Pub Date : 2023-07-20DOI: 10.24425/AMS.2020.133192
V. Alabiev, A. Dozorov, I. Savvateeva, V. Druzyanova, M. Sangadzhiev
The purpose of this research is to substantiate a technical solution for improving the working condi- tions for the thermal factor in the extraction of oil by the thermoshaft method using the mine refrigeration technology. The review of manufacturers and technical characteristics of refrigeration technology in Russia, CIS countries and Western Europe was conducted. It was shown that the use of a water cooling machine in the mine air conditioning system will reduce the air temperature in the oil production gallery to the required values and will allow to abandon the long-term construction of a surface stationary refrigeration station. Normalization of the thermal regime reduces the costs of benefits and compensation for work in harmful labor conditions and improves the quality of service of production wells by operators. The practical significance is that the proposed project for the introduction of air conditioning has a high level of profitability, and its payoff will occur in the second year of operation.
{"title":"Economic Practicability of the Implementation of the Mine Refrigeration Technology for Normalization of Thermal Conditions","authors":"V. Alabiev, A. Dozorov, I. Savvateeva, V. Druzyanova, M. Sangadzhiev","doi":"10.24425/AMS.2020.133192","DOIUrl":"https://doi.org/10.24425/AMS.2020.133192","url":null,"abstract":"The purpose of this research is to substantiate a technical solution for improving the working condi- tions for the thermal factor in the extraction of oil by the thermoshaft method using the mine refrigeration technology. The review of manufacturers and technical characteristics of refrigeration technology in Russia, CIS countries and Western Europe was conducted. It was shown that the use of a water cooling machine in the mine air conditioning system will reduce the air temperature in the oil production gallery to the required values and will allow to abandon the long-term construction of a surface stationary refrigeration station. Normalization of the thermal regime reduces the costs of benefits and compensation for work in harmful labor conditions and improves the quality of service of production wells by operators. The practical significance is that the proposed project for the introduction of air conditioning has a high level of profitability, and its payoff will occur in the second year of operation.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46064113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/AMS.2018.124983
K. Skrzypkowski, W. Korzeniowski, Katarzyna POBORSKA-MŁYNARSKA, Scalonych Próbek
Based on laboratory tests of selected properties of secondary waste (ashes and dusts) from municipal waste incineration plants, the possibility of recovering some properties of waste in the process of filling the post-mining voids in the salt mine was assessed. The furnace bottom ash and the waste from the flue gas treatment from one of the national incineration plants were examined. The grain curves of dry waste and the density of the prepared mixtures were characterized. Twelve variants of the compositions of ash-based mixtures with varying proportions of the individual components were considered, taking into account both fresh water and brine. For each variant of the composition, the amount of redundant liquid appeared as well as the time of solidifying of the mixture to a certain strength and the compressibility values obtained. Considering the possibility of transporting mixtures in mines by means of pipelines at relatively long distances, and allowing the filling of large salt chambers to be filled and evenly filled, flow parameters were determined. In addition, the permeability of solidified waste samples was investigated, showing the potential for reducing the strength of the waste mass due to the action of water or brine. The technical feasibility of eliminating redundant liquid in the binding process has been confirmed, which is particularly important in salt mines. Preliminary values for the amount of binder (5%÷10%) to be added to the mixtures to obtain the specified strength properties of the artificially formed mass at Rc = 0.5 MPa. Attention was paid to the important practical aspect resulting from the rapid increase of this type of waste in the comming years in Poland and at the same time vast potential for their use in salt mining, where we have a huge capacity of salt chambers available.
{"title":"Binding Capability of Ashes and Dusts from Municipal Solid Waste Incineration with Salt Brine and Geotechnical Parameters of the Cemented Samples","authors":"K. Skrzypkowski, W. Korzeniowski, Katarzyna POBORSKA-MŁYNARSKA, Scalonych Próbek","doi":"10.24425/AMS.2018.124983","DOIUrl":"https://doi.org/10.24425/AMS.2018.124983","url":null,"abstract":"Based on laboratory tests of selected properties of secondary waste (ashes and dusts) from municipal waste incineration plants, the possibility of recovering some properties of waste in the process of filling the post-mining voids in the salt mine was assessed. The furnace bottom ash and the waste from the flue gas treatment from one of the national incineration plants were examined. The grain curves of dry waste and the density of the prepared mixtures were characterized. Twelve variants of the compositions of ash-based mixtures with varying proportions of the individual components were considered, taking into account both fresh water and brine. For each variant of the composition, the amount of redundant liquid appeared as well as the time of solidifying of the mixture to a certain strength and the compressibility values obtained. Considering the possibility of transporting mixtures in mines by means of pipelines at relatively long distances, and allowing the filling of large salt chambers to be filled and evenly filled, flow parameters were determined. In addition, the permeability of solidified waste samples was investigated, showing the potential for reducing the strength of the waste mass due to the action of water or brine. The technical feasibility of eliminating redundant liquid in the binding process has been confirmed, which is particularly important in salt mines. Preliminary values for the amount of binder (5%÷10%) to be added to the mixtures to obtain the specified strength properties of the artificially formed mass at Rc = 0.5 MPa. Attention was paid to the important practical aspect resulting from the rapid increase of this type of waste in the comming years in Poland and at the same time vast potential for their use in salt mining, where we have a huge capacity of salt chambers available.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47661997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/ams.2020.134139
A. Walentek, Krystian Wierzbiński
In longwall absolute methane emission rate forecasting, the range of the destressing zone is determined empirically and is not considered to be dependent on the geomechanical parameters of the rock strata. This simplification regarding destressing zone determination may result in significant differences between the forecast and the actual methane emission rates. During the extraction of coal seams using a system involving longwalls with caving under the conditions of low rock mass geomechanical parameters, the absolute methane emission rate forecasts are typically underestimated in comparison to the actual methane emission rates. In order to examine the influence of the destressing zones on the final forecasting result and to assess the influence of the rock mass geomechanical parameters on the increased accuracy of forecast values, destressing zones were determined for three longwalls with lengths ranging from 186 to 250 m, based on numerical modelling using the finite difference method (FDM). The modelling results confirmed the assumptions concerning the upper destressing zone range adopted for absolute methane emission rate forecasting. As for the remaining parameters, the destressing zones yielded great differences, particularly for floor strata. To inspect the accuracy of the FDM calculation result, an absolute methane emission rate forecasting algorithm was supplemented with the obtained zones. The prepared forecasts, both for longwall methane emission rates as well as the inflow of methane to the longwalls from strata within the destressing zone, were verified via underground methane emission tests. A comparative analysis found that including geomechanical parameters in methane emission rate forecasting can significantly reduce the errors in forecast values.
{"title":"Influence of Rock Geomechanical Parameters on Increased Longwall Absolute Methane Emission Rate Forecasting Accuracy","authors":"A. Walentek, Krystian Wierzbiński","doi":"10.24425/ams.2020.134139","DOIUrl":"https://doi.org/10.24425/ams.2020.134139","url":null,"abstract":"In longwall absolute methane emission rate forecasting, the range of the destressing zone is determined empirically and is not considered to be dependent on the geomechanical parameters of the rock strata. This simplification regarding destressing zone determination may result in significant differences between the forecast and the actual methane emission rates. During the extraction of coal seams using a system involving longwalls with caving under the conditions of low rock mass geomechanical parameters, the absolute methane emission rate forecasts are typically underestimated in comparison to the actual methane emission rates. In order to examine the influence of the destressing zones on the final forecasting result and to assess the influence of the rock mass geomechanical parameters on the increased accuracy of forecast values, destressing zones were determined for three longwalls with lengths ranging from 186 to 250 m, based on numerical modelling using the finite difference method (FDM). The modelling results confirmed the assumptions concerning the upper destressing zone range adopted for absolute methane emission rate forecasting. As for the remaining parameters, the destressing zones yielded great differences, particularly for floor strata. To inspect the accuracy of the FDM calculation result, an absolute methane emission rate forecasting algorithm was supplemented with the obtained zones. The prepared forecasts, both for longwall methane emission rates as well as the inflow of methane to the longwalls from strata within the destressing zone, were verified via underground methane emission tests. A comparative analysis found that including geomechanical parameters in methane emission rate forecasting can significantly reduce the errors in forecast values.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47869253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/AMS.2019.129367
Xiufeng Zhang, Ganqiang Tao, Zhonghua Zhu
The draw theory is the foundation for decreasing ore loss and dilution indices while extracting deposits from mines. Therefore, research on draw theory is of great significance to optimally guide the draw control and improve the economy efficiency of mines. The laboratory scaled physical draw experiments under inclined wall condition conducted showed that a new way was proposed to investigate the flow zone of granular materials. The flow zone was simply divided into two parts with respect to the demarcation point of the flow axis. Based on the stochastic medium draw theory, theoretical movement formulas were derived to define the gravity flow of fragmented rocks in these two parts. The ore body with 55° dip and 10 m width was taken as an example, the particle flow parameters were fitted, and the corresponding theoretical shape of the draw body was sketched based on the derived equation of draw-body shape. The comparison of experimental and theoretical shapes of the draw body confirmed that they coincided with each other; hence, the reliability of the derived equation of particle motion was validated.
{"title":"A Gravity Flow Model of Fragmented Rocks in Longitudinal Sublevel Caving of Inclined Medium-Thick Ore Bodies","authors":"Xiufeng Zhang, Ganqiang Tao, Zhonghua Zhu","doi":"10.24425/AMS.2019.129367","DOIUrl":"https://doi.org/10.24425/AMS.2019.129367","url":null,"abstract":"The draw theory is the foundation for decreasing ore loss and dilution indices while extracting deposits from mines. Therefore, research on draw theory is of great significance to optimally guide the draw control and improve the economy efficiency of mines. The laboratory scaled physical draw experiments under inclined wall condition conducted showed that a new way was proposed to investigate the flow zone of granular materials. The flow zone was simply divided into two parts with respect to the demarcation point of the flow axis. Based on the stochastic medium draw theory, theoretical movement formulas were derived to define the gravity flow of fragmented rocks in these two parts. The ore body with 55° dip and 10 m width was taken as an example, the particle flow parameters were fitted, and the corresponding theoretical shape of the draw body was sketched based on the derived equation of draw-body shape. The comparison of experimental and theoretical shapes of the draw body confirmed that they coincided with each other; hence, the reliability of the derived equation of particle motion was validated.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44254043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/ams.2019.126281
M. Rotkegel
Steel arch-rectangular support has a wide range of applications in Polish coal mines due to its asymmetrical shape. The frame has an arched outline on one side of the side wall, while on the opposite side it is rectangular. As a result, the support is ideal for securing set up room and recovery room. It can also be successfully used to secure three-way intersections of underground workings. To a large extent, however, the importance of these advantages is diminished by relatively low load-bearing parameters, resulting from a partially straight canopy, as well as the asymmetrical distribution of the load acting on the support in underground conditions. In order to ensure the proper and optimal operation of such frames, in addition to the standard requirements for roof supports, additional conditions must be met. The basic requirement is to support the end of the canopy on the corner of the excavation. This article presents examples of arch-rectangular supports, their applications as well as laboratory tests and strength analysis of the frames and its elements. These tests allowed the requirements regarding the construction of the frame, the selection of the support and the conditions of building in the excavation to be specified.
{"title":"The conditions for proper operation of the arch-rectangular support","authors":"M. Rotkegel","doi":"10.24425/ams.2019.126281","DOIUrl":"https://doi.org/10.24425/ams.2019.126281","url":null,"abstract":"Steel arch-rectangular support has a wide range of applications in Polish coal mines due to its asymmetrical shape. The frame has an arched outline on one side of the side wall, while on the opposite side it is rectangular. As a result, the support is ideal for securing set up room and recovery room. It can also be successfully used to secure three-way intersections of underground workings. To a large extent, however, the importance of these advantages is diminished by relatively low load-bearing parameters, resulting from a partially straight canopy, as well as the asymmetrical distribution of the load acting on the support in underground conditions. In order to ensure the proper and optimal operation of such frames, in addition to the standard requirements for roof supports, additional conditions must be met. The basic requirement is to support the end of the canopy on the corner of the excavation. This article presents examples of arch-rectangular supports, their applications as well as laboratory tests and strength analysis of the frames and its elements. These tests allowed the requirements regarding the construction of the frame, the selection of the support and the conditions of building in the excavation to be specified.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44327552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/ams.2020.133196
Narges Sadat Tayarani, S. Jamali, Mehdi Motevalli Zadeh
The deformation modulus of the rock mass as a very important parameter in rock mechanic projects generally is determined by the plate load in-situ tests. While this test is very expensive and time-con-suming, so in this study a new method is developed to combin artificial neural networks and numerical modeling for predicting deformation modulus of rock masses. For this aim, firstly, the plate load test was simulated using a Finite Difference numerical model that was verified with actual results of the plate load test in Pirtaghi dam galleries in Iran. Secondly, an artificial neural network is trained with a set of data resulted from numerical simulations to estimate the deformation modulus of the rock mass. The results showed that an ANN with five neurons in the input layer, three hidden layers with 4, 3 and 2 neurons, and one neuron in the output layer had the best accuracy for predicting the deformation modulus of the rock mass.
{"title":"Combination of Artificial Neural Networks and Numerical Modeling for Predicting Deformation Modulus of Rock Masses","authors":"Narges Sadat Tayarani, S. Jamali, Mehdi Motevalli Zadeh","doi":"10.24425/ams.2020.133196","DOIUrl":"https://doi.org/10.24425/ams.2020.133196","url":null,"abstract":"The deformation modulus of the rock mass as a very important parameter in rock mechanic projects generally is determined by the plate load in-situ tests. While this test is very expensive and time-con-suming, so in this study a new method is developed to combin artificial neural networks and numerical modeling for predicting deformation modulus of rock masses. For this aim, firstly, the plate load test was simulated using a Finite Difference numerical model that was verified with actual results of the plate load test in Pirtaghi dam galleries in Iran. Secondly, an artificial neural network is trained with a set of data resulted from numerical simulations to estimate the deformation modulus of the rock mass. The results showed that an ANN with five neurons in the input layer, three hidden layers with 4, 3 and 2 neurons, and one neuron in the output layer had the best accuracy for predicting the deformation modulus of the rock mass.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43399845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In technology of coal fines beneficiation in Poland mainly fines jigging processes are in use. In case of steam coal fines beneficiation it is till 80% of the whole amount of produced assortments, while in case of coking coal fines it is 100%. The necessary condition of not homogenous feed separation which is directed to beneficiation process in pulsating water stream is a sufficient liberation of particles. The stratification of particles in working bed causes that particles of certain size, density and shape gather in individual layers in working bed of jig. The introduction of sufficient amount of additional water determines appropriate liberation of particles group, which generates partition into concentrate and tailings. The paper presents the results of sampling of industrial jig used for the beneficiation of coal fines by three various settings of additional amount of water under sieve which is directed to jigging. These amounts were equal to 35, 50 and 70 [m 3 /h]. Collected samples of separation products were then sieved into narrow particle size fractions and divided into density fractions. In such narrow size-density fractions the coordinates of partition curves were calculated for tailings of hard coal fines, which were subsequently approximated by means of Weibull distribution function. The separation precision measured by separation density, probable error and imperfection were determined on the basis of obtained model separation curves. The evaluation of separation effects was performed for a wide particle size fraction: feed directed to jigging process and narrow particle size fractions. The analysis of separation results in size-density fractions allowed to determine the influence of particle size change on the value of probable error. The results of separation precision in size-density fractions were compared with effects of separation of wide particle fraction, i.e. feed directed to jigging process.
{"title":"The Analysis of Coal Fines Separation Precision Exposed to Changeable Hydrodynamic Parameters of Jig Work","authors":"A. Surowiak","doi":"10.24425/122457","DOIUrl":"https://doi.org/10.24425/122457","url":null,"abstract":"In technology of coal fines beneficiation in Poland mainly fines jigging processes are in use. In case of steam coal fines beneficiation it is till 80% of the whole amount of produced assortments, while in case of coking coal fines it is 100%. The necessary condition of not homogenous feed separation which is directed to beneficiation process in pulsating water stream is a sufficient liberation of particles. The stratification of particles in working bed causes that particles of certain size, density and shape gather in individual layers in working bed of jig. The introduction of sufficient amount of additional water determines appropriate liberation of particles group, which generates partition into concentrate and tailings. The paper presents the results of sampling of industrial jig used for the beneficiation of coal fines by three various settings of additional amount of water under sieve which is directed to jigging. These amounts were equal to 35, 50 and 70 [m 3 /h]. Collected samples of separation products were then sieved into narrow particle size fractions and divided into density fractions. In such narrow size-density fractions the coordinates of partition curves were calculated for tailings of hard coal fines, which were subsequently approximated by means of Weibull distribution function. The separation precision measured by separation density, probable error and imperfection were determined on the basis of obtained model separation curves. The evaluation of separation effects was performed for a wide particle size fraction: feed directed to jigging process and narrow particle size fractions. The analysis of separation results in size-density fractions allowed to determine the influence of particle size change on the value of probable error. The results of separation precision in size-density fractions were compared with effects of separation of wide particle fraction, i.e. feed directed to jigging process.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43430245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jacob Miller, Jay Schafler, P. Mulligan, R. Eades, K. Perry, C. Johnson
Explosions of coal dust are a major safety concern within the coal mining industry. The explosion and subsequent fires caused by coal dust can result in significant property damage, loss of life in underground coal mines and damage to coal processing facilities. The United States Bureau of Mines conducted research on coal dust explosions until 1996 when it was dissolved. In the following years, the American Society for Testing and Materials (ASTM) developed a test standard, ASTM E1226, to provide a standard test method characterizing the “explosibility” of particulate solids of combustible materials suspended in air. The research presented herein investigates the explosive characteristic of Pulverized Pittsburgh Coal dust using the ASTM E1226-12 test standard. The explosibility characteristics include: maximum explosion pressure, (Pmax); maximum rate of pressure rise, (dP/dt)max; and explosibility index, (Kst). Nine Pulverized Pittsburgh Coal dust concentrations, ranging from 30 to 1,500 g/m3, were tested in a 20-Liter Siwek Sphere. The newly recorded dust explosibility characteristics are then compared to explosibility characteristics published by the Bureau of Mines in their 20 liter vessel and procedure predating ASTM E1126-12. The information presented in this paper will allow for structures and devices to be built to protect people from the effects of coal dust explosions.
{"title":"Explosive Dust Test Vessel Comparison using Pulverized Pittsburgh Coal","authors":"Jacob Miller, Jay Schafler, P. Mulligan, R. Eades, K. Perry, C. Johnson","doi":"10.24425/123693","DOIUrl":"https://doi.org/10.24425/123693","url":null,"abstract":"Explosions of coal dust are a major safety concern within the coal mining industry. The explosion and subsequent fires caused by coal dust can result in significant property damage, loss of life in underground coal mines and damage to coal processing facilities. The United States Bureau of Mines conducted research on coal dust explosions until 1996 when it was dissolved. In the following years, the American Society for Testing and Materials (ASTM) developed a test standard, ASTM E1226, to provide a standard test method characterizing the “explosibility” of particulate solids of combustible materials suspended in air. The research presented herein investigates the explosive characteristic of Pulverized Pittsburgh Coal dust using the ASTM E1226-12 test standard. The explosibility characteristics include: maximum explosion pressure, (Pmax); maximum rate of pressure rise, (dP/dt)max; and explosibility index, (Kst). Nine Pulverized Pittsburgh Coal dust concentrations, ranging from 30 to 1,500 g/m3, were tested in a 20-Liter Siwek Sphere. The newly recorded dust explosibility characteristics are then compared to explosibility characteristics published by the Bureau of Mines in their 20 liter vessel and procedure predating ASTM E1126-12. The information presented in this paper will allow for structures and devices to be built to protect people from the effects of coal dust explosions.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46788869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/ams.2020.134136
J. Krawczyk
The safety of mining operations in hard coal mines must be constantly developed and improved. There is ongoing multi-directional research focused at best recognition of the phenomenon associated with the properties of the coal-gas system and its connections with mining and geological conditions. This article presents the results of sorption experiments on coals from the Upper Silesian Coal Basin, which are characterized by varying degrees of coalification. One of the parameters that describes the kinetics of methane sorption, determining and providing valuable information about gas hazard and in particular the risk of gas and rock outbursts, is the effective diffusion coefficient De. It is derived from the solution of Fick’s second law using many simplifying assumptions. Among them is the assumption that the carbon matrix consists of only one type of pore – micropores. In fact, there are quite often at least two different mechanisms, which are connected to each other, related to the diffusion of methane from the microporous matrix and flows occurring in voids and macropores. This article presents both the unipore and bidisperse models and a set of comparisons which fit them to experimental curves for selected coals. For some samples the more complex bidisperse model gave much better results than the classic unipore one. The supremacy of the bidisperse model could be associated with the differences in the coal structure related to the coalification degree. Initial results justify further analyses on a wider set of coals using the methodology developed in this paper.
{"title":"The Unipore and Bidisperse Diffusion Models for Methane in Hard Coal Solid Structures Related to the Conditions in the Upper Silesian Coal Basin","authors":"J. Krawczyk","doi":"10.24425/ams.2020.134136","DOIUrl":"https://doi.org/10.24425/ams.2020.134136","url":null,"abstract":"The safety of mining operations in hard coal mines must be constantly developed and improved. There is ongoing multi-directional research focused at best recognition of the phenomenon associated with the properties of the coal-gas system and its connections with mining and geological conditions. This article presents the results of sorption experiments on coals from the Upper Silesian Coal Basin, which are characterized by varying degrees of coalification. One of the parameters that describes the kinetics of methane sorption, determining and providing valuable information about gas hazard and in particular the risk of gas and rock outbursts, is the effective diffusion coefficient De. It is derived from the solution of Fick’s second law using many simplifying assumptions. Among them is the assumption that the carbon matrix consists of only one type of pore – micropores. In fact, there are quite often at least two different mechanisms, which are connected to each other, related to the diffusion of methane from the microporous matrix and flows occurring in voids and macropores. This article presents both the unipore and bidisperse models and a set of comparisons which fit them to experimental curves for selected coals. For some samples the more complex bidisperse model gave much better results than the classic unipore one. The supremacy of the bidisperse model could be associated with the differences in the coal structure related to the coalification degree. Initial results justify further analyses on a wider set of coals using the methodology developed in this paper.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45284421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/ams.2021.136694
A. Kowalski, T. Rutkowski
The impact of caulking of goafs after mining exploitation of a hard coal seam with caving is expressed as the change in value of a a exploitation coefficient which, as defined, is the quotient of the maximum reduction in the surface height of a complete or incomplete trough to the thickness of the exploited seam. The basis for determining the value of the exploitation coefficient was geological and mining data combined with the results of the measurement of subsidence on the surface – measuring line 1222-1301 – of the ruda mine. There, mining was carried out between 2005 and 2019, with a transverse longwall system and the caulking of goafs. The research team used two methods to determine the impact of the caulking applied in the goafs on the value of the exploitation coefficient. in the first method the goafs are filled evenly along the whole longwall, and in the second method unevenly and on a quarterly basis. The determination of the values of the exploitation coefficients for selected measuring points was preceded by the determination of the parameters of the knothe-Budryk theory, which was further developed by J. Białek. The obtained dependencies are linear and the values of the correlation coefficients fall between –0.684 and –0.702, which should be considered satisfactory in terms of experimental data. it is possible to reduce the value of the exploitation coefficient by caulking the goafs by about 18%, when filling the goafs to 0.26% of the height of the active longwall.
{"title":"Caulking of Goafs Formed by Cave-in Mining and its Impact on Surface Subsidence in Hard Coal Mines","authors":"A. Kowalski, T. Rutkowski","doi":"10.24425/ams.2021.136694","DOIUrl":"https://doi.org/10.24425/ams.2021.136694","url":null,"abstract":"The impact of caulking of goafs after mining exploitation of a hard coal seam with caving is expressed as the change in value of a a exploitation coefficient which, as defined, is the quotient of the maximum reduction in the surface height of a complete or incomplete trough to the thickness of the exploited seam. The basis for determining the value of the exploitation coefficient was geological and mining data combined with the results of the measurement of subsidence on the surface – measuring line 1222-1301 – of the ruda mine. There, mining was carried out between 2005 and 2019, with a transverse longwall system and the caulking of goafs. The research team used two methods to determine the impact of the caulking applied in the goafs on the value of the exploitation coefficient. in the first method the goafs are filled evenly along the whole longwall, and in the second method unevenly and on a quarterly basis. The determination of the values of the exploitation coefficients for selected measuring points was preceded by the determination of the parameters of the knothe-Budryk theory, which was further developed by J. Białek. The obtained dependencies are linear and the values of the correlation coefficients fall between –0.684 and –0.702, which should be considered satisfactory in terms of experimental data. it is possible to reduce the value of the exploitation coefficient by caulking the goafs by about 18%, when filling the goafs to 0.26% of the height of the active longwall.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45306889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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