Overlying strata isolation grouting filling method for multi-coal-seam mining

Abstract

The invention belongs to the field of coal mine filling mining, and particularly relates to an overlying strata isolation grouting filling method for multi-coal-seam mining. Numbering according to the coal seam elevation from small to large; the caving zone range of each coal seam is determined, and for a certain coal seam, the mining sequence of other coal seams in the caving zone range must be prior to the certain coal seam; determining the elevation of a water flowing fractured zone of each coal seam, and on the basis of the mining sequence, re-numbering each coal seam according to the elevation of the water flowing fractured zone in a sequence from small to large; and sequentially performing overlying strata isolation grouting filling mining on each coal seam according to the re-numbered sequence. The technical scheme of overlying strata isolation grouting filling for multi-coal-seam mining is researched on the basis of the characteristics of a caving zone and a water flowing fissure zone of a coal seam, and the problem that existing overlying strata isolation grouting filling is mostly used for single-coal-seam mining is solved; according to the method, safe and efficient mining of all coal seams and the overall grouting filling subsidence control effect can be guaranteed to the maximum extent.

Description

Technical Field

[0001] The invention belongs to the field of coal mine filling mining, and specifically relates to a multi-coal seam mining overburden isolation grouting filling method. Background Art

[0002] Mining coal under buildings (structures) has always been a major problem that has troubled coal enterprises. Solving the problem of mining coal under buildings (structures) can promote the coordinated development of industry and agriculture in mining areas. Backfill mining technology is a common method for mining coal under buildings (structures), mainly including backfilling of goaf (such as solid dense backfilling, paste backfilling, high water backfilling) and overburden isolation grouting backfilling technology. Overburden isolation grouting backfilling technology is to divide the mining area into several coal mining faces, construct several groups of grouting boreholes perpendicular to the coal seam from the surface above the coal mining face, and inject fly ash slurry into the layered fissures of the overburden above the coal mining face through the grouting boreholes during the mining process of the working face, so as to effectively control the surface subsidence and realize coal mining without relocating villages. However, existing research and engineering practice are mostly used for overburden isolation grouting backfilling under single coal seam conditions, and there is little research on the mining sequence of each coal seam under multi-coal seam conditions and the corresponding mining and grouting backfilling schemes (working face layout, grouting layer, etc.) for each coal seam. Summary of the invention

[0003] In view of the deficiencies in the above-mentioned prior art, the present invention proposes a method for isolation grouting of overburden in multi-coal seam mining, comprising the following steps:

[0004] A method for grouting and filling in overburden isolation for multi-coal seam mining is applicable to working conditions where there are multiple coal seams in the stratum, and comprises the following steps:

[0005] a. Number each coal seam in ascending order according to its elevation, #1 to #N;

[0006] b. Determine the range of the collapse zone when each coal seam is mined separately, and judge in sequence according to the numbering order of step a whether the #Nth coal seam of the #i+1 coal seam is located within the collapse zone of the #i coal seam when the #i coal seam is mined, 1≤i≤N-1; if the #i+1 coal seam to the i+1+kth coal seam are located within the collapse zone of the #i coal seam, then the mining order of the #i+1 coal seam to the i+1+kth coal seam must be prior to the #i coal seam, 0≤k; that is, for a certain coal seam, the overburden isolation grouting filling mining order of other coal seams located within its collapse zone must be prior to that of the certain coal seam;

[0007] c. Determine the scope of the water-conducting fracture zone when each coal seam is mined separately, and then find the corresponding water-conducting fracture zone elevation when each coal seam is mined separately, and renumber each coal seam in order from small to large according to the water-conducting fracture zone elevation without destroying the overburden isolation grouting filling mining sequence determined in step b;

[0008] d. Determine the grouting layer of each coal seam. The grouting layer of each coal seam is based on the elevation of its water-conducting fracture zone plus a certain thickness of isolation layer;

[0009] e. Carry out overburden isolation grouting filling mining for each coal seam in the order of renumbering.

[0010] Preferably, the working faces of adjacent mining sequence coal seams are arranged in a staggered manner in terms of inclination.

[0011] Beneficial effects: The present invention studies the technical scheme of overburden isolation grouting and filling for multi-coal seam mining based on the characteristics of the collapse zone and water-conducting fracture zone of the coal seam; for a certain coal seam, the overburden isolation grouting and filling mining order of other coal seams within its collapse zone must be prior to that of the certain coal seam; on the basis of not destroying the above principles, overburden isolation grouting and filling mining is carried out for each coal seam in the order from small to large according to the elevation of the water-conducting fracture zone. The present invention solves the problem that the existing overburden isolation grouting and filling is mostly used for single coal seam mining, and can guarantee the safe and efficient mining of each coal seam and the overall grouting and filling subsidence control effect to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the multi-coal seam working condition of the present invention;

[0013] Figure 2 It is a schematic diagram of the staggered arrangement of adjacent mining sequence coal seams of the present invention;

[0014] Figure 3 Schematic diagram of coal seam parameters in Example 2 of the present invention (unit: m);

[0015] In the figure: working face 10 relative to the first coal seam, isolation coal pillar 11 relative to the first coal seam, grouting layer 12 relative to the first coal seam, grouting borehole 13 relative to the first coal seam, grouting body 14 relative to the first coal seam, working face 20 relative to the later coal seam, isolation coal pillar 21 relative to the later coal seam, grouting layer 22 relative to the later coal seam, grouting borehole 23 relative to the later coal seam, grouting body 24 relative to the later coal seam. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described in more detail below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0017] Example 1: There is at most one other coal seam within the collapse zone of any coal seam

[0018] A method for grouting and filling in overburden isolation for multi-coal seam mining is applicable to working conditions where there are multiple coal seams in the stratum, and comprises the following steps:

[0019] a. Number each coal seam in order from small to large (from deep to shallow) according to the coal seam elevation (or burial depth), #1 to #N;

[0020] b. Determine the range of the collapse zone when each coal seam is mined separately. When the #i coal seam is mined, determine in sequence according to the numbering order of step a whether the #i+1 coal seam is located within the collapse zone of the #i coal seam, 1≤i≤N-1; if the #i+1 coal seam is located within the collapse zone of the #i coal seam, then the mining order of the #i+1 coal seam must precede that of the #i coal seam; that is, for two adjacent coal seams, if the relatively upper coal seam is located within the collapse zone of the relatively lower coal seam, then the mining order of the overburden isolation grouting filling of the relatively upper coal seam must precede that of the relatively lower coal seam. This is defined as the first principle;

[0021] c. Determine the scope of the water-conducting fracture zone when each coal seam is mined separately, and then find the corresponding water-conducting fracture zone elevation when each coal seam is mined separately. On the basis of not violating the first principle, renumber each coal seam in the order from small to large (from deep to shallow) according to the elevation (burial depth) of the water-conducting fracture zone;

[0022] The second principle is defined as mining each coal seam by isolation grouting and filling according to the elevation of the water-conducting fracture zone in the order from small to large. The second principle must be subject to the first principle, that is, the second principle cannot destroy the first principle, that is, the first principle is preferred to the second principle; for example, if the relatively upper coal seam is located in the collapse zone of the relatively lower coal seam, and the elevation of the water-conducting fracture zone of the relatively upper coal seam is greater than that of the relatively upper coal seam (the buried depth of the water-conducting fracture zone of the relatively lower coal seam is relatively deep), the relatively upper coal seam shall be mined first;

[0023] d. Determine the grouting layer of each coal seam. The grouting layer of each coal seam is based on the elevation of its water-conducting fracture zone plus an 80m thick isolation layer;

[0024] e. Figure 2 As shown, each coal seam is mined in turn by overburden isolation grouting filling in the order of renumbering, and the working faces of adjacent mining sequence coal seams are arranged in a staggered manner in the inclination (in the direction of the width of the working face).

[0025] Embodiment 2: There is at most one other coal seam within the collapse zone of any coal seam, and there are 4 coal seams in the stratum;

[0026] like Figure 3 As shown, for the working condition where there are four coal seams in the stratum, the multi-coal seam mining overburden isolation grouting filling method of the present invention includes the following steps:

[0027] a. According to the coal seam elevation (column B), the coal seams are numbered in ascending order, namely #1, #2, #3, and #4 (column A);

[0028] b. Determine the collapse zone range of each coal seam when it is mined separately (column C). According to the numbering order of step a, determine whether the #i+1 coal seam is located within the collapse zone range of the #i coal seam when the #i coal seam is mined, 1≤i≤N-1; the result is: the #2 coal seam is not located within the collapse zone range of the #1 coal seam; the #3 coal seam is not located within the collapse zone range of the #2 coal seam; the #4 coal seam is located within the collapse zone range of the #3 coal seam, then the mining order of the #4 coal seam must be before the #3 coal seam;

[0029] c. Determine the range of the water-conducting fracture zone when each coal seam is mined separately (column E), and then find the corresponding water-conducting fracture zone elevation when each coal seam is mined separately (column F). Without violating the first principle, renumber each coal seam in the order from small to large (from deep to shallow) according to the elevation (burial depth) of the water-conducting fracture zone (column H);

[0030] Only according to the elevation (burial depth) of the water-conducting fracture zone, the original #1, #2, #3, #4 (column A) should be renumbered in the order from small to large (from deep to shallow). The original #1, #2, #3, #4 (column A) should be adjusted to #2, #1, #3, #4. However, since the first principle is superior to the second principle, the original #4 coal seam must be prior to the #3 coal seam. Therefore, the original #1, #2, #3, #4 (column A) is finally renumbered to #2, #1, #4, #3 (column G);

[0031] d. Determine the grouting layer of each coal seam. The grouting layer of each coal seam is based on the elevation of its water-conducting fracture zone plus an 80m thick isolation layer (H column);

[0032] e. Figure 2 As shown, each coal seam is mined in turn by overburden isolation grouting filling in the order of renumbering, and the working faces of adjacent mining sequence coal seams are arranged in a staggered manner in the inclination (in the direction of the width of the working face).

[0033] Embodiment 3: Applicable to the working condition where there is at least one coal seam and one or more other coal seams within the collapse zone

[0034] A method for grouting and filling in overburden isolation for multi-coal seam mining is applicable to working conditions where there are multiple coal seams in the stratum, and comprises the following steps:

[0035] a. Number each coal seam in order from small to large (from deep to shallow) according to the coal seam elevation (or burial depth), #1 to #N;

[0036] b. Determine the range of the collapse zone when each coal seam is mined separately. When the #i coal seam is mined, determine in sequence according to the numbering order of step a whether the #Nth coal seam of the #i+1 coal seam is located within the collapse zone of the #i coal seam, 1≤i≤N-1; if the #i+1 coal seam to the i+1+kth coal seam are located within the collapse zone of the #i coal seam, then the mining order of the #i+1 coal seam to the i+1+kth coal seam must be prior to the #i coal seam, 0≤k; that is, for a certain coal seam, the overburden isolation grouting filling mining order of other coal seams within its collapse zone must be prior to that coal seam, and this is defined as the first principle;

[0037] Assuming that the #3 and #4 coal seams above the 2# coal seam are both located in the collapse zone of the 2# coal seam, the overburden isolation grouting filling mining order of the #3 and #4 coal seams must be prior to the #2 coal seam. If the #4 coal seam above the 3# coal seam is also located in the collapse zone of the 3# coal seam, the overburden isolation grouting filling mining order of the #4 coal seam must be prior to the #3 coal seam, that is, the 4# coal seam is prior to the #3 coal seam, and the #3 coal seam is prior to the 2# coal seam for overburden isolation grouting filling mining;

[0038] c. Determine the scope of the water-conducting fracture zone when each coal seam is mined separately, and then find the corresponding water-conducting fracture zone elevation when each coal seam is mined separately. On the basis of not violating the first principle, renumber each coal seam in the order from small to large (from deep to shallow) according to the elevation (burial depth) of the water-conducting fracture zone;

[0039] The second principle is defined as mining each coal seam by isolation grouting and filling according to the elevation of the water-conducting fracture zone in the order from small to large. The second principle must be subject to the first principle, that is, the second principle cannot destroy the first principle, that is, the first principle is preferred to the second principle; for example, if the relatively upper coal seam is located in the collapse zone of the relatively lower coal seam, and the elevation of the water-conducting fracture zone of the relatively upper coal seam is greater than that of the relatively upper coal seam (the buried depth of the water-conducting fracture zone of the relatively lower coal seam is relatively deep), the relatively upper coal seam shall be mined first;

[0040] d. Determine the grouting layer of each coal seam. The grouting layer of each coal seam is based on the elevation of its water-conducting fracture zone plus an 80m thick isolation layer;

[0041] e. Figure 2 As shown, each coal seam is mined in turn by overburden isolation grouting filling in the order of renumbering, and the working faces of adjacent mining sequence coal seams are arranged in a staggered manner in the inclination (in the direction of the width of the working face).

[0042] It should be noted that the solution of the third embodiment is applicable to the working conditions of the first embodiment.

[0043] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. The overburden isolation grouting filling method for multi-coal seam mining is applicable to the working condition where there are multiple coal seams in the stratum, and is characterized by: The steps include: a. Number each coal seam in ascending order according to its elevation, #1 to #N; b. Determine the range of the collapse zone when each coal seam is mined separately, and judge in sequence according to the numbering order of step a whether the #Nth coal seam of the #i+1 coal seam is located within the collapse zone of the #i coal seam when the #i coal seam is mined, 1≤i≤N-1; if the #i+1 coal seam to the i+1+kth coal seam are located within the collapse zone of the #i coal seam, then the mining order of the #i+1 coal seam to the i+1+kth coal seam must be prior to the #i coal seam, 0≤k; that is, for a certain coal seam, the overburden isolation grouting filling mining order of other coal seams located within its collapse zone must be prior to that of the certain coal seam; c. Determine the scope of the water-conducting fracture zone when each coal seam is mined separately, and then find the corresponding water-conducting fracture zone elevation when each coal seam is mined separately, and renumber each coal seam in order from small to large according to the water-conducting fracture zone elevation without destroying the overburden isolation grouting filling mining sequence determined in step b; d. Determine the grouting layer of each coal seam. The grouting layer of each coal seam is based on the elevation of its water-conducting fracture zone plus a certain thickness of isolation layer; e. Carry out overburden isolation grouting filling mining for each coal seam in the order of renumbering.

2. The method for grouting and filling for overburden isolation in multi-coal seam mining according to claim 1, characterized in that: The working faces of adjacent mining coal seams are arranged in a staggered manner in terms of inclination.

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