Fully coal pillar-free method for continuous mining of underground coal resources in terms of time and space

Abstract

The present invention relates to the field of coal mining, and particularly to a completely coal-pillar-free method for continuous mining of underground coal resources in terms of time and space. Considering the limitations in the recovery of protective coal pillars between existing underground mining working faces, on both sides of the upcast and main roadways, a method for continuous mining in terms of time and space within the underground mining scope is proposed. Within the mining area, there are no protective coal pillars between working faces, nor on both sides of the upcast and main roadways, realizing completely coal-pillar-free mining within the mining area. In this method, the return airway of the main return airway serves as the return airway of the first mining working face, and the main haulage roadway serves as the intake airway of the last mining working face. Between the working faces, two methods, namely the staggered floor and inner-offset method or the roof-cutting pressure-relief and automatic roadway formation method, are used for lapping. The mining area working face penetrates the track heading to form a gob-side entry, which also serves as the return airway and the equipment withdrawal passage. This method realizes that the main return airway and the main haulage roadway also serve as mining roadways, and the haulage heading is scrapped in sections, saving the amount of roadway engineering work; there are completely no coal pillars within the mining area, improving the existing working mode of coal pillar recovery.

Description

Technical Field

[0001] The present invention relates to the field of coal mining, and particularly to a completely pillarless method for continuous mining of underground coal resources in terms of time and space. Background Art

[0002] At present, the mine fields in China are basically in a sectional or strip form. When arranging working faces in a mining area or a strip area, at least 20 - 40 m of protective coal pillars need to be reserved between the upcast shafts and on both sides of the main roadways. If the common downward mining method in a mining area or the retreating mining method in a strip area is adopted, it is difficult to completely recover the protective coal pillars between the upcast shafts and on both sides of the main roadways, resulting in a certain amount of coal loss. Even if the upward mining method in a mining area or the advancing mining method in a strip area is adopted, the protective coal pillars between the upcast shafts or on both sides of the main roadways can be recovered only after the last working face has been mined, but this method is not universal.

[0003] At the same time, the conventional working face roadways in a mining area or a strip area are all arranged at the same horizon. Generally, about 20 m of sectional coal pillars need to be reserved between the working faces. These roadway - protecting coal pillars are regarded as permanently lost coal pillars, causing a large amount of coal resource loss in the mining area.

[0004] In summary, in underground mining, coal loss includes the coal pillars for protecting roadways in the working face, on both sides of the upcast shafts or main roadways, and between the upcast shafts or main roadways. However, the problems in underground mining are not limited to the recovery rate. When the working face advances towards the upcast shaft or the main roadway, a retreat - channel needs to be arranged at the outer end of the protective coal pillar on the side of the upcast shaft or the main roadway close to the working face. Common methods include enlarging the rib, single - retreat channel and double - retreat channel. Among them, the double - retreat channel is the most advanced, that is, two roadways parallel to the working face are dug along the outer end of the protective coal pillar. The distance between the two roadways is generally about 20 m, and a connecting roadway is arranged every 30 - 50 m between the two roadways. After the working face advances to the outer retreat channel, the equipment is withdrawn, and multi - point withdrawal is carried out by using the two retreat channels and their connecting roadways. Generally speaking, the withdrawal of mining equipment takes a long time, and the retreat channel needs to be deployed in advance, increasing the roadway engineering volume.

[0005] To sum up, in shaft - mine mining, there are protective coal pillars for the main roadway or upcast shaft and sectional coal pillars in the working face. When the working face advances to the outer end of the protective coal pillar, a retreat channel needs to be arranged, increasing the shaft - roadway engineering volume and prolonging the moving - time. More importantly, the remaining coal pillars, as stress carriers, affect the surrounding shaft - roadway engineering, especially forming high stress in the adjacent coal seams. In this case, dynamic disaster problems represented by rock bursts are extremely likely to occur. Therefore, based on solving the above problems, this invention patent uses the surrounding shaft - roadways as the mining roadways and retreat channels during the working - face mining, without leaving coal pillars on the side and the advancing direction of the working face, realizing pillarless penetration. Summary of the Invention

[0006] In view of the above technical problems, the object of the present invention is to propose a completely pillarless method for continuous mining of underground coal resources in terms of time and space, so as to solve the technical limitations existing in the prior art.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The completely pillarless method for continuous mining of underground coal resources in terms of time and space includes the following processes:

[0009] a. According to the common mining mode of well field division, use the main haulage roadway and the return airway to circle out the stages within the well field. Within the stage, use two or three upcast shafts to circle out the panel area. Use the return airway as the return airway of the first mining face. On the other side, drive a haulage roadway along the coal seam roof, which also serves as the intake airway. Connect the haulage roadway and the return airway to form a cutting roadway and prepare for mining.

[0010] b. As the working face advances forward for coal mining, a gob area is formed behind the working face. At this time, the return airway section on the gob side can be treated according to the air shaft. If the air shaft is located in front of the advancing direction of the working face, then the gob section of the return airway can be directly abandoned. Otherwise, the gob-side entry retaining technology needs to be adopted to retain the return airway for continuous air return service for this panel.

[0011] c. When the working face advances to the last coal mining area, that is, when entering the end mining stage, starting from the influence of the advanced abutment pressure on the nearest upcast shaft, adopt the technology of adjusting the advancing speed of the working face, controlling the mining height and strengthening the end mining of the upcast shaft roadway to avoid damage to the upcast shaft roadway.

[0012] d. When the working face is in end mining, no upcast shaft protection coal pillar is left and no special extraction roadway is set up. It is directly connected to the proximal upcast shaft. At the same time, extend the haulage roadway of the working face to the distal upcast shaft and finally connect them.

[0013] e. After connection, on the return airway side of the working face, use the upper panel station and the extended haulage roadway at the lower end to continue advancing towards another upcast shaft. Seal the abandoned return airway side with a sealed wall, and also seal the passed-upcast shaft with a sealed wall to block the air flow from flowing along the upcast shaft to the gob side.

[0014] f. The working face is directly connected to another upcast shaft. After connection, stop mining. The equipment in the upcast shaft can be directly used for relocation. According to whether the upcast shaft continues to be used as the ventilation route, choose to directly abandon it or retain the gob-side entry.

[0015] g. The return airway of the second working face is arranged along the haulage roadway mined under the roof goaf of the first mining face. The layout method of the haulage roadway of the second working face is the same as that of the first mining face. After the two roadways are connected, start mining. Its process is the same as steps c and d above. The upper panel station in step e is adjusted to the second section panel station accordingly.

[0016] h. For the remaining working faces in the middle of the mining area, repeat step g until the last working face. The return airway is the same as in step g. The main haulage roadway is directly used as the intake and haulage roadways for the last mining face. After the working face has been pushed through, roof cutting and pressure relief roadway formation can be used to retain and continue to serve, or gob-side entry retaining of the main haulage roadway can be achieved by building walls during mining.

[0017] According to the method of the present invention, preferably, it is a completely pillarless method applicable to continuous mining of underground coal resources in terms of time and space.

[0018] Specifically, in step a, according to the general mining mode of well field division, the stages within the well field are circled using the main haulage roadway and the return airway. Within the stage, the mining area range is circled using two or three upcast shafts. The return airway of the first mining face is the return airway. On the other side, a haulage roadway is driven along the coal seam roof, which also serves as the intake airway. The haulage roadway and the return airway are connected to form a cut-through opening for preparation for mining.

[0019] In step b, as the working face advances for coal mining, a gob area is formed behind the working face. At this time, the return airway section on the gob side can be treated according to the air shaft. If the air shaft is located in front of the working face advance, then the gob section of the return airway can be directly abandoned. Otherwise, gob-side entry retaining technology needs to be used to retain the return airway for continuous air return service for this mining area.

[0020] In step c, when the working face advances to the last coal mining area, that is, when entering the last mining stage, starting from the influence of the advanced abutment pressure on the nearest upcast shaft, measures such as adjusting the working face advance speed, controlling the mining height, and strengthening the last mining technology of the upcast shaft are taken to avoid damage to the upcast shaft roadway.

[0021] In step d, no upcast shaft protection coal pillar is left in the last mining of the working face, and no special withdrawal roadway is set up. It is directly connected to the nearest upcast shaft. At the same time, the haulage roadway of the working face is extended towards the far-end upcast shaft until it is finally connected.

[0022] In step e, after connection, on the return airway side of the working face, continue to advance towards another upcast shaft using the upper yard of the mining area and the extended haulage roadway at the lower end. A sealed wall is built on the side of the abandoned return airway, and a sealed wall is also built on the pushed-through upcast shaft to block the air flow from flowing along the upcast shaft to the gob side.

[0023] In step f, the working face is directly connected to another upcast shaft. After connection, stop mining. The equipment in the upcast shaft can be directly used for relocation. According to whether the upcast shaft continues to be used as a ventilation route, direct abandonment or gob-side entry retaining can be selected.

[0024] In step g, the return airway of the second working face is arranged along the roof of the first mining face under the goaf of the belt conveyor gateway. The arrangement of the belt conveyor gateway of the second working face is the same as that of the first mining face. After the two gateways are connected, mining is carried out, and the process is the same as steps c and d described above. The upper yard in step e is adjusted to the second section yard accordingly.

[0025] In step h, the rest of the working faces in the middle of the mining area are repeated according to step g until the last working face. The return airway is the same as that in step g. The main haulage roadway is directly used as the intake airway and belt conveyor gateway of the last mining face. After the working face has advanced, roof cutting and pressure relief roadway formation can be adopted to retain and continue to serve, or gob-side entry retaining of the main haulage roadway can be achieved by building walls during mining.

[0026] Compared with the prior art, the completely pillarless method for continuous mining of underground coal resources in terms of time and space provided by the present invention has the following advantages:

[0027] (1) The return airway and the main haulage roadway also serve as mining gateways, saving the amount of roadway engineering; the haulage rise is taken over by the working face and scrapped in sections, reducing the roadway maintenance cost; the track rise is gob-side entry retained or scrapped in sections, which can continue to serve the other sections or reduce the maintenance cost and improve the roadway utilization rate.

[0028] (2) Continuous mining within the underground mining area is realized. Within the mining area, there are no protective coal pillars on both sides of the main haulage roadway, no protective coal pillars between rises, and no protective coal pillars between working faces, completely achieving complete pillarless within the mining area.

[0029] (3) The abutment pressure of the return airway of the subsequent working face is low. In the method of the present invention, the overlying strata are caved gangue in the goaf, realizing the integration of continuous mining between working faces and overlying strata movement. The roadway load is small, avoiding the prominent phenomenon of abutment pressure concentration in adjacent roadways of the subsequent working face; at the same time, it improves the influence of long-term high stress commonly existing in the rises or main haulage roadways of underground mining in China. The pillarless connection completely liberates the roadway engineering of the coal seam and adjacent coal seams. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic layout diagram of the double-return roadway for the last mining face and the working face for recovering the coal pillar of the rise in the existing mining area.

[0031] Figure 2 It is a schematic diagram of the completely pillarless mining technology for continuous mining of underground coal resources in terms of time and space in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] The specific embodiments of the present invention will be described in conjunction with the accompanying drawings.

[0033] In this embodiment, in the first step, according to the common mining mode of well - field division, the stages within the well - field are circled out by using the main haulage roadway and the return airway. Within the stage, the panel area is circled out by using two or three upcast headings. The return airway is used as the return airway of the first mining face. On the other side, a haulage roadway is driven along the coal seam roof, which also serves as the intake airway. The haulage roadway and the return airway are connected to form a cutting - eye to prepare for mining.

[0034] In the second step, as the working face advances forward for coal mining, a goaf is formed behind the working face. At this time, the section of the return airway on the goaf side can be processed according to the position of the air shaft. If the air shaft is located in front of the advancing working face, then the goaf section of the return airway can be directly abandoned. On the contrary, the gob - side entry - retaining technology needs to be adopted to retain the return airway to continue serving the return air of this panel area.

[0035] In the third step, when the working face advances to the last coal - mining area, that is, when entering the end - mining stage, starting from the influence of the advanced abutment stress on the nearest upcast heading, adopt the technology of adjusting the working - face advancing speed, controlling the mining height and strengthening the end - mining of the upcast heading to avoid damaging the upcast heading.

[0036] In the fourth step, no upcast - heading protective coal pillar is left in the end - mining of the working face, and no special extraction roadway is set up. The working face is directly connected to the proximal upcast heading. At the same time, the haulage roadway of the working face is extended towards the distal upcast heading and finally connected.

[0037] In the fifth step, after connection, on the return - airway side of the working face, continue to advance towards another upcast heading by using the upper panel station and the extended haulage roadway at the lower end. A sealed wall is built on the abandoned return - airway side, and a sealed wall is also built on the passed - through upcast heading to block the air flow flowing along the upcast heading towards the goaf side.

[0038] In the sixth step, the working face is directly connected to another upcast heading. After connection, the mining stops. The equipment in the upcast heading can be directly used for relocation. According to whether the upcast heading continues to be used as the ventilation route, it can be directly abandoned or the gob - side entry - retaining technology can be adopted.

[0039] In the seventh step, the return airway of the second working face is arranged along the roof - haulage roadway of the first mining face under the goaf. The layout method of the haulage roadway of the second working face is the same as that of the first mining face. After the two roadways are connected, mining is carried out. The process is the same as that of the third and fourth steps above. The upper panel station in the fifth step is adjusted to the second - section panel station accordingly.

[0040] In the eighth step, the remaining working faces in the middle of the panel area all repeat the seventh step until the last working face. The return airway is the same as in the seventh step. The main haulage roadway is directly used as the intake and haulage roadways of the end - mining working face. After the working face has passed through, the gob - side entry - retaining technology of roof - cutting and pressure - relief roadway formation can be adopted to retain it for continued service, or the gob - side entry - retaining of the main haulage roadway can be realized by building walls during mining.

Claims

1. A completely pillarless method for continuous mining of underground coal resources in terms of time and space, characterized in that, it includes the following processes: a. According to the general mining mode divided by the mine field, use the main haulage roadway and the return airway to enclose the stages within the mine field. Within the stage, use two or three upcast shafts to enclose the mining area. Use the return airway as the return airway of the first mining face. On the other side, drive the haulage roadway along the coal seam roof, which also serves as the intake airway. Connect the haulage roadway and the return airway to form the cutting roadway to prepare for mining; b. As the working face advances for coal mining, a goaf is formed behind the working face. At this time, the return airway section on the goaf side can be processed according to the position of the air shaft. If the air shaft is located in front of the advancing working face, then the goaf section of the return airway can be directly abandoned. Otherwise, the gob-side entry retaining technology needs to be adopted to retain the return airway for continuous ventilation service of this mining area; c. When the working face advances to the last coal mining area, that is, when entering the end mining stage, starting from the influence of the advanced abutment pressure on the nearest upcast shaft, adopt the technology of adjusting the working face advancing speed, controlling the mining height and strengthening the end mining of the upcast shaft roadway to avoid damage to the upcast shaft roadway; d. Do not leave a coal pillar for protecting the upcast shaft at the end mining of the working face, do not set a dedicated withdrawal roadway, and directly connect with the nearest upcast shaft. At the same time, extend the haulage roadway of the working face to the far-upcast shaft and finally connect through; e. After connection, on the side of the return airway of the working face, continue to advance towards another upcast shaft by using the upper yard of the mining area and the extended haulage roadway at the lower end. Build a sealed wall on the side of the abandoned return airway and also build a sealed wall on the passed-upcast shaft to block the air flow from flowing along the upcast shaft to the goaf side; f. The working face is directly connected with another upcast shaft. After connection, stop mining. The equipment in the upcast shaft can be directly used for moving. According to whether the upcast shaft continues to be used as the ventilation route, choose to directly abandon it or retain the gob-side entry; g. The return airway of the second working face is arranged along the haulage roadway mined under the roof goaf of the first mining face. The arrangement method of the haulage roadway of the second working face is the same as that of the first mining face. After connecting the two roadways, carry out mining. Its process is the same as steps c and d above. The upper yard in step e is adjusted to the second section yard accordingly; h. The remaining working faces in the middle of the mining area all repeat step g until the last working face. The return airway is the same as in step g. Use the main haulage roadway directly as the intake and haulage roadways of the end mining working face. After the working face has passed, the gob-side entry retaining by roof cutting and pressure relief can be adopted to retain it for continuous service, or the gob-side entry retaining of the main haulage roadway can be realized by building walls during mining.

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