Determination the cutting height of top-coal caving with great mining height in extra thick coal seam

2014 ◽  
pp. 71-76
Keyword(s):  
Coal Seam ◽  
Thick Coal Seam ◽  
Cutting Height ◽  
Mining Height

A Study on the Roof Fracture Mechanism of Large Cutting Height Workface in Shallow Thick Coal Seam

2011 ◽  
Vol 347-353 ◽  
pp. 183-188 ◽  
Author(s):  
Ping Wei Xing ◽  
Xuan Min Song ◽  
Yu Ping Fu
Keyword(s):  
Coal Seam ◽  
Mechanical Model ◽  
Calculation Formula ◽  
Thick Coal Seam ◽  
Key Stratum ◽  
Horizontal Pressure ◽  
Working Resistance ◽  
Cutting Height ◽  
Theoretical Results ◽  
Mining Height

Based on the high mining height of large cutting height workface in shallow thick coal seam and the few falling waste rock in goaf, the key roof can not be supported effectively, the facture mechanical model of key roof was established. The theoretical calculation formula of key stratum fracture step and working resistance of support were obtained by using fracture mechanics. The results show that the fracture step of key roof relate to not only the mechanical character of key roof and the load of overlaying rock seam, but also the working resistance of support and horizontal pressure in key roof. The reasonable working resistance of support and the step of roof fracture were analyzed in 1-2coalmine 51104 face of a mine in Dongsheng area. The theoretical results are well agreeable with the field measured results.

scholarly journals Cutting-Caving Ratio Optimization of Fully Mechanized Caving Mining with Large Mining Height of Extremely Thick Coal Seam

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Kai Wang ◽  
Tong Zhao ◽  
Kaan Yetilmezsoy ◽  
Xiaoqiang Zhang
Keyword(s):  
Coal Seam ◽  
Influencing Factors ◽  
Recovery Rate ◽  
Engineering Application ◽  
Thick Coal Seam ◽  
Coal Wall ◽  
Large Mining Height ◽  
Cutting Height ◽  
The Relationship ◽  
Mining Height

Serious rib spalling and low recovery rate problems caused by the poor top-coal caving property (TCCP) were investigated in fully mechanized caving mining with large mining height (FMCMLMH) of extremely thick coal seam. For this aim, theoretical calculation, numerical simulation, and engineering application were applied to study the reasonable cutting-caving ratio under the influence of different factors. The calculation formula of reasonable cutting height in FMCMLMH was obtained, and effective factors were determined. Moreover, Ft (the top-coal yield failure coefficient) and Fw (the coal wall yield failure coefficient) were defined, and each factor was fitted by using a linear regression equation. The minimum Ft of fully fractured top coal was 0.6, and the main influencing factors were buried depth and Protodyakonov coefficient. The maximum Fw of the stable coal wall was 1.5, and the main influencing factors were buried depth and cutting height. According to the relationship between coal wall stability and recovery rate, the relationship between coal seam strength and top-coal thickness at different cutting heights was obtained, and the mining zone was divided into four subzones. Engineering application showed that the optimal cutting height of Xiegou Coal Mine was 4 m, the cutting-caving ratio was 1 : 2.75, and the recovery rate could reach more than 85%, which was the most reasonable.

scholarly journals Study on Water Disaster Prevention and Control Technology under Condition of Extra-thick Coal Seam with Slicing Fullmechanized Caving Mining

2018 ◽  
Vol 53 ◽  
pp. 04024
Author(s):  
Jianghua Li ◽  
Yuguang Lian ◽  
Hongjie Li
Keyword(s):  
Coal Seam ◽  
Field Observation ◽  
Prevention And Control ◽  
Control Method ◽  
Disaster Prevention ◽  
Cretaceous Rock ◽  
Thick Coal Seam ◽  
And Control ◽  
Water Disaster ◽  
Mining Height

Some coal seams belong to cretaceous strata in the east of Inner Mongolia, China. There are obvious differences of rock characteristics and mechanical properties between Cretaceous and Carboniferous- Permian strata. The overburden failure characteristics of extra-thick coal seam with slicing full-mechanized caving mining are studied through rock mechanics experiment, field observation and theoretical analysis and so on. Water disaster prevention and control method of roof and goaf is put forward under the condition of extra-thick coal seam with slicing full-mechanized caving mining. The final research results include: (1) The rock of cretaceous strata has low strength and soft characteristic, its stability is very poor, cretaceous rock belongs to weak type; (2) Under the condition of extra-thick coal seam with slicing full-mechanized caving mining, the ratio between caving zone and mining height of field observation result is 4.58～4.74, the observation results of two boreholes are close; (3) It is significantly effective to prevent and control water disaster from goaf through roof hole drainage method, coal and rock safety pillar remain method is used to limit mining height under the Tertiary gravel aquifer, which makes the working face exploit safely.

Numerical Analysis of Influencing Factors of Stability in Thick Coal Seam Mining Roadway

2012 ◽  
Vol 256-259 ◽  
pp. 1453-1457
Author(s):  
Zhi Hua Li ◽  
Xin Zhu Hua ◽  
Ke Yang ◽  
Ruo Jun Zhu ◽  
De Sheng Zhou
Keyword(s):  
Coal Seam ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Rock Body ◽  
Thick Coal Seam ◽  
Mining Depth ◽  
Working Face ◽  
Face Length ◽  
Seam Mining ◽  
Mining Height

The FLAC-3D software was used to study the surrounding rock displacement and the side abutment pressure distribution laws about roadway in thick coal seam. Based on this model, through change the mining height, working face length and mining depth, the differences of roadway underground pressure characteristics were analyzed between thick coal seam working face and normal working face. The results indicate that: ①the displacement of roadway surrounding rock increases with the increase of mining depth and mining height, the closer to the coal wall the larger of the increase range of roadway displacement. ②the peak of side abutment pressure increases with the increase of mining depth and mining height, the peak district of the stress will move toward the inner department of rock body. ③ the effect of working face length on the roadway displacement and the side abutment pressure is very feeble.

Roadway Supporting Technology in Fully Mechanized Workface with Large Mining Height of Specially Thick Coal Seam in Datong Mining Area

2012 ◽  
Vol 204-208 ◽  
pp. 1611-1616 ◽  
Author(s):  
Guo Liang Lu ◽  
Chen Wang ◽  
Yao Dong Jiang ◽  
Hong Wei Wang
Keyword(s):  
Coal Seam ◽  
High Reliability ◽  
Soft Rock ◽  
High Strength ◽  
Mining Area ◽  
Thick Coal Seam ◽  
Roadway Safety ◽  
Large Mining Height ◽  
Soft Rock Roadway ◽  
Mining Height

Aimed at the supporting problems in the fully mechanized roadway with large mining height of the specially thick coal seam in workface 8105 in Tashan coal mine, the “three highs with one low” supporting technology of high strength, high stiffness, high reliability and low support density was adopted to solve the roadway supporting problems of specially high coal side and specially large section and effectively control the surrounding rock deformation and ensure the roadway safety. It also increased the roadway excavation speed which made good conditions for fast advance of the fully mechanized workface, and it made the soft-rock roadway supporting technology in Datong mine area develop into a new level.

scholarly journals Research on the Influence of Mining Height on the Movement Characteristics of Overlying Strata during Extremely Thick Coal Seam Fully Mechanized Sublevel Caving Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yongkang Yang ◽  
Jie Wei ◽  
Chenlong Wang
Keyword(s):  
Coal Seam ◽  
Physical Simulation ◽  
Quadratic Polynomial ◽  
Tensile Failure ◽  
Thick Coal Seam ◽  
Sublevel Caving ◽  
Height Increase ◽  
Supporting Force ◽  
Mining Height ◽  
Overlying Strata

The study of the effects of mining height on overlying strata movement and underground pressure characteristics during extremely thick coal seam fully mechanized sublevel caving mining is very important for choosing the reasonable mining height and the support. Based on the geological setting and mining conditions at the Xiegou Coal Mine, the results of the physical simulation test and the numerical simulation technology will be used. Some conclusions can be drawn as follows: (1) With the mining height increase, the top coal gradually converted from tensile failure to shear damage, and the coal wall gradually transformed from shear failure to tensile damage. (2) When the mining height is 7.5 m, the full-seam collapse distance, the immediate first weighting interval, and the main roof first weighting length are shorter than that when the mining height is 4m, and the periodic weighting length for the two mining heights is almost the same. (3) With mining height increase, the initial mining stage and the transition stage become shorter, and the production rates become better. (4) The law of the abutment pressure peak and the sphere of influence increase slightly, and the working resistance of support needed to be strengthened. (5) The subsidence quantity of the top coal in the control area increases along with the mining height in a quadratic polynomial way but decreases along with the initial supporting force in a negative logarithmic rule. (6) After assigning the subsidence, the regression relation between the initial supporting force and the mining height is a quadratic polynomial.

Narrow Pillar Mining Technology of Fully Mechanized Sublevel Caving Faced with Great Cutting Height in Tashan Mine

2013 ◽  
Vol 295-298 ◽  
pp. 2950-2953
Author(s):  
Yuan Fan ◽  
Wei Dong Pan ◽  
Zhao Hui Wang ◽  
De Lin Li ◽  
Wen Bo Song
Keyword(s):  
Coal Seam ◽  
Reference Value ◽  
Mining Technology ◽  
Mining Technique ◽  
Sublevel Caving ◽  
Pillar Mining ◽  
Coal Pillars ◽  
Cutting Height ◽  
Theory Research ◽  
Mining Height

Based on the great thickness of coal seam in Tashan Mine, narrow pillar mining technology was adopted to liberate more coal resources from coal pillars. In this paper, the research status of narrow pillar technology was analyzed, and the main problems of the narrow pillar mining technique were solved by theory research. The method and technical route of this study was offered in final. The results have great reference value to the fully mechanized sublevel caving with great mining height in similar conditions.

scholarly journals Cooperative Control Mechanism of Long Flexible Bolts and Blasting Pressure Relief in Hard Roof Roadways of Extra-Thick Coal Seams: A Case Study

2021 ◽  
Vol 11 (9) ◽  
pp. 4125
Author(s):  
Zhe Xiang ◽  
Nong Zhang ◽  
Zhengzheng Xie ◽  
Feng Guo ◽  
Chenghao Zhang
Keyword(s):  
Coal Seam ◽  
Cooperative Control ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Hole ◽  
Coal Seams ◽  
Thick Coal Seam ◽  
Structure Damage ◽  
Hard Roof

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

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