Roof Deformation Characteristics and Preventive Techniques Using a Novel Non-Pillar Mining Method of Gob-Side Entry Retaining by Roof Cutting

Wang, Yajun; Gao, Yubing; Wang, Eryu; He, Manchao; Yang, Jun

doi:10.3390/en11030627

Cited by 85 publications

(62 citation statements)

References 16 publications

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“…The gob was filled with solid wastes, such as gangues and fly ash, which greatly reduced the roof subsidence and the pressure on roadside support. Fourth, the technique of no‐pillar mining with automatically formed gob‐side entry retaining was proposed . This technique presplit the roof along the gob‐side via borehole blasting, and the gob‐side roof was cut down to the gob as the working face advancing.…”

Section: Introductionmentioning

confidence: 99%

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Fan

Liu

Tan

et al. 2019

Energy Science & Engineering

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Due to the complex geostress and mining conditions in the coal seam with depth of 800 m, stability of surrounding rock for gob‐side entry retaining is very difficult to achieve. In this paper, we firstly propose an innovative bolt‐grouting controlled roof‐cutting for gob‐side entry retaining (BCR‐GER) approach for deep coal mines. Secondly, a mechanical model of “surrounding rock‐supporting body” for BCR‐GER is constructed, which consists of coal wall, roadside props, and gangues in gob (the whole supporting body). Thirdly, the key parameters (ie, cutting height, cutting angle, grouting cable length, and row of roadside props) are designed. Finally, field practice was applied at the No. 31120 haulage roadway of the Suncun coal mine in China, and in situ investigations were conducted for verification. Field measurement results show that maximum convergences of roof‐to‐floor and side‐to‐side were 264 mm and 113 mm, respectively. What is more, the maximum support resistance of roadside props was reduced by approximately 58%. The deformation and failure of surrounding rock were effectively controlled, and the pressure on roadside props was greatly reduced. This research fully considers the bearing properties of gangues in gob, eliminates the secondary disasters caused by borehole blasting, and provides guidance and reference for deep surrounding rock control of the same or similar gob‐side entry.

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Section: Introductionmentioning

confidence: 99%

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Fan

Liu

Tan

et al. 2019

Energy Science & Engineering

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“…The technologies of hydraulic fracturing to weaken hard roofs in advance have been gradually accepted in coal mines of China recently [54][55][56]. In mining engineering, there are two requirements for the application of the proposed mining-induced failure criteria: (1) There is a soft layer being sandwiched between the two interactional hard roof structures; (2) the equilibrium condition of structures should satisfy Equations (6), (13), and (14). Further, correlative parameters of IHRS need to be re-determined considering the varying geological conditions.…”

Section: Discussionmentioning

confidence: 99%

“…With the development of clean utilization technologies, coal will always provide energy sources for the social development [1]. To ensure the efficient operation of coal production systems, security maintenance of entries in underground mining is extremely important, including large deformation control, rock burst forecast, and other early warnings of dynamic disaster [2][3][4]. As the development of the longwall mining, many entries are arranged along the side of a gob with a protection of coal pillar or artificial wall, so as to cope with the mining-induced movement of the hard roof structures [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Mining-Induced Failure Criteria of Interactional Hard Roof Structures: A Case Study

et al. 2019

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Due to the additional abutment stress, interactional hard roof structures (IHRS) affect the normal operation of the coal production system in underground mining. The movement of IHRS may result in security problems, such as the failure of supporting body, large deformation, and even roof caving for nearby openings. According to the physical configuration and loading conditions of IHRS in a simple two-dimensional physical model under the plane stress condition, mining-induced failure criteria were proposed and validated by the mechanical behavior of IHRS in a mechanical analysis model. The results indicate that IHRS, consisting of three interactional parts-the lower key structure, the middle soft interlayer, and the upper key structure-are governed by the additional abutment stress induced by the longwall mining working face. The fracture of the upper key structure in IHRS can be explained as follows: Due to the crushing failure, lower key structure, and middle soft interlayer yield, the action force between the upper and lower key structures vanishes, resulting in fracture of the upper key structure in IHRS. In a field case, when additional abutment stress reaches 7.37 MPa, the energy of 2.35 × 10 5 J is generated by the fracture of the upper key structure in IHRS. Under the same geological and engineering conditions, the energy generated by IHRS is much larger than that generated by a single hard roof. The mining-induced failure criteria are successfully applied in a field case. The in-situ mechanical behavior of the openings nearby IHRS under the mining abutment stress can be clearly explained by the proposed criteria.

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“…However, the retained coal pillars have a low recovery rate and some cannot be recycled, resulting in significant resource loss. This loss can reach 40% of the mine's recoverable reserves and is the root cause of coal mining losses . After years of research and exploration, by using the theory of “roof cutting shortwall beam”, Academician Manchao proposed the innovative technology of gob‐side entry retaining formed by roof cutting and pressure releasing .…”

Section: Introductionmentioning

confidence: 99%

Evolution and application of airflow permeability characteristics of gob in roof cutting and pressure releasing mining method

Chen

Wang

et al. 2020

Energy Science & Engineering

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Cutting roof and release pressure technology has changed the pressure transmission mode of the roof and the caving characteristics of roof rock, which in turn has changed the permeability evolution of the gob. To obtain the permeability characteristics of the gob for the roof cutting and pressure releasing mining method, a mathematical model for the gob voidage and permeability was established by analyzing the overlying strata movement law and the lateral stress variation in the gob. The airflow migration law of haulage roadway 12 201 in Halagou coal mine was studied using Fluent software and an established mathematical model. The main conclusions obtained are as follows: The overburden pressure and lateral stress in the gob gradually increase with the advancement of the working face; along the direction of the retaining roadway, there are two roadway windflows entering the critical zones (the 22-100 m and 390-398 m sections). The inflow at these two sections accounted for 59% of the total air inflow, of which the most critical is the 28-53 m section, which accounts for 43% of the total air inflow in the two severe air leakage sections. The findings of this work provide a theoretical basis for the implementation of antileakage technology in the gob under the roof cutting and pressure releasing mining method and help reduce the risk of spontaneous combustion in the gob. K E Y W O R D Scaving characteristics of roof rock, cutting roof and release pressure, gob, voidage and permeability model 2074 |

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Roof Deformation Characteristics and Preventive Techniques Using a Novel Non-Pillar Mining Method of Gob-Side Entry Retaining by Roof Cutting

Cited by 85 publications

References 16 publications

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Mining-Induced Failure Criteria of Interactional Hard Roof Structures: A Case Study

Evolution and application of airflow permeability characteristics of gob in roof cutting and pressure releasing mining method

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