow rate increases;

The high-pressure nitrogen cylinder can be transported to the underground, and gas can be injected into the fracturing hole through the pipeline. The operator should wear antifreeze gloves and masks during the gas injection to avoid harm to the body.

(7) When the drainage effect reaches the standard and there is no outstanding danger in the excavation face, excavation can be started. If the drainage effect is not good, fracturing can be carried out again and high-pressure gas can be injected to replace methane. the

The present invention proposes "hydraulic fracturing, punching, and nitrogen replacement" to remove coal outburst prevention measures in Shimen, in order to change the current status of slow coal removal in Shimen, large amount of drilling work, and inconvenient operation. the

Figure 1 is a schematic diagram of the fracturing stage. The fracturing boreholes 1 and 2 are constructed on the coal mining face 3 in Shimen, and high-pressure water is injected to fracturing the coal seam, which plays the role of opening coal seam cracks and fracturing the coal body. The fracturing hole length penetrates the coal seam, and the hole diameter is between 75 and 120mm. In order to ensure the smooth implementation of fracturing, the fracturing holes need to be sealed, and the compressive strength after sealing should not be less than 20MPa. Fig. 2 is a sectional view of A-A in Fig. 1, 4 is a stone gate, and 5 is a coal body. the

Figure 3 is a schematic diagram of the punching stage. After the fracturing is completed, the slag discharge holes 6 are constructed at different distances around the fracturing holes 1 and 2. After the construction is completed, the fracturing holes are flushed through the high-pressure water pump 8 and the water outlet pipe 7. The coal and rock blocks produced in the fracturing stage are flushed out of the hole through the slag discharge hole 6, so as to loosen the coal body, relieve pressure, and increase the air permeability of the coal body. the

Figure 4 is a schematic diagram of the drainage stage. After the punching is completed, 9 holes will be drained in the Shimen working face 3, and the slag discharge hole and the drainage hole will be sealed with polyurethane, and connected to the drainage system for drainage. the

Figure 5 is a schematic diagram of the gas purging stage. If the drainage effect is not good, the high-pressure nitrogen cylinder 11 can be used to purify the borehole through the gas purging pipe 10, and the nitrogen cylinder is connected to the borehole with a pipeline to start injecting into the borehole. Nitrogen drives the gas in the coal body to flow, making it easy to extract, and the extraction will be carried out after the gas purging is completed. the

Claims (4)

1. The rapid outburst elimination method for uncovering coal at the Shimen underground of the coal mine is characterized in that it includes the following steps: (1) Before the Shimen uncovers the outburst coal seam, a hydraulic fracturing drill is arranged at a vertical distance of 5 to 7 m from the working face to the coal seam. The number of drilled holes is determined according to the impact range of hydraulic fracturing drilling, the size of the roadway section and the required outburst elimination range; the final hole of the drilled hole penetrates the roof/bottom of the coal seam and the drilling depth is not less than 0.5m; (2) The fracturing drill For hole sealing, use high-pressure steel pipes with a pressure of not less than 15 MPa and high-strength cement above 425 grades to seal the holes. The length of the hole sealing is from the hole opening to the top/bottom plate of the coal seam; (3) Fracturing the fracturing drilling with clean water , the injection water pressure can be determined according to the thickness of the overlying rock layer, the loss of the pipeline, and the compressive strength of coal and rock; the injected water volume is not less than 20m3/h; the injected water volume is determined according to the outburst prevention range, and the larger the outburst prevention range is required, the more water injection is required (4) After the fracturing is completed, use high-pressure water to punch the hole, and use high-pressure water to flush the coal and rock blocks produced by the fracturing out of the hole; (5) According to the national safety production supervision and management department, In August 2009, the National Coal Mine Safety Supervision Bureau issued the "Regulations on the Prevention and Control of Outbursts of Coal and Gas" in the construction of drainage drilling holes, which are sealed with polyurethane and drained. The length of the sealing holes reaches the roof/bottom of the coal seam; (6) to improve Drainage efficiency, inject high-pressure nitrogen or air into the fracturing hole, the nitrogen or air pressure is not less than 0.4MPa, observe the change of gas flow and concentration in the drainage hole, if the flow rate increases, the gas injection can be stopped; (7) When pumping When the mining effect reaches the standard and the Shimen working face has no outstanding danger, excavation can be started; if the extraction effect is not good, fracturing can be carried out again and high-pressure gas can be injected to replace methane. 2. The rapid outburst elimination method for uncovering coal at an underground stone gate in a coal mine according to claim 1, characterized in that in the step (2), the compressive strength of the high-pressure steel pipe is above 15MPa, and the high-strength cement can resist compression after solidification The strength is above 30MPa. 3. The rapid outburst elimination method for uncovering coal at the Shihmen underground of a coal mine according to claim 1 or 2, characterized in that: in the step (3), the water injection volume is 2% to 4% of the volume of the coal body within the fracturing range %, when this amount of water is injected, it can be considered that the water injection is over; at the same time, during the fracturing process, the pressure change of the injection pump should be closely observed. Increase the injection volume bit by bit, and repeat this until the water injection design is completed. 4. The rapid outburst elimination method for uncovering coal at an underground stone gate in a coal mine according to claim 3, characterized in that in the step (1), before the outburst coal seam is uncovered at the stone gate, the vertical distance between the working face and the coal seam is 5 A hydraulic fracturing borehole is arranged at m.

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