A method for supporting solid filling of coal gangue in goaf

Abstract

The present invention describes a method for compacting, top-connecting, gridding, and supporting coal gangue in goaf areas. Specifically, high-strength coal gangue concrete filling materials and pure gangue non-strength filling materials are adjusted through a control system, and the two materials are cross-sprayed to form a mesh structure state in the goaf that combines a high-strength grid support system with non-strength grid filling. The beneficial effects of the present invention are: the gangue mountain can be eliminated; the damage to the roof and floor plates can be reduced or eliminated, and the outflow of water from the roof and floor plates can be reduced; the outflow of gas can be reduced; the effect of retaining the two lanes can be ensured, the cost of retaining the lanes can be reduced, and coal pillar-free mining can be realized, the recovery rate of coal resources can be improved, the amount of tunnel excavation can be reduced, and the tension of mining and excavation can be alleviated; the amount of movement of the roof and floor plates in the goaf area can be greatly reduced or eliminated, the pressure of the roof and floor plates can be reduced, and good conditions can be created for the next layer mining; the air circulation in the goaf can be effectively prevented to avoid the spontaneous combustion of coal gangue and the spontaneous combustion of abandoned coal; and huge economic benefits can be brought to the enterprise.

Description

Technical Field

[0001] The invention belongs to the technical field of mine goaf filling, and in particular relates to a goaf coal gangue compacting, top connection, gridding, and supporting entity filling method. Background Art

[0002] The filling of coal gangue in goaf is a subsidiary project of coal mining with a large capital investment. How to exchange this investment for greater economic benefits is one of the focuses of the present invention.

[0003] The purpose of filling the goaf with coal gangue is, firstly, to eliminate the gangue mountain, that is, to eliminate the economic burden brought by environmental pollution, eliminate the cost of gangue mountain management, and eliminate the cost of land acquisition for the gangue mountain; secondly, to eliminate the problem of ground subsidence and collapse, and eliminate the compensation cost; thirdly, to reduce the outburst of water from the roof and floor plates and reduce the drainage cost; fourthly, to reduce gas outburst and ensure safe production; fifthly, to ensure the effect of retaining the two lanes, reduce or eliminate the movement of the roof and floor plates, eliminate the collapse of the roof of the goaf, and reduce the cost of retaining the lane.

[0004] In order to achieve these goals, the filling quality must be the same as or similar to the original coal seam support for the roof, and then the total amount of these reduced and cancelled costs can be used to offset the goaf filling costs, resulting in more benefits than disadvantages. Only in this way can the goaf gangue filling be successful.

[0005] At present, there are many methods for filling coal gangue in goafs, and various places are adopting and applying them according to their specific conditions and characteristics. For example, there are filling methods such as pumping paste filling method, mechanical conveying of primary gangue filling method, pumping plastic flow thick material filling method and rock filling method in goafs. However, these methods have a common feature, that is, the compaction coefficient and compaction space of the material after filling are large. Therefore, the economic value brought by the filling is not great. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a method for combining all-round solid filling of coal gangue in goaf with dense, roof-connected, gridded and supportive filling with safe production and economic benefits, so as to integrate investment and benefits and coexist interdependently, achieve the best effect of both worlds, realize the virtuous cycle of replacing coal with gangue, advanced support of goaf, and replacing the original coal seam support for the roof with coal gangue.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted is as follows:

[0008] A method for supporting solid filling of coal gangue in goaf is provided, which makes full use of the abandoned coal gangue to carry out compaction, top connection, gridding and supporting solid jet filling of the goaf, so as to realize all-round solid filling of coal gangue in the goaf.

[0009] Among them, during the filling process, high-strength coal gangue concrete filling materials and pure gangue non-strength filling materials are allocated through the control system, and the two materials are cross-sprayed. The goaf forms a mesh structure that combines a high-strength grid support system with a non-strength grid internal filling, forming a grid-like compressive structural support system, completing the goaf's dense, top-connected, gridded, and supportive all-round solid filling.

[0010] The grid-like compression-resistant structural support system includes a support grid composed of criss-crossed high-strength dense top continuous supporting filling solid walls and a pure coal gangue non-strength dense top adsorption filling entity in the inner surrounding area of ​​the support grid, and the high-strength dense top continuous supporting filling solid wall includes a transverse high-strength dense top supporting solid wall and a longitudinal high-strength dense top continuous supporting filling solid wall;

[0011] The high-strength gangue concrete filling material is a dry-hard gangue concrete filling material formed by mixing gangue powder with a mixed slurry of materials A and B; the material A is a blending agent, and the material B is a solidifying agent.

[0012] The pure gangue strength-free filling material is a dry and hard gangue mud filling material formed by mixing coal gangue powder with water.

[0013] The water content of the pure gangue non-strength filling material is 13% to 17%.

[0014] Among them, the ratio of the material A to the material B is 1:1; the ratio of the mixed slurry of the materials A and B to the coal gangue powder is 1:10.

[0015] Among them, the cross-spraying operation mode of the two materials adopts the operation method of moving the rack and filling.

[0016] Among them, the operation method of moving the frame and filling is that any hydraulic support moves forward, and the goaf behind the hydraulic support is quickly filled, and the hydraulic support moves forward and fills the back simultaneously.

[0017] The specific operating procedures include the following:

[0018] 1. Crushing of coal gangue

[0019] Since there is no suitable equipment to completely separate coal and gangue underground, it needs further development before it can be realized. Therefore, the gangue still needs to be transported from underground to the ground, and then from the ground to underground in a secondary transportation process.

[0020] On the ground, the gangue screened by the dynamic screening workshop and the gangue washed by the coal preparation workshop are transported to the gangue aggregate bin (or aggregate pile) by belt conveyors, and then crushed by crushers. The gangue after crushing is required to be a mixture of particles with a particle size of less than 2mm and powder (no grading requirements), and then transported to the coal gangue powder bin (or wellhead feeding bin) by belt conveyors and kept as dry as possible.

[0021] 2. Transportation of coal gangue powder and other materials from the ground to the underground working face:

[0022] 1. Transportation of coal gangue powder:

[0023] There are many ways to transport gangue powder from the ground gangue powder silo to the underground working face: using spiral pipe conveyor multi-section linking conveyor, belt conveyor conveyor, belt conveyor and spiral pipe conveyor relay conveyor, closed hanging scraper conveyor, etc. The selection can be determined according to the actual transportation environment conditions on site.

[0024] 2. Transportation of other materials:

[0025] Other materials refer to raw materials that can be mixed with coal gangue powder to form high-strength coal gangue concrete support materials. The raw materials are divided into two types: A material and B material. A material is a blending agent, a liquid material; B material is a coagulant, a dry powder material.

[0026] Material A can be transported from the ground storage tank to the underground working surface using a universal water pipe.

[0027] Material B can be transported by a series of mine cars.

[0028] The preparation method of the pure gangue non-strength filling material is as follows: after the gangue powder transported from the ground to the underground working face is fed into the feeding port of the filling wet spraying machine, the gangue powder is transported to the spray gun mouth of the filling wet spraying machine through the spraying pipe under the action of the main engine wind power, a water injection port is installed at the spray gun mouth, and the gangue powder is mixed with water in proportion at the spray gun mouth, wherein, after the gangue powder is mixed with water, the moisture content of the gangue powder is in the best state of 13% to 18%, which can reduce or eliminate the dust during spraying, forming dry and hard gangue mud with adsorption force, and then the dry and hard gangue mud with a certain impact force sprayed from the spray gun mouth is sprayed and accumulated into the goaf, forming a non-strength solid filling body that can connect to the top and has high density.

[0029] The preparation method of the high-strength coal gangue concrete filling material is as follows: material A and material B are mixed evenly in proportion by a mixing barrel of a grouting pump to form a slurry material. The slurry material is injected into the grouting port of a filling wet spraying machine spray gun through a grouting pipe, so that the slurry material and coal gangue powder are mixed in proportion at the filling wet spraying machine spray gun port to form dry hard coal gangue concrete, and then the dry hard coal gangue concrete with a certain impact ejected from the filling wet spraying machine spray gun port is sprayed and accumulated in the goaf to form a high-strength supporting solid filling body.

[0030] The high-strength coal gangue concrete filling material has the basic properties of ordinary concrete. 30 The concrete ratio is 1:10, weight ratio, 24h compressive strength is 11.6Mpa, 72h compressive strength is 23.8Mpa, 7 days compressive strength is 28Mpa, 28 days compressive strength is 30.3Mpa, and higher compressive strength standards can be achieved if required, and the cost is low and the transportation is convenient. Therefore, this type of coal gangue concrete material filling is called supporting filling.

[0031] The grid-based solid filling is as follows: in the process of filling goaf with coal gangue, grid-based filling is adopted in a large area of ​​goaf, and high-strength supporting filling materials are used to divide it into a grid-like main support system of vertical and horizontal cross walls, and then fill the grid with non-strength filling materials as an auxiliary support system. The grid-like structural support state of the goaf combined with the two realizes the replacement of coal with gangue at the lowest cost and the best support effect, and realizes the filling method of using coal gangue to replace the original coal seam to support the roof.

[0032] Through this all-round dense, top-connected, gridded, and supportive jet filling method, the cavities and gaps in the goaf are eliminated, the compaction space is reduced, the filling of the goaf is solidified, and the air flow in the goaf is effectively blocked. The adverse factors such as gas outburst, top and bottom plate movement, and water outburst are prevented, thereby fully maximizing the economic value brought by the filling.

[0033] Beneficial effects of the present invention:

[0034] 1. The waste rock heap can be eliminated. The air pollution caused by the spontaneous combustion of the waste rock heap can be eliminated, the vegetation damage can be eliminated, and the waste rock heap management costs and the waste rock heap land acquisition costs can be saved. Green mountains and clear waters can be returned to nature and the surrounding environment of the enterprise can be beautified.

[0035] 2. The coal gangue in the goaf is physically filled to replace coal with gangue, which can reduce or eliminate the problems of ground subsidence and collapse, minimize the damage to land and buildings, and eliminate compensation costs.

[0036] 3. Carry out compaction, roof connection, gridding, and supportive solid filling of the goaf to reduce or eliminate the damage to the roof and floor plates, reduce the outflow of water from the roof and floor plates, reduce the threat of water flooding on the mining working face, improve mining efficiency, and reduce drainage costs.

[0037] 4. Carry out compaction, top connection, gridding, and supportive solid filling in the goaf, and cover the goaf with dense filling in all directions to reduce gas outburst and ensure fast and safe recovery.

[0038] 5. The goaf is compacted, top-connected, gridded, and supported in a solid manner to achieve all-round support for the goaf. This can ensure the effect of retaining two lanes and reduce the cost of retaining lanes, thereby achieving pillar-free mining, improving the recovery rate of coal resources, reducing the amount of tunnel excavation, and alleviating the tension in mining and excavation continuity.

[0039] 6. The goaf is compacted, top-connected, gridded, and supported in a solid manner. A complete roof can be formed after mining, which greatly reduces or eliminates the amount of movement of the top and bottom plates in the goaf, reduces the pressure on the top and bottom plates, and creates good conditions for the next layer mining.

[0040] 7. All-round compaction, top connection, gridding, and support-based solid filling of the goaf can create good enclosed conditions for the goaf, effectively prevent air circulation in the goaf, eliminate the spontaneous combustion of coal gangue and coal residue, and eliminate the yellow mud grouting process in the goaf, saving loess resources and eliminating related purchase costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 It is a schematic diagram of the grid-like compression-resistant structural support system architecture of the present invention;

[0043] Figure 2 It is a structural schematic diagram of the spray gun 3 of the present invention;

[0044] Figure 3 It is a schematic diagram of the connection between the spray gun 3 and the hydraulic support 4 of the present invention. DETAILED DESCRIPTION

[0045] The present invention mainly describes a new filling method which adopts high-strength coal gangue concrete filling material and non-strength filling material to form a new filling process of all-round dense, top-connected, gridded and supportive filling process in underground goaf, which changes the previous coal mining method of all-caving method, improves the roof support of the mining working face, and realizes a higher level of safe production.

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0048] This process is explained by taking the example of mining the full-height working surface at one time.

[0049] 1. Ground part:

[0050] Build a gangue aggregate bin near the ground wellhead, a gangue crushing workshop, a gangue powder bin, an A material solution storage tank (insulation measures are required, the storage temperature in winter should not be lower than 6°C), and a B material storage warehouse.

[0051] Equipment: Gangue crusher and supporting dust removal equipment, belt conveyor for use.

[0052] (1) Preparation of coal gangue powder: The gangue screened by the dynamic screening workshop and the gangue washed by the coal preparation workshop are transported to the gangue aggregate bin for buffering by belt conveyors, and then transported to the coal gangue crushing workshop by belt conveyors. After being crushed by the crusher, the coal gangue powder is transported to the coal gangue powder bin by belt conveyors for standby use.

[0053] (2) Pump the prepared material A solution into the solution storage tank for standby use.

[0054] (3) Transport the prepared B material to the B material storage warehouse for standby use.

[0055] At this point, the production and preparation of materials are completed.

[0056] 2. Material transportation from the ground to the underground working surface:

[0057] (1) Transportation of coal gangue powder: It should be determined on site according to different environmental conditions. It can be transported in series by spiral pipe conveyor, belt conveyor, or suspended fully enclosed scraper. In short, no matter which transportation method is adopted, the coal gangue powder can be transported to the feed port of the underground working face filling wet spraying machine according to the required amount under the premise of minimum investment, thus completing the transportation of coal gangue powder.

[0058] (2) Transportation of Material A: Material A is a liquid material. A universal water pipe is installed from the ground to the underground working surface as a dedicated transportation pipeline for Material A.

[0059] (3) Transportation of Material B: Material B is a bagged dry powder and can be transported by a series of mine cars.

[0060] At this point, the work of transporting materials from the ground to the underground working face has been completed.

[0061] 3. Goaf filling equipment and installation layout of working face:

[0062] The goaf filling equipment can be mining filling wet spraying machine and mining pneumatic grouting pump.

[0063] Equipment installation and layout: Arrange the mining filling wet shotcrete machine and mining pneumatic grouting pump at the intersection or nearby points of the working face material lane and cutting lane.

[0064] (1) Arrangement of the grouting pipe of the mine filling wet shotcrete machine:

[0065] The total length of the grouting pipeline of the mine-filled wet shotcrete machine is from the outlet of the filling wet shotcrete machine main engine, across the tail of the hydraulic support of the working face, and all the way to the last hydraulic support. When the pipeline crosses the hydraulic support, it starts from the first hydraulic support and ends at the last hydraulic support. A three-way pipe fitting is installed in the middle of each hydraulic support. Then, a wet shotcrete spray gun for spraying filling materials into the goaf is installed in the middle of each hydraulic support, that is, a plurality of spray guns 3 are installed in a grouting pipeline, and one end of the tail of the spray gun 3 is connected to the three-way pipe fitting with a spray hose, and one end of the head of the spray gun 3 is a spray gun port 6. A valve is installed at the connection between the tail of the spray gun 3 and the spray hose to control the spraying and shutting down of the coal gangue powder. At this point, the grouting pipeline of the mine-filled wet shotcrete machine is arranged.

[0066] (2) Arrangement of the grouting pipeline of the pneumatic grouting pump for mining:

[0067] First, the structure of the spray gun 3 is described. Figure 2 As shown, the spray gun 3 is a tapered steel pipe about 500 mm long, and the thick end is connected to the wet spraying machine grouting pipe, which is called the feed port. The narrow end is the discharge port, which is called the spray gun port 6. On the pipe wall of the tapered steel pipe 8 at the thick end of the spray gun 3, two short pipe interfaces are symmetrically installed, one of which is the water injection port 5 of the spray gun 3, and the other is the grouting port 7 of the spray gun 3. A valve is installed at the water injection port 5 and the grouting port 7 of the spray gun 3 respectively to control their flow rates. Then, when using a non-strength filling material, the water injection valve is opened (the grouting valve is closed) to form a mixture of coal gangue powder and water; when using a high-strength coal gangue concrete filling material, the grouting valve is opened (the water injection valve is closed).

[0068] The arrangement of the grouting pipe of the pneumatic grouting pump for mining is the same as that of the grouting pipe of the filling wet spraying machine for mining, except that the grouting pipe led out of the tee of the grouting pipe of the pneumatic grouting pump is connected to the grouting port valve on the spray gun of the wet spraying machine. The arrangement of the water pipe is the same, just connect the grouting pipe led out of the tee to the water injection port valve on the spray gun of the wet spraying machine.

[0069] (3) Fixed connection between hydraulic support 4 and spray gun 3:

[0070] First, the grouting pipelines and water pipes of the mine filling wet shotcrete machine and the mine pneumatic grouting pump are all across the tail of the hydraulic support of the working face and are arranged all the way to the last hydraulic support. The hydraulic support is moved forward separately. Therefore, in order to prevent the hydraulic support from affecting the grouting pipelines that cross horizontally when moving forward, Figure 3 As shown, a circular chain 401 is installed under the tail beam of the hydraulic support 4, and the pipeline connected to the spray gun 3 is hung on the circular chain 401 under the tail beam, so that a soft transition is formed between the pipeline and the hydraulic support 4 to ensure that the pipeline is not squeezed and leaked.

[0071] Secondly, in order to make the injection filling operation safer, a safety baffle 403 is installed at the tail of the hydraulic support 4 base to play a safety protection role at any time. The safety baffle 403 can be fixed on the oil cylinder 402 of the hydraulic support 4 base.

[0072] Third, during the filling process, if manual operation is adopted, the spray gun needs to be hung under the tail beam, and the spray gun nozzle needs to be manually operated to swing upward, downward, left, and right to spray. If a remote control system is adopted, a control cylinder and control system need to be added to the tail of the hydraulic support to control the spray gun nozzle to swing upward, downward, left, and right to spray. At this point, the installation and arrangement of all equipment is complete.

[0073] The arrangement of the hydraulic support and the spray gun 3 of the present invention is not limited to the above Figure 3 As long as it meets the requirements of the present invention and can realize the operation method of moving the frame and filling, that is, any hydraulic support moves forward, the goaf behind the hydraulic support is quickly filled, and the method of moving the hydraulic support forward and filling the rear simultaneously can be fixed, and the present invention does not make specific limitations.

[0074] 4. Specific injection filling implementation method:

[0075] (1) Specific injection filling operation implementation method:

[0076] First, check that the shotcrete pipelines used for filling operations are unobstructed, the water supply from the water pipes is normal, the valves are flexible in operation, the mine filling wet shotcrete machines and mine pneumatic grouting pumps are working properly, and the filling materials are transported to the site.

[0077] Second, before filling the goaf, extend the side guard plates of the end frame hydraulic support in time to ensure that a separation wall is built between the top control area of ​​the hydraulic support of the working face and the area to be filled (including the retained lane).

[0078] Third, for filling operation, the method of filling must be adopted when the frame is moved. That is, no matter which hydraulic support is moved forward, it will start to be filled quickly.

[0079] Fourth, after the filling operation is completed (after the shift is over), clean the mining pneumatic grouting pump and the attached grouting pipes and valves in time to prevent the A and B slurries from solidifying (the slurries should not stay in the grouting pump for more than 3 hours) and damaging the equipment. Cleaning method: add tap water to the mixing barrel of the grouting pump for stirring and cleaning, and at the same time turn on the wet spraying machine and the grouting pump to continue spraying the filling material. When the material sprayed out by the spray gun becomes a filling material with no strength, the grouting pump is considered to have been cleaned. At this time, the equipment can be shut down, the pipeline valves can be closed, the power supply can be cut off, and the filling work of the shift can be ended.

[0080] Fifth, the operation of the filling equipment: (taking manual operation as an example), such as Figure 2 , 3 As shown,

[0081] a. Operation method of filling with high-strength coal gangue concrete material: First, feed material A and material B into the mixing barrel of the pneumatic grouting pump in a ratio of 1:1 and mix them evenly; feed the coal gangue powder into the feeding port of the filling wet spraying machine; then, open the grouting pipe valve of the wet spraying machine under the hydraulic support that has been moved first, open the grouting pipe valve at the spray gun port, start the equipment and start the spraying filling operation. Under the action of the filling wet spraying machine, the coal gangue powder is injected into the spray gun port 6 through the pipeline 8; at the same time, under the action of the pneumatic grouting pump, the mixed slurry A and B in the grouting pipe of the grouting pump is injected into the spray gun of the wet spraying machine through the grouting port 7. At the outlet of the spray gun, the gangue powder is fully mixed with the A and B mixed slurries. Under a certain wind force, the mixed material is sprayed away from the spray gun mouth 6 to form a dry, hard, high-strength gangue concrete spraying filling material. Under the manual control of the spray gun to swing upward, downward, left and right, the filling material is evenly sprayed into the goaf for accumulation, and sprayed layer by layer from bottom to top and from far to near to form a dense, top-connected, supportive filling body.

[0082] After the space behind the hydraulic support that has been moved first is filled, the wet spraying machine and the grouting pump are shut down in time, and the valve is closed. Then, the goaf area behind the next hydraulic support is sprayed and filled, and the operation is carried out in sequence until all the hydraulic supports have been moved forward, and a high-strength, dense, top-connected, continuous supporting filling solid wall 1 is formed in the goaf area behind the support. For example, if the length of a mine working face is 240m, the mining height is 2.8m, and the cutting depth is 0.6m, then, each time each hydraulic support moves forward, there will be a goaf area of ​​0.6m (cutting depth) × 1.5m (frame width) × 2.8m (mining height) behind the support that can be sprayed and filled. When all 160 hydraulic supports have been moved forward, a dense top-connected supporting solid wall with a length of 240m × a width of 0.6m × a height of 2.8m with a C30 concrete compressive strength will be formed in the goaf area behind the support.

[0083] b. Operation method of using pure coal gangue powder for filling: When a high-strength dense top-connected continuous support filling solid wall 1 is filled, when the hydraulic support moves forward next time, pure coal gangue powder non-strength filling material can be used for goaf filling operation.

[0084] The operation method is as follows: first, feed the gangue powder into the feeding port of the wet spraying machine, inject tap water into the mixing barrel of the grouting pump, then open the grouting pipe valve of the wet spraying machine under the hydraulic support of the first moving frame, open the water injection pipe valve at the spray gun mouth, start the equipment, and start the spraying and filling operation. Under the action of the filling wet spraying machine, the gangue powder is injected into the spray gun mouth 6 through the pipeline 8; at the same time, under the action of the pneumatic grouting pump, the water in the grouting pipe of the grouting pump is injected into the wet spraying machine spray gun through the water injection port 5. At the outlet of the spray gun mouth 6, the gangue powder and water are fully mixed. Under the action of a certain wind force, the mixed material is sprayed out of the spray gun mouth to form a dry and hard gangue mud filling material with no strength. Under the manual control of the spray gun to swing upward, downward, left and right, the filling material is evenly sprayed in the goaf for accumulation, and sprayed layer by layer from bottom to top and from far to near to form a dense, top-connected, adsorbent filling body. After the space behind the frame is filled, the wet spraying machine and grouting pump are shut down in time, and the valve is closed. Then, the goaf area behind the next hydraulic support is sprayed and filled, and the cycle is repeated. Finally, when all hydraulic supports are moved forward, a pure coal gangue non-strength dense top adsorption filling entity 2 is formed in the goaf area behind the frame.

[0085] The operation method of the grid filling operation described in the present invention is specifically described as follows:

[0086] When performing jet filling operations in goaf areas, the method of filling the goaf areas after each hydraulic support is moved forward with supporting materials in a grid pattern is called grid filling, forming a grid-shaped compressive structural support system. Figure 1As shown, the grid-like compression-resistant structural support system includes a support grid composed of a criss-cross high-strength dense top-connected continuous supporting filling solid wall 1 and a pure coal gangue non-strength dense top-connected adsorbent filling entity 2 in the inner surrounding area of ​​the support grid. The high-strength dense top-connected continuous supporting filling solid wall 1 includes a transverse high-strength dense top-connected supporting solid wall 101 and a longitudinal high-strength dense top-connected continuous supporting filling solid wall 102.

[0087] For example: when spraying a horizontal high-strength dense top-connected continuous support filling solid wall, the goaf behind the horizontal hydraulic support of the same depth can be sprayed and filled with high-strength coal gangue concrete materials. The spraying of the next support filling solid wall can be determined by the cumulative forward movement distance of the hydraulic support. For example: the previous and next support filling solid walls are to be separated by 6m, so the frame is moved 0.6m at a time, and the operation can be repeated when the frame is moved ten times in total. During the ten hydraulic support frame shifting processes in the middle interval, pure coal gangue powder non-strength filling materials can be sprayed in the goaf behind the frame. When spraying a vertical high-strength dense top-connected continuous support filling solid wall, high-strength coal gangue concrete materials can be fixedly sprayed and filled in several horizontally arranged hydraulic supports according to the interval requirements. For example, when the high-strength coal gangue concrete material is fixed on the first, sixth, and eleventh frames, the spacing of the vertical high-strength dense top-connected continuous support filling solid wall is 6m, then the goaf after the second, third, fourth, and fifth hydraulic supports move forward can be sprayed with pure coal gangue powder non-strength filling material. Cycle in sequence, thus forming a square grid support system with a vertical and horizontal spacing of 6m, and at the same time, the square grid is sprayed with non-strength filling materials. At this point, a new method of filling the goaf has been formed---dense, top-connected, grid-based, supportive solid filling method.

[0088] The shape of the support grid formed by the high-strength, dense, top-connected, continuous supporting filling solid wall 1 in the grid-like compression-resistant structural support system of the present invention is not limited to Figure 1 The square or rectangle may be any other shape that meets the scope of mechanical support, such as rhombus, circle, polygon, etc. In addition, the injection process of the present invention can be controlled by human or system to switch the injection valve, which belongs to the scope of the prior art and is not specifically limited in the present invention.

[0089] Initial filling method:

[0090] During the initial filling stage, first of all, the original empty spaces in the goaf and the areas that the wet spraying machine can reach should be sprayed with all-round dense top-connected continuous support filling entities until all the original empty spaces in the goaf are filled and connected to the top, and then the goaf is moved again to spray the entire length of the goaf with dense top-connected continuous support filling entity wall. At this stage, a buffer stage is formed from the natural collapse of the goaf roof to no collapse. With the forward movement of the hydraulic support, the roof still sinks to a certain extent. When the grid support entity filling reaches a certain effective length of support, a stable and dense filling support system will be formed, and a stable roof can be formed, and then the dense, top-connected, grid-based, and support entity filling under normal conditions will be entered. At this point, the initial filling work of the goaf is completed.

[0091] The filling method of the present invention is compared with the existing filling method. The filling material cost is shown in Table 1 below:

[0092] Filling method Filling material fee Direct material cost of paste filling <![CDATA[79.7 yuan / m 3 > Loose primary gangue filling material fee <![CDATA[26.9 yuan / m 3 > Filling method of the present invention <![CDATA[23.5 yuan / m 3 >

[0093] Since the filling method of the present invention can fully utilize the coal gangue generated in the coal mining process, there is still a shortage of a certain amount of coal gangue filling materials on the basis of complete utilization of the coal gangue generated by the coal mine itself.

[0094] Taking a mine with an annual output of 1.5 million tons as an example, the working face is 240m long and the mining height is 2.8m. The annual raw coal output is 1.5 million tons, clean coal is 900,000 tons, and gangue is 600,000 tons. The calculated gangue content is 40%. The remaining 60% of the gangue needs to be supplemented by collecting external gangue, which can be achieved with paid charging. Calculated at a charging fee of 20 yuan / ton, the charging fee can reach 18 million yuan, thus bringing huge economic benefits to the production enterprise.

[0095] The filling process of the present invention is simple and effective, does not occupy coal mining time, and can be filled as coal is mined. The filling process can be manually controlled on site or by remote automatic control for jet filling. It has high safety. During the filling process, no personnel are required to enter the filling area. The filling cost is greatly reduced.

Claims

1. A method for supporting solid filling of coal gangue in goaf, characterized by: Make full use of abandoned coal gangue to carry out compaction, roof connection, gridding, and support solid injection filling in the goaf, so as to realize the all-round solid filling of coal gangue in the goaf; During the filling process, high-strength coal gangue concrete filling materials and pure gangue non-strength filling materials are deployed through the control system, and the two materials are cross-sprayed to form a mesh structure state combining a high-strength grid support system with non-strength grid internal filling in the goaf, forming a grid-like compressive structural support system, and completing the all-round solid filling of the goaf with dense, top-connected, grid-like, and supportive properties; The cross-spraying operation of the two materials adopts the operation method of moving the rack and filling; The operation method of the frame moving and filling is that any hydraulic support moves forward, and the goaf behind the hydraulic support is quickly filled, and the hydraulic support moves forward and the back filling is carried out synchronously; The high-strength coal gangue concrete filling material is a dry and hard coal gangue concrete filling material formed by mixing coal gangue powder with a mixed slurry of materials A and B; the material A is a blending agent, and the material B is a coagulant; The pure gangue non-strength filling material is a dry and hard gangue mud filling material formed by mixing coal gangue powder with water; A wet spray gun for spraying filling materials into the goaf is installed in the middle of each hydraulic support, and multiple spray guns are installed on one spray pipe; the thick end of the spray gun is connected to the wet spray pipe, and the narrow end is the spray gun port. Two short pipe interfaces are symmetrically installed on the pipe wall of the tapered steel pipe at the thick end of the spray gun, one of which is the water injection port of the spray gun, and the other is the grouting port of the spray gun. A valve is installed at the water injection port and the grouting port of the spray gun to control the flow rate; The operation method of filling with high-strength coal gangue concrete filling material is as follows: first, feed material A and material B into the mixing barrel of the pneumatic grouting pump in a ratio of 1:1 and mix them evenly; feed the coal gangue powder into the feeding port of the wet spraying machine; then, open the valve of the wet spraying machine grouting pipe under the hydraulic support of the advance frame, open the valve at the grouting port at the spray gun port, start the equipment to start the spraying and filling operation; under the action of the wet spraying machine, the coal gangue powder is injected into the spray gun port through the tapered steel pipe; at the same time, under the action of the pneumatic grouting pump, the A and B mixed slurries in the grouting pipe of the grouting pump are injected into the wet spraying machine spray gun through the grouting port; at the spray gun outlet, the coal gangue powder is fully mixed with the A and B mixed slurries, and under the action of wind, the mixed material is sprayed out of the spray gun port to form high-strength coal gangue concrete filling material; Use pure gangue non-strength filling material to fill the goaf; first, feed the gangue powder into the feeding port of the wet spraying machine, inject tap water into the mixing barrel of the grouting pump, then, open the valve of the wet spraying machine grouting pipe under the hydraulic support of the first moving frame, open the valve at the water injection port at the spray gun mouth, start the equipment, and start the spraying filling operation; under the action of the wet spraying machine, the gangue powder is injected into the spray gun mouth through the tapered steel pipe; at the same time, under the action of the pneumatic grouting pump, the water in the grouting pipe of the grouting pump is injected into the wet spraying machine spray gun through the water injection port; at the outlet of the spray gun mouth, the gangue powder and water are fully mixed, and under a certain wind force, the mixed material is sprayed out of the spray gun mouth to form a pure gangue non-strength filling material; The water content of the pure gangue non-strength filling material is 13% to 17%.

2. A method for supporting solid filling of coal gangue in goaf according to claim 1, characterized in that: The grid-like compression-resistant structural support system includes a support grid composed of criss-crossed high-strength dense top-connected continuous supporting filling solid walls and a pure coal gangue non-strength dense top-connected adsorbent filling entity in the inner surrounding area of ​​the support grid. The high-strength dense top-connected continuous supporting filling solid wall includes a transverse high-strength dense top-connected supporting solid wall and a longitudinal high-strength dense top-connected continuous supporting filling solid wall.

3. The method for supporting solid filling of coal gangue in goaf according to claim 1, characterized in that: The ratio of the material A to the material B is 1:1; the ratio of the mixed slurry of the materials A and B to the coal gangue powder is 1:10.

Images