scholarly journals Research on determining the safe mining depth in special geological conditions of Mong Duong coal mine

2021 ◽  
Vol 62 (5) ◽  
pp. 76-83
Author(s):  
Chung Van Pham ◽  
Dac Manh Phung ◽  
Ha Thu Thi Le ◽  
Trong Gia Nguyen ◽  
Trung Thanh Ngo ◽  
...  
Keyword(s):  
Coal Mine ◽  
Underground Mining ◽  
Water Bodies ◽  
Coal Seams ◽  
Mining Depth ◽  
Geological Conditions ◽  
Mineral Loss ◽  
Safe Mining

The displacement and deformation of strata due to underground mining is one of the factors that negatively affect the safety of production activities. The strata displacement and deformation depend on many factors such as mining geological conditions, safe mining depths, and mining technologies. The determination of the safe depths is important for calculating the size of safety pillars to minimize mineral loss. To date, there have been many studies to determine safe mining depths under normal geological conditions. However, not much research has been conducted to determine safe mining depths with special geological conditions such as many folds, breaks, faults, and under water-bearing objects. This research introduces a method to determine the safe mining depths for the reservoir set in special geological conditions with folds and excavating several seams under water bodies. The proposed method employs the principle of the similar geological zone theory to calculate the safe mining depths. The method is applied to the Mong Duong coal mine, with three coal seams numbered 5, 6, and 7 with the depth of 210, 180, and 136 m, respectively. The results of mining depths safe obtained H5= 240m, H6 =192m, H7= 136m, respectively.

scholarly journals Substantiation of Safe Conditions During Undermining of Hydraulic Waste Disposal

2018 ◽  
Vol 41 ◽  
pp. 01007
Author(s):  
Yuriy Kutepov ◽  
Aleksandr Mironov ◽  
Maksim Sablin ◽  
Elena Borger
Keyword(s):  
Rock Mass ◽  
Waste Disposal ◽  
Coal Mine ◽  
Water Body ◽  
Water Inflow ◽  
Open Pit ◽  
Coal Seams ◽  
Geological Conditions ◽  
Mine Workings ◽  
Mine Dump

This article considers mining and geological conditions of the site “Blagodatny” of the mine named after A.D. Ruban located underneaththe old open pit coal mine and the hydraulic-mine dump. The potentially dangerous zones in the undermined rock mass have been identified based onthe conditions of formation of water inflow into mine workings. Safe depthof coal seams mining has been calculated depending on the type of water body – the hydraulic-mine dump.

scholarly journals Reference P-wave velocity in coal seams at great depths in Jastrzebie coal mine

2019 ◽  
Vol 133 ◽  
pp. 01011
Author(s):  
Jakub Kokowski ◽  
Zbigniew Szreder ◽  
Elżbieta Pilecka
Keyword(s):  
Wave Velocity ◽  
Coal Mine ◽  
Velocity Model ◽  
P Wave ◽  
Coal Seams ◽  
Data Set ◽  
Seismic Profiling ◽  
Reference Velocity ◽  
P Wave Velocity ◽  
Geological Conditions

In the study, the determining of the reference velocity of the P-wave in coal seams used in seismic profiling to assess increases and decreases in relative stresses at large depths has been presented. The seismic profiling method proposed by Dubinski in 1989 covers a range of depth up to 970 m. At present, coal seams exploitation in Polish coal mines is conducted at greater depths, even exceeding 1200 m, which creates the necessity for a new reference velocity model. The study presents an empirical mathematical model of the change of the P-wave velocity in coal seams in the geological conditions of the Jastrzebie coal mine. A power model analogous to the Dubinski’s one was elaborated with new constants. The calculations included the results from 35 measurements of seismic profiling carried out in various coal seams of the Jastrzebie mine at depths from 640 to 1200 m. The results obtained cause changes in the result of calculations of seismic anomalies. Future validation of the proposed model with larger data set will be required.

Research on Similar Materials Simulation Test for Protective Coal-Seams of Group B Coal-Seams of Panyi Coal Mine of China

2012 ◽  
Vol 204-208 ◽  
pp. 1389-1394 ◽  
Author(s):  
Feng Cai ◽  
Ze Gong Liu
Keyword(s):  
Coal Mine ◽  
Coal Field ◽  
Coal Seams ◽  
Simulation Test ◽  
Mining Depth ◽  
Changing Trends ◽  
Longwall Panel ◽  
Materials Simulation ◽  
Similar Materials ◽  
Group B

Protective technology is one of most effective technologies for regional gas control technology. Huainan Coal Field is a typical coal field with deep and low permeability multi coal-seams, and it is one of most serious coal field in gas disasters. Currently, Huainan Coal Field has completely entered the stage of extracting Group B coal-seams (average mining depth is about 650m). In order to research and obtain the results of stress relief of adjacent coal-seams after extracted protective coal-seam, taking advantage of the method of similar materials simulation test and taking 11415 longwall panel of Group B coal-seams of Panyi Coal Mine of Huainan Coal Field, the changing trends of abutment pressure, displacement as well as permeability of adjacent coal-seams are systematically studied. The researching results can provide safeguard for high-effective gas drainage, eliminate the risk of coal and gas outburst as well as high effective production.

scholarly journals Determination of the Ultimate Underground Mining Depth considering the Effect of Granular Rock and the Range of Surface Caving

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Rongxing He ◽  
Jing Zhang ◽  
Yang Liu ◽  
Delin Song ◽  
Fengyu Ren
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Mechanical Model ◽  
Surface Deformation ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Depth

Continuous mining of metal deposits leads the overlying strata to move, deform, and collapse, which is particularly obvious when open-pit mining and underground mining are adjacent. Once the mining depth of the adjacent open-pit lags severely behind the underground, the ultimate underground mining depth needs to be studied before the surface deformation extends to the open-pit mining area. The numerical simulation and the mechanical model are applied to research the ultimate underground mining depth of the southeast mining area in the Gongchangling Iron mine. In the numerical simulation, the effect of granular rock is considered and the granular rock in the collapse pit is simplified as the degraded rock mass. The ultimate underground mining depth can be obtained by the values of the indicators of surface movement and deformation. In the mechanical model, the modified mechanical model for the progressive hanging wall caving is established based on Hoke’s conclusion, which considers the lateral pressure of the granular rock. Using the limiting equilibrium analysis, the relationship of the ultimate underground mining depth and the range of surface caving can be derived. The results show that the ultimate underground mining depth obtained by the numerical simulation is greater than the theoretical calculation of the modified mechanical model. The reason for this difference may be related to the assumption of the granular rock in the numerical simulation, which increases the resistance of granular rock to the deformation of rock mass. Therefore, the ultimate underground mining depth obtained by the theoretical calculation is suggested. Meanwhile, the surface displacement monitoring is implemented to verify the reasonability of the ultimate underground mining depth. Monitoring results show that the indicators of surface deformation are below the critical value of dangerous movement when the underground is mined to the ultimate mining depth. The practice proves that the determination of the ultimate underground mining depth in this work can ensure the safety of the open-pit and underground synergetic mining.

Analysis of the Relative Position of the Slope and Underground Mining Area and its Influence Properties

2013 ◽  
Vol 634-638 ◽  
pp. 3277-3281 ◽  
Author(s):  
Shi Guo Sun ◽  
Hong Yang ◽  
Chun Sheng Li ◽  
Bao Lin Zhang ◽  
Jia Wang ◽  
...  
Keyword(s):  
Slope Stability ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Stability Factor ◽  
Mining Depth ◽  
Extracellular Region ◽  
Geological Conditions ◽  
Slope Rock ◽  
The Stability

The stability state of slope rock mass is relating to each other’s relative location during the transformation from open-pit to underground mining, it’s the most disadvantageous influence on the slope stability when the underground mining area is located in the toe of slope, and it’s the best influence as in the slope extracellular region. Slope stability factor changes with the geometric dimensions of underground mining increased, but not in direct proportion. Under the condition of constant geometric dimensions of mining area, the influence on slope stability is changing with the mining depth increased. Thus indicating that the influence on slope stability by underground mining has its spatial property, and to determine the specific influence value requires a combination of many factors, such as the relationship of relative spatial position, the geometric dimensions of mining area, engineering geological conditions and so on.

INFLUENCE OF ANALYSIS RESULTS OF ANALYTICAL COAL SAMPLES ON THE PREDICTION ACCURACY OF HAZARDOUS PROPERTIES OF COAL SEAMS

2021 ◽  
pp. 176-186
Author(s):  
Yevhen Rudniev ◽  
◽  
Vyacheslav Galchenko ◽  
Elvira Filatieva ◽  
Mykhailo Filatiev ◽  
...  
Keyword(s):  
Coal Mine ◽  
Calorific Value ◽  
Mining Area ◽  
The State ◽  
Coal Seams ◽  
Initial State ◽  
Mining Operations ◽  
Mineral Components ◽  
Scientific Substantiation

Purpose: to establish possible quantitative errors in determining the values of some indicators of the degree of metamorphism without attracting the content of total moisture and mineral impurities to predict the hazardous properties of coal mine layers during mining. Methodology: based on the use of initial data on the quality indicators and properties of coals for specific coal seams, given in the reference sources, with the subsequent recalculation of the state of samples from their dry ashless or ashless state to the raw state. Comparison of the samples of indicators were determined, respectively, using analytical samples and based on the results of recalculation to the initial state (close to the production state), conclusions were drawn about possible errors in the case of using the analysis results of the analytical samples to predict hazardous properties of mines. Results: The analytical state of the samples for dry ashless state (daf) or wet ashless state (af) does not correspond to the state of coal in the working area of mining operations (r), which most accurately characterizes the manifestation of mine hazardous properties. The indicators of the release of volatile substances during thermal decomposition of coals, which are used to predict the hazardous properties of mine coal seams, do not directly reflect changes in the elemental composition of coals during metamorphic transformations. Methods for preparing analytical samples provide for grinding to small fractions, removing external moisture and enriching to ash content less than 10%, which does not correspond to the state of coal (r) in the mining area. The use of indicators set for dry ashless combustible (organic) mass excludes the possibility of analyzing the influence of moisture and mineral impurities on the manifestation of the hazardous properties of coal seams. The use of such indicators to predict the hazardous properties of mine coal seams can lead to errors in their determination of 45 ÷ 50%. The hazardous properties of coal seams can be adequately characterized only by the combined composition and properties of organic matter and mineral impurities in a state close to the presence of coal in the mining area. Using the example of possible significant errors in the calorific value, in the case of its use to characterize the hazardous properties of coal mine seams, the expediency of scientific substantiation of a set of indicators for a reliable forecast of a specific hazardous property for a specific seam formation was proved. Scientific novelty: hazardous properties of coal seams are reliably predicted on the basis of the composition and properties of organic and mineral components, reduced to conditions close to the state during mining operations. Practical value: the results obtained give grounds to scientifically substantiate the selection of the necessary indicators for predicting a specific hazardous property of coal seams and make proposals for improving the regulatory framework for the safe conduct of mining operations.

scholarly journals Justification of stripping and development of a modular mine site for a combined coal mining method in Kuzbass on the example Baikaimskaya mine site

2020 ◽  
Vol 243 ◽  
pp. 293
Author(s):  
Roman Shishkov ◽  
Valerii Fedorin
Keyword(s):  
Coal Mining ◽  
Development Strategy ◽  
Coal Mine ◽  
Underground Mining ◽  
Coal Industry ◽  
Open Pit ◽  
Kuznetsk Coal ◽  
Mine Site ◽  
Geological Conditions ◽  
Mining Work

The article considers one actual method for development coal deposits in the Kuzbass by open-underground mining. The scientific and practical advantages of the proposed method due to the use of common infrastructure of coal mine and a modular mine site (subsequently transformed into a mining and technological structure operating according to the mine – longwall scheme) are presented. Currently, a development strategy for Kuzbass until 2035 has been developed. As part of the strategy, a draft program for subsoil use is being formed in the coal industry department. The program should take into account all the positive and negative aspects associated with coal mining in cities and municipal areas and also their prospects. In the Kuznetsk coal basin, 42 mines and 52 opencast mines are mining, of which 12 enterprises use partially unified infrastructure. According to the results of open-underground mining work conducted by the laboratory of the Institute of Coal and Coal Chemistry of the Siberian Branch of the Russian Academy of Sciences (Institute of Coal SB RAS), the list of sites includes favorable mining and geological conditions with incidence angles of up to 18 degrees. As open-pit coal production increases, many sites encounter such a parameter as maximum allowable (boundary) strip ratio. At the stage of preparing the feasibility study for the development of a coal deposit, this coefficient is calculated first of all, since duration of enterprise’s work and its economic component depend on it. In order to increase parameters, it is necessary to carry out transition from open works to underground. As a result, coal mine will not work at a loss, providing production with an economically disadvantageous strip ratio.

scholarly journals DETERMINATION OF THE RATIONAL LENGTH OF THE BLOCK ALONG THE STRIKE FOR EXPANSION TO PROVIDE SAFETY AND EFFICIENCY IN THE WORKING OF THE MEDIUM THICK IN-CLINED COAL SEAMS WITH THE ROOM AND PILLAR SYSTEM IN THE QUANG NINH COAL BASIN

2018 ◽  
pp. 3-8
Author(s):  
Duc Thang Pham ◽  
Victor G. Vitcalov
Keyword(s):  
Coal Seams ◽  
Coal Basin ◽  
Foreign Experience ◽  
Geological Conditions ◽  
Rational Length ◽  
Working Out ◽  
Quang Ninh ◽  
Excavation Area

An analysis of the constraints that apply the technology and the complexities of the mining and geological conditions of the Quang Ninh coal basin. The possi-bility and expediency of using the foreign experience of working out of the me-dium thick inclined coal seams in the mines of Vietnam. The scheme of prepara-tion and working out of the excavation area is given in view of the technological features in difficult mining and geological conditions, using the room and pillar system and determination of the rational length of the block along the strike.

scholarly journals Control of the Internal and External Staggered Distance of Coal Mining Face to the Water-Conducting Fissures in the Overlying Strata of the Near Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhiyuan Jin ◽  
Tao Peng
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Coal Mine ◽  
Calculation Formula ◽  
Coal Seams ◽  
Coal Face ◽  
Geological Conditions ◽  
Mining Face ◽  
Seam Mining ◽  
Water Proof

In Northwest China, rainfall is low, water resources are scarce, and the ecological environment is fragile. For shallow-buried and close-spaced coal seams with a thickness of upper coal bed >60∼70 m, the water-conducting fissures of the overlying rock will not penetrate the water-isolating layer after the upper coal seam is mined; the internal and external gap angles of the water-conducting fissures are not generated from the water-isolating layer. We set out to explore the critical internal and external dislocations for the second significant development of water-conducting fissures in the overlying rock after coal mining under control. A calculation model for the critical internal and external staggered distances of coal mining face in shallow-buried and close-spaced coal seams is established, the calculation formula is given, and the calculation formula for the critical seam mining ratio under the condition of internal staggered mining mode is given. Numerical simulation performed by UDEC methods: taking the overburden strata in the shallow-buried and close-spaced coal seam mining area of Shigetai Coal Mine as a prototype, it was verified that the critical internal and external offsets of the coal mining face in shallow-buried and close-spaced coal seams have a significant effect on the overlying water flow cracks in the mining of the lower coal seam. For the feasibility of developmental control, according to the engineering geological conditions of Shigetai, through the calculation method of external staggered distance, it is concluded that the distance of the open cut of the lower coal face and the upper coal face is only 21∼27 m, which is much smaller than the water barrier. It does not produce the critical distance of the water-conducting cracks. Therefore, in the process of mining the lower coal seam, the water-proof layer will produce water-conducting cracks, lose its water-proof performance, and cause water loss. This is also the cause of the water inrush accident in Shigetai Coal Mine.

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