Method for measuring internal and external air leakage in goaf

Abstract

The application provides a method for measuring internal and external air leakage in a goaf, comprising the following steps: S10, obtaining a calibration roadway and a calibrated roadway; S20, measuring air flow of the calibration roadway and the calibrated roadway during mining; S30, determining surface air leakage according to the air flow of the calibration roadway and the calibrated roadway during mining; S40, measuring total air leakage according to a gas analysis method; and S50, determining internal air leakage according to the total air leakage. The application solves the problem of large measurement error in the prior art.

Description

Technical Field

[0001] This invention relates to the field of coal mining, and more specifically, to a method for measuring the internal and external air leakage of a goaf. Background Technology

[0002] Most shallow-buried coalfields employ underground mining, and the coal seams mined are generally prone to spontaneous combustion, posing a significant threat of spontaneous combustion in the goaf. There are three main factors leading to spontaneous combustion in coal mine goafs: loose coal accumulation, oxygen supply conditions, and heat storage conditions. Since both oxygen supply and heat storage conditions are related to air leakage, air leakage is the primary cause of spontaneous combustion in goafs, making accurate measurement of air leakage particularly important. Air leakage is mainly divided into two categories: external air leakage, i.e., surface air leakage, which generally increases with the shallowness of the coal seam; and internal air leakage within the goaf, caused by the pressure difference between the intake and return air at the working face and the presence of air leakage channels within the goaf. Therefore, the key to fire prevention and extinguishing measures lies in identifying and controlling the main air leakage locations. Thus, changes in air leakage are generally used as an indicator to verify the effectiveness of fire prevention and extinguishing measures.

[0003] Currently, the main methods for determining air leakage inside and outside the goaf include the anemometer method and the tracer gas method. However, these methods have many problems. The anemometer method directly measures leakage with large errors. The anemometer method involves measuring the airflow of the intake and return airflows at the working face separately using an anemometer, and the difference between the two is the leakage amount. The drawback of the anemometer method is that when the leakage amount is small, the measurement error is large, or even no result can be obtained. Because there is a lot of equipment in the underground roadways, it has a significant impact on the ventilation cross-section, making the ventilation cross-section detection results inaccurate. Furthermore, the wind speed at different points in the roadway cross-section is affected by the roadway walls and equipment contours, resulting in inconsistent wind speeds at different points, leading to large errors in the anemometer measurement of airflow, sometimes even exceeding the leakage amount. The tracer gas method for measuring leakage generally involves releasing tracer gas, which is diluted when external leakage is added. The leakage amount can be calculated based on the degree of dilution of the tracer gas. The drawbacks of using tracer gas to detect air leaks are: it can only detect external air leaks, not internal air leaks, and the measurement technology is complex, requires a large number of personnel, and the error is difficult to control. The sulfur hexafluoride tracer gas used has a strong greenhouse effect and is not environmentally friendly, so it cannot be used as a technical means for routine air leak detection.

[0004] In other words, existing methods for measuring air leakage inside and outside goaf areas have the problem of large measurement errors. Summary of the Invention

[0005] The main objective of this invention is to provide a method for measuring the internal and external air leakage of a goaf, so as to solve the problem of large measurement errors in existing methods for measuring internal and external air leakage of a goaf.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for determining the internal and external air leakage of a goaf is provided, comprising: step S10: acquiring a calibration roadway and a roadway to be calibrated; step S20: measuring the air volume of the calibration roadway and the roadway to be calibrated during mining; step S30: determining the surface air leakage based on the air volume of the calibration roadway and the roadway to be calibrated during mining; step S40: measuring the total air leakage using a gas analysis method; and step S50: determining the internal air leakage based on the total air leakage.

[0007] Furthermore, step S10 includes: selecting a roadway with a regular cross-section and no large equipment impact from the intake or return airway of the working face as the calibration roadway; and selecting a roadway other than the calibration roadway as the roadway to be calibrated.

[0008] Furthermore, between step S10 and step S20, the method further includes: measuring the air volume of the pre-mining calibration roadway and the roadway being calibrated to determine the area of ​​the equivalent ventilation cross-section of the roadway being calibrated.

[0009] Furthermore, the process of determining the area of ​​the equivalent ventilation cross-section of the calibrated roadway by measuring the air volume of the calibration roadway and the roadway to be calibrated before mining includes: selecting a cross-section in the calibration roadway as a calibration air measurement station; measuring the area of ​​the roadway cross-section of the calibration air measurement station as the calibration area; measuring the calibration wind speed of the calibration air measurement station; determining the calibration air volume based on the calibration wind speed and the calibration area; selecting a cross-section in the roadway to be calibrated as the calibrated air measurement station; measuring the calibrated wind speed of the calibrated air measurement station; the calibration air volume and the calibrated air volume before mining satisfy formula (1).

[0010] Q1 = Q0 = V0 × S O Formula (1);

[0011] The calibrated air volume satisfies formula (2).

[0012] S1=Q1÷V1 formula (2);

[0013] The area of ​​the equivalent ventilation cross section of the roadway being calibrated is determined according to formulas (1) and (2);

[0014] Where Q1 is the calibrated air volume, in meters (m³). 3 / S; Q0 is the calibration air volume, in meters 3 / S; V0 is the calibration wind speed, in m / s; S0 is the calibration area, in m². 2 S1 represents the area of ​​the equivalent ventilation cross-section, in meters (m²). 2 Q1 represents the calibrated air volume, in meters (m³). 3 / S; V1 is the calibrated wind speed, in m / S.

[0015] Further, step S20 includes: obtaining the calibration mining wind speed from the calibration wind station during mining; determining the calibration mining air volume of the calibration roadway according to formula (3).

[0016] Q′0=V′0×S O Formula (3);

[0017] Obtain the calibrated wind speed at the calibrated wind measurement station during mining;

[0018] The calibrated mining air volume of the calibrated roadway is determined according to formula (4).

[0019] Q′1=V′1×S1 Formula (4);

[0020] Where Q'0 is the calibration extraction air volume, in m³. 3 / S; V'0 is the calibrated mining wind speed, in m / s; S0 is the calibrated area, in m². 2 Q'1 represents the calibrated extraction air volume, in meters. 3 / S; V'1 is the calibrated mining wind speed, in meters. 3 / S; S1 is the area of ​​the equivalent ventilation cross-section, in m². 2 .

[0021] Further, step S30 includes: determining the surface air leakage according to formula (5),

[0022] Q 外 =Q′1-Q′0 formula (5);

[0023] Where Q'0 is the calibration extraction air volume, in m³. 3 / S; Q'1 is the calibrated extraction air volume, in meters. 3 / S;Q 外 Surface air leakage, unit: m³ 3 / S.

[0024] Further, step S40 includes: selecting a gas as the gas for measuring the total air leakage; taking the gas outburst point in the goaf at the return air corner of the working face as the goaf gas sampling point; measuring the calibration mining air volume, the concentration of the gas in the calibration roadway, the calibrated mining air volume, the concentration of the gas in the calibrated roadway, and the concentration of the gas at the sampling point, and obtaining the total air leakage according to formula (6).

[0025] Q 漏 =(Q′1×C′1-Q′0×C′0)÷C′2 Formula (6);

[0026] Among them, Q 漏 Total air leakage, in meters (m). 3 / S;Q'0 is the calibration extraction air volume, in m³. 3 / S; Q'1 is the calibrated extraction air volume, in meters. 3 / S; C'1 is the concentration of the gas measured in the calibrated roadway, in %; C'0 is the concentration of the gas measured in the calibration roadway, in %; C'2 is the concentration of the gas measured at the sampling point, in %.

[0027] Furthermore, in the process of selecting a gas as the measuring gas for measuring the total air leakage, a gas unique to the goaf area or a gas with a low content in the main source of gas is selected as the measuring gas.

[0028] Furthermore, in the process of measuring and calibrating the mining air volume, measuring the gas concentration in the calibration roadway, measuring the gas concentration in the calibrated mining air volume, measuring the gas concentration in the calibrated roadway, measuring the gas concentration at the sampling point, and obtaining the total air leakage according to formula (6), a gas chromatograph is used to analyze the collected gas samples to obtain the gas concentration in the calibration roadway, the gas concentration in the calibrated roadway, and the gas concentration at the sampling point.

[0029] Further, in step S50, the internal air leakage is obtained by subtracting the surface air leakage from the total air leakage, and the calculation formula is as follows:

[0030] Q 内 =Q 漏 -Q 外 Formula (7);

[0031] Among them, Q 内 Internal air leakage, unit: m 3 / S;Q 漏 Total air leakage, in meters (m). 3 / S;Q 外 Surface air leakage, unit: m³ 3 / S.

[0032] The method for determining the internal and external air leakage of a goaf using the technical solution of the present invention includes the following steps: Step S10: Obtaining a calibration roadway and a roadway to be calibrated; Step S20: Measuring the air volume of the calibration roadway and the roadway to be calibrated during mining; Step S30: Determining the surface air leakage based on the air volume of the calibration roadway and the roadway to be calibrated during mining; Step S40: Measuring the total air leakage using a gas analysis method; Step S50: Determining the internal air leakage based on the total air leakage.

[0033] Step S10 involves acquiring the calibration roadway and the roadway to be calibrated before mining begins, avoiding the influence of significant errors in the roadway to be calibrated on the measurement of air leakage. Step S20 measures the air volume of the calibration and roadways during mining. Due to air leakage, the measured air volume differs between the calibration and roadways, allowing for the determination of surface air leakage in step S30. Step S40 measures the total air leakage using gas analysis. A specific gas is selected to analyze its composition, yielding the total air leakage in the goaf. The total air leakage is the sum of surface and internal air leakage; the difference between the total and surface air leakage is the internal air leakage. By clearly identifying internal and external air leakage, the main sources of air leakage in the goaf can be monitored, allowing for targeted sealing of internal or external leakage areas to prevent accidents. This invention solves the problem of large measurement errors in existing methods for determining internal and external air leakage in goafs. Attached Figure Description

[0034] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0035] Figure 1 A schematic diagram of the air leakage process at the working surface according to any embodiment of the present invention is shown;

[0036] Figure 2 It shows Figure 1 A flowchart illustrating the methods for determining the internal and external air leakage in a goaf.

[0037] The above figures include the following reference numerals:

[0038] 1. Calibration roadway; 2. Roadway to be calibrated; 3. Surface air leakage; 4. Internal air leakage; 5. Goaf; 6. Calibration wind measurement station; 7. Wind measurement station to be calibrated; 8. Return air corner of working face; 9. Working face; 10. Fresh air; 11. Stale air; 12. Intake air corner of working face. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0041] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0042] To address the problem of large measurement errors in existing methods for determining air leakage inside and outside goaf areas, this invention provides a method for determining the internal and external air leakage of goaf areas.

[0043] like Figure 1 and Figure 2 As shown, the method for determining the internal air leakage 4 and external air leakage in the goaf includes: Step S10: Obtaining the calibration roadway 1 and the calibrated roadway 2; Step S20: Measuring the air volume of the calibration roadway 1 and the calibrated roadway 2 during mining; Step S30: Determining the surface air leakage 3 based on the air volume of the calibration roadway 1 and the calibrated roadway 2 during mining; Step S40: Measuring the total air leakage using gas analysis; Step S50: Determining the internal air leakage 4 based on the total air leakage.

[0044] In step S10, calibration roadway 1 and the roadway to be calibrated 2 are obtained before the start of mining operations to avoid the large error in the roadway to be calibrated 2 affecting the measurement of air leakage. In step S20, the air volume of calibration roadway 1 and the roadway to be calibrated 2 is measured during mining. At this time, due to the existence of air leakage, the measured air volume of calibration roadway 1 and the roadway to be calibrated 2 are not the same, so the surface air leakage 3 can be determined in step S30. In step S40, the total air leakage is measured by gas analysis. A special gas is selected to analyze the proportion of gas components to obtain the total air leakage of the goaf 5. The total air leakage is the sum of the surface air leakage 3 and the internal air leakage 4. That is, the difference between the total air leakage and the surface air leakage 3 is the internal air leakage 4. By separately identifying the internal air leakage 4 and the external air leakage, the main sources of air leakage in the goaf can be monitored, and targeted sealing of internal or external air leakage areas can be carried out to prevent accidents.

[0045] It should be noted that the surface air leakage of 3 is the external air leakage.

[0046] Example 1

[0047] like Figure 1 As shown, taking a typical U-shaped fully mechanized longwall face as an example, the mine adopts full negative pressure ventilation with the main ventilation fan, and all roadways and ventilation locations underground are under negative pressure. The working face ventilation system consists of three parts: the intake roadway (intake roadway), the working face 9, and the working face return air roadway (return air roadway). Fresh air 10 enters through the working face intake roadway, passes through the working face 9, and finally the waste air 11 is discharged through the return air roadway.

[0048] The air leakage in the goaf 5 of working face 9 is divided into surface air leakage and internal air leakage. The main channel for surface air leakage is that surface air enters the goaf 5 through the collapse and fissures of the goaf 5, and finally enters the working face 9 mainly at the return air corner 8. The main channel for internal air leakage is that a part of the airflow of the working face enters the goaf 5 at the air intake corner 12 of the working face, flows out of the goaf 5 at the return air corner 8 of the working face, and enters the working face 9.

[0049] Step S10 includes: selecting a roadway with a regular cross-section and no large equipment interference from the intake or return airway of the working face as calibration roadway 1; and selecting roadways other than the calibration roadway as the roadway to be calibrated 2. Roadways with regular cross-sections and no large equipment interference have uniform airflow distribution, good wind measurement conditions, and very small wind speed differences at any location, resulting in smaller errors caused by the roadway itself; therefore, they can be used as calibration roadway 1. Other roadways, due to the installation of large equipment such as belt conveyors, have a significant impact on the roadway's wind speed distribution and ventilation cross-section, leading to large errors in airflow measurement; therefore, roadways with these conditions are selected as the roadway to be calibrated 2.

[0050] It should be noted that when there are multiple intake or return air roadways in the working face, the intake or return air roadway containing large equipment in the roadway cross section is taken as the calibration roadway 2. Preferably, there is only one calibration roadway 2, which is the belt conveyor roadway, and the other roadways are calibration roadways 1.

[0051] Specifically, between steps S10 and S20, the process further includes: measuring the air volume of calibration roadway 1 and the roadway to be calibrated 2 before mining to determine the area of ​​the equivalent ventilation cross-section of the roadway to be calibrated 2. Before the initial mining begins, after all equipment in the fully mechanized mining face and the intake and return air roadways is installed, the equivalent ventilation cross-section of the roadway to be calibrated 2 is measured. Before mining, since the goaf 5 has not yet formed, there is no surface air leakage 3, and the air volume of calibration roadway 1 and the roadway to be calibrated 2 is the same. Determining the area of ​​the equivalent ventilation cross-section of the roadway to be calibrated 2 can avoid the influence of the roadway to be calibrated 2's own conditions on the measurement of air leakage, thus ensuring the accuracy of the air leakage measurement results.

[0052] Specifically, the process of determining the area of ​​the equivalent ventilation cross-section of the calibrated roadway 2 by measuring the air volume of calibration roadway 1 and the roadway to be calibrated before mining includes: selecting a cross-section in calibration roadway 1 as calibration air measurement station 6; measuring the area of ​​the roadway cross-section of calibration air measurement station 6 as the calibration area; measuring the calibration air velocity of calibration air measurement station 6; determining the calibration air volume based on the calibration air velocity and calibration area; selecting a cross-section in the roadway to be calibrated as the calibrated air measurement station 7; measuring the calibrated air velocity of the calibrated air measurement station 7; the calibration air volume and the calibrated air volume before mining satisfy formula (1).

[0053] Q1 = Q0 = V0 × S OFormula (1);

[0054] The calibrated air volume satisfies formula (2).

[0055] S1=Q1÷V1 formula (2);

[0056] The area of ​​the equivalent ventilation section of the calibrated roadway 2 is determined according to formulas (1) and (2);

[0057] Where Q1 is the calibrated air volume, in meters (m³). 3 / S; Q0 is the calibration air volume, in meters 3 / S; V0 is the calibration wind speed, in m / s; S0 is the calibration area, in m². 2 S1 represents the area of ​​the equivalent ventilation cross-section, in meters (m²). 2 Q1 represents the calibrated air volume, in meters (m³). 3 / S; V1 is the calibrated wind speed, in m / S.

[0058] A cross-section within the calibration roadway 1 is selected as calibration wind measurement station 6. The area of ​​the roadway cross-section at calibration wind measurement station 6 is measured as the calibration area and calibration wind velocity. The calibration air volume at calibration wind measurement station 6 is obtained according to formula (1). Since there is no surface air leakage before mining, the calibration air volume and the calibrated air volume are equal. Then, the calibrated wind velocity at the calibrated wind measurement station 7 is measured. The area of ​​the equivalent ventilation cross-section of the calibrated roadway 2 is obtained according to formula (2). The equivalent ventilation cross-section can replace the measured cross-section to eliminate the wind measurement error of irregular ventilation roadways.

[0059] It should be noted that the wind speeds of wind measuring station 6 and the calibrated wind measuring station 7 are measured using an anemometer.

[0060] Specifically, step S20 includes: obtaining the calibration mining wind speed of calibration wind station 6 during mining; determining the calibration mining air volume of calibration roadway 1 according to formula (3).

[0061] Q′0=V′0×S O Formula (3);

[0062] Obtain the calibrated mining wind speed at calibrated wind station 7 during mining;

[0063] The calibrated mining air volume of the calibrated roadway 2 is determined according to formula (4).

[0064] Q′1=V′1×S1 Formula (4);

[0065] Where Q'0 is the calibration extraction air volume, in m³. 3 / S; V'0 is the calibrated mining wind speed, in m / s; S0 is the calibrated area, in m². 2 Q'1 represents the calibrated extraction air volume, in meters. 3 / S; V'1 is the calibrated mining wind speed, in meters. 3 / S; S1 is the area of ​​the equivalent ventilation cross-section, in m². 2 .

[0066] After the mining process is completed, the calibration mining velocity at calibration wind station 6 is measured, and the calibration mining air volume of calibration roadway 1 at this time is obtained according to formula (3). The calibration mining velocity at calibration wind station 7 is measured, and the calibration mining air volume of calibration roadway 2 is obtained according to formula (4).

[0067] Specifically, step S30 includes: determining the surface air leakage rate 3 according to formula (5).

[0068] Q 外 =Q′1-Q′0 formula (5);

[0069] Where Q'0 is the calibration extraction air volume, in m³. 3 / S; Q'1 is the calibrated extraction air volume, in meters. 3 / S;Q 外 Surface air leakage, unit: m³ 3 / S.

[0070] Since surface air leakage occurs in the goaf 5 after the mining process, the calibrated mining air volume and the calibrated mining air volume are not the same. According to formula (5), the surface air leakage volume 3 is determined to be the calibrated mining air volume minus the calibrated mining air volume.

[0071] Specifically, step S40 includes: selecting a gas as the gas for measuring the total air leakage; taking the gas outburst point of the goaf 5 at the return air corner 8 of the working face as the gas sampling point of the goaf 5; measuring the calibration mining air volume, the concentration of the gas in the calibration roadway 1, the calibrated mining air volume, the concentration of the gas in the calibrated roadway 2, and the concentration of the gas at the sampling point, and obtaining the total air leakage according to formula (6).

[0072] Q 漏 =(Q′1×C′1-Q′0×C′0)÷C′2 Formula (6);

[0073] Among them, Q 漏 Total air leakage, in meters (m). 3 / S;Q'0 is the calibration extraction air volume, in m³. 3 / S; Q'1 is the calibrated extraction air volume, in meters. 3 / S; C'1 is the concentration of the gas measured in the calibrated roadway, in %; C'0 is the concentration of the gas measured in the calibration roadway, in %; C'2 is the concentration of the gas measured at the sampling point, in %.

[0074] The gas composition in goaf 5 differs from that in the airflow. Leakage in goaf 5 will alter the gas composition in the airflow. The greater the leakage in goaf 5, the greater the change in gas composition in the airflow. Since the return air corner 8 of the longwall mining face is the main channel for leakage in goaf 5, its leakage generally accounts for the majority of the leakage in goaf 5. The gas outburst point of goaf 5 at the return air corner 8 of the working face is used as the gas sampling point for goaf 5, and the gas concentration at the sampling point can be measured. By measuring the calibration mining air volume, the concentration of the gas measured in calibration roadway 1, the calibrated mining air volume, and the concentration of the gas measured in calibration roadway 2, the amount of gas measured in calibration roadway 1 and the amount of gas measured in calibration roadway 2 can be obtained. The difference between the two is the increase in the amount of gas measured in working face 9. Then, according to formula (6), the increase in the amount of measured gas is divided by the concentration of the measured gas at the sampling point, and the resulting value is the total leakage.

[0075] Specifically, in selecting a gas for measuring the total air leakage, a gas unique to goaf 5 or present in low concentrations from its main source is chosen as the measuring gas. Using a gas unique to goaf 5 or present in low concentrations from its main source avoids interference from the components of the measuring gas generated in working face 9, reduces errors in measuring air leakage, ensures the measuring gas has a very low concentration in the airflow, and increases the sensitivity of the measurement process.

[0076] Optionally, carbon monoxide is selected as the gas to be measured. The carbon monoxide content in the intake air is very small, and it is mainly generated during the oxidation of floating coal in the goaf.

[0077] Specifically, in the process of measuring and calibrating the mining air volume, determining the gas concentration in calibration roadway 1, the calibrated mining air volume, the calibrated roadway 2, and the sampling point gas concentration, and obtaining the total air leakage according to formula (6), a gas chromatograph is used to analyze the collected gas samples to obtain the gas concentrations in calibration roadway 1, calibrated roadway 2, and sampling points. Using a gas chromatograph to analyze the collected gas samples can reduce errors and ensure the accuracy of the measurement results.

[0078] Specifically, in step S50, the total air leakage is subtracted from the surface air leakage 3 to obtain the internal air leakage 4. The calculation formula is as follows:

[0079] Q 内 =Q 漏 -Q 外 Formula (7);

[0080] Among them, Q 内 Internal air leakage, unit: m 3 / S;Q 漏 Total air leakage, in meters (m). 3 / S;Q 外 Surface air leakage, unit: m³ 3 / S.

[0081] Subtracting the surface air leakage 3 from the total air leakage using formula (7) yields the internal air leakage 4. This completes the measurement of the internal air leakage 4 and the surface air leakage 3 in the goaf 5.

[0082] To illustrate with an example, consider a mine with shallowly buried, easily spontaneously combustible coal seams. Severe surface air leakage, coupled with internal air leakage in goaf 5, makes spontaneous combustion in goaf 5 a significant concern. Research indicates that fire prevention and extinguishing measures should primarily focus on sealing leaks, with routine measurements of internal and external air leakage to assess the effectiveness of the sealing efforts. However, due to limitations in air leakage measurement methods, the exact air leakage volume in goaf 5 has remained unclear. By employing this method to measure internal and external air leakage, changes in the air leakage volume in goaf 5 can be obtained in real time, playing a crucial role in evaluating the effectiveness of fire prevention and extinguishing measures.

[0083] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0084] 1. Using conventional methods such as anemometers and gas concentration measurements, comprehensive measurements of internal and surface air leakage were achieved at the fully mechanized mining face 9.

[0085] 2. The equivalent ventilation cross-section is measured by comparison method to eliminate the inconsistency of air measurement results caused by the influence of equipment in different roadways, thus ensuring the accuracy of air leakage measurement results;

[0086] 3. Select the unique gas or main source gas of goaf 5 as the measurement object, and calculate the total air leakage based on the total change of the gas in the roadway airflow, so as to ensure the accuracy of the measurement of the total air leakage.

[0087] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0088] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0089] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the internal and external air leakage of a goaf, characterized in that, include: Step S10: Obtain the calibration roadway (1) and the roadway to be calibrated (2); Step S20: Measure the air volume of the calibration roadway (1) and the calibrated roadway (2) during mining; Step S30: Determine the surface air leakage (3) based on the air volume of the calibration tunnel (1) and the calibrated tunnel (2) during mining. Step S40: Measure the total air leakage using gas analysis. Step S50: Determine the internal air leakage based on the total air leakage (4); Step S40 includes: A gas is selected as the gas for measuring the total air leakage. The gas outburst point of the goaf (5) at the return air corner (8) of the working face is taken as the gas sampling point of the goaf (5); The measurement and calibration of the mining air volume, the concentration of gas measured in the calibration roadway (1), the calibrated mining air volume, the concentration of gas measured in the calibrated roadway (2), and the concentration of gas measured at the sampling point are all calculated. The total air leakage is then obtained according to formula (6). Formula (6): Among them, Q 漏 Total air leakage, in meters (m). 3 / S;Q'0 is the calibration extraction air volume, in m³. 3 / S; Q'1 is the calibrated extraction air volume, in meters. 3 / S; C'1 is the concentration of the gas measured in the calibrated tunnel, in %; C'0 is the concentration of the gas measured in the calibration tunnel, in %; C'2 is the concentration of the gas measured at the sampling point, in % In the process of selecting a gas as the gas for measuring the total air leakage, a gas with a low content in the gas unique to the goaf (5) or the main source of the gas is selected as the gas for measuring, so as to reduce the error in measuring the air leakage and ensure that the content of the gas for measuring is very small in the airflow. In step S50, the total air leakage is subtracted from the surface air leakage (3) to obtain the internal air leakage (4), and the calculation formula is as follows: Formula (7): Among them, Q 内 Internal air leakage, unit: m 3 / S;Q 漏 Total air leakage, in meters (m). 3 / S;Q 外 Surface air leakage, unit: m³ 3 / S.

2. The method for measuring the internal and external air leakage of a goaf according to claim 1, characterized in that, Step S10 includes: Select the intake or return air roadway of the working face (9) with a regular cross section and no large equipment influence as the calibration roadway (1). Select roadways other than the calibration roadway (1) as the roadways to be calibrated (2).

3. The method for measuring the internal and external air leakage of a goaf according to claim 1, characterized in that, Between step S10 and step S20, the following is also included: The air volume of the calibration roadway (1) and the calibrated roadway (2) is measured before mining to determine the area of ​​the equivalent ventilation cross section of the calibrated roadway (2).

4. The method for determining the internal and external air leakage of a goaf according to claim 3, characterized in that, The process of measuring the air volume of the calibration roadway (1) and the calibrated roadway (2) before mining to determine the area of ​​the equivalent ventilation cross-section of the calibrated roadway (2) includes: Select a cross section within the calibration tunnel (1) as the calibration wind measurement station (6); The area of ​​the roadway cross section of the calibration wind measurement station (6) is the calibration area; Measure the calibration wind speed of the calibration anemometer station (6); The calibration air volume is determined based on the calibration wind speed and the calibration area. Select a cross section within the calibrated roadway (2) as the calibrated wind measurement station (7); Measure the calibrated wind speed at the calibrated anemometer station (7); The calibration air volume and the calibrated air volume mentioned before mining satisfy formula (1). Formula (1); The calibrated air volume satisfies formula (2). Formula (2); The area of ​​the equivalent ventilation section of the calibrated roadway (2) is determined according to the formula (1) and the formula (2); Where Q1 is the calibrated air volume, in meters (m³). 3 / S; Q0 is the calibration air volume, in meters 3 / S; V0 is the calibration wind speed, in m / s; S0 is the calibration area, in m². 2 S1 represents the area of ​​the equivalent ventilation cross-section, in meters (m²). 2 Q1 represents the calibrated air volume, in meters (m³). 3 / S; V1 is the calibrated wind speed, in m / S.

5. The method for determining the internal and external air leakage of a goaf according to claim 4, characterized in that, Step S20 includes: Obtain the calibrated mining wind speed of the calibration wind station (6) during mining; The calibration ventilation volume of the calibration roadway (1) is determined according to formula (3). Formula (3); Obtain the calibrated mining wind speed of the calibrated wind station (7) during mining; The calibrated mining air volume of the calibrated roadway (2) is determined according to formula (4). Formula (4); Where Q'0 is the calibration extraction air volume, in m³. 3 / S; V'0 is the calibrated mining wind speed, in m / s; S0 is the calibrated area, in m². 2 Q'1 represents the calibrated extraction air volume, in meters. 3 / S; V'1 is the calibrated mining wind speed, in meters. 3 / S; S1 is the area of ​​the equivalent ventilation cross-section, in m². 2 .

6. The method for determining the internal and external air leakage of a goaf according to claim 5, characterized in that, Step S30 includes: The surface air leakage (3) is determined according to formula (5). Formula (5); Where Q'0 is the calibration extraction air volume, in m³. 3 / S; Q'1 is the calibrated extraction air volume, in meters. 3 / S;Q 外 Surface air leakage, unit: m³ 3 / S.

7. The method for determining the internal and external air leakage of a goaf according to claim 1, characterized in that, In the process of measuring and calibrating the mining air volume, measuring the gas concentration in the calibration roadway (1), measuring the gas concentration in the calibrated mining air volume, measuring the gas concentration in the calibrated roadway (2), measuring the gas concentration at the sampling point, and obtaining the total air leakage according to formula (6), a gas chromatograph is used to analyze the collected gas samples to obtain the gas concentration in the calibration roadway (1), the gas concentration in the calibrated roadway (2), and the gas concentration at the sampling point.

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