CN104265353A - Method for preventing gas from exceeding limit in early mining period of fully mechanized top-coal caving face of hard roof - Google Patents

Abstract

The invention discloses a method for controlling the overrun of gas in the initial mining period of a hard roof fully mechanized caving surface, adopting a "U+I" type ventilation method, including arranging an inner staggered tail lane (3) inside the return air lane (2), and In the air inlet lane (1), the return air lane and the internal cross-tail lane, arrange the bedding drilling to extract the gas in the coal seam, and arrange the direction high drainage lane (4), the rear false high drainage lane (5), the low inclined high drainage The gas in the adjacent layer is extracted from the roadway (6), and the problem of gas exceeding the limit in the initial mining period of the fully mechanized caving face with a hard roof is comprehensively controlled in conjunction with the pre-splitting blasting technology of the craft roadway (8) and the reasonable advancing speed of the working face. This method of controlling the gas overrun in the initial mining period of the hard roof fully mechanized caving face focuses on solving the problem that the hard roof does not collapse during the initial mining period. The poor mining effect and gas influx into the working face from adjacent layers caused the gas to exceed the limit, which provided a guarantee for the safe production of the fully mechanized caving face during the initial mining period.

Description

A method for controlling the gas over-limit in the initial mining stage of fully mechanized caving face with hard roof

technical field

The invention relates to a method for controlling gas overrun in fully mechanized caving faces, in particular to a method for controlling gas overrun in fully mechanized caving faces with hard roofs at the initial mining stage, and is suitable for gas at the initial mining stage of fully mechanized caving faces with hard roofs that do not collapse High-gas mines with severe overruns belong to the field of mine gas control.

Background technique

Coal mine gas refers to a large amount of gas generated by plants in the process of coal formation, also known as coalbed methane, which is stored in the pores and fissures of coal seams or rock formations. Gas exists in a free state and an adsorbed state in coal bodies or surrounding rocks. Gas The penetrating ability is 1.6 times that of air, it is difficult to dissolve in water, it does not support combustion and cannot maintain breathing. When it reaches a certain concentration, it can cause people to suffocate due to lack of oxygen, and can cause combustion or explosion. Therefore, mine ventilation is generally used in coal mines. And pumping gas, controlling gas gushing and other methods to prevent the gas concentration from exceeding the regulations to prevent accidents.

Since the coal mining face started mining, the movement of the overlying strata has been destroyed, causing the pressure relief of the gas in the adjacent layers, causing the generation and extension of the fracture zone, and providing conditions for the pressure relief, migration and continuous desorption of the gas in the adjacent layers.

In the initial mining stage of the coal mining face, with the first break of the old roof, a large amount of pressure-relieving gas from adjacent layers will flow into the working face, which will cause the working face gas to exceed the limit.

At present, domestic and foreign methods to control the gas gushing in the initial mining period include increasing the air volume to dilute the gas in the initial mining period, using drill holes to penetrate the high-level drainage roadway, adopting the U+I ventilation method, and using the pre-buried pipe on the return air side to extract gas from the goaf , Middle and low level back high drainage roadway for drainage of gas in the initial mining period, rear pseudo high drainage roadway for treatment of gas in the initial mining period, etc.

However, for the hard roof, the above control measures cannot achieve the desired effect. For example, the hard roof of the working face has a large collapse step. In the early stage of the initial mining stage of the working face, the roof does not collapse and the gas emission in the adjacent layers is small. , the ventilation method of U+I and the drainage technology of high-level drainage can not play an effective role; and after the collapse of the old top, due to the large collapse range, a large amount of gas gushed out, and the working face has been in the state of gas exceeding the limit for a period of time. It threatens the safety of underground personnel and affects normal production.

Contents of the invention

In view of the above-mentioned problems, the present invention provides a method for controlling the gas exceeding the limit in the initial mining stage of the hard roof fully mechanized caving face, which can effectively discharge the gas gushing out in the initial mining stage of the hard roof fully mechanized caving face, and prevent the occurrence of gas exceeding the limit , to provide a guarantee for the safe production of the fully mechanized caving face during the initial mining period.

In order to achieve the above purpose, this method of controlling the gas overrun in the initial mining stage of the hard roof fully mechanized caving face adopts the "U+I" type ventilation method, including arranging the inner staggered tail lane inside the return air lane, and Drain the gas in the coal seam by laying out along-bed boreholes in alleys and internal staggered alleyways, and arrange high-level drainage alleyways, rear pseudo-high-level drainage alleys, and low-level inclined high-level drainage alleys to extract gas from adjacent layers, and cooperate with the pre-splitting blasting technology of process lanes and Reasonable working face advancement speed comprehensively controls the problem of gas exceeding the limit in the initial mining stage of the hard roof fully mechanized caving face. The specific steps are as follows:

a. Arrange an inner staggered tail alley parallel to the return airway along the 15-25m of the inner staggered return airway on the roof of the coal seam,

b. Arrange bedding-based drilling in the air inlet lane, air return lane and internal staggered tail lane of the working face respectively. The drilling construction direction is perpendicular to the center line of the roadway. Determine the drilling angle according to the inclination angle of the coal seam, and the height of the opening position from the floor is less than 1m;

c. According to the geological conditions of the coal seam, determine the height of the fissure zone, and set the vertical distance H ₁ from the roof of the mining coal seam, and the horizontal distance L ₁ from the return air roadway to arrange the high-strike suction roadway;

d. Along the horizontal angle β with the return airway, the vertical return airway inclination angle α is excavated upwards and then the pseudo-high suction roadway is excavated, and it runs through the high-level suction roadway with the direction, and the excavation distance is about (H1/(sinα·cosβ));

e. Go up from the air return side along the already excavated false high extraction roadway to find the mudstone layer on the limestone roof, and excavate a low-level inclined high extraction roadway along the limestone roof along the horizontal direction with an angle of γ with the horizontal direction of the return air roadway. The internal length of the incision lane is L ₃ ;

f. Drill two rows of layer-crossing drill holes on the floor of the roadway with low slope and high extraction. The hole passes through the limestone 0.5 ~ 1.5m;

g. Arrange two process lanes from the inner staggered tail lane to the direction of the air inlet lane. The direction is parallel to the cutting lane. The length of the process lane is L ₂ . If the inclined length of the working face is L, the length of the process lane L ₂ is about (LL ₃ ) m ;

h. Arrange drilling charges in the process lane for pre-splitting blasting;

i． In the stage where the rear high-level drainage roadway, the low-level high-level drainage roadway and drilling play a role, and the stage when a large amount of gas in the adjacent layer is gushing out to the high-level drainage roadway to fully play its role, the advancing speed of the working face should be well controlled.

As a further improvement of the present invention, the inclination angle α is 35° to 40°, and the inclination angle β is 40° to 50°.

As a further improvement solution of the present invention, the said inclination angle β is 60-65°.

As a further improvement of the present invention, the distance _L3 of the low-level inclined high-pumping roadway extending into the cutting roadway is 40m, the vertical layer distance from the coal seam roof is about _H1 /2, and the cross-sectional area of the roadway is 2×2㎡ .

As a further improvement of the present invention, the positions of the two process lanes are set at 15m and 30m from the cutting lane in the inner staggered lane.

As a further improvement of the present invention, the advancing speed of the working face is less than 2m/day before the old roof collapses.

Compared with the existing technology, this method to control the gas exceeding the limit in the initial mining stage of the hard roof fully mechanized caving surface is a method of using process roadways and combined high-level pumping roadways to relieve pressure and drain the gas in the initial mining stage to prevent and control the hard roof fully mechanized caving surface. The method of gas exceeding the limit in the initial mining stage can be comprehensively designed to solve the problem of gas easily exceeding the limit in the initial mining stage of the fully-mechanized caving face because of the arrangement of the process roadway, the rear high drainage roadway, the low inclined high The blasting technology of the process roadway, the low-level inclined high-level pumping roadway and its layer-crossing drilling design can concentrate on solving the problem of the hard roof not collapsing during the initial mining period, and can shorten the caving step distance of the direct roof and the old roof, and then from the internal fault The gas in the adjacent layers of the tail roadway and the combined high-level drainage roadway is drained and released, which effectively avoids the poor drainage effect of the high-level drainage roadway during the initial mining period, and the gas influx into the working face of the adjacent layer causes the gas to exceed the limit. Safe production during the mining period provides a guarantee.

Description of drawings

Fig. 1 is a layout plan view of the present invention;

Fig. 2 is a layout plan view of the combined high pumping lane of the present invention;

Fig. 3 is a layout plan view of the process lane of the present invention;

Fig. 4 is the roadway layout I-I sectional schematic diagram of the present invention;

Fig. 5 is a schematic cross-sectional view of roadway layout II-II of the present invention.

In the figure: 1. Air inlet alley, 2. Air return alley, 3. Inner staggered tail alley, 4. Going to high extraction alley, 5. Rear false high extraction alley, 6. Low inclined high extraction alley, 7. Layer-penetrating drilling Hole, 8, craft alley, 9, cutting alley.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

This method to control the gas exceeding the limit at the initial stage of the fully mechanized caving face of the hard roof adopts the "U+I" type ventilation method, including arranging the inner staggered tail lane on the inner side of the return air lane, and In the roadway, drill holes along the bedding are arranged to extract the gas in the coal seam, and the direction high drainage roadway, the rear false high drainage roadway, and the low inclined high drainage roadway are arranged to drain the gas in the adjacent layer, and cooperate with the pre-splitting blasting technology of the process roadway and the reasonable working face advancement Speed comprehensive control of the problem of gas exceeding the limit in the initial mining stage of fully mechanized caving faces with hard roofs.

The specific steps of this method for controlling gas overrun in the initial mining stage of fully mechanized caving face are as follows:

a. Firstly, on the inner side of the return airway 2, an inner staggered tail alley 3 is arranged along the roof of the coal seam, and a 15-25m protective coal pillar is reserved between the return airway 2;

b. In the air inlet lane 1, return air lane 2 and inner cross-tail lane 3 of the working face, lay out bedding boreholes and gas drainage pipelines to extract the gas in the coal seam. The center line is vertical, opening from the coal side of the working face, the drilling distance of the road side is about 1m, the drilling length is designed according to the inclination length of the working face, the drilling angle is determined according to the coal seam inclination, and the opening position is less than 1m away from the bottom plate;

c. According to the geological conditions of the coal seam, the height of the fissure zone is determined, and the vertical distance H ₁ from the roof of the mining coal seam, and the horizontal distance L ₁ from the air return roadway 2 are arranged to strike the high suction roadway 4;

d. Along the horizontal angle β with the return airway 2, the vertical return airway 2 is excavated at an inclination angle α, and then the pseudo-high suction roadway 5 is excavated upwards, and it runs through the high-level suction roadway 4, and the excavation distance is about (H ₁ /(sinα·cosβ) );

e. Then go up from the air return side along the already excavated false high pumping roadway 5 to find the mudstone layer on the limestone roof, and excavate a low-level inclined high pumping road along the limestone roof along the horizontal direction with the horizontal angle of γ with the air return roadway 2. Lane 6, extending into the cutting lane 9, the internal length is L ₃ ;

f. Then drill two rows of layer-penetrating drill holes 7 on the roadway bottom plate of the low inclined high pumping roadway 6, 10 in each row. The distance is 0.3~0.8m, and the drill hole passes through the limestone 0.5~1.5m;

g. Excavate two craft lanes 8 parallel to the cutting lane 1 from the inner staggered tail lane to the air inlet lane 1. The direction is parallel to the cutting lane 9. The length of the craft lane 8 is L ₂ . If the inclined length of the working face is L, the craft lane 8 The length L ₂ is about (LL ₃ ) m;

h. Then arrange the drilling charges in the process lane 8 for pre-splitting blasting;

i． In the stage when the post pseudo-high drainage roadway 5, the low-level high-level drainage roadway 6 and drilling holes play a role, and the stage when a large amount of gas in the adjacent layer is gushing out to the high-level drainage roadway to play its full role, the advancing speed of the working face advance project in the initial mining period should be well controlled.

Since the high extraction roadway is arranged in the dense gas gushing area about 7-10 times the mining height, in order to solve the problem of gas gushing in the initial mining stage of the working face, the working face is arranged with a rear high drainage roadway, a rear high drainage roadway and a high Through, therefore, as a further improvement of the present invention, the said inclination angle α is 35-40°, and the said inclination angle β is 40-50°.

Due to the well-developed fissures in the middle of the goaf, the inclined arrangement of low-level and high-level pumping roads can penetrate deep into the middle of the rock formation, making it easier to release pressure and pump gas. Therefore, as a further improvement of the present invention, the slope angle β is 60 ~65°.

Since the low-level inclined high-level pumping roadway can go deep into the well-developed cracks in the rock formation, and the increase in the contact area between the roadway and the coal-rock layer makes it easier to release pressure and pump gas. Therefore, as a further improvement of the present invention, the low-level inclined The distance _L3 of the high pumping roadway (6) extending into the cutting roadway (9) is about 40m, the vertical layer distance from the coal seam roof is about _H1 /2, and the cross-sectional area of the roadway is 2×2㎡.

During the 40m recovery period of the initial mining period, the hard roof is not easy to collapse, and the old roof and periodic caving steps are relatively large, which affects the gas extraction effect of the high-level drainage roadway. The layout of the process roadway and pre-split blasting can shorten the old roof and the periodic caving step, the gas in the adjacent layer is released in advance, so that the rear high-level drainage roadway plays a role in draining the gas in the adjacent layer in advance, so as to reduce the amount of gas gushing from the adjacent layer to the working face during the initial mining period. Therefore, as In a further improvement solution of the present invention, the two process lanes are located at a distance of about 15m and 30m from the cutting lane in the inner staggered lane.

Since too fast advancement of the working face is one of the main factors causing the gas to exceed the limit in the initial mining period, before the old roof collapses, controlling the advancing speed of the working face can reduce the amount of gas gushing out per unit time. Therefore, as this In the further improvement scheme of the invention, the advancing speed of the working face is less than 2m/day before the old roof collapses.

Embodiment: Take the 15109 working face of Shanxi Shigang Coal Industry Co., Ltd. as an example to further illustrate the present invention.

According to the actual situation of the 15109 working face in Shigang Coal Mine, the coal mining face and production system are arranged, and the inclined length L of the working face is 140m.

Firstly, on the inner side of return airway 2 of 15109, an inner staggered tail alley 3 is arranged along the roof of the coal seam, and a 20m protective coal pillar is reserved between the return airway 2; The gas drainage boreholes of the tailway 3 are arranged in a row, and the drilling construction direction is perpendicular to the center line of the air inlet lane 1. The opening of the coal side of the working face is 1m apart, and the number of holes in the air inlet lane 1 is 1261. , the number of drilling holes in return airway 2 is 1224, and the number of drilling holes in inner cross-tail lane 3 is 468, with a diameter of 94mm. The engineering volume of each drilling hole is about 80m. The height of the hole is 1m from the bottom plate.

According to the geological conditions of the coal seam, the vertical distance from the roof of the mining coal seam is 40m, and the horizontal distance from the return airway 2 is 35m. Gaohua Lane 4 runs through.

Go up from the air return side along the already excavated false high extraction roadway 5, find the mudstone layer on the limestone roof, and excavate a low-level inclined high extraction roadway along the limestone roof along the horizontal direction with an angle of 60° to the horizontal direction of the air return roadway 6. Extend about 40m into the opening and cutting roadway 9, and the vertical layer distance from the roof of the coal seam is about 19m.

After digging the low inclined high drainage roadway, drill two rows of cross-layer drilling holes on the roadway floor of the low inclined high drainage roadway 6 to connect the gas drainage pipelines, with 10 holes in each row. 4m, the distance between the drill hole and the two sides of the roadway is 0.5m, and the drill hole passes through the limestone for about 1m.

In the inner cross-tail lane 3, about 15m and 30m away from the cutting lane 9, two process lanes 8 are excavated toward the air inlet lane 1 direction, the direction is parallel with the cutting lane 9, and the length of the craft lane 8 is 100m, then, Drilling charges are arranged in process lane 8 for pre-splitting blasting.

During the initial mining period, the advancing speed of the working face shall be well controlled, and the advancing speed shall not exceed 2m/day before the old roof collapses.

As the working face advances, the layout of process lanes, low-level inclined high-level drainage lanes, and layer-crossing drilling arrangements shorten the step distance of hard roof collapse, and the pressure-relieving gas of adjacent layers gushes out, passing through inner staggered tail lanes, rear high-level drainage lanes, and low-level inclined Drainage of high-level and high-level drainage lanes can effectively eliminate and control gas over-limit during the initial mining period of fully mechanized caving faces with hard roofs, and ensure safe production of the working face during the initial mining period.

This method of controlling the gas overrun in the initial mining stage of the hard roof fully mechanized caving face is a method of using the process roadway 8 and the combined high-pumping roadway 4 to relieve pressure and extract the gas in the initial mining stage to prevent and control the gas overrun in the initial mining stage of the hard roof fully mechanized caving face. The limited method can be used to comprehensively design and solve the problem of gas easily exceeding the limit in the initial mining period of fully mechanized caving faces; it can focus on solving the problem that the hard roof does not collapse during the initial mining period, and can shorten the caving step distance of the direct roof and the old roof, and then from the inside Staggered tail entry and combined high-drainage entry drain and release the adjacent layer gas, which effectively avoids the poor drainage effect of the high-drainage entry during the initial mining period. Safe production during the initial mining period provides a guarantee.

Claims (6)

1. administer the method for adopting phase gas exceeding limit at the beginning of tight roof comprehensive coal face for one kind, " U+I " type of employing draft type, it is characterized in that, be included in return airway (2) disposed inboard Nei Cuowei lane (3), and in air intake lane (1), this coal-bed gas of concordant hole pumping and mining is arranged in return airway (2) and Nei Cuowei lane (3), arrange strike high-bleeding roadway (4), rear pseudo-suction road (5), low level incline high-position alley pumping (6) extraction the next layer gas, and coordinate technique lane (8) Pre-splitting Blasting Technique and reasonably adopt phase gas exceeding limit problem at the beginning of face propulsion speed comprehensive regulation tight roof comprehensive coal face, concrete steps are as follows:

A. a Nei Cuowei lane (3) being parallel to return airway (2) is arranged along wrong return airway (2) 15 ~ 25m in roof;

B. respectively in work plane air intake lane (1), arrange concordant boring in return airway (2) and Nei Cuowei lane (3), drilling construction direction is vertical with center line in roadway, opening is helped by work plane coal, according to work plane tendency Design of length drillable length, according to seam inclination determination bore angle, position of opening is less than 1m from bottom plate heights;

C. according to coal geology situation, fissure zone height is determined, at distance working seam top board vertical distance H ₁, apart from return airway (2) horizontal range L ₁place arranges strike high-bleeding roadway (4);

D. edge and return airway (2) horizontal sextant angle β, vertical return airway (2) tilt angle alpha upwards excavates rear pseudo-suction road (5), and through with strike high-bleeding roadway (4), driving distance is about (H1/(sin α cos β));

E. along the rear pseudo-suction road (5) of having dug from return side up, find the layer position of limestone roof mud stone, the horizontal direction that edge and return airway (2) horizontal sextant angle are γ tunnels a low level incline high-position alley pumping (6) along limestone roof, and stretching into Kai Qie lane (9) inner length is L ₃;

F. make a call to two row's layer-through drillings (7) at the roadway floor of low level incline high-position alley pumping (6), the horizontal spacing of boring is 0.5 ~ 1.5m, and longitudinal pitch is 2 ~ 5m, and the distance of holing from roadway's sides is 0.3 ~ 0.8m, holes through limestone 0.5 ~ 1.5m;

G. arrange two technique lanes (8) from Nei Cuowei lane toward air intake lane (1) direction, direction is parallel with Kai Qie lane (9), and technique lane (8) length is L ₂, if work plane tendency length is L, then technique lane (8) length L ₂be about (L-L ₃) m;

H. in technique lane (8), arrange that borehole charge carries out presplit blasting;

I. play a role the stage at rear pseudo-suction road (5) and low level suction road (6) and boring, and the next layer gas pours out the stage that strike high-bleeding roadway plays one's part to the full, just adopt in phase advance of the face engineering and control face propulsion speed well.

2. adopt the method for phase gas exceeding limit at the beginning of improvement tight roof comprehensive coal face according to claim 1, it is characterized in that, described tilt angle alpha is 35 ~ 40 °, and described inclination angle beta is 40 ~ 50 °.

3. adopt the method for phase gas exceeding limit at the beginning of improvement tight roof comprehensive coal face according to claim 1 and 2, it is characterized in that, described inclination angle beta is 60 ~ 65 °.

4. adopt the method for phase gas exceeding limit at the beginning of improvement tight roof comprehensive coal face according to claim 1, it is characterized in that, described low level incline high-position alley pumping (6) stretches into the distance L in Kai Qie lane (9) ₃for 40m, with roof vertical inter-layer apart from being about H ₁/ 2, drift section is rectangle, and it is 2 × 2 ㎡ that drift section amasss.

5. adopt the method for phase gas exceeding limit at the beginning of improvement tight roof comprehensive coal face according to claim 1, it is characterized in that, two described technique lane (8) positions are arranged on Nei Cuowei lane (3) apart from cutting 15m, 30m place, lane.

6. adopt the method for phase gas exceeding limit at the beginning of improvement tight roof comprehensive coal face according to claim 1, it is characterized in that, described face propulsion speed was less than 2m/ days before main roof caving.