Method for mining out of space of coal seam in residual mining area of column type with one hole and multiple filling uplink recovery mining

Abstract

The application discloses a method for mining a step-out coal seam of a multi-angle and multi-charge uplink re-mining column type residual mining area. The method comprises the following steps: firstly, judging the feasibility of uplink mining of the step-out coal seam; then, arranging a mining roadway of the step-out coal seam working face, and arranging a filling roadway parallel to the mining roadway in the middle of the working face; injecting filling slurry into the filling roadway to the underlying column type goaf; and after filling the filling slurry into the underlying column type goaf, the step-out coal seam working face is mined. The method can realize multi-angle and omnibearing grouting through one drilling, solves the problem of repeated drilling when grouting the underlying goaf of the uplink re-mining step-out coal seam, effectively improves the mining efficiency of the step-out coal seam working face, and greatly reduces the mining cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mining, and particularly relates to a method for uplink re-mining of a column-type residual mining area. BACKGROUND

[0002] At present, coal resources still play a basic guarantee function in China's energy system, and are the "ballast" of China's energy security and stable supply. With the increasing contradiction between the finiteness of coal resources and the consumption and supply, residual coal re-mining has become an effective way to solve the energy supply and demand contradiction.

[0003] In the long-term process of coal mining, affected by various factors, the situation of uplink re-mining of the overlying coal after the lower coal is mined is formed. In the mining process of the lower coal, the stability and integrity of the roof and floor strata are damaged to different degrees due to the influence of mining operations, and the overburden structure is extremely unstable. If the overlying coal is directly re-mined, it is extremely likely to affect the stability of the overburden roof and floor, thereby causing mine disasters and affecting safety production.

[0004] Therefore, the feasibility evaluation and treatment research of uplink re-mining of overlying coal become the research focus of overlying coal re-mining. In the aspect of uplink re-mining feasibility research of residual mining area, the patent document (publication number CN104239697A) discloses that the influencing factors of uplink mining are modeled by PCA, and then the weight of the established model is calculated by variance contribution rate, so as to evaluate the feasibility of uplink re-mining of residual mining area. The patent document (publication number CN101109283B) discloses a quantitative judgment method of overlying mining feasibility from the perspective of rock structure. According to the specific mining conditions of overlying mining, the feasibility of overlying mining is quantitatively and specifically judged. In the aspect of residual mining area uplink re-mining treatment research, the patent document (publication number CN104790952A) discloses that single-sided filling is carried out on one side of the goaf group, which not only plays a side protection role for the column-type coal pillar group, but also forms a common bearing body to reduce stress concentration. The patent document (publication number CN1108447955B) discloses that the collapsed roof stones and residual coal pillars in the goaf are frozen to form a bearing body, and the lower coal seam goaf is formed as a whole by physical freezing.

[0005] At present, for the column-type uplink re-mining of overlying coal, the main method is to re-mine by grouting and filling in the underlying coal seam goaf. This is because, after the column-type mining method is used for mining, the stability of the coal pillar gradually decreases under long-term pressure, and the coal pillar is prone to instability and collapse. In the process of uplink re-mining of overlying coal, high-intensity longwall mechanized mining and external force are easy to cause large-area coal pillar instability in the column-type goaf, thereby causing large-area collapse of the roof strata of the column-type goaf.

[0006] By the method of filling mining, the underlying knife column type goaf can be grouted to reduce the activation and instability of the underlying knife column type goaf and its coal pillars in the process of repeated mining of the overlying coal seam. However, the current filling method is to arrange drilling holes in the working face to the underlying knife column type goaf, which is affected by the length of the overlying coal seam working face, and a large number of drilling holes need to be arranged to the underlying goaf, which delays the advancing speed of the overlying coal seam working face and increases the production cost.

[0007] In summary, it is urgent to find a method of overlying repeated mining of overlying coal seam with one drilling hole and multi-directional and multi-angle grouting, so as to effectively solve the instability and activation of the coal pillar group in the process of overlying coal seam mining, and to ensure the safety of overlying coal seam mining with low cost and high efficiency. SUMMARY

[0008] In view of the defects in the prior art, the purpose of the present application is to provide a method for overlying repeated mining of overlying coal seam with one hole and multi-charging, which realizes multi-angle and omnidirectional grouting through one drilling hole in the process of overlying coal seam working face mining, provides an efficient and continuous mining working face, and ensures the safety of overlying mining of overlying coal seam.

[0009] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0010] The method for overlying repeated mining of overlying coal seam with one hole and multi-charging comprises the following steps:

[0011] Step 1: Determine the feasibility of overlying mining of overlying coal seam above the column type residual mining area, and find out the distribution characteristics of the coal pillar group in the column type residual mining area;

[0012] Step 2: Excavate the recovery roadway of the overlying coal seam working face, and arrange the overlying coal seam working face and the filling roadway;

[0013] Step 3: Drill a hole in the filling roadway above the underlying goaf knife column type coal pillar, and drill the hole to the vicinity of the intersection surface between the coal pillar and the complete rock stratum roof;

[0014] Step 4: Lower a casing pipe with an inclined elbow in the drill hole, the inclined elbow is in contact with the hole wall at the bottom of the drill hole, a high-pressure hose is lowered in the casing pipe, the bottom of the high-pressure hose is connected with a self-feeding drill bit, the forward borehole jet of the self-feeding drill bit is used for breaking rock drilling, and the reverse borehole jet is used for generating forward thrust, the internal impeller plays a role of pressure boosting, and helps the forward borehole to generate greater pressure for breaking rock;

[0015] Step 5: Make the self-feeding drill bit drill into the goaf along the direction of the casing elbow until it drills into the goaf, stop drilling, remove the self-feeding drill bit, and start grouting and filling. When the filling slurry starts to backflow from the high-pressure hose, stop grouting and filling;

[0016] Step 6: taking out the high-pressure hose, changing the direction of the sleeve, then lowering the high-pressure hose connected with the self-feeding drill bit in the sleeve, repeating step 5, and completing the grouting and filling of the goaf;

[0017] Step 7: after the grouting and filling is completed, the goaf coal seam working face is recovered.

[0018] As preferred, the feasibility of the upward mining of the overlying goaf coal seam in the columnar residual mining area is comprehensively judged by the "three zone" discrimination method, the surrounding rock balance method, the ratio discrimination method, the mathematical analysis method and the quantitative discrimination method described in the Chinese patent with the authorization announcement number CN101109283B in step 1; the width and height of the goaf group and the coal pillar group underlying the columnar residual mining area of the goaf coal seam are found out through the investigation of the original geological technical data of the mine, and the distribution range, size and volume of the goaf group of the columnar residual mining area are accurately detected by using a three-dimensional laser scanner.

[0019] As preferred, the goaf coal seam working face and the recovery roadway are arranged above the underlying residual mining area coal pillar and the goaf in step 3, the filling roadway is arranged at the middle position of the goaf coal seam working face and is parallel to the recovery roadway, and if the goaf coal seam working face is too long or the underlying goaf range is large, a filling roadway can be additionally arranged in the goaf coal seam working face.

[0020] As preferred, the diameter of the drill hole is Φ130mm in step 3.

[0021] As preferred, the hole position deviation of the drill hole is less than 1m and the hole inclination is less than 1° in step 3.

[0022] As preferred, the drill hole in step 3 ends at a position 2-5m away from the intersection surface of the coal pillar and the complete rock roof.

[0023] As preferred, the diameter of the sleeve is Φ90mm and the wall thickness is 8mm in step 4.

[0024] As preferred, the inclination angle of the inclined elbow is -51° in step 4.

[0025] As preferred, the diameter of the high-pressure hose is Φ50mm and the wall thickness is 4mm in step 4.

[0026] As preferred, the filling slurry in step 5 is a mixed slurry of cement and fly ash, and the weight ratio of cement to fly ash is 4:6.

[0027] Compared with the prior art, the beneficial effects of the present application are as follows:

[0028] The present application can realize multi-angle and omnidirectional grouting through one drilling hole in the process of grouting for the overlying coal seam to the underlying pillar-type goaf, can solve the problem of repeated drilling in the process of grouting for the overlying coal seam to the underlying goaf in the up-drawing secondary mining, effectively improves the mining efficiency of the overlying coal seam, and greatly reduces the mining cost. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a filling structure principle schematic diagram of the first coal pillar left side of the pillar-type overlying coal seam working face in the residual mining area.

[0030] Figure 2 It is a filling structure principle schematic diagram of the first coal pillar right side of the pillar-type overlying coal seam working face in the residual mining area.

[0031] Figure 3 It is a filling structure principle schematic diagram of the first coal pillar right side of the pillar-type overlying coal seam working face in the residual mining area.

[0032] Figure 4 It is a filling structure principle schematic diagram of the first coal pillar left side of the pillar-type overlying coal seam working face in the residual mining area.

[0033] Figure 5 It is a filling structure principle schematic diagram of the first coal pillar right side of the pillar-type overlying coal seam working face in the residual mining area.

[0034] Figure 6 It is a filling structure principle schematic diagram of the first coal pillar left side of the pillar-type overlying coal seam working face in the residual mining area.

[0035] Figure 7 It is a filling structure principle schematic diagram of the first coal pillar right side of the pillar-type overlying coal seam working face in the residual mining area.

[0036] Figure 8 It is a filling structure principle schematic diagram of the first coal pillar left side of the pillar-type overlying coal seam working face in the residual mining area.

[0037] Figure 9 It is a filling structure principle schematic diagram of the first coal pillar right side of the pillar-type overlying coal seam working face in the residual mining area.

[0038] Figure 10 It is an internal structure diagram of the high-pressure pump house.

[0039] Figure 11 It is a self-feeding drill bit structure schematic diagram.

[0040] In the figure, 1, the empty coal seam, 2, the interlayer structure, 3, the filling roadway, 4, the borehole, 5, the empty area of the empty coal seam, 6, the working face of the empty coal seam, 7, the coal pillar, 8, the goaf, 9, the casing pipe, 10, the high-pressure hose, 11, the inclined casing pipe elbow, 12, the self-feeding drill bit (12.1, the rear nozzle, 12.2, the front nozzle, 12.3, the impeller), 13, the high-pressure pump station (13.1, the high-pressure pump, 13.2, the flow meter, 13.3, the pressure meter), 14, the water pipe, 15, the filling pipe, 16, the first valve, 17, the second valve. DETAILED DESCRIPTION

[0041] The following examples are intended to illustrate and explain the present application and do not limit the scope of the present application.

[0042] In order to have a clearer understanding of the technical objects, features and effects of the present application, the present application will be further described in detail with reference to the accompanying drawings.

[0043] EMBODIMENT

[0044] In order to ensure the designed production of the mine, a mine violates the conventional mining procedure and arranges the production roadway in the lower No. 9 thick coal seam. The No. 9 coal seam 9301 working face selects the pillar-and-pillar mining method for mining. As the 9301 working face approaches the stop line, the mine has the situation of resource exhaustion and tight mining connection. In order to complete the coal production task, the upper No. 4 thin coal seam is mined again by upward mining, which belongs to the typical pillar-and-pillar residual mining area upward mining of the overlying empty coal seam. The interlayer distance between the No. 9 coal seam and the No. 4 coal seam is 45-50 m.

[0045] In view of the above situation, the present application provides a method for upward mining of the empty coal seam in the pillar-and-pillar residual mining area with one hole and multiple filling, as shown in the figure, and the specific implementation steps are as follows: Figure 1

[0046] Step 1: The feasibility of upward mining of the No. 4 coal seam of the mine is comprehensively judged by using the traditional "three-zone" discrimination method, the confining pressure balance method, the ratio discrimination method, the numerical analysis method and the quantitative discrimination method described in the Chinese patent text with the authorized publication number CN101109283B. It is known from the judgment that the empty coal seam 1 is located in the curved subsidence zone of the interlayer rock 2, and the structural damage degree is small. Therefore, the upward mining of the overlying empty coal seam 1 of the pillar-and-pillar residual mining area is feasible.

[0047] ​Step 2: According to the original geological technical data of the mine, the width of the coal pillar group 7 and the goaf group 8 of the 9301 knife column type residual mining area in No. 9 coal seam is 10-15 m and 15-20 m respectively, and the mining height is 3.5 m; the distribution direction, size and volume of the coal pillar group 7 and the goaf group 8 of the 9301 knife column type residual mining area are accurately surveyed by using a three-dimensional laser scanner, and the distribution pattern diagram of the coal pillar group 7 and the goaf group 8 of the 9301 knife column type residual mining area in No. 9 coal seam is drawn to guide the safe recovery mining of the coal resources in the overlying coal seam 1;

[0048] Step 3: Starting to excavate the recovery roadway of the overlying coal seam 1 on the knife column type residual mining area coal pillar, arranging the overlying coal seam working face 6, excavating the filling roadway 3, and arranging the filling roadway 3 in the middle position of the overlying coal seam working face 6 and parallel to the recovery roadway;

[0049] Step 4: Using the casing drilling technology, drilling the hole 4 above the underlying goaf knife column type coal pillar 7 in the filling roadway 3, casing after drilling the complete bedrock section, and using cement mortar to protect the wall, conducting water pressure test after the hole mouth pipe is consolidated, the maximum pressure is not less than 3 MPa, ensuring no slurry channeling, and the final hole of the hole 4 is at 2-5 m from the intersection surface of the coal pillar and the complete rock roof; the hole diameter of the hole 4 is Φ130 mm, the hole position deviation is less than 1 m, and the hole inclination is less than 1°;

[0050] Step 5: Lowering the casing 9 in the hole 4, the casing 9 is connected with the inclined casing elbow 11 at the bottom, lowering the high-pressure hose 10 in the casing 9, the head of the high-pressure hose 10 is connected with the self-feeding drill bit 12, and the tail is connected with the high-pressure pump station 13; the hole diameter of the casing 9 is Φ90 mm, the pipe wall thickness is 8 mm, the inclination angle of the inclined elbow 11 is-51°, the hole diameter of the high-pressure hose 10 is Φ50 mm, and the pipe wall thickness is 4 mm;

[0051] Step 6: Starting the first valve 16, closing the second valve 17, starting the high-pressure pump station 13.1, and pumping the water in the water pipe 14 to the self-feeding drill bit 12 through the high-pressure pump station 13, the high-pressure water drives the impeller 12.3 to rotate to form a horizontal torrent, the horizontal torrent is sprayed out from the front nozzle 12.2 to break the rock in front of the drill bit, and the rear nozzle 12.1 sprays out to drive the self-feeding drill bit 12 and the high-pressure hose 10 to drill into the goaf; adjusting the water pressure according to the flow meter 13.2 and the pressure gauge 13.3 to stabilize the water pressure at about 3 MPa, so that the self-feeding drill bit 12 continuously advances forward;

[0052] Step 7: When the self-feeding drill bit 12 drills faster, checking whether the self-feeding drill bit 12 drills into the goaf space 8 according to the surveyed goaf shape and drilling distance;

[0053] Step 8: After the self-advancing drill bit 12 drills into the goaf 8, the high-pressure pump 13.1 is closed, the first valve 16 is closed, the self-advancing drill bit 12 is removed, the second valve 17 is opened, the high-pressure pump station 13.1 is started, and the filling slurry is pumped into the goaf along the filling pipe 15 through the high-pressure pump station 13 at a certain angle. The filling slurry is a mixture of cement and fly ash, and the weight ratio of cement to fly ash is 4:6.

[0054] Step 9: When the filling slurry injection is significantly slow and starts to backflow from the high-pressure hose 10, stop the grouting and filling, remove the high-pressure hose, adjust the angle of the casing 9, then lower the high-pressure hose connected with the self-advancing drill bit in the casing, and repeat the operation process of steps 6 to 8 to inject grouting into the goaf 8 on both sides of the first coal pillar of the column-type goaf coal seam working face, as shown in Figure 2 、 3 , 6 and 7;

[0055] Step 10: After the grouting of the goaf on both sides of the first coal pillar of the column-type goaf coal seam working face is completed, repeat steps 4 to 9 to inject grouting into the goaf on both sides of other coal pillars of the column-type goaf coal seam working face, as shown in Figure 4 、 5 , 8 and 9;

[0056] Step 11: After the grouting and filling is completed, the goaf coal seam working face 6 is recovered.

[0057] The above describes the preferred embodiments of the present application, and it should be noted that any improvement and modification of the above-mentioned implementation method without departing from the technical essence and principles of the present application is within the protection scope of the technical solution of the present application.

Claims

1. A method for re-mining coal seams in a pillar-type residual mining area using a single-hole multi-filling method, characterized in that: The method comprises the following steps: Step 1: determining the feasibility of upward mining of the overlying coal seam of the columnar residual mining area, and finding out the distribution characteristics of the columnar group of the columnar residual mining area; Step 2: excavating the mining roadway of the overlying coal seam, arranging the overlying coal seam and the filling roadway; Step 3: drilling a hole in the filling roadway to the exact position above the columnar coal pillar of the underlying goaf, and drilling the hole to the position near the intersection of the columnar coal pillar and the intact rock roof; Step 4: lowering a sleeve with an inclined elbow into the hole, lowering a high-pressure hose in the sleeve, and connecting the bottom of the high-pressure hose with the self-feeding drill bit; Step 5: drilling the self-feeding drill bit along the direction of the sleeve elbow to the goaf, stopping the drilling, removing the self-feeding drill bit, and starting the grouting and filling, and stopping the grouting and filling when the filling slurry starts to backflow from the high-pressure hose; Step 6: removing the high-pressure hose, changing the direction of the sleeve, then lowering the high-pressure hose with the self-feeding drill bit in the sleeve, repeating step 5, and completing the grouting and filling of the goaf; Step 7: after the grouting and filling is completed, the overlying coal seam is mined.

2. The method of claim 1, wherein the method is characterized in that: In step 1, the "three-zone" discrimination method, surrounding rock balance method, ratio discrimination method, mathematical analysis method and quantitative discrimination method are used to comprehensively determine the feasibility of upward mining of the overlying coal seam of the columnar residual mining area; through investigation of the original geological technical data of the mine, the width and height of the columnar group and the coal pillar group of the underlying columnar residual mining area are found out, and the three-dimensional laser scanner is used to accurately detect the distribution range, size and volume of the columnar residual mining area.

3. The method of claim 1, wherein the method further comprises: In step 2, the overlying coal seam and the mining roadway are arranged above the underlying residual mining area and the goaf, and the filling roadway is arranged at the middle position of the overlying coal seam and parallel to the mining roadway.

4. The method of claim 1, wherein the method further comprises: In step 3, the diameter of the hole is Φ130mm.

5. The method of claim 1, wherein the method further comprises: In step 3, the hole position deviation is less than 1m, and the hole inclination is less than 1°.

6. The method of claim 1, wherein the method further comprises: In step 3, the hole is drilled to the position 2-5m away from the intersection of the columnar coal pillar and the intact rock roof.

7. The method of claim 1, wherein the method further comprises: In step 4, the diameter of the sleeve is Φ90mm, and the wall thickness is 8mm.

8. The method of claim 1, wherein the method further comprises: In step 4, the inclination angle of the inclined elbow is -51°.

9. The method of claim 1, wherein the method further comprises: In step 4, the diameter of the high-pressure hose is Φ50mm, and the wall thickness is 4mm.

10. The method of claim 1, wherein the method is characterized by: In step 5, the filling slurry is a mixture of cement and fly ash, and the weight ratio of cement to fly ash is 4:6.

Images