An innovative approach to thin coal seam mining of complex geological conditions by pressure regulation

Zhao, Tianfeng; Zhang, Zhenyu; Tan, Yunliang; Shi, Chengzhong; Wei, Ping; Li, Quan

doi:10.1016/j.ijrmms.2014.05.021

Cited by 22 publications

(8 citation statements)

References 6 publications

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“…Combining equations (3), (4), (6), and 7, then the damage variable (D) of the coal sample that includes the initial porosity (p i ) and volume strain (ε v ) under uniaxial compression condition can be expressed as follows:…”

Section: Mechanical Properties Of Bump-prone Coal With DI Erentmentioning

confidence: 99%

“…van Krevelen [4] investigated the evolution of the mechanical properties of coal with different lithotypes (organic compositions), rank (thermal maturity), and grade (mineral matter content), and the relationships between these parameters on the basis of many experiments indicated that these factors were influences directly for coal drillability, fracture stimulation, breakage, and grindability. Pattinson et al [5], and Zhao et al [6] discussed the variation of the stress field caused by geological structure with the initial fracture and permeability of coal by field monitoring and laboratory testing and reported that the fractures have a significant influence on the distribution of mining stress zones and the bearing structure of the coal mass. With the development of CT technology, the incomparable advantages in nondestructive detection of rocks and real-time detection of cracks under different conditions have become more obvious.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Bump‐Prone Coal with Different Porosities and Its Acoustic Emission‐Charge Induction Characteristics under Uniaxial Compression

Ding

Xiao

et al. 2019

Advances in Civil Engineering

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Discreteness of mechanical property affected by the intimal damage, which emerged with various degrees of material composition and geological structure, is the difference in porosity macroscopically. Although various porosities directly affect fracture activity, damage evolution and mechanical behaviour of coal bring on the bump-prone assessment error, and disaster happened “ahead of time” in deep underground energy source exploration, little research to date has focused on them. In this paper, the mechanical properties of bump-prone coal samples with different porosities were studied by uniaxial compression test and the initial damage caused by gangue and organic fracture in coal observed by CT. The result indicated that the evolution of coal strength and the logarithm of porosity were expressed by a linear negative correlation and the elastic modules decreased with the initial damage increased. A new quantitative description of damage variables is established by theoretical derivation to reflect the process of cracks formation and expiation in coal, based on volumetric strain and initial porosity. According to the Mohr–Coulomb principle, the effective stress of coal sample with higher the porosity is more likely to reach the shear strength and destruction. The amplitudes and accumulation of AE energy and charge pulse indeed vary with the stress loading stages and strength. The frequency of AE waveform is dominated in three bands (1∼50 kHz, 100∼150 kHz, and 175∼200 kHz) and that of charge induction had one frequency band 1∼100 Hz, and the amplitudes of time domain and main frequency components increased with stress improved. Both of them originated from cracks and belong to homologous signals, crack development bound to be accompanied by stress wavelet, not necessarily free charge; meanwhile, charge pulse being emerged means there must be cracks interaction and the acoustic emission signals are generated prior to charge induction.

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Section: Mechanical Properties Of Bump-prone Coal With DI Erentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Bump‐Prone Coal with Different Porosities and Its Acoustic Emission‐Charge Induction Characteristics under Uniaxial Compression

Ding

Xiao

et al. 2019

Advances in Civil Engineering

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“…Thus, it is imperative to find a reliable method for determining the working resistance in the faces of Tashan Coal Mine. Commonly, the working resistance of the support is determined by mining pressure, while the mining pressure highly depends on the broken feature and structural movement of the roof strata, which are further determined by the characteristics of the overburden strata [19]. Therefore, the interaction mechanism between hydraulic support and the roof strata should be investigated by considering the complex geological conditions of the Tashan Coal Mine.…”

Section: Introductionmentioning

confidence: 99%

Roof Strata Behavior and Support Resistance Determination for Ultra-Thick Longwall Top Coal Caving Panel: A Case Study of the Tashan Coal Mine

et al. 2018

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The Longwall Top Coal Caving (LTCC) method has greatly improved the production of ultra-thick underground coal resources. However, face fall and support closure have been becoming highly frequent accidents at the working face, and seriously threaten the safety of miners. The key to avoiding these problems is to reveal the structural evolution of the roof strata and then choose a reasonable working resistance for the hydraulic supports. According to physical modeling, theoretical analysis and field observation of the LTCC panel, four kinds of structural models can be found and defined, in consideration of the coincident movement of key strata (KS) and the mining activities of upper face in overburden strata. The KS are performed as cantilever structures, hinged structures and voussoir beam structures at three different positions in roof strata. The structural characteristics of the KS and its movement laws are shown in the four structural modes. The loads acting on the support in the four typical structural models are also analyzed. The structural instability of the broken roof strata on the upper caving panel caused by the lower ultra-thick coal seam mining is considered to be the main reason for its face's falls and support failures. Consequently, a method is proposed for calculating the working resistance of the support in the LTCC face, which is verified by the mining pressure monitoring in practice.

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“…The second geological criterion-the thickness of the seam (2)-was evaluated based on the seam thickness class. Having, in theory, four classes at the disposal, a maximum of the following points was awarded: 10 points for very thick seams (over 7 m), eight points for thick ones (from 3.5 to 7 m), five points for those of average thickness (from 1.5 to 3.5 m), and three for thin seams (less than 1.5 m) [61,62].…”

Section: Geological and Mining Areamentioning

confidence: 99%

Method for Assessing the Development of Underground Hard Coal Mines on a Regional Basis: The Concept of Measurement and Research Results

Jonek-Kowalska

2018

Energies

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The functioning and development of the extractive industry depends on many unusual conditions that are not found in other industries, such as the size of deposits, the level of natural and technical hazards, geographic location, or the method of mineral extraction (open pit or underground). Therefore, it is difficult to use universal development assessment methods for such specific production units. As a result, the research undertaken in this article aims to develop an indicator method for evaluating the development potential of underground hard coal mines. This method is based on a theoretical and practical analysis of the conditions of functioning of hard coal mines, expert research, and multiple case studies verifying the operation of the presented development indicator. The first part of the article is devoted to identifying and analyzing the criteria for assessing the functioning of underground hard coal mines. Next, the essence and methodology of creating and interpreting the proposed indicator was presented. The second part of the article is empirical, and contains the results of the assessment carried out using the developed indicators for five Polish hard coal mines for the years 2011-2015. The results of the research indicate that the most important factors in the development of hard coal mines relate to the geological and mining conditions, and those concerning natural hazard levels. However, during the functioning, the financial conditions and related production conditions, which ultimately determine the survival and development of underground mining plants, gain in significance.

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An innovative approach to thin coal seam mining of complex geological conditions by pressure regulation

Cited by 22 publications

References 6 publications

Mechanical Properties of Bump‐Prone Coal with Different Porosities and Its Acoustic Emission‐Charge Induction Characteristics under Uniaxial Compression

Mechanical Properties of Bump‐Prone Coal with Different Porosities and Its Acoustic Emission‐Charge Induction Characteristics under Uniaxial Compression

Roof Strata Behavior and Support Resistance Determination for Ultra-Thick Longwall Top Coal Caving Panel: A Case Study of the Tashan Coal Mine

Method for Assessing the Development of Underground Hard Coal Mines on a Regional Basis: The Concept of Measurement and Research Results

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