Abstract Discrete element calculations of the top-coal drawing process for different gangue-coal density ratios were conducted to investigate effect ratio on mechanism in longwall caving. The effects analyzed body, boundary, and recovery top coal. results show that increasing ratio, initial body goaf side is farther away from support its width volume gradually increase. upper part sickle-shaped...

The paper presents results of application of a machine learning method, namely the induction of classification and regression rules, for seismic hazard prediction in coal mines. The main aim of this research was to verify if machine learning methods would be able to predict seismic hazard more accurately than methods routinely used in Polish coal mines on the basis of data gathered by monitorin...

Based on the field conditions of Huojitu Coal Mine Shendong coal in Northern China, eight dynamic numerical models are developed to examine interaction between shield and surrounding rock longwall panel. The take into consideration actual mining process simulate change working resistance for same shallow burial but with different height conditions, ranging from 2.5 7 m. results show that averag...

The paper describes a case study of the safety hydraulic system damage in working longwall Polish coal mine. elements are component powered roof supports which secure shield against during rock burst incidents. event, occurred mining process, caused uncontrolled lowering support height process. may cause danger loss stability along form and collapses represent serious immediate to health employ...

Longwall shearers’ haulage system of the Eicotrack type, used most often nowadays, is presented in this article. Its disadvantages, causing problems with a correct operation mechanized longwall shearer systems, are discussed. The concept innovative Flextrack, which should reduce occurrence disadvantages mentioned above, described. A course and research results, connected rig tests Flextrack fun...

Purpose. On the basis of analysis and assessment geological conditions, technological parameters support methods a longwall, author has pointed out causes rules phenomenon face spall roof falling in fully mechanized longwall. From there, proposes some solutions to prevent this ensure safety Methods. The statistical, survey actual field data are used achieve research results. Findings. results a...

Large deformations that accompany longwall mining result in complex spatial and temporal distributions of changes in undrained pore ̄uid pressures around the advancing face. These seemingly anomalous changes are recorded in the rapid water level response of undermined and adjacent wells, and may be explained in the short-term as a undrained poroelastic e€ect. A three-dimensional ®nite element mo...

Barometric pressure changes affect air density, leading to change in the mass of the gas in the gob. When the barometric pressure decreases, the volume of gas in the gob expands, while the volume of gas contracts when the barometric pressure increases, causing the gob to breathe out and in. Although the concept of gob “breathing” is simple, its effect on spontaneous heating of coal in the gob a...