Method for calculating methane emission amount in open coal mine post-mining activity emission boundary range

Abstract

The present application relates to a kind of open coal mine discharge boundary range methane emission amount accurate calculation method, including original ore sample detection, ore sand metering, coal sample selection of coal preparation plant and coal preparation plant methane emission amount calculation etc.Four steps.The present application comprehensively and effectively the parameters related to methane emission after coal resource exploitation are included in the unified calculation system, accurate and comprehensive data calculation of methane emission is realized, so as to achieve the purpose of accurately calculating methane emission during transportation, screening and other processes after coal resource exploitation, and provide accurate reference for greenhouse gas emission statistics and methane resource utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of open coal mine emission boundary range methane emission amount accurate calculation method, belongs to energy survey technology. BACKGROUND

[0002] The mined sand of open coal mine mainly includes lump coal and gravel, then the mined sand is transported to coal preparation plant using truck for further processing. The free state and adsorbed state methane gas in lump coal will continue to diffuse to the outside under the action of pressure gradient and concentration gradient, and the oscillation in the process of truck transportation will aggravate the escape of methane gas in lump coal. Since the methane in the coal body after mining continues to escape, it is of great significance to accurately measure the methane emission amount in the emission boundary range of post-mining activities in open pit mine.

[0003] The existing methane emission measurement method mainly uses empirical parameters to estimate the total methane emission, but the residual methane content in different coal types and geological conditions of open pit coal mine cannot be accurately measured, and it is not suitable for coal bodies produced in high-gas and low-gas mines. At the same time, there are few related researches and patents on methane emission at present. The current "real-time monitoring and measurement method of greenhouse gases in coal mining field and monitoring system" only involves the monitoring of methane emission in coal mine underground, and does not involve the measurement method of methane emission in open pit coal mine. Although the "methane emission factor calculation method for coal washing and selecting enterprises" involves the methane emission factor calculation method for washing and selecting enterprises, it does not involve the measurement of methane emission amount in the emission boundary range, and does not clarify the methane emission range and path. Therefore, the current technical means cannot effectively meet the needs of detection and measurement of methane emission after open pit coal mining.

[0004] Based on the above problems and technical needs, the present application designs a kind of open coal mine emission boundary range methane emission amount accurate calculation method to solve the technical defects and deficiencies in the prior art and meet the needs of actual production. SUMMARY

[0005] The present application aims to provide an open coal mine emission boundary range methane emission amount accurate calculation method. The present application comprehensively and effectively includes the parameters related to methane emission after coal resource mining into a unified calculation system, realizes accurate and comprehensive data calculation of methane emission amount, and achieves the purpose of accurate calculation of methane emission amount during transportation, screening and other processes after coal resource mining, thereby providing accurate reference for greenhouse gas emission statistics and methane resource utilization rate.

[0006] The present application provides an open coal mine emission boundary range methane emission amount accurate calculation method, which mainly includes the following steps.

[0007] A kind of open coal mine discharge boundary range methane emission accurate calculation method, comprising the following steps:

[0008] S1, original ore sample detection, first with 0-20mm, 20mm-50mm, 50mm-100mm, 100mm-300mm, more than 300mm as the standard preparation n type ore sample selection standard, then from the mined sand of open coal mine is randomly sampled, and the sampled sand is concentrated and weighed, and the density of the selected sand is measured by specific gravity measuring instrument, and is recorded as ρ;Then the sampled sand is screened by screening equipment, and is classified and stored after screening and weighing according to the ore sample selection standard, and finally on the one hand, the mass ratio of each type of ore sample in the sand sample is calculated, and the total proportion of each type of coal sample in the sand is taken as the total proportion of each type of coal sample in the sand;On the other hand, the gas content of each type of ore sample is detected by methane content detector, and the particle size and corresponding gas content of n type ore sample are counted, wherein the gas content is recorded as q;

[0009] S2, sand metering, the capacity of the vehicle carrying the mined sand of open coal mine is counted, and is recorded as V, then the number of vehicles transported to the coal preparation plant per day is recorded, and is recorded as X;At the same time, the mass of raw coal screened by the coal preparation plant per day is measured by belt weigher, and is recorded as S;

[0010] S3, coal sample selection of coal preparation plant, first set 0-100mm, 100-300mm, more than 300mm as m type raw coal sample classification standard, then randomly select total coal sample from the raw coal screened in S2 step, and detect the mass and density of total coal sample;Then m type raw coal sample is screened from total coal sample by screening equipment, and finally on the one hand, the proportion of each raw coal sample in total coal sample is calculated, and is recorded as Q';On the other hand, the particle size and corresponding gas content of 3 types of ore sample are counted, wherein the gas content is recorded as q';

[0011] S4, methane emission calculation of coal preparation plant, all the data of S1 step, the data of S2 step and the data of S3 step are put into the calculation function, and the calculation result is calculated by the calculation function, which is the daily methane emission in the discharge boundary range of open coal mine.

[0012] Further, in the S1 step, the mined sand of open coal mine is taken as the sampling point at the initial position of open coal mine mining;When S3 step is carried out, the sampling point is randomly selected from the raw coal pile preliminarily screened by the coal preparation plant;

[0013] Further, in the S4 step, the calculation function is:

[0014]

[0015] In the formula:

[0016] T - the daily methane emissions within the open coal mine post-mining activity emission boundary;

[0017] q - the methane content of the coal sample mined at the open coal mine;

[0018] Q - the percentage of raw coal in the total mass of the coal sample mined at the open coal mine;

[0019] p - the density of the sand;

[0020] V - the capacity of the truck;

[0021] X - the number of trips per day of the truck;

[0022] q' - the residual methane content of the coal sample unloaded at the coal preparation plant;

[0023] Q' - the percentage of raw coal in the total mass of the coal sample unloaded at the coal preparation plant;

[0024] S - the mass of raw coal screened per day at the coal preparation plant.

[0025] Further, in the S2 step, the belt weigher comprises a rack, a belt scale, a feeder, a turnover mechanism and a driving circuit, wherein the rack is a frame structure with a rectangular axial section, the belt scale is embedded in the upper end surface of the rack and is distributed parallel to the rack axis, the feeder is slidingly connected with the upper end surface of the rack and is wrapped outside the upper end surface of the belt scale, the feeder comprises a bearing column, a bearing beam, a flow guide groove, a sliding block and a driving guide rail, wherein the driving guide rail is connected with the upper end surface of the rack, is symmetrically distributed on both sides of the belt scale and is distributed parallel to the belt scale axis, the bearing beam is located above the belt scale, is distributed parallel to the upper end surface of the rack and is distributed perpendicular to the belt scale axis, one end of the bearing beam is connected with one bearing column, the lower end surface of the bearing column is connected with the driving guide rail through the sliding block, and the driving guide rail is slidingly connected with the upper end surface of the rack, the flow guide groove is hinged with the bearing beam through the turnover mechanism, the axis of the flow guide groove intersects with the belt scale axis and forms an angle of 30°-90°, the driving circuit is connected with the outer side surface of the rack and is electrically connected with the belt scale, the turnover mechanism and the driving guide rail of the feeder.

[0026] Furthermore, the guide channel includes a hopper, a guide channel, a drive motor, a pulsator, a scraper, a vibrator, a flow sensor, a flexible connecting pipe, and a control valve. The outer side of the hopper is hinged to the outer side of the supporting beam via a flipping mechanism. The lower end face of the hopper is connected to the upper end face of the guide channel via a flexible connecting pipe. The guide channel has a "U"-shaped cross-section and covers the upper end face of the belt conveyor. The outer side of the guide channel is slidably connected to the frame, and the inner side abuts against and is slidably connected to the outer side of the belt conveyor. The length of the guide channel is at least three times the outer diameter of the lower end face of the hopper. An inlet is provided on the upper end face of the rear half of the guide channel, and the inlet is connected to the hopper via a flexible connecting pipe. The distance between the upper end face of the guide channel and the upper end face of the belt conveyor is not less than 10 cm. At least one pulsator is provided on the lower end face of the top of the guide channel. The axis is perpendicular to and intersects the axis of the guide groove. The impeller is connected to the drive motor through a transmission mechanism. The impeller is located in front of the feed inlet. The drive motor is connected to the upper end face of the guide groove. There are at least three scrapers located inside the guide groove. The rear end face of each scraper is hinged to the inner side of the top and side plates of the guide groove through elastic hinges. The scraper surface forms an angle of 0° to 60° with the top and side plates of the guide groove. Each scraper is located in front of the impeller. The impeller and scrapers are distributed along the axis of the guide groove. The upper end face of the flexible connecting pipe is connected to the hopper through a control valve. A flow sensor is installed inside the flexible connecting pipe. There are at least two vibrators connected to the outer side of the upper end face of the guide groove and distributed along the axis of the guide groove. The drive motor, vibrators, flow sensor, and control valve are all electrically connected to the drive circuit.

[0027] Furthermore, the sidewall of the guide groove is a groove-shaped structure with a cross-section in the shape of an "I". Its outer and inner sides are respectively covered by the groove body outside the frame and the belt. Several guide wheels are evenly distributed along the axis of the guide groove in the bottom of the sidewall of the guide groove. The guide wheels are respectively abutted against and slidably connected to the frame and the belt.

[0028] Furthermore, the supporting column is a structure of at least two-stage electric telescopic rods, and each supporting column is electrically connected to the drive circuit. At the same time, the supporting column is a columnar structure with an axial cross section of "I". The supporting column is connected to the outer side of the guide channel by an auxiliary spring. The auxiliary spring is distributed perpendicularly to the axis of the supporting column, and its two end faces are respectively hinged to the supporting column and the outer side of the guide channel.

[0029] Furthermore, the driving circuit is a circuit system based on a programmable controller.

[0030] Compared with the prior art, the present application comprehensively and effectively brings the parameters related to the methane emission after the coal resource mining into a unified calculation system, realizes the accurate and comprehensive data calculation of the methane emission, so as to achieve the purpose of accurately calculating the methane emission in the transportation and screening processes after the coal resource mining, and the data acquisition and calculation are simple, the data calculation efficiency and precision are high, and accurate reference basis can be provided for the greenhouse gas emission statistics and the methane resource utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a flowchart of the methane emission calculation method of the present application;

[0032] Figure 2 It is a schematic view of the end face of the belt weigher;

[0033] Figure 3 It is a schematic view of the side view of the guide groove;

[0034] Figure 4 It is a schematic view of the top view of the guide groove. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0036] Please refer to Figures 1-4 A method for accurately calculating the methane emission within the emission boundary range of an open-pit coal mine, comprising the following steps:

[0037] S1, original sample detection, first, 0-20mm, 20mm-50mm, 50mm-100mm, 100mm-300mm, more than 300mm are taken as the standard to prepare n types of sample selection standards, then random sampling is performed on the mined sand from the open-pit coal mine, the sampled sand is concentrated and weighed, and the density of the selected sand is measured by a specific gravity measuring instrument, denoted as p; then the sampled sand is sieved by a sieving device, and is classified and stored after being sieved and weighed according to the sample selection standards, finally, on the one hand, the mass ratio of each type of sample in the sand sample is calculated, and is taken as the total proportion of each type of particle size coal sample in the sand; on the other hand, the gas content of each type of sample is detected by a methane content detector, and the particle size of the n types of samples and the corresponding gas content are counted, wherein the gas content is denoted as q;

[0038] S2, the ore sand metering, the capacity of the vehicle carrying the ore sand mined in the open pit coal mine is counted and recorded as V, then the number of vehicle transportation to the coal preparation plant per day is recorded and recorded as X; at the same time, the mass of raw coal screened by the coal preparation plant per day is measured by the belt scale and recorded as S;

[0039] S3, the coal sample selection of the coal preparation plant, first set 0-100mm, 100-300mm, 300mm above as m type raw coal sample classification standard, then randomly select total coal sample from the raw coal screened by the coal preparation plant in S2 step, and detect the mass and density of the total coal sample; then screen m type raw coal sample from the total coal sample through screening equipment, finally on the one hand, the proportion of each raw coal sample in the total coal sample is calculated and recorded as Q'; on the other hand, the particle size of the three types of ore sample and the corresponding gas content are counted, wherein the gas content is recorded as q';

[0040] S4, the calculation of the methane emission amount of the coal preparation plant, the data of S1 step, the data of S2 step and the data of S3 step are all put into the calculation function, and the calculation result is the daily methane emission amount in the emission boundary range of the post-mining activity of the open pit coal mine.

[0041] In this embodiment, in the S1 step, the ore sand mined in the open pit coal mine is taken as the sampling point at the initial position of the open pit coal mine; when the raw coal sample is taken in the S3 step, the sampling point is randomly selected from the raw coal pile preliminarily screened by the coal preparation plant.

[0042] It is emphasized that in the S4 step, the calculation function is:

[0043]

[0044] In the formula:

[0045] T——the daily methane emission amount in the emission boundary range of the post-mining activity of the open pit coal mine;

[0046] q——the methane content of the coal sample mined in the open pit coal mine;

[0047] Q——the percentage of raw coal in the total mass of the coal sample mined in the open pit coal mine;

[0048] ρ——the density of the ore sand;

[0049] V——the capacity of the truck;

[0050] X——the transportation frequency of the truck per day X:

[0051] q'——the residual methane content of the coal sample unloaded by the coal preparation plant;

[0052] Q'——the percentage of raw coal in the total mass of the coal sample unloaded by the coal preparation plant;

[0053] S - the quality of raw coal screened out by the coal preparation plant every day.

[0054] Further optimization, in the S1 step, the sampling quality of each type of ore sample is 500g when the ore sample selection standard is screened; in the S3 step, the coal sample quality is 500g when the coal sample is taken from the raw coal.

[0055] Need special attention, in the S2 step, the belt weigher includes a rack 1, a belt scale 2, a feeder 3, a turnover mechanism 4, and a driving circuit 5, wherein the rack 1 is a frame structure with a rectangular axial section, the belt scale 2 is embedded in the upper end surface of the rack 1 and is distributed parallel to the axis of the rack 1, the feeder 3 is slidingly connected with the upper end surface of the rack 1 and is wrapped outside the upper end surface of the belt scale 2, the feeder 3 includes a bearing column 31, a bearing crossbeam 32, a flow guide groove 33, a sliding block 34, and a driving guide rail 35, wherein the driving guide rail 35 is connected with the upper end surface of the rack 1, is symmetrically distributed on both sides of the belt scale 2, and is distributed parallel to the axis of the belt scale 2, the bearing crossbeam 32 is located above the belt scale 2, is distributed parallel to the upper end surface of the rack 1, and is distributed perpendicular to the axis of the belt scale 2, the bearing crossbeam 32 is vertically connected with one bearing column 31 at each end, the lower end surface of the bearing column 31 is connected with the driving guide rail 35 through the sliding block 34, and the driving guide rail 35 is slidingly connected with the upper end surface of the rack 1, the flow guide groove 33 is hinged with the bearing crossbeam 32 through the turnover mechanism 4, the axis of the flow guide groove 33 intersects with the axis of the belt scale 2 and forms an angle of 30°-90°, and the driving circuit 5 is connected with the outer side surface of the rack 1 and is electrically connected with the belt scale 2, the turnover mechanism 4, and the driving guide rail 35 of the feeder 3.

[0056] In operation, the transported ore sand is conveyed to the belt scale through the feeder, the belt scale is used to weigh and measure the amount of ore sand for screening, and the feeder adjusts the angle between the material flow and the surface of the belt scale during operation through the turnover mechanism, and adjusts the working position of the flow guide groove through the driving guide rail, thereby effectively meeting different use scenarios, such as the need to set the material feeding angle; the material feeding angle can also be adjusted to prevent the accumulation of material on the belt scale and the friction caused by the material to the belt scale, thereby effectively improving the stability and continuity of equipment operation.

[0057] Especially, the guide groove 33 includes a hopper 331, a guide groove 332, a drive motor 333, an impeller 334, a scraper 335, a vibration exciter 336, a flow sensor 337, a flexible connecting pipe 338 and a control valve 339. The outer side of the hopper 331 is hinged to the outer side of the bearing cross beam 32 through a turnover mechanism 4. The lower end surface of the hopper 331 is communicated with the upper end surface of the guide groove 332 through the flexible connecting pipe 338. The guide groove 332 is a "D" shaped groove structure in cross section. The guide groove 332 is covered on the upper end surface of the belt scale 2. The outer side of the guide groove 332 is slidingly connected with the rack 1. The inner side of the guide groove 332 abuts against and is slidingly connected with the outer side of the belt scale 2. The length of the guide groove 332 is at least 3 times of the outer diameter of the lower end of the hopper 331. The upper end surface of the rear half of the guide groove 332 is provided with a feeding port 330. The feeding port 330 is communicated with the hopper 331 through the flexible connecting pipe 338. The distance between the upper end surface of the guide groove 332 and the upper end surface of the belt scale 2 is not less than 10 cm. At least one impeller 334 is arranged on the lower end surface of the top of the guide groove 332. The axis of the impeller 334 is perpendicular to and intersects with the axis of the guide groove 332. The impeller 334 is connected with the drive motor 333 through a transmission mechanism. The impeller 334 is located in front of the feeding port 330. The drive motor 333 is connected with the upper end surface of the guide groove 332. At least three scrapers 335 are arranged in the guide groove 332. The rear end surface of each scraper 335 is hinged to the inner side of the top and side plate of the guide groove 332 through an elastic hinge. The plate surface of the scraper 335 forms an angle of 0°-60° with the top and side plate of the guide groove 332. Each scraper 335 is located in front of the impeller 334. The impeller 334 and the scraper 335 are distributed along the axis direction of the guide groove 332. The upper end surface of the flexible connecting pipe 338 is communicated with the hopper 331 through the control valve 339. Another flow sensor 337 is arranged in the flexible connecting pipe 338. At least two vibration exciters 336 are connected with the outer side of the upper end surface of the guide groove 332 and are distributed along the axis direction of the guide groove 332. The drive motor 333, the vibration exciter 336, the flow sensor 337 and the control valve 339 are electrically connected with the drive circuit.

[0058] When the material is fed through the guide groove, the mineral sand is first conveyed to the hopper. The material in the hopper is conveyed to the belt scale through the flexible connecting pipe to be weighed and conveyed. At the same time, the material is conveyed to the belt scale. The guide groove guides and reforms the material on the belt scale to prevent the material from scattering to cause inaccurate weighing and environmental pollution and resource waste caused by the scattering of the material during conveying.

[0059] Meanwhile, when the ore material is guided and conveyed through the guide groove, on one hand, the material on the belt scale is stirred and uniformly distributed through the wave wheel, so that the uniformity of the material distribution on the belt scale is improved; on the other hand, the material is mechanically vibrated through the vibration exciter, so that the uniformity of the material gap distribution is improved, thereby improving the uniformity of the ore distribution when passing through the belt scale, and the precision of the weighing measurement is improved.

[0060] In the embodiment, the side wall of the guide groove 332 is a groove structure with a cross-section in the shape of a Chinese character 'G', the outer side and the inner side are respectively covered by the groove body outside the rack 1 and the belt scale 2, and the side wall groove bottom of the guide groove 332 is uniformly distributed with a plurality of guide wheels 6 along the guide groove axis, and the guide wheels 6 are respectively abutted and slidably connected with the rack 1 and the belt scale 2.

[0061] The side wall of the guide groove is slidably connected with the rack and the belt scale through the groove structure and the guide wheels, on one hand, the sliding adjustment range between the guide groove and the rack and the belt scale is constrained and limited through the groove structure; on the other hand, the friction loss between the guide groove and the rack and the belt scale is reduced through the guide wheels, and the belt scale is rectified.

[0062] In the embodiment, the bearing column is a two-stage electric telescopic rod structure, and each bearing column is electrically connected with a driving circuit, and the bearing column is a columnar structure with a cross-section in the shape of a Chinese character 'G', and the bearing column is further connected with the outer side of the guide groove through an auxiliary spring, the auxiliary spring is perpendicular to the axis of the bearing column, and the two end surfaces are respectively hinged with the bearing column and the outer side of the guide groove.

[0063] The bearing column adopts a two-stage telescopic structure, and the distance between the feeder and the belt scale can be adjusted according to the use requirement, so that the space between the guide groove of the feeder and the belt scale is adjusted, and the purpose of adjusting the material conveying of the belt scale is achieved.

[0064] In the embodiment, the driving circuit is a circuit system based on a programmable controller.

[0065] Compared with the prior art, the present application comprehensively and effectively includes the parameters related to the methane emission after the coal resource mining into a unified calculation system, realizes the accurate and comprehensive data calculation of the methane emission, so as to achieve the purpose of accurately calculating the methane emission in the transportation and screening processes after the coal resource mining, and provides accurate reference basis for the greenhouse gas emission statistics and the methane resource utilization rate.

[0066] It is to be noted that, in the present text, the relative terms such as first and second, and the like, are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between such entities or operations. Moreover, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, such that processes, methods, articles, or apparatuses that comprise a list of elements are not required to comprise only those elements, but can include other elements not expressly listed or inherent to such processes, methods, articles, or apparatuses. Without further limitation, an element preceded by "comprising" does not, without more limitations, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0067] In the description of the present specification, the terms "connection", "installation", "fixation", "arrangement", and the like are understood in a broad sense, for example, "connection" can be fixed connection or indirectly through intermediate components, or can be integral connection or partial connection, which can be understood according to the specific meaning of the above terms in the present invention or invention according to the specific circumstances.

[0068] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine, characterized in that, The method for calculating methane emissions within the emission boundary of post-mine activities in open-pit coal mines includes the following steps: S1, Original Mineral Sample Testing: First, n types of mineral sample selection criteria are prepared based on standards of 0-20mm, 20mm-50mm, 50mm-100mm, 100mm-300mm, and over 300mm. Then, random samples are taken from the ore sand mined from the open-pit coal mine, and the sampled ore sand is weighed and its density is measured using a specific gravity meter, denoted as ρ. Next, the sampled ore sand is sieved according to the mineral sample selection criteria using a sieve, weighed, and then stored separately. Finally, the mass ratio of each type of mineral sample in the ore sand sample is calculated and used as the total proportion of each particle size in the ore sand. On the other hand, the methane content of each type of mineral sample is detected using a methane content analyzer, and the methane content of each of the n types of mineral samples is statistically analyzed, denoted as q. S2, ore measurement, is used to count the capacity of vehicles transporting ore mined from open-pit coal mines and record it as V. Then, the number of times each vehicle transports ore to the coal preparation plant is recorded each day and recorded as X. At the same time, the mass of raw coal screened by the coal preparation plant each day is measured using a belt weigher and recorded as S. S3, coal sample selection at the coal preparation plant: First, 0-100mm, 100-300mm, and over 300mm are defined as the classification standards for Class m raw coal samples. Then, a total coal sample is randomly selected from the raw coal screened by the coal preparation plant in step S2, and the mass and density of the total coal sample are tested. Next, Class m raw coal samples are screened from the total coal sample using screening equipment. Finally, the proportion of each raw coal sample in the total coal sample is calculated and denoted as Q'. On the other hand, the methane content of the Class m samples is statistically analyzed, and the methane content is denoted as q'. S4, Calculation of methane emissions from the coal preparation plant: Substitute the data from steps S1, S2, and S3 into the final calculation formula. The final calculation formula is as follows: In the formula: T – Daily methane emissions within the emission boundary of post-mine activities in open-pit coal mines; q i —Methane content in coal samples from open-pit mines; Q i —Percentage of raw coal in the total mass of coal samples mined in open-pit coal mines; ρ — density of the ore; V – Truck capacity; X — Number of truck trips per day: q i '——Residual methane content in coal samples unloaded from the coal preparation plant;' Q i '——Percentage of raw coal in the total mass of coal samples unloaded at the coal preparation plant;' S—The quality of raw coal screened out by the coal preparation plant each day; The calculation result represents the daily methane emissions within the emission boundary of open-pit coal mine post-mining activities.

2. The method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine according to claim 1, characterized in that, In step S1, when mining ore from an open-pit coal mine, the initial location of the open-pit coal mine is used as the sampling point; in step S3, when sampling raw coal, sampling points are randomly selected from the raw coal pile initially screened by the coal preparation plant.

3. The method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine according to claim 1, characterized in that, In step S2, the belt weighing device includes a frame, a belt scale, a feeder, a tilting mechanism, and a drive circuit. The frame is a rectangular frame structure with an axial cross-section. The belt scale is embedded in the upper surface of the frame and is distributed parallel to the frame axis. The feeder is slidably connected to the upper surface of the frame and covers the upper surface of the belt scale. The feeder includes a support column, a support beam, a guide groove, a slider, and a drive rail. The drive rail is connected to the upper surface of the frame, symmetrically distributed on both sides of the belt scale, and parallel to the belt scale axis. The load beam is located above the belt scale, parallel to the upper surface of the frame and perpendicular to the belt scale axis. Both ends of the load beam are perpendicularly connected to a load column, and the lower end of the load column is connected to the drive rail via a slider, and is slidably connected to the upper surface of the frame via the drive rail. The guide groove is hinged to the load beam via a flipping mechanism, and its axis intersects the belt scale axis at an angle of 30°–90°. The drive circuit is connected to the outer side of the frame and is electrically connected to the drive rails of the belt scale, the flipping mechanism, and the feeder.

4. The method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine according to claim 3, characterized in that, The guide channel includes a hopper, a guide channel, a drive motor, a pulsator, a scraper, a vibrator, a flow sensor, a flexible connecting pipe, and a control valve. The outer side of the hopper is hinged to the outer side of the supporting beam via a flipping mechanism. The lower end face of the hopper is connected to the upper end face of the guide channel via the flexible connecting pipe. The guide channel has a "U"-shaped cross-section and covers the upper end face of the belt scale. The outer side of the guide channel is slidably connected to the frame, and the inner side abuts against and is slidably connected to the outer side of the belt scale. The length of the guide channel is at least three times the outer diameter of the lower end face of the hopper. An inlet is provided on the upper end face of the rear half of the guide channel, and the inlet is connected to the hopper via the flexible connecting pipe. The distance between the upper end face of the guide channel and the upper end face of the belt scale is not less than 10 cm. At least one pulsator is provided on the lower end face of the top of the guide channel. The axis of the pulsator... The impeller is perpendicular to and intersects the axis of the guide groove, and is connected to the drive motor through a transmission mechanism. The impeller is located in front of the feed inlet, and the drive motor is connected to the upper end face of the guide groove. There are at least three scrapers located inside the guide groove, and the rear end face of each scraper is hinged to the inner side of the top and side plates of the guide groove through elastic hinges. The scraper surface forms an angle of 0° to 60° with the top and side plates of the guide groove, and each scraper is located in front of the impeller. The impeller and scrapers are distributed along the axis of the guide groove. The upper end face of the flexible connecting pipe is connected to the hopper through a control valve, and a flow sensor is installed inside the flexible connecting pipe. There are at least two vibrators connected to the outer side of the upper end face of the guide groove and distributed along the axis of the guide groove. The drive motor, vibrators, flow sensor and control valve are all electrically connected to the drive circuit.

5. The method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine according to claim 4, characterized in that, The sidewall of the guide groove is a groove structure with an "I" shaped cross section. Its outer and inner sides are covered by the groove body to cover the frame and belt respectively. Several guide wheels are evenly distributed along the axis of the guide groove in the bottom of the sidewall of the guide groove. The guide wheels are abutted and slidably connected to the frame and belt scale respectively.

6. The method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine according to claim 3, characterized in that, The supporting column is a structure of at least two-stage electric telescopic rods, and each supporting column is electrically connected to the drive circuit. At the same time, the supporting column is a columnar structure with an axial cross section of "I". The supporting column is connected to the outer side of the guide channel by an auxiliary spring. The auxiliary spring is distributed perpendicularly to the axis of the supporting column, and its two end faces are respectively hinged to the supporting column and the outer side of the guide channel.

7. The method for accurately calculating methane emissions within the emission boundary of an open-pit coal mine according to claim 3, characterized in that, The drive circuit is a circuit system based on a programmable controller.

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