Change Properties of Water Conductivity Height in Coal Roof Induced by Mining in Extra Thick Coal Seams under Influence of Complex Fissures Zone

2012 ◽  
Vol 446-449 ◽  
pp. 59-63
Author(s):  
Shi Guo Sun ◽  
Guo Hong Li ◽  
Jing Xin Wang ◽  
Hong Ying Zhao ◽  
Shao Jie Feng
Keyword(s):  
Underground Mining ◽  
Water Inrush ◽  
Technical Problem ◽  
Mining Area ◽  
Water Conductivity ◽  
Deformation And Failure ◽  
Mining Areas ◽  
Mining Safety ◽  
Strata Deformation ◽  
Overlying Strata

It’s a technical problem of underground mining safety to determine the water conductivity height in coal roof induced by mining under the condition of fully mechanized caving. With a number of mining engineering cases, we studied complex fault zone overlying rock mass damage characteristics under the compound effect of many mining area. The results show that overlying strata deformation and failure is the results of accumulation in mining of each mining area. Therefore, whether the overlying strata water inrush in mining process will happen or not, needs to take account of water in overlying strata in old mining area. Based on the change characteristics of water conductivity height induced by mining in seven mining areas, we built regression forecasting model, and achieved the prediction of water conductivity height induced by mining in lower coal seam, so as to provide a basis for decision-making for the safety of follow-up exploration.

scholarly journals Research on the Evolution Characteristics of Rock Mass Response from Open-Pit to Underground Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiabo Geng ◽  
Qihang Li ◽  
Xiaoshuang Li ◽  
Tao Zhou ◽  
Zhifang Liu ◽  
...  
Keyword(s):  
Underground Mining ◽  
Vertical Direction ◽  
Mining Area ◽  
Open Pit ◽  
Measuring Point ◽  
Deformation And Failure ◽  
Ore Body ◽  
Evolution Characteristics ◽  
The Impact ◽  
Overlying Strata

This study is based on the engineering background of pit no. 2 in Jinning Phosphate Mine, China. In order to systematically analyze the movement, deformation, and failure laws of surrounding rocks in underground stopes. The room and pillar method is used to excavate and stop the ore bodies in the mining area. Combined with the similar physical model experiments and discrete element MatDEM numerical simulations, it reveals the deformation and failure laws and evolution characteristics of the surrounding rock of the stope in the process of converting from open-pit to underground mining. The results show the following: (1) Along the inclination of the ore body, the farther the horizontal and vertical displacements are from the underground stope, the less the impact of mining stress. On the other hand, along the inclined vertical direction of the ore body, the farther the measuring point is from the stope, the smaller the range of mining influence will be. (2) In the process of ore body recovery, the rupture of the overlying strata of the stope has an obvious layered structure, with collapse zones, fissure penetrating zones, and microfracture loosen zones appearing from the bottom to top. In addition, the movement and destruction of the overlying strata of the entire stope is an “elliptical arch.” Therefore, the results of similar simulation experiments and numerical simulation are basically consistent.

scholarly journals A Mechanical Model of the Overlying Rock Masses in Undersea Coal Mining and a Stress-Seepage Coupling Numerical Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jie Fang ◽  
Lei Tian ◽  
Yanyan Cai ◽  
Zhiguo Cao ◽  
Jinhao Wen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mining ◽  
Water Inrush ◽  
Mining Area ◽  
Analysis Model ◽  
Fractured Zones ◽  
Working Face ◽  
Seam Mining ◽  
Overlying Strata

The water inrush of a working face is the main hidden danger to the safe mining of underwater coal seams. It is known that the development of water-flowing fractured zones in overlying strata is the basic path which causes water inrushes in working faces. In the engineering background of the underwater mining in the Longkou Mining Area, the analysis model and judgment method of crack propagation were created on the basis of the Mohr–Coulomb criterion. Fish language was used to couple the extension model into the FLAC3d software, in order to simulate the mining process of the underwater coal seam, as well as to analyze the initiation evolutionary characteristics and seepage laws of the fractured zones in the overlying strata during the advancing processes of the working face. The results showed that, during the coal seam mining process, the mining fractured zones which had been caused by the compression-shear and tension-shear were mainly concentrated in the overlying strata of the working face. Also, the open-off cut and mining working face were the key sections of the water inrush in the rock mass. The condition of the water disaster was the formation of a water inrush channel. The possible water inrush channels in underwater coal mining are mainly composed of water-flowing fractured zones which are formed during the excavation processes. The numerical simulation results were validated through the practical engineering of field observations on the height of water-flowing fractured zone, which displayed a favorable adaptability.

Water-Inrush Mechanism while Fault Zone Secondary Activated in Mining

2012 ◽  
Vol 524-527 ◽  
pp. 799-802
Author(s):  
Shi Guo Sun ◽  
Shao Jie Feng ◽  
Jia Hao Lei
Keyword(s):  
Fault Zone ◽  
Fracture Zone ◽  
Rock Fracture ◽  
Water Inrush ◽  
Mining Area ◽  
Water Conductivity ◽  
Sublevel Caving ◽  
Discontinuous Deformation ◽  
Height Increase ◽  
The Impact

As many different size faults in the fully-mechanized sublevel caving mining area overlying rock, undermine the continuity of rock deformation, and the occurrence of different conditions, the impact properties vary widely. This paper studies the impact of faults on the water inrush with specific examples of project, obtained the discontinuous deformation on both sides of fault zone induce the fault zone secondary activate and result in it’s water transmitting ability dramatic increase; with the mining geometry increases, the water flowing-fracture zone height increase and lead to the water conductivity channel of faults connect with rock fracture zone, so as to constitute water inrush channel and likely to cause water inrush accident, so to explore the influence of fault for underground work safety has important theoretical significance and application value.

scholarly journals Study on the mechanism of water inrush in the arid western mining area

2019 ◽  
Vol 118 ◽  
pp. 03008
Author(s):  
Chao Zheng ◽  
Lan Yu ◽  
Jiangyi He ◽  
Fengfeng Yang ◽  
Jufeng Zhang
Keyword(s):  
Large Scale ◽  
Water Pressure ◽  
Water Inrush ◽  
Hydrodynamic Pressure ◽  
Mining Area ◽  
Mining Areas ◽  
Isolation Layer ◽  
Working Face ◽  
Combined Action ◽  
Tension Fracture

The analysis found that the coal mining process in the western mining area has the mining loss and disaster effect of the water-rich aquifer of the coal seam roof, which is mainly manifested by the overburden water in the roof. On this basis, the formation and development of the separation water of the roof is proposed, and the mechanism of the water inrush from the layer is revealed. It is found that there is hydrostatic pressure and hydrodynamic pressure in the separated water, under the combined action of bed separation water pressure, the mining-induced fracture and water-isolation layer tension fracture are connected, which causes water inrushing in the coal working face of the mine, and provides a theoretical guarantee for the large-scale development of coal resources in western mining areas.

Tracking the Land Use/Land Cover Change in an Area with Underground Mining and Reforestation via Continuous Landsat Classification

2019 ◽  
Vol 11 (14) ◽  
pp. 1719 ◽  
Author(s):  
Jiaxin Mi ◽  
Yongjun Yang ◽  
Shaoliang Zhang ◽  
Shi An ◽  
Huping Hou ◽  
...  
Keyword(s):  
Land Use ◽  
Random Forest ◽  
Land Cover ◽  
Large Scale ◽  
Underground Mining ◽  
Mining Area ◽  
Random Forest Classifier ◽  
Land Use Land Cover ◽  
Lulc Change ◽  
Mining Areas

Understanding the changes in a land use/land cover (LULC) is important for environmental assessment and land management. However, tracking the dynamic of LULC has proved difficult, especially in large-scale underground mining areas with extensive LULC heterogeneity and a history of multiple disturbances. Additional research related to the methods in this field is still needed. In this study, we tracked the LULC change in the Nanjiao mining area, Shanxi Province, China between 1987 and 2017 via random forest classifier and continuous Landsat imagery, where years of underground mining and reforestation projects have occurred. We applied a Savitzky–Golay filter and a normalized difference vegetation index (NDVI)-based approach to detect the temporal and spatial change, respectively. The accuracy assessment shows that the random forest classifier has a good performance in this heterogeneous area, with an accuracy ranging from 81.92% to 86.6%, which is also higher than that via support vector machine (SVM), neural network (NN), and maximum likelihood (ML) algorithm. LULC classification results reveal that cultivated forest in the mining area increased significantly after 2004, while the spatial extent of natural forest, buildings, and farmland decreased significantly after 2007. The areas where vegetation was significantly reduced were mainly because of the transformation from natural forest and shrubs into grasslands and bare lands, respectively, whereas the areas with an obvious increase in NDVI were mainly because of the conversion from grasslands and buildings into cultivated forest, especially when villages were abandoned after mining subsidence. A partial correlation analysis demonstrated that the extent of LULC change was significantly related to coal production and reforestation, which indicated the effects of underground mining and reforestation projects on LULC changes. This study suggests that continuous Landsat classification via random forest classifier could be effective in monitoring the long-term dynamics of LULC changes, and provide crucial information and data for the understanding of the driving forces of LULC change, environmental impact assessment, and ecological protection planning in large-scale mining areas.

scholarly journals Three-Dimensional Physical Similarity Simulation of the Deformation and Failure of a Gas Extraction Surface Well in a Mining Area

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Junhui Fu ◽  
Haitao Sun ◽  
Guangcai Wen ◽  
Rifu Li
Keyword(s):  
Shear Deformation ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Mining Area ◽  
Gas Extraction ◽  
Horizontal Shear ◽  
Deformation And Failure ◽  
Key Strata ◽  
Mining Areas ◽  
Rock Movement

Surface well deformation and failure in a mining area are a key issue challenging the surface well gas extraction technique. To provide information for the design of gas extraction surface wells in mining areas, the deformation and failure of surface wells with different materials under the influence of mining-induced rock movement were analyzed based on a three-dimensional physical similarity simulation and key strata theory. The research findings reveal that the fractures in the overlying strata had an elliptic-parabolic shape. The stope center was the highest point in the fracture zone. Horizontal shear deformation was most likely to occur in the thick strata (horizontal shear deformation could be larger if they were key strata) with large strength and stiffness near the intersection between the fracture surface of the overlying strata and the surface well. Due to the shear force and bending moment of the key strata, the surface well deformed into an S-shape. In addition, the surface well was vulnerable to shear deformation in the key strata. The surface well deformation did not weaken from bottom to top due to rock movement. Instead, it was subject to the influence of the rupture strength of the key strata. The surface well above the key strata was prone to tensile strain-compressive strain transition. In contrast, an abrupt change in the compressive strain occurred in the surface well below the key strata where tensile failure may occur. Moreover, a mechanical model of the surface well during the movement of the key strata was established according to the characteristics of the surface well deformation. The test results provide important information on the design optimization of surface wells and high-risk area protection in mining areas.

scholarly journals Slope ranking and geohazards correlation analysis for combined open-underground mining area

2018 ◽  
Author(s):  
Zhang Jin
Keyword(s):  
Correlation Analysis ◽  
Water Conservation ◽  
Laser Scanning ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Ground Subsidence ◽  
Data Sets ◽  
Mining Areas ◽  
Factor Data

Geohazards in mining areas are mainly ground subsidence, slope landslides and ground cracks, surface cover degradation and environmental ecological pattern destruction. The classification and rank of terrain slope and the feature area extraction of the slope are the important content for the correlation analysis with the geohazards. The slope classification and rank index system for soil and water conservation, land use and man-made ground disasters was analyzed. According to the characteristics of open pit and underground associated mining area, we comprehensively analyzed the spatial correlation between different ground disaster and terrain features and landform types, and propose a new slope ranking index, dividing slope zones and forming slope classification map. Especially slope area of 35-45 degrees and more than 45 degrees was extracted, and the relationship between regional geohazards and slope zone was analyzed. The application of terrestrial laser scanning technology to establish open-pit high precision digital elevation model, extraction of slope, slope type, gully density characteristic factor, topography factor data sets are established, and correlation analysis, to enhance disaster information content.

scholarly journals InSAR monitoring surface deformation induced by underground mining using Sentinel-1 images

2020 ◽  
Vol 382 ◽  
pp. 237-240
Author(s):  
Ling Zhang ◽  
Daqing Ge ◽  
Xiaofang Guo ◽  
Bin Liu ◽  
Man Li ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Surface Deformation ◽  
Underground Mining ◽  
Deformation Gradient ◽  
Mining Area ◽  
Interferometric Synthetic Aperture Radar ◽  
Mining Areas ◽  
Temporal Decorrelation ◽  
Land Deformation ◽  
Small Baseline

Abstract. Land subsidence can be caused by underground mining activities. Interferometric Synthetic Aperture Radar (InSAR) has became an economic, effective and accurate technique for land deformation survey and monitoring. In mining areas, there may be several factors to overcome for the succsessful application of InSAR, such as temporal decorrelation and detectable deformation gradient, that limit the ability of InSAR to monitoring rapid land subsidence. In this paper, images obtained by the Sentinel-1 satellite with 6 or 12 d revisiting time are used to improve the ability to detect a deformation gradient, and reduce the influence of temporal decorrelation. By combining Small Baseline Subsets (SBAS) and Interferometric Point Target Analysis (IPTA) methods, using the Nanhu mining area in Tangshan as an example, the spatial continuous results of land subsidence in this mining area are obtained with a 70 cm per year maximum rate, which clearly characterizes the deformation field and its deformation process. The results show that InSAR is a useful way to monitor land subsidence in a mining area and provides further data for environment mine restoration.

scholarly journals WSN Localization Algorithm on Underground Mining Area

2021 ◽  
Vol 23 (06) ◽  
pp. 464-475
Author(s):  
Shailendra Kumar Rawat ◽  
◽  
Dr. Prof. S. K. Singh ◽  
Dr. Ajay Kumar Bharti ◽  
◽  
...  
Keyword(s):  
Network Formation ◽  
Underground Mining ◽  
Research Work ◽  
Mining Area ◽  
Localization Algorithm ◽  
Mining Areas ◽  
Localization Scheme ◽  
Recent Developments ◽  
The Difference ◽  
Outdoor Localization

The main aim or goal of our research work is to localize the workers working in the mining area exactly or with minimum localization error. Network formation in mining areas is always very crucial. Laborers working in mining areas need strong availability of network as when they go down or deep in a mining area they can be rescued easily. It can only be possible when we know the exact location of the worker working in the particular area. For this, we need a better localization scheme. Many recent developments have been made in the field of the mining area. Random forest scheme, SVM-based regressive localization, Wi-Fi-based localization, and these are some schemes developed so far. RSSI and Trilateration work for both indoor and outdoor localization. The difference is only in terms of temperature because indoor temperature is different from outdoor temperature. When we are working on the basis of distance and signal strength then the proposed localization algorithm is suitable for hill areas too. From the results of the simulation, the new localization algorithm proposed in the paper with error checking and correction increases the accuracy of the localization in the X direction is 99.98 and in Y direction is 99.97 algorithms based on RSSI and dual prediction.

scholarly journals Comparative study on Hydrogeological conditions of Huaihe mining area

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Xiaolin Cheng ◽  
Meichen Yu ◽  
Jiayun Zhang
Keyword(s):  
Pore Water ◽  
Quaternary System ◽  
Water Inrush ◽  
Fine Sand ◽  
Mining Area ◽  
Coal Production ◽  
Water Group ◽  
Mining Areas ◽  
Hydrogeological Conditions ◽  
Similarities And Differences

Lianghuai Mining Area is one of the 13 large coal bases in China. It is an important coal and coal production base in China. Mine water inrush accidents occur frequently, resulting in economic and human resource losses, reflecting the importance of the study of hydrogeology in mining areas. In this paper, the hydrogeological conditions of Bozhou and Huainan Panxie mine are analyzed, and the similarities and differences between the hydrogeological conditions of the two mines are summarized. The shallow pore water group in the Bozhou area is composed of the Quaternary system of the Quaternary system (Q4d) and the upper part of the upper part of the Mao Tong group (Q3m). The lithology of the aquifer is silt, silt and fine sand. The shallow pore water group of the Panxian Pancho Formation in Huainan is composed of the Upper Pleistocene of the Quaternary system and the Holocene strata. The lithology is mainly composed of fine sand. The main sources of shallow pore water supply in the two areas are precipitation infiltration, mainly for evaporation, lateral runoff, artificial mining and deep flow and discharge to the river.

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