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.

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.

Study on the Relationship between Hydraulic Support on the Working Face with Large Mining Height and Surrounding Rock

2011 ◽  
Vol 328-330 ◽  
pp. 1671-1674
Author(s):  
Ying Ma ◽  
Sheng Zhong
Keyword(s):  
Coal Seam ◽  
Surrounding Rock ◽  
Hydraulic Support ◽  
Working Face ◽  
Safety Work ◽  
Immediate Roof ◽  
The Face ◽  
Large Mining Height ◽  
The Relationship ◽  
Mining Height

Using unified model and theory of rock pressure, the problems, such as caving of stope roof with large mining height and destruction of support, strata movement and surface subsidence, are unified analyzed and researched. The results show that: pressure shell is dynamic shell, which moves forward with the propulsion of working face; with the increase of mining height on the face, the height of fracture zone in coal seam increases, not continuously, but jumpily; with the increase of mining height, support load rises, but the degree of this rise decreases gradually, increased degree of immediate roof weight should be greater than that of given deformation pressure. The results provide necessary basis for reliability of hydraulic support on the working face with large mining height and safety work in the underground.

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 Analysis and Research on Control Technology of Large Mining Height Fully Mechanized Face and Roadway Surrounding Rock

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Kaiyi Xue ◽  
Liu Yang
Keyword(s):  
Raw Materials ◽  
Rapid Development ◽  
Storage Conditions ◽  
Primary Energy ◽  
Coal Industry ◽  
Mining Equipment ◽  
Mining Technology ◽  
Thick Coal Seam ◽  
Large Mining Height ◽  
Mining Height

Coal is important basic energy and important raw materials, the development of coal industry to support the rapid development of the national economy. In the 1950s and 1960s, the proportion of coal in China's primary energy production and consumption structure accounted for 90% and 80% respectively, and the proportion of coal in 2004 was 75.6% and 67.7% respectively. In recent years, with the rapid development of fully mechanized mining equipment manufacturing technology, fully mechanized mining equipment to heavy, strong and automated, so that the reliability of the equipment is guaranteed, a strong impetus to the development of large mining technology, new round of coal mining technology revolution, the current in the East, Jincheng and other mining areas have been the first in the thick coal seam f = 1.5-5 use of large mining height fully mechanized mining equipment, to achieve the highest efficiency, the lowest cost of tons of coal. The main points of this paper are: in the production of coal enterprises to improve the competitiveness of the coal market. Conditions and conditions of coal storage conditions should be allowed to give priority to the use of large mining and mining methods.

scholarly journals Determination of cyclic filling length in gob-side entry retained with roadside filling and its application

2020 ◽  
Author(s):  
Zizheng Zhang ◽  
Jianbiao Bai ◽  
Xianyang Yu ◽  
Weijian Yu ◽  
Min Deng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Difference Method ◽  
Suggested Method ◽  
Stress Difference ◽  
Thick Coal Seam ◽  
Mechanics Model ◽  
Working Face ◽  
Geological Conditions ◽  
The Relationship

Abstract Gob-side entry retained with roadside filling (GER-RF) plays a key role in achieving coal mining without pillar and improving the coal resource recovery rate. Since there are few reports on the cyclic filling length of GER-RF, a method based on the stress difference method is proposed to determine the cyclic filling length of GER-RF. Firstly, a stability analysis mechanics model of the immediate roof above roadside filling area in GER was established, then the relationship between the roof stress distribution and the unsupported roof length was obtained by the stress difference method. According to the roof stability above roadside filling area based on the relationship between the roof stress and its tensile strength, the maximum unsupported roof length and rational cyclic filling length of GER-RF. Combined with the geological conditions of the 1103 thin coal seam working face of Heilong Coal Mine and the geological conditions of the 1301 thick coal seam working face of Licun Coal Mine, this suggested method was applied to determine that the rational cyclic filling lengths of GER-RF were 2.4 m and 3.2 m, respectively. Field trial tests show that the suggested method can effectively control the surrounding rock deformation along with rational road-in support and roadside support, and improve the filling and construction speed.

scholarly journals Control of Gob-Side Roadway with Large Mining Height in Inclined Thick Coal Seam: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xie Fuxing
Keyword(s):  
Numerical Simulation ◽  
Coal Pillar ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Thick Coal Seam ◽  
Working Face ◽  
Rock Structure ◽  
Large Mining Height ◽  
Mining Height

The gob-side roadway of 130205, a large-mining-height working face in the Yangchangwan coal mine, was investigated in terms of the mine pressure law and support technology for large mining heights and narrow coal pillars for mining roadways. The research included field investigations, theoretical analysis, numerical simulation, field tests, and other methods. This paper analyzes the form of movement for overlying rock structure in a gob-side entry with a large mining height and summarizes the stress state and deformation failure characteristics of the surrounding rock. The failure mechanism of the surrounding rock of the gob-side roadway and controllable engineering factors causing deformation were analyzed. FLAC3D numerical simulation software was used to explore the influence law of coal pillar width, working face mining height, and mining intensity on the stability of the surrounding rock of the gob-side roadway. Ensuring the integrity of the coal pillar, improving the coordination of the system, and using asymmetric support structures as the core support concept are proposed. A reasonably designed support scheme for the gob-side roadway of the working face for 130205 was conducted, and a desirable engineering effect was obtained through field practice verification.

scholarly journals Fracture Mechanical Behavior of Cracked Cantilever Roof with Large Cutting Height Mining

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Zenghui Zhao ◽  
Wei Sun ◽  
Mingzhong Zhang ◽  
Xiaojie Gao ◽  
Shaojie Chen
Keyword(s):  
Fracture Mechanics ◽  
Cantilever Beam ◽  
Crack Size ◽  
Affected Area ◽  
Mechanics Model ◽  
Large Mining Height ◽  
Mining Disturbance ◽  
Seam Mining ◽  
Cutting Height ◽  
Mining Height

Accurately predicting the roof collapse span is crucial in ensuring the safe production of thick seam mining with large mining height, which is easy in forming a “cantilever beam” structure. Considering roof damage caused by roadway excavation and coal seam mining disturbance, the fracture mechanics model of large mining height roof cantilever beam with nonpenetrating cracks was established. The roof was divided into two parts: the crack-affected area and the crack-unaffected area. The analytical expression of the boundary between the two areas was established by fracture mechanics methods. Based on the boundary equation, the influences of crack size, crack inclination, roof lithology, and roof thickness on the roof crack-affected area were analyzed in detail. Finally, the accuracy of the theoretical model was verified by numerical experiments using the extended finite element method. The results demonstrate that the size of the area affected by the vertical crack increases with the increase of the crack size and the thickness of the roof. The influence of the crack decreases with the increase of roof lithology. The probability of early periodic collapse of a thin roof with the crack is increased. When the crack is completely located in the interior of the roof, the crack-affected area shrinks greatly with the decrease of the crack inclination. When the crack inclination is small, the crack will not cause the early collapse of the roof. Overall, the conclusions obtained are of great significance for predicting the collapse span of a cantilever roof with initial damage in large mining height.

Sign in / Sign up

Export Citation Format

Share Document