Near-full-coal filling method and near-full-coal filling material for outburst mine fully mechanized caving face passing empty roadway

Abstract

The invention discloses an outburst mine fully mechanized caving face empty roadway passing near-full-coal filling method and a near-full-coal filling material, and belongs to the technical field of mine filling materials. The outburst mine fully mechanized caving face empty roadway passing near-full-coal filling method comprises the following steps that S1, fully mechanized caving face coal rock stratum physical and mechanical parameters and mining technical parameters are obtained; s2, acquiring basic characteristics of the goaf roadway, wherein the basic characteristics comprise the section shape, the section size, the roadway length, the inclination angle and the azimuth angle of the goaf roadway, the distance between the top and bottom plates of the goaf roadway and the top and bottom plates of the coal seam, the supporting mode and parameters of the goaf roadway, and the type and the concentration of gas in the goaf roadway; s3, determining an in-situ filling method and material for the outburst mine fully mechanized caving face to pass through the gob roadway: preparing the filling material which can be applied to different scenes by taking lump coal, slack coal and slime water generated by underground mining and pulverized coal slag formed by drilling as main raw materials, so that local material utilization and in-situ filling are realized; and the influence of the filling body on the coal mining efficiency and the coal quality is reduced, and the mine filling cost and the washing cost are greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine filling materials, and specifically refers to a nearly full coal filling method for an empty tunnel in a fully mechanized caving working face of a prominent mine and a nearly full coal filling material. Background Art

[0002] In recent years, with the continuous growth of my country's energy demand, some coal mines have carried out disorderly mining and expansion, and even carried out illegal mining across layers and boundaries, which not only caused the destruction of the original coal fields, but also left a large number of old empty tunnels, which brought great difficulties to the normal mining of the coal mining face. In addition, some coal mines need to pass through old empty tunnels due to changes in mining connection, mining design, etc., or excessive working faces passing through the middle cut eyes. At present, the most commonly used technical method for coal mining faces to pass through empty tunnels is to fill the empty tunnels with cement slurry, gangue-fly ash-cement slurry, coal gangue, blocks, etc. However, since some old empty tunnels are perpendicular or oblique to the working face, or there are multiple old empty tunnels within the mining range of the working face, a large amount of space needs to be filled, that is, the filling body needs to be continuously cut during the mining process, which not only increases the difficulty of crushing and washing and reduces the coal quality, but also aggravates the wear of the coal mining machine pick, reduces the mining speed, and generates cutting sparks, affecting the safe and efficient production of the mine. In addition, for the fully mechanized caving working face, when the old empty tunnel is located in the upper coal discharge area, after filling with cement slurry, gangue-fly ash-cement slurry, etc., it is difficult to release due to its large consolidation strength and strong integrity. In the actual production process, it is specifically manifested as: the filling block blocks the coal discharge port, the filling body hangs on the top for a long distance, and the filling body collapses as a whole over a large area, resulting in major production safety accidents such as reduced recovery rate, severe and abnormal mine pressure, crushing of supports, blockage and stoppage of rear scraper, and collapse of end roof.

[0003] On the other hand, for high-gas and coal seam outburst mines, pre-extraction of coal seam gas by drilling along the layer or through the layer is the most commonly used and effective gas control method. According to incomplete statistics, the annual extraction drilling footage of a single mine in my country is as high as 300,000 to 500,000 meters, and the drill cuttings and coal powder slag generated are 3,500 to 6,000 tons. However, due to the inability to effectively utilize them, mines currently hardly recycle them, resulting in a large waste of resources.

[0004] Therefore, for the old empty tunnels in the fully mechanized caving working face of the prominent mine, developing a nearly full coal tunnel filling method and nearly full coal filling material that can utilize underground raw coal and drill cuttings and coal powder slag has become a major technical challenge in the development of my country's coal industry. Summary of the invention

[0005] In order to overcome the problems mentioned in the above background, the present invention provides a method for nearly full coal filling in empty tunnels in a fully mechanized caving working face in a prominent mine, which at least partially solves the above problems.

[0006] According to the technical solution of the present invention, a method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine is provided, comprising the following steps:

[0007] S1. Obtaining physical and mechanical parameters of coal and rock layers and mining technical parameters of fully mechanized caving working face;

[0008] S2. Obtain the basic characteristics of the old empty tunnel, including the cross-sectional shape, cross-sectional dimensions, tunnel length, inclination, azimuth, the distance between the roof and floor of the old empty tunnel and the roof and floor of the coal seam, the support method and parameters of the old empty tunnel, and the gas type and concentration in the old empty tunnel;

[0009] S3. Determine the on-site filling method and materials for the old empty tunnels in the fully mechanized caving working face of the outburst mine:

[0010] When b≥N and a≤S, the filling method is to select paste filling material and fill it by paste filling method;

[0011] When b≥S and a≤M, the filling method is to select lump coal and grouting filling materials to fill by throwing and grouting combined filling method;

[0012] Among them, a is the elevation of the roof of the old empty tunnel, b is the elevation of the bottom of the old empty tunnel, M is the elevation of the roof of the coal seam, N is the elevation of the bottom of the coal seam, and S is the top boundary elevation of the machine mining range of the comprehensive mining working face. The paste filling material, lump coal and grouting filling material are all made from underground raw coal and drill cuttings and coal powder slag.

[0013] Furthermore, the preparation method of the paste filling material is: sorting the raw coal produced by mining and tunnel excavation in the working face of the mine, and sorting out the foam coal and coal mud water with a particle size of less than 7 mm;

[0014] The coal slurry is subjected to sedimentation and dehydration treatment to obtain concentrated coal slurry with a water content of 20% to 25%;

[0015] Screen the drill cuttings and coal powder slag formed by drilling in the mine to remove impurities;

[0016] The foamed coal, concentrated coal slurry water and coal powder slag are mixed and stirred, cement, additives and mine water are added during the stirring process, and after uniform stirring, a paste filling material with a slurry concentration of 77% to 86% is prepared.

[0017] Furthermore, the preparation method of the lump coal and grouting filling material is:

[0018] The raw coal produced by mining and tunneling in the underground mine is sorted to separate the foamy coal and coal slime water with a particle size of 9-11cm;

[0019] The coal slurry is subjected to sedimentation and dehydration treatment to obtain concentrated coal slurry with a water content of 20% to 25%;

[0020] Screen the drill cuttings and coal powder slag formed by drilling in the mine to remove impurities;

[0021] The concentrated coal slurry water and coal powder slag are mixed and stirred, cement, additives and mine water are added during the stirring process, and after uniform stirring, a grouting filling material with a slurry concentration of 68% to 75% is prepared.

[0022] Furthermore, the paste filling method comprises the following steps:

[0023] Arrange filling columns: Arrange multiple filling columns in the old empty tunnel by injecting filling materials into vertical filling bags, with the distance between adjacent filling columns being the same;

[0024] Anchor withdrawal: Starting from one end of the old empty tunnel close to the cutting direction of the fully mechanized caving working face, the locks, trays, anchor nets, steel belts, etc. of the roof of the old empty tunnel and the two sides of the anchor rope are dismantled and recycled in sequence through the anchor withdrawal device;

[0025] Establishment of filling body: after a single anchor withdrawal is completed, a filling body is established in the old empty tunnel within the distance range of the single anchor withdrawal by using paste filling materials until the old empty tunnel is completely filled.

[0026] Furthermore, the upright filling bag is formed by cutting off a waste wind tube in a mine with a length equal to the height of an old empty tunnel, and gluing and sealing one end opening of the wind tube with a wind tube cloth to form the upright filling bag;

[0027] The open end of the filling bag is hung on the area without anchor rods and cables on the roof of the old empty tunnel by anchor nails, and the paste filling material is injected into the upright filling bag to form a filling column.

[0028] The paste filling material is pumped into the upright filling bag through the grouting hose to form a filling column, and a filling column is established at every end distance in the same way.

[0029] Furthermore, a waste wind tube with a diameter equal to the width of the old empty tunnel is cut, and one end of the cut wind tube is glued and sealed with wind tube cloth, and the other end is glued with wind tube cloth to leave a grouting hole to form a horizontal filling bag, and the filling bag is placed horizontally on the bottom plate of the old empty tunnel, so that the two ends of the horizontal filling bag contact the two sides of the old empty tunnel, and the grouting hose is used to pump the paste filling material into the horizontal filling bag to allow the horizontal filling bag to expand freely. When the paste filling material slurry begins to overflow from the upper grouting hole, the grouting is stopped, the grouting hole is closed, and the two ends of the horizontal filling bag are fixed to the two sides of the tunnel with anchor nails;

[0030] In the same way, a second horizontal filling bag is constructed next to the first horizontal filling bag that has been grouted. After the two filling bags are solidified, a third horizontal filling bag is constructed in the middle position above the two filling bags. The three horizontal filling bags form a filling retaining wall with a height of 0.9-1.1m.

[0031] The grouting hose is used to inject paste filling material slurry into the space enclosed between the filling retaining wall and the old empty tunnel or the filling body until the slurry liquid level is flush with the top surface of the retaining wall.

[0032] Furthermore, the method of combined throwing and grouting filling is specifically as follows:

[0033] Divide the old empty tunnel into multiple filling sections with the same filling step length;

[0034] Starting from one end of the old empty tunnel near the cutting direction of the fully mechanized caving working face, the locks, trays, anchor nets, steel belts, etc. of the roof of the old empty tunnel and the two sides of the anchor rope are dismantled and recycled in turn through the anchor withdrawer;

[0035] After a single anchor withdrawal is completed, the coal blocks are first scattered in the filling single layer, and then the grouting filling material is injected into the gaps between the coal blocks until the slurry liquid level is the same as the top surface of the coal blocks. After all the slurry solidifies, the filling is completed.

[0036] Furthermore, the filling section is divided into a plurality of filling areas of the same height, and the unshielded side of the filling single layer is provided with a retractable backstop;

[0037] During the scattering process, the coal in the filling area is pushed, compacted and leveled by the movement of the gangue filler and the forward and backward extension of the push plate. When the thickness of the coal in the filling area reaches the requirement, the bottom of the push plate is fixed to the ground, and telescopic plates are set on both sides of the retreat plate to make the telescopic plates completely contact the two sides of the old empty tunnel.

[0038] Furthermore, when filling the filling area close to the top wall of the old empty tunnel, adjust the position of the push plate so that its front is close to the side and upper part of the filling body below, and dig a groove in the top plate above the push plate, and let the mouth of the filling pipeline enter the filling space along the hole groove to realize the top filling of the filling area.

[0039] Furthermore, the present invention also provides a nearly full coal filling material for an empty roadway in a fully mechanized caving working face of a protruding mine, including a paste filling material and a pipe filling material;

[0040] The paste filling material comprises the following components in weight percentage: 15% to 30% of coal foam, 10% to 25% of concentrated coal slurry, 20% to 35% of coal powder slag, 5% to 15% of cement, 0.5% to 1.5% of early strength agent, and 0.5% to 1.5% of water reducing agent;

[0041] The grouting filling material comprises the following components in weight percentage: 15% to 30% of concentrated coal mud water, 25% to 40% of coal powder slag, 10% to 20% of cement, 0.5% to 1.5% of early strength agent, and 0.5% to 1.5% of water reducing agent.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] The present invention uses lump coal, frothy coal, coal mud water and coal powder slag formed by drilling produced by underground mining as main raw materials to prepare filling materials that can be applied to different scenarios. The nearly full coal filling material is used to fill the old empty tunnels in the mining face, which not only realizes local material collection and local filling, but also reduces the impact of the filling body on coal mining efficiency and coal quality, and greatly reduces the filling cost and washing cost of the mine.

[0044] The grouting filling material in the present invention will form a heterogeneous filling body when the slurry cements the coal lumps, which can produce a debonding effect under the action of mine pressure and support load to form a loose body, which is equivalent to forming prefabricated cracks for top coal caving, which plays an important role in promoting the smooth caving of top coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic flow diagram of a method for nearly full coal filling in an empty lane of a fully mechanized caving working face according to the present invention;

[0046] Figure 2 It is a schematic diagram of the filling retaining wall after the paste filling of the present invention is completed;

[0047] Figure 3 is a schematic diagram of injecting a first layer of paste filling material according to the present invention;

[0048] Figure 4 It is a schematic diagram of the present invention in which the filling retaining wall is constructed above the solidified first layer of filling body;

[0049] Figure 5 It is a schematic diagram of the present invention completing the grouting of the tunnel within the first section of anchor withdrawal length s;

[0050] Figure 6 are the laboratory property test results of the paste filling materials in Examples 1-6 of the present invention;

[0051] Figure 7 are the laboratory property test results of the grouting filling materials in Examples 1-6 of the present invention;

[0052] Figure 8 These are the laboratory property test results of the cemented bodies formed by lump coal and grouting materials in Examples 1-6 of the present invention.

[0053] In the figure: 1- air duct cloth, 2- filling column, 3- filling retaining wall, 4- old empty tunnel, 5- paste filling body. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection.

[0055] Example 1

[0056] like Figure 1 As shown, when the old empty roadway 4 is completely within the machine mining height range (b≥N and a≤S), a nearly full coal filling method and nearly full coal filling material for the empty roadway of the fully mechanized caving working face in a prominent mine are provided. The specific steps of the method are as follows:

[0057] (1) The raw coal produced by the underground working face recovery and tunnel excavation is transported to the underground TDS intelligent sorting system for sorting, and the froth coal and coal slurry with a particle size of less than 7 mm are sorted out; the coal slurry is precipitated and dehydrated to obtain concentrated coal slurry with a water content of 25%; the drill cuttings and coal powder slag formed by drilling gas layer extraction drilling holes, gas discharge drilling holes and water exploration drilling holes in the underground are screened to remove impurities; the froth coal, concentrated coal slurry and coal powder slag prepared above are mixed and stirred, and cement, additives and mine water filtered in the underground sedimentation tank are added during the stirring process, and the filling material with a slurry concentration of 85% is prepared after stirring, wherein the mass percentage of each component in the filling material is: 30% of froth coal, 10% of concentrated coal slurry, 33% of coal powder slag, 12% of cement, 1% of early strength agent, 1.5% of water reducer, and the balance is mine water;

[0058] (2) Cut a discarded 1000mm diameter wind duct from underground, with the length of the cutoff being equal to the height of the old empty tunnel. Use wind duct cloth 1 to glue and seal the opening of one end of the wind duct to form a vertical filling bag. Use anchor nails to hang the opening of the filling bag on the area without anchor rods and cables on the roof of the old empty tunnel. Pump the grouting material into the filling bag through a 50mm diameter grouting hose to form a filling column 2. In the same way, build a filling column 2 every L distance.

[0059] (3) After the filling column 2 has been consolidated for 3 days, starting from one end of the tunnel close to the cutting direction of the fully mechanized caving working face, the locks, trays, anchor nets, steel belts, etc. of the old empty tunnel roof and the two sides of the anchor rope are dismantled and recovered using an anchor withdrawal device. The length of the tunnel anchor withdrawal is 50m;

[0060] (4) A filling retaining wall 3 composed of air duct filling bags is established at the boundary of the anchor withdrawal range. Specifically: a waste air duct with a diameter of 1000mm is cut off with a length equal to the width of the old empty tunnel 4. One end of the cut air duct is sealed by gluing with air duct cloth 1. The other end is glued with air duct cloth 1 to leave only one grouting hole to form a horizontal filling bag. The filling bag is placed horizontally on the tunnel floor so that both ends of the filling bag contact the two sides of the tunnel. A 50mm diameter grouting hose is used to pump the grouting material into the filling bag so that the filling bag can expand freely. When the slurry begins to overflow from the upper grouting hole, the grouting is stopped, the grouting hole is closed, and the two ends of the filling bag are fixed to the two sides of the tunnel with anchor nails. In the same way, a second filling bag is constructed next to the filling bag that has been grouted. After the two filling bags have been solidified for 24 hours, a third filling bag is constructed in the middle position above the two filling bags, thereby forming a filling retaining wall 3 with a height of about 1m.

[0061] (5) After the third filling bag solidifies for 3 days, a 120 mm diameter grouting hose is used to start grouting into the space enclosed by the filling retaining wall 3 until the grouting liquid level is flush with the top surface of the retaining wall.

[0062] (6) After the slurry solidifies for 3 days, a paste filling body 5 is formed. Steps d to e are repeated to continuously build a filling retaining wall 3 above the solidified filling material and grout it to achieve a dense top filling of the tunnel within the range of 50 m of the anchor withdrawal length.

[0063] (7) After the grouting of the tunnel within the first anchor withdrawal length s is completed, repeat steps c to f, and then fill the tunnel within the rear length s, and repeat this cycle until the entire old empty tunnel 4 is filled.

[0064] like Figure 1 As shown, when the old empty roadway 4 is completely within the coal caving height range (b≥S and a≤M), a nearly full coal filling method and nearly full coal filling material for the empty roadway of the fully mechanized caving working face in a prominent mine are provided. The specific steps of the method are as follows:

[0065] (1) The raw coal produced by the underground working face recovery and tunnel excavation is transported to the underground TDS intelligent sorting system for sorting, and the lump coal and coal slurry with a particle size of about 10 cm are sorted out; the coal slurry is subjected to sedimentation and dehydration treatment to obtain concentrated coal slurry with a water content of 25%; the drill cuttings and coal powder slag formed by drilling gas layer extraction drilling holes, gas discharge drilling holes and water exploration drilling holes in the underground are screened to remove impurities; the concentrated coal slurry water and coal powder slag prepared above are mixed and stirred, and cement, additives and mine water filtered through a sedimentation tank in the underground are added during the stirring process, and after stirring, a filling material with a slurry concentration of 73.5% is prepared, wherein the mass percentage of each component in the filling material is: concentrated coal slurry 25%, coal powder slag 37%, cement 18%, early strength agent 1%, water reducer 1%, and the balance is mine water;

[0066] (2) Improvements are made to the existing gangue filler. First, a new type of airborne temporary support mechanism is installed. Specifically, a lifting jack is welded on the crawler traveling frame on both sides of the gangue filler, a crossbeam is fixedly installed above the two lifting jacks, and a number of multi-stage telescopic rods are fixedly connected to the crossbeam. After the multi-stage telescopic rods are extended and the front rod ends are fixed, a support shelter can be formed; second, a gangue pushing and slurry blocking device is installed. That is, a fixed block is welded on the crawler traveling frame on both sides of the gangue filler, a push jack and a steering jack are installed on the fixed block, and retractable push and baffle plates on both sides are installed in front of the push jack. The height of the retractable push and baffle plates is 1.2m. Its structure and working principle are the same as those of the existing jacks and will not be repeated here.

[0067] (3) According to the advancement direction of the comprehensive caving working face, the old empty tunnel 4 is divided into several filling sections in sequence, with a filling step distance of 30m.

[0068] (4) Overlap the retractable belt conveyor and the feeding belt of the gangue filler, and place the grouting pipeline mouth in the pipe ring below the crossbeam of the temporary support mechanism of the gangue filler. Through the remote control function of the gangue filler, the gangue filler drags the retractable belt conveyor and the filling pipeline to one end of the old empty tunnel close to the cutting direction of the comprehensive mining working face.

[0069] (5) According to the parking position of the gangue filler, 5 holes are drilled at the top of the wall at one end of the old empty tunnel 4. The hole depth is 500mm and the diameter is 110mm. The temporary support mechanism of the gangue filler is opened to extend the telescopic rod and enter the bottom of the hole.

[0070] (6) Use the anchor remover to dismantle and recycle the locks, trays, anchor nets, steel belts, etc. of the 4 roof plates and two sides of the old empty tunnel anchor cables.

[0071] (7) The 10 cm coal blocks produced by the sorting chamber are transported to the gangue filler through a retractable belt conveyor and scattered. During the scattering process, the coal blocks in the filling area are pushed, compacted and leveled through the movement of the gangue filler and the forward and backward extension of the push and baffle plates. When the thickness of the coal in the filling area reaches 1 m, the push and baffle plates are remotely controlled to ground their bottoms, and the telescopic plates on both sides of the push and baffle plates are opened to make the telescopic plates completely contact the two sides of the tunnel.

[0072] (8) Move the grouting pipeline and hang the pipe mouth on the telescopic rod of the temporary support mechanism so that the pipe mouth is located in the middle of the filling area. Turn on the grouting pump to transport the filling material into the gaps between the scattered coal blocks. When the slurry level reaches the height of the coal block accumulation, stop grouting.

[0073] (9) After the slurry solidifies for 3 days, retract the push plate and the telescopic plate, adjust the height of the gangue belt of the gangue filler, and scatter coal blocks into the space above the filling body. During the scattering process, the coal blocks in the filling area are pushed, compacted and leveled by the movement of the gangue filler and the forward and backward extension of the push plate. When the thickness of the fallen coal reaches 1m, the push plate is remotely controlled to stop at the edge above the filling body, and at the same time, the telescopic plates on both sides of the push plate are opened to make the telescopic plates completely contact the two sides of the tunnel.

[0074] (10) Turn on the grouting pump to deliver the filling material into the gaps between the scattered coal lumps. When the slurry level reaches the height of the coal lumps, stop grouting.

[0075] (11) Repeat steps i to j to increase the filling height layer by layer. When filling the last layer, when the scattered coal is about to touch the top, retract the telescopic rod and grouting pipeline of the temporary support mechanism, adjust the position of the push plate so that its front is close to the filling body and the top is touching the top, and dig a groove on the top plate above the push plate, and let the pipe mouth of the filling pipeline enter the filling space along the hole groove to achieve the top filling of the tunnel space of the first filling section.

[0076] (12) Move the gangue filler back one filling step and repeat steps e to k to complete the filling work of the second section, the third section and even the entire tunnel.

[0077] Example 2

[0078] The method of Example 1 is followed, except that the ingredients of paste filling material I are as follows: by mass percentage, 25% coal foam, 20% concentrated coal slurry, 34% coal powder slag, 10% cement, 1% additives, and the balance is mine water, and the total mass percentage of the above substances is 100%, to prepare a nearly full coal paste filling material with a slurry concentration of 83%.

[0079] The operation is carried out according to the method of Example 1, except that the ingredients of grouting filling material II are as follows: calculated by mass percentage, 25% concentrated coal slurry water, 31% coal powder slag, 16% cement, 1.5% additives, and the balance is mine water, and the total mass percentage content of the above substances is 100%, to prepare a nearly full coal grouting filling material with a slurry concentration of 72%.

[0080] Example 3

[0081] The method of Example 1 is followed, except that the ingredients of paste filling material I are as follows: by mass percentage, 22% coal foam, 15% concentrated coal slurry, 32% coal powder slag, 8% cement, 1% additives, and the remainder is mine water, and the total mass percentage of the above substances is 100%, to prepare a nearly full coal paste filling material with a slurry concentration of 81%.

[0082] The operation is carried out according to the method of Example 1, except that the ingredients of grouting filling material II are as follows: calculated by mass percentage, 23% concentrated coal slurry water, 28% coal powder slag, 15% cement, 1% additives, and the balance is mine water, and the total mass percentage content of the above substances is 100%, to prepare a nearly full coal grouting filling material with a slurry concentration of 70%.

[0083] Example 4

[0084] The method of Example 1 is followed, except that the ingredients of paste filling material I are as follows: by mass percentage, 20% coal foam, 12% concentrated coal slurry, 29% coal powder slag, 8% cement, 1% additives, and the balance is mine water, and the total mass percentage content of the above substances is 100%, to prepare a nearly full coal paste filling material with a slurry concentration of 79.5%.

[0085] The method of Example 1 is followed, except that the ingredients of grouting filling material II are as follows: by mass percentage, 22% concentrated coal slurry water, 27% coal powder slag, 14% cement, 1% additives, and the remainder is mine water, and the total mass percentage content of the above substances is 100%, to prepare a nearly full coal grouting filling material with a slurry concentration of 69%.

[0086] Example 5

[0087] The method of Example 1 is followed, except that the ingredients of paste filling material I are as follows: by mass percentage, 18% coal foam, 15% concentrated coal slurry water, 23% coal powder slag, 7% cement, 1.5% additives, and the remainder is mine water, and the total mass percentage content of the above substances is 100%, to prepare a nearly full coal paste filling material with a slurry concentration of 78%.

[0088] The method of Example 1 is followed, except that the ingredients of grouting filling material II are as follows: by mass percentage, 20% concentrated coal slurry, 26% coal powder slag, 13% cement, 1% additives, and the remainder is mine water, and the total mass percentage of the above substances is 100%, to prepare a nearly full coal grouting filling material with a slurry concentration of 68%.

[0089] Example 6

[0090] The method of Example 1 is followed, except that the ingredients of paste filling material I are as follows: by mass percentage, 15% coal foam, 25% concentrated coal slurry, 20% coal powder slag, 5% cement, 1.5% additives, and the balance is mine water, and the total mass percentage of the above substances is 100%, to prepare a nearly full coal paste filling material with a slurry concentration of 77%.

[0091] The method of Example 1 is followed, except that the ingredients of grouting filling material II are as follows: by mass percentage, 15% concentrated coal slurry, 25% coal powder slag, 10% cement, 1.5% additives, and the remainder is mine water, and the total mass percentage of the above substances is 100%, to prepare a coal slurry water cementing filling material with a slurry concentration of 68%.

[0092] Performance Testing

[0093] Laboratory performance tests of paste filling materials and grouting filling materials include fluidity and compressive strength tests. The fluidity test is in accordance with the GB / T8077-2023 test standard. The metal truncated cone circular mold used in the test has a height of 300mm, an upper diameter of 100mm, and a lower diameter of 200mm. The glass plate used has a size of 400×400×5mm.

[0094] The fluidity of the paste filling material and the grouting filling material in the above-mentioned embodiments 1-6 under different ratios was tested respectively. The fluidity test results of the paste filling material in embodiments 1-6 were 185 mm, 213 mm, 204 mm, 243 mm, 265 mm, and 240 mm, respectively. Figure 6 shown.

[0095] The fluidity test results of the grouting filling materials in Examples 1-6 were 225 mm, 233 mm, 245 mm, 273 mm, 275 mm, and 291 mm, respectively. Figure 7 shown.

[0096] In the compressive strength test, a standard cubic test block with a size of 100×100×100mm was first cast, and the test block was placed in a curing box with a temperature of 20±2℃ and a humidity of not less than 90%. The test block was demolded after 24 hours and continued to be cured for 28 days. After the curing, an electro-hydraulic servo universal testing machine was used to carry out a uniaxial compressive strength test.

[0097] The compressive strength test results of the paste filling materials in Examples 1-6 were 7.3 MPa, 6.6 MPa, 6.7 MPa, 5.9 MPa, 5.3 MPa, and 5.1 MPa, respectively. Figure 6 shown.

[0098] The compressive strength test results of the grouting filling materials in Examples 1-6 were 5.7 MPa, 5.3 MPa, 5.2 MPa, 4.6 MPa, 4.55 MPa, and 4.1 MPa, respectively. Figure 7 shown.

[0099] During on-site application, the material ratio can be selected based on the above test results and combined with actual project needs.

[0100] The laboratory performance test of the bond formed by the lump coal and the grouting filling material includes compressive strength test and tensile strength test. First, the test specimens of the bond are prepared: a number of lump coals with a particle size of about 10 cm are placed in 6 50×50×50 cm molds, and then the paste filling material slurry in Examples 1-6 is poured into them respectively, and the surface is smoothed and placed in a standard curing box for curing for 24 hours before demolding, and then curing for another 28 days after demolding. The uniaxial compressive strength is tested using an electro-hydraulic servo universal testing machine.

[0101] The compressive strength test results of the cementing bodies in Examples 1-6 were 3.2MPa, 3.5MPa, 2.2MPa, 2.6MPa, 3.0MPa, and 2.8MPa, respectively. The tensile strength test was conducted using an electro-hydraulic servo universal testing machine and was indirectly measured using the Brazilian splitting method. The tensile strength test results of the cementing bodies in Examples 1-6 were 0.52MPa, 0.81MPa, 0.69MPa, 0.48MPa, 0.61MPa, and 0.85MPa, respectively. Figure 8 shown.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine, characterized in that: The following steps are involved: S1. Obtaining physical and mechanical parameters of coal and rock layers and mining technical parameters of fully mechanized caving working face; S2. Obtain the basic characteristics of the old empty tunnel, including the cross-sectional shape, cross-sectional dimensions, tunnel length, inclination, azimuth, the distance between the roof and floor of the old empty tunnel and the roof and floor of the coal seam, the support method and parameters of the old empty tunnel, and the gas type and concentration in the old empty tunnel; S3. Determine the on-site filling method and materials for the old empty tunnels in the fully mechanized caving working face of the outburst mine: When b≥N and a≤S, the filling method is to select paste filling material and fill it by paste filling method; When b≥S and a≤M, the filling method is to select lump coal and grouting filling materials to fill by throwing and grouting combined filling method; Among them, a is the elevation of the roof of the old empty tunnel, b is the elevation of the bottom of the old empty tunnel, M is the elevation of the roof of the coal seam, N is the elevation of the bottom of the coal seam, and S is the top boundary elevation of the machine mining range of the comprehensive mining working face. The paste filling material, lump coal and grouting filling material are all made from underground raw coal and drill cuttings and coal powder slag.

2. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 1 is characterized in that: The preparation method of the paste filling material is as follows: raw coal produced by mining and tunnel excavation in the working face of the mine is sorted to separate foam coal and coal mud water with a particle size of less than 7 mm; The coal slurry is subjected to sedimentation and dehydration treatment to obtain concentrated coal slurry with a water content of 20% to 25%; Screen the drill cuttings and coal powder slag formed by drilling in the mine to remove impurities; The foamed coal, concentrated coal slurry water and coal powder slag are mixed and stirred, cement, additives and mine water are added during the stirring process, and after uniform stirring, a paste filling material with a slurry concentration of 77% to 86% is prepared.

3. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 1 is characterized in that: The preparation method of the lump coal and grouting filling material is as follows: The raw coal produced by mining and tunneling in the underground mine is sorted to separate the foamy coal and coal slime water with a particle size of 9-11cm; The coal slurry is subjected to sedimentation and dehydration treatment to obtain concentrated coal slurry with a water content of 20% to 25%; Screen the drill cuttings and coal powder slag formed by drilling in the mine to remove impurities; The concentrated coal slurry water and coal powder slag are mixed and stirred, cement, additives and mine water are added during the stirring process, and after uniform stirring, a grouting filling material with a slurry concentration of 68% to 75% is prepared.

4. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 2 is characterized in that: The paste filling method comprises the following steps: Arrange filling columns: Arrange multiple filling columns in the old empty tunnel by injecting filling materials into vertical filling bags, with the distance between adjacent filling columns being the same; Anchor withdrawal: Starting from one end of the old empty tunnel close to the cutting direction of the fully mechanized caving working face, the locks, trays, anchor nets, steel belts, etc. of the roof of the old empty tunnel and the two sides of the anchor rope are dismantled and recycled in sequence through the anchor withdrawal device; Establishment of filling body: after a single anchor withdrawal is completed, a filling body is established in the old empty tunnel within the distance range of the single anchor withdrawal by using paste filling materials until the old empty tunnel is completely filled.

5. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 4 is characterized in that: The vertical filling bag is formed by cutting off a waste wind tube in the mine with a length equal to the height of the old empty tunnel, and gluing and sealing one end opening of the wind tube with a wind tube cloth to form a vertical filling bag; The open end of the filling bag is hung on the area without anchor rods and cables on the roof of the old empty tunnel by anchor nails, and the paste filling material is injected into the upright filling bag to form a filling column. The paste filling material is pumped into the upright filling bag through the grouting hose to form a filling column, and a filling column is established at every end distance in the same way.

6. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 4 is characterized in that: Cut off the waste diameter air duct of the same length as the width of the old empty tunnel, use air duct cloth to glue and seal the opening of one end of the cut air duct, and glue the other end with air duct cloth to leave a grouting hole to form a horizontal filling bag, and place the filling bag horizontally on the bottom plate of the old empty tunnel, so that the two ends of the horizontal filling bag contact the two sides of the old empty tunnel, and use a grouting hose to pump the paste filling material into the horizontal filling bag to allow the horizontal filling bag to expand freely. When the paste filling material slurry begins to overflow from the upper grouting hole, stop grouting, close the grouting hole, and fix the two ends of the horizontal filling bag to the two sides of the tunnel with anchor nails; In the same way, a second horizontal filling bag is constructed next to the first horizontal filling bag that has been grouted. After the two filling bags are solidified, a third horizontal filling bag is constructed in the middle position above the two filling bags. The three horizontal filling bags form a filling retaining wall with a height of 0.9-1.1m. The grouting hose is used to inject paste filling material slurry into the space enclosed between the filling retaining wall and the old empty tunnel or the filling body until the slurry liquid level is flush with the top surface of the retaining wall.

7. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 3 is characterized in that: The method of combined throwing and grouting filling is specifically as follows: Divide the old empty tunnel into multiple filling sections with the same filling step length; Starting from one end of the old empty tunnel near the cutting direction of the fully mechanized caving working face, the locks, trays, anchor nets, steel belts, etc. of the roof of the old empty tunnel and the two sides of the anchor rope are dismantled and recycled in turn through the anchor withdrawer; After a single anchor withdrawal is completed, the coal blocks are first scattered in the filling single layer, and then the grouting filling material is injected into the gaps between the coal blocks until the slurry liquid level is the same as the top surface of the coal blocks. After all the slurry solidifies, the filling is completed.

8. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 7 is characterized in that: The filling section is divided into a plurality of filling areas of the same height, and the unshielded side of the filling single layer is provided with a retractable backstop; During the scattering process, the coal in the filling area is pushed, compacted and leveled by the movement of the gangue filler and the forward and backward extension of the push plate. When the thickness of the coal in the filling area reaches the requirement, the bottom of the push plate is fixed to the ground, and telescopic plates are set on both sides of the retreat plate to make the telescopic plates completely contact the two sides of the old empty tunnel.

9. The method for nearly full coal filling in an empty roadway of a fully mechanized caving working face in a protruding mine according to claim 7 is characterized in that: When filling the filling area close to the top wall of the old empty tunnel, adjust the position of the push plate so that its front is close to the upper side of the filling body below and the top is connected, and dig a groove in the top plate above the push plate, and let the mouth of the filling pipeline enter the filling space along the hole groove to realize the top filling of the filling area.

10. A nearly full coal filling material for an empty roadway in a fully mechanized caving working face of a protruding mine, characterized in that: Including paste filling materials and tube filling materials; The paste filling material comprises the following components in weight percentage: 15% to 30% of coal foam, 10% to 25% of concentrated coal slurry, 20% to 35% of coal powder slag, 5% to 15% of cement, 0.5% to 1.5% of early strength agent, and 0.5% to 1.5% of water reducing agent; The grouting filling material comprises the following components in weight percentage: 15% to 30% of concentrated coal mud water, 25% to 40% of coal powder slag, 10% to 20% of cement, 0.5% to 1.5% of early strength agent, and 0.5% to 1.5% of water reducing agent.

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