The Optimization Research of Wide Strip and Full-Pillar Mining under Villages

2012 ◽  
Vol 616-618 ◽  
pp. 406-410
Author(s):  
Gui Liu ◽  
Hua Xing Zhang ◽  
Jin Hui Chen ◽  
Chao Gao
Keyword(s):  
Surface Structures ◽  
Strip Mining ◽  
Mining Method ◽  
Sequence Optimization ◽  
Wide Strip ◽  
Deformation Limit ◽  
Working Face ◽  
Specific Analysis ◽  
Pillar Mining ◽  
Coal Pillars

By making full use of the advantages of strip mining method and full-pillar mining method, the wide strip and full-pillar mining method can achieve the aim of mining under villages. However, at the full-pillar mining stage, the difficulty in managing several workfaces which are at work at the same time still exists. To improve the wide strip and full-pillar mining method’s applicability, an optimization of extraction sequence for coal pillars instead of the multi-working-face is put forward at the stage of full-pillar mining, and in the case of the deformation limit of surface structures is satisfied, to extract all the coal pillars which are under villages. By specific analysis of the extraction sequence optimization of the coal pillars in No.1 mine under Qian Xudapo village which belongs to Chang Chun coal Co., LTD., a better result is got which also acts a technological reference for the extraction under villages.

scholarly journals Conversion mechanism of a continuous pressure arch structure in strip filling mining

2021 ◽  
Vol 14 (18) ◽  
Author(s):  
Xiaoping Shao ◽  
Long Wang ◽  
Xin Li ◽  
Zhiyu Fang ◽  
Bingchao Zhao ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Theoretical Analysis ◽  
Shaanxi Province ◽  
Strip Mining ◽  
Second Stage ◽  
The Third ◽  
Working Face ◽  
Third Stage ◽  
Arch Structure ◽  
Coal Pillars

AbstractStrip mining is the key technology to solve the problem of coal mining under water, so mastering the law of overburden load transfer in strip mining is the key to safe production in working face. We studied it in the context of the shallow seam No. 3 in the Shanghe Coal Mine (northern Shaanxi Province, China) through similarity simulation and field measurement analysis. A theoretical analysis, based on the concept of pressure arch, allowed the establishment of a continuous arch theoretical model for the strip coal pillars (or filling bodies) of the mine. A similar simulation study on strip filling and staged mining has previously shown that, in a first stage, the overlying strata load is mainly transferred to the remaining strip coal pillars; in a second stage, this load is mainly sustained by the odd-numbered strip coal pillars; finally, in a third stage, this load is mainly sustained by the first-stage strip filling body, while the third-stage filling body is not loaded. Our theoretical analysis showed that, during the first stage, the overlying rock load outside the arch was mainly sustained by the arch structure, while that inside of the arch was sustained by the filling body; in the second stage, the arch structure lost stability during the recovery of the even-numbered coal pillars and the arch axis developed upward, leading to the formation of a new arch with an odd number of coal pillars as the arch foot; in the third stage, after the recovery of the odd-numbered coal pillars, a new arch was formed. The arch foot of the new supporting structure was represented by the first-stage filling body; moreover, the load was mainly borne by the second-stage filling body, ensuring the stability of the overburden rock after mining. The theoretical analysis revealed that the pillar or filling body only bears part of the overburden load in strip filling mining. The pillar (filling body) load in correspondence of working face 3216 during each stage of filling was measured and analyzed, proving a continuous arch structure transformation between the pillar and the filling body. Finally, we verified the reliability of the proposed theoretical model.

scholarly journals A protective seam mining method by cutting roof with chainsaw arm machine

2020 ◽  
Author(s):  
Tiejun Kuang ◽  
Yang Tai ◽  
Bingjie Huo ◽  
Binwei Xia ◽  
Yanqun Zhang ◽  
...  
Keyword(s):  
Lower Layer ◽  
Mining Method ◽  
Coal Seams ◽  
Working Face ◽  
Protective Seam ◽  
Mining Pressure ◽  
Coal Pillars ◽  
Residual Coal ◽  
Seam Mining ◽  
Protective Seam Mining

Abstract Multiple-layered coal seams widely exist in main coal mining areas of China. When these coal seams are exploited, the pillar mining method is always employed. This leads to many coal pillars left in the upper coal seams as a protective barrier. As a result, these residual pillars will not only cause the loss of coal resources but also could trigger environmental issues and a serious of mine disasters. A theoretical model was built to analyse the effect of the residual pillars. From the theoretical model, it was found that four stress concentration areas were formed by the upper residual coal pillars. To address the issues of the residual coal pillars, Datong Coal Mine Group has developed an innovative technology of the roof cutting with a chainsaw. A new protective coal seam mining method using chainsaw roof-cutting technology is introduced. A numerical model is constructed to analyse the mining pressure distribution law in working face within the lower layer coal seam. From the numerical simulation, the new protective layer mining method could reduce about 15.2% of the advancing stress, which contributes a lot to controlling the mining pressure within the lower layer. The field measurement showed that the hydraulic support utilised at the site was at lower pressure levels, which proves the new protective seam mining method can significantly reduce the working face pressure.

scholarly journals Research on stress release for the gob-side roadway using the roof-cutting technology with a chainsaw arm

2020 ◽  
Vol 7 (3) ◽  
pp. 191663
Author(s):  
Yang Tai ◽  
Bin Yu ◽  
Binwei Xia ◽  
Zhao Li ◽  
Hongchu Xia
Keyword(s):  
Numerical Analysis ◽  
Coal Pillar ◽  
Deformation And Failure ◽  
Hard Roof ◽  
Working Face ◽  
Stress Relieving ◽  
Cutting Experiment ◽  
Pillar Mining ◽  
Coal Pillars ◽  
Cutting Height

The narrow pillar mining method is widely adopted for working faces in coal mines. However, in cases of an overlying hard roof, a suspended triangle roof plate or a cantilever will be formed near the goaf. At this point, the coal pillar extrusion and serious deformation will occur in the gob-side roadway. In order to mitigate the problem, the roof-cutting technology with a chainsaw arm and its equipment have been developed. In this paper, based on the analysis of deformation and failure characteristics of 2312 roadway, which is close to the goaf of 2311 working face in Tashan Coal, the roof-cutting technology with a chainsaw arm was chosen to be applied in 2311 roadway. Then, the roof-cutting process and the load acting on the coal pillar were discussed and analysed. A numerical model was established to analyse the stress releasing effects after roof cutting. Moreover, the roof-cutting height and the support parameters of the roadway were optimized through numerical analysis and the results manifested that the roof cutting was the most effective when the roof-cutting height was 6.4 m. After roof cutting, the vertical stresses within the coal pillars were lowered by about 25.0%. Finally, the roof-cutting experiment was carried out in the 2311 roadway in Tashan Coal Mine. The on-site roof-cutting depth was 6.4 m and the roof-cutting width was 42 mm guided by the numerical analysis. To verify the stress-relieving effects, the borehole stress meters were applied to monitor the peak advancing stresses of narrow pillars at various depths. The measured results indicated that the peak advancing stresses decreased by 22.8% on average, and therefore, roof cutting and stress releasing effects were achieved.

scholarly journals Energy Evolution Pattern and Roof Control Strategy in Non-Pillar Mining Method of Goaf-Side Entry Retaining by Roof Cutting—A Case Study

2019 ◽  
Vol 11 (24) ◽  
pp. 7029 ◽  
Author(s):  
Lifeng Li ◽  
Gan Li ◽  
Weili Gong ◽  
Jiong Wang ◽  
Huilin Deng
Keyword(s):  
Energy Density ◽  
Large Deformation ◽  
Control Strategy ◽  
Calculation Model ◽  
Surrounding Rock ◽  
Mining Method ◽  
Energy Evolution ◽  
Working Face ◽  
Evolution Pattern ◽  
Pillar Mining

This article focuses on the energy density alteration during non-pillar mining method of goaf-side entry retaining by roof cutting (GERRC) and adjacent working face mining. We also studied the support control strategy of goaf-side roadway. Numerical calculation model is established, and the parameters of the model are verified by the measured advance abutment pressure and numerical solution. Based on the numerical model, the energy density during mining is studied. It is found that the whole energy evolution pattern of the goaf side entry during the two adjacent working face mining includes: the original rock energy, the advance energy of the current working face, the dynamic lateral abutment energy caused by strata movement, the lateral abutment energy of the adjacent working face. The support body failure and surrounding rock large deformation phenomenon often occur in goaf side roadway, which is influenced by multiple energy disturbances. Research shows that strong stress disturbance of surrounding rock generates in front of the working face 23 m and behind of working face 60 m in GERRC method. In the second goaf-side entry retaining, the range is in front of the working face 47 m. The evolution law of energy field puts forward the strategy of using the high constant resistance and large deformation (CRLD) anchor cable and procured preferable effect.

Study on the Monitoring Method of Overburden Failure of Shallow Wongawilli Mining Working Face

2011 ◽  
Vol 422 ◽  
pp. 158-163
Author(s):  
Bin Zhang ◽  
Wen Li ◽  
Shao Gang Li ◽  
Jun Ying Zhang
Keyword(s):  
Mining Area ◽  
Overburden Rock ◽  
Mining Method ◽  
Stress Monitoring ◽  
Monitoring Methods ◽  
Monitoring Method ◽  
Working Face ◽  
Coal Pillars ◽  
Subsidence Monitoring ◽  
Overburden Strata

Through the practice and improvement of Wongawilli Mining method in Shendong Mining Area, it created Shendong Characteristic short wall mechanize room mining method. Due to the shallow coal seam, the fracture zones throughout the bedrock directly after the mining, therefore the bending sinking belt didn’t exist; the conventional "three zones" theory couldn’t explain the overburden rock deformation damage rule of this situation perfectly. In order to monitor the damage of overburden strata, based on the analysis of coal pillars stability in Wongawilli working face, the paper puts forward 3D monitoring methods of overburden strata damage as follows: underground borehole stress monitoring, roof separated strata and layer's internal monitoring, surface subsidence monitoring. The set of monitoring method can monitor the instability of coal pillars, roof caving, production of separated strata in the roof, overburden rock damage and subsidence, the study is of reference and significance.

Research Progress and Prospect of the Control Technology for Mining Subsidence

2011 ◽  
Vol 361-363 ◽  
pp. 161-165
Author(s):  
Cheng Hui Ren ◽  
Wen Sheng Liu ◽  
Huan Wang
Keyword(s):  
Research Area ◽  
Surface Structures ◽  
Mining Subsidence ◽  
Research Progress ◽  
Control Technology ◽  
Mining Method ◽  
Main Research ◽  
Pillar Mining ◽  
Mining Methods ◽  
Overlying Strata

The control technology for mining subsidence is the main research area of mining subsidence. Its objective is to study and select mining methods appropriate for reducing the surface and overlying strata subsidence and protecting the surface structures. Referring to the analysis of references, the control technology for mining subsidence is discussed from several aspects including backfill mining method, partial mining method, backfill the collapsed cavities in overlying strata, harmonized mining method and 3-step mining method, stripping mining-goaf grouting, and backfill-strip pillar mining. The developing trend of the control technology is also prospected.

scholarly journals Research and Application of an Innovative 110 Mining Method in Gob-Side Half Coal Rock Entry Retaining

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Eryu Wang ◽  
Xiangdong Chen ◽  
Xiaojie Yang
Keyword(s):  
Recovery Rate ◽  
Mine Pressure ◽  
Mining Method ◽  
Time Consumption ◽  
Coal Recovery ◽  
Working Face ◽  
Constant Resistance ◽  
Movement Characteristic ◽  
Coal Rock ◽  
Maximum Subsidence

In order to solve the problems of the high cost and time consumption of half coal rock entry driving, low coal recovery rate, and stress concentration on filling support body of retained entry along gob, the innovative 110 mining method based on pressure relief by roof cutting was adopted in 6302 thin coal seam working face of Baoshan Coal Mine. First the technical principle and key technology of this mining method was presented. Then, through theoretical analysis and calculation, engineering experience, and field test, the key parameters such as the length of constant resistance anchor cable, the cutting angle and height of presplitting blasting, the charge structure, and the blocking-gangue support structure were determined and conducted in the retained entry. The broken expanded coefficient varying law of caved gangue with time and space was obtained, which revealed roof movement characteristic. The displacement monitoring curve of the roof and floor indicated that the maximum subsidence of the roof was about 150 mm and the maximum amount of floor heaving was 100 mm, which were quite small. The field monitoring data indicated that the entry retaining effect is good, which indicated that the innovative 110 mining method can be an effective way for reducing the high cost and time consumption of half coal rock entry driving, enhancing the coal recovery rate and preventing the dynamic mine pressure disasters.

scholarly journals Gob-Side Entry Retaining Involving Bag Filling Material for Support Wall Construction

2020 ◽  
Vol 12 (16) ◽  
pp. 6353
Author(s):  
Zhaowen Du ◽  
Shaojie Chen ◽  
Junbiao Ma ◽  
Zhongping Guo ◽  
Dawei Yin
Keyword(s):  
Field Tests ◽  
Filling Material ◽  
Construction Technology ◽  
Working Face ◽  
Support Resistance ◽  
Pillar Mining ◽  
High Production ◽  
Wall Construction ◽  
Thin Seam ◽  
Seam Mining

Gob-side entry retaining, also termed as non-pillar mining, plays an important role in saving coal resources, high production and efficiency, extending the service life of mine and improving the investment benefit. Herein, a gob-side entry retaining method involving the use of bag filling material for wall construction is proposed based on the thin seam mining characteristics. First, a gob-side entry retaining mechanical model is established, and the side support resistance of the 8101 working face is calculated. The mechanical properties of the bag material are investigated through experiments, and the construction technology of the gob-side entry retaining approach involving the use of bag filling material for wall construction is introduced. The deformation on the two sides, the roof and floor of the roadway, are simulated via numerical methods and monitored during field tests. The results show a small control range for the deformations and a good roadway retention effect, thereby proving the feasibility of the bag filling material for wall construction. This study provides a reference for the development of gob-side entry retaining mining for thin coal seams.

Optimal Design of Working Face Ventilating System of Huoerxinhe Company

2014 ◽  
Vol 998-999 ◽  
pp. 446-449
Author(s):  
Li Ping Yang ◽  
Wei Qiao ◽  
Hou Quan Zhou
Keyword(s):  
Optimal Design ◽  
Coal Mine ◽  
Efficient Production ◽  
Ventilation Mode ◽  
Working Face ◽  
Mode 2 ◽  
Waste Air ◽  
Type Mode ◽  
Coal Pillars ◽  
Tunneling Engineering

In order to guarantee the safe and efficient production of coal mine of Huoerxinhe Company, for the problems of gas exceeding limitation, excavating replacement tension, resource waste air leaking and so on, the ventilation mode was optimized and Y type ventilation mode was adopted. Practices indicate that this ventilation mode is entirely feasible on working face of Huoerxinhe Company. Through this mode, we can (1) decrease the tunneling engineering quantity, improve the excavating replacement tension of double U type mode; (2) reduce the protective coal pillars to cut down resource waste; (3) solve the problem of gas exceeding limitation on upper corner thoroughly.

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