The pressure relief of coal pillars in close-distance multi-coal seam goaf is a complex engineering problem with the characteristics “dynamic mine pressure”. Hence, this paper studies such problems. First, influence factors pillar on mining face lower under condition were theoretically analyzed, and it was concluded that vertical stress most important element, followed by horizontal stress. Nex...

The study show the influence of coal mining on pillar under a repeated mining, in close seam group, fracture and instability process mechanism development oxidation pillars. In this paper, FLAC 3D numerical simulation software is used to simulate dynamic evolution characteristics stress, displacement upper pillar. results that 1) theoretical length along strike obtained by establishing mechanic...

performing a probabilistic study rather than a determinist one is a relatively easy way to quantify the uncertainty in an engineering design. due to the complexity and poor accuracy of the statistical moment methods, the monte carlo simulation (mcs) method is wildly used in an engineering design. in this work, an mcs-based reliability analysis was carried out for the stability of the chain pill...

The gob-side roadway in an isolated island working face is a typical representative of strong mining roadway, which seriously restricts the efficient and safe production underground coal mines. With engineering background main transportation 1513 (MTR 1513) Xinyi Coal Mine, this paper introduces case driving with small coal-pillar facing under alternate wide narrow faces. Through comprehensive ...

Rockburst caused by the fracture of thick hard roof and instantaneous instability residual coal pillar seriously jeopardize deep mining safety. This study takes Boertai Coal Mine, Shendong, China, as engineering background, in which dynamic mechanisms gob-side roadway surrounding rock are analyzed integrating field research, theoretical analysis, numerical simulation. The results show that over...

According to the development requirements of green mining coal resources, it is imperative improve extraction rate and application safe efficient technology. Pre-splitting roof cutting technology widely used in reducing residual pillars pressure relief mining, which has become crucial for pillar-free methods. Therefore, essential review discuss research hotspots, cutting-edge methods, principle...

Some of the most difficult coal mine roof in the United States can be found in the Illinois Basin. Factors contributing to the high roof fall rate include weak, moisture-sensitive roof rock; high horizontal stress; and limited longwall mining. The depth of cover ranges from 27 to 300 m (90 to 1,000 ft), and roof damage from horizontal stress can be severe. Moisture-sensitive roof rock, which co...