scholarly journals Control for the large section roadway under small abandoned mines in the same coal seam by secondary support

2020 ◽  
Vol 8 (10) ◽  
pp. 3476-3489
Author(s):  
Yang Tai ◽  
Hongchun Xia ◽  
Hongjie Liu ◽  
Zhanyuan Ma ◽  
Yanqun Zhang
Keyword(s):  
Coal Seam ◽  
Abandoned Mines ◽  
Large Section ◽  
Secondary Support

Techno-Economic Feasibility Analysis of Pumped Storage Hydroelectricity in Abandoned Underground Coal Mines

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Dacheng Shang ◽  
Peng Pei ◽  
Yujun Zuo
Keyword(s):  
Coal Seam ◽  
Capital Investment ◽  
Economic Feasibility ◽  
Abandoned Mines ◽  
Cost Of Energy ◽  
Calculation Results ◽  
Pumped Storage ◽  
Geological Constraints ◽  
The Cost ◽  
Cycle Efficiency

Abstract It is anticipated that utilizing the underground space in abandoned mines to build and operate pumped-storage hydroelectricity (PSH) plants can reduce capital investment and geological constraints. However, there are currently few detailed investigations into techno-economic feasibility except for conceptual studies. In this paper, an underground coal mine in Guizhou, China was used as a reference, and the PSH layout was designed; in addition, the head loss, plant efficiency, and major cost components were investigated. The calculation results show that the capital investment of mine-based PSH was 33–50% less than that of conventional PSH. Sensitivity analysis found a clear influence of coal seam inclination on the performance of the mine-based PSH. Under the assumed conditions, the plant cycle efficiency increased from 62.7% to 71.5% when the coal seam dip varied from 5 deg to 25 deg. Depending on different price scenarios, when the coal seam inclination was steep enough, the cost of energy storage of a mine-based PSH plant was competitive compared with conventional PSH, and the plant could even become profitable. The influence of the dip of coal seam was more pronounced when in the lower range (5–15 deg) than the higher range (15–25 deg).

scholarly journals Occurrence Mechanism of Roof-Fall Accidents in Large-Section Coal Seam Roadways and Related Support Design for Bayangaole Coal Mine, China

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Shitan Gu ◽  
Bangyou Jiang ◽  
Gensheng Wang ◽  
Huabin Dai ◽  
Mingpeng Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Large Scale ◽  
Control Method ◽  
Tensile Failure ◽  
Large Section ◽  
Support Design ◽  
Roof Fall ◽  
Occurrence Mechanism ◽  
Fall Accidents

This study focused on large-scale roof-fall accidents occurred in large-section coal seam roadways of Bayangaole Coal Mine, Inner Mongolia, China, and investigated the occurrence mechanism of roof-fall and the related supporting control method in detail. Firstly, the fracture characteristics of the surrounding rocks on the roadway roof were measured using a stratum detector. The results showed that the roadway roof underwent the most severe failure with a maximum deformation of 3.53 m; the bedding separation and fracture zones were distributed at irregular intervals. Accordingly, the entire stratum was separated into several thin sublayers, significantly reducing the stability of roof. In addition, the roof medium grained sandstone of roadway is water-rich strata, and water aggravates the damage of roof. Next, the mechanism of the occurrence of roof-fall accidents in the roadway was elucidated in detail. The following three reasons are mainly attributed to the occurrence of roof-fall accidents: (i) effects of mining-induced stress and tectonic stress, (ii) existence of equipment cavern on the side of roadway, and (iii) unreasonable support parameters. On that basis, a new supporting design is proposed, including a more reasonable arrangement of anchor cables and bolts, bolts with full-length anchorage which are applicable in cracked and water-rich roadway, high-strength anchor cables, and crisscrossed steel bands. Moreover, high pretightening force was applied. Finally, a field test was performed, and the mining-induced roof displacement and stress on anchor cable (bolt) were monitored in the test section. The maximum roof displacements at the two monitoring sections were 143 mm and 204 mm, respectively, far smaller than the roadway’s allowable deformation. Moreover, the stress on roof anchor cables (bolts) was normal, and no anchorage-dragging and tensile failure phenomena were observed. The monitoring data indicated that the new supporting design was remarkable on the control of large-section coal seam roadway roof deformation.

scholarly journals Stability Analysis and Protection Measures of Large Section Tunnel in Coal Rich Weak Rock Stratum

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guannan Zhou ◽  
Zijiang Zhao ◽  
Zhanping Song ◽  
Hongjian Wang
Keyword(s):  
Coal Seam ◽  
Large Scale ◽  
Economic Benefits ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Weak Rock ◽  
Large Section ◽  
Tunnel Face ◽  
Finite Element Software ◽  
Geological Conditions

Due to poor engineering geological conditions of Liujiazhuang tunnel on Shanghai-Kunming Passenger Dedicated Line, the large deformation of weak rock occurs repeatedly during tunnel construction. In this paper, the large-scale finite element software ABAQUS is used to simulate the construction process of a large-section tunnel in weak surrounding rock. It is found that when tunnel face passes through the coal seam, the displacement and stress simulated by the bench method increase abruptly. The maximum stress reaches up to 18 MPa, and displacement reaches 45 mm, which is about twice when without crossing coal seam. It is technically feasible to use the bench method for tunnel construction, under the condition when large settlements is allowed; additionally, the bench method has better technical and economic benefits than that of the CD method. Through the comparative analysis of onsite monitoring data and numerical simulation results, it can be seen that the tunnel is in a dangerous state when passing through the coal seam and measures such as strengthening support or auxiliary advance support should be taken immediately to control the surrounding rock and to ensure tunnel construction safety.

scholarly journals Position optimisation for a roadway under small coal mines in same coal seam: a case study

2020 ◽  
Vol 17 (5) ◽  
pp. 870-882
Author(s):  
Yang Tai ◽  
Guozhi Lu ◽  
Hongchun Xia ◽  
Wenyang Zhang ◽  
Hongjie Liu ◽  
...  
Keyword(s):  
Numerical Model ◽  
Coal Seam ◽  
Lateral Displacement ◽  
Coal Mines ◽  
Industrial Test ◽  
Vertical Stress ◽  
Experimental Results ◽  
Large Section ◽  
Center Distance

Abstract According to the failure law of the 1070 main roadway, this paper proposes a reasonable position for large section roadways under small coal mines and a design for seven roadway positions. RS2 software was used to establish a numerical model to select a reasonable position for the roadway. The influences of roadway positions on roof separation amount, roof subsidence, lateral displacement on the ribs, vertical stress on ribs and roadway failure areas were revealed. On the basis of influence laws, reasonable positions for the roadway could be determined. In this study, a center distance of 5 m was deemed a reasonable position. Finally, an industrial test was conducted at the original roadway. The experimental results indicate that the deformation of the roadway could be well controlled and the roadway position is reasonable.

Analysis and application of coal-seam seismic waves for detecting abandoned mines

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. M7-M15 ◽  
Author(s):  
Daniel J. Yancey ◽  
Matthias G. Imhof ◽  
John E. Feddock ◽  
Tod Gresham
Keyword(s):  
Coal Seam ◽  
Seismic Reflection ◽  
Seismic Waves ◽  
Underground Mine ◽  
Abandoned Mines ◽  
Abandoned Mine ◽  
Reflection Data ◽  
Seismic Methods ◽  
Mine Voids ◽  
Transmission And Reflection

Two in-seam reflection surveys and one transmission survey were acquired at an abandoned underground mine near Hurley, Virginia, to demonstrate the feasibility of detecting abandoned-mine voids utilizing coal-seam seismic waves. Standard, commonly available tools for seismic reflection processing were used. The mine was detected and located by using trapped coal-seam seismic waves observed in both the transmission and reflection data. Detecting the void, however, was not good enough to replace drilling entirely. We conclude that in-seam seismic methods can be used for detection; but if a potential void is detected, focused drilling should be applied for accurate mapping and to circumvent potentially hazardous areas.

scholarly journals The rise of the mine water level in the area of the former Kohinoor II mine and the influence on the surrounding aquifer systems of abandoned mines in the central part of the North Bohemian Brown Coal Basin

2011 ◽  
Vol 59 (3) ◽  
pp. 135-142
Author(s):  
Milan Mikoláš ◽  
Jiří Varady ◽  
Jaroslav Bažant ◽  
František Žoček
Keyword(s):  
Coal Seam ◽  
Water Level ◽  
Brown Coal ◽  
Mine Water ◽  
Abandoned Mines ◽  
Coal Basin ◽  
The North ◽  
Water Pumping ◽  
Aquifer Systems ◽  
Water Rise

The aim of this article is to evaluate the process of terminating the mine water pumping after the liquidation of the Kohinoor II coal mine, situated in the central part of the North Bohemian Brown Coal Basin (NBB) and the subsequent resumption of pumping from the surface after the mine water rise in the area of the former mine to the desired level. We analyzed previously known data, particularly the amount of mine water pumped from the mine area and the surrounding abandoned mines in the past. Further the evaluation of known surrounding abandoned mines aquifer systems, accumulated in the coal seam (underground accumulation of water) and the evaluation of the effect of increasing the water level in the Kohinoor II mine, focusing on the enlargement of the central mine aquifers and the evaluation of the effects of changes in the way of pumping on the surrounding coal seam and its mining with continued safe brown coal mining at the nearby Bílina mine, that can be ensured for at least another 25 years.

Safety Analysis of Tunnel in Gob of High Steep Thick Coal Seam (II) - 3-D Numerical Simulation for Mechanics of Initial and Secondary Support Structure

2011 ◽  
Vol 71-78 ◽  
pp. 1539-1545
Author(s):  
Wen Bin Lu ◽  
Yi Min Wu ◽  
Jie Chen ◽  
He Lin Fu
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Treatment Plan ◽  
Three Dimensional ◽  
Axial Direction ◽  
Tunnel Structure ◽  
Support Structure ◽  
Thick Coal Seam ◽  
Highway Tunnel ◽  
Secondary Support

Taking Wusongshan Tunnel in Tongling City as an example, three-dimensional numerical simulation of new large span highway tunnel built directly through gob of steep coal seam is carried out to study the response of tunnel structure induced by mining. The results showed that, (1) Though immediately backfilling after extraction can prevent the tunnel structure from impact of mining below the tunnel, it is still necessary to forbid extraction below the tunnel consildering the duration time of the extraciton and backfilling activity. (2) Considering the long-term settlement of gob of steep coal seam, net height of the tunnel should be enlarged 50cm to ensure enough space for operation. (3) The tensile and pressive stress of the support structure in the bottom and roof section of the gob are obviously high than other, so comperihencive measures should be taken to reinforce the structure, especially to increase the tensile strength in axial direction. (4) Fortification intensity can be reduced but the fortification should be enlarged if the continuous reinforcement by steel bar is used at the radial construction joints. Based on these results, treatment plan were developed for Wusongshan Tunnel, which can also be refered for other similar projects.

scholarly journals Roadway Support in Deep “Three-Soft” Coal Seam: A Case Study in Yili Mining Area, China

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wenxin Li ◽  
Jinxiao Liu ◽  
Lianjun Chen ◽  
Zhilu Zhong ◽  
Yongle Liu
Keyword(s):  
Coal Seam ◽  
Large Deformation ◽  
Mechanical Test ◽  
Mining Area ◽  
Surrounding Rock ◽  
Rock Properties ◽  
Support Design ◽  
Soft Coal ◽  
Secondary Support ◽  
Soft Coal Seam

This paper analyzes the large deformation of roadway in three-soft coal seam under the influence of tectonic stress. Taking the auxiliary conveying uphill roadway in Yili No. 1 Coal Mine as the engineering background, the deformation and failure mechanism of the surrounding rock and the supporting technology were studied. First, the characteristics of stress field and the surrounding rock properties of deep mining area were investigated through geostress measurement and rock mechanical test. Then, the roadway deformation and the loose circle of the supporting structure were obtained. Based on the results from measurement and theoretical analysis, we proposed a concept, i.e., “Stress adjustment-Strengthening-Grouting-Secondary support.” A numerical model was established to analyze the stress distribution and the state of plasticity in the surrounding rock. According to the results of the geostress measurement and the numerical simulation, a combined support scheme was proposed, i.e., “Yielding bolt & Shotcreting” as the primary support and “Prestressed grouting anchor cable & U-shaped shed” as the secondary support. Finally, the underground practice showed that the proposed support scheme can effectively control the large deformation and maintain the long-term stability of the roadway in deep and three-soft coal seam. The proposed technology has guiding significance for the support design under similar mining conditions.

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