Study on mechanism and improvement technology of Top coal loss in horizontal sublevel fully mechanized caving mining

Wu, Fengfeng; Zhang, Shurong; Yue, Xin; Liu, Qiwen; Zhang, Jian; Lv, Bo; Gao, Zhiqiang

doi:10.1177/01445987221092850

Cited by 4 publications

(4 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The roof's surrounding rock is shattered, and the damaged main roof can be considered a block construction. The gangue in the lower coal seam's goaf is classified as a granular structure (Kong et al 2021; Zhang and Wang 2021; Li et al 2022a,b; Wang et al 2022; Wu et al 2022). According to the structural characteristics of the roof strata under the close distance coal seams, it can be abstracted as a “loose-block-loose” structural model, as shown in Figure 3:…”

Section: Fracture Characteristics Of Lower Coal Seam Roofmentioning

confidence: 99%

Roof breaking characteristics and mining pressure APPEARANCE laws in close distance COAL seams

Liu

Ren

et al. 2022

Energy Exploration & Exploitation

View full text Add to dashboard Cite

In order to obtain lower coal seam mining of roof breaking characteristic and the law of mine pressure appearance in the close distance coal seams, this paper takes working face 6101 of a mine as the engineering background, and studies the roof breaking characteristics and pressure law in close distance coal seam through theoretical analysis, numerical simulation and engineering verification, which provides the basis for roof control in lower coal seam mining. The results show that the maximum failure depth of 4# coal seam mining on floor is 8.28 m. The lower coal seam mining roof forms a “loose-block” structure, and the main roof fracture step distance is 44.61 m. The UDEC simulation shows that the initial weighting intensity of 6# coal seam is large, and the first weighting distance step is about 40 m. The hydraulic support with the highest working resistance should be chosen based on the roof pressure analysis, and the weighting is frequent. The hydraulic support with higher working resistance should be selected through the analysis of roof pressure, some control measures should be taken to strengthen the organization and management, and prevent the occurrence of roof disasters. The roof is effectively controlled through engineering verification. The study further recognizes the laws of mining pressure appearance in lower coal seam of close distance coal seam, and provides experience for similar mine mining.

show abstract

Section: Fracture Characteristics Of Lower Coal Seam Roofmentioning

confidence: 99%

Roof breaking characteristics and mining pressure APPEARANCE laws in close distance COAL seams

Liu

Ren

et al. 2022

Energy Exploration & Exploitation

View full text Add to dashboard Cite

show abstract

“…The longwall top coal caving mining technology (LTCC) has demonstrated its high efficacy as a mining method, offering robust support for addressing the challenges of coal extraction in complex conditions characterized by significant variations in thickness, one-time full-height extraction, intricate roof slab structures, and horizontally segmented sharply inclined coal seams [1][2][3][4]. In comparison to other methods, such as large-height mining and stratified mining, LTCC presents numerous advantages, including low investment requirements, rapid production rates, cost-effectiveness, energy efficiency, minimal emissions, and exceptional adaptability [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Characteristics and Control Method of Coal Leakage between Supports in Integrated Mining of Extremely Loose and Soft Coal Seams

Yang,

Zhang,

Wang

2024

Energies

Self Cite

View full text Add to dashboard Cite

Extremely loose and soft coal seams, with a Platts coefficient of less than 0.3, are easy to break in the process of integrated mechanized roof coal mining and are prone to spilling and piling up between the hydraulic supports, which is a safety hazard for the movement of equipment. The coal particles must be cleaned up manually, resulting in reduced resource recovery rates and lower mining face efficiency. To effectively mitigate and control the problem of coal spillage accumulation amidst hydraulic supports, this study utilizes discrete element numerical simulation to examine the characteristics of block size distribution and the spilling process during the crushing of highly loose and soft top coal. By taking into account various parameters associated with shelf spacing, this research identifies key factors for controlling arching and self-stopping phenomena in top coal particles. The study findings suggest that the uppermost coal layer undergoes significant fragmentation during the integrated mining process of loosely packed and soft coal seams, resulting in a higher probability of coal leakage issues observed near the rack’s coal wall side and at the end of the roof control area. The key factors contributing to the self-arresting of spilled coal particles include inherent characteristics of the coal body, particle diameter, and stand spacing. In this specific mine under investigation, an arch formation naturally occurs to prevent further leakage when the distance between stands is less than eight times the diameter of particles, and after process correction, the average time saving for a single shift of manual floating coal cleaning at the working face is about 2 h, and the proportion of time saving is more than 50~75%.

show abstract

“…With the gradual expansion of deep mining for coal resources in China, coal and gas outbursts in mines have become more and more serious. To ensure safe production in mines, it is extremely important to arrange the bottom pumping roadway on the floor of the working face for gas drainage from the upper working face [1][2][3][4][5]. However, when the working face is being mined back, the bottom plate is affected by the mining of the working face, and the stress is transferred to the deep part of the bottom plate of the working face of the roadway, which redistributes the stress in the rock surrounding the bottom plate.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Perimeter Rock Damage in a Bottom-Pumping Roadway under the Influence of Mining Activities and Rational Location Studies: A Case Study

Bai,

Wu,

Yang

et al. 2024

Applied Sciences

Self Cite

View full text Add to dashboard Cite

With the aim of determining the damage characteristics and a reasonable positional arrangement of the surrounding rock in a bottom-pumping roadway influenced by mining in a high-gas mine, the boundary equation for the plastic zone of the surrounding rock in a circular roadway under an unequal compressive stress field was adopted to analyze the relationship between the distribution characteristics of the plastic zone of the bottom-pumping roadway and the stability of the rock surrounding the bottom-pumping roadway under different bidirectional stress ratios. This was carried out in the bottom-pumping roadway of the working face of Licun coal mine 3301 as the engineering background, where the nature of the coal seams mined is bituminous coal, and the absolute gas outflow is 0.5 m3/min−1. A numerical simulation was used to analyze the distribution characteristics of the surrounding rock stress and the bidirectional stress ratio, as well as the deformation and damage characteristics of the surrounding rock at different positions in the bottom-pumping roadway. A numerical simulation was applied to analyze the distribution characteristics of the surrounding rock stress and the two-way stress ratio, as well as the deformation and damage characteristics of the rock surrounding the bottom-pumping roadway when the bottom-pumping roadway was arranged in different locations. The results show that, with an increase in the bidirectional stress ratio, the plastic zone of the perimeter rock in the bottom-pumping roadway shows nonuniform “butterfly” distribution characteristics, which seriously affects the stability of the rock on the perimeter of the roadway; the stress on the bottom plate of the working face after excavation can be divided into four areas according to the size of the bidirectional stress ratio and the stress loading and unloading states. In addition, the size of the perimeter rock deformation can be sorted into four areas according to the damage range of the perimeter of the rock plastic zone in the bottom-pumping roadway. The size of the deformation in the surrounding rock can be sorted as follows: unpressurized high-stress ratio > unpressurized stress ratio stable area > pressurized low-stress ratio area > original rock stress ratio area. Accordingly, we found that the reasonable location of the bottom-pumping roadway is arranged at the 15 m position outside the hollow area below the coal pillar, along the limestone upper medium-grained sandstone layer along the bottom. The study’s results were applied to the field. The industrial experiments on the site show that the deformation of the surrounding rock is reasonable when the bottom-pumping roadway is dug along the limestone roof and arranged 15 m outside the fault of the mining hollow area below the coal pillar.

show abstract

Study on mechanism and improvement technology of Top coal loss in horizontal sublevel fully mechanized caving mining

Cited by 4 publications

References 5 publications

Roof breaking characteristics and mining pressure APPEARANCE laws in close distance COAL seams

Roof breaking characteristics and mining pressure APPEARANCE laws in close distance COAL seams

Numerical Study on the Characteristics and Control Method of Coal Leakage between Supports in Integrated Mining of Extremely Loose and Soft Coal Seams

Characteristics of Perimeter Rock Damage in a Bottom-Pumping Roadway under the Influence of Mining Activities and Rational Location Studies: A Case Study

Contact Info

Product

Resources

About