Novel forward comprehensive mechanized mining method for dense filling

Abstract

The invention relates to the technical field of coal mining, and discloses a compact filling novel advancing type comprehensive mechanized mining method which comprises the following steps: pre-digging cutting holes along upper and lower mountain coal pillars of a mining area to form a production system of an advancing type working face; the coal mining machine, the scraper conveyor and the reversed loader are linked to stope the solid coal; an inorganic non-combustible paste material is continuously injected into the mined-out area after stoping through a pipeline, the whole section is densely filled, and the uniaxial compressive strength of the paste material is larger than or equal to 3.5 MPa after the paste material is solidified for 28 days; according to the novel compact-filling advancing type comprehensive mechanical mining method, through full-section compact filling of the goaf and use of the inorganic non-combustible paste material, the air leakage rate can be reduced by 90% or above, and a residual coal oxidation zone is shortened to be within 5 m. Through closed-loop control of distributed optical fiber temperature measurement and laser displacement monitoring, the risks of high-temperature cracking and sudden weighting are eliminated.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a novel compacted backfilling method for forward-moving fully mechanized mining. Background Technology

[0002] Forward mining refers to a mining sequence in which the working face advances continuously from the boundary of the shaft or main roadway towards the boundary of the mining area, with the direction of advancement away from the main haulage (or auxiliary haulage) roadway. Traditional forward mining inherently has the following drawbacks:

[0003] Fire prevention and extinguishing are difficult: there are many air leakage channels in the goaf, the width of the oxidation zone of residual coal can reach 30-60m, the natural ignition period is shortened to 20-60 days, and the ignition rate remains high.

[0004] The ventilation system is complex: it requires the excavation of two or more tunnels in advance to form a "Z" or "Y" shaped ventilation network, with a large number of air doors and air walls, resulting in a large workload for daily maintenance.

[0005] The tunneling work involves a large amount of work: the tunneling rate of 10,000 tons is generally 35-60m, the tunneling team occupies more than 30% of the personnel, and the mining and tunneling continuity is tight.

[0006] High risk of surface subsidence: The subsidence coefficient caused by the collapse method of the roof slab is 0.6 to 0.9, and the probability of damage to buildings of level III or above is >40%.

[0007] Difficulties in equipment matching and roadway retention: Existing coal mining machines, scraper conveyors, transfer machines and other equipment do not consider the dual functions of "crossing roadway + retaining roadway", insufficient space at the machine head and lack of end support, resulting in poor roadway formation, frequent roof and side falls, and low operational safety. Summary of the Invention

[0008] To address the problems mentioned in the background art, the present invention provides the following technical solution: a novel advanced mechanized mining method with dense backfilling, comprising:

[0009] Pre-excavation of cutting holes along the coal pillars at the top and bottom of the mining area forms a production system with an advancing working face;

[0010] The coal mining machine, scraper conveyor, and transfer conveyor are used in tandem to mine solid coal.

[0011] After mining, the goaf is continuously injected with inorganic non-flammable paste material through pipelines and completely filled with it. The paste material has a uniaxial compressive strength of ≥3.5MPa after 28 days of solidification.

[0012] After the filling material solidifies, it forms a goaf-side roadway near the roadway, which serves as the mining roadway for the next working face.

[0013] At the equipment end, the coal mining machine is equipped with a rocker arm transition frame, the scraper conveyor head structure is modified, the transfer machine is equipped with a rear dragging device, and the end support is equipped with side wing guard plates to achieve synchronous equipment advancement and roadway support.

[0014] Furthermore, the goaf-side roadways on both sides of the filling body are respectively transportation roadways and material roadways, and the goaf-side roadways are connected to the main transportation roadway and / or return air roadway of the mining area.

[0015] Furthermore, the goaf-retaining area is reinforced with isolation formwork and unit supports, with a support length of not less than one month's mining distance.

[0016] Furthermore, the isolation frame and unit support are specifically as follows:

[0017] The isolation formwork consists of two rows of individual hydraulic supports, π-shaped steel beams, and flame-retardant ventilation duct fabric, with a row spacing of 1.0–1.2m;

[0018] The unit support is a tracked hydraulic support with an adjustable support height of 2.2–4.0m and an initial support force ≥2400kN / frame;

[0019] The combined support coverage of the isolation formwork and unit support is 30–50m behind the working face, and moves forward as the working face advances.

[0020] Furthermore, the inorganic non-combustible paste material is composed of fly ash, cement, gangue powder, water, and a composite early-strength agent, with the following part ratios: 35–45 parts fly ash, 8–12 parts cement, 25–35 parts gangue powder, 15–20 parts water, and 0.5–1.5 parts composite early-strength agent. The slump of the inorganic non-combustible paste material is maintained at 180–220 mm, the initial setting time is 3–5 h, and the final setting time is 6–8 h.

[0021] Furthermore, a rocker arm transition frame is added between the traction and traveling part of the coal mining machine and the cutting rocker arm.

[0022] Furthermore, the modified head structure of the scraper conveyor includes:

[0023] The scraper conveyor eliminates the sprocket box and motor base, and replaces them with an integral π-shaped crossbeam;

[0024] The center height of the unloading roller at the head of the scraper conveyor is lowered by 150–200 mm to increase the passage space for the transfer machine bridge.

[0025] The scraper conveyor is equipped with a tiltable maintenance platform on both sides of the head, with a platform width ≥600mm and a load capacity ≥2kN / m².

[0026] Furthermore, the transfer machine is equipped with a rear dragging device, including:

[0027] The rear universal hinged slip shoe of the transfer machine has a wear-resistant plate welded to the bottom surface of the slip shoe with a thickness of ≥12mm;

[0028] Multiple sliding cylinders are installed between the rear end of the slipper and the bottom plate of the transfer machine, with a stroke of 0.8-1.2m and a thrust ≥250kN;

[0029] Multiple sliding cylinders are arranged in combination to allow the tail end of the transfer machine to swing within a horizontal ±10° and a vertical ±5° range.

[0030] Furthermore, the side wing guard plate of the end support is a telescopic box-type structure with a telescopic stroke of 0.6-1.0m. The front end of the guard plate is hinged to an anti-scraping telescopic beam with an extension length of 0.4-0.6m, and a 5mm thick polymer anti-sticking coal lining plate is laid on its surface.

[0031] Furthermore, it also includes online monitoring and intelligent control, specifically:

[0032] A distributed optical fiber temperature measurement system is pre-buried in the goaf area, with optical fiber spacing of 2-3m, to monitor the internal temperature of the filling body in real time.

[0033] When the temperature at any measuring point is ≥45℃, the ground grouting station is automatically triggered to increase the moisture content of the paste by 3–5% and reduce the cement ratio.

[0034] When a laser displacement sensor is installed on the roof of the goaf-stayed roadway, and the roof subsidence exceeds 15mm, the support resistance of the unit support is automatically increased by 10–15%, and an audible and visual alarm signal is issued.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. This novel compacted backfilling method for advanced mechanized mining, through full-section compacted backfilling of the goaf and the use of inorganic non-combustible paste materials, can reduce air leakage by more than 90%, shorten the oxidation zone of residual coal to within 5m, and extend the ignition period to more than 180 days, achieving "zero spontaneous combustion." Closed-loop control using distributed fiber optic temperature measurement and laser displacement monitoring can stabilize the internal temperature of the backfill body at no more than 45℃ and the roof subsidence at less than 15mm, eliminating the risks of high-temperature cracking and sudden pressure surges.

[0037] 2. This new type of dense-filling forward-moving fully mechanized mining method only requires pre-excavation along the upper and lower coal pillars. The remaining roadways are formed by "coal mining machine cutting + paste filling". This can reduce the tunneling rate per 10,000 tons to below 15m and reduce the number of tunneling teams by about 55%. The time to form a forward-moving working face is reduced from the traditional 30-45 days to 7-10 days, and the tension of mining and tunneling continuity is significantly alleviated.

[0038] 3. This new type of dense-filling forward-moving fully mechanized mining method increases the distance from the unloading point at the head of the coal mining machine to the coal face from 0.8m to 2.0m by adding a rocker arm transition frame, enabling the "cutting through the head" to pass synchronously with the transfer conveyor and crusher. The height of the scraper conveyor head is reduced by 150-200mm, and a tiltable maintenance platform is installed, reducing the equipment failure rate by more than 40%. The rear dragging device of the transfer conveyor (universal hinged slipper and sliding cylinder) allows the tail end to swing horizontally ±10° and vertically ±5° to adapt to the undulation of the floor, reducing the relocation time from 2 hours to 20 minutes. The side wing guards of the end support + anti-sparing telescopic beam increase the lateral support strength of the roadway to 2400kN / frame, reducing the roof collapse accident rate by 95%.

[0039] 4. This new type of dense-filling forward-moving fully mechanized mining method features a "full negative pressure ventilation and dual safety exits" system at the working face. Compared to traditional local fan ventilation, the number of gas exceedances is reduced by 80%, and emergency escape capabilities are significantly improved. The roadway support adopts a combination of tracked walking unit supports and isolation formwork, increasing support relocation efficiency by 3 times and reducing labor costs by approximately 50%.

[0040] 5. This novel compacted filling forward-moving fully mechanized mining method establishes an intelligent control system of "temperature measurement, parameter adjustment, and alarm." The ground grouting station automatically adjusts the water-cement ratio by ±3% to 5% based on real-time data, reducing the backfill mass fluctuation coefficient from 12% to 3%. Laser displacement monitoring is linked to hydraulic supports to achieve adaptive adjustment of support resistance, maintaining a roof integrity rate of over 98% in the roadway, thus providing a stable channel for subsequent intelligent coal mining. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of the present invention;

[0042] Figure 2 This is a schematic diagram of the goaf retention structure of the present invention.

[0043] In the diagram: 1. Coal face; 2. Backfill; 3. Goaf roadway; 4. Transport roadway; 5. Return air roadway; 6. Cut-off point; 7. Unit support; 8. Isolation formwork; 9. Transfer conveyor. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] An example of this novel dense-filling forward-moving fully mechanized mining method is as follows:

[0046] Please see Figures 1-2 A novel compacted backfilling method for advanced mechanized mining includes:

[0047] A1. Pre-excavate cut-off holes 6 along the coal pillars of the mining area to form a forward working face production system; before the working face is put into production, only short-distance roadways are excavated in the return roadways, and the remaining return roadways are completed using an integrated mining and excavation construction process.

[0048] A2. The coal mining machine, scraper conveyor, and transfer machine 9 are used in a three-machine linkage to mine solid coal. Among them, the coal mining machine is equipped with a rocker arm transition frame, the scraper conveyor head structure is modified, the transfer machine 9 is equipped with a rear dragging device, and the end support is equipped with side wing guard plates to achieve synchronous equipment advancement and roadway support.

[0049] It should be noted that a rocker arm transition frame is added between the traction and traveling part of the coal mining machine and the cutting rocker arm.

[0050] The modified head structure of the scraper conveyor includes: the scraper conveyor eliminates the sprocket box and motor base, and replaces them with an integral π-shaped crossbeam; the center height of the unloading roller of the scraper conveyor head is reduced by 150–200 mm to increase the passage space of the transfer machine 9; and a tiltable maintenance platform is set on both sides of the scraper conveyor head, with a platform width ≥ 600 mm and a load-bearing capacity ≥ 2 kN / m².

[0051] The transfer machine 9 is equipped with a rear dragging device, which includes: a universal hinged slip shoe at the tail of the transfer machine 9, with a wear-resistant plate welded to the bottom surface of the slip shoe, the thickness of which is ≥12mm; multiple sliding cylinders are installed between the rear end of the slip shoe and the bottom plate of the transfer machine 9, with a stroke of 0.8-1.2m and a thrust of ≥250kN; the multiple sliding cylinders are combined and distributed so that the tail end of the transfer machine 9 can swing within a horizontal ±10° and a vertical ±5° range.

[0052] The side wing guard plate of the end support is a telescopic box-type structure with a telescopic stroke of 0.6-1.0m. The front end of the guard plate is hinged to an anti-scraping telescopic beam with an extension length of 0.4-0.6m, and a 5mm thick polymer anti-sticking coal lining plate is laid on its surface.

[0053] A3. After mining, inorganic non-flammable paste material is continuously injected into the goaf through pipeline and densely filled across the entire cross-section to form filling body 2. The paste material has a uniaxial compressive strength ≥3.5MPa after 28 days of solidification.

[0054] It should be noted that the inorganic non-combustible paste material is composed of fly ash, cement, gangue powder, water, and composite early-strength agent, with the following part ratio: 35-45 parts fly ash, 8-12 parts cement, 25-35 parts gangue powder, 15-20 parts water, and 0.5-1.5 parts composite early-strength agent. The slump of the inorganic non-combustible paste material is maintained at 180-220 mm, the initial setting time is 3-5 h, and the final setting time is 6-8 h.

[0055] A4. After the filling material 2 solidifies, a gob-side retainer 3 is formed on the side near the roadway, which serves as the return roadway for the next working face. The gob-side retainers 3 on both sides of the filling material 2 are the transport roadway and the material roadway, respectively. The gob-side retainers 3 are connected to the main transport roadway 4 and / or the return air roadway 5 of the mining area.

[0056] It should be noted that the area along the goaf retaining roadway 3 is reinforced with isolation formwork 8 and unit supports 7, with a support length of not less than one month's mining distance. Specifically, the isolation formwork 8 and unit supports 7 are as follows: the isolation formwork 8 consists of two rows of single hydraulic props, π-shaped steel beams, and flame-retardant ventilation ducts, with a row spacing of 1.0–1.2m; the unit supports 7 are tracked hydraulic supports with an adjustable support height of 2.2–4.0m and an initial support force ≥2400kN / frame; the combined support coverage of the isolation formwork 8 and unit supports 7 is 30–50m behind the working face, moving forward as the working face advances.

[0057] In addition, it also includes online monitoring and intelligent control, specifically:

[0058] A distributed optical fiber temperature measurement system is pre-embedded in the goaf area, with an optical fiber spacing of 2–3m, to monitor the internal temperature of the filling body 2 in real time. When the temperature at any measuring point is ≥45℃, the ground grouting station is automatically triggered to increase the moisture content of the paste by 3–5% and reduce the cement ratio. A laser displacement sensor is installed on the roof of the goaf-retaining roadway 3. When the roof subsidence is >15mm, the support resistance of the unit support 7 is automatically increased by 10–15%, and an audible and visual alarm signal is issued.

[0059] Detailed Explanation of the New Type of Advanced Mechanized Mining Method with Dense Filling:

[0060] Coal mining and goaf backfilling adopt a fully mechanized paste filling coal mining process. Before the working face is put into production, only a short distance of the mining roadway is excavated. The remaining mining roadway is completed using an integrated mining and excavation construction process. The coal body is cut by a coal mining machine, and the two ends of the working face are parallel supported. A dense inorganic non-combustible paste material is used for filling to achieve safe roadway retention along the goaf. The cutting face is arranged along the direction of the mining area roadway. During the initial mining of the working face, the cutting face is arranged in an advancing production working face adjacent to the mining area roadway.

[0061] Before production begins at the working face, only a small portion of the mining roadways are excavated; most of the mining roadways do not require excavation. The area ahead of the working face is the coal face 1. By optimizing the coal mining process and equipment such as the coal mining machine, scraper conveyor, and transfer conveyor 9, the equipment's ability to cut and recover coal resources across roadways is improved, reducing the amount of excavation work. The goaf area of ​​the working face is densely filled with inorganic non-combustible paste material, effectively reducing the risk of fire within the goaf. By optimizing the compressive strength of the filling material 2, the overall integrity of the filling material 2 is improved. The 28-day solidification strength of the filling material 2 exceeds 3.5 MPa, allowing a goaf-side roadway 3 to form on one side of the filling material 2.

[0062] This technology can save on the amount of tunneling work in the coal mining face roadway, and significantly shorten the time for the coal mining face to form a ventilation system, which is beneficial to the continuity of mine production. By using the coal mining machine to cut and fill the roadway, compared with the roadway construction by the tunneling machine, the coal mining filling roadway adopts full negative pressure ventilation, which is more reliable than the traditional tunneling that relies on local fans for air supply. At the same time, it has two safety exits, which improves the emergency escape capability compared with the traditional tunneling.

[0063] In the working face, dense backfill paste is used to manage the goaf roof. Only short-distance roadways are excavated in the recovery roadways, creating a fully negative-pressure ventilation system at the working face to meet production requirements such as coal transport and to accommodate equipment installation. The recovery roadways are formed by cutting and backfilling with a coal mining machine. The main recovery roadways are cut by the coal mining machine and backfilled on one side of the recovery roadway and the goaf, forming a roadway retention process along the goaf side. This process requires less investment in tunneling and results in lower mining costs. The coal mining machine cuts out two roadways of the designed width, reducing the support workload on one side of the roadway. This increases construction efficiency by 33% compared to pre-excavated roadways, reduces the investment in tunneling equipment and support materials, and lowers mining costs.

[0064] The forward-advancing mining method involves advancing the working face in a direction opposite to the mining area, either uphill or downhill. It only requires pre-excavating cuts along the coal pillars uphill and downhill to form a complete working face production system, after which mining can begin. Fresh air flows in the same direction as the advance, and during mining, the entire goaf is filled and roadways are left. By completely filling the goaf space with inorganic, non-combustible paste material, from a disaster prevention perspective, problems such as air leakage in the goaf and the threat of spontaneous combustion to the working face, common in conventional forward-advancing mining, can be effectively avoided.

[0065] Backfilling, as a fire prevention and extinguishing measure, can effectively reduce the risk of spontaneous combustion of residual coal in goaf areas by using backfilling mining. It can also extend the coal seam ignition period, reduce the range of oxidation zones in goaf areas, and help prevent spontaneous combustion of coal seams.

[0066] Regarding equipment optimization, unit supports 7 with cantilever beams and end hydraulic supports with added side wing structures were installed, allowing personnel to perform permanent support work under the hydraulic supports. Simultaneously, isolation formwork 8 and unit supports 7 were used to reinforce the support in the roadway area for a period of one month's mining distance, ensuring safe and unobstructed access to the subsequent roadway.

[0067] To ensure the coal mining machine can cut through the headstock, a transition frame for the rocker arm is added to improve the cutting and roadway retention capacity of the working face. The conventional matching scheme between the scraper conveyor and the coal mining machine results in an unloading point of 0.5-0.8 meters for the coal mining machine's drum cutting head, which is insufficient for the passage of equipment such as the transfer conveyor 9 and the crusher. Therefore, considering the working face conditions, a transition frame of 0.4 meters is installed on the rocker arm of the coal mining machine, achieving an unloading point of over 2.0 meters for the coal mining machine's drum cutting head, thus meeting the requirements for unit support installation and the passage of equipment such as the transfer conveyor 9 and the crusher.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel advanced mechanized mining method with dense backfilling, characterized in that, include: Pre-excavation of cutting holes along the coal pillars at the top and bottom of the mining area forms a production system with an advancing working face; The coal mining machine, scraper conveyor, and transfer conveyor are used in tandem to mine solid coal. After mining, the goaf is continuously injected with inorganic non-flammable paste material through pipelines and completely filled with it. The paste material has a uniaxial compressive strength of ≥3.5MPa after 28 days of solidification. After the filling material solidifies, it forms a goaf-side roadway near the roadway, which serves as the mining roadway for the next working face. At the equipment end, the coal mining machine is equipped with a rocker arm transition frame, the scraper conveyor head structure is modified, the transfer machine is equipped with a rear dragging device, and the end support is equipped with side wing guard plates to achieve synchronous equipment advancement and roadway support.

2. The novel compacted backfilling method for advanced fully mechanized mining according to claim 1, characterized in that: The goaf-side roadways on both sides of the filling body are respectively the transport roadway and the material roadway, and the goaf-side roadways are connected to the main transport roadway and / or return air roadway of the mining area.

3. The novel compacted backfilling method for advanced fully mechanized mining according to claim 1, characterized in that: The goaf-retaining area is reinforced with isolation formwork and unit supports, with a support length of not less than one month's mining distance.

4. The novel compacted backfilling method for advanced fully mechanized mining according to claim 3, characterized in that: The isolation frame and unit support are specifically as follows: The isolation formwork consists of two rows of individual hydraulic supports, π-shaped steel beams, and flame-retardant ventilation duct fabric, with a row spacing of 1.0–1.2m; The unit support is a tracked hydraulic support with an adjustable support height of 2.2–4.0m and an initial support force ≥2400kN / frame; The combined support coverage of the isolation formwork and unit support is 30–50m behind the working face, and moves forward as the working face advances.

5. The novel compacted backfilling method for advanced fully mechanized mining according to claim 1, characterized in that: The inorganic non-combustible paste material is composed of fly ash, cement, gangue powder, water, and a composite early-strength agent, with the following part ratios: 35–45 parts fly ash, 8–12 parts cement, 25–35 parts gangue powder, 15–20 parts water, and 0.5–1.5 parts composite early-strength agent. The slump of the inorganic non-combustible paste material is maintained at 180–220 mm, the initial setting time is 3–5 h, and the final setting time is 6–8 h.

6. The novel compacted backfilling method for advanced fully mechanized mining according to claim 1, characterized in that: A rocker arm transition frame is added between the traction and traveling part of the coal mining machine and the cutting rocker arm.

7. The novel compacted backfilling method for advanced fully mechanized mining according to claim 1, characterized in that: The modified head structure of the scraper conveyor includes: The scraper conveyor eliminates the sprocket box and motor base, and replaces them with an integral π-shaped crossbeam; The center height of the unloading roller at the head of the scraper conveyor is lowered by 150–200 mm to increase the passage space for the transfer machine bridge. The scraper conveyor is equipped with a tiltable maintenance platform on both sides of the head, with a platform width ≥600mm and a load capacity ≥2kN / m².

8. The novel compacted backfilling method for advanced fully mechanized mining according to claim 6, characterized in that: The transfer machine is equipped with a rear dragging device, which includes: The rear universal hinged slip shoe of the transfer machine has a wear-resistant plate welded to the bottom surface of the slip shoe with a thickness of ≥12mm; Multiple sliding cylinders are installed between the rear end of the slipper and the bottom plate of the transfer machine, with a stroke of 0.8-1.2m and a thrust ≥250kN; Multiple sliding cylinders are arranged in combination to allow the tail end of the transfer machine to swing within a horizontal ±10° and a vertical ±5° range.

9. The novel compacted backfilling method for advanced fully mechanized mining according to claim 1, characterized in that: The side wing guard plate of the end support is a telescopic box-type structure with a telescopic stroke of 0.6-1.0m. The front end of the guard plate is hinged to an anti-scraping telescopic beam with an extension length of 0.4-0.6m, and a 5mm thick polymer anti-sticking coal lining plate is laid on its surface.

10. The novel dense-filling forward-moving fully mechanized mining method according to any one of claims 1-9, characterized in that: It also includes online monitoring and intelligent control, specifically: A distributed optical fiber temperature measurement system is pre-buried in the goaf area, with optical fiber spacing of 2-3m, to monitor the internal temperature of the filling body in real time. When the temperature at any measuring point is ≥45℃, the ground grouting station is automatically triggered to increase the moisture content of the paste by 3–5% and reduce the cement ratio. When a laser displacement sensor is installed on the roof of the goaf-stayed roadway, and the roof subsidence exceeds 15mm, the support resistance of the unit support is automatically increased by 10–15%, and an audible and visual alarm signal is issued.

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