阅读说明：本技术 一种分区开采的露天矿端帮压煤回收方法 (Method for recovering end slope pressing coal of strip mine for partition mining ) 是由 王小红 杨国宇 崔小娟 陈涛 于 2021-08-20 设计创作，主要内容包括：本发明公开了一种分区开采的露天矿端帮压煤回收方法,端帮包括到界端帮和共同端帮,采用端帮采煤机作为主要开采设备,技术成熟成本可控；随采随填充,有效保证开采巷道及开采区域边坡稳定性；回填采用膏体填充和露天矿剥离物填充组合方式,降低回填成本,保证回填效果；采用分层开采,减少开采对端帮的扰动,同时实现厚煤层、巨厚煤层的全高度开采；设置排土垫层,提高开采巷道施工水平,增加施工场地,有利于设备布置；设置过渡排土桥可以连通露天矿坑底和内排土场,同时配合排土垫层,实现坑底逐步内排,减少甚至消除端帮压煤开采对露天矿排土的影响,不增加排土成本；对共同端帮实施交叉开采,提高压煤回收率,保证端帮稳定性。(The invention discloses a method for recovering end slope pressing coal of a strip mine for zonal mining, wherein the end slope comprises a boundary end slope and a common end slope, and an end slope coal mining machine is adopted as main mining equipment, so that the mature technology cost is controllable; the stability of the mining roadway and the mining area slope is effectively ensured along with mining and filling; the backfill adopts a combination mode of paste filling and strip mine stripping filling, so that the backfill cost is reduced, and the backfill effect is ensured; the method adopts the layered mining, reduces the disturbance of mining to the end slope, and simultaneously realizes the full-height mining of the thick coal seam and the huge thick coal seam; the arrangement of the dumping cushion layer improves the construction level of the mining roadway, increases the construction site and is beneficial to equipment arrangement; the transition dumping bridge is arranged to communicate the pit bottom and the inner dumping field of the strip mine, and meanwhile, the dumping cushion layer is matched to realize gradual inner dumping of the pit bottom, so that the influence of end slope pressing coal mining on strip mine dumping is reduced and even eliminated, and the dumping cost is not increased; and cross mining is carried out on the common end slope, so that the coal pressing recovery rate is improved, and the stability of the end slope is ensured.)

1. A method for reclaiming the end slope pressing coal of the strip mine for mining in different regions, wherein the end slope comprises an end slope (2) from a boundary and a common end slope (15),

the mining method of the boundary end slope (2) comprises the following steps,

the method comprises the following steps: after a boundary end slope (2) is formed by excavating at one side close to a boundary (1) of the strip mine, delaying the propulsion of an earth discharge field (3) in the strip mine, and excavating a first mining cave (5) on an end slope pressing coal (6) at one side of a pit bottom (4) of the strip mine close to the earth discharge field (3) in the strip mine to mine the end slope pressing coal (6);

step two: stopping mining when the length of the first mining cave (5) extends to reach the position of H/tan alpha when the H/tan alpha is less than 300 m; when the H/tan alpha is larger than or equal to 300m, stopping mining when the length of the first mining cave (5) extends to 300 m; h is the height difference between the bottom plate of the first mining cave (5) and the surface of the strip mine, and alpha is the slope angle of the slope from the first mining cave (5) to the boundary end slope (2);

step three: hard rock blocks stripped from strip mines are transported to the tail end of the first mining cave (5) and backfilled in the goaf, and concrete can be simultaneously transported to the tail end of the first mining cave (5) to backfill the goaf in the area with weak geological conditions;

step four: during the forward propelling mining of the first mining cave (5), a second mining cave (7) is synchronously arranged at one side of the first mining cave (5) close to the working surface of the strip mine, a supporting coal pillar (17) is reserved between the second mining cave (7) and the first mining cave (5), and the width of the supporting coal pillar (17) is 2 times of the height of the first mining cave (5);

step five: during the forward propelling mining of the second mining cave (7), a third mining cave (8) is synchronously arranged at one side of the second mining cave (7) close to the working surface of the strip mine, a supporting coal pillar (17) is reserved between the third mining cave (8) and the second mining cave (7), and the width of the supporting coal pillar (17) is 2 times of the height of the second mining cave (7); by analogy, the steps are sequentially distributed to the nth mining cave, and each mining cave is backfilled immediately after mining is finished;

step six: after the first mining cave (5) and the second mining cave (7) are backfilled, discharging soil at the bottom (4) of the strip mine pit in the positions corresponding to the mouths of the first mining cave (5) and the second mining cave (7) to form a first layer of soil discharging cushion layer (9);

step seven: a second layer of first mining cave (10) is arranged right above a reserved supporting coal pillar (17) between the first mining cave (5) and the second mining cave (7);

step eight: with the completion of backfilling of the third mining cave (8), extending the first layer of dumping cushion layer (9) to completely cover the cave mouth of the third mining cave (8), and arranging a second layer of second mining cave (11) right above a reserved supporting coal pillar (17) between the second mining cave (7) and the third mining cave (8);

step nine: after the first mining cave (10) and the second mining cave (11) of the second layer are backfilled, dumping is carried out to form a second-layer dumping cushion layer (18), and a third-layer first mining cave (12) is arranged right above a reserved supporting coal pillar (17) between the first mining cave (10) of the second layer and the second mining cave (11); arranging the nth chamber of the third layer by analogy;

step ten: in the same way, the dumping forms the (N-1) th dumping cushion layer, the (N) th mining cave is arranged until all the end slope pressing coal (6) can be mined, the propelling speed of the dumping cushion layer is matched with the backfilling completion speed of the mining cave at the same layer, and the dumping cushion layer moves forward to cover the mining cave after each backfilling of one mining cave is completed;

the end slope at the junction position of the adjacent X mining area (13) and the X +1 mining area (14) is a common end slope (15), the mining method of the common end slope (15) is as follows,

step A: when an X mining area (13) is mined, construction is carried out on the common end wall (15) according to the process of arranging mining tunnels on the boundary end wall (2);

the length of the underground mining on the common end wall (15) is determined according to the following method:

stopping mining when the length of the mining cave extends to H/tan beta + H/tan gamma when H/tan beta + H/tan gamma is less than 300 m;

when H/tan beta + H/tan gamma is larger than or equal to 300m, stopping mining when the length of the mining cave extends to 300 m;

h is the height difference between the mining cave bottom plate and the surface of the strip mine, beta is the slope angle of the left side wall of the common end wall where the mining cave is located, and gamma is the slope angle of the right side wall of the common end wall where the mining cave is located;

and B: when an X +1 th mining area (14) is mined, construction is carried out on a common end wall according to the process of arranging a mining cave on the boundary end wall (2); the chamber of the X +1 mining area (14) and the chamber of the X mining area (13) are arranged in a staggered way.

2. The method for reclaiming highwall coal briquettes in a surface mine for district mining according to claim 1, wherein the method comprises the following steps: in the first step, the first mining cave (5) is dug at the first layer of the coal pressing (6) of the end slope at the lowest layer of the boundary end slope (2) and is 30m away from the slope bottom line of the step at the lowest part of the dump (3) in the strip mine.

3. The method for reclaiming highwall coal briquettes in a surface mine for district mining according to claim 1, wherein the method comprises the following steps: in the sixth step, the soil discharging height of the first soil discharging cushion layer (9) is 2-3m higher than that of the first underground mining layer (5).

4. The method for reclaiming highwall coal briquettes in a surface mine for district mining according to claim 1, wherein the method comprises the following steps: and the underground mining is provided with a depression angle of 3 per mill along the propelling direction.

5. The method for reclaiming highwall coal briquettes in a surface mine for district mining according to claim 1, wherein the method comprises the following steps: and in the process of constructing the underground mining from the boundary end slope (2) and the common end slope (15), constructing a slope-shaped transition dumping bridge (16) of a dumping step from the open-pit bottom (4) to the dump (3) in the open-pit mine by utilizing the open-pit mine stripping object in the middle of the open-pit mine bottom (4).

6. The method for reclaiming highwall coal briquettes in a surface mine mined according to claim 5, wherein the method comprises the steps of: gradually discharging strip mine stripping materials from two sides of a road of a transition dump bridge (16) to an end slope in the process of mining the end slope coal pressing (6) by the mining cave, and stopping discharging when the bottom boundary of the discharging materials is 80m away from a mining cave mouth under construction; after the first mining cave of the Nth layer is filled, the whole open pit inner soil discharging field (3) starts to follow the speed of the completion of the backfilling of the mining cave of the Nth layer, a plurality of soil discharging step tracking type soil discharging is carried out from the soil discharging cushion layer of the Nth-1 layer to the highest step of the inner soil discharging field, the plurality of steps are sequentially pushed forward, and the slope bottom line of the tracking soil discharging step with the same height is kept to be not lower than 30m away from the nearest constructed mining cave.

Technical Field

The invention relates to a method for recovering end slope pressing coal, in particular to a method for recovering end slope pressing coal of strip mine in zonal mining.

Background

Strip mining is an important coal mining technology, and has obvious economic advantages in mining of thick coal seams and huge thick coal seams. Currently, a large number of open pit coal mines are distributed in the north and most areas in the northwest of China, and the thickness of coal seams of the open pit coal mines is dozens of meters or even hundreds of meters. The partition mining effectively reduces the initial investment cost of a coal mine, realizes the maximum recovery of coal resources, but the large number of the partition mining end slopes also cause the coal pressing of the end slope to be a new problem seriously, and the coal pressing of the end slope exceeds 20 ten thousand tons when the end slope extends for 100m and is calculated by the thickness of 50m and the inclination angle of the end slope of 35 degrees. Therefore, how to realize the recovery of the end slope pressing coal of the strip mine for mining the thick coal seam and the huge thick coal seam in a partition manner has important significance for improving the recovery rate of strip mine resources and improving enterprise benefits. At present, for the recovery of end slope pressed coal, a steep-slope mining mode is often adopted, namely, multiple coal mining is realized by increasing the slope angle of the end slope, but the method is limited by the safety problem, the steep-slope mining angle is not too large, and the resource recovery efficiency is still not high.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for recovering open-pit mine end slope pressing coal in partition mining, which is safe in end slope pressing coal recovery and high in end slope pressing coal recovery efficiency.

In order to achieve the purpose, the invention provides the following technical scheme: a method for recovering the end slope pressing coal of the strip mine for mining in different regions comprises the following steps,

the method comprises the following steps: excavating at one side close to the boundary of the strip mine to form a boundary end slope, lagging the propulsion of the dump in the strip mine, and excavating a first mining cave on the end slope pressing coal at one side close to the dump in the strip mine at the bottom of the strip mine pit to mine the end slope pressing coal;

step two: when H/tan alpha is less than 300m, stopping mining when the length of the first mining cave extends to reach the position of H/tan alpha; when H/tan alpha is larger than or equal to 300m, stopping mining when the length of the first mining cave extends to 300 m; h is the height difference between the first mining cave bottom plate and the surface of the strip mine, and alpha is the slope angle from the first mining cave to the boundary end slope;

step three: hard rock blocks stripped from strip mines are transported to the tail end of the first mining cave and backfilled into the goaf, and concrete can be simultaneously transported to the tail end of the first mining cave to backfill the goaf in the area with weak geological conditions;

step four: during the forward propelling mining of the first mining cave, a second mining cave is synchronously arranged at one side of the first mining cave close to the working surface of the strip mine, a supporting coal pillar is reserved between the second mining cave and the first mining cave, and the width of the supporting coal pillar is 2 times of the height of the first mining cave;

step five: during the forward propelling mining period of the second mining cave, a third mining cave is synchronously arranged at one side of the second mining cave close to the working surface of the strip mine, a supporting coal pillar is reserved between the third mining cave and the second mining cave, and the width of the supporting coal pillar is 2 times of the height of the second mining cave; by analogy, the steps are sequentially distributed to the nth mining cave, and each mining cave is backfilled immediately after mining is finished;

step six: after the first mining cave and the second mining cave are backfilled, discharging soil at the bottom of the open pit in the positions corresponding to the openings of the first mining cave and the second mining cave to form a first-layer soil discharging cushion layer;

step seven: arranging a second layer of first mining cave right above a reserved supporting coal pillar between the first mining cave and the second mining cave;

step eight: extending the first layer of dumping cushion layer to completely cover the port of the third mining cave along with the completion of backfilling of the third mining cave, and arranging a second layer of second mining cave right above a reserved supporting coal pillar between the second mining cave and the third mining cave;

step nine: after the backfilling of the first mining cave of the second layer and the second mining cave of the second layer is finished, dumping to form a second-layer dumping cushion layer, and arranging a third-layer first mining cave right above a reserved supporting coal pillar between the first mining cave of the second layer and the second mining cave of the second layer; arranging the nth chamber of the third layer by analogy;

step ten: in the same way, the dumping forms an N-1 th dumping cushion layer, the Nth mining cave is arranged until all the end slope pressing coal can be mined, the propelling speed of the dumping cushion layer is matched with the backfilling completion speed of the mining cave at the same layer, and the dumping cushion layer follows forwards to cover the mining cave after each backfilling of one mining cave is completed;

the end slope at the junction position of the adjacent X mining area and the X +1 mining area is a common end slope, and the common end slope mining method comprises the following steps,

step A: when the X mining area is mined, constructing on the common end wall according to the process of arranging the mining cave on the boundary end wall;

the length of the upper underground mining at the common end wall is determined according to the following method:

stopping mining when the length of the mining cave extends to H/tan beta + H/tan gamma when H/tan beta + H/tan gamma is less than 300 m;

when H/tan beta + H/tan gamma is larger than or equal to 300m, stopping mining when the length of the mining cave extends to 300 m;

h is the height difference between the mining cave bottom plate and the surface of the strip mine, beta is the slope angle of the left side wall of the common end wall where the mining cave is located, and gamma is the slope angle of the right side wall of the common end wall where the mining cave is located;

and B: when an X +1 th mining area is mined, construction is carried out on a common end wall according to the process of arranging mining tunnels on the boundary end wall; and the chamber of the X +1 mining area and the chamber of the X mining area are arranged in a staggered manner.

Further, in the step one, the first mining cave is dug at the first layer of the coal pressing of the end slope at the lowest layer of the boundary end slope, and the distance between the first mining cave and the slope bottom line of the step at the lowest part of the earth discharge field in the strip mine is 30 m.

Further, in the sixth step, the discharging height of the first discharging cushion layer is 2-3m higher than that of the first underground mining.

Further, the underground mining is provided with a depression angle of 3 per thousand in the propelling direction.

Further, in the process of constructing the mining cave to the boundary end slope and the common end slope, a slope-shaped transition dumping bridge from the bottom of the open pit to a dumping site dumping step in the open pit is constructed by utilizing an open pit stripper in the middle of the bottom of the open pit.

Further, in the process of carrying out end slope coal pressing mining on the mining cave, strip mine stripping materials are gradually discharged from two sides of a transition dump bridge road to end slopes, and when the bottom boundary of the stripping materials is 80m away from a mining cave mouth under construction, the dumping is stopped; after the first mining cave of the Nth layer is filled, the whole of the dumping ground in the strip mine starts to follow the speed of the completion of the backfilling of the mining cave of the Nth layer, a plurality of dumping step tracking dumping is carried out from the dumping cushion of the Nth-1 layer to the highest step of the dumping ground in the inner dumping ground, the steps are sequentially pushed forward, and the slope bottom line of the tracking dumping step with the same elevation is kept to be not less than 30m away from the nearest mining cave under construction.

Compared with the prior art, the end slope coal mining machine is adopted as main mining equipment, so that the mature technology is controllable in cost; the stability of the mining roadway and the mining area slope is effectively ensured along with mining and filling; the backfill adopts a combination mode of paste filling and strip mine stripping filling, so that the backfill cost is reduced, and the backfill effect is ensured; the method adopts the layered mining, reduces the disturbance of mining to the end slope, and simultaneously realizes the full-height mining of the thick coal seam and the huge thick coal seam; the soil discharging cushion layer is arranged, so that the elevation of the underground mining construction is improved, the construction site is increased, and the equipment arrangement is facilitated; the transition dumping bridge is arranged to communicate the pit bottom and the inner dumping field of the strip mine, and meanwhile, the dumping cushion layer is matched to realize gradual inner dumping of the pit bottom, so that the influence of end slope pressing coal mining on strip mine dumping is reduced and even eliminated, and the dumping cost is not increased; and cross mining is carried out on the common end slope, so that the coal pressing recovery rate is improved, and the stability of the end slope is ensured.

Drawings

FIG. 1 is an overall schematic view of an end slope coal briquetting recovery scheme of the present invention;

FIG. 2 is a schematic view of a mining configuration of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 1;

FIG. 4 is a schematic illustration of a common highwall of the present invention;

in the figure: 1. the border of the strip mine; 2. to the boundary end help; 3. an earth discharge field in the strip mine; 4. the bottom of the open pit; 5. a first underground mining; 6. pressing coal at the end slope; 7. a second underground mining; 8. a third underground mining; 9. a first dumping cushion layer; 10. the first mining cave of the second floor; 11. a second layer of second mining tunnels; 12. a third layer of first mining cave; 13. the Xth mining area; 14. an X +1 th mining area; 15. common end upper; 16. a transitional refuse dump bridge; 17. supporting the coal pillar; 18. and the second layer of soil discharging cushion layer.

Detailed Description

The invention will be further explained with reference to the drawings.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: a method of reclaiming contour mine end slope coal briquettes for zonal mining, the end slope comprising a boundary end slope 2 and a common end slope 15.

As shown in fig. 1 and 2, the boundary-to-boundary highwall 2 stratified mining method is that after the boundary highwall 2 is excavated and formed on the side close to the boundary 1 of the open-pit mine, the dump 3 in the open-pit mine is delayed (or "suspended") from advancing, a first mining cave 5 is dug on the highwall pressing coal 6 on the side of the pit bottom 4 close to the dump 3 in the open-pit mine, and the highwall pressing coal 6 is mined; the first mining cave 5 cuts the first layer of the end slope pressing coal 6 at the lowest layer of the boundary end slope 2, and is 30m away from the slope bottom line of the step at the lowest part of the earth discharge field 3 in the strip mine. The height of the first underground mining cave 5 is 3-5m, the section of the first underground mining cave 5 is initially rectangular, the top of the first underground mining cave is trimmed into an arch shape to improve the bearing capacity and stability, the diameter of the arch shape is the same as the width of the underground mining cave, the value range is 3-5m, and an end-wall coal mining machine, a conveyor, a ventilator and a drainage pump are arranged in the first underground mining cave 5; the end slope coal mining machine starts to advance from the cave mouth of the first cave 5 to the direction vertical to the side slope of the boundary end slope 2 to the boundary 1 of the strip mine, and the conveyor, the ventilator and the drainage pump synchronously follow the end slope coal mining machine to extend into the cave; as the first pit 5 advances to mine the end face coal 6.

H is the height difference between the bottom plate of the first mining cave 5 and the surface of the strip mine, and alpha is the slope angle from the boundary end wall 2 to which the first mining cave 5 is positioned; when the H/tan alpha is less than 300m, stopping mining when the length of the first mining cave 5 extends to reach the position of the H/tan alpha (namely the vertical projection of the surface mine boundary 1 on the end slope pressing coal 6); when H/tan alpha is larger than or equal to 300m, stopping mining when the length of the first mining cave 5 extends to 300 m.

After the first mining cave 5 is mined out, all equipment except the conveyor is withdrawn, hard rock blocks stripped from the strip mine are transported to the tail end of the first mining cave 5 by the conveyor and backfilled into the mined out area, and concrete can be simultaneously transported to the tail end of the first mining cave 5 to backfill the mined out area in the area with weak geological conditions, so that the filling rate of the mining cave is improved; and (5) synchronously withdrawing the conveyor to the underground opening along with the continuous backfilling, and recycling the equipment.

During the forward propelling mining of the first mining cave 5, synchronously arranging a second mining cave 7 at one side of the first mining cave 5 close to the working surface of the strip mine, reserving a supporting coal pillar 17 between the second mining cave 7 and the first mining cave 5, wherein the width of the supporting coal pillar 17 is 2 times of the height of the first mining cave 5, and the mining backfill process and the size parameter determination method of the second mining cave 7 are the same as those of the first mining cave 5; during the forward propelling mining of the second mining cave 7, a third mining cave 8 is synchronously arranged at one side of the second mining cave 7 close to the working surface of the strip mine, a supporting coal pillar 17 is reserved between the third mining cave 8 and the second mining cave 7, the width of the supporting coal pillar 17 is 2 times of the height of the second mining cave 7, and the mining backfill process and the size parameter determination method of the third mining cave 8 are the same as those of the second mining cave 7; and by analogy, the steps are sequentially arranged to the nth mining cave, and each mining cave is backfilled immediately after mining is finished. The first mining cave 5 exceeds the second mining cave 7 by a certain distance in the advancing length, namely when the first mining cave 5 advances to mine for a certain distance (the design length of the mining cave is not reached), the second mining cave 7 is arranged immediately, and the like, and then the third mining cave 8 is continuously arranged, and the adjacent mining caves are in a tracking state in sequence.

After the first mining cave 5 and the second mining cave 7 are backfilled, the bottom 4 of the open pit in the corresponding positions of the mouths of the first mining cave 5 and the second mining cave 7 is discharged to form a first layer soil discharging cushion layer 9, and the soil discharging height of the first layer soil discharging cushion layer 9 is 2-3m higher than that of the first mining cave 5; lifting the end slope coal mining machine to the surface of the first layer of dumping cushion 9 for subsequent mining; and a second layer of the first mining cave 10 is arranged right above a reserved supporting coal pillar 17 between the first mining cave 5 and the second mining cave 7, and the mining backfill process and the size parameter determination method of the second layer of the first mining cave 10 are the same as those of the first mining cave 5.

With the completion of the backfilling of the third mining cave 8, continuously extending the first layer of soil discharging cushion layer 9 to completely cover the cave mouth of the third mining cave 8, and arranging a second layer of second mining cave 11 right above a reserved supporting coal pillar 17 between the second mining cave 7 and the third mining cave 8; the mining backfill process and the size parameter determination method of the second layer of the second mining cave 11 are the same as those of the first mining cave 5.

After the backfilling of the first mining cave 10 of the second layer and the second mining cave 11 of the second layer is finished, earth is arranged on the first earth cushion 9 in the corresponding position of the cave mouth of the first mining cave 10 of the second layer and the second mining cave 11 of the second layer according to the forming method of the first earth cushion 9 formed by earth discharge to form a second earth cushion 18, and a third layer of the first mining cave 12 is arranged right above the reserved supporting coal pillar 17 between the first mining cave 10 of the second layer and the second mining cave 11 of the second layer; and the process is arranged to the nth chamber of the third layer by analogy; and by analogy, the dumping forms an N-1 th dumping cushion layer, the Nth mining cave is arranged until all the end slope pressing coal 6 can be mined, the propelling speed of the dumping cushion layer is matched with the backfilling completion speed of the mining cave at the same layer, the dumping cushion layer is advanced to cover the mining cave after each backfilling of the mining cave is completed, and the dumping cushion layer is 2-3m higher than the mining cave covered by the dumping cushion layer.

As shown in fig. 4, the end slope at the junction position of the adjacent X-th mining area 13 and the X + 1-th mining area 14 is a common end slope 15, and the common end slope 15 mining method is that when the X-th mining area 13 is mined, construction is performed on the common end slope 15 according to the process of arranging mining tunnels on the boundary end slope 2; the process of mining and backfilling the underground cave on the common end wall 15 is the same as the process of mining and backfilling the underground cave on the boundary end wall 2.

The length of the underground mining on the common end wall 15 is determined according to the following method: when H/tan beta + H/tan gamma is less than 300m, stopping mining when the length of the mining cave extends to H/tan beta + H/tan gamma, and enabling the length of the mining cave to penetrate through the common end wall 15; when H/tan beta + H/tan gamma is larger than or equal to 300m, stopping mining when the length of the mining cave extends to 300m, wherein the length of the mining cave does not run through the common end wall 15; h is the height difference between the mining cave bottom plate and the surface of the strip mine, beta is the slope angle of the left side wall of the common end wall where the mining cave is located, and gamma is the slope angle of the right side wall of the common end wall where the mining cave is located. And the chamber mining filling on one side of the X mining area 13 is filled with paste, so that higher filling rate and higher filling strength can be realized.

When an X +1 th mining area 14 is mined, constructing and arranging the mining cave on the common end wall according to the process of arranging the mining cave on the boundary end wall 2; the chamber of the X +1 mining area 14 and the chamber of the X mining area 13 are arranged in a staggered mode, namely, the supporting coal pillars 17 reserved in the X mining area 13 are mined from the X +1 mining area 14, and the resource recovery rate is improved.

In the process of constructing the mining cave to the boundary end slope 2 and the common end slope 15, a slope-shaped transition dumping bridge 16 of a dumping step from the bottom 4 of the open-pit mine to the dumping field 3 in the open-pit mine is constructed in the middle of the bottom 4 of the open-pit mine by utilizing an open-pit mine stripping object, the initial width of the transition dumping bridge 16 is the width of two lanes of the open-pit mine, the optimal width is 40m, and the gradient is not more than 8%.

As shown in fig. 3, in the process of mining the end slope pressing coal 6 by the mining cave, strip mine stripping materials are gradually discharged from two sides of the road of the transition dump bridge 16 to the end slope, and when the bottom boundary of the stripping materials is 80m away from the opening of the mining cave under construction, the discharging is stopped; after the first mining cave of the Nth layer is filled, the whole dumping ground 3 in the strip mine starts to follow the speed of the completion of the backfilling of the mining cave of the Nth layer, a plurality of dumping step tracking dumping is carried out from the dumping cushion of the Nth-1 layer to the highest step of the dumping ground, the steps are sequentially pushed forward, and the slope bottom line of the tracking dumping step with the same elevation is kept to be not lower than 30m away from the nearest mining cave under construction.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any minor modifications, equivalent replacements and improvements made to the above embodiment according to the technical spirit of the present invention should be included in the protection scope of the technical solution of the present invention.