Experimental Study on the Effect of Advancing Speed and Stoping Time on the Energy Release of Overburden in an Upward Mining Coal Working Face with a Hard Roof

Cui, Feng; Yang, Yanbin; Lai, Xingping; Jia, Chong; Shan, Pengfei

doi:10.3390/su12010037

Cited by 18 publications

(15 citation statements)

References 12 publications

(13 reference statements)

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“…The data in this time period was representative and could support the results of the experiment. According to microseismic 42‐46 data recorded in a laboratory, there was one significant microseismic event energy peak during simulated mining corresponding to the fracture of primary key layer.…”

Section: Discussionmentioning

confidence: 99%

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

Xiao

Han

Shuang

et al. 2021

Energy Science & Engineering

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To prevent outbursts and extract the gas, it is necessary to investigate the structure of the key layer and the evolution of cracks during coal mining over a large height. A physical similarity model with a geometric similarity ratio of 1:100 and a strike length of 2 m was established on the basis of prevailing geological and mining conditions. Stress sensors and microseismic equipment were adopted to monitor the collapse characteristics of different key layers through variations in stress and energy. The research results showed that: The displacement of the overlying strata exhibited group motion characteristics marked by the key layer and there was zone of rapidly increasing stress in the goaf behind the working face before and after the fracture of the key layer. Through the analysis of microseismic events, fissure density, and fractal dimension, we found that: before and after the primary key layer fractured, the energy loss in the microseismic event accounted for 27% of the total, the fissure density also changed abruptly from 8 cracks/m to 10 cracks/m and the slope of the fractal dimension curves changed from 0.00243 to 9.94801 × 10−4. Then a gas drainage model suitable for this condition was constructed. When the primary key layer had not fractured, the cracks below fully developed to form a gas migration channel and a gas enrichment area, and gas boreholes could be arranged therein. After the primary key layer had been fractured, the rate of crack development decreased, the permeability would increase, and the gas concentration would increase. The boreholes could still be arranged in the gas migration channel. This study elucidated the control role of the primary key layer from multiple angles and provided experimental guidance for gas drainage over large‐mining heights and during complex key layer mining.

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Section: Discussionmentioning

confidence: 99%

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

Xiao

Han

Shuang

et al. 2021

Energy Science & Engineering

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“…The water solution mining method is used for the excavation of both the UGS and SPR salt caverns. According to available standards [48], [49], the design life of the underground energy storage salt caverns is at least 30 years, which is used in the calculations. During the operating time, synchronized injection-withdraw patterns are recommended because instability influence may occur in pillars if asynchronous injection-withdraw patterns are adopted [29].…”

Section: B Conditions For Tightness Analysismentioning

confidence: 99%

Tightness Analysis of Underground Natural Gas and Oil Storage Caverns With Limit Pillar Widths in Bedded Rock Salt

et al. 2020

Self Cite

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To fully utilize the abandoned salt cavern resources and to increase the total amount of the fossil energy reserve of China, reconstructing some of these salt caverns for underground gas storage (UGS) or strategic petroleum reserve (SPR) would be an effective method. The salt resources in China mainly are bedded salt, which brings great challenges for the cavern construction and safety evaluation. In this paper, the investigations are presented to evaluate the tightness of the UGS and SPR salt cavern facilities, located in the bedded rock of Jintan, China. Microcosmic analysis, and permeability and porosity tests of the surrounding rock are carried out to determine their properties, which provide the basic data for the tightness assessment. A 3-D numerical model is developed based on the test results and the geological features of the target formation. The numerical simulation results show that the seepage velocity, seepage range and loss rate of leakage of the SPR salt caverns are much smaller than those of UGS salt caverns. The cavern's pillar width with a pillar to diameter ratio (P/D) of 1.5 can satisfy the tightness requirement of SPR salt caverns, but it cannot meet the requirement of UGS caverns. This indicates that some existing abandoned salt caverns in Jintan which are unsuitable for UGS due to their small pillar width have the potential to be rebuilt for SPR. This would help to increase the storage capacity of crude oil in China. The results can also provide a reference for the implementation of similar projects in other bedded salt districts. INDEX TERMS Bedded rock salt, underground gas storage, strategic petroleum reserve, tightness, seepage.

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“…The theoretical and practical research on coal pillar dynamic disasters has strongly supported the safe and e cient mining, but little relevant research has been conducted on layout methods for goaf-side roadways of mining faces with overlength at deep and large mining heights. The authors have been committed to researching dynamic disasters for a long time [30][31] and have fully drawn on previous research experiences and achievements. Focusing on the working faces with an overlength at deep and large mining heights at No.2 Coal Mine of Huangling Mining (Group) in Shaanxi Province, the authors have researched the "dynamic-static" load evolution rules for coal pillars, and ultimately determined the layout method for goaf-side roadways, thus providing a scienti c basis of safe, e cient and sustainable mining in the stopswith large mining heights at deep.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Evolution Law and Width Determination of Section Coal Pillars in Deep Mining Height Working Face

Zhaoyuan¹,

Cui²,

Liu³

et al. 2021

Preprint

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The coal column undergoes three types of force evolution from the formation to the end of mining. This paper takes large mining height working face at No.2 Coal Mine as example to study the ways to avoid dynamic instability of the coal column triggered by the deep mining. By means of geological survey, theoretical analysis, numerical calculation and field verification, the load processes under the three stress stage are proposed, and the evolution law of the coal column is analyzed. The study shows that the depth, large mining height working face, coal pillar force and size altogether determine the damage characteristics of the coal pillar. With the combination of Flac3D and 3DEC, it can be analyzed that the plastic failure and displacement characteristics of the 35m coal column under the action of secondary dynamic load coincide. The perturbation stress distribution is stable, which finally determines the reasonable width of the 35m coal column. Field measurements show that the top and gang of the 35m coal column undergo three kinds of displacement characteristics. The lower part is more stable. The top plate of the upper and lower corner completely collapsed in the emptying area, which can play a good supporting role.

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Experimental Study on the Effect of Advancing Speed and Stoping Time on the Energy Release of Overburden in an Upward Mining Coal Working Face with a Hard Roof

Cited by 18 publications

References 12 publications

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

Tightness Analysis of Underground Natural Gas and Oil Storage Caverns With Limit Pillar Widths in Bedded Rock Salt

Dynamic Evolution Law and Width Determination of Section Coal Pillars in Deep Mining Height Working Face

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