Comprehensive pressure relief and scour prevention mining method for working face roadway and stope of extra-thick coal seam
By arranging section coal pillars and pressure relief roadways between the working faces of extra-thick coal seams, pressure relief layers and reserved layers are formed. By utilizing thin coal seam mining technology, the problem of large-scale damage caused by mining overburden in extra-thick coal seams is solved, and safe and efficient mining results are achieved.
Patent Information
- Application Number
- CN202511705956.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2025-12-30
AI Technical Summary
The mining of extra-thick coal seams can cause extensive damage to the overlying rock, leading to large-scale collapse of the coal face, coal wall spalling, and roadway exposure. It can even cause rock movement disasters such as rock bursts, threatening the safe and efficient production of the mine.
Sectional coal pillars are arranged between extra-thick coal seam working faces, and pressure relief roadways are constructed on top of them to form pressure relief layers and reserved layers. The pressure relief layers are mined using thin coal seam mining technology, and the reserved layers are used to support the overlying roof, reducing the impact of overlying rock fractures on the working face, mining area, and roadways.
By mining the pressure relief layer and supporting the reserved layer, the difference in the downward displacement distance between the basic roof and the overlying strata was reduced, the impact of the overlying strata on the working face, mining area and roadway was reduced, comprehensive pressure relief and anti-scour mining was achieved, and the disturbance of the coal mining roadway was reduced.
Smart Images
Figure CN121229092A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rockburst prevention in coal mining, and particularly to a comprehensive stress relief and rockburst prevention method for working faces and mining areas in extra-thick coal seams. Background Technology
[0002] Extra-thick coal seams generally refer to coal seams with a thickness greater than 8 meters. Extra-thick coal seam working faces are characterized by large mining areas, severe impacts from overburden mining, and large spaces for overburden strata movement, deformation, and fracture, resulting in a larger area of overburden mining damage compared to thin and medium-thick coal seams. Statistical analysis of 46 extra-thick coal seam mines showed that the ratio of the fracture zone height to the mining height was a maximum of 29.6, a minimum of 8.6, and an average of 18.1. The large-scale destruction of overburden spaces and the extensive energy transfer during mining in extra-thick coal seams easily lead to phenomena such as large-area pressure on the mining face, coal wall spalling, and strong mine pressure manifestations in roadways and coal pillars. In severe cases, it can even cause rock movement disasters such as rock bursts. Especially with the high-intensity mining of extra-thick coal seams and the increase in underground goaf areas, the extremely large spaces and strong disturbances can even cause mutual influence, mutual induction, and mutual reinforcement among various disasters, resulting in a chain of compound disasters that seriously threaten the safe and efficient production of extra-thick coal seam mines. Therefore, how to safely mine extra-thick coal seams and solve the problem of rockburst in the working face and roadway of extra-thick coal seams has become a technical challenge in this field. Summary of the Invention
[0003] To address the problem of rockburst in mining areas and roadways of extra-thick coal seams, this invention proposes a comprehensive pressure relief and rockburst prevention method for working faces and roadways in extra-thick coal seams, comprising the following steps:
[0004] Step 1: Arrange a section coal pillar between two adjacent working faces, and arrange a coal mining roadway on the side of the two adjacent working faces closest to the section coal pillar;
[0005] Step 2: Construct a small-section pressure relief roadway along the working face advance direction at the top coal boundary of the auxiliary roadway above the transition hydraulic support; design the coal seam between the left and right pressure relief roads as the pressure relief layer, and the coal seam between the pressure relief layer and the immediate roof as a reserved layer.
[0006] Step 3: Use thin coal seam mining technology to mine the pressure relief layer, and reserve the space formed after the pressure relief layer collapses and breaks into the mining area, as well as the original space of the reserved layer.
[0007] Step 4: First, carry out top coal caving mining on the left working face. Under the action of mine pressure, the caving layer is broken into coal blocks and released from the top coal caving hydraulic support. At the same time, some of the reserved layers collapse and the broken coal blocks formed will also be released with the coal flow. Carry out coal mining and coal release work on the right working face in the same way.
[0008] As a further optimization of the above scheme, in the first step, the top coal above the coal roadway is not mined as the top coal of the main protection roadway; the area mined by the top coal caving hydraulic support is defined as the main mining layer, and the mining area under the transition hydraulic support is defined as the auxiliary mining layer. The top coal above the main mining layer is released using the coal caving process, and this part of the top coal is defined as the caving coal layer. The top coal above the transition hydraulic support is not caved and is retained as the top coal of the auxiliary protection roadway. In the area of the caving coal layer near the top coal of the auxiliary protection roadway, some triangular top coal cannot be released.
[0009] As a further optimization of the above scheme, in the second step, the height and width of the pressure relief channel are both 2m; the height of the pressure relief layer is 1.5m, and the thickness of the reserved layer is 2m.
[0010] As a further optimization of the above scheme, in the second step, a pressure relief roadway is constructed at the junction of the top coal and the triangular top coal in the upper auxiliary roadway of the transition hydraulic support.
[0011] As a further optimization of the above scheme, in the fourth step, as a parallel technical solution, coal mining and coal release work is carried out first on the right working face, and then coal mining and coal release work is carried out on the left working face.
[0012] Invention Points and Beneficial Effects: Addressing the problem of rockburst in mining areas and roadways of extra-thick coal seams, this invention proposes first mining a thin pressure relief layer in the top coal (section pillar + roadway protection top coal + triangular pillar) where no release mining is carried out. A reserve layer is then set between the pressure relief layer and the immediate roof, utilizing the expansion and fracture of the reserve layer to continue supporting the overlying roof strata after the pressure relief layer is mined. When the extra-thick coal seam working face is mined, the downward displacement distance of the basic roof and its overlying strata in the working face mining area (forming a goaf after mining) is... The difference in the downward displacement distance between the basic roof and the overlying strata above the coal pillar in the section decreases, thereby reducing the impact of the collapse of the basic roof and the overlying strata on the working face, mining area, and roadway. Furthermore, the coal blocks formed by the breakage of the reserved layer after the depressurization layer is mined form a soft cushion layer, which can buffer and absorb the collapse of the direct roof and the overlying strata (including the basic roof) above it, further reducing the impact of overlying strata fracturing on the coal mining roadway, thus realizing the comprehensive depressurization and anti-shocking mining of the working face, roadway, and mining area of extra-thick coal seams. Attached Figure Description
[0013] When considered in conjunction with the accompanying drawings, the invention will be more fully and better understood, and many of its accompanying beneficial effects will become readily apparent, by referring to the following detailed description. However, the accompanying drawings, which are provided to further illustrate the invention and form part of this invention, and the illustrative embodiments thereof, together with their descriptions, are used to explain the invention and do not constitute an undue limitation thereof, wherein:
[0014] Figure 1 —A schematic cross-sectional view of the arrangement of adjacent working faces in the extra-thick coal seam according to the present invention;
[0015] Figure 2 —Schematic diagram of the arrangement of the pressure relief layer in the extra-thick coal seam working face of this invention;
[0016] Figure 3 —A schematic diagram of the decompression layer of the extra-thick coal seam working face after mining according to the present invention;
[0017] Figure 4 —A schematic diagram of the top coal flow in the unloading layer after mining of the extra-thick coal seam working face according to the present invention;
[0018] Figure 5 —A schematic diagram of roof collapse after mining of the extra-thick coal seam working face according to the present invention;
[0019] Attached image description: Figure 1-5 The left and right working faces are only partially shown; 1-Main mining layer; 2-Releasing layer; 3-Auxiliary mining layer; 4-Top coal of auxiliary roadway; 5-Mining roadway; 6-Top coal of main roadway; 7-Sectional coal pillar; 8-Reserved layer; 9-Triangular top coal; 10-Issued roof; 11-Basic roof; 12-Pressure relief roadway; 13-Pressure relief layer; 14-Reserved layer in collapse state; 15-Releasing layer in fractured state; 16-Remaining unreleased coal of collapsed immediate roof and releasing layer; 17-Issued immediate roof in collapse state; 18-Basic roof in fractured state. Detailed Implementation
[0020] To better understand the technical content of this invention, specific embodiments are described below in conjunction with the accompanying drawings. Various aspects of this invention are described with reference to the accompanying drawings, which illustrate numerous illustrative embodiments. The embodiments of this invention are not limited to those shown in the drawings. It should be understood that this invention is implemented through any of the various concepts and embodiments described above, as well as the concepts and embodiments described in detail below, because the concepts and embodiments disclosed in this invention are not limited to any particular implementation. Furthermore, some aspects of this invention can be used alone or in any suitable combination with other aspects disclosed in this invention.
[0021] like Figure 1-5 As shown, taking the Shadunzi Coal Mine as an example, this invention introduces the method for preventing rockbursts by artificial fracturing in key near and far-field layers of extra-thick coal seams. The main coal seam mined in the Shadunzi Coal Mine is the No. 4 extra-thick coal seam, with an average thickness of about 13m. It is mined using the top coal caving mining process, with a mining height of 5m. The remaining 8m is released using the caving mining process. The specific mining method includes the following steps:
[0022] Step 1: As Figure 1As shown, a section coal pillar 7 is arranged between two adjacent working faces, with a width of 25m. The left side of the section coal pillar 7 is the left working face, and the right side is the right working face. A mining roadway 5 is arranged on the side of the two adjacent working faces closest to the section coal pillar 7, with a width and height of 5m. The top coal above the mining roadway 5 is not mined; the main protection roadway top coal 6 is used to protect the mining roadway 5. The two adjacent working faces are designed to use top coal caving mining technology, with a designed mining height of 5m. The area mined by the top coal caving hydraulic support is defined as... The main mining layer 1 is defined as the mining area under the support of the transition hydraulic support, which is defined as the auxiliary mining layer 3. The top coal above the main mining layer 1 is released using the coal release process, and this part of the top coal is defined as the release coal layer 2. The top coal above the transition hydraulic support, which is also the top coal above the auxiliary mining layer 3, is not released and is retained as the top coal 4 of the auxiliary roadway to protect the mining roadway 5. Based on the characteristics of strata collapse, it is known that in the area of the release coal layer 2 near the top coal 4 of the auxiliary roadway, there will be some triangular top coal 9 that cannot be released, that is, this part of the triangular top coal 9 is not separated from the top coal 4 of the auxiliary roadway.
[0023] Step 2: As Figure 2 As shown, a pressure relief roadway 12 with a height and width of 2m is constructed along the working face advancement direction at the junction of the top coal 4 and the triangular top coal 9 in the auxiliary roadways on the left and right sides. The bottom plate of the auxiliary roadway 12 is 9.5m away from the bottom plate of the coal seam. The coal seam with a thickness of 1.5m between the left and right auxiliary roadways 12 is designed as a pressure relief layer 13. The bottom layer of the pressure relief layer 13 is consistent with the bottom layer of the auxiliary roadway 12. The coal seam between the pressure relief layer 13 and the immediate roof 10 is used as a reserved layer 8 with a thickness of 2m. The bottom surface of the pressure relief layer 13 is 4.5m away from the top plate of the mining roadway.
[0024] Step 3: As Figure 3 As shown, based on the auxiliary roadway 12, a thin coal seam mining process, such as spiral drilling, is used to mine the pressure relief layer 13. The coal after the pressure relief layer 13 is mined is transported out of the pressure relief roadway 12. After the pressure relief layer 13 is mined, the reserved layer 8 above the pressure relief layer 13 collapses and breaks into the space formed after the pressure relief layer 13 is mined and the original space of the reserved layer. The reserved layer 14 after the collapse has the characteristic of fragmentation and expansion, which can support the immediate roof 10. At the same time, since the pressure relief layer 13 and the coal mining roadway 5 maintain a sufficient distance, the disturbance to the coal mining roadway 5 can be limited to a controllable range.
[0025] Step 4: As Figure 4-5 As shown, the left working face is first mined by top coal caving, mining the main mining layer 1 and the auxiliary mining layer 3. The caving layer 2 is broken into coal blocks 15 under the action of mine pressure and released from the top coal caving hydraulic support. At the same time, some of the reserved layers collapse and the broken coal blocks formed are also released with the coal flow. The right working face is mined and released in the same way.
[0026] After the extra-thick coal seam is mined, most of the coal in the vented seam 2 is released, with some remaining in the goaf, where it merges with the collapsed immediate roof. Figure 5 The basic roof 18 and its overlying strata (located at points 16 and 17) supported the collapse of the upper part. Due to the mining of the pressure relief layer 13, the difference between the downward displacement distance of the basic roof 18 and its overlying strata in the working face mining area (forming a goaf after mining) and the downward displacement distance of the basic roof 11 above the section coal pillar 7 (the downward displacement distance of the basic roof 11 and the immediate roof 10 is basically the same) and its overlying strata is reduced (at least 1.5m). This reduces the impact of the collapse of the basic roof and its overlying strata on the working face mining area and roadway. Furthermore, the coal blocks formed by the broken reserved layer after the mining of the pressure relief layer 13 form a soft cushion layer, which can buffer and absorb the collapse of the immediate roof and the overlying strata above it, further reducing the impact of the overlying strata fracture on the coal mining roadway, thereby achieving comprehensive pressure relief and anti-shocking mining of the extra-thick coal seam working face roadway and mining area.
[0027] Of course, the above description is only a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. It should be noted that any equivalent substitutions or obvious modifications made by those skilled in the art under the guidance of this specification fall within the scope of this specification and should be protected by the present invention.
Claims
1. A method for comprehensive pressure relief and rock burst prevention mining of a roadway and a mining face of an extra-thick coal seam, characterized in that, The method comprises the following steps: First step: arranging a section coal pillar between two adjacent working faces, and arranging a coal mining crossheading on the side close to the section coal pillar of the two adjacent working faces; Second step: constructing a small crossheading pressure relief crossheading along the working face advancing direction on the upper auxiliary support of the transition hydraulic support; designing the coal seam between the left and right pressure relief crossheadings as a pressure relief layer, and designing the coal seam between the pressure relief layer and the immediate roof as a reserved layer; Third step: mining the pressure relief layer by using a thin seam mining process, and mining the reserved layer and the space formed after the reserved layer collapses and breaks into the space after the pressure relief layer is mined and the original space of the reserved layer; Fourth step: first, carrying out top coal caving mining on the left working face, and under the action of the mine pressure, the caving layer is broken into coal blocks and is caved from the top coal caving hydraulic support, and part of the broken coal blocks formed by the collapse of the reserved layer are also caved with the coal flow; and in the same way, the right working face is subjected to the coal mining and caving work.
2. The method according to claim 1, wherein, In the first step, the top coal above the coal mining crossheading is not mined as the main support of the roof coal; the area mined by the top coal caving hydraulic support is defined as the main mining layer, and the mining area supported by the transition hydraulic support is defined as the auxiliary mining layer, wherein the top coal above the main mining layer is caved by using the caving process, and this part of the top coal is defined as the caving layer, and the top coal above the transition hydraulic support is not mined and is reserved as the auxiliary support of the roof coal; the caving layer will have part of the triangular top coal that cannot be caved in the area close to the auxiliary support of the roof coal.
3. The method according to claim 2, wherein, In the second step, the height and width of the pressure relief crossheading are both 2m; the height of the pressure relief layer is 1.5m, and the thickness of the reserved layer is 2m.
4. The method according to claim 2, wherein, In the second step, the pressure relief crossheading is constructed at the junction of the auxiliary support of the roof coal and the triangular top coal above the transition hydraulic support.
5. The method according to claim 1, wherein, In the fourth step, as a parallel technical solution, the right working face is subjected to the coal mining and caving work first, and then the left working face is subjected to the coal mining and caving work.