Triangular coal recovery method for underground coal mining working face of coal mine

Abstract

The invention belongs to the technical field of coal mining, and particularly relates to a triangular coal recovery method for an underground coal mining working face of a coal mine. The mining height is increased at the tail of the coal face, steps are reserved between the tail and a crossheading, and triangular coal loss is reduced by the head of the coal face by adopting a downward conveying and transition slope adjusting method; according to the triangular coal recovery method for the underground coal mine coal face, bottom triangular coal can be effectively recovered by increasing the mining height and the number of the supports at the tail of the coal face, reserving steps between the tail of the coal face and the crossheading and taking corresponding safety technical measures, the coal face is arranged in a downward conveying mode, and compared with an upward conveying mode, the machine head can recover 123 tons of more coal per meter.

Description

Technical Field

[0001] The invention belongs to the technical field of coal seam mining, and in particular relates to a method for recovering triangular coal in an underground coal mining face. Background Art

[0002] When the coal seam thickness is relatively thick (the present invention takes 6.2 meters as an example), in order to strengthen the roof and gas management, prevent the top coal from collapsing and abnormal gas outburst, the coal mining face drift tunnel is excavated along the coal seam roof. The drift height on both sides of the coal mining face is taken as 3.8 meters as an example. The height of the head and tail sections of the coal mining face needs to be gradually transitioned from 3.8 meters to 6.2 meters, resulting in the loss of triangular coal at the head and tail bottom, especially in the area with a larger coal seam inclination.

[0003] It is difficult to control the slope of the transition coal seam floor at the head and tail of the coal mining face. When the transition slope is small, the length of the transition section is large, and the loss of triangular coal increases. When the slope of the transition floor is large, accidents are likely to occur due to improper control. Summary of the Invention

[0004] The invention aims to solve the problem of triangular coal loss at both ends of a coal mining face.

[0005] The present invention provides the following technical solution: a method for recovering triangular coal at an underground coal mining face in a coal mine, wherein the mining height is increased at the tail of the coal mining face machine, a step is left between the tail of the machine and the drift, and the head of the coal mining face machine adopts the method of downward transportation and adjustment of the transition slope to reduce the loss of triangular coal.

[0006] Furthermore, the method for adjusting the transition slope is that at the head of the coal mining face, the coal wall is within the range of 10 hydraulic supports as a flat section, and a transition section is set between the flat section and the coal seam floor.

[0007] Furthermore, the maximum vertical slope angle of the working chute on the coal mining face is 3 degrees, and the vertical curve of the working chute is 35 meters;

[0008] When the coal seam dip angle is between 0 degrees and plus 3 degrees 34 minutes 44 seconds, the flat section is arranged at minus 3 degrees. The method for determining the transition section is to draw a circle c with a radius of 35 meters. The arc section between the tangent point of circle c and the flat section and the tangent point of circle c and the coal seam floor is the transition section.

[0009] When the inclination of the coal seam is greater than positive 3 degrees 34 minutes 44 seconds, the slope of the flat section is greater than negative 3 degrees and less than positive 3 degrees. The method for determining the transition section is to use the length of the flat section as a right-angled side and a radius of 35 meters as the other right-angled side. The length of the hypotenuse is calculated by the Pythagorean theorem. A circle a is drawn with the starting point of the flat section as the center and the length of the hypotenuse as the radius. The coal seam bottom line is offset upward by 35 meters to intersect with circle a. A circle b with a radius of 35 meters is drawn at the intersection point. The arc segment from the end point of the flat section to the tangent point of circle b and the coal seam bottom is the transition section.

[0010] Furthermore, pedestrian stairs and floating bridges are installed at the tail of the coal mining face, and guardrails are installed in front of the tail of the scraper conveyor; and air ducts are installed at the tail sprocket of the scraper conveyor.

[0011] Furthermore, the tail of the coal mining face is supported by additional locking anchor cables, π-shaped steel and side guard plates.

[0012] Compared with the prior art, the advantages of the present invention are:

[0013] The present invention provides a method for recovering triangular coal at an underground coal mining face in a coal mine. The tail of the coal mining face machine can effectively recover bottom triangular coal by increasing the mining height, increasing the number of supports, leaving a step between the tail and the drift, and taking corresponding safety technical measures. The coal mining face adopts a downward transportation layout. Compared with the upward transportation layout, the machine head can recover 123 tons more coal per meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of coal mining face transportation;

[0015] Figure 2 This is a schematic diagram of transportation on the coal mining face;

[0016] Figure 3 This is a schematic diagram of the working slide;

[0017] Figure 4 Schematic diagram of the method for determining the transition section;

[0018] Figure 5 Schematic diagram of the transition section.

[0019] In the figure: 1-chute; 2-head of coal mining working face; 3-tail of coal mining working face; 4-step; 5-coal mining working face; 6-bottom coal dropping range of lower transport; 7-bottom coal dropping range of upper transport; 8-top gangue cutting range of upper transport; 9-; P-flat section; G-transition section. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] like Figure 1 As shown: A method for recovering triangular coal in an underground coal mining face of a coal mine. The mining height at the tail of the coal mining face machine is increased, and a step is left between the tail and the drift. The head of the coal mining face machine adopts the method of downward transportation and adjustment of the transition slope to reduce the loss of triangular coal.

[0022] To ensure safe egress, pedestrian stairs and a floating bridge were installed at the tail of the coal mining face, and a guardrail was installed in front of the tail of the scraper conveyor. An air duct was installed at the tail sprocket of the scraper conveyor to prevent gas accumulation in this area after the tail sprocket is lowered (a special gas inspection point was also established in this area). Locking anchor cables, π-shaped steel, and side guard plates were installed at the tail of the coal mining face to ensure the safety of the roof in the tail triangle area.

[0023] like Figure 2 As shown, when the coal mining face is transported upward, in order to ensure the slope of the flat section and the height of the mining face, the top gangue is cut.

[0024] The comparison results of the bottom coal loss between transporting coal from the coal mining face and transporting coal from the coal mining face under different coal seam inclinations from -9 degrees to 9 degrees are as follows:

[0025] Table 1: Comparison of bottom coal loss between transporting from the coal mining face and transporting from the coal mining face

[0026]

[0027] Comparing Table 1, when the coal seam inclination is between 0 and 9 degrees, the amount of bottom coal lost during downward transportation from the mining face is relatively small, ranging from 61.4 to 28.7 tons. When the coal seam inclination is between 0 and 9 degrees, the amount of bottom coal lost during downward transportation from the mining face is relatively large, ranging from 61.4 to 298.9 tons. Therefore, downward transportation should be used as much as possible in the mining face.

[0028] The method for adjusting the transition slope is that at the head of the coal mining face, due to the equipment layout requirements, the coal wall is within the range of 10 hydraulic supports as a flat section, the maximum slope of the flat section does not exceed ±3 degrees, and a transition section is set between the flat section and the coal seam floor.

[0029] The maximum slope angle of the vertical direction of the working chute on the coal mining working face is 3 degrees. Under the premise of ensuring that the maximum slope angle of the vertical direction of the working chute does not exceed 3 degrees, the vertical curve of the working chute is 35 meters. Figure 3 As shown: when the vertical curve of the working chute is 35 meters, the angle between the two sections of the chute is 2 degrees 53 minutes 41 seconds, which meets the requirement that the maximum slope angle in the vertical direction of the working chute does not exceed 3 degrees.

[0030] like Figure 5As shown: When the coal seam inclination angle of the head section of the coal mining face is equal to positive 3 degrees 34 minutes 44 seconds, after 10 frames are arranged in the flat section at negative 3 degrees, the transition section transitions from a circular arc with a radius of 35 meters at negative 3 degrees to the same angle as the coal seam inclination; when the coal seam inclination angle of the head section of the coal mining face is greater than positive 3 degrees 34 minutes 44 seconds, the slope of the flat section increases accordingly (maximum exceeding positive 3 degrees) to ensure that after 10 frames in the flat section, the circular arc with a radius of 35 meters transitions to the same angle as the coal seam inclination without cutting the bottom gangue. Conclusion: When the coal seam inclination angle of the head section of the coal mining face is less than or equal to positive 3 degrees 34 minutes 44 seconds, the flat section slope is negative 3 degrees; when the coal seam inclination angle of the head section of the coal mining face is greater than positive 3 degrees 34 minutes 44 seconds, the flat section slope is greater than negative 3 degrees and less than positive 3 degrees.

[0031] When the inclination of the coal seam is between 0 degrees and positive 3 degrees 34 minutes 44 seconds, the flat section is arranged at negative 3 degrees. The method for determining the transition section is to draw a circle with a radius of 35 meters. The arc section between the tangent point of the circle and the flat section and the tangent point of the circle and the coal seam bottom plate is the transition section.

[0032] like Figure 4 As shown, when the inclination of the coal seam is greater than positive 3 degrees 34 minutes 44 seconds, the slope of the flat section is greater than negative 3 degrees and less than positive 3 degrees. The method for determining the transition section is to use the length of the flat section as a right-angled side and a radius of 35 meters as the other right-angled side. The length of the hypotenuse is calculated by the Pythagorean theorem. A circle a is drawn with the starting point of the flat section as the center and the length of the hypotenuse as the radius. The coal seam bottom line is offset upward by 35 meters to intersect with circle a. A circle b with a radius of 35 meters is drawn at the intersection point. The arc segment from the end point of the flat section to the tangent point of circle b and the coal seam bottom is the transition section.

[0033] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for recovering triangular coal from a coal mining face in an underground coal mine, characterized in that: The mining height is increased at the tail of the coal mining face machine, and a step is left between the machine and the drift. The head of the coal mining face machine adopts the method of downward transportation and adjustment of the transition slope to reduce the loss of triangular coal.

2. A method for recovering triangular coal from a coal mining face in an underground coal mine according to claim 1, characterized in that: The method for adjusting the transition slope is that at the head of the coal mining face, the coal wall within the range of 10 hydraulic supports is a flat section, and a transition section is set between the flat section and the coal seam floor.

3. A method for recovering triangular coal from a coal mining face in an underground coal mine according to claim 2, characterized in that: The maximum vertical slope angle of the working slide on the coal mining face is 3 degrees, and the vertical curve of the working slide is 35 meters; When the coal seam dip angle is between 0 degrees and positive 3 degrees 34 minutes 44 seconds, the flat section is arranged at negative 3 degrees. The method for determining the transition section is to draw a circle c with a radius of 35 meters. The arc section between the tangent point of circle c and the flat section and the tangent point of circle c and the coal seam floor is the transition section. When the inclination of the coal seam is greater than positive 3 degrees 34 minutes 44 seconds, the slope of the flat section is greater than negative 3 degrees and less than positive 3 degrees. The method for determining the transition section is to use the length of the flat section as a right-angled side and a radius of 35 meters as the other right-angled side. The length of the hypotenuse is calculated by the Pythagorean theorem, and a circle a is drawn with the starting point of the flat section as the center and the length of the hypotenuse as the radius. The coal seam bottom line is offset upward by 35 meters to intersect with circle a, and a circle b with a radius of 35 meters is drawn at the intersection. The arc segment from the end point of the flat section to the tangent point of circle b and the coal seam bottom is the transition section.

4. A method for recovering triangular coal from a coal mining face in an underground coal mine according to claim 1, characterized in that: Pedestrian stairs and floating bridges are installed at the tail of the coal mining face, and guardrails are installed in front of the tail of the scraper conveyor; air ducts are installed at the tail sprocket of the scraper conveyor.

5. A method for recovering triangular coal from a coal mining face in an underground coal mine according to claim 4, characterized in that: The tail of the coal mining face is supported by additional locking anchor cables, π-shaped steel and side guard plates.

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