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THE MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF MINING AND GEOLOGY - NGUYEN VAN THINH RESEARCH ON METHANE DRAINAGE REGIME WHEN EXPLOITING TO DEEP IN UNDERGROUND COAL MINES IN QUANG NINH AREA Specializ: Mining Code: 9520603 SUMMARY OF TECHNICAL DOCTORAL THESIS HANOI - 2019 Thesis is finished at Department of Underground mining, Faculty Mines, Ha Noi University of Mining and Geology Scientific advisors: Assoc.Prof.Dr Dang Vu Chi, Hanoi University of mining and geology Dr Le Van Thao, Vietnam Mining Science and Technology Association Reporter 1: Prof.Dr.Sc Le Nhu Hung, Vietnam Mining Science and Technology Association; Reporter 2: Dr Nguyen Anh Tuan, Vietnam National coal and mineral industries holding Corporation limited; Reporter 3: Dr Dao Hong Quang, Vinacomin Institute of Mining Science anh Technology The thesis will be defended before the school level of thesis jury in Ha Noi University of Mining and Geology at……………………2019 The thesis can be found at: - National Library; - Library of the University of Mining and Geology MỞ ĐẦU Necessity of thesis According to the Decision No 403 / QD-TTg dated March 14, 2016 of the Prime Minister on approving the adjustment of the development planning of Vietnam's coal industry to 2020, considering the prospects until 2030, at Article 1, Section II.2.b states "The volume of commercial coal produced in the industry in the planning stages: About 41 - 44 million tons in 2016; 47-50 million tons by 2020; 51 - 54 million tons in 2025 and 55-57 million tons in 2030 " In order to meet the requirements for the output of pit coal mines, it is increasingly necessary to go deep, expand the scale as well as apply mechanization in mining and digging The increase in coal production leads to the amount of methane being released to the ovens and the furnace to prepare more and more Methane is a gas that can cause very dangerous explosions In the history of pit coal mining in the world and in Vietnam, there have been many CH4 gas explosions that have killed dozens, even hundreds, of people and destroyed the facilities of coal mines Due to the dangerous nature of methane released in the pit of mines causing the risk of fire and explosion, the coal mining industry in the world as well as in Vietnam always put the issue of methane fire prevention and fighting on top, including the study of methane drainage and methane storage in coal seams is the source of the release of methane gas into mine kilns In our country, the researches on gas storage and methane drainage have been carried out for many years but mainly focused on mines with high gas emission, not yet universal and have not been proposed newspaper when exploiting deep into each mineral deposit or underground coal mine to take measures to prevent gas accumulation exceeding the effective permissible limit In order to assess the danger of methane for each coal mine or mining area, it is necessary to determine the methane release mode of the mine or mining area Of particular importance is the study of determining the containment of methane in coal seams and the degree of leaching of gases to quantify mine kilns in a quantitative way to apply the method of exploiting and using room facilities Suitable methane explosion protection and safety guarantee and improve economic efficiency Therefore, "Research on methane drainage regime when exploiting to deep in underground coal mine in Quang Ninh region" is urgent Research aim of thesis - Study on methane drainage regime in underground coal mines in Quang Ninh area when exploiting deeply - Proposing suitable solutions for preventing and combating methane fire when exploiting in underground coal mines in Quang Ninh region 4 Research objective and scope Object of the study: Gas emission and methane content in coal seams affect the mining process down to underground coal mines in Quang Ninh Scope of research: The topic is underground coal mines in Quang Ninh Research content - An overview of the study on the regime of methane drainage in pit coal mines in the world and in Vietnam - Study the characteristics of methane gas storage when exploiting deep in coal seams of coal mines in Quang Ninh region - Study the methane gas escape when exploiting deep in underground coal mines in Quang Ninh region - Study and propose suitable solutions to prevent methane fire and explosion for underground coal mines in Quang Ninh Research Methods The thesis uses a combination of the following research methods: - Methods of surveying, synthesizing and inheriting documents; - Methods of analysis, statistics and graph methods; - Methods of linear interpolation and non-linearity Scientific and practical meaning of thesis 6.1 Scientific meaning: - Develop regression functions using the least squares method to forecast gas storage and methane release in underground coal mines in Quang Ninh region; - Predict the process of methane release into mining areas on the basis of determining the level of methane drainage at the extraction level on her forecasting methane drainage for the next extraction level 6.2 Practical meaning: The research results contribute to the determination and prediction of methane drainage and coal mining areas of coal mines in Quang Ninh in the deep exploitation areas to take appropriate measures to prevent methane explosion New points of thesis - Constructing regression function on the methane gas storage in coal seams in underground coal mines in Quang Ninh region with the form y = a.xb - Establish a map of methane zoning according to the scope and depth of underground coal mines in Quang Ninh region - Forecast of methane release for market ovens at underground coal mines in Quang Ninh area, with actual measurement results by multiplying forecast results with coefficient k = 0,9316 and plus 0.0029 Scientific thesis - The deeper the mining, the higher the gas storage and methane release; - Same geological condition, methane drainage depends on coal seam thickness and mining output; - For the system of mining and division of layers, the methane drainage in the upper layer is greater than the escape of methane in the lower layer The thesis structure The thesis consists of chapters, Introduction sections and Conclusion conclusions, pages, including drawings and tables Chapter OVERVIEW OF METHODS TO STUDY METHANE DRAINAGE IN UNDERGROUND COAL MINES IN THE WORLD AND VIETNAM 1.1 GENERAL CHARACTERISTICS OF METHANE Methane (CH4) is the simplest type of saturated carbonate of paraffin group Colorless gas, odorless, tasteless Its density in normal conditions is 0.716 kg / m3, which is several times lighter than air It is soluble in ethanol, ether, poorly dissolved in water (up to 3.5% under normal conditions) Although methane is a gas that does not affect respiration, significant concentrations in the air are dangerous because methane gas pushes oxygen (4.8% methane will push 1% oxygen) Methane is a potentially explosive gas When the volume content of methane is in the range of - 15% and the minimum oxygen content of about 8% of the mixture is explosive, the explosive mixture is strongest when the methane content reaches 9.5% The explosion limit of methane is not fixed and depends on the pressure, temperature, combustion position and initial heating intensity Under reduced pressure, the explosion limit will shrink In the direction of increasing temperature - the explosion limit will expand and vice versa 1.2 OVERVIEW OF METHODS TO STUDY METHANE DRAINAGE IN UNDERGROUND COAL MINES IN THE WORLD a Methods in Western European countries In Western European countries, people often use the method of forecasting the methane escape into the oven by Shulza, Wintera and Stuffkena Inside: M- Released gas relative to the longwall (m3CH4/T-ng.đ) Wtn- Do contains natural gas of coal seams (m3CH4/T) Wlc- Gas reservoir of nearby reservoir (m3CH4/T) mlc- Thickness of adjacent seams; (m) mkt- Thickness of exploitation seam nlc - Number of air discharges from adjacent reservoirs (above or below), this number depends on the distance from the adjacent seams to the existing seams b Statistical method of the Soviet Union The basis of this method is the system of statistic data in the past in terms of air discharge of the mining area or exploitation floor and other factors such as extraction level and length of longwall The accuracy of the method depends on the reliability of the statistics The methane emission of the new extraction level is calculated according to the formula: Inside: Mp - The level of methane emission of the extraction level m3/Tngđ H – Depth of new cascade level (m) (m) H0- Depth of methane-containing cliff wall (m) L- The gas-rich level indicates the depth increase so that the relative air discharge increases by m3CH4 / T-ng.đ; unit (m/m3CH4/T) The value of the gas-rich level L is summarized from the statistics collected at the already and exploited levels The L value is determined by the following formula: H1- Exploitation depth of shallow level (m) H2- Depth of exploitation of deeper level (m) Mp1- The methane drainage is shallow (m3CH4/T-ng.đ) Mp2- The methane drainage is deep (m3CH4/T-ng.đ) For mines with many statistics of H1, H2 and different Mp1 Mp2 values, the relationship between M- relative discharge and H- depth of exploitation can be shown On the basis of the regular line M = f (H), we can predict the predicted Mp gas discharge according to the depth value of the new exploitation level In this method, the higher the number of Mpi and Hi statistics, the higher the forecast The drawback of the method is that there is a need for many statistical figures over the years at different levels c Method of forecasting the methane release from the extraction area of experimental mine "Barbara", Poland According to this method, the absolute solubility of methane released into the oven is calculated according to the following general formula: Vkt: Escape methane gas from coal mining, m3/ph - Llc : Length of longwall, m - mkh : The thickness of the exploitation layer, m - Yv : Volumetric weight of coal in the seams T/m - Wv : The content of methane in the coal seams m3/ Tkhối cháy - Vg: Methane gas escapes from the face of longwall - Vtr: Methane gas escapes from above of the longwall - Vdi: Methane gas escapes from the bottom of the longwall - p - Mining speed of longwall, m/ngđ 1.3 OVERVIEW OF METHODS TO STUDY METHANE DRAINAGE UNDERGROUND COAL MINES IN VIETNAM Research on methane drainage in Vietnam has been mentioned by a number of authors such as Tran Tu Ba and Le Van Thao Currently, in Vietnam is using the method of rigorous mine "Barbara" of Poland to study the application of prediction of air discharge into a longwall suitable for the conditions of Vietnamese underground coal mines because: Geological and technological factors of Polish and Vietnamese underground mines are not similar Especially if talking about geologicalmining conditions, Poland's coal is energy coal (Bitumineous), while Vietnam coal is coal-anthracite (Anthracite) The coal seams of Poland are quite deep (thousands of meters) and most of them are curb The coal seams in Quang Ninh area are mostly steep ones, which are closer to the ground (currently, the deepest coal mine in Vietnam is Khe Cham II-IV coal mine is expected to reach -500 and will produce output in 2022) For that reason, it is necessary to calculate and control the actual measurement results to be able to propose adjustment coefficients to suit the geological conditions of underground mines in Quang Ninh area 1.4 REVIEW CHAPTER - Methane is a dangerous gas for coal mines exploited by pit method because this gas appears regularly in coal mines (especially mines of anthracite and anthracite coal as in Quang Ninh area) ) and when a methane explosion occurs, it often causes great loss of life and property and affects the mine production - The demand for coal in the world as well as in Vietnam is increasing At the same time, the coal output exploited by pit method is increasing in proportion to the exploitation by opencast method Therefore, the issue of ensuring the safety of methane fire in underground coal mines needs to be put on top - There are two main methods to study the storage and escape of methane methane: Study on the storage and drainage of methane in the geological exploration and study of the storage and drainage of methane in the extraction process In Vietnam Study the storage and drainage of methane during geological exploration with little data, used to serve the initial mine design work; Study on the storage and drainage of methane in the mining process used to classify mines 8 Chapter CHARACTERISTICS OF METHANE CONTENT OF COAL SEAMS IN UNDERGROUND COAL MINES IN QUANG NINH 2.1 GENERAL CHARACTERRISTICS OF METHANE STORAGE IN COAL SEAMS The concentration of methane is the amount of methane gas calculated according to the standard conditions in ton of combustion coal block The determinant of the level of methane containing coal deposits is the closest tectonic change Coal seams with conditions of methane accumulation are usually the reservoirs below the gas-permeable layer of soil The phenomenon of gas-permeable coal seam layers does not create two types of closed and open mineral forms The level of each reservoir of methane gas in the minerals depends on the existence of methane separation layers The characteristic of closed type deposits is the coexistence of gaspermeable coal seam layers both in the covering soil layers and in carbon lava layers alternating between coal seams Thus the layers of this separation, the shift of methane from the deeper layers slowed down As the depth of extraction increases, this type of mineral methane content increases and there is a difference in each coal seams 2.2 GEOLOGICAL CHARATERISTICS OF QUANG NINH COAL AREA Coal mines in Quang Ninh coal basin are affected by very strong bending and fracturing activities, highly degraded coal In Quang Ninh coal basin, there are over 84.5% of coal mines belong to group III, only a few belong to group II and mine group IV However, the grouping of mines is essentially an average value Each coal mine has its own geometric fields in each high homogeneous architectural block and has geometric anisotropic characteristics with different anisotropic coefficients Within the coal basin, the sediments of the Hon Gai Formation have the largest distribution area, concentrating into two large bands near the longitudinal parallel between the area of Bao Dai and Pha Lai - Ke Bao Quang Ninh coal basin sediments are uniformly classified by geologists as age (T3n - r) and named Hon Gai formation The physical composition is almost identical and the monotone repetition of the same rock layers in the section, it is difficult to divide the stratigraphic and the cross-sectional comparison only has relative meaning 2.3 RESULTS OF DETERMINATION OF METHANE STORAGE IN COAL SEAMS IN UNDERGROUND COAL MINES IN QUANG NINH Table Results of analysis of methane concentration in coal seams of underground mines in Quang Ninh region Name of coal mines Name of coal seams Level The average value of methane in coal seams, m3/TKC Note 1Cb MaoKhe coal mine 9b 10 50 -25 -70 -120 -150 -15 -59 -80 -100 -150 30 -25 -60 -80 -100 -150 -25 -50 -80 -120 -150 -25 -50 -80 -135 -150 30 -25 -57 -80 -120 -25 -58 -68 -80 -105 70 32 -25 -38 0.01787 0.311 0.32033 0.462 0.634 0.253 0.467 0.78 0.825 1.05 0.299 0.399 0.422 0.456 0.672 0.9582 0.366 0.938 1.01266 1.342 1.5785 0.367 0.52639 1.418 1.83364 1.988 0.356 0.698 1.389 2.26722 3.59497 0.1479 0.4141 0.8571 1.423 1.635 0.21066 0.289 0.375 0.661 10 10 HaLam coal mine 11 14 12 KheCham coal mine 13.1a -80 -95 +10 +5 -10 -40 -46 -50 -65 -90 -150 0.936 1.029 0.061 0.0704 0.1131 0.1726 0.196817 0.24 0.2515 0.26385 0.2988 0.332 -200 0.37578 -46 -50 -70 -100 -110 -130 -145 -160 -250 +12 -25 -80 -90 -110 -150 -300 -120 -130 -140 -160 -180 -200 -110 -125 -130 -120 -163 0.01034 0.072 0.15 0.2311 0.25193 0.2745 0.262 0.2961 0.37494 0.105 0.192 0.208 0.217 0.239 0.272 0.35953 1.5 2.203 2.809 3.282 3.37104 3.916 2.263 3.53632 3.81109 3.976 4.8583 11 13.1 13.2 14.2 14.4 14.5 -200 -90 -100 -120 -130 -180 -225 -56 -100 -105 -120 -147 -152 -164 -190 -37 -45 -75 -80 -91 -94 -110 -124 -140 +69 -28 -45 -90 -100 -124 -150 -168 +59 +35 +3 -50 -71 -100 -140 5.302 3.37501 3.50684 4.758 4.827 5.02296 6.29 1.103 1.82 2.212 2.6 3.161 3.607 3.86856 4.148 1.522 2.19 2.386 2.661 3.114 3.14 3.66089 3.96833 4.2122 0.3064 0.38 0.8 1.055456 1.28536 1.21072 1.331 1.419 0.13684 1.0207 1.1666 1.19645 2.089 2.089 2.49023 12 2.4 STUDY THE RULES OF METHANE DISTRIBUTION UNDERGROUND COAL MINES IN QUANG NINH IN The change of the reservoir depth of methane in the reservoir of Mao Khe, Ha Lam and Khe Cham mines is determined from the input data by the empirical regression method based on the relationship y = a.x b and shown on the following picture: Figure Variation of methane gas content in coal seams of Mao Khe Figure Variation of methane gas content in coal seams of Ha Lam 13 Figure Variation of methane gas content in coal seams of Khe Cham From the graphs of the variation of methane gas in the depth of coal seams, the methane gas content increases with the depth of the reservoir and the methane gas content is in compliance with the regression function in the form of y = a.xb with variables x is the depth (elevation) of coal seams, y is the level of methane gas at depth x Depending on specific conditions of each reservoir, there are different values of a and b 2.5 REVIEW CHAPTER From the results of research on methane gas storage for coal seams of mines The thesis has some following remarks: - The content of methane gas increases with the depth of the reservoir as well as the mine according to the rule y = a.xb - In Quang Ninh coal basin, underground mines also divide into areas with high methane content and lower methane gas storage area Areas with high levels of methane are shown in the mines: Mao Khe, Dong Vong, Quang Hanh, Duong Huy, Khe Cham (class III and super class mines) The remaining coal mines of Quang Ninh area have the methane content in low coal seams (mainly mines of class I and II) 14 Chapter STUDY ON THE REGIME OF METHANE DRAINAGE WHEN EXPLOITING DEEPLY IN UNDERGROUND COAL MINES IN QUANG NINH 3.1 STUDY ON METHANE DRAINAGE IN UNDERGROUND COAL MINE IN QUANG NINH To study the influence of geological factors affecting the escape of methane in the furnace, it is necessary to select coal seams with different gas concentrations, thus clearly reflecting the influence of gas storage methane dissolves in coal seams to escape methane gas into the oven of the mining market The author chooses typical market ovens in the areas of Quang Ninh coal region as follows Figure Relationship between yield and absolute methane escape in MaoKhe coal mine 15 Figure Relationship between yield and absolute methane escape in HaLam coal mine Figure Relationship between yield and absolute methane escape in Khe Cham 1coal mine 16 Figure Volume of methane gas released from underground coal mines 3.2 FORECAST OF METHANE DRAINAGE IN UNDERGROUND COAL MINES IN QUANG NINH WHEN EXPLOITING DEEPLY Based on the above analysis, the author selects Poland's method as the basic method for research to apply in calculating the forecast of air discharge into the furnace to suit the conditions of underground coal mines oven in Vietnam Figure Each correlation between forecast results and actual measurement results of methane escape 17 The results of the forecast calculation and the actual results of the actual drainage of the long-term exhaust gas from the long-term market of companies with high gas storage in each area of Mao Khe, Uong Bi, Hon Gai and Cam Pha are presented in the above table shows: - The results of the forecast and the actual measurement results are not much different, with the regression function by the method of minimum square has the form: y=0,8651x +0,00246 with a deviation of R2=0,9896 Therefore, the forecasted results to apply in practice need to be multiplied by the coefficient k = 0,8651x and plus 0,00246 - The results of the forecast of absolute air discharge of the areas are generally higher than the actual measurement results 3.3 REVIEW CHAPTER The level of methane escape in the longwall, in the various technological fluxes are subject to the general rule and the main dependence on methane gas storage and the quantity of longwall mining is: Relative methane emissions and methane emissions absolutely increase as methane gas increases As mining output rises, the methane escaping is absolutely increasing, but the relative emissions of methane are reduced From the above average combined results table shows that the methane volume of the mines all tend to increase next year On the other hand, mines are exploited further and the output of exploitation does not increase much, so it is said that when exploiting deeply, the amount of methane released from the mining areas will increase Chapter PROPOSING SOLUTIONS FOR PREVENTING METHANE FIRE AND EXPLOSION IN UNDERGROUND COAL MINES IN QUANG NINH 4.1 MEASURES TO PREVENT DANGER FROM METHANE 4.1.1 Warning of the danger of methane by drilling the mirror for coal digging ovens 18 Figure Schematic layout of exploration drilling holes 4.1.2 Application of portable methane gas measuring devices Figure 10 Image of measuring device, warning of portable methane gas 4.1.3 Application of automatic local monitoring system for high-risk methane mines Hình 11 Sơ đồ khối hệ thống quan trắc 4.2 DYNAMIC MEASURES ELIMINATE THE DANGER OF METHANE To actively eliminate the danger of methane it is necessary to lose the escape of methane by drilling methane gas and discharging it outside the mine Longwall for drilling and removing methane is a coal mine of I-11-5 longwall, 11 seams, Khe Cham coal mine, Ha Long-TKV coal company Methane gas absorbed in boreholes through the pipeline system to remove methane, to process methane gas, has options to choose from * Option Put methane gas on the ground and recover the gas for use; * Option Add methane gas to the ground and release the atmosphere; 19 * Option Discharge the methane gas into the fan station ventilation road.Currently, Khe Cham coal mine is being exploited to -250 to -350, the amount of methane released into the market is unstable so the flow and the amount of methane can be unstable Therefore, it is very costly to invest in the system to absorb and process methane to be able to use it So this topic will not consider option Option Add methane gas to the ground and release it to the atmosphere: Methane gas from under the furnace is guided by the DN200 piping system (line A) through the fire breaker (1) (to separate the underground duct system and on the ground) to the piping with sensing devices installed (2), followed by the gas mixture to the Injector (3) The Injector is equipped with a waste valve (8) for dehydration The gas after passing the Injector (3) is diluted with the blower (4) in the air mixing block (9) before discharging into the atmosphere (B) Noise generated by fans and vacuums is reduced by a silencer (5) The whole working process of the station is operated by the equipment located in the office container (7), in which the installation of dynamic equipment, control and computer system to manage the working process of the system Option Discharge the methane gas into the ventilated kiln of the fan station: Injector (3) by means of compressed air to produce negative low pressure to absorb methane gas from the boreholes according to the DN200 pipeline system (line A) passing through The pipe section has solenoid valve installed (1) and sensor devices, methane gas detector Following the gas mixture is brought to the Injector (3) The gas after passing the Injector (3) is diluted with the exhaust air stream on the ventilated rooftop B Container văn phòng (phòng điều khiển) Cột chống sét Khối trộn không khí Bộ phận giảm âm Tủ động lực, điều khiển thiết bị, đo l-ờng hiển thị Khu vực hòa loãng khí mêtan áp suất Min 0,7MPa Quạt gió Đ-ờng truyền số liệu đo an toàn tia lửa 3 x 400 AC đ-ờng điện nguồn, 35kW Đ-ờng ống khí nÐn Injector dP %CH4 P T Bé ng¾t lưa A Cảm biến áp suất Cảm biến nhiệt độ Cảm biến đo hạ áp Khử n-ớc Nối đất Đ-ờng ống tháo khí mêtan từ d-ới hầm lò lên Đầu đo CH4 0-100% Figure 12 Diagram to bring methane gas to the ground and release the atmosphere 20 PT Van đóng mở Trạm khí nén Đ-ờng ống khí nén mặt đất PT Phòng điều khiển Bảng thị thông số trạm mặt Nút điều khiển van d-ới hầm lò FT Injector Đầu đo CH4, 0-5% Van điện từ phòng nổ DN250 TE PT 10 Đầu đo CH4 0-100% PP A §-êng ống tháo khí mêtan ghi chú: Van điện từ phòng nổ DN250 Đầu đo CH4 0-100% Injector Cảm biến chênh lệch áp suất APR 2000 Ex 2Kpa (FT,PP) Cảm biến nhiệt độ CT-9Ex 1000C (TE) Đầu đo CH4, 0-5% Cảm biến áp suất PC-28 Ex -60 0Pa (PT) Van ®ãng më Cảm biến áp suất PC-28 Ex 1Pa (PT) 10 Chạc ba DN250x2DN80 cho Injector Figure 13 Diagram of methane discharge to fan station ventilation road For option 2: if the methane gas is deposited on the surface, it will increase the installation length of the system and the operating cost of the methane gas testing system, this option should be applied when gas recovery is possible methane to use So choosing option 3: discharging methane gas into the fan station ventilation road is reasonable because it still ensures efficiency and safety in the process of removing methane, low investment cost To check the air flow through the -225 seam, it is possible to dilute the methane gas released by Injector to the furnace line below 0.75%, see the calculation below: - To ensure the safety of the pipeline to remove methane gas must go in the waste wind tunnel, in the stage of deploying the drilling system, removing methane gas to the fan station is the shortest, so selecting the cross-seams of 225 is the location Injector draws air - Air flow through the seam of -225 is 80 m3 / s (4800 m3 / ph), the maximum methane concentration through the seam -225 is 0.3%, so the flow of methane gas passes through the seam -225 are: 0.3x4800 / 100 = 14.4 m3 / ph - The maximum discharge of methane gas is 5.98 m3 / ph, so the total methane flow after the injector discharge of methane is: 14.4 + 5.98 = 20.38 m3 / ph The total amount of wind passing through the seam -225 after the Injector discharge position is: 4800 + 5.98 = 4805.98 m3 / ph - The methane content after the Injector discharge of methane is calculated as the total methane flow divided by the total air flow, instead of calculating the methane content on the cross-section of the -225 after the air discharge Injector position is: 20.38 / 4805.98 x 100% = 0.42% 21 So the air flow through the intermittent -225 can dilute the methane produced by Injector to discharge below the allowable level Conclusion: Choosing the methane treatment option is option 3: Discharge of methane gas into the mine ventilation pathway 4.3 REVIEW CHAPTER Solutions to apply methane explosion prevention and fire prevention in Quang Ninh coal mine and Quang Ninh need to apply a total of solutions such as: Using a bore to advance the mirror with a depth greater than 10m, even hundreds of meters to visit detecting gas bags, containing water, and applying manual methane measurement methods and personal methane alarm equipment equipped for workers in the mine Maintain regular maintenance of methane warning systems currently installed at new mines and installations for areas to prepare for exploitation For reservoirs with high methane gas content, such as seam 11 in Khe Cham coal mine, Ha Long-TKV coal company, it is necessary to take measures to remove gas In the dissertation, the author has calculated for the furnace of I-11-5 market in Khe Cham coal mine to choose a drilling solution to remove gas and discharge it into the waste air stream of the mine with CH4 gas content at the air discharge head is 0, 42% However, if it continues to exploit deeply, the level of natural gas storage in the reservoir increases, it is necessary to continue calculating to connect to the air intake station on the ground to bring methane gas directly to the outdoors CONCLUSIONS AND RECOMMENDATIONS I CONCLUSION From the research results, we can draw the following conclusions: - In general, the tendency of methane storage to increase with the depth of the reservoir as well as the mine - In Quang Ninh coal basin, considering only underground mines, it is also divided into areas with high methane content and lower methane gas storage area - The level of methane escape in the kiln furnace, the furnace prepared in the various technological fluxes are subject to the general rule and the main dependence on methane gas storage and the quantity of longwall mining is: Relative methane emissions and methane emissions absolutely increase as methane gas increases As mining output rises, the methane escaping is absolutely increased, but the relative emissions of methane are reduced From the above aggregate results tables, the methane of the mines from 2007 to 2015 tends to increase next year On the other hand, mines are 22 exploited further and the output of exploitation does not increase much, so it is said that when exploiting deeply, the amount of methane released from the mining areas will increase II RECOMMENDATIONS Increasing the drilling depth to advance the mirror to a minimum of 30m (overcoming cracks due to the impact of blasting), the depth of mirroring can reach hundreds of meters if needed to explore gas and water It is necessary to apply gas removal and drilling for mines with coal seams with high gas storage (class III mines and mines will be promoted to grade III when exploiting deep) Applying the results of the study of predicting methane emissions into reality by taking the results of multiplication forecast with the coefficient k = 0,8651 and plus 0,00246 LIST OF WORKS OF STONE AUTHORS PUBLISHED Nguyễn Văn Thịnh, Đặng Vũ Chí, Nguyễn Cao Khải, Nhữ Việt Tuấn, Ngơ Hồng Ngân (2013), “Dự báo độ chứa khí khí mê tan vỉa than mỏ than Mạo Khê độ sâu khai thác khác nhau”, Tạp chí cơng nghiệp mỏ (5), tr 26-28, 25 Nguyễn Văn Thịnh, Trần Xuân Hà, Nguyễn Cao Khải, Ngô Hoàng Ngân, Vũ Thành Lâm(2013), “Đánh giá xếp hạng mỏ theo độ khí mê tan mỏ than Mơng Dương”, Tạp chí cơng nghiệp mỏ (4), trang 16-18 Nguyễn Văn Thịnh (chủ nhiệm), Nguyễn Văn Quang, Ngô Thái Vinh (2013), Nghiên cứu chế độ chứa, khí mê tan khai thác xuống sâu mỏ than Mạo Khê đề xuất biện pháp phòng ngừa cháy nổ khí mê tan, Đề tài cấp sở mã số T13-30, Trường Đại học Mỏ - Địa chất, Hà Nội Nguyễn Văn Thịnh, Đặng Vũ Chí, Nguyễn Cao Khải (2014), “Đánh giá mức độ chứa khí mê tan khai thác số mỏ than hầm lò khu vực ng Bí- Quảng Ninh”, Tạp chí công nghiệp mỏ (6), trang 13-17 Nguyễn Văn Thịnh (chủ nhiệm), Nguyễn Cao Khải, Đinh Thị Thanh Nhàn (2015), Nghiên cứu độ chứa, khí mê tan độ sâu khai thác khác đề xuất giải pháp phòng ngừa mối nguy hiểm cháy nổ khí số mỏ than hầm lò vùng ng Bí- Quảng Ninh, Đề tài cấp sở mã số T14-25, Trường Đại học Mỏ - Địa chất, Hà Nội Đào Văn Chi, Nguyễn Văn Thịnh, Nguyễn Trọng Phúc(2015), “Giải pháp tháo khí CH4 lò dọc vỉa mức +270 vỉa thiết bị Ekizoster mỏ than Hoành Bồ”, Tạp chí cơng nghiệp mỏ (5), trang 86-89 Nguyen Van Thinh, Dang Vu Chi, Dang Phuong Thao, Pham Thi Nhung, Tran Anh Duong (2017), “Methane forecast in the coal seams of Quang Hanh underground coal mine”, International Conferentce on Geo-spatial 23 Technologies and Earth Resources-HaNoi 2017, ISBN978-604-913-618-4, pages 487-492 Van Thinh Nguyen, Waldemar Mijał, Vu Chi Dang (2017), “Methane estimation in DuongHuy coal mine”, 4th International conference scientificresearch cooperation between Vietnam and Poland, E3S Web of Conferences 35, 01005 s(2018) https://doi.org/10.1051/e3sconf/20183501005 POL-VIET 2017 Van Thinh Nguyen (2018), “Determination of Methane Content at Hongthai Coal Mine from Curent Mining To -150 Level in Vietnam”, International Journal of Latest Engineering and Management Research (IJLEMR), ISSN: 2455-4847, www.ijlemr.com || Volume 03 - Issue 08 || August 2018 ||PP.65-71 10 Nguyễn Văn Thịnh (2018), “Xác định độ chứa khí mê tan vỉa than mỏ than Mông Dương đến mức -350”, Tạp chí cơng nghiệp mỏ (4), trang 24-27 11 Nguyễn Văn Thịnh, Đặng Vũ Chí, Đặng Phương Thảo(2018), “Nghiên cứu yếu tố ảnh hưởng đến độ khí mê tan gương lò đào mỏ than Khe Chàm 1”, Tạp chí cơng nghiệp mỏ (6), trang 21-26 ... b Statistical method of the Soviet Union The basis of this method is the system of statistic data in the past in terms of air discharge of the mining area or exploitation floor and other factors... methane content after the Injector discharge of methane is calculated as the total methane flow divided by the total air flow, instead of calculating the methane content on the cross-section of the... CHARACTERRISTICS OF METHANE STORAGE IN COAL SEAMS The concentration of methane is the amount of methane gas calculated according to the standard conditions in ton of combustion coal block The determinant