There is a great risk of roof falls in the advance support section mining face (ASSoMF), and it difficult to control roof. Based on soft Lijiahao coal mine, this paper studies stress distribution ASSoMF space-time evolution surrounding rock plastic zone by using theoretical analysis numerical simulation, reveals its failure mechanism. effect resistance zone, proposed that should mainly adapt ro...

In this study, the roof-cutting-type gob-side entry retaining is introduced, and its application in medium-thickness coal seams studied. Based on analysis of construction procedure principle, mechanical model retained roadway structure cantilever beam formed by roof cutting was established, support resistance deformation were obtained. addition, through technological design numerical simulation...

The U.S. National Institute for Occupational Safety and Health (NIOSH) conducted a study to determine the effectiveness of a filtered air delivery system to reduce respirable dust exposure of roof bolter operators in underground coal mines. When performing roof bolting operations, roof bolter operators may experience exposure to high levels of respirable dust during a working shift, especially ...

Youth gangs are on the rise. Today they threaten virtually every major city, many small communities, and even rural areas. The Office of Juvenile Justice and Delinquency Prevention (OJJDP) is committed to helping communities overcome this problem, and an essential first step is understanding the factors that contribute to the growth of youth gangs and the relationship of gang membership to deli...

Gob-side entry retaining by roof cutting, a pillarless mining technique, plays critical role in maintaining continuous production, rapid connection, and enhancing the coal recovery rate fully mechanized top caving working faces. This technique stands as sustainable development method mining. The present research, set against backdrop of Yitang Coal Mine 100602 gob-side investigates influence ro...

In view of the occurrence conditions inclined coalbed, deformation and failure characteristics main roof will affect safe production working face. Therefore, study in coalbed has guiding significance for control surrounding rock. This paper takes II1042 face Taoyuan Coal Mine as research background, adopts methods theoretical analysis, numerical calculation, field practice to analyze evolutiona...

The control difficulty of whole coal cavern groups is greatly increased due to the characteristics soft rock with low strength, large sections, and mutual influence crossed groups. section gas storage group taken as research background. In this paper, equivalent circle method used solve loose a rectangular roadway, numerical calculation obtain deformation stress distribution laws surrounding un...

The nearby goaf road in the extra-thick coal seam of Datong mining area exhibits intense strata pressure behavior, which affects working face mining. Herein, we study laws behavior this detail using various methods, including laboratory tests, theoretical analyses, numerical simulation, and field monitoring. Considering mine characteristics road, namely, roof cracking, two-side deformation, flo...

Abstract Directional fracturing is fundamental to weakening the hard roof in mine. However, due significant stress disturbance mine, principal stresses present complicated and unmeasurable. Consequently, designed hydraulic fracture (HF) extension path always oblique stresses. Then, HF will deflecting propagation, which restrict weakness of roof. In this work, we proposed an approach drive propa...