High-pressure water jet rotary cut coal unmanned mining face green mining method for large-dip-angle coal seam

Abstract

The invention discloses a high-pressure water jet rotary cut coal unmanned mining face green mining method for a large-dip-angle coal seam, which comprises the following steps: planning a working face and a coal mining unit for coal mining operation according to engineering geological data, forming a coal cutting hole and a gas drainage hole for coal mining in the planned coal mining unit, and forming a coal sliding port at the lower end of the coal mining unit; the coal mining unit is mined, and meanwhile the coal mining process and the goaf side, top and bottom conditions are monitored; carrying out coal-water separation on the mined water-coal flow; and backfilling a goaf formed after coal mining. The invention provides a brand-new green coal mining method based on multiple technologies such as unmanned mining face, high-pressure water jet rotary cutting method coal crushing, coal-water mixed gravity coal discharging, vibrating screen coal-water separation, explosion-proof unmanned aerial vehicle stope monitoring, filling type water-preserved mining, multi-unit simultaneous coal mining and the like. The problem of safe and efficient mining of various large-dip-angle coal seams is well solved.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to an unmanned face green mining method for coal seams with high-pressure water jets for whirling and shredding coal. Background Art

[0002] At present, there are corresponding coal mining methods for most inclined coal seams, but there are still certain limitations in the successful mining of some steep-angle coal seams with special occurrence conditions.

[0003] This limitation is mainly reflected in several aspects: (1) The thickness of the coal seam is relatively thin and has no economic mining value (except for the mining of the protective layer). Most coal mining enterprises abandon it and waste resources; (2) In the mining process of the "three soft" coal seams with large inclination angles, the spalling and roof collapse are very serious, making it difficult to meet the requirements of safety and efficiency at the same time, resulting in poor benefits for coal mining enterprises; (3) In the mining process of steeply inclined medium-thick and thin coal seams, the mining technology is relatively backward and difficult to achieve mechanization. It is precisely because of the existence of the above limitations that it is urgent to change the coal mining method, innovate the coal mining technology, and explore a new coal mining method that can adapt to various situations in large-angle coal seams (inclination>30°) and conform to the spirit of green mining, unmanned mining, safety and efficiency. Summary of the invention

[0004] The technical problem to be solved by the present invention is to solve the technical difficulty of safe and efficient mining of existing steep-angle coal seams, and to provide a green mining method for unmanned mining of steep-angle coal seams by high-pressure water jet rotary cutting of coal.

[0005] The present invention solves the above technical problems through the following technical solutions, and the present invention comprises the following steps:

[0006] S1, plan the working face and coal mining units of coal mining operations based on engineering geological data;

[0007] S11, planning the working face, determining the positions of the upper chute, the lower chute and the chute connecting tunnel, opening the upper chute and the lower chute along the working face, one end of the upper chute and the lower chute are respectively connected to the main transportation tunnel of the mining area, and the other end of the upper chute and the lower chute are respectively connected to the chute connecting tunnel, opening a return air shaft between the chute connecting tunnel and the surface, or opening a special return air tunnel to connect the main return air tunnel of the mining area, and opening a blind vertical shaft or a blind inclined shaft between the special return air tunnel and the chute connecting tunnel to connect the two;

[0008] S12, a working face is divided into multiple strip-type coal mining units, and the number of large groups to be mined is determined according to the coal seam conditions and the number of coal mining units. According to the principle of skip mining, the coal mining units in each large group are not adjacent to each other, and the coal mining units in the same large group are numbered with unified numbers. The coal mining units in each large group are divided into multiple small groups, and the coal mining units in each small group carry out mining operations at the same time; the optimal number of groups is 2 large groups, which can save the filling cost to the greatest extent, because the goaf formed after the coal of the last large group of coal mining units is mined does not need to be filled;

[0009] S2, opening coal cutting holes and gas extraction holes for coal mining in the planned coal mining unit, and opening a coal chute at the lower end of the coal mining unit;

[0010] S3, mining the coal mining unit and monitoring the coal mining process and the conditions of the top and bottom of the goaf;

[0011] S4, separating the mined water-coal flow into coal and water, and recycling the separated water;

[0012] S5, backfilling the goaf formed after coal mining.

[0013] In the step S11, both the upper chute and the lower chute are air intake chute, and the airflow is finally gathered at the return air shaft through the chute connecting lane, and discharged to the ground through the return air shaft;

[0014] If a return air vertical shaft is not set up, a special return air lane must be set up. A blind vertical shaft or a blind inclined shaft is set between the special return air lane and the chute connecting lane. The airflow from the upper chute and the lower chute is gathered at the blind vertical shaft or the blind inclined shaft and flows to the special return air lane through the blind vertical shaft or the blind inclined shaft, and then enters the return air lane of the mining area through the special return air lane.

[0015] In step S11, the lower drift of the previous working face is used as the upper drift of the next adjacent working face. Only the first working face needs to be provided with two drifts, and the subsequent working faces only need to be provided with one drift. The lower drift of the previous working face can be used as the upper drift of the next working face.

[0016] The return air vertical shaft or special return air lane and the blind vertical shaft or blind inclined shaft are not only used as the return air channel of the current working face, but also continue to be used as the special return air channel of the next working face. It is only necessary to connect the longitudinal connecting lanes of the upper and lower working faces with each other, and the airflow will naturally flow to the return air vertical shaft and discharge to the surface, or flow to the blind vertical shaft or blind inclined shaft and enter the return air lane of the mining area through the special return air lane.

[0017] In the step S11, the large-diameter return air shaft between the chute connecting tunnel and the ground may also be replaced by a number of small-diameter vertical air ducts directly to the ground.

[0018] The process of setting the coal cutting hole and the gas extraction hole in step S2 is as follows:

[0019] Step S21, determining the opening position and opening diameter of the coal cutting hole on the cross section of the coal mining unit according to the coal seam thickness and the width of the coal mining unit, the cut-off position of the coal cutting hole is located at the coal chute at the lower end of the coal mining unit, that is, the coal cutting hole is connected to the coal chute, and the coal cutting hole is parallel to the axis of the coal mining unit. According to the determined opening position of the coal cutting hole in the coal mining unit, the opening cut-off position and the parallel relationship between the coal cutting hole and the axis of the coal mining unit, a drilling device is used to drill the coal cutting hole in the coal mining unit, and at the same time, the specifications of the casing placed in the coal cutting hole are determined;

[0020] Step S22, after the coal cutting hole is formed, casings are connected and lowered one by one from the upper end of the coal cutting hole until they are lowered to the bottom end of the coal cutting hole, i.e., the coal chute;

[0021] Step S23, after the casing is in place, the casing is fixed at the upper port;

[0022] Step S24, determining the opening position and opening diameter of the gas extraction hole on the cross section of the coal mining unit according to the coal seam thickness and the width of the coal mining unit, the cut-off position of the gas extraction hole is located at the coal chute at the lower end of the coal mining unit, that is, the gas extraction hole is connected to the coal chute; the gas extraction hole is parallel to the axis of the coal mining unit, and according to the determined opening position and opening cut-off position of the gas extraction hole on the coal mining unit and the parallel relationship between the gas extraction hole and the axis of the coal mining unit, a gas extraction hole is drilled in the coal mining unit, and the specifications of the steel screen pipe placed in the gas extraction hole are determined;

[0023] Step S25, after the gas extraction hole is formed, steel screen pipes are connected and lowered one by one from the upper end of the gas extraction hole until they are lowered to the bottom end of the gas extraction hole, i.e., the coal chute;

[0024] Step S26, after the steel screen pipe is in place, the steel screen pipe is fixed at the upper port.

[0025] The process of setting the coal chute in step S2 is as follows:

[0026] Step S27, a coal chute connected to the lower drift is excavated between the bottom of the coal mining unit and the lower drift, and the bottom plate of the coal chute is at the same elevation as the bottom plate of the lower drift;

[0027] Step S28, using anchor net cable spraying support method to support the top of the coal chute;

[0028] Step S29, a coal receiving chute is arranged in the coal chute, the upper end of the coal receiving chute is arranged below the lower end of the coal mining unit, and the inclination angle of the coal receiving chute is smaller than the inclination angle of the coal seam floor.

[0029] The coal receiving chute includes a chute bottom plate, a coal baffle plate and column legs. The coal baffle plates are welded on both sides of the chute bottom plate. The chute bottom plate is inclined at an angle of 15°-30°. The high end of the chute bottom plate is close to the lower port of the coal mining unit and lower than the lower edge of the lower port of the coal mining unit. The chute bottom plate is trapezoidal, the short bottom side of the trapezoid is close to the lower chute, and the long bottom side of the trapezoid is close to the coal mining unit. The column legs are fixed under the chute bottom plate.

[0030] In step S3, the mining process of the coal mining unit is as follows:

[0031] Step S31, connecting a cutting gun for coal mining to a high-pressure water-supply drill pipe, and lowering the cutting gun along the casing to the end of the casing through a drilling device;

[0032] Step S32, after the cutting gun is lowered into place with the drilling device, a set of high-pressure water rotary joints is added between the drilling device and the high-pressure water supply drill pipe, the high-pressure water rotary joint is connected to the high-pressure water pump, the high-pressure water pump works, the water outlet of the cutting gun sprays a high-pressure water jet, the drilling device drives the cutting gun to rotate, and the cutting gun starts to rotate to cut and crush coal through the high-pressure water jet;

[0033] Step S33, the cutting gun rotates under the drive of the drilling device, and retreats along the casing at a set time interval. As the cutting gun rotates and retreats, the cutting gun performs high-pressure water jet rotary retreat type coal mining. Under the action of the high-pressure water jet, the casing is quickly cut, and the coal seam around the casing is cut and falls down and forms a water-coal flow under the action of the water flow to flow to the coal chute;

[0034] Step S34, using a small mining drone to monitor the high-pressure water jet whirling coal shredding process, the surrounding rock conditions of the goaf, the flow of water and coal, and whether there is clogging in the goaf floor.

[0035] The coal-water separation process of the water-coal flow in step S4 is as follows:

[0036] Step S41, a coal receiving chute is arranged in the coal chute, a scraper, a vertical elevator, a dewatering vibrating screen, a belt conveyor and a water spout are arranged in the lower chute, one end of the coal receiving chute is close to the lower port of the coal mining unit, and the other end is overlapped with the scraper; one end of the scraper is located below the coal receiving chute, and the other end is close to one side of the lower end of the vertical elevator; the vertical elevator is close to the belt conveyor, and the upper end lateral part of the vertical elevator is located above the dewatering vibrating screen; the dewatering vibrating screen is located above the belt conveyor, and the water spout is arranged between the dewatering vibrating screen and the belt conveyor;

[0037] Step S42, the broken coal cut by the cutting gun is mixed with water to form a water-coal flow, which flows out of the coal mining unit and is buffered by the coal receiving chute before falling on the scraper, which directly delivers the transferred water-coal flow to the vertical elevator, which delivers the water-coal flow to the dewatering vibrating screen arranged above the belt conveyor;

[0038] Step S43, the water-coal flow enters the dewatering vibrating screen and is dehydrated. The dehydrated crushed coal falls directly on the belt conveyor and is sent away. The separated water falls directly on the water dripping plate from the bottom of the dewatering vibrating screen, is guided to one side of the belt conveyor through the water dripping plate, and finally flows into the ditch on the other side of the downstream chute.

[0039] The process of filling the goaf in step S5 is as follows:

[0040] Step S51, using steel plates and I-beams to make a grid-shaped guard plate, and using a single pillar to support it, so that the guard plate is close to the outer wall of the coal chute, that is, one side of the lower chute;

[0041] Step S52, inserting a grouting pipe into the guard plate at the upper edge of the coal chute to monitor whether the coal chute has been filled densely during the grouting process;

[0042] Step S53, using inorganic grouting material to fill the coal chute, the filling material is poured in from the upper port of the coal mining unit, and the filling material flows down along the inclined bottom plate to the coal chute;

[0043] Step S54, the filling material of the coal chute reaches 20MPa before the goaf filling can be implemented. At the end of each continuous filling, the steel screen pipe must be quickly flushed and dredged to facilitate the steel screen pipe to extract gas.

[0044] Compared with the prior art, the present invention has the following advantages: the present invention is based on unmanned mining (safety), high-pressure water jet rotary cutting method for coal crushing (advanced technology), coal-water mixing to form water-coal flow gravity coal discharge (safety and efficiency), vibrating screen coal-water separation (automation), mining site monitoring by explosion-proof drones (artificial intelligence, safety and efficiency), filling-type water-retaining mining (green and environmentally friendly), multi-unit simultaneous coal mining (high efficiency), minimal mining impact (safety), the minimum width of the safety coal pillar in the main lane of the mining area can be reduced to zero (non-renewable resource conservation), and the remaining working faces in the same mining area other than the first working face only need to open up a drift and One connecting tunnel (low cost, high efficiency), no need for heavy equipment such as hydraulic supports and coal cutters (reducing costs, greatly reducing working face preparation time, safety), the greater the coal seam inclination, the higher the coal mining efficiency (completely changing the current situation of difficult mining of large-angle and steeply inclined coal seams), zero ground settlement (ground environment and ecology are protected), all equipment involved are easy to realize artificial intelligence control (intelligent mine), various faults in the working face will not seriously affect the normal mining of the working face, etc., a new green coal mining method is proposed, which better solves the problem of safe and efficient mining of various inclined coal seams;

[0045] In the present invention, a high-pressure water jet is ejected from a water outlet of the cutting gun, and the operation of the drilling device drives the cutting gun to rotate. The cutting gun starts to rotate and cut coal and crush coal through the high-pressure water jet. The cutting gun rotates at a certain speed driven by the drilling device, and retreats along the casing at a set time interval. As the cutting gun rotates and retreats, the cutting gun performs high-pressure water jet rotary retreat type coal mining. Under the action of the high-pressure water jet, the casing is quickly cut, and the coal seam within a certain range around the casing is cut and falls down, and forms a water-coal flow under the action of the water flow and quickly flows to the coal chute, thereby realizing safe and low-cost mining of the coal seam with a large dip angle.

[0046] In the present invention, the number of coal mining units and the width of coal mining units that can be planned in the working face are determined by using engineering geological data, and the coal mining units are grouped into large groups according to the principle of skip mining, and the large groups are further grouped into small groups. The small groups are sorted and implemented for small group mining, and the coal mining units in one group are mined simultaneously each time. The optimal number of large groups is 2. When the coal mining units are divided into only 2 large groups, 50% of the goaf does not need to be filled, and the filling cost can be greatly reduced.

[0047] In the present invention, the lower drift of the upper working face is used as the upper drift of the adjacent next working face, which reduces the development work of the drift and lowers the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the spatial layout of the coal mining face (return air shaft);

[0049] Figure 2 It is a schematic diagram of the spatial layout of the coal mining face (dedicated return air lane, blind shaft);

[0050] Figure 3 It is a schematic diagram of the layout of the coal mining face (return air shaft);

[0051] Figure 4 It is a schematic diagram of the layout of the coal mining face (dedicated return air lane, blind shaft);

[0052] Figure 5 This is a schematic diagram of return air shaft sharing;

[0053] Figure 6 This is a schematic diagram of the shared use of dedicated return air lanes and concealed shafts;

[0054] Figure 7 It is the location diagram of the coal cutting holes and gas extraction holes on the cross section of the coal mining unit;

[0055] Figure 8 It is a schematic diagram of gas extraction during coal mining;

[0056] Fig. 9 It is a schematic diagram of gas extraction during filling;

[0057] Fig.10 It is a schematic diagram of the coal cutting, gas extraction, water-coal flow conveying, dehydration, and dehydrated coal transportation system;

[0058] Fig.11 This is a schematic diagram of the structure of the coal chute. Fig.11 a is a top view of the coal chute. Fig.11 b is the left view of the coal receiving chute;

[0059] Fig.12 This is a schematic diagram of the cutting gun structure. Fig.12 a is a three-dimensional diagram of a cutting gun. Fig.12 b is a cross-sectional view of the cutting gun;

[0060] Fig.13 It is a work flow chart of the present invention. DETAILED DESCRIPTION

[0061] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0062] This embodiment is explained in detail by taking the 11802 working face of Juxin Coal Mine as an implementation case. The coal seam involved in the working face of this embodiment is the 18# coal seam with an average thickness of 2.8m. The roof is siltstone or mudstone, and the bottom plate is mainly mudstone, followed by siltstone. The mechanical strength of siltstone is medium, while the mechanical strength of mudstone is low and the stability is poor.

[0063] In this embodiment, the inclination of the 18# coal seam is 32-36°, with an average inclination of 34° (up to 50° in some areas), the coal seam is relatively stable, and the Proctor hardness coefficient of the coal is f=0.3, which is a mineable coal seam in the entire area.

[0064] In this embodiment, the mining length of the working face is 855m, the width of the coal mining unit 061 is 5m, and the number of coal mining units 061 is 171 in total.

[0065] The mining process of this embodiment is as follows Fig.13 As shown:

[0066] S1, based on the existing engineering geological data, plan the working face and coal mining unit 061 of the coal mining operation;

[0067] S11, planning the working face, determining the positions of the upper chute 021, the lower chute 022 and the chute connecting tunnel 023, opening the upper chute 021 and the lower chute 022 along the working face, one end of the upper chute 021 and the lower chute 022 are respectively connected to the mining area transportation tunnel 02, the other end of the upper chute 021 and the lower chute 022 are respectively connected to the chute connecting tunnel 023, opening a return air shaft 03 between the chute connecting tunnel 023 and the ground surface 01, or opening a special return air shaft 024 to connect to the mining area return air tunnel 07, and opening a blind vertical shaft 025 or a blind inclined shaft between the special return air shaft 024 and the chute connecting tunnel 023 to connect the two;

[0068] like Figure 1 and 2 As shown, the gray block in the figure is the black coal seam 06 (the same below). In this embodiment, the upper chute 021 and the lower chute 022 are both air intake chute, and the air flow finally converges at the dark shaft 025 through the chute connecting tunnel 023, and flows to the mining area return air tunnel 07 through the dedicated return air tunnel 024;

[0069] Design the cross-sectional shape, size, support method and support parameters of upper drift 021, lower drift 022, drift connecting tunnel 023, special return air tunnel 024 and blind shaft 025 between special return air tunnel 024 and upper and lower drift connecting tunnels. According to the mechanical properties of coal seam 06, coal seam 06 roof, coal seam 06 floor and the properties of ground stress field, apply "elastic-plastic theory" to check the strength of the roof of coal mining unit 061, the safety coal pillar 04 of the drift connecting tunnel, the safety coal pillar 05 of the mining area transportation tunnel, and the support of the tunnel, and make corresponding adjustments to the width of coal mining unit 061, the width of the safety coal pillar 04 of the drift connecting tunnel, the width of the safety coal pillar 05 of the mining area transportation tunnel, and the tunnel support parameters based on the check results.

[0070] S12, in this embodiment, the 11802 working face is divided into 171 coal mining units 061, each coal mining unit 061 is 5m wide and is divided into 2 large groups, such as Figure 3 and Figure 4 As shown. The coal mining unit 061 in the first group is marked with ①, and the coal mining unit 061 in the second group is marked with ②. The first group is mined first, and after the first group is mined, the second group is mined; the units in the first group that have been mined must be filled immediately, and after the mining of the second group of coal mining units 061 is completed, the upper and lower ends of the coal mining units 061 must be sealed, and the seal must be tight, and there must be no gas leakage gaps. The coal mining units 061 in each group need to be divided into several small groups again, and then a mining sequence is determined.

[0071] The lower chute 022 of the previous working face is used as the upper chute 021 of the next adjacent working face. Only the first working face needs to be provided with two chute, and the subsequent working faces only need to be provided with one chute. The lower chute 022 of the previous working face can be used as the upper chute 021 of the next working face.

[0072] The dedicated return air lane 024 and the dark shaft 025 are not only used as the dedicated return air channel of the current working face, but also continue to be used as the dedicated return air channel of the next working face. Figure 5 and 6 As shown. When the previous working face is mined and filled, the junction between the mining area transportation tunnel 02 and the upper chute 021 of the previous working face and the upper side of the blind shaft 025 in the chute connecting tunnel 023 are closed with closed walls 026. Then the dedicated return air tunnel 024 and the blind shaft 025 naturally become the dedicated return air ducts of the next working face. The wind from the upper chute 021 and the lower chute 022 of the next working face can flow to the mining area return air tunnel 07 through the blind shaft 025 and the dedicated return air tunnel 024. Therefore Figure 2 The dedicated return air lane 024 and the concealed shaft 025 can also serve as dedicated return air ducts for the next working face and several subsequent working faces.

[0073] S2, a coal cutting hole 10 and a gas extraction hole 11 for coal mining are opened in the planned coal mining unit 061, and a coal chute 12 is opened at the lower end of the coal mining unit 061; the specific process is as follows:

[0074] Step S21, determining the opening position and opening diameter of the coal cutting hole 10 on the cross section of the coal mining unit 061 according to the thickness of the coal seam 06 and the width of the coal mining unit 061, the closing position of the coal cutting hole 10 is located at the coal chute 12 at the lower end of the coal mining unit 061, that is, the coal cutting hole 10 is connected to the coal chute 12, and the coal cutting hole 10 is parallel to the axis of the coal mining unit 061. Using the determined opening position of the coal cutting hole 10 in the coal mining unit 061, the closing position of the coal cutting hole 10, and the parallel relationship between the coal cutting hole 10 and the axis of the coal mining unit 061, the coal cutting hole 10 is drilled in the coal mining unit 061, and the specifications of the casing placed in the coal cutting hole 10 are determined;

[0075] The position of the coal cutting hole 10 in the cross section of the coal mining unit 061 is on the vertical symmetry line of the cross section of the coal mining unit 061 and below the horizontal symmetry line of the cross section of the coal mining unit 061. The gas extraction hole 11 is on one side (left or right) of the vertical symmetry line of the cross section of the coal mining unit 061 and above the horizontal symmetry line of the cross section of the coal mining unit 061. Figure 7As shown in the figure, h is the height of the coal mining unit 061, and a is the width of the coal mining unit 061. A casing made of PVC or glass fiber reinforced plastic is arranged in the coal cutting hole 10, the gas extraction hole 11 also serves as a coal flushing hole, and a steel screen pipe 13 is built in. Many circular holes for ventilation are drilled on the pipe wall of the steel screen pipe 13 along the longitudinal direction of the steel screen pipe 13 at a certain interval, and the diameter of the circular hole is 15mm.

[0076] Step S22, after the coal cutting hole 10 is formed, casings are connected and lowered one by one from the upper end of the coal cutting hole 10 until they are lowered to the bottom end of the coal cutting hole 10, that is, the coal chute 12;

[0077] Step S23, after the casing is in place, the casing is fixed at the upper port;

[0078] Step S24, according to the thickness of the coal seam 06, the opening position and opening diameter of the gas extraction hole 11 on the cross section of the coal mining unit 061 are determined, the cut-off position of the gas extraction hole 11 is located at the coal chute 12 at the lower end of the coal mining unit 061, that is, the gas extraction hole 11 is connected to the coal chute 12; the gas extraction hole 11 is parallel to the axis of the coal mining unit 061, and the gas extraction hole 11 is drilled in the coal mining unit 061 by using the determined opening position of the gas extraction hole 11 on the coal mining unit 061, the cut-off position of the gas extraction hole 11, and the parallel relationship between the axis of the gas extraction hole 11 and the coal mining unit 061, and at the same time, the specifications of the steel screen pipe 13 placed in the gas extraction hole 11 are determined;

[0079] Step S25, after the gas extraction hole 11 is formed, the steel screen pipes 13 are connected and lowered one by one from the upper end of the gas extraction hole 11 until they are lowered to the bottom end of the gas extraction hole 11, that is, the coal chute 12;

[0080] Step S26, after the steel screen pipe 13 is placed in place, the steel screen pipe 13 is fixed at the upper end.

[0081] like Figure 8 and Fig. 9 As shown, gas is extracted during coal mining and filling, and the gas extracted in the figure is a mixture of gas and air 30. The upper end of the steel screen pipe 13 is connected to the negative pressure gas extraction pipe 132 and the high pressure water pipe 133 through a tee 131, and each is controlled by a valve.

[0082] The process of setting the coal chute 12 in step S2 is as follows:

[0083] Step S27, as Fig.10As shown, a coal chute 12 connected to the lower drift 022 is excavated between the bottom of the coal mining unit 061 and the lower drift 022. The bottom plate of the coal chute 12 and the bottom plate of the lower drift 022 are at the same horizontal elevation. The width of the coal chute 12 is 1.5m smaller than the width of the coal mining unit 061. The height of the coal chute 12 is 2.5m and the depth of the coal chute 12 is 2m.

[0084] Step S28, using anchor net cable spraying support to support the top of the coal chute 12;

[0085] Step S29, a coal receiving chute 14 is arranged in the coal chute 12, the upper end of the coal receiving chute 14 is arranged below the lower end of the coal mining unit 061, and the inclination angle of the coal receiving chute 14 is smaller than the inclination angle of the bottom plate of the coal seam 06.

[0086] like Fig.11 As shown, the coal receiving chute 14 includes a chute bottom plate 141, a coal blocking plate 142 and a column leg 143. The coal blocking plate 142 is welded to both sides of the chute bottom plate 141. The chute bottom plate 141 is tilted with an inclination angle of 20°. The high end of the chute bottom plate 141 is close to the coal mining unit 061. The chute bottom plate 141 is trapezoidal, the short bottom side of the trapezoid is close to the lower chute 022, and the long bottom side of the trapezoid is close to the coal mining unit 061. The column leg 143 is fixed under the chute bottom plate 141.

[0087] The short bottom side of the trapezoidal chute bottom plate 141 is 1500mm long, the long bottom side is 2500mm long, the height near the coal mining unit 061 is 1200mm, the height near the lower chute 022 is 500mm, the chute bottom plate 141 is supported by a steel plate with a thickness of not less than 10mm, and the coal retaining plate 142 is 300mm high and 8mm thick. There are five column legs 143 of the coal receiving chute 14, which are round steel pipes with an outer diameter of 150mm and a wall thickness of 8mm. One column leg 143 is set at the centroid of the chute bottom plate 141.

[0088] S3, mining unit 061, and using small mining drones to monitor the mining process and the top and bottom conditions of goaf 08;

[0089] The mining process of coal mining unit 061 is as follows:

[0090] Step S31, the cutting gun 15 for coal mining is connected to the drilling device 09 through the high-pressure water supply drill rod 151, a high-pressure water rotary joint 152 is added between the drilling device 09 and the high-pressure water supply drill rod 151, and the high-pressure water rotary joint 152 is connected to the high-pressure water pump 153 through a high-pressure water pipe 154;

[0091] In step S32, the rotation of the cutting gun is driven by the high-pressure water supply drill rod 151. The rotation of the high-pressure water supply drill rod 151 originates from the drilling device 09, but the high-pressure water rotary joint 152 does not drill with the high-pressure water supply drill rod 151. Therefore, while the high-pressure water supply drill rod 151 rotates, the high-pressure water pump 153 can continuously supply high-pressure water to the high-pressure water supply drill rod 151 through the high-pressure water connecting pipe and the high-pressure water rotary joint 152, and finally emits a high-pressure water jet through the water spray hole of the cutting gun 15 to cut and crush the coal.

[0092] Step S33, the cutting gun 15 rotates under the drive of the drilling device 09, and retreats along the casing at a set time interval. As the cutting gun 15 rotates and retreats, the cutting gun 15 performs high-pressure water jet rotary retreat type coal mining. Under the action of the high-pressure water jet, the casing is quickly cut, and the coal seam 06 around the casing is shredded and falls down, and forms a water-coal flow under the action of the water flow and flows to the coal chute 12;

[0093] Step S34, using a small mining drone to monitor various goaf 08 conditions such as the high-pressure water jet whirling coal shredding process, the surrounding rock conditions of the goaf 08, the flow of water and coal, and whether there is siltation on the bottom plate of the goaf 08.

[0094] In this embodiment, the number of water spray holes on the cutting gun 15 for spraying high-pressure water jets is 8, and 4 rows are arranged; 2 holes in each row are arranged on the radial line, and the positions differ by 180°; the axes of the 4 water spray holes in the first row and the fourth row are perpendicular to the axis of the cutting gun, the axis of the second row of holes is at an angle of 70° to the axis of the cutting gun, and the angle is toward the front end of the cutting gun; the angle between the 2 water spray holes in the third row and the axis of the cutting gun is 80°, and the angle is toward the front end of the cutting gun. The structure of the cutting gun 15 is as follows: Fig.12 shown.

[0095] In this embodiment, the water pressure generated by the high-pressure water pump 153 is 25MPa, and the rotation speed of the drilling device 09 is 40 rpm; along the axial direction of the coal mining unit 061, the length of the coal cut by the cutting gun 15 each time is 1000mm; the distance that the cutting gun 15 retreats along the axial direction of the coal mining unit 061 each time is 1000mm; along the axial direction of the coal mining unit 061, the time for the cutting gun 15 to cut coal at a fixed position is 35min.

[0096] In this embodiment, the small mining drone has a water fog resistance function. In addition to normal high-definition video, its camera also needs to have an infrared video function to ensure that it can monitor the status of the goaf 08 and the coal cutting situation of the cutting gun 15 when the water fog is dense.

[0097] S4, separating the mined water-coal flow into coal and water;

[0098] The coal-water separation process of the water-coal flow is as follows:

[0099] Step S41, the coal receiving chute 14 is arranged in the coal chute 12, and the scraper 16, the vertical elevator 17, the dewatering vibrating screen 19, the belt conveyor 18 and the water-shedding plate 20 are arranged in the lower chute 022, one end of the coal receiving chute 14 is close to the lower port of the coal mining unit 061, and the other end overlaps the scraper 16; one end of the scraper 16 is located below the coal receiving chute 14, and the other end is close to the lower end side of the vertical elevator 17; the vertical elevator 17 is close to the belt conveyor 18, and the upper end lateral part of the vertical elevator 17 is located above the dewatering vibrating screen 19; the dewatering vibrating screen 19 is located above the belt conveyor 18, and the water-shedding plate 20 is arranged between the dewatering vibrating screen 19 and the belt conveyor 18;

[0100] The bottom plate of the lower chute 022 is provided with a slight slope in the horizontal direction with an angle of 2°-3°. The bottom plate of the lower chute 022 on the side of the ditch 21 is lower, and the bottom plate of the lower chute 022 on the side of the belt conveyor 18 is higher. The purpose is to guide the water removed from the dewatering vibrating screen 19 into the ditch 21, and then flow to the sedimentation tank for sedimentation, and then be used again for cutting coal with the cutting gun 15, so as to realize the recycling of water.

[0101] Step S42, the broken coal cut by the cutting gun 15 is mixed with water to form a water-coal flow, which flows out of the coal mining unit 061 and is buffered by the coal receiving chute 14 before falling on the scraper 16, and the scraper 16 directly sends the transferred water-coal flow to the vertical elevator 17, and the vertical elevator 17 transfers the water-coal flow to the dewatering vibrating screen 19 arranged above the belt conveyor 18;

[0102] In step S43, the water-coal flow enters the dehydration vibrating screen 19 and is dehydrated. The dehydrated crushed coal falls directly onto the belt conveyor 18, and the dehydrated water falls directly onto the water dripping plate 20 from the bottom of the dehydration vibrating screen 19, flows to the outside of the belt conveyor 18 through the water dripping plate 20, and finally flows into the ditch 21 on the other side.

[0103] The scraper 16 of this embodiment can be a single scraper 16, or two scrapers 16 can be placed side by side to form a combined scraper 16 for use; the width of the feed port of the vertical elevator 17 is greater than the width of the scraper 16; the capacity of the belt conveyor 18 to transport goods is greater than the dehydration and transportation capacity of the dehydration vibrating screen 19, the dehydration and transportation capacity of the dehydration vibrating screen 19 is greater than the lifting capacity of the vertical elevator 17, the lifting capacity of the vertical elevator 17 is greater than the transportation capacity of the scraper conveyor, and the transportation capacity of the scraper conveyor is greater than the transfer capacity of the coal receiving chute 14.

[0104] S5, backfilling the goaf 08 formed after coal mining, the specific process is as follows:

[0105] Step S51, using a 6mm thick steel plate in combination with an I-beam to make a tic-tac-toe guard plate, and using a single pillar for support, so that the guard plate is close to the outer wall of the coal chute 12, that is, one side of the lower chute 022, and the guard plate should have a high lateral pressure resistance to prevent the coal chute 12 from exploding during the filling process;

[0106] Step S52, inserting a slurry return pipe on the guard plate at the upper edge of the coal chute 12 to monitor whether the coal chute 12 has been filled densely, and the slurry return pipe is an iron pipe or a PVC pipe;

[0107] Step S53, using inorganic grouting material to fill the coal chute 12, the filling material is poured in from the upper port of the coal mining unit 061, and the filling material flows down along the inclined bottom plate of the goaf 08 of the coal mining unit 061 to the coal chute 12;

[0108] Step S54, the filling material of the coal chute 12 reaches 20MPa before the goaf 08 can be filled. At the end of each continuous filling, the steel screen pipe 13 must be quickly flushed and dredged to prevent the steel screen pipe 13 from being blocked and to facilitate the steel screen pipe 13 to extract gas.

[0109] The grouting material used for filling the coal chute 12 and the grouting material used in the 10m area of ​​goaf 08 near the coal chute 12 are different from the grouting materials used in the other goaf 08. The grouting material used for filling the coal chute 12 and the grouting material used in the 10m area of ​​goaf 08 near the coal chute 12 need to have high-strength fast-setting function, and the 24-hour compressive strength should be above 20MPa, so as to meet the requirements of timely, rapid and continuous filling of the subsequent goaf 08;

[0110] In order to prevent the occurrence of explosion accidents of the guard plate, the grouting material used for filling the coal chute 12 and the filling of the 10m area of ​​the goaf 08 close to the coal chute 12 can be divided into 2-3 fillings; the 28-day uniaxial compressive strength of the inorganic slurry must be higher than the uniaxial compressive strength of the coal body.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An unmanned green mining method for coal seams with high-pressure water jets for whirling and shredding coal, characterized in that: The following steps are involved: S1, plan the working face and coal mining units of coal mining operations based on engineering geological data; S11, planning the working face, determining the positions of the upper chute, the lower chute and the chute connecting tunnel, opening the upper chute and the lower chute along the working face, one end of the upper chute and the lower chute are respectively connected to the main transportation tunnel of the mining area, and the other end of the upper chute and the lower chute are respectively connected to the chute connecting tunnel, opening a return air shaft between the chute connecting tunnel and the surface, or opening a special return air tunnel to connect the main return air tunnel of the mining area, and opening a blind vertical shaft or a blind inclined shaft between the special return air tunnel and the chute connecting tunnel to connect the two; S12, a working face is divided into a plurality of strip-type coal mining units, and the number of large groups to be mined is determined according to the coal seam conditions and the number of coal mining units. According to the principle of skip mining, the coal mining units in each large group are not adjacent to each other, and the coal mining units in the same large group are numbered with unified numbers. The coal mining units in each large group are divided into a plurality of small groups, and the coal mining units in each small group carry out mining operations at the same time; S2, opening coal cutting holes and gas extraction holes for coal mining in the planned coal mining unit, and opening a coal chute at the lower end of the coal mining unit; S3, mining the coal mining unit and monitoring the coal mining process and the conditions of the top and bottom of the goaf; S4, separating the mined water-coal flow into coal and water, and recycling the separated water; S5, backfilling the goaf formed after coal mining.

2. The green mining method for high-inclination coal seam high-pressure water jet cyclone shredding coal without human face according to claim 1 is characterized in that: In the step S11, both the upper chute and the lower chute are air intake chute, and the airflow is finally gathered at the return air shaft through the chute connecting lane, and discharged to the ground through the return air shaft; If a return air vertical shaft is not set up, a special return air lane must be set up. A blind vertical shaft or a blind inclined shaft is set between the special return air lane and the chute connecting lane. The airflow from the upper chute and the lower chute is gathered at the blind vertical shaft or the blind inclined shaft and flows to the special return air lane through the blind vertical shaft or the blind inclined shaft, and then enters the return air lane of the mining area through the special return air lane.

3. The green mining method for high-inclination coal seam high-pressure water jet cyclone shredding coal without human face according to claim 1 is characterized in that: In step S11, the lower drift of the previous working face is used as the upper drift of the next adjacent working face. Only the first working face needs to be provided with two drifts, and the subsequent working faces only need to be provided with one drift. The lower drift of the previous working face can be used as the upper drift of the next working face. The return air vertical shaft or special return air lane and blind vertical shaft are not only used as the return air channel of the current working face, but also continue to be used as the special return air channel of the next working face. It is only necessary to connect the longitudinal connecting lanes of the upper and lower working faces with each other, and the airflow will naturally flow to the return air vertical shaft and discharge to the surface, or flow to the blind vertical shaft, blind inclined shaft and enter the return air lane of the mining area through the special return air lane.

4. The green mining method for high-inclination coal seam high-pressure water jet cyclone shredding coal without human face according to claim 1 is characterized in that: In the step S11, the large-diameter return air shaft between the chute connecting tunnel and the ground is replaced by a number of small-diameter vertical air ducts directly to the ground.

5. The green mining method for high-inclination coal seam high-pressure water jet cyclone shredding coal without human face according to claim 1 is characterized in that: The process of setting the coal cutting hole and the gas extraction hole in step S2 is as follows: Step S21, determining the opening position and opening diameter of the coal cutting hole on the cross section of the coal mining unit according to the coal seam thickness and the width of the coal mining unit, the cut-off position of the coal cutting hole is located at the coal chute at the lower end of the coal mining unit, that is, the coal cutting hole is connected to the coal chute, and the coal cutting hole is parallel to the axis of the coal mining unit. According to the determined opening position of the coal cutting hole in the coal mining unit, the opening cut-off position and the parallel relationship between the coal cutting hole and the axis of the coal mining unit, a drilling device is used to drill the coal cutting hole in the coal mining unit, and at the same time, the specifications of the casing placed in the coal cutting hole are determined; Step S22, after the coal cutting hole is formed, casings are connected and lowered one by one from the upper end of the coal cutting hole until they are lowered to the bottom end of the coal cutting hole, i.e., the coal chute; Step S23, after the casing is in place, the casing is fixed at the upper port; Step S24, determining the opening position and opening diameter of the gas extraction hole on the cross section of the coal mining unit according to the coal seam thickness and the width of the coal mining unit, the cut-off position of the gas extraction hole is located at the coal chute at the lower end of the coal mining unit, that is, the gas extraction hole is connected to the coal chute; the gas extraction hole is parallel to the axis of the coal mining unit, and according to the determined opening position and opening cut-off position of the gas extraction hole on the coal mining unit and the parallel relationship between the gas extraction hole and the axis of the coal mining unit, a gas extraction hole is drilled in the coal mining unit, and the specifications of the steel screen pipe placed in the gas extraction hole are determined; Step S25, after the gas extraction hole is formed, steel screen pipes are connected and lowered one by one from the upper end of the gas extraction hole until they are lowered to the bottom end of the gas extraction hole, i.e., the coal chute; Step S26, after the steel screen pipe is in place, the steel screen pipe is fixed at the upper port.

6. The green mining method for high-inclination coal seam high-pressure water jet cyclone shredding coal without human face according to claim 5, characterized in that: The process of setting the coal chute in step S2 is as follows: Step S27, a coal chute connected to the lower drift is excavated between the bottom of the coal mining unit and the lower drift, and the bottom plate of the coal chute is at the same elevation as the bottom plate of the lower drift; Step S28, using anchor net cable spraying support method to support the top of the coal chute; Step S29, a coal receiving chute is arranged in the coal chute, the upper end of the coal receiving chute is arranged below the lower end of the coal mining unit, and the inclination angle of the coal receiving chute is smaller than the inclination angle of the coal seam floor.

7. The green mining method for high-inclination coal seam high-pressure water jet cyclone shredding coal without human mining face according to claim 6, characterized in that: The coal receiving chute includes a chute bottom plate, a coal baffle plate and column legs. The coal baffle plates are welded on both sides of the chute bottom plate. The chute bottom plate is inclined at an angle of 15°-30°. The high end of the chute bottom plate is close to the lower port of the coal mining unit and lower than the lower edge of the lower port of the coal mining unit. The chute bottom plate is trapezoidal, the short bottom side of the trapezoid is close to the lower chute, and the long bottom side of the trapezoid is close to the coal mining unit. The column legs are fixed under the chute bottom plate.

8. The method for unmanned face-less green mining of steeply inclined coal seams with high-pressure water jet gyratory shredding of coal according to claim 5 is characterized in that: In step S3, the mining process of the coal mining unit is as follows: Step S31, connecting a cutting gun for coal mining to a high-pressure water-supply drill pipe, and lowering the cutting gun along the casing to the end of the casing through a drilling device; Step S32, after the cutting gun is lowered into place with the drilling device, a set of high-pressure water rotary joints is added between the drilling device and the high-pressure water supply drill pipe, the high-pressure water rotary joint is connected to the high-pressure water pump, the high-pressure water pump works, the water outlet of the cutting gun sprays a high-pressure water jet, the drilling device drives the cutting gun to rotate, and the cutting gun starts to rotate to cut and crush coal through the high-pressure water jet; Step S33, the cutting gun rotates under the drive of the drilling device, and retreats along the casing at a set time interval. As the cutting gun rotates and retreats, the cutting gun performs high-pressure water jet rotary retreat type coal mining. Under the action of the high-pressure water jet, the casing is quickly cut, and the coal seam around the casing is cut and falls down and forms a water-coal flow under the action of the water flow to flow to the coal chute; Step S34, using a small mining drone to monitor the high-pressure water jet whirling coal shredding process, the surrounding rock conditions of the goaf, the flow of water and coal, and whether there is clogging of the goaf floor.

9. The method for unmanned face-less green mining of steeply inclined coal seams with high-pressure water jet gyratory shredding of coal according to claim 8 is characterized in that: The coal-water separation process of the water-coal flow in step S4 is as follows: Step S41, a coal receiving chute is arranged in the coal chute, a scraper, a vertical elevator, a dewatering vibrating screen, a belt conveyor and a water spout are arranged in the lower chute, one end of the coal receiving chute is close to the lower port of the coal mining unit, and the other end is overlapped with the scraper; one end of the scraper is located below the coal receiving chute, and the other end is close to one side of the lower end of the vertical elevator; the vertical elevator is close to the belt conveyor, and the upper end lateral part of the vertical elevator is located above the dewatering vibrating screen; the dewatering vibrating screen is located above the belt conveyor, and the water spout is arranged between the dewatering vibrating screen and the belt conveyor; Step S42, the broken coal cut by the cutting gun is mixed with water to form a water-coal flow, which flows out of the coal mining unit and is buffered by the coal receiving chute before falling on the scraper, which directly delivers the transferred water-coal flow to the vertical elevator, which delivers the water-coal flow to the dewatering vibrating screen arranged above the belt conveyor; Step S43, the water-coal flow enters the dewatering vibrating screen and is dehydrated. The dehydrated crushed coal falls directly on the belt conveyor and is sent away. The separated water falls directly on the water dripping plate from the bottom of the dewatering vibrating screen, is guided to one side of the belt conveyor through the water dripping plate, and finally flows into the ditch on the other side of the downstream chute.

10. The green mining method for high-inclination coal seam high-pressure water jet gyratory shredding coal without human face according to claim 8, characterized in that: The process of filling the goaf in step S5 is as follows: Step S51, using steel plates and I-beams to make a grid-shaped guard plate, and using a single pillar to support it, so that the guard plate is close to the outer wall of the coal chute, that is, one side of the lower chute; Step S52, inserting a grouting pipe into the guard plate at the upper edge of the coal chute to monitor whether the coal chute has been filled densely during the grouting process; Step S53, using inorganic grouting material to fill the coal chute, the filling material is poured in from the upper port of the coal mining unit, and the filling material flows down along the inclined bottom plate to the coal chute; Step S54, the filling material of the coal chute reaches 20MPa before the goaf filling can be implemented. At the end of each continuous filling, the steel screen pipe must be quickly flushed and dredged to facilitate the steel screen pipe to extract gas.

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