Pub Date : 2022-02-28DOI: 10.46326/jmes.2022.63(1).03
N. B. Pham, N. Tran, Dong Trung Tran, Oanh T. K. Tran
Sediment depositional environments are one of the important scientific bases in evaluation the reservoir potential of sedimentary rocks. This article focuses on studying this issue for Middle Miocene sediments, Thien Ung - Mang Cau structure, Block 04 - 3, Nam Con Son basin. The article has integrated the methods of well log interpretation, thin section analysis and seismic attribute analysis, combined with the results of paleontological analysis of VPI - Labs to identify depositional environments of Middle Miocene sediments in the case study area. The results of interpreting well log data show that the Middle Miocene sediments were deposited in the following environments: shallow marine, shoreline, mouth bars, delta front, prodelta and lower deltaic plain. These findings are also consistent with the results of petrographic and paleontological analysis. The results of petrographic analysis show that in the study area, there are 2 main groups of sedimentary rocks, which are clastic and carbonate rocks. In the thin sections, the following components were detected: glauconite clay is characterized of marine environment, carbonate fission and siderite ore which are characteristic of deltaic environments. While paleontological samples detected organic materials, such as algae, bitumen; and fossils such as Foraminifera, Da Gai and Oc Gai - typical for shallow marine environments. The results of the seismic attribute analysis for the Middle Miocene carbonate sediments of the structure have clarified that the carbonate is concentrated in the central and eastern uplift area. This distribution tends to fewer in the west. This finding is consistent when the authors compared to well correlation in the area (wells: C - 1X, C - 2X, C - 3X and C - 4X) and also logically with the sedimentary principles.
{"title":"Depositional Environment Assessment of the Middle Miocene Sedimentary Rocks in Thien Ung - Mang Cau Structure, Block 04 - 3, Nam Con Son Basin","authors":"N. B. Pham, N. Tran, Dong Trung Tran, Oanh T. K. Tran","doi":"10.46326/jmes.2022.63(1).03","DOIUrl":"https://doi.org/10.46326/jmes.2022.63(1).03","url":null,"abstract":"Sediment depositional environments are one of the important scientific bases in evaluation the reservoir potential of sedimentary rocks. This article focuses on studying this issue for Middle Miocene sediments, Thien Ung - Mang Cau structure, Block 04 - 3, Nam Con Son basin. The article has integrated the methods of well log interpretation, thin section analysis and seismic attribute analysis, combined with the results of paleontological analysis of VPI - Labs to identify depositional environments of Middle Miocene sediments in the case study area. The results of interpreting well log data show that the Middle Miocene sediments were deposited in the following environments: shallow marine, shoreline, mouth bars, delta front, prodelta and lower deltaic plain. These findings are also consistent with the results of petrographic and paleontological analysis. The results of petrographic analysis show that in the study area, there are 2 main groups of sedimentary rocks, which are clastic and carbonate rocks. In the thin sections, the following components were detected: glauconite clay is characterized of marine environment, carbonate fission and siderite ore which are characteristic of deltaic environments. While paleontological samples detected organic materials, such as algae, bitumen; and fossils such as Foraminifera, Da Gai and Oc Gai - typical for shallow marine environments. The results of the seismic attribute analysis for the Middle Miocene carbonate sediments of the structure have clarified that the carbonate is concentrated in the central and eastern uplift area. This distribution tends to fewer in the west. This finding is consistent when the authors compared to well correlation in the area (wells: C - 1X, C - 2X, C - 3X and C - 4X) and also logically with the sedimentary principles.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129010567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.46326/jmes.2022.63(1).07
D. N. Vo, C. Le, D. T. Nguyen, T. Nguyen
In Vietnam, coal mines are exploited deeper and deeper, and the method of seams opening using with mine shafts has been increasingly popular. For mine surveying, there are several methods of conveying the bearing to the tunnels, depending on the number of mine shafts, the depth and the cross-section of the shaft, and the available surveyring equipment of the mine. Each method has its advantages and disadvantages, and different application conditions. It has been proved that the method of conveying the bearing to the tunnels or underground orientation by traditional methods gives low accuracy, requires a lot of time and effort, and no assurance of accuracy. The method using a gyrotheodolite has the advantages of reducing time and effort and improving the level of safety. Therefore, the application of surveying gyro is considered as an effective alternative in this work. The paper presents the results of the application of a GYRO X II gyrotheodolite in determining bearings at -140 m and -350 m of the Nui Beo coal mine in order to improve orientation accuracy. The resulting bearings of the first lines of the 2-level underground traversing control networks were used to determine control points at the -140 m level and the -350 m level. The results proved the accuracy of the method with the biggest azimuth error of 9.23”, meeting the accuracy requirement of the Vietnamese standard for mine surveying.
{"title":"Application of gyrotheodolites in the determination of bearings for the hozirontal control network of Nui Beo underground coal mine","authors":"D. N. Vo, C. Le, D. T. Nguyen, T. Nguyen","doi":"10.46326/jmes.2022.63(1).07","DOIUrl":"https://doi.org/10.46326/jmes.2022.63(1).07","url":null,"abstract":"In Vietnam, coal mines are exploited deeper and deeper, and the method of seams opening using with mine shafts has been increasingly popular. For mine surveying, there are several methods of conveying the bearing to the tunnels, depending on the number of mine shafts, the depth and the cross-section of the shaft, and the available surveyring equipment of the mine. Each method has its advantages and disadvantages, and different application conditions. It has been proved that the method of conveying the bearing to the tunnels or underground orientation by traditional methods gives low accuracy, requires a lot of time and effort, and no assurance of accuracy. The method using a gyrotheodolite has the advantages of reducing time and effort and improving the level of safety. Therefore, the application of surveying gyro is considered as an effective alternative in this work. The paper presents the results of the application of a GYRO X II gyrotheodolite in determining bearings at -140 m and -350 m of the Nui Beo coal mine in order to improve orientation accuracy. The resulting bearings of the first lines of the 2-level underground traversing control networks were used to determine control points at the -140 m level and the -350 m level. The results proved the accuracy of the method with the biggest azimuth error of 9.23”, meeting the accuracy requirement of the Vietnamese standard for mine surveying.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"31 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134510378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.46326/jmes.2022.63(1).04
A. H. Nguyen, D. Nguyen
The evaluations of properties of carbonate reservoirs containing gas with very high carbon dioxide (CO2) content often face many difficulties. In fact, there is a significal difference in interpretation results compared to conventional gas well testing due to: there is a gas to liquid phase transition; noise, abnormal increase or decrease in pressure and temperature during flow period, etc. These abnormal behaviors are all directly related to the specificity of CO2 properties with high compressible than that of natural gas, which can vary greatly density and can reach supercritical liquid state, transitioning solid to liquid or liqid to gaseous states even when pressure and temperature changes within a small range. During the testing of gas wells with high CO2 content, the phenomenon of pressure drop while pressure buid-up often occurs, leading to the analysis of reservoir parameters according to the conventional pressure build-up analysis method usually not feasible. The content of the article is aimed at researching and applying the method of interpreting well test data in the drawdown period while multi-rate flowing to more accurately estimate reservoir properties and mitigate risks in the design of the field development plan to achieve the economic efficiency.
{"title":"Well - test analysis for wells with gas rich CO2 in carbonate reservoir Song Hong Basin","authors":"A. H. Nguyen, D. Nguyen","doi":"10.46326/jmes.2022.63(1).04","DOIUrl":"https://doi.org/10.46326/jmes.2022.63(1).04","url":null,"abstract":"The evaluations of properties of carbonate reservoirs containing gas with very high carbon dioxide (CO2) content often face many difficulties. In fact, there is a significal difference in interpretation results compared to conventional gas well testing due to: there is a gas to liquid phase transition; noise, abnormal increase or decrease in pressure and temperature during flow period, etc. These abnormal behaviors are all directly related to the specificity of CO2 properties with high compressible than that of natural gas, which can vary greatly density and can reach supercritical liquid state, transitioning solid to liquid or liqid to gaseous states even when pressure and temperature changes within a small range. During the testing of gas wells with high CO2 content, the phenomenon of pressure drop while pressure buid-up often occurs, leading to the analysis of reservoir parameters according to the conventional pressure build-up analysis method usually not feasible. The content of the article is aimed at researching and applying the method of interpreting well test data in the drawdown period while multi-rate flowing to more accurately estimate reservoir properties and mitigate risks in the design of the field development plan to achieve the economic efficiency.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124345726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-31DOI: 10.46326/jmes.2021.62(6).03
H. M. Nguyen, A. Le, Muoi Nguyen, N. Bui
The Cuu Long basin is an Early Tertiary rift basin of southern Vietnam, and the most potential basin in the country with high productive for oil and gas. Special interest in the Lower Miocene reservoir in the Cuu Long basin is caused by the gradual depletion of unique oil-bearing in the fractured basement and the possibility of transferring production wells to overlying deposits in the terrigenous rocks of the sedimentary cover and entering new deposits into development. In recent years, seismic attributes analysis has emerged as an effective tool to predict ancient riverbeds where sand bodies may exist in nonstructural traps. Understanding the distribution of these sand bodies will be of great significance in the orientation of oil and gas exploration activities. The paper applied seismic attribute analysis method combined with artificial neural network (ANN) and well data to predict the distribution of sandstones reservoirs of Lower Miocene sediments in the Northeastern Bach Ho oil field. Seismic attributes selected as input for ANN training including Relative Acoustic Impedance, Root Mean Square, Sweetness. The attributes provide the most obvious opportunity to display geological features with varying seismic amplitude characteristics as well as predict lithofacies, petrology and the distribution of sand bodies. The research results have identified the potential reservoirs in the Northeastern area of Bach Ho field, which are deposited in the fluvial, marginal lacustrine and deltaic environments.
{"title":"Application of seismic attribute analysis in Lower Miocene reservoir characterization, northeast Bach Ho field, Vietnam","authors":"H. M. Nguyen, A. Le, Muoi Nguyen, N. Bui","doi":"10.46326/jmes.2021.62(6).03","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(6).03","url":null,"abstract":"The Cuu Long basin is an Early Tertiary rift basin of southern Vietnam, and the most potential basin in the country with high productive for oil and gas. Special interest in the Lower Miocene reservoir in the Cuu Long basin is caused by the gradual depletion of unique oil-bearing in the fractured basement and the possibility of transferring production wells to overlying deposits in the terrigenous rocks of the sedimentary cover and entering new deposits into development. In recent years, seismic attributes analysis has emerged as an effective tool to predict ancient riverbeds where sand bodies may exist in nonstructural traps. Understanding the distribution of these sand bodies will be of great significance in the orientation of oil and gas exploration activities. The paper applied seismic attribute analysis method combined with artificial neural network (ANN) and well data to predict the distribution of sandstones reservoirs of Lower Miocene sediments in the Northeastern Bach Ho oil field. Seismic attributes selected as input for ANN training including Relative Acoustic Impedance, Root Mean Square, Sweetness. The attributes provide the most obvious opportunity to display geological features with varying seismic amplitude characteristics as well as predict lithofacies, petrology and the distribution of sand bodies. The research results have identified the potential reservoirs in the Northeastern area of Bach Ho field, which are deposited in the fluvial, marginal lacustrine and deltaic environments.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116270036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-31DOI: 10.46326/jmes.2021.62(6).01
F. Rahal, F. Z. B. Hamed, M. Hadjel
Satellite images have a remarkable ability to help researchers map the distribution and detect the nature of the soil exposed on the earth's surface. The remote-sensing mapping of clayey soils makes it possible to determine their shrinking-swelling potentials. This approach is helpful in analyzing large areas where the traditional sampling approach with laboratory analysis is expensive. This high cost often leads to a limited number of samples and thus to a poor representation of a site with an underestimation of the presence of swelling soils. The Sidi - Chahmi area is representative of this type of soil. In addition, it is an area that undergoes the substantial urban sprawl of the city of Oran. The urbanization of this area is under the risk of clay-type soil movements, the identification of which by satellite imagery may help mitigate shrink-swell risk. EO-1-Hyperion hyperspectral images, whose effectiveness has already been proven for mapping clay minerals, were used to identify minerals such as illite, montmorillonite, and kaolinite in the Sidi - Chahmi area.
{"title":"Mapping of clay soils exposed to the shrinking - swelling phenomenon, with EO - 1 - Hyperion data in the region of Sidi - Chahmi, Algeria","authors":"F. Rahal, F. Z. B. Hamed, M. Hadjel","doi":"10.46326/jmes.2021.62(6).01","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(6).01","url":null,"abstract":"Satellite images have a remarkable ability to help researchers map the distribution and detect the nature of the soil exposed on the earth's surface. The remote-sensing mapping of clayey soils makes it possible to determine their shrinking-swelling potentials. This approach is helpful in analyzing large areas where the traditional sampling approach with laboratory analysis is expensive. This high cost often leads to a limited number of samples and thus to a poor representation of a site with an underestimation of the presence of swelling soils. The Sidi - Chahmi area is representative of this type of soil. In addition, it is an area that undergoes the substantial urban sprawl of the city of Oran. The urbanization of this area is under the risk of clay-type soil movements, the identification of which by satellite imagery may help mitigate shrink-swell risk. EO-1-Hyperion hyperspectral images, whose effectiveness has already been proven for mapping clay minerals, were used to identify minerals such as illite, montmorillonite, and kaolinite in the Sidi - Chahmi area.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133898667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-31DOI: 10.46326/jmes.2021.62(6).07
Ngoc-anh Pham, P. Osiński, N. Do, E. Koda, M. V. Nguyen, D. Bui, Ngan Van Tao
The rapid economic development of Vietnam triggers a number of challenges in all sectors including infrastructure design and execution. New development plans and lack of space in densely populated and economically valuable areas creates a need for complex engineering solutions to meet the demand. The present research is a case study investigating reengineered vast natural slope to meet all requirements for geotechnical safety such as maximum displacements and factor of safety. Complex ground conditions and significant dimensions of the slope made the entire structure very likely to cause major risk for the future development plan of the site. Due to complex conditions, the slope was divided into 4 main sections. Each section was reinforced using a combination of soil nails, ground anchors, drainage systems and micro piles, of 19m for a single pile. Due to very much limited space available new geometry of the slope was designed for inclination reaching 1:0.3. Based on numerical modelling and computation the results revealed that the maximum lateral displacements felt in a range of 37-50x10-3 m and the factor of safety was 1.56-1.65, depending on a section and analysed scenario. The computations allowed proposing combined geotechnical solutions for very much challenging sites, assuring high safety standards and fitting the entire design within a limited available area.
{"title":"Numerical modeling of slope stability incorporating complex reinforcement solution in high-risk failure area- unusual case study","authors":"Ngoc-anh Pham, P. Osiński, N. Do, E. Koda, M. V. Nguyen, D. Bui, Ngan Van Tao","doi":"10.46326/jmes.2021.62(6).07","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(6).07","url":null,"abstract":"The rapid economic development of Vietnam triggers a number of challenges in all sectors including infrastructure design and execution. New development plans and lack of space in densely populated and economically valuable areas creates a need for complex engineering solutions to meet the demand. The present research is a case study investigating reengineered vast natural slope to meet all requirements for geotechnical safety such as maximum displacements and factor of safety. Complex ground conditions and significant dimensions of the slope made the entire structure very likely to cause major risk for the future development plan of the site. Due to complex conditions, the slope was divided into 4 main sections. Each section was reinforced using a combination of soil nails, ground anchors, drainage systems and micro piles, of 19m for a single pile. Due to very much limited space available new geometry of the slope was designed for inclination reaching 1:0.3. Based on numerical modelling and computation the results revealed that the maximum lateral displacements felt in a range of 37-50x10-3 m and the factor of safety was 1.56-1.65, depending on a section and analysed scenario. The computations allowed proposing combined geotechnical solutions for very much challenging sites, assuring high safety standards and fitting the entire design within a limited available area.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123619028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-31DOI: 10.46326/jmes.2021.62(6).08
Duy Van Pham, D. T. Le, Son Anh Do
This paper presents a technical solution for reducing methane gas concentration (degasification) caused by a high methane-emitted coal seam at Mao Khe coal mine - Vinacomin. The technique is implemented by drilling a long borehole from the footwall of the roadway into the coal seam and punching small holes along the borehole for gas release. A field study at the longwall level -150/-80 m at Seam 9 of Mao Khe coal mine shows that after the degasification, the gas concentration here is lowered to safety standards. The technique can be used for all coal seams ranked as Class II, Class III, and super-class regarding methane gas, minimizing the risk of methane combustion and explosion.
{"title":"Degasification of methane for high methane-emitted coal seam at Mao Khe coal mine - Vinacomin by drilling long borehole","authors":"Duy Van Pham, D. T. Le, Son Anh Do","doi":"10.46326/jmes.2021.62(6).08","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(6).08","url":null,"abstract":"This paper presents a technical solution for reducing methane gas concentration (degasification) caused by a high methane-emitted coal seam at Mao Khe coal mine - Vinacomin. The technique is implemented by drilling a long borehole from the footwall of the roadway into the coal seam and punching small holes along the borehole for gas release. A field study at the longwall level -150/-80 m at Seam 9 of Mao Khe coal mine shows that after the degasification, the gas concentration here is lowered to safety standards. The technique can be used for all coal seams ranked as Class II, Class III, and super-class regarding methane gas, minimizing the risk of methane combustion and explosion.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126583628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.46326/jmes.2021.62(5a).08
Hiep Hoang Do, Tung Manh Bui, D. Vu, Anh Tuan Tran
The mechanization of longwall mining is an inevitable trend in underground coal industry. At present, Vietnam has operated many mechanized longwall faces in Quang Ninh coal field. The mechanised longwall at Seam 11, Centre area Duong Huy coal mine has been operated and its mechanised equipment complex basically performs as designed. However, the actual production shows that the longwall equipment has not reached its maximum capacity while the arrangement of production remains inadequate. Apart from objective factors, the initial production arrangement chart did not consider the maximization of the mechanised complex. In this paper, the authors used field observation and theoretical methods for improvement of production arrangement chart for the mechanised longwall at Seam 11, Duong Huy coal mine. An improved chart of production arrangement (and subsequently a chart of labour arrangement) has been developed based on actual time cost for each production task. According to the new chart, the production can be now implemented with 7 cuts per day - night. This arrangement well corresponds with practical production capacity that increases the longwall productivity.
{"title":"Improvement of production arrangement chart for mechanised longwall at Seam 11 of Centre area - Duong Huy coal mine","authors":"Hiep Hoang Do, Tung Manh Bui, D. Vu, Anh Tuan Tran","doi":"10.46326/jmes.2021.62(5a).08","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(5a).08","url":null,"abstract":"The mechanization of longwall mining is an inevitable trend in underground coal industry. At present, Vietnam has operated many mechanized longwall faces in Quang Ninh coal field. The mechanised longwall at Seam 11, Centre area Duong Huy coal mine has been operated and its mechanised equipment complex basically performs as designed. However, the actual production shows that the longwall equipment has not reached its maximum capacity while the arrangement of production remains inadequate. Apart from objective factors, the initial production arrangement chart did not consider the maximization of the mechanised complex. In this paper, the authors used field observation and theoretical methods for improvement of production arrangement chart for the mechanised longwall at Seam 11, Duong Huy coal mine. An improved chart of production arrangement (and subsequently a chart of labour arrangement) has been developed based on actual time cost for each production task. According to the new chart, the production can be now implemented with 7 cuts per day - night. This arrangement well corresponds with practical production capacity that increases the longwall productivity.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116755964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.46326/jmes.2021.62(5a).11
C. Dao, H. Tran, Q. Nguyen
During the coal mining period in the fourth quarter of 2020, the air temperature increased in mining areas and the survey results on the current state of the longwall 14.5.20 at Khe Cham III coal mine, showed that the air temperature rises to 320C and exceeded the permit regulation (300C) of QCVN 01/2011/BCT. To a nalyze the relationship between oxygen adsorption capacity and temperature in coal samples, coal samples were taken at the head and bottom of the coalface. The result shows that the oxygen adsorption constant U25 = 0.0032 is the largest in the coal samples, while the Russian standard for self-ignition of coal is U25 ≥ 0.016. Therefore, the coal samples of Khe Cham III coal mine are low self-ignition. Thus, it can be seen that the causes leading to the increase in temperature in the longwall 14.5.20 due to the compression of the road ventilation, the only measured airflow is 7.68 m3/s, while the required airflow is 16 m3/s. On the other hand, due to the influence of thermal radiation from the surrounding rock, the area has finished mining on the longwall and the road is narrow lead to the airflow is not small enough to carry this heat out. To ensure safety in the mining process when there are signs of increasing temperature from the mining areas. The article proposed solutions to complete the ventilation system; drilling and pumping water into the coal face; construct walls to isolate the exploited area to prevent oxidation of coal and temperature in the goaf spread to longwall.
{"title":"Analyze the causes and propose solutions to prevent an increased temperature of the longwall in Khe Cham III coal mine","authors":"C. Dao, H. Tran, Q. Nguyen","doi":"10.46326/jmes.2021.62(5a).11","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(5a).11","url":null,"abstract":"During the coal mining period in the fourth quarter of 2020, the air temperature increased in mining areas and the survey results on the current state of the longwall 14.5.20 at Khe Cham III coal mine, showed that the air temperature rises to 320C and exceeded the permit regulation (300C) of QCVN 01/2011/BCT. To a nalyze the relationship between oxygen adsorption capacity and temperature in coal samples, coal samples were taken at the head and bottom of the coalface. The result shows that the oxygen adsorption constant U25 = 0.0032 is the largest in the coal samples, while the Russian standard for self-ignition of coal is U25 ≥ 0.016. Therefore, the coal samples of Khe Cham III coal mine are low self-ignition. Thus, it can be seen that the causes leading to the increase in temperature in the longwall 14.5.20 due to the compression of the road ventilation, the only measured airflow is 7.68 m3/s, while the required airflow is 16 m3/s. On the other hand, due to the influence of thermal radiation from the surrounding rock, the area has finished mining on the longwall and the road is narrow lead to the airflow is not small enough to carry this heat out. To ensure safety in the mining process when there are signs of increasing temperature from the mining areas. The article proposed solutions to complete the ventilation system; drilling and pumping water into the coal face; construct walls to isolate the exploited area to prevent oxidation of coal and temperature in the goaf spread to longwall.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126507614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.46326/jmes.2021.62(5a).02
Tung Manh Bui, H. Nguyen, T. Nguyen
Longwall Top Coal Caving (LTCC) technology with great cutting height is a new development trend in mining thick coal seam. The cutting height of LTCC face typically ranges from 2.8 m to 3.2 m in many coal mining countvies, but it recently reaches up to 4.2 m in many coal mines in China. Because the cutting height increases, the caving height accordingly decreases that changes the stress distribution around coal face and law of roof rock caving. Based on the geological condition of Longwall 4108 at Ping Shou coal mine, ShanXi province, China, this paper presents a modelling of LTCC mining process with a cutting height of 4.2 m by using the numerical program FLAC3D. From the modelling, the paper presents an analysis of stress distribution ahead of LTCC face with great cutting height. The results show that as the coal face advances, the stress magnitude ahead of coal face increases. The peak front abutment stress moves further away from coal face. The stress concentration ratio increases, and stress concentration zone expands correspondingly. These changes of stress facilitate the failure of top coal, increasing the efficiency of top coal recovery and improving longwall face stability.
{"title":"Stress distribution ahead of mechanized longwall top coal caving face with great cutting height","authors":"Tung Manh Bui, H. Nguyen, T. Nguyen","doi":"10.46326/jmes.2021.62(5a).02","DOIUrl":"https://doi.org/10.46326/jmes.2021.62(5a).02","url":null,"abstract":"Longwall Top Coal Caving (LTCC) technology with great cutting height is a new development trend in mining thick coal seam. The cutting height of LTCC face typically ranges from 2.8 m to 3.2 m in many coal mining countvies, but it recently reaches up to 4.2 m in many coal mines in China. Because the cutting height increases, the caving height accordingly decreases that changes the stress distribution around coal face and law of roof rock caving. Based on the geological condition of Longwall 4108 at Ping Shou coal mine, ShanXi province, China, this paper presents a modelling of LTCC mining process with a cutting height of 4.2 m by using the numerical program FLAC3D. From the modelling, the paper presents an analysis of stress distribution ahead of LTCC face with great cutting height. The results show that as the coal face advances, the stress magnitude ahead of coal face increases. The peak front abutment stress moves further away from coal face. The stress concentration ratio increases, and stress concentration zone expands correspondingly. These changes of stress facilitate the failure of top coal, increasing the efficiency of top coal recovery and improving longwall face stability.","PeriodicalId":170167,"journal":{"name":"Journal of Mining and Earth Sciences","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128351424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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