scholarly journals Accurate Perception of Rock Strata Movement for Environmental Protection in Coal Mining: Taking Thick and Hard Roof Cooperative Control as an Example

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Tong Zhao ◽  
Changyou Liu ◽  
Kaan Yetilmezsoy ◽  
Majid Bahramian ◽  
Peilin Gong
Keyword(s):  
Environmental Protection ◽  
Coal Mining ◽  
Physical Simulation ◽  
Environmentally Friendly ◽  
Industrial Test ◽  
Confined Water ◽  
Hard Roof ◽  
Key Stratum ◽  
Accurate Perception ◽  
Rock Strata

Accurate perception of the key stratum instability can improve the safety of coal mining and also provide a basis for alleviating overlying rock strata destruction and environmental disturbance. To efficiently evaluate the instability of the key stratum and its threat to safe mining and environmental protection, the fracture characteristics and weakening mechanisms were studied through physical simulation, theoretical analysis, and field measurement. A scheme and the parameters of confined blasting in water-filled deep hole presplit technology (CBWDHPT) for thick and hard roof (THR) weakening were proposed. Research studies showed that, after the THR fractured into large blocks, the subsequent sliding instability induced serious support-crushing accidents; however, increasing the support strength could only provide limited control. Confined water and infiltrated modified rock mass functioned as the transfer load medium of the explosives, and the CBWDHPT fully utilized high explosion energy to break rocks. Consequently, the collapse and filling of the immediate roof and low-positioned THR, as well as the timely cutting off the middle-positioned THR, could be realized, which alleviated the migration space of THR blocks, overlying strata destruction, and earth-surface step subsidence. Finally, the environmentally friendly strategy (including the CBWDHPT and hydraulic support optimization) for overlying rock strata protection was proposed. In the industrial test, the THR was broken into blocks of different sizes after utilizing the CBWDHPT, and the support working resistance was significantly decreased. It was concluded that the environmentally friendly strategy could effectively reduce the risk of overlying rock strata destruction.

scholarly journals Application and Development of an Environmentally Friendly Blast Hole Plug for Underground Coal Mines

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Donghui Yang ◽  
Yixin Zhao ◽  
Zhangxuan Ning ◽  
Zhaoheng Lv ◽  
Huafeng Luo
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Low Cost ◽  
Blast Hole ◽  
Environmentally Friendly ◽  
Test System ◽  
Industrial Test ◽  
Labor Intensity ◽  
Rock Blasting ◽  
Hopkinson Pressure Bar ◽  
The Impact

Drilling and blasting technology is one of the main methods for pressure relief in deep mining. The traditional method for blasting hole blockage with clay stemming has many problems, which include a large volume of transportation, excess loading time, and high labor intensity. An environmentally friendly blast hole plug was designed and developed. This method is cheap, closely blocks the hole, is quickly loaded, and is convenient for transportation. The impact test on the plug was carried out using an improved split Hopkinson pressure bar test system, and the industrial test was carried out in underground tunnel of coal mine. The tests results showed that, compared with clay stemming, the new method proposed in this paper could prolong the action time of the detonation gas, prevent premature detonation gas emissions, reduce the unit consumption of explosives, improve the utilization ratio, reduce the labor intensity of workers, and improve the effect of rock blasting with low cost of rock breaking.

scholarly journals Movement Laws of Overlying Strata above a Fully Mechanized Coal Mining Face Backfilled with Gangue: A Case Study in Jiulishan Coal Mine in Henan Province, China

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Zhengkai Yang ◽  
Zhiheng Cheng ◽  
Zhenhua Li ◽  
Chunyuan Li ◽  
Lei Wang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Main Roof ◽  
Surrounding Rock ◽  
Surface Subsidence ◽  
Key Strata ◽  
Key Stratum ◽  
Mining Face ◽  
Failure Depth ◽  
Gangue Backfilling ◽  
Overlying Strata

The aim of this study is to obtain movement laws of overlying strata above a fully mechanized coal mining face backfilled with gangue and solve the problem of surface subsidence during coal mining. This study was carried out based on gangue backfilling mining of Jiulishan Coal Mine (Jiaozuo City, Henan Province, China) from the perspectives of deformation of backfilled gangue under compaction, surrounding rock of a stope, and activities of key strata. The method combining with rock mechanics, viscoelastic mechanics, control theory of rock mass under mining, and numerical simulation was used based on physical and mechanical characteristics of backfilled gangue. On this basis, the research analyzed the temporal-spatial relationships of activities of surrounding rock of the stope, compressive deformation of backfilling body, failure depth of the floor, deformation characteristics of the main roof with laws of surface subsidence. The movement characteristics of overlying strata above the fully mechanized coal mining face backfilled with gangue and the traditional fully mechanized mining face were compared. It is found that, under the same conditions of overlying strata, movement laws of overlying strata are mainly determined by the mining height of coal seams and the heights of a caving zone and a fracture zone are nearly linearly correlated with the mining height. Through analysis based on thin-plate theory and key stratum theory, the location of the main roof of the fully mechanized coal mining face backfilled with gangue in coal seams first bending and sinking due to load of overlying strata was ascertained. Then, it was determined that there are two key strata and the main roof belongs to the inferior key stratum. By using the established mechanical model for the main roof of the fully mechanized coal mining face backfilled with gangue and the calculation formula for the maximum deflection of the main roof, this research presented the conditions for breaking of the main roof. In addition, based on the theoretical analysis, it is concluded that the main roof of the fully mechanized coal mining face backfilled with gangue does not break, but bends. The numerical simulation results demonstrate that, with the continuous increase of strength of backfilled gangue, the stress concentration degree of surrounding rock reduces constantly, so does its decrease amplitude. Moreover, the compressive deformation of backfilling, failure depth of the floor, and bending and subsidence of the main roof continuously decrease and tend to be stable. The mechanical properties of backfilling materials determine effects of gangue backfilling in controlling surface subsidence. Gangue backfilling can effectively control movement of overlying strata and surface subsidence tends to be stable with the increase of elastic modulus of gangue.

scholarly journals The Experience of Legal Regulation of Reclamation of the Developed Space by the Leading Countries of Coal Mining

2020 ◽  
Vol 174 ◽  
pp. 02012
Author(s):  
Irina Verchagina ◽  
Irina Kolechkina ◽  
Elena Shustova
Keyword(s):  
United States ◽  
Environmental Protection ◽  
Coal Mining ◽  
Mineral Resources ◽  
The United States ◽  
Legal Regulation ◽  
Regulatory Framework ◽  
The Us

The article presents the results of a study of the regulatory framework and the experience of regulating the issues of reclamation of the developed space of the leading coal mining countries - the United States and China. The laws of China on mineral resources and environmental protection, the US practice of creating a system for restoring disturbed space as a result of mining, are examined

New Technology of Surface Subsidence Control and Environmental Protection Research in Coal Mining Region

2014 ◽  
Vol 675-677 ◽  
pp. 1385-1394
Author(s):  
Cheng Rong Jiang ◽  
Liu Yang ◽  
Hao Xie ◽  
Hua Yi Huang ◽  
De Ke Sun
Keyword(s):  
Coal Mining ◽  
New Technology ◽  
Mining Area ◽  
Industrial Test ◽  
Surface Subsidence ◽  
High Concentration ◽  
Geological Conditions ◽  
Surface Subsidence Control ◽  
Fissure Water ◽  
Overlying Strata

In combination with the geological conditions of Tie'er mining area in Tangshan coal mining, this paper not only analyzes the evolution of overlying strata structure in stope and the development law of overlying strata separation, also proposes a new continuous grouting technology with large flow and high concentration slurry. The industrial test showed that, when the grout-mining ratio of the whole mining area is 25.3%, the reducing subsidence ratio is 51.5%, the effect of reducing the surface subsidence is good. According to the chemical analysis of water quality ingredients of slurry, the test result showed, heavy metals contents in fly-ash slurry water do not exceed the standard, which has no bad effect on the fissure water in the bedrock.

scholarly journals The corresponding relationship between the change of goaf pressure and the key stratum breaking

2019 ◽  
Vol 16 (5) ◽  
pp. 913-925
Author(s):  
Jianlin Xie ◽  
Jialin Xu
Keyword(s):  
Rock Mass ◽  
Internal Pressure ◽  
Load Transfer ◽  
Physical Simulation ◽  
Field Measurements ◽  
Monitoring Methods ◽  
Key Stratum ◽  
Working Face ◽  
Actual Rock ◽  
Overlying Strata

Abstract Existing studies mostly focus on the stress change of coal in front of a goaf, but rarely conduct field monitoring on the internal pressure of a goaf, primarily due to the complex environment and other restrictive conditions of goafs. This paper first used physical simulation to monitor and analyze the internal pressure of goaf and found that goaf pressure presented a stepwise growth with the key stratum breaking. In addition, field measurements were conducted to monitor the goaf pressures of two different working faces. Goaf pressures both presented linear growth with the advance of the working face. According to comparative analysis, there were some differences between the two monitoring methods in terms of the corresponding relationship. This reflects that in the actual rock mass, after the breaking of a key stratum, the loads of the strata under its control are not transferred to the goaf instantaneously and load transfer characteristics are probably related to roof separation distribution characteristics of overlying strata, the bulking characteristics of caved rock mass, lateral stress limitation and other factors. The results of this study will offer some guidance for studies on the movement laws of overlying strata and the load transfer of overlying strata above goafs.

The Environmental Protecting Gourd Packaging Material

2013 ◽  
Vol 329 ◽  
pp. 118-121
Author(s):  
Yan Liang
Keyword(s):  
Environmental Protection ◽  
Present Status ◽  
Environmentally Friendly ◽  
Environmental Problems ◽  
Packaging Material ◽  
Packaging Materials ◽  
Global Environmental Problems ◽  
Global Environmental ◽  
Packaging Industry

With the raise of serious global environmental problems, it has become an important theme of the development of the packaging industry to research environmentally friendly packaging materials. Gourd is a kind of natural packaging material.This paper studied the gourds properties as the packaging material.It reported the present status of gourds processing which includes the dispose of the material and the ornament of the material.It also reported the relations between gourds and packaging which include the materials application in liquid packaging area and solid packaging area.At last ,it demonstrates natural gourd can be used and developed as native materials in environmental packaging materialand it advocates enlarging the scope of gourdsapplication in packaging area to conform to the trend of the development of green environmental protection industry.

Analysis of “Low-Carbon Tourism" Development Problem Based on the Environmental Protection

2013 ◽  
Vol 807-809 ◽  
pp. 998-1001
Author(s):  
Hong Liu ◽  
Ming Chong Gu
Keyword(s):  
Environmental Protection ◽  
Human Ecology ◽  
Tourism Development ◽  
Environmentally Friendly ◽  
Tourism Industry ◽  
Construction Process ◽  
Low Carbon ◽  
Way Of Life ◽  
Strategic Direction ◽  
New Type

With the advancement of human ecology civilization construction process, low-carbon economies is increasingly influence and guide the human production and way of life. Since the carbon tourism been put forward at the end of 2009, it received widespread attention at home and abroad. As a new type of environmentally friendly travel mean, low-carbon tourism becomes the future strategic direction of the development of the tourism industry. Based on the related theory of low-carbon tourism, the paper, puts forward the problems existing in the development of low-carbon tourism, and puts forward some suggestions on its development.

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