scholarly journals Cemented Backfilling Mining Technology for Gently Inclined Coal Seams Using a Continuous Mining and Continuous Backfilling Method

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bin Lu ◽  
Yongliang Li ◽  
Shizheng Fang ◽  
Hai Lin ◽  
Ye Zhu
Keyword(s):  
Surface Deformation ◽  
New Technology ◽  
Engineering Application ◽  
Filling Material ◽  
Coal Seams ◽  
Mining Technology ◽  
Coal Resources ◽  
Continuous Mining ◽  
Material Transportation ◽  
Coal Pillars

To improve the efficiency and reduce costs of cemented-fill mining, we propose a continuous mining and continuous backfilling (CMCB) method based on the coal resources at the Yuxing mine in Inner Mongolia, China, and constructed a complete filling material transportation system. The new technology is suitable for cemented-fill mining of gently inclined coal seams. Numerical simulations were performed to investigate the dynamic migration law of surrounding rock stress using CMCB cemented-fill mining technology, and similar simulations were conducted to analyze the movement characteristics of the coal overburden. The results show that the coal pillars and filling body alternately bear and support each other during the CMCB process, which resolves the contradiction between mining and filling, achieves parallel mining and filling operations, and improves mining efficiency. The new mining mode exerts minimal disturbance to the overlying rock and effectively controls surface deformation. The engineering application of this technique is promising and provides theoretical guidance and technical support for safe and efficient mining of the same type of coal resources.

scholarly journals Risk Assessment and Prevention of Surface Subsidence under Buildings by Cemented Paste Filling and Strip Mining Methods: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Sun Qiang ◽  
Zhou Nan ◽  
Song Weijian ◽  
Zhao Xu
Keyword(s):  
Surface Deformation ◽  
Surface Subsidence ◽  
Environmental Benefits ◽  
Strip Mining ◽  
Coal Resources ◽  
Industrial Sites ◽  
Coal Recovery ◽  
Geological Conditions ◽  
Continuous Mining ◽  
Residual Coal

Intensive and continuous mining of coal resources in China implies their gradual exhaustion, especially in the eastern regions. While some mines face closure, others have to extract residual coal resources under buildings, water bodies, and industrial sites. Thus, safe and efficient mining of the residual coal resources requires innovative techniques, which would account for the particular site’s geological conditions. In this study, two schemes of roadway mining with cemented paste backfilling (RMCPB) and strip mining are put forward. After analyzing the type, construction, and protection standard of the buildings, the probability integration method and the prediction model are used to assess the surface subsidence and deformation. The research results show that both schemes can control the surface deformation to a certain extent, but RMCPB combines the advantages of a high coal recovery rate and disposal of gangue waste. According to the surface subsidence predicted and measured data, the RMCPB method can effectively control the surface subsidence, deformation, and buildings’ safety. It also yields significant economic and environmental benefits.

scholarly journals Research on Continuous Miner Mining with Backfilling Technology under High Geostress and Complex Conditions

2020 ◽  
Vol 165 ◽  
pp. 03042
Author(s):  
Du Tao
Keyword(s):  
Field Application ◽  
Burial Depth ◽  
Mining Technology ◽  
Coal Resources ◽  
Continuous Miner ◽  
Working Face ◽  
Geological Conditions ◽  
Deformation Speed ◽  
Continuous Mining ◽  
High Geostress

Aiming at the mining seam with large burial depth, strong geostress, large deformation of the roadway, and fast deformation speed, in order to efficiently recover the coal resources at the working face and effectively protect the surface buildings. Based on analyse of the law of the appearance of the underground roadway pressure in the relevant working face, combined with continuous miner mining technology and equipment technical characteristics, this paper proposes to use a combination of continuous miner mining technology and backfilling technology to mine under high geostress geological conditions. And optimize the mining process parameters according to the field application. The results show that the continuous mining miner with backfilling method can achieve the efficient recovery of coal resources under high geostress and complex conditions.

scholarly journals The Influence of the Backfilling Roadway Driving Sequence on the Rockburst Risk of a Coal Pillar Based on an Energy Density Criterion

2018 ◽  
Vol 10 (8) ◽  
pp. 2609 ◽  
Author(s):  
Yi Xue ◽  
Zhengzheng Cao ◽  
Feng Du ◽  
Lin Zhu
Keyword(s):  
Energy Density ◽  
Dynamic Instability ◽  
Coal Pillar ◽  
Optimal Choice ◽  
Mining Technology ◽  
Pillar Stability ◽  
Rockburst Hazard ◽  
Density Factor ◽  
Coal Pillars ◽  
Energy Density Factor

The rockburst hazard has always been an important issue affecting the safety production of coal mines in China. The unreasonable sequencing of roadway driving can lead to the dynamic instability of coal pillars, which subsequently causes rockburst accidents in roadway backfilling mining engineering and poses a serious threat to the safety of the mines. Roadway backfilling mining technology is an effective approach with which to mine corner residual coal resources under buildings, railways, and rivers. An energy density criterion is established and programmed with FISH language using numerical analysis software for the rockburst risk evaluation of coal pillars. On this basis, a numerical simulation model is established based on four scheme types, namely, the sequential mining, one-roadway interval mining, two-roadway interval mining, and three-roadway interval mining schemes. The influence of the backfilling roadway driving sequence on coal pillar stability is investigated, and the change law of vertical stress and energy density factor of coal pillars in different driving sequences in roadway backfilling mining technology are analyzed. According to the research results, the maximum energy density factor value of 21,172 J/m4 for coal pillars in one-roadway interval mining is the lowest among the different schemes. Therefore, the one-roadway interval mining scheme is the optimal choice in roadway backfilling mining technology. The results can be treated as an important basis for the prevention and treatment of coal pillar instability and rockburst in roadway backfilling mining technology.

scholarly journals Mechanisms behind strong strata behaviour in high longwall mining face-ends under shallow covers

2019 ◽  
Vol 16 (3) ◽  
pp. 559-570 ◽  
Author(s):  
Weibing Zhu ◽  
Xiangrui Qi ◽  
Jinfeng Ju ◽  
Jingmin Xu
Keyword(s):  
Longwall Mining ◽  
Coal Pillar ◽  
Field Measurements ◽  
Main Roof ◽  
Longwall Face ◽  
Effective Control ◽  
Coal Seams ◽  
Roof Collapse ◽  
Coal Pillars ◽  
Roadway Deformation

Abstract Safe and efficient mining of shallow coal seams relies on the understanding and effective control of strata behaviour. Field measurements, theoretical analysis and numerical simulations are presented in this study to investigate the mechanism behind abnormal strata behaviour, such as roof collapse and severe roadway deformation, that occurs in high longwall face-ends under shallow cover. We observed that coal pillars with two sides being mined out become unstable when the cover depth exceeds a certain value. The instability of the coal pillar can alter the fracture line of the overlying strata, triggering a reversed rotation of the ‘curved triangle blocks’ that form after the breakage of the overlying main roof. The revolving blocks apply stress on the roof strata directly above the longwall face-end, resulting in roof collapse. The collapse of both the coal pillars and the roof also leads to the advancement and increase of the overlying abutment pressure, which further causes severe roadway deformation in front of the working face. The strong strata behaviour that occurs in high longwall face-ends with shallow cover is presented in this study and countermeasures are proposed, such as widening or strengthening the coal pillar, or implementing destress blasting. The countermeasures we proposed and the results of our analyses may facilitate the safe mining of shallow coal seams with similar problems in the future, and may improve the safety and efficient working of coal mines.

Case study on pressure-relief mining technology without advance tunneling and coal pillars in longwall mining

2020 ◽  
Vol 97 ◽  
pp. 103236 ◽  
Author(s):  
Yajun Wang ◽  
Manchao He ◽  
Jun Yang ◽  
Qi Wang ◽  
Jianning Liu ◽  
...  
Keyword(s):  
Longwall Mining ◽  
Pressure Relief ◽  
Mining Technology ◽  
Coal Pillars

scholarly journals Failure Mechanism and Control Technology of Thick and Soft Coal Fully Mechanized Caving Roadway under Double Gobs in Close Coal Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-23
Author(s):  
Shengrong Xie ◽  
Xiaoyu Wu ◽  
Dongdong Chen ◽  
Yaohui Sun ◽  
En Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Field Distribution ◽  
Control Technology ◽  
Coal Seams ◽  
Anchor Bolt ◽  
Anchor Cable ◽  
Coal Pillars ◽  
Seam Mining ◽  
And Control

The surrounding rock of the roadway under double gobs in the lower coal seams is partially damaged by the mining of the upper coal seam and the stress superimposition of the stepped coal pillars. What is worse, the upper layer of the roof is collapse gangue in double gobs, which makes the anchor cable unable to anchor the reliable bearing layer, so the anchoring performance is weakened. The actual drawing forces of the anchor bolt and anchor cable are only approximately 50 kN and 80 kN, respectively. The roadway develops cracks and large deformations with increasing difficulty in achieving safe ventilation. In view of the above problems, taking the close coal seam mining in the Zhengwen Coal Mine as the engineering background, a theoretical calculation is used to obtain the loading of the step coal pillars and the slip line field distribution of the floor depth. The numerical simulation monitors the stress superimposition of stepped coal pillars and the distribution of elastoplastic areas to effectively evaluate the layout of mining roadways. The numerical simulation also analyzes the effective prestress field distribution of the broken roof and grouting roof anchor cable. A laboratory test was used to monitor the strength of the grouting test block of the broken coal body. Then, we proposed that grouting anchor cable be used to strengthen the weak surface of the roof and block the roof cracks. From on-site measurement, the roadway was seen to be arranged in the lateral stress stabilization area of the stepped coal pillars, the combined support technology of the grouting anchor cable (bolt) + U type steel + a single prop was adopted, the roadway deformation was small, the gas influx was reduced, and the drawing force of the anchor bolt and the anchor cable was increased to approximately 160 kN and 350 kN, respectively. The overall design and control technology of the roadway can meet the site safety and efficient production requirements.

scholarly journals Research situation and prospect of fully mechanized mining technology in thick coal seams in China

2009 ◽  
Vol 1 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Shi-hao Tu ◽  
Yuan Yong ◽  
Yang Zhen ◽  
Xiao-tao Ma ◽  
Wu Qi
Keyword(s):  
Coal Seams ◽  
Mining Technology ◽  
Research Situation

Research of New Filling and Mining Technology Using Waste Rocks in Steep Coal Seams

2012 ◽  
Vol 204-208 ◽  
pp. 1395-1400
Author(s):  
Chuan Wei Zang ◽  
Chuan Le Ma ◽  
Xue An Zhuang
Keyword(s):  
Coal Mining ◽  
Coal Pillar ◽  
Recovery Ratio ◽  
Mining Method ◽  
Coal Seams ◽  
Coal Recovery ◽  
Waste Rocks ◽  
Filling Method ◽  
Gob Area ◽  
Coal Pillars

During the extraction of steeply inclined coal seams, the coal recovery ratio is low be-cause of the coal pillar loss and the production of waste rock is high due to lots of rock roadways which causes serious environmental pollution. This status is conflicted with the strategy of Clean Coal Mining and Green Coal Mining in China, so it is necessary to develop new coal mining method. In this paper, Downward Stratified Gangue Self-filling Method on the Flexible Shield (DSGSMFS) is put forward first. It means that the coal face is lain horizontally and advances along the dip; the flexible shield is used to separate the gob area; the waste rocks are self-filled downward to the top the shield; the coal is broken by drilling and blasting method under the shield, and the broken coal is transported by the electrical winch and the scraping mucker; the flexible shield moves downward automatically by the weight of itself and waste rocks. Field test shows that the strata displacement is effectively controlled by using DSGSMFS, so some coal pillars are recovered; as a result the problem of large quantity gangue and low coal recovery ratio in steep coal seam is solved. DSGSMFS is proved to be a new hopeful and effective coal green mining method.

scholarly journals Subsidence Control Design Method and Application to Backfill-Strip Mining Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiaojun Zhu ◽  
Feng Zha ◽  
Guangli Guo ◽  
Pengfei Zhang ◽  
Hua Cheng ◽  
...  
Keyword(s):  
Coal Mining ◽  
Influencing Factors ◽  
Recovery Rate ◽  
Design Method ◽  
Control Design ◽  
Resource Recovery ◽  
Design Parameters ◽  
Strip Mining ◽  
Filling Material ◽  
Mining Technology

Intensive and massive coal mining causes a series of geological hazards and environmental problems, especially surface subsidence. At present, two major types of subsidence control technology are applied: backfilling technology and partial mining technology. However, the cost of backfill mining is high and partial mining has a low recovery ratio. Therefore, the backfill-strip mining is used to solve the problems of high cost and shortage of filling materials in coal mines at present. A subsidence control design method of backfill-strip mining was proposed in this paper based on the subsidence control effects and economic benefits. First, the stability of the composite support pillar of the filling body and coal pillars in the backfill-strip mining is analyzed, and the values of the main subsidence influencing factors that include the filling material, the size of the backfilling working face, caving mining face, and residual coal pillar are preliminarily determined. Then, the surface movement and deformation are predicted based on the equivalent superposition probability integral method (PIM). The subsidence influencing factors are optimized and determined by comparing the requirements of the safety fortification index of the antideformation ability of surface buildings, resource recovery rate, and coal mining cost. Finally, the mining scheme design parameters of the backfill-strip mining technology are determined. This method is applied in the subsidence control design of backfill-strip mining in the Ezhuang coal mine. Research results show that backfill-strip mining can ensure the safety of surface buildings, increase the resource recovery rate, and reduce coal mining costs through the reasonable design of this method. This study can provide scientific guidance for subsidence disaster control, prevention, and engineering design in backfill-strip mining.

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