Study on Pressure Relief Technology of High-Pressure Water Jet of Residual Coal Pillar in Overlying Goaf in Close Seam Mining

Yang, Shuai; Li, Xuehui; Wang, Jun; Shen, Zhen; Xu, Guangzheng

doi:10.1155/2022/7842921

Cited by 5 publications

(5 citation statements)

References 17 publications

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“…On the basis of the difficulties in roadway support and support principles, [23][24][25][26][27][28][29] in view of the large area roof fall disaster of the broken surrounding rock of No. 11103 fully mechanized caving roadway under the double gob, the Usteel + anchor + prop coupling support structure is used to bear the broken surrounding rock, resist the top pressure, and prevent the U-shaped steel from appearing weak section under the eccentric load conditions of coal pillar stress concentration and gob stress reduction, which reduces the bearing capacity.…”

Section: Analysis Of Coupling Support Structurementioning

confidence: 99%

Coupling support technique for coal roadway under double gobs in close coal seams

Wu,

Nan,

Chen

et al. 2024

Energy Science & Engineering

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In the process of lower coal roadway support under double gobs in close coal seams, there are problems such as the whole destruction of the lower coal seam and the intermediate strata, the thin roof of the lower coal roadway with the smaller support space, the upper rock of the lower coal roadway without anchor bearing layer, the roof falling, the anchor cable offing, and so on. On the basis of the engineering background of No. 11103 haulage roadway in Fenxi coal mine, the research methods of theoretical modeling analysis, numerical simulation analysis and field engineering test are comprehensively adopted. In this paper, the layout of the roadway with floor insertion in the lower coal seam, the distribution characteristics of surrounding rock deviatoric stress, the control principle of broken surrounding rock and the coupling support method of shed–cable–prop are systematically studied. The study shows that many measures are needed to ensure the stability of the surrounding rock in the strong mining roadway of the lower coal seam. The lower coal seam roadway section was modified from the original rectangular section to adopt an arched section to counteract the broken roof. The staggered position of the lower coal seam roadway layout was modified from the original coal roadway position to a coal–rock roadway, so as to avoid the area of high deviatoric stress in the coal pillar and the area of crushed coal body, and to leave an effective support space for the roof. The support scheme of the lower coal seam roadway was improved to use anchor cable and single prop to support the weak section of U‐type steel shed with local coupling, and realize unequal force coupling by adjusting the size of the force at different coupling points. In the field monitoring the deformation of the roadway is small, and the support effect is good.

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Section: Analysis Of Coupling Support Structurementioning

confidence: 99%

Coupling support technique for coal roadway under double gobs in close coal seams

Wu,

Nan,

Chen

et al. 2024

Energy Science & Engineering

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“…In actual production, for water preservation mining drainage, unsealing of the fire area with water injection into the coal mining area is conducted, and after the exploration and release of old kiln water, , the water immersion coal is more likely to spontaneously ignite. Regarding research on the spontaneous combustion characteristics of the water immersion coal, many Chinese and foreign scholars have analyzed the influence of moisture on the physical and chemical structure and spontaneous combustion characteristics of coal from different perspectives.…”

Section: Introductionmentioning

confidence: 99%

“…4 The spontaneous combustion and oxidation processes of coal are mainly manifested as changes in the functional group content, free radical concentration, and pore structure of the coal on the micro level and the changes in the thermal characteristics at the macro level. 5 In actual production, for water preservation mining drainage, 6 unsealing of the fire area with water injection into the coal mining area is conducted, 7 and after the exploration and release of old kiln water, 8,9 the water immersion coal is more likely to spontaneously ignite. Regarding research on the spontaneous combustion characteristics of the water immersion coal, many Chinese and foreign scholars have analyzed the influence of moisture on the physical and chemical structure and spontaneous combustion characteristics of coal from different perspectives.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Influence of Pore Structure and Group Evolution on Spontaneous Combustion Characteristics of Coal Samples of Different Sizes During Immersion

Guo

et al. 2023

ACS Omega

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To study the influence of water immersion on the evolution of the groups and spontaneous combustion characteristics of coal samples with different sizes, raw coal from the Fengshuigou Coal Mine operated by Pingzhuang Coal Company in Inner Mongolia was studied. The infrared structural parameters, combustion characteristic parameters, and oxidation reaction kinetics parameters of D1−D5 water immersion coal samples were tested, and the mechanism of spontaneous combustion during the oxidation of submerged crushed coal was investigated. The results were as follows. The water immersion process promoted the re-development of coal pore structure, and the micropore volume and average pore diameter were 1.87−2.58 and 1.02−1.13 times those of raw coal, respectively. The smaller the coal sample sizes, the more significant the change. At the same time, the water immersion process increased the contact point between the active group and oxygen in the coal, and the C� O, C−O, and −CH 3 /−CH 2 − groups in coal were further promoted to react with oxygen to generate −OH functional groups and improve the reactivity of coal. The characteristic temperature of water immersion coal was affected by the temperature rise rate, coal sample size, coal voidage, and other factors. Compared with the raw coal, the average activation energy of the water immersion coal with different sizes decreased by 12.4−19.7%, and the apparent activation energy of the coal sample with a size of 60−120 mesh was the lowest on the whole. In addition, the apparent activation energy in the low-temperature oxidation stage was significantly different.

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“…Considering the ongoing depletion of coal resources, the mining of SBCCS has commenced gradually in recent years [1][2][3]. Now, it has slowly entered the mining of the second or even the third main coal seam in the lower part [4,5]. With the continuous increase of mining scale, influenced by the mining layout of the upper and lower coal seams, geological structure, and other factors, the types of coal pillars left in the goaf of the upper coal seam are diverse (strike/inclined coal pillars, room-pillar coal pillars, etc.)…”

Section: Introductionmentioning

confidence: 99%

Research on Roof Weighting Mechanism of Coal Pillar Mining in Shallow Buried Closely Spaced Multi-seams

He,

Huang,

et al. 2023

Preprint

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In the process of mining the lower working face through the coal pillar (CP) in shallow-buried closely coal seams (SBCCS), noticeable roof step sinking and dynamic load effects on the support were observed. Taking the 22408 working face through the overlying concentrated CP of the Bulianta Coal Mine was selected as the research object. Used the methods of field measurement, physical simulation, and theoretical analysis to master the law of movement of the coal pillar and overlying strata while passing the CP, the structural coupling impact of the key strata structure of the interburden and coal pillar was revealed, which was the main reason for the cutting dynamic load effect during the passing of the CP of the working face. The advanced breaking mechanical model of the coupled roof structure of the "key strata structure of the interburden and the coal pillar" is established, and the main factors affecting the breakthrough distance of the advanced breaking distance are analyzed, and the mechanism of the strong weighting caused by the cutting roof of the working surface is explained at the stage of coal pillar. At the same time, it is obtained that when the width of the CP is 25m, the working face is 20m below the CP, which is the maximum bending moment point of the rock beam, indicating that the position that is prone to break under this width is about 5m of the coal pillar, which aligns with experimental data. The present study provides a theoretical guideline for the location and control of strong ground pressure during CP mining in SBCCS.

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Study on Pressure Relief Technology of High-Pressure Water Jet of Residual Coal Pillar in Overlying Goaf in Close Seam Mining

Cited by 5 publications

References 17 publications

Coupling support technique for coal roadway under double gobs in close coal seams

Coupling support technique for coal roadway under double gobs in close coal seams

Experimental Study on the Influence of Pore Structure and Group Evolution on Spontaneous Combustion Characteristics of Coal Samples of Different Sizes During Immersion

Research on Roof Weighting Mechanism of Coal Pillar Mining in Shallow Buried Closely Spaced Multi-seams

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