Alkali-etched roof thick coal seam fully mechanized caving process parameter determination method

Abstract

The invention discloses a method for determining fully-mechanized caving technological parameters of a thick coal seam of an alkali-etched roof, which dynamically adjusts the fully-mechanized caving technological parameters according to the alkali-etched degree, and comprises the following steps of: 1, determining an alkaline water environment and alkaline-etched strength, acquiring and detecting the alkaline water strength of a fully-mechanized caving face, and carrying out generalized partitioning on the alkali-etched degree of the roof; 2, determining a mining and releasing ratio, wherein the mining and releasing ratio determined according to the coal seam thickness and the alkaline corrosion degree must meet the mechanical mining height partition dynamic adjustment principle of coal wall stability and high top coal mining rate; 3, fully mechanized caving process parameters are determined, and the coal caving process and parameters are dynamically determined according to different alkaline corrosion degrees. According to the method, corresponding control parameters are easy, convenient and reasonable to determine, and the problems that the alkali-etched roof is poor in stability, the top coal recovery ratio is low, and fully-mechanized caving technological parameters are difficult to select can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of coal caving in a fully-mechanized caving working face, and in particular to a method for determining process parameters of fully-mechanized caving in a thick coal seam with an alkali-etched roof. Background Art

[0002] Fully mechanized top coal caving is a relatively mature technology for mining thick coal seams, with outstanding characteristics such as high output, low cost and strong adaptability. Scientific and reasonable fully mechanized top coal caving process parameters are of great significance for maintaining the stability of the surrounding rock-support system, improving the top coal recovery rate and improving the production efficiency of the mine. The determination of fully mechanized top coal caving process parameters is highly correlated with geological conditions, coal seam thickness, mechanical equipment, etc.

[0003] The water-rock coupling effect under water-rich roof conditions has become a hot topic in mining engineering research in recent years, and alkaline environmental erosion has intensified the original physical and chemical effects of water and rock. Although some achievements have been made in the research on the technology and theory of fully mechanized caving in thick coal seams, a complete fully mechanized caving theory and technology system has not yet been formed for the conditions of thick coal seams with alkaline-corroded roofs, and there is no ready-made experience to draw on.

[0004] The alkali-corroded roof is highly broken, and the surrounding rock stability of the fully mechanized caving working face is poor. At the same time, the coal-gangue interface is not obvious, and the mixed gangue ratio is high. The top coal caving and migration characteristics under different coal seam thicknesses and alkali corrosion degrees are unclear. Therefore, the determination of fully mechanized caving process parameters in alkali-corroded thick coal seams is an urgent problem to be solved. Summary of the invention

[0005] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a method for determining the process parameters of fully-mechanized caving in thick coal seams with alkali-etched roofs. The method fully considers hydrogeological factors such as coal seam thickness and alkali water strength. The control parameters are determined simply and reasonably, and can effectively avoid practical problems such as poor stability of surrounding rock in alkali water environment and low top coal recovery rate.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for determining the process parameters of fully-mechanized caving in thick coal seams with alkali-corroded roofs, which dynamically determines the process parameters of fully-mechanized caving in thick coal seams according to the alkali-corroded conditions of the roofs of the thick coal seams; the method comprises the following steps:

[0008] Step 1: Determine the alkaline water environment and the degree of alkaline corrosion: According to the alkaline water environment, the degree of alkaline corrosion is generally divided into four levels: weak, medium, strong, and strong;

[0009] Step 2: Determine the mining ratio: dynamically adjust the machine mining height according to the coal seam thickness and alkali corrosion intensity to achieve high recovery rate and surrounding rock stability control;

[0010] Step three, determine the coal caving process parameters for different alkali corrosion zones: dynamically determine reasonable fully mechanized caving process parameters according to the alkali corrosion degree zones.

[0011] Preferably, in step one, the alkaline water environment of the fully-mechanized caving working face is generally zoned according to the roof water spray test results at different positions, and the roof water spray test points are respectively arranged in the air inlet and return air tunnels of the fully-mechanized caving working face, with a spacing of 50m.

[0012] Preferably, in step 1, the pH values ​​corresponding to the weak, medium, relatively strong and strong alkaline corrosion zones are 7-8, 8-10, 10-12 and >12 respectively.

[0013] Preferably, the coal seam thickness for double-wheel coal caving should be above 7.0m, otherwise single-wheel sequential coal caving is adopted.

[0014] Preferably, in step three, the weak alkaline corrosion zone adopts a two-knife-one-release coal mining process, and the coal placing method is a single-wheel single-mouth sequence; the medium alkaline corrosion zone adopts a two-knife-one-release coal mining process, and the coal placing method is a double-wheel single-mouth sequence; when the coal seam thickness in the stronger alkaline corrosion zone is ≤12m, the one-knife-one-release coal mining process is adopted, and when it is greater than 12m, the two-knife-one-release coal mining process is adopted, and the coal placing methods are all double-wheel single-mouth interval; when the coal seam thickness in the strong alkaline corrosion zone is ≤12m, the one-knife-one-release coal mining process is adopted, and when it is greater than 12m, the two-knife-one-release coal mining process is adopted, and the coal placing methods are all double-wheel multi-mouth interval sequence.

[0015] Preferably, in step three, the shearer cutting depth corresponding to the coal mining process is 0.8 or 1.0 m, which is consistent with the coal placement step distance.

[0016] Preferably, in step three, the coal discharge method of the double-wheel multi-opening interval in the roof strong corrosion zone is to divide the hydraulic supports into a group of 3, and when discharging coal, the square coal openings of the odd-numbered and even-numbered hydraulic supports are opened in sequence by first opening the square coal openings of the middle supports in the group, and the maximum speed of the coal cutter, scraper conveyor and scraper chain is required to be at least 3 times the corresponding speed of single-opening coal discharge.

[0017] Preferably, in step three, considering the impact of strong corrosion on roof breakage, the timing of closing the coal discharge port should be a certain period of time after the gangue is seen, rather than stopping coal discharge immediately when the gangue is seen.

[0018] Preferably, the situation where the coal seam thickness is greater than 20m and the mining-to-cavitation ratio is greater than 1:3 is not considered.

[0019] The beneficial effects of the present invention are:

[0020] 1. The mining-to-cavitation ratio control principle and coal caving process parameters adopted in the present invention fully consider the influence of factors such as machine mining height, coal-gangue boundary, and roof alkali corrosion degree on the top coal caving characteristics under different alkaline water environments, and have the characteristics of comprehensive consideration, scientific design, and simple implementation.

[0021] 2. The present invention combines the thickness of the coal seam and the degree of alkali corrosion of the roof to determine a set of highly operational dynamic parameter adjustment methods for fully mechanized top-caving in thick coal seams, which can effectively solve the contradiction between "output-support-surrounding rock" in fully mechanized top-caving in thick coal seams with alkali-corroded roofs.

[0022] 3. The present invention can further reduce the mixed gangue rate, reduce the gangue and coal sorting work, energy consumption and cost, and at the same time, reduce the amount of gangue out of the well and reduce the damage to the environment caused by gangue accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0024] Figure 1 A schematic flow chart of a method for determining process parameters of fully mechanized caving in a thick coal seam with alkali-etched roof provided by an embodiment of the present invention;

[0025] Figure 2 It is a double-wheel group coal placing method;

[0026] Figure 3 A schematic diagram of an alkaline-etched roof environment provided by an embodiment of the present invention; DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] like Figures 1 to 3 As shown, a method for determining process parameters of fully mechanized caving in a thick coal seam with alkali-etched roof comprises the following steps:

[0029] Step 1: Determine the intensity of the alkaline water environment and the degree of alkaline corrosion, obtain and inspect the overall alkaline water intensity distribution characteristics of the target area's air inlet and return air tunnels (measuring point spacing is 50m), and divide them into four levels according to weak alkaline corrosion corresponding to pH=7-8, moderate alkaline corrosion corresponding to pH=8-10, relatively strong alkaline corrosion corresponding to pH=10-12, and strong alkaline corrosion corresponding to pH>12.

[0030] Step 2: Determine the control principle of the mining-to-release ratio and determine the machine mining height based on the coal seam thickness (≤20.0m) and alkali water strength. The general principle is that the machine mining height is directly proportional and inversely proportional to the coal seam thickness and alkali corrosion degree, respectively, but the machine mining height shall not exceed 5.0m.

[0031] Step 3: Determine the coal caving process and parameters for different alkali corrosion levels, and dynamically adjust the fully mechanized caving process parameters in different regions according to the alkali corrosion levels determined in the above steps. When the coal seam thickness is <7.0m, the one-cut-one-caving coal mining process is adopted, and the coal caving method is a single-wheel single-mouth sequence; the weak alkali corrosion zone adopts two-cuts-one-caving, single-wheel single-mouth sequence; the medium alkali corrosion zone adopts two-cuts-one-caving, double-wheel single-mouth sequence; the coal seam thickness in the strong alkali corrosion zone is ≤12m, and the two-cuts-one-caving coal mining process is adopted when it is >12m, and the coal caving method is double-wheel single-mouth interval; the coal seam thickness in the strong alkali corrosion zone is ≤12m, and the two-cuts-one-caving coal mining process is adopted when it is >12m, and the coal caving method is double-wheel multi-mouth interval sequence (one cut corresponds to the coal caving step distance and the coal mining machine cutting depth, and the coal mining machine cutting depth is 0.8m or 1.0m).

[0032] In step three, the double-wheel multi-opening interval coal discharge method is specifically as follows: divide the hydraulic supports into 3 groups, and open all the hydraulic support coal discharge openings in the odd and even groups in turn to perform double-wheel coal discharge. It is required to open the coal discharge opening of the middle hydraulic support in the group first, and the timing of closing the coal discharge opening should be maintained for a certain period of time after the gangue is seen, instead of stopping the coal discharge immediately when the gangue is seen, and the maximum speed of the coal cutter, scraper conveyor, and scraper chain should be at least 3 times the corresponding speed of single-opening coal discharge.

[0033] This embodiment takes a mine in the west as an example, and the specific method includes:

[0034] The first step is to conduct on-site investigation and statistics. The roof alkali water strength is distributed between 7 and 13.7, showing a nonlinear distribution characteristic. In order to more clearly demonstrate the corresponding technology of the present invention, it is simplified and partitioned. Figure 3 The alkaline water strength at 0-200m, 200-400m, 400-800m, and 800-1000m from the opening of the cutting hole is 7.5 (weak alkaline corrosion), 8.5 (medium alkaline corrosion), 11.0 (relatively strong alkaline corrosion), and 13.0 (strong alkaline corrosion); the coal seam thickness is 8.0, 10.0, 11.0, and 19.0m respectively. The on-site coal mining machine cutting depth is 0.8m.

[0035] According to the coal seam thickness and alkaline corrosion degree determined in the first step, the mining ratio, i.e., the machine mining height, is adjusted in different areas. The specific results are shown in Table 1.

[0036] The coal mining technology and coal caving method for different alkali corrosion degrees were determined. The specific results are shown in Table 1.

[0037] Table 1 Alkaline water erosion roof fully mechanized caving process parameters provided in the embodiment

[0038]

[0039] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for determining process parameters of fully mechanized caving in a thick coal seam with alkali-etched roof, characterized in that: According to the alkali corrosion conditions of the thick coal seam roof, the fully mechanized caving process parameters are dynamically determined; the steps include: Step 1: Determine the alkaline water environment and the degree of alkaline corrosion: According to the alkaline water environment, the degree of alkaline corrosion is generally divided into four levels: weak, medium, strong, and strong; Step 2: Determine the mining ratio: dynamically adjust the machine mining height according to the coal seam thickness and alkali corrosion intensity to achieve high recovery rate and surrounding rock stability control; Step three, determine the coal caving process parameters for different alkali corrosion zones: dynamically determine reasonable fully mechanized caving process parameters according to the alkali corrosion degree zones.

2. The method for determining process parameters of fully mechanized caving in an alkali-etched roof thick coal seam according to claim 1, characterized in that: In step one, the alkaline water environment of the fully mechanized caving working face is generally zoned according to the roof water spray test results at different locations. The roof water spray test points are arranged in the air inlet and return air tunnels of the fully mechanized caving working face, with a spacing of 50m.

3. The method for determining process parameters of fully mechanized caving in an alkali-etched roof thick coal seam according to claim 1, characterized in that: In step 1, the pH values ​​corresponding to the weak, medium, strong, and strong alkaline corrosion zones are 7-8, 8-10, 10-12, and >12, respectively.

4. The method for determining process parameters of fully mechanized caving in an alkali-etched roof thick coal seam according to claim 1, characterized in that: The coal seam thickness for which double-wheel coal caving method is adopted is above 7.0m, otherwise single-wheel sequential coal caving method is adopted.

5. The method for determining process parameters of fully mechanized caving in an alkali-etched thick roof coal seam according to claim 1, characterized in that: In step three, the weak alkaline corrosion zone adopts the two-knife-one-release coal mining technology, and the coal releasing method is a single-wheel single-mouth sequence; the medium alkaline corrosion zone adopts the two-knife-one-release coal mining technology, and the coal releasing method is a double-wheel single-mouth sequence; when the thickness of the coal seam in the stronger alkaline corrosion zone is ≤12m, the one-knife-one-release coal mining technology is adopted, and when it is greater than 12m, the two-knife-one-release coal mining technology is adopted, and the coal releasing method is both double-wheel single-mouth interval; when the thickness of the coal seam in the strong alkaline corrosion zone is ≤12m, the one-knife-one-release coal mining technology is adopted, and when it is greater than 12m, the two-knife-one-release coal mining technology is adopted, and the coal releasing method is both double-wheel multiple-mouth interval sequence.

6. A method for determining process parameters of fully mechanized caving in an alkali-etched thick roof coal seam as claimed in claim 5, characterized in that: In step three, the coal mining process corresponds to a shearer cutting depth of 0.8 or 1.0 m, which is consistent with the coal placement step distance.

7. A method for determining process parameters of fully mechanized caving in an alkali-etched thick roof coal seam as claimed in claim 6, characterized in that: In step three, the double-wheel multi-opening interval coal discharge method in the roof strong corrosion zone is to divide the hydraulic supports into a group of 3. When discharging coal, the square coal openings of the odd-numbered and even-numbered hydraulic supports are opened in sequence by first opening the square coal openings of the middle supports in the group. The maximum speed of the coal cutter, scraper conveyor and scraper chain is required to be at least 3 times the corresponding speed of single-opening coal discharge.

8. The method for determining process parameters of fully mechanized caving in an alkali-etched thick roof coal seam according to claim 1, characterized in that: In step three, considering the impact of strong corrosion on roof breakage, the coal outlet should be closed for a certain period of time after the gangue is seen.

9. The method for determining process parameters of fully mechanized caving in an alkali-etched thick roof coal seam according to claim 1, characterized in that: The situation where the coal seam thickness is greater than 20m and the mining-to-gas ratio is greater than 1:3 is not considered.

Images