Introduction: The Glanerbrug ordinary chondrite fell April 7, 1990 through the roof of a house in the Netherlands [1,2]. The inhomogeneous character of the rock was recognized immediately [1] and Glanerbrug was officially classified as an LL breccia [3]. In later publications Glanerbrug was described as an L/LL5 chondrite (e.g., [4]). Based on the somewhat unclear and inconsistent classificatio...

The focus of this paper is the thick soft rock mass roof track roadway in No. 3606 panel Chaili Coal Mine. Due to its substantial thickness, susceptible damage and deformation during mining process. In order preserve integrity roof, a full anchor cable support scheme proposed after studying mechanism bolt-anchor support. supporting parameters feasibility were determined through experience numer...

Original scientific paper With the increase in mining depths and the occurrence of worsening conditions, deep, large-scale and rapid mining may lead to more complicated dynamic features for tunnels, making them vulnerable to dynamic disasters such as rock bursts and coal/gas outbursts with subsequent heavy damage and casualties. A three-dimensional structural mechanics model for deep stopes was...

Longwall mining is the only technically proven and established method worldwide for coal extraction at greater depth. In this paper, 2D plane strain finite element models of longwall panels are developed and analyzed to understand the interaction of hydraulic powered support with surrounding rock strata. Based on Indian geomining conditions, finite element models are developed including the str...

The ability to understand stress redistribution within a mine will allow for greater extraction efficiency with reduced safety concerns. Stress redistribution has been examined at the laboratory scale using ultrasonic tomography and numerical modelling using PFC. In the first part of the study an equation is developed to convert the macro-properties of the rock to the micro-properties of the pa...

Both the deformation characters and the failure mode of the large cross-sectional longwall installation roadway under compound roof are becoming an emergent issue than ever before due to the rapid development of modern mining equipment. Various engineering applications have revealed that the insufficient design and inappropriate support technology are the main reasons for the fatal accidents as...

This article introduces a new non-pillar coal mining technology (i.e., Gob-side Entry Retaining by Roof Cutting (GERRC)) under the condition of thick and hard roofs. First, we theoretically analyzed solution to large suspension span roof in mining. Three-Zone pre-split blasting design for roofs was proposed, based on principles rock mechanics. After field experiments, successfully applied huge ...

Three-dimensional stability of roofs in deep flat-ceiling cavities is analyzed. The number, factor safety, and required supporting stress are used as measures roof stability. Despite the simplicity flat geometry, three-dimensional analysis presents some complexities owed to shape failure surface geometry collapse mechanism. mode assumes a rock block moving downward into cavity, study aims recog...

The Tashan coal mine is selected as a case study to determine the deformation and damage mechanisms of lower roadway in close-range residual pillar area. Roof drilling peephole technology applied detect roof surrounding rock. A boundary invisibility equation derived for plastic zone circular hole based on theory butterfly non-uniform stress field which principal occurs at an arbitrary angle ver...