A mining method for driving and leaving a roadway without coal pillar for sequential mining

Abstract

The present application relates to a kind of no coal pillar mining method suitable for mining and replacing, including the implementation of wide roadway driving, advance excavates upper section working face rubber transport crossheading;Lag behind upper section working face rubber transport crossheading head a certain distance, a certain width of protective filling body wall is constructed in the crossheading close to non-cutting coal side;After the protective filling body stabilizes, excavate lower section working face return air crossheading along the protective filling body wall, realize no coal pillar mining, during the working face mining, the crossheading of succession working face can be synchronized or has been prepared to complete, mining and replacing is normal or in advance, reduce the same mining area operating site and personnel number, reduce the technical management difficulty and accident risk, no longer set coal pillar between two sections, use protective filling body wall to replace the section coal pillar that should be set in the original adjacent working face, realize section completely no coal pillar mining, realize the high recovery of mining area coal resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mining, in particular to a coal-pillar-free mining method suitable for sequential mining and replacement. BACKGROUND

[0002] With the rapid development of coal-pillar-free roadway protection technology, the technology of driving roadway along goaf and leaving roadway along goaf has gradually become a new idea and effective approach for improving resource recovery rate and prolonging service life of mine.

[0003] Driving roadway along goaf requires driving roadway in a lateral support pressure reduction zone after the influence of upper section working face mining tends to be stable (leaving a small coal pillar or not leaving a coal pillar), and the roadway only suffers from mining influence once, which is easier to maintain than leaving roadway along goaf. However, the coal-pillar-free mining is generally difficult to achieve, and a narrow coal pillar of about 5-8m needs to be left for roadway protection, and in the case of thick coal seam, more coal resources will be lost. Therefore, the technology of driving roadway along goaf is usually only suitable for sequential mining and replacement of working face.

[0004] The traditional technology of leaving roadway along goaf is suitable for sequential mining and replacement of working face. However, the traditional technology of leaving roadway along goaf needs to maintain the roadway behind the working face while mining in the upper section working face, and rebuilds a working and roadway protection body along the goaf in the roadway. Therefore, the traditional technology of leaving roadway along goaf is strongly affected by the mining in the upper section, and is also affected by the advanced abutment pressure during mining in the current section. The two mining influences make it difficult to maintain the roadway, especially in thick coal seam mining, the construction difficulty is greater, the cost of roadway protection is high, and Y-type ventilation of working face needs to be achieved. The construction process and mining process interfere with each other, the technical management is difficult, the number of personnel in the stope is increased, the personnel working in the roadway are in the goaf, and the safety production risk is increased.

[0005] Publication No. CN112647947A discloses a mining area coal-pillar-free mining and driving method, which divides one wing of the mining area into a section and a second section, simultaneously performs driving operation in the section and the second section, and alternately performs mining operation in the section and the second section. Each driving operation includes alternately driving the rubber transport crossheading and the return air crossheading, mining the coal pillar between the rubber transport crossheading and the return air crossheading, and supporting and filling the coal pillar empty roof area. Therefore, one fully mechanized working face and two coal pillar mining working faces need to be arranged in the mining area, and four driving working faces are needed, which causes many working sites and personnel in the same mining area, increases the technical management difficulty and accident risk. SUMMARY

[0006] In view of the above shortcomings of the prior art, the coal-pillar-free mining method suitable for sequential mining and replacement provided by the present application can reduce the number of working sites and personnel in the same mining area, and reduce the technical management difficulty and accident risk.

[0007] The application provides a coal pillar-free driving and remaining roadway mining method suitable for sequential mining, which comprises the following steps.

[0008] S1, wide roadway driving is implemented, and a rubberized transportation crossheading of an upper section working face is driven in advance;

[0009] S2, a rubberized transportation crossheading of the upper section working face is lagged behind, and a roadway protection and filling body wall is constructed in close proximity to a non-mined coal side in the crossheading;

[0010] S3, after the roadway protection and filling body wall is stable, a return air crossheading of a lower section working face is driven along the roadway protection and filling body wall, and the coal pillar-free driving is realized;

[0011] S4, the upper section working face is mined, the roof of the rubberized transportation crossheading of the upper section working face is pre-cracked in advance, and the stability of the roadway protection and filling body wall and the return air crossheading of the lower section working face is maintained;

[0012] S5, the lower section working face is mined, and one cycle of sequential mining of the working face is completed.

[0013] Preferably, in the step S1, the wide roadway driving adopts anchor-mesh-cable combined support.

[0014] Preferably, according to the construction speed of the wide roadway driving and the construction speed of the roadway protection and filling body wall, the lag distance I between the roadway protection and filling body wall construction operation and the rubberized transportation crossheading of the upper section working face is calculated by using the following formula ①:

[0015] S1≥L1*(1-V 1掘 / V 充 )+V 1掘 *t ①

[0016] wherein S1 is the lag distance I, L1 is the total length of the wide roadway driving roadway construction, V 1掘 is the construction speed of the wide roadway driving, V 充 is the construction speed of the roadway protection and filling body wall, and t is the deformation stability time of the wide roadway driving.

[0017] Preferably, in the step S2, the filling template used for constructing the roadway protection and filling body wall adopts a steel template or a flexible template.

[0018] Preferably, in the step S2, the filling material used for constructing the roadway protection and filling body wall is selected from one of the following solid materials: a high-water material, concrete, industrial waste residue or a cementitious material.

[0019] Preferably, in the step S3, according to the time for the roadway protection and filling body wall to reach the strength and the construction speed of the return air crossheading of the lower section working face, the lag distance II between the return air crossheading of the lower section working face and the roadway protection and filling body wall construction operation is calculated by using the following formula ②:

[0020] S2 >= L2*(1-V 2掘 / V 充 )+V 2掘 *t 充 ②

[0021] Wherein, S2 is the hysteresis distance II, L2 is the total length of the lower section working face return air gateway construction, V 2掘 is the lower section working face return air gateway construction speed, V 充 is the support filling wall construction speed, t 充 is the time of support filling wall reaching strength.

[0022] Preferably, in step S4, according to the influence range of the advanced support pressure during the upper section working face mining, the roof blasting pre-fracturing of the upper section working face rubber transport gateway is constructed.

[0023] Preferably, in step S4, after the support filling wall construction in the whole roadway is completed, the lower section working face return air gateway driving operation is constructed, realizing the mining and driving operation arrangement of one mining face and one driving working face in one mining area.

[0024] Preferably, in step S4, for the mine without the implementation of explosive blasting, the water jet cutting, hydraulic fracturing technology or static expanding agent is adopted to pre-damage the roof of the upper section working face rubber transport gateway, to cut off the basic roof beam under the action of mine pressure, to reduce the length of the basic roof suspension roof, and to reduce the influence of the basic roof suspension roof on the stability of the support filling body and the lower section working face return air gateway.

[0025] Preferably, in step S4, the working face rubber transport gateway driving is in place, the working face open-off cut and the rubber transport gateway through are constructed, the full negative pressure ventilation system is formed, and the working face mining equipment is installed to carry out the working face mining.

[0026] Compared with the prior art, the mining method provided by the application has the beneficial effects that:

[0027] 1、The gateway driving of the connecting working face can be carried out synchronously or has been prepared to be completed during the working face mining, the mining and driving are normal or advanced, and at the same time, the same coal seam in one mining (panel) area is arranged with at most one working face and two coal (half coal rock) gateway driving working faces, the number of operation sites and personnel in the same mining area is reduced, and the technical management difficulty and accident risk are reduced.

[0028] 2、The coal pillar between two sections is not reserved, the section coal pillar reserved by the original adjacent working face is replaced by the support filling wall, the section is completely mined without coal pillar, and the high recovery rate of the mining (panel) area coal resources is realized.

[0029] 3、The upper section working face return air crossheading of the present application is advanced to the upper section working face recovery, but can be reserved during the recovery of the upper section working face, and the stress environment and the use function are the same as the traditional gob-side entry retaining, but the problem of mutual interference and influence during the construction process of the traditional gob-side entry retaining is solved, and the problem of Y-shaped ventilation of the entry retaining working face is avoided.

[0030] 4、The roadway protection filling body of the present application is equivalent to the "rock pillar" roadway protection, and can reasonably design the width and strength of the concrete filling body through the concrete material selection and proportioning experiment according to the characteristics that the strength of the concrete filling body is higher than the strength of the coal pillar, so as to realize the stability of the roadway, ensure the safety, save the concrete filling material, improve the working efficiency and the supporting effect. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the profile schematic diagram of the upper section working face rubber conveying crossheading wide roadway excavation of the present application;

[0032] Figure 2 is the profile schematic diagram of the construction position of the roadway protection filling body wall of the present application;

[0033] Figure 3 is the profile schematic diagram of the lower section working face return air crossheading excavation of the present application;

[0034] Figure 4 is the profile schematic diagram of the upper section working face recovery of the present application;

[0035] Figure 5 is the profile schematic diagram of the lower section working face recovery of the present application.

[0036] BRIEF DESCRIPTION OF DRAWINGS

[0037] 1-coal seam; 2-direct roof; 3-primary roof; 4-upper section working face rubber conveying crossheading; 5-upper section recovery area; 6-lower section recovery area; 7-roadway protection filling body wall; 8-lower section working face return air crossheading; 9-upper section working face goaf; 10-lower section working face goaf; 11-broken roadway protection filling body. DETAILED DESCRIPTION

[0038] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Figures 1 to 5 It should be understood that the protection scope of the present application is not limited by the specific embodiments.

[0039] As shown in Figures 1 to 5 , the present application provides a coal pillar-free entry retaining and mining method suitable for sequential mining, as shown in Figure 1As shown, the top of the coal seam 1 is the immediate roof 2 and the main roof 3, S1, the wide roadway driving, the upper section working face rubber transport gate 4 is dug out in advance, the upper section working face rubber transport gate 4 on one side is the upper section mining area 5, and the other side is the lower section mining area 6, the wide roadway driving adopts the anchor net cable combined support, the upper section working face rubber transport gate 4 can be driven according to the designed use area during mining, and after the construction is in place, the side is expanded, supported and constructed with the roadway filling body wall 7.

[0040] S2, the upper section working face rubber transport gate is lagged by a certain distance, and a certain width of the roadway filling body wall 7 is constructed in the gate close to the non-cutting coal side; according to the wide roadway driving speed and the roadway filling body wall 7 construction speed, the lag distance between the roadway filling body wall 7 construction operation and the upper section working face rubber transport gate head is determined according to the principle of coordination; the filling template used for constructing the roadway filling body wall 7 can adopt a steel template or a flexible template; the filling material used for constructing the roadway filling body wall 7 can adopt high water material, concrete, or solid material composed of industrial waste residue and cement and other cementitious substances;

[0041] The lag distance I between the roadway filling body wall 7 construction operation and the upper section working face rubber transport gate head is calculated by using the following formula ①:

[0042] S1≥L1*(1-V 1掘 / V 充 )+V 1掘 *t ①

[0043] Wherein, S1 is the lag distance I, L1 is the total length of the wide roadway driving roadway construction, V 1掘 is the wide roadway driving construction speed, V 充 is the roadway filling body wall 7 construction speed, and t is the wide roadway driving deformation stabilization time, which is the actual time of the deformation amount stabilization of the wide roadway driving in the actual construction process.

[0044] S3, after the roadway filling body wall 7 is stabilized, the lower section working face return air gate 8 is driven along the roadway filling body wall 7, and the roadway driving without coal pillar is realized; according to the time when the roadway filling body reaches the strength and the driving construction speed of the lower section working face return air gate 8, the lag distance between the lower section working face return air gate 8 and the roadway filling body wall 7 construction operation is determined, and the mining and driving operation arrangement of one mining area with one mining face and two driving working faces is realized. The working face rubber transport gate is driven in place, the working face cut and the rubber transport gate are connected, the full negative pressure ventilation system is formed, and the working face mining equipment is installed for working face mining;

[0045] The lag distance II between the lower section working face return air gate 8 and the roadway filling body wall 7 construction operation is calculated by using the following formula ②:

[0046] S2≥L2*(1-V2掘 / V 充 )+V 2掘 *t 充 ②

[0047] Where S2 is the lag distance II, L2 is the total construction length of the return air roadway 8 in the lower section working face, and V 2掘 To determine the construction speed of the return air roadway 8 in the lower section working face, V 充 To ensure the construction speed of the infill wall for the tunnel, t 充 The time required for the infill wall of the tunnel to reach its strength.

[0048] S4, upper section working face back mining, forming as follows Figure 4 In the upper section working face goaf 9 shown, the roof is pre-fractured in the upper section working face conveyor roadway 4 to maintain the stability of the roadway backfill and the lower section working face return airway 8. Based on the influence range of the advance support pressure during the upper section working face mining, the location of the pre-fractured roof in the upper section working face conveyor roadway 4 and the blasting pre-fracture roof breaking technical parameters such as borehole length, angle, spacing, and charge amount are reasonably determined. For mines that do not have the conditions to carry out explosive blasting, hydraulic fracturing technology and static expansion agents can be used to pre-break the roof in the upper section working face conveyor roadway 4 in advance. Under the action of mine pressure, the basic roof rock beam is cut off, the length of the basic roof overhang is reduced, and the impact of the basic roof overhang on the stability of the roadway backfill and the lower section working face return airway 8 is reduced, thus maintaining the integrity of the roadway backfill.

[0049] S5, the lower section working face is mined, forming as follows Figure 5 The lower section working face goaf 10 is shown. After completing one cycle of working face succession, the lower section working face return airway 8 will be excavated after the construction of the entire roadway protection and filling wall 7 is completed. This can realize a mining operation layout scheme of one mining area equipped with one mining face and one excavation working face.

[0050] Example

[0051] This embodiment takes the excavation of the haulage roadway of the 52202 working face and the return air roadway of the 52204 working face of a certain mine as examples to provide a detailed description of a pillarless roadway mining method suitable for the succession of conventional mining. The 52202 working face roadway is designed with a rectangular cross-section and is excavated at a width of 7.4m. A 2m section for the protective roadway filling body is reserved on the non-cutting coal side. The protective roadway filling body is constructed 500m after the face. The width used during mining is 5.4m and the height is 3.8m. After the construction of the 52202 working face roadway and the 2m protective roadway filling body is completed, the 52204 working face return air roadway is constructed along the protective roadway filling body. It is designed with a rectangular cross-section, with a width of 5.0m and a height of 3.8m. The excavation face is excavated along the bottom. The top coal is 3.0m thick. The immediate roof is mudstone and siltstone, with thicknesses of 4.5m and 2.4m respectively. The main roof is fine-grained sandstone with a thickness of 7.7m. The coal seam mining height is 3.8m.

[0052] Based on the engineering geology and production conditions of the mine, reasonable parameters for the strength and width of the filling body and the technical parameters for roadway support were determined through theoretical calculations and numerical simulation analysis: When the width of the filling body is 2m, the concrete strength grade needs to reach C30 or above. The roadway support adopts a combined anchor-mesh-cable support form. The anchor rods are left-hand threaded high-strength anchor rods, with the anchor rod model being MSGLW-335. The yield strength of the rod body is not less than 335MPa, the ultimate strength is not less than 490MPa, and the elongation is 17%. The anchor tail is subjected to heat treatment to strengthen it, with a yield strength not less than that of the rod body. The thread specification of the rod tail is M22, and it is formed by rolling processing.

[0053] The tunnel roof slab adopts Left-hand threaded high-strength anchor bolts are used, employing extended anchoring. The drill bit diameter is 28mm, and the borehole diameter is less than 30mm. Each anchor bolt hole contains two resin anchoring agents: one K2335 and one Z2360. Eight anchor bolts are arranged on the top slab, spaced 1000mm apart, with a row spacing of 1000mm. The anchor bolt anchoring force is designed to be 100kN, and the pre-tightening moment is not less than 300N·m. A steel mesh is used as auxiliary support on the top slab. The steel-reinforced welded mesh measures 7400mm × 1100mm, with each mesh measuring 100mm × 100mm. Adjacent meshes overlap by approximately 100mm, connected by wire buttons at 200mm intervals, with each button twisted at least three times. Four anchor bolts are installed on each side of the tunnel, with other parameters identical to those for the roof support. The anchor cables are made of 1×7 strands of high-strength, low-relaxation steel strand with a diameter of… Three anchor cables, each 5800mm long, are arranged in a row with a spacing of 2000mm and a row spacing of 2000mm. They are anchored using one K2335 and two Z2360 resin anchoring agents. The anchoring force is designed to be 320kN, with a preload of ≥230kN. The cables are mounted on a 300mm×300mm×15mm high-strength spherical tray, and are equipped with self-aligning ball pads, nylon washers, and locks.

[0054] 52202 During the working face mining, the roof hydraulic fracturing is constructed 100 m ahead of the working face. The pre-fracturing angle of the roof is determined as 10° through calculation. The construction is conducted at 1 m outside the filling body. The hole depth is 26.6 m. The hole spacing is 5 m. The lower main roof is cut off by using the mine pressure.

[0055] The above disclosed are only the preferred embodiments of the present application, but the embodiments of the present application are not limited to this. Any changes that can be thought of by any person skilled in the art shall fall within the protection scope of the present application.

Claims

1. A coal pillarless mining method suitable for sequential recovery, characterized in that, The method comprises the following steps: S1, wide lane excavation is implemented, and a rubber transportation crossheading (4) of an upper section working face is excavated in advance; S2, a rubber transportation crossheading of the upper section working face is lagged, and a roadway protection and filling body wall (7) is constructed in close proximity to a non-cutting coal side in the crossheading; in step S2, a lag distance I between the roadway protection and filling body wall (7) construction operation and the rubber transportation crossheading of the upper section working face is calculated according to the wide lane excavation construction speed and the roadway protection and filling body wall (7) construction speed by using the following formula ①: S1≥ L1*(1-V) + V 1掘 / V 充 )+V 1掘 *t ① Wherein, S1 is the hysteresis distance I, L1 is the total length of the wide roadway driving construction, V 1掘 is the wide roadway driving construction speed, V 充 is the construction speed of the roadway protection filling body wall (7), t is the wide roadway driving deformation stability time; S3, after the roadway protection and filling body wall (7) is stable, a return air crossheading (8) of a lower section working face is excavated along the roadway protection and filling body wall (7), and the lane is excavated without a coal pillar; a lag distance II between the return air crossheading (8) of the lower section working face and the roadway protection and filling body wall (7) construction operation is calculated according to the time when the roadway protection and filling body wall (7) reaches the strength and the return air crossheading (8) construction speed of the lower section working face by using the following formula ②: S2≥ L2 * (1 - V 2掘 / V 充 )+V 2掘 *t 充 ② Wherein, S2 is the hysteresis distance II, L2 is the total length of the lower section working face return air gateway (8) construction, V 2掘 is the construction speed of the lower section working face return air gateway (8), V 充 is the construction speed of the gateway protection and filling body wall (7), t 充 is the time for the gateway protection and filling body wall (7) to reach strength; S4, the upper section working face is mined, the roof of the rubber transportation crossheading of the upper section working face is pre-split in advance, and the stability of the roadway protection and filling body wall (7) and the return air crossheading (8) of the lower section working face is maintained; S5, the lower section working face is mined, and one cycle of the working face is completed.

2. A coal pillarless gateway mining method suitable for progressive replacement as claimed in claim 1, characterised in that, In step S1, the wide lane excavation adopts anchor net and cable combined support.

3. A coal pillarless gateway mining method suitable for progressive replacement as claimed in claim 1, characterised in that, In step S2, the filling template used for constructing the roadway protection and filling body wall (7) adopts a steel template or a flexible template.

4. The coal pillarless gateway mining method for sequential extraction and replacement of claim 1, wherein, In step S2, the filling material used for constructing the roadway protection and filling body wall (7) selects one of high water material, concrete, industrial waste residue or cement.

5. A coal pillarless gateway mining method suitable for progressive retreat mining as claimed in claim 1, characterised in that, In step S3, after the construction of the roadway protection and filling body wall (7) in the whole lane is completed, the return air crossheading (8) of the lower section working face is constructed, and a mining and excavation operation arrangement of one mining face and one excavation working face in one mining area is realized.

6. A coal pillarless gateway mining method suitable for progressive retreat mining as claimed in claim 1 wherein, In step S4, for a mine without explosive blasting, a hydraulic cutting seam, a hydraulic fracturing technology or a static expanding agent is used to pre-damage the roof in the rubber transportation crossheading (4) of the upper section working face, and the basic roof beam is cut off under the action of the mine pressure.

7. A coal pillarless gateway mining method suitable for progressive retreat mining as claimed in claim 1 wherein, In step S4, during the mining of the upper section working face, the roof blasting pre-splitting is performed in the rubber transportation crossheading (4) of the upper section working face outside the influence range of the working face support pressure.

8. A coal pillarless gateway mining method suitable for progressive retreat mining as claimed in claim 1 wherein, In step S4, after the rubber transportation crossheading is excavated to the position, the working face cut and the rubber transportation crossheading are constructed, a full negative pressure ventilation system is formed, and the working face mining equipment is installed to mine the working face.

Images