Shaft and industrial square coal pillar mining method

Abstract

The invention discloses a mineshaft and industrial square coal pillar mining method. The mineshaft and industrial square coal pillar mining method comprises the following steps that S1, a well wall penetrating through a coal seam is replaced with a retractable wood crib; s2, square coal pillars on the periphery of the shaft are subjected to stoping; s3, a mining working face is arranged to be a small working face parallel to the trend or inclination direction of the coal seam, and the industrial square coal pillars are mined in a spiral mining sequence; s4, in the mining process, earth surface monitoring and well wall deformation monitoring are conducted on a shaft; and S5, in the mining process, the stress concentration position or the damage position in the shaft is protected. According to the mining method, the industrial square coal pillars can be effectively recycled, the service life of a mine is prolonged, and coal resources are fully mined, so that the mining rate of the coal resources is increased, and convenience is provided for mining operation of the coal resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal mining, in particular to a method for mining a coal pillar between a shaft and an industrial square. BACKGROUND

[0002] In recent years, with the gradual decrease of coal resources due to increasing exploitation, resources in some mines are close to exhaustion. In order to maximize the exploitation of coal resources and improve the recovery rate of coal resources, it is necessary to further study the recovery of the remaining coal pillar as an effective method to improve the recovery rate of coal resources and extend the service life of the mine.

[0003] The industrial square coal pillar is the largest protective coal pillar left over from the design during the construction period of the general mine. However, when the industrial square coal pillar is mined using conventional mining technology, the mining stress will affect the shaft and the industrial square, thereby causing damage to the shaft and the surface buildings. Therefore, it is necessary to study a method for mining the coal pillar between the shaft and the industrial square to solve the above problems. SUMMARY

[0004] The present application aims to solve the above problems by providing a method for mining a coal pillar between a shaft and an industrial square, which is simple to operate, reduces the impact of mining stress, and protects surface buildings.

[0005] To achieve the above purpose, the technical solution of the present application is as follows:

[0006] A method for mining a coal pillar between a shaft and an industrial square, comprising the following steps:

[0007] S1. Replacing the shaft wall passing through the coal seam with a collapsible wood pile;

[0008] S2. Mining the square coal pillar around the shaft;

[0009] S3. Arranging the mining face parallel to the strike or inclination direction of the coal seam to mine the industrial square coal pillar in a spiral mining sequence;

[0010] S4. During the mining process, monitoring the surface of the shaft and the deformation of the shaft wall;

[0011] S5. During the mining process, protecting the stress concentration position or the damaged position in the shaft.

[0012] Further, in the step S3, the width d of the mining face is determined according to the coal pillar depth, the surface deformation characteristics, and the overburden rock properties.

[0013] Further, in the step S3, the width d of the mining face satisfies the following formula:

[0014] d = (1 / 4 ~ 1 / 10) H0;

[0015] d = L + H1cotψ;

[0016] In the formula, H0 is the coal pillar buried depth; L is the key stratum caving step distance; H1 is the distance between the key stratum and the coal pillar floor; and ψ is the rock mass caving angle.

[0017] The calculation formula of the key stratum caving step distance L is:

[0018]

[0019] In the formula, R is the maximum tensile strength of the key stratum; h is the key stratum thickness; and q is the load on the upper interface of the key stratum.

[0020] The calculation formula of the load q on the upper interface of the key stratum is:

[0021]

[0022] In the formula, E is the elastic modulus of the key stratum, E1…E n is the elastic modulus of each overlying stratum of the key stratum, γ is the unit weight of the key stratum, and γ1…γ n is the unit weight of each overlying stratum of the key stratum.

[0023] Further, in the step S3, the width d of the mining working face is 50-100 m.

[0024] Further, in the step S3, the spiral mining sequence is: first, mining the protective coal pillar with the largest coal pillar buried depth and the length direction being the coal seam strike direction; then, mining the protective coal pillar with the smallest coal pillar buried depth and the length direction being the coal seam strike direction; then, mining the left protective coal pillar farthest from the shaft and the length direction being the coal seam dip direction; and finally, mining the right protective coal pillar farthest from the shaft and the length direction being the coal seam dip direction.

[0025] Further, in the step S4, when the shaft is monitored on the ground surface, the monitoring is performed by a mobile observation station arranged on the ground surface.

[0026] Further, in the step S4, when the shaft wall deformation is monitored, the shaft wall offset is measured by a laser beam method or an inclinometer method; and the shaft wall deformation is measured by a strain gauge or a strain meter.

[0027] Further, in the step S5, the protection of the shaft includes shaft wall protection and arch protection.

[0028] Further, the shaft wall protection is: replacing the rigid shaft wall at the stress concentration position or the damaged position of the shaft wall with a collapsible shaft wall.

[0029] Further, the tank channel protection is that the tank channel beam is cut and connected by sliding clamps, so that the tank channel beam realizes the effect of expansion and contraction.

[0030] Compared with the prior art, the application has the advantages and positive effects that:

[0031] The mining method in the application can effectively avoid the serious damage to the surface building and the shaft caused by the too large coal mining face, and can effectively reduce the stress concentration and shaft deviation caused by the uneven mining of the coal pillar around the shaft by mining the industrial square coal pillar in a spiral manner; meanwhile, the shaft wall deformation and the tank channel deformation can be repaired in time according to the monitoring results of the surface deformation and the shaft deformation, and the mining is stopped in time when the damage degree of the surface and the shaft reaches or exceeds the allowable value, so as to ensure the safety of the important surface building and the shaft; the mining method in the application can effectively recover the industrial square coal pillar, improve the service life of the mine, fully mine the coal resources, and thus improve the coal resource mining rate, thereby providing convenience for the mining operation of the coal resources. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0033] Figure 1 It is a schematic diagram of the rock stratum load mechanical model of the present application;

[0034] Figure 2 It is a schematic diagram of the shaft surface monitoring of the present application;

[0035] Figure 3 It is a schematic diagram of the working face arrangement and mining sequence plane of the present application;

[0036] In the figure, 1, 2, 3…n…m are the overburden of the key rock stratum; A, B, C, D are the shaft and the industrial square coal pillar; O is the geometric center of the protective coal pillar; J1, J2 are the main shaft and the auxiliary shaft; Z1, Z n are the strike observation lines; Q1, Q n are the dip observation lines; A1…An, B1…Bn, C1…Cn, D1…Dn are the distribution points in the working face. DETAILED DESCRIPTION

[0037] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, any modification, equivalent replacement, improvement, etc. obtained by those skilled in the art without creative work should be included in the protection scope of the present application.

[0038] The present application discloses a kind of wellbore and industrial square coal pillar mining method, to protect wellbore and industrial square building (structure), the method is mined in "spiral" way, small working face, to improve coal recovery rate as the purpose.

[0039] The purpose of "spiral" mining is to balance the stress influence caused by working face recovery to wellbore and industrial square as far as possible, while mining coal resources, protect wellbore and surface building (structure);

[0040] Small working face mining, to reduce the size of working face, thereby reducing the mining influence range, realize the purpose of protection to wellbore and surface building (structure), mainly protect wellbore on working face design, reduce surface building (structure);

[0041] The mining method mainly includes the following steps:

[0042] Step 1: before recovery of wellbore and industrial square coal pillar, replace a section of well wall through coal seam with collapsible wood pile;

[0043] Step 2: recovery of square coal pillar near wellbore, the size of square coal pillar is about 40m x 40m;

[0044] Step 3: mining industrial square coal pillar by reasonable working face arrangement and mining sequence;

[0045] Step 3-1: the working face arrangement is: small working face is arranged parallel to the strike or inclination direction of coal seam, and the width of small working face is determined according to the depth of coal pillar, surface deformation characteristics and overburden lithology;

[0046] Step 3-2: the width of small working face is determined according to the depth of coal pillar and surface deformation characteristics, which satisfies the width d = (1 / 4 ~ 1 / 10) H0; usually, the width of working face is 50 ~ 100m;

[0047] Wherein H0 is the depth of coal pillar;

[0048] Step 3-3: the width of working face also needs to be determined according to overburden lithology, that is, the width of small working face also satisfies: d = L + H1cotψ, key strata caving step distance: Load received by the upper interface of key strata: AsFigure 1 As shown;

[0049] Where H1 is the distance between the key rock stratum and the coal pillar floor, ψ is the rock mass collapse angle, R is the maximum tensile strength of the key rock stratum, h is the thickness of the key rock stratum, E is the elastic modulus of the key rock stratum, and E1…E n γ represents the elastic modulus of the overlying rock layers of the key rock layer, γ represents the unit weight of the key rock layer, and γ1…γ n The unit weight of the overlying rock layers is the key rock layer.

[0050] Steps 3-4: As Figure 3 As shown, when mining the coal pillars in the industrial square, the mining sequence is as follows: 1) Mining the protective coal pillar with the greatest burial depth and whose length direction is in the direction of the coal seam strike; 2) Mining the protective coal pillar with the smallest burial depth and whose length direction is in the direction of the coal seam strike; 3) Mining the left protective coal pillar that is farthest from the shaft and whose length direction is in the direction of the coal seam dip; 4) Mining the right protective coal pillar that is farthest from the shaft and whose length direction is in the direction of the coal seam dip; the mining sequence of the small working face is to advance in a "spiral" manner.

[0051] Step 4: During the mining process, surface monitoring and wellbore deformation monitoring are conducted; such as... Figure 2 As shown;

[0052] Step 4-1: Surface monitoring involves deploying mobile surface observation stations to monitor the surface near the wellbore.

[0053] Step 4-2: Wellbore deformation monitoring involves: measuring wellbore offset using the laser beam method or inclinometer method; and measuring wellbore deformation using strain gauges, strain meters, etc.

[0054] Step 5: During the mining process, the wellbore is protected; wellbore protection includes well wall protection and shaft protection;

[0055] Step 5-1: Well wall protection: In areas where stress concentration or damage may occur in the well wall, the original rigid well wall is replaced with a retractable well wall to reduce the damage to the well wall;

[0056] Step 5-2: The tank way protection is that the tank way beam is cut open, and is connected with sliding splints, so that it can be expanded and contracted. The mining method in the application utilizes the advantages of small working face, can effectively avoid the serious damage to the surface building and shaft caused by the too large coal mining working face; and through the "spiral" way to the inside, the industrial square coal pillar is mined, which can effectively reduce the stress concentration and shaft deviation caused by the uneven mining of the coal pillar around the shaft; at the same time, in the mining process, according to the monitoring results of the surface deformation and shaft deformation, the shaft wall deformation and tank way deformation can be repaired in time, when the damage degree of the surface and shaft reaches or exceeds the allowable value, the mining is stopped in time, the safety of the important surface building and shaft is guaranteed; the mining method in the application can effectively recover the industrial square coal pillar, improve the service life of the mine, fully exploit the coal resources, thereby improve the coal resource mining rate, and provide convenience for the coal resource mining operation.

Claims

1. A method of pillar extraction for a shaft and industrial square, characterized by: The method comprises the following steps: S1, replacing the shaft wall through the coal seam with a collapsible timber crib; S2, stoping the square coal pillar outside the shaft; S3, arranging the mining face parallel to the strike or inclination direction of the coal seam into small working faces, and mining the industrial square pillar in a spiral mining sequence; S4, monitoring the surface and shaft wall deformation during the mining process; S5, protecting the stress concentration position or damaged position in the shaft during the mining process.

2. The coal pillar recovery method for a shaft and industrial site according to claim 1, characterized in that: In the step S3, the width d of the mining face is determined according to the coal pillar depth, surface deformation characteristics and overburden lithology.

3. The coal pillar recovery method for a shaft and industrial site according to claim 2, characterized in that: In the step S3, the width d of the mining face satisfies the following formula: d=(1 / 4-1 / 10)H0; d=L+H1cotψ; wherein H0 is the coal pillar depth; L is the key stratum caving step distance; H1 is the distance between the key stratum and the coal pillar floor; and ψ is the rock mass caving angle. The calculation formula of the key stratum caving step distance L is: wherein R is the maximum tensile strength of the key stratum; h is the thickness of the key stratum; and q is the load on the upper interface of the key stratum. The calculation formula of the load q on the upper interface of the key stratum is: In the formula, E is the elastic modulus of the key stratum, E1…E n is the elastic modulus of each overlying stratum of the key stratum, γ is the bulk density of the key stratum, γ1…γ n is the bulk density of each overlying stratum of the key stratum.

4. The coal pillar recovery method of mine shafts and industrial sites of claim 3, wherein: In the step S3, the width d of the mining face is 50-100 m.

5. The coal pillar recovery method for a shaft and industrial site according to claim 1, characterized in that: In the step S3, the spiral mining sequence is: firstly mining the protective coal pillar with the largest depth and the length direction being the strike direction of the coal seam; then mining the protective coal pillar with the smallest depth and the length direction being the strike direction of the coal seam; then mining the left protective coal pillar farthest from the shaft and the length direction being the inclination direction of the coal seam; and finally mining the right protective coal pillar farthest from the shaft and the length direction being the inclination direction of the coal seam.

6. The coal pillar recovery method of mine shafts and industrial sites of claim 1, wherein: In the step S4, the surface monitoring of the shaft is performed by the mobile observation station arranged on the surface.

7. The coal pillar recovery method of mine shafts and industrial sites of claim 1, wherein: In the step S4, the shaft wall deformation monitoring is performed by measuring the shaft wall offset by the laser beam method or the inclinometer method, and measuring the shaft wall deformation by the strain gauge or the strain meter.

8. The coal pillar recovery method of mine shafts and industrial sites of claim 1, wherein: In the step S5, the protection of the shaft includes shaft wall protection and tankway protection.

9. The coal pillar recovery method of mine shafts and industrial plazas of claim 8, wherein: The shaft wall protection is: replacing the rigid shaft wall at the stress concentration position or the damaged position with a collapsible shaft wall.

10. The coal pillar recovery method of mine shafts and industrial plazas of claim 8, wherein: The tankway protection is: cutting the tankway beam and connecting with the sliding clamps to realize the extension effect of the tankway beam.

Images