CN114060032B - Mining method for reserving protective coal pillar on steep-dip extra-thick coal seam - Google Patents
Mining method for reserving protective coal pillar on steep-dip extra-thick coal seam Download PDFInfo
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- CN114060032B CN114060032B CN202111314958.4A CN202111314958A CN114060032B CN 114060032 B CN114060032 B CN 114060032B CN 202111314958 A CN202111314958 A CN 202111314958A CN 114060032 B CN114060032 B CN 114060032B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/003—Machines for drilling anchor holes and setting anchor bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/028—Devices or accesories for injecting a grouting liquid in a bore-hole
Abstract
The invention provides a mining method for reserving protective coal pillars in a steep super-thick coal seam, which comprises the following steps: the method comprises the following steps of S1, determining the position of a first mining working face based on coal seam occurrence characteristics, and dividing the coal seam into a plurality of horizontal sections according to the first mining working face; s2, arranging two mining working faces in each horizontal section, reserving coal pillars between the two mining working faces of the same horizontal section, and supporting the top plate and the bottom plate of the mining working faces through the coal pillars; s3, adopting a backward mining sequence to simultaneously mine two mining working faces of the same horizontal section, and grouting and reinforcing reserved coal pillars corresponding to the top plate of the next horizontal section when the mining working faces are pushed for a certain distance; and S4, repeating the steps S2-S3, and mining the plurality of horizontal subsections in sequence. The method can effectively control the movement of the coal seam roof rock stratum, and has important significance in reducing surface subsidence and protecting the ecological environment while safely and efficiently mining resources.
Description
Technical Field
The invention belongs to the technical field of surface subsidence control in mining of a steep-dip extra-thick coal seam, and particularly relates to a mining method for reserving protective coal pillars in the steep-dip extra-thick coal seam.
Background
A large amount of steeply inclined extra-thick coal seams are reserved in western large coal production bases in China. In the face of a steep-dip extra-thick coal seam, the horizontal sublevel caving coal mining method is widely used as an economic and efficient mining means suitable for the steep-dip extra-thick coal seam. The method raises the exploitation efficiency and brings a plurality of environmental problems. The original horizontal sublevel caving coal mining method can cause repeated disturbance influence on the roof plate, so that a large collapse pit is formed on the ground surface, and the range of the collapse pit on the ground surface can be gradually enlarged along with the forward propulsion of a stope face. And after the mine enters deep mining, the waste rock in the goaf and the working face top plate form a hinged structure, so that a large-area suspended roof is formed on the side of the top plate, and potential threats are caused to the safe stoping of the working face.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a mining method for effectively solving the problem of surface collapse caused by roof collapse.
In order to achieve the above purpose, the invention provides the following technical scheme:
a mining method for reserving protective coal pillars on a steep and ultra-thick coal seam comprises the following steps:
the method comprises the following steps that S1, the position of a first mining working face is determined based on coal seam occurrence characteristics, the first mining working face horizontally extends along the trend of the coal seam, and the coal seam is divided into a plurality of horizontal sections according to the first mining working face;
step S2, arranging two mining working faces in each horizontal section, tunneling a roadway for each mining working face, reserving coal pillars between the two mining working faces of the same horizontal section during tunneling, supporting a top plate and a bottom plate of the mining working faces through the coal pillars, and anchoring and protecting the coal pillars;
s3, adopting a backward mining sequence to simultaneously mine two mining working faces of the same horizontal section, and grouting and reinforcing reserved coal pillars corresponding to the top plate of the next horizontal section when the mining working faces are pushed for a certain distance;
and S4, repeating the steps S2-S3, and mining the plurality of horizontal subsections in sequence.
In the mining method for reserving protective pillars in the steeply inclined and extremely thick coal seam, preferably, in step S3, the contact surfaces between the top plate and the bottom plate of the horizontal section to be mined and the corresponding pillars are reinforced.
In the mining method for reserving the protective coal pillar in the steeply inclined extra-thick coal seam, preferably, the coal pillar extends along the center line of the mining working face, and includes a horizontal portion and a support portion which are distributed in a T shape, wherein the horizontal portion is matched with the horizontal section corresponding to the coal pillar, and the support portion is located at the center line of the horizontal section.
In the mining method for reserving the protective coal pillars in the steeply inclined extra-thick coal seam, preferably, the thickness of the coal seam corresponding to the horizontal part is 4 to 9m, and the thickness of the coal seam corresponding to the supporting part is 8 to 12m.
Preferably, the coal pillars are anchored and protected by a combination of steel belts and anchor rods, wherein a plurality of steel belts are uniformly distributed along the length direction of the coal pillars, 7 anchor rods are equidistantly distributed on each steel belt, and the distance between two adjacent steel belts on the coal pillars is 800mm.
Preferably, after the mining working face is pushed for a certain distance, the coal pillars are reinforced by grouting, the grouting holes are distributed in gaps between the coal pillars and the steel strips, 6 grouting holes are formed in each row, the number of the steel strips corresponding to any two adjacent rows of the grouting holes is 3, and the grouting time lags behind the tunneling progress of the roadway for 15-25 days.
In the mining method for reserving the protective coal pillar in the steeply inclined extra-thick coal seam, preferably, a diamond-shaped metal protecting net is attached to the surface of the coal pillar, and the diamond-shaped metal protecting net is fixed to the surface of the coal pillar through the steel belt.
In the mining method for reserving the protective coal pillar in the steep-dip extra-thick coal seam, preferably, an anchor cable is arranged at a contact position of the coal pillar with the top plate and the bottom plate of the coal seam, so as to limit the contact position of the coal pillar with the top plate and the bottom plate of the coal seam.
In the mining method for reserving the protective coal pillar in the steeply inclined extra-thick coal seam, preferably, the anchor cable is a grouting anchor cable, so as to reinforce the contact surface between the coal pillar and the coal seam roof and the coal seam floor through grouting, and a plurality of first grouting anchor cables longitudinally anchored to the coal seam floor or the coal seam roof are arranged on the lateral edge of the coal pillar; and a plurality of second grouting anchor cables are arranged at the lower edge of the coal seam roof or the coal seam floor corresponding to the coal pillars, and the second grouting anchor cables are perpendicular to the coal seam roof or the coal seam floor.
In the mining method for reserving the protective coal pillars in the steeply inclined extra-thick coal seam, preferably, the height of the mining working face corresponding to each horizontal section is 6m, and once grouting reinforcement is performed on the reserved coal pillars of the lower horizontal section every 3 times of the cycle operation of the coal mining machine.
Has the advantages that: the method can effectively solve the problems of roof instability collapse and surface subsidence caused by a high-stage horizontal sublevel caving coal mining method in an ecological fragile mining area, can effectively control the movement of the roof strata of the coal bed, and has important significance for safely and efficiently mining resources and simultaneously reducing the surface subsidence and protecting the ecological environment.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a face mining layout elevation view of the present invention;
FIG. 2 is a schematic view of the coal pillar support design of the present invention;
FIG. 3 isbase:Sub>A schematic sectional view taken along line A-A of FIG. 1;
FIG. 4 is a front view of an anchoring structure for the contact surface of a coal pillar with the roof and the floor of a coal seam according to the present invention.
In the figure: 1. a coal seam roof; 2. a coal seam floor; 3. a coal pillar; 4. mining a working face; 5. grouting holes; 6. covering rock; 7. a coal seam; 8. mining a working face progress line; 9. a first grouting anchor cable; 10. a second grouting anchor cable; 11. a steel belt; 12. an anchor rod; 31. a horizontal portion; 32. a support portion.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
As shown in fig. 1-4, a mining method for reserving a protective pillar in a steeply inclined extra-thick coal seam includes: the method comprises the following steps that S1, the position of a first mining working face is determined based on occurrence characteristics of a coal seam 7, specifically, a bottom plate of a coal seam overlying rock 6 is used as a top plate of the first mining working face, the first mining working face horizontally extends along the trend of the coal seam 7, the coal seam 7 is divided into a plurality of horizontal sections according to the first mining working face, equipment selection, system arrangement and coal mining operation methods are carried out according to occurrence conditions and working face arrangement modes of the actual coal seam 7, and specifically, a large mining height comprehensive mechanical coal mining method is adopted for mining; step S2, arranging two mining working faces 4 in each horizontal section, tunneling a roadway for each mining working face 4, reserving a coal pillar 3 between the two mining working faces 4 of the same horizontal section during tunneling, supporting a top plate and a bottom plate of each mining working face 4 through the coal pillar 3, and anchoring and protecting the coal pillar 3; when a roadway is excavated, reserving coal pillars 3 between the mining working face top plate and the mining working face bottom plate of the corresponding horizontal segment, and anchoring and protecting the coal pillars 3; the length of the coal pillar 3 corresponds to the length of the mining working face 4, and the problem of surface subsidence caused by roof collapse can be effectively solved by the mining method of reserving the strip-type protective coal pillar 3. In the same horizontal segment, two mining working faces 4 are respectively positioned at two sides of the horizontal segment and extend along the corresponding horizontal segment. S3, in the mining process, adopting a retreating type mining sequence to simultaneously mine two mining working faces 4 of the same horizontal subsection, and grouting and reinforcing the reserved coal pillar 3 corresponding to the top plate of the next horizontal subsection when the mining working faces 4 are pushed for a certain distance; and S4, repeating the steps S2-S3, and mining the plurality of horizontal subsections in sequence. When the mining working face 4 carries out extraction, in order to improve the stability of the reserved coal pillars 3, the bearing capacity of the coal pillars 3 is improved by adopting a grouting reinforcement and anchor protection combined supporting technology. The broken rock blocks are cemented into a whole again through grouting reinforcement, the integrity, the bearing capacity and the stability of the supporting structure are improved, and the existing supporting structure is strengthened. And the slurry is used for filling the coal-rock body cracks, so that the bearing capacity of the supporting structure is improved.
In another optional embodiment, in the step S3, in the mining process, the contact surfaces between the top plate and the bottom plate of the horizontal segment to be mined and the corresponding coal pillars 3 are reinforced, so that the coal pillars 3 are prevented from sliding and destabilizing along the contact surfaces, and the problems of high cost, long processing period, unobvious processing effect and the like caused by the top plate processing and ground backfilling measures in the later stage of the original mining technology are solved.
In another alternative embodiment, the coal pillar 3 extends along the center line of the mining face 4, and the coal pillar 3 includes a horizontal portion 31 and a support portion 32 distributed in a T shape, wherein the horizontal portion 31 matches with the corresponding horizontal section of the coal pillar 3, and the support portion 32 is located at the center line of the horizontal section and extends along the center line of the horizontal section, and the length of the support portion matches with the length of the horizontal section, and the width of the support portion matches with the width of the horizontal section, and the two sides of the horizontal portion 31 respectively contact with the coal seam roof 1 and the coal seam floor 2. The thickness of the coal seam corresponding to the horizontal part 31 is 4-9m, and the thickness of the coal seam corresponding to the supporting part 32 is 8-12m. Specifically, the size parameters of the coal pillar 3 can be determined by testing the physical and mechanical parameters of the coal rock, for example, the thickness of the coal seam corresponding to the horizontal portion 31 can be 4m, 5m, 8m, 9m, and the thickness of the coal seam corresponding to the support portion 32 can be 8m, 9m, 10m, 12m, etc.; the thickness of the coal seam corresponding to the horizontal portion 31 is the longitudinal thickness of the coal seam in fig. 1, and the thickness of the coal seam corresponding to the supporting portion 32 is the horizontal thickness of the coal seam in fig. 1.
In another optional embodiment, the coal pillar 3 is anchored and protected by combining the steel belts 11 and the anchor rods 12, a plurality of steel belts 11 are uniformly distributed along the length direction of the coal pillar 3, wherein 7 anchor rods 12 are equidistantly distributed on each steel belt 11, and the distance between two adjacent steel belts 11 is 800mm.
The steel belt 11 is a W-shaped steel belt 11, and the coal pillar 3 is reinforced by the steel belt 11 combined with the anchor rod 12 in a supporting manner, wherein the W-shaped steel belt 11 may be provided only on the supporting portion 32 of the coal pillar 3, or the steel belt 11 may be bent to correspond to the supporting portion 32 and the horizontal portion 31 of the coal pillar 3, thereby fixing the coal pillar 3.
The diameter of the anchor rod 12
The anchor 12 has a prestress of 150kN. The length is 2.5m, the full length of the resin is anchored, and a W-shaped steel belt 11 and a diamond-shaped metal net are adopted to protect the surface. All the anchor rods 12 are paved perpendicular to the surface of the roadway, 7 anchor rods are arranged in each row, and the row spacing is 800mm.
Determining the pre-tightening force of the anchor rod 12 of the coal pillar 3 to be 150kN according to a coal mine support handbook;
the calculation formula of the length of the high-strength prestressed anchor rod 12 is as follows:
L a ≥L a1 +L a2 +L a3
in the formula: l is a The total length of the anchor 12, mm;
L a1 the exposed length of the anchor rod 12, mm,the value is 100mm;
L a2 the effective length of the anchor rod 12, mm, is 1700mm;
L a3 -the anchor rod 12 stabilizes the length in the coal seam, mm, with a value of 500mm;
therefore, according to the bolt 12 support specification and engineering practice, the highly prestressed bolt 12 is determined to be 2.5m in length.
In the embodiment, the grouting holes 5 are distributed in the gaps between the steel belts 11 corresponding to the coal pillars 3, 6 grouting holes 5 are arranged in each row, the number of the steel belts 11 corresponding to any two adjacent rows of the grouting holes 5 is 3, and the grouting time lags behind the tunneling progress for 15-25 days. The grouting time leads the mining process and the grouting reinforcement process to be staggered in time and space through lagging, and the mining process and the grouting reinforcement process are not interfered with each other in the limited space of the underground roadway. The stability of the surrounding rock is damaged in the process of roadway tunneling, certain disturbance is caused, stress and deformation of the tunneled surrounding rock can be balanced again through lag time, and grouting reinforcement can be performed after deformation of the surrounding rock is stable, so that a better effect can be achieved.
The height of a mining working face 4 corresponding to each horizontal subsection is 6m, and grouting reinforcement is carried out on the reserved coal pillars 3 of the lower horizontal subsection coal seam 7 every 3 times of the mining working face 4 finishes circulation operation (namely the mining working face 4 is pushed by 2.4 m); as shown in fig. 3, 8 is a mining face progress line 8, after mining for a certain distance, grouting holes 5 are drilled in the mined part, and parameters required for concrete grouting reinforcement of the coal pillar 3 are as follows:
grouting time: the roadway grouting is prior to the grouting of the lower horizontal subsection coal seam at the mining working face, specifically, the roadway is arranged on both sides of each mining working face 4, firstly, the roadway is grouted and reinforced, the safety is improved, and the grouting reinforcement is carried out on the coal pillar 3 of the next horizontal subsection after the coal pillar is mined for a certain progress;
grouting pressure: preliminarily determining grouting pressure by using a field hydraulic test, wherein the grouting pressure is 2MPa for example;
grouting amount: in order to ensure that the cracks can be filled and compacted by grouting, the grouting is carried out until no grout is taken in principle;
grouting reinforcement range: the grouting reinforcement range (diffusion radius of the grout) has close relation with the porosity, permeability coefficient and grouting pressure of the coal rock mass, and the diffusion radius of the grout in the fractured coal rock mass under the action of different grouting pressures can be calculated by adopting the following formula:
in the formula: r-slurry diffusion radius, mm;
k is the formation permeability coefficient;
t-grouting duration, s;
h-grouting pressure in centimeters of water, cm;
r 0 -the radius of the slip casting pipe, cm;
beta-relative viscosity of the slurry, s;
n-porosity of rock formation,%;
when the initial grouting pressure is 2MPa, the diffusion radius of the slurry is 1.9m.
Depth of grouting hole 5: the depth of the grouting holes 5 mainly depends on the surrounding rock crushing range of the roadway, and according to engineering practice, the depth of the grouting holes 5 of the roadway based on cement slurry is generally designed to be 3m;
grouting materials: the composite slurry is prepared by mixing cement, fly ash, clay, quicklime, sodium sulfate and water according to the mass ratio of 1.45;
grouting hole 5 arrangement parameters: the pitch of the injection holes 5 can be designed to be 3 to 4m, preferably 3m, in general, and the pitch between the injection holes 5 is selected in close relation to the diffusion radius. The pitch of the grouting holes 5 is such that the diffusion ranges of the 2 grouting holes 5 are crossed to a certain extent, and a coefficient of 0.65-0.75 can be adopted, namely the row pitch of the grouting holes 5 is generally 1.95-3 m. Each work surface is provided with 8 grouting holes 5 per row, as shown in fig. 3.
A diamond-shaped metal protecting net is attached to the surface of the coal pillar 3 and is fixed on the surface of the coal pillar 3 through a steel belt 11. The strength of the coal pillar 3 is enhanced through the diamond metal protecting net, and the stability of the coal pillar 3 is improved.
In another optional embodiment, the contact surfaces of the top plate and the bottom plate and the corresponding coal pillars 3 are reinforced by grouting anchor cables, and the anchor cables are arranged at the contact positions of the coal pillars 3 and the coal seam top plate 1 and the coal seam bottom plate 2, so as to limit the coal pillars 3 and the coal seam top plate and the coal seam bottom plate. Wherein, accomplish 3 times of circulation operation (at every turn the circulation operation tunnelling distance is 2.4 m) and carry out the slip casting reinforcement to coal seam roof, bottom plate and 3 contact surfaces of coal pillar at first, every row of contact surface arranges a slip casting hole 5, and the 5 angles of slip casting hole are 45, and under the condition that coal seam roof 1 and 2 inclination of coal seam bottom plate are 45 promptly, 5 angles of slip casting hole are vertical arrangement or horizontal arrangement to make the slip casting hole 5 and coal seam roof 1 or 2 inclination of coal seam bottom plate be 45.
The anchor cables are grouting anchor cables, so that the contact surfaces of the coal pillar, the coal seam roof and the coal seam floor are reinforced through grouting, and a plurality of first grouting anchor cables 9 which are longitudinally anchored on the coal seam floor 2 or the coal seam roof 1 are arranged on the lateral edges of the coal pillar 3; and a plurality of second grouting anchor cables 10 are arranged at the lower edge of the coal seam roof 1 or the coal seam floor 2 corresponding to the coal pillars 3, the second grouting anchor cables 10 are perpendicular to the coal seam roof 1 or the coal seam floor 2 and can be arranged according to actual conditions, but the second grouting anchor cables 10 and the coal seam roof 1 or the coal seam floor 2 are controlled to be between 90 and 100 degrees.
The diameter of the anchor cable
The length of the high-strength prestressed anchor cable is 7m and 13.8m, and the end part of the resin is anchored. The row spacing of the anchor cables is 2.4m, the interval is 1m, and 6 anchor cables are arranged in each row. The prestress of the anchor cable is 200-250 kN.
The length calculation formula of the high-strength prestressed anchor cable is as follows:
L b ≥L b1 +L b2 +L b3
in the formula: l is b -total cable length, mm;
L b1 the exposed length of the anchor cable is 300mm;
L b2 -the thickness of the anchor cable suspending loose rock stratum is 5000mm and 12000mm;
L b3 -anchorsThe length in the cable stabilized coal layer, mm, is 1500mm;
therefore, according to anchor cable support specifications and engineering practices, the lengths of the high-prestress anchor cables are determined to be 7.0m and 13.8 m.
The high-prestress anchor rods 12 (cables) are used in the coal pillar 3 support, prestress is diffused through support members such as steel belts 11, the effect of enhancing the strength of surrounding rocks is achieved, deformation of a roadway is prevented, meanwhile, the anchor cables also have the effect of controlling separation of a composite top plate and downward sliding of a top plate rock stratum through angle adjustment, and therefore the problems of top plate collapse and ground surface subsidence caused by a high-stage horizontal subsection top coal caving coal mining method are solved.
It should be understood that the above description is only exemplary, and the embodiments of the present application do not limit the present invention.
The above description is only exemplary of the invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the invention is intended to be covered by the appended claims.
Claims (6)
1. A mining method for reserving protective coal pillars on a steep and ultra-thick coal seam is characterized by comprising the following steps:
the method comprises the following steps that S1, the position of a first mining working face is determined based on coal seam occurrence characteristics, the first mining working face horizontally extends along the trend of the coal seam, and the coal seam is divided into a plurality of horizontal sections according to the first mining working face;
step S2, arranging two mining working faces in each horizontal section, tunneling a roadway for each mining working face, reserving a coal pillar between the two mining working faces of the same horizontal section during tunneling the roadway, extending the coal pillar along the center line of the mining working faces, supporting the top plate and the bottom plate of the mining working faces through the coal pillar, and anchoring and protecting the coal pillar;
s3, adopting a backward stoping sequence to simultaneously stope two mining working faces of the same horizontal section, wherein the stoping method adopts a large mining height comprehensive mechanical coal mining method, and grouting and reinforcing the reserved coal pillar corresponding to the top plate of the next horizontal section every time the mining working faces are pushed for a certain distance; the coal pillar comprises a horizontal part and a supporting part which are distributed in a T shape, wherein the horizontal part is matched with the horizontal section corresponding to the coal pillar, and the supporting part is positioned at the central line position of the horizontal section;
s3, reinforcing the contact surfaces of the top plate and the bottom plate of the horizontal subsection to be mined and the corresponding coal pillars in the stoping process;
arranging anchor cables at the contact positions of the coal pillars and the coal seam roof and the coal seam floor so as to limit the coal pillars and the coal seam roof and the coal seam floor;
the working face completes 3 times of circulating operation to firstly carry out grouting reinforcement on contact surfaces of the top and bottom plates of the coal seam and the coal pillars, each row of contact surfaces is provided with a grouting hole, the angle of each grouting hole is 45 degrees, namely under the condition that the inclination angle of the top plate of the coal seam and the bottom plate of the coal seam is 45 degrees, the angles of the grouting holes are vertically arranged or transversely arranged, so that the inclination angle of each grouting hole and the top plate of the coal seam or the bottom plate of the coal seam is 45 degrees;
the anchor cables are grouting anchor cables, the contact surface of grouting and the corresponding coal pillar is reinforced, and a plurality of first grouting anchor cables longitudinally anchored on a coal seam bottom plate or a coal seam top plate are arranged at the end part of the coal pillar; a plurality of second grouting anchor cables are arranged at the lower edge of the coal pillar corresponding to the coal seam roof or the coal seam floor, and the second grouting anchor cables are perpendicular to the coal seam roof or the coal seam floor; and S4, repeating the steps S2-S3, and mining the plurality of horizontal subsections in sequence.
2. A mining method for reserving and protecting coal pillars at a steep extra-thick coal seam according to claim 1, wherein the thickness of the coal seam corresponding to the horizontal part is 4-9m, and the thickness of the coal seam corresponding to the supporting part is 8-12m.
3. The mining method for reserving and protecting the coal pillars in the steeply inclined and extremely thick coal seam according to claim 1, wherein the coal pillars are anchored and protected by combining steel belts and anchor rods, wherein a plurality of steel belts are uniformly distributed along the length direction of the coal pillars, 7 anchor rods are equidistantly distributed on each steel belt, and the distance between two adjacent steel belts on the coal pillars is 800mm.
4. The method for exploiting the steeply inclined and extremely thick coal seam with the protective coal pillars reserved thereon according to claim 3, wherein the coal pillars are reinforced by grouting after the working face is advanced for a certain distance, the number of grouting holes is 6 in each row, the number of the steel strips corresponding to any two adjacent rows of grouting holes is 3, and the grouting time lags behind the tunneling progress for 15-25 days.
5. The mining method for reserving and protecting the coal pillar in the steeply inclined and extremely thick coal seam as claimed in claim 3, wherein a diamond-shaped metal protecting net is attached to the surface of the coal pillar, and the diamond-shaped metal protecting net is fixed to the surface of the coal pillar through the steel belt.
6. A mining method for reserving and protecting coal pillars at a steep extra-thick coal seam according to any one of claims 1 to 5, characterized in that the height of a mining working face corresponding to each horizontal section is 6m, and the reserved coal pillars at the lower horizontal section are reinforced by grouting once every 3 times of the cycle operation of a coal mining machine.
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| CN104847351B (en) * | 2015-05-31 | 2017-07-25 | 西安科技大学 | A kind of severe inclined thick coal seam longwall top coal caving controls top method with three-dimensional |
| CN106246184A (en) * | 2016-08-24 | 2016-12-21 | 神华集团有限责任公司 | A kind of recovery method of half-edge coal seam |
| CN106939789B (en) * | 2017-03-20 | 2019-08-20 | 中国神华能源股份有限公司 | A kind of pair of super high seam carries out the separate zone production technique of separate zone production |
| CN108150172A (en) * | 2018-01-18 | 2018-06-12 | 山东科技大学 | A kind of single method of mining coal from heavy pitch thick coal seam |
| CN109025998A (en) * | 2018-08-02 | 2018-12-18 | 缪协兴 | A kind of thick sandstone recovery method using goaf solid filling technology |
| CN109209495B (en) * | 2018-09-13 | 2020-08-04 | 天地科技股份有限公司 | Roof cutting and pressure relief protection method on stoping surface of fully mechanized coal mining face |
| CN110067558A (en) * | 2019-04-16 | 2019-07-30 | 中国矿业大学 | A kind of severe inclined thick coal seam stope drift active workings joint release prevention and treatment impulsion pressure method |
| CN210118152U (en) * | 2019-07-10 | 2020-02-28 | 重庆大学 | Steep-inclined thick coal seam small-coal-pillar gob-side entry retaining high-side coal body small-angle anchoring structure |
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