Investigation into Key Strata Movement Impact to Overburden Movement in Cemented Backfill Mining Method

A novel and environmental-friendly backfill mining method known as upward slicing longwall-roadway cemented backfill (USLCB) technology has recently been proposed and successfully applied in mines extracting extra-thick coal seams located under sensitive areas. This paper studies the effects USLCB had on roof movement and failure behavior using the mechanical analysis approach. The application of USLCB in the Gonggeyingzi Mine is taken as a case study with roof movement behavior being monitored over a single mining cycle, as well as over multiple mining cycles of different coal slices. In addition, backfill performance requirements to prevent roof failures where USLCB is implemented are studied. The results show that the deflection curves of the roof at the end of each mining cycle during mining the first and the six slices are symmetrical, but they change from asymmetrical to symmetrical during the mining progresses of the second slice to the fifth slice. The final state of roof movement after the first slice, and through to the fifth slice, displays an obvious “flat bottom” pattern in the middle of the deflection curve. The roof movement during the removal of the top slice is noticeably different from other slices. The results also show that the requirements of the elastic modulus, as well as the strength of the backfill, increase as the number of mined slices increases from 1 to 5, but the requirements drop sharply for mining the top slice.

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The Influences of Key Strata Compound Breakage on the Overlying Strata Movement and Strata Pressure Behavior in Fully Mechanized Caving Mining of Shallow and Extremely Thick Seams: A Case Study

Advances in Civil Engineering ◽

10.1155/2019/5929635 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Junmeng Li ◽

Yanli Huang ◽

Jixiong Zhang ◽

Meng Li ◽

Ming Qiao ◽

...

Keyword(s):

Numerical Simulation ◽

Abutment Pressure ◽

Simulation Software ◽

Strata Movement ◽

Key Strata ◽

Pressure Behavior ◽

Ground Pressure ◽

Working Face ◽

Overlying Strata Movement ◽

Overlying Strata

In order to analyze the impact of compound breakage of key strata on overlying strata movement and strata pressure behavior during the fully mechanized caving mining in shallow and extremely thick seams, this paper took the 1322 fully mechanized caving face in Jindi Coal Mine in Xing County as the engineering background. Under the special mining and geological condition mentioned above, UDEC numerical simulation software was applied to research the engineering problems, and results of numerical simulation were verified through the in-site measurement. The research results showed that during the fully mechanized caving mining in shallow and extremely thick seams, the inferior key strata affected by mining movement behaved in the mode of sliding instability and could not form the stable structure of the voussoir beam after breaking and caving. In addition, the main key strata behaved in the mode of rotary instability, and the caving rocks behind the goaf were gradually compacted because of the periodic instability of the main key strata. With the continuous advance of the working face, the abutment pressure of the working face was affected by the compound breakage and periodic instability of both the inferior key strata and the main key strata, and the peaks of the abutment pressure presented small-big-small-big periodical change characteristics. Meanwhile, the risk of rib spalling ahead of the working face presented different levels of acute or slowing trends. The actual measurement results of ground pressure in the working face showed that, in the working process, the first weighting interval of the inferior key strata was about 51 m and its average periodic weighting interval was about 12.6 m, both of which were basically consistent with the results of numerical simulation. The research has great significance in providing theoretical guidance and practical experience for predicting and controlling the ground pressure under the similar mining and geological conditions.

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The Effects of Backfill Mining on Strata Movement Rule and Water Inrush: A Case Study

Processes ◽

10.3390/pr7020066 ◽

2019 ◽

Vol 7 (2) ◽

pp. 66 ◽

Cited By ~ 4

Author(s):

Jian Hao ◽

Yongkui Shi ◽

Jiahui Lin ◽

Xin Wang ◽

Hongchun Xia

Keyword(s):

Longwall Mining ◽

Water Inrush ◽

Vertical Stress ◽

Strata Movement ◽

Ground Pressure ◽

In Situ Investigation ◽

Floor Failure ◽

Backfill Mining ◽

Failure Depth

Backfill mining is widely used to control strata movement and improve the stress environment in China’s coal mines. In the present study, the effects of backfill mining on strata movement and water inrush were studied based on a case study conducted in Caozhuang Coal Mine. The in-situ investigation measured abutment pressure distribution (APD), roof floor displacement (RFD), and vertical stress in the backfill area. Results are as follows: (i) The range and peak of APD, RFD, and vertical stress in the backfill area are smaller than in traditional longwall mining with the caving method. (ii) Backfill mining could change the movement form and amplitude of overburden and improve the ground pressure environment. (iii) Floor failure depth (FFD) is much smaller in backfill mining. Backfill mining can be an effective method for floor water inrush prevention.

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Current Situation and Prospect of Coal Backfill Mining Technology

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.421 ◽

2012 ◽

Vol 524-527 ◽

pp. 421-425 ◽

Cited By ~ 1

Author(s):

Wen Yu Lv ◽

Zhi Hui Zhang

Keyword(s):

Mining Method ◽

Abscission Layer ◽

Mining Technology ◽

Backfill Mining ◽

Paste Backfill ◽

Rock Movement ◽

Mining Capacity ◽

Mining Design

This paper introduces the classification of the coal backfill mining method and analyzes current technology statuses of several coal backfill mining technologies: waste backfill mining technology, paste backfill mining technology and abscission layer grouting backfill mining technology. Based on the analysis of current backfill mining technology statuses, this paper puts forth that the backfill mining technology should focus on the problem of the lack of coal backfill mining capacity, research on the role of backfill mining rock movement needing to be strengthened, filling efficiency and economy needed to improved through reasonable optimization of backfill mining parameter, so it can provide the theoretical basis for backfill mining design.

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Constitutive Model of Solid Backfill Materials and Numerical Simulation of Overburden Movement and Deformation in Backfill Mining

Shock and Vibration ◽

10.1155/2021/6619532 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Chao Ma ◽

Lianying Zhang ◽

Bing Li ◽

Xianbiao Mao

Keyword(s):

Constitutive Model ◽

Surface Subsidence ◽

Compaction Process ◽

Compaction Rate ◽

Key Strata ◽

Mining Depth ◽

Backfill Mining ◽

Backfill Materials ◽

Initial Compaction ◽

Mining Height

Solid backfill mining is an efficient and environmental-friendly coal mining technology, which can effectively solve the problems of coal gangue pollution, water resource loss, and surface subsidence. Based on the mechanical behavior of backfill materials in the compaction process, volume strain was used to express the deformation modulus, and a constitutive model of backfill materials was proposed in this study. The ABAQUS UMAT was used to develop the numerical calculation subroutine of the model. Finally, the rationality of the model was verified that simulated stress-strain curves of the backfill materials during the compaction process agree well with experiments. Based on the proposed constitutive model, the influence of three factors (the initial compaction rate of the filling body, the mining height, and the mining depth) on the key strata and surface subsidence was analyzed systematically. The results show that the initial compaction rate and the height of coal seams have significant influences on surface subsidence. When the thickness of topsoil is only changed and the structural composition and lithology of overburden are not changed, the mining depth has little influence on surface subsidence, but a significant influence on surface subsidence range. The influence of mining height and mining depth on the deformation of key strata of overburden and surface subsidence is approximately linear, while the influence of the initial compaction rate is nonlinear.

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A Method of Backfill Mining Crossing the Interchange Bridge and Application of a Ground Subsidence Prediction Model

Minerals ◽

10.3390/min11090945 ◽

2021 ◽

Vol 11 (9) ◽

pp. 945

Author(s):

Shuaigang Liu ◽

Jianbiao Bai ◽

Gongyuan Wang ◽

Xiangyu Wang ◽

Bowen Wu

Keyword(s):

Prediction Model ◽

Dynamic Change ◽

Simulation Software ◽

Surface Subsidence ◽

Ground Subsidence ◽

Mining Method ◽

Subsidence Prediction ◽

Probability Integral Method ◽

Backfill Mining ◽

Step Distance

The traditional backfill mining method is a technology developed by the general trend of green coal mining, but with a high cost and an impact on production efficiency. This paper proposes a structured backfill mining method with high-water materials and pillars. The evolution of roof pressure appearance is assessed through the sensor and monitoring system in the hydraulic support. The main roof fracture step distance is determined based on the roof structure characteristics of backfill mining, and the backfill step distance of underground structural backfill is 22.7 m considering the safety factor. Through the simulation results of Abaqus commercial simulation software, the roof subsidence evolution of different backfill schemes under temporary load and permanent load is compared, and the rationality of the backfill step distance is verified. Based on the probability integral method, the surface subsidence prediction model is proposed, then the final value and the maximum dynamic change value of the surface subsidence at the north and south ends of the interchange bridge by traditional mining and backfill mining are analyzed, which verifies the rationality of the structural backfill mining method.

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The Recent Progress China Has Made in the Backfill Mining Method, Part III: Practical Engineering Problems in Stope and Goaf Backfill

Minerals ◽

10.3390/min12010088 ◽

2022 ◽

Vol 12 (1) ◽

pp. 88

Author(s):

Haoxuan Yu ◽

Shuai Li ◽

Xinmin Wang

Keyword(s):

Recent Progress ◽

Mining Industry ◽

Research Progress ◽

Pipeline System ◽

Mining Method ◽

Continuous Innovation ◽

Backfill Mining ◽

Engineering Problems ◽

Practical Engineering ◽

Made In

With the continuous innovation and development of science and technology, the mining industry has also benefited greatly and improved over time, especially in the field of backfill mining. Mining researchers are increasingly working on cutting-edge technologies, such as applying artificial intelligence to mining production. However, in addition, some problems in the actual engineering are worth people’s attention, and especially in China, such a big mining country, the actual engineering faces many problems. In recent years, Chinese mining researchers have conducted a lot of studies on practical engineering problems in the stope and goaf of backfill mining method in China, among which the three most important points are (1) Calculation problems of backfill slurry transportation; (2) Reliability analysis of backfill pipeline system; (3) Stope backfill process and technology. Therefore, this final part (Part III) will launch the research progress of China’s practical engineering problems from the above two points. Finally, we claim that Part III serves just as a guide to starting a conversation, and hope that many more experts and scholars will be interested and engage in the research of this field.

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Stability Analysis and Confidence Level Evaluation of Backfill Mining under High and Steep Rock Slopes

Advances in Civil Engineering ◽

10.1155/2018/3029796 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12

Author(s):

Bo-yi Hu ◽

Xin-min Wang ◽

Shuai Li ◽

Jian-wen Zhao ◽

Nyandwe Musonda Eugénie

Keyword(s):

Stability Analysis ◽

Failure Probability ◽

Confidence Level ◽

Failure Surface ◽

Seismic Stability ◽

Normal Operation ◽

Mining Method ◽

Rock Slopes ◽

Destructive Effect ◽

Backfill Mining

To extract the 6.3 million tons of high-quality phosphate resources, a stability analysis and confidence level evaluation of backfill mining under high and steep rock slopes (HSRS) were conducted using the Slide software and a Monte Carlo simulation. The geological model of HSRS was constructed based on a geotechnical investigation. A series of laboratory tests were conducted to obtain the engineering parameters of the rock mass, and the mechanism of action of the backfill mining method was analyzed. After the stability analysis, the average safety factors of HSRS for normal operation are 1.575 (backfill method) and 1.509 (open-stope method), and for seismic conditions, they are 1.470 (backfill method) and 1.380 (open-stope method). According to the confidence level evaluation, the average failure probability of HSRS by using the backfill mining method is 0.0143. The results showed that using the backfill mining method under HSRS had better seismic stability and lower potential levels of destruction than using the traditional open-stope mining method. In addition, the backfill mining method can prevent the development of a circular failure surface, reduce the destructive effect of mining to a minimum, and maintain the lower failure probability of HSRS.

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