.... In this study, we evaluated the effects of different shapes and distribution densities of mineral grains in coal on failure mechanics using the numerical software 3DEC. The main aim of this study was to identify possible failure mechanisms influenced by mineral habit and frequency in coal. Exploring differences...

... ABSTRACT: Coal bursts are violent dynamic failures that occur in underground coal mines and can injure workers and disrupt mining operations. The coal bursting phenomenon is complex and many factors contribute to a mine's propensity to experience bursting. Among these is the presence of thick...

...-mechanical coal deformations. Limited efforts have been devoted towards the understanding of thermo-mechanical deformations in the coalbed methane (CBM) industry. This study proposed a theoretical model of thermal expansion coefficients through energy principle. Direct measurements of coal deformations...

... ABSTRACT: Underground coal pyrolysis (UCP) represents an environmentally friendly approach to exploiting coal resources through in-situ conversion, with its efficacy hinging on the efficient flow of gas through porous media. Consequently, the study of flow behavior, particularly permeability...

... ABSTRACT: Rock layering is pervasive in the Shanxi formation of Ordos Basin. In this area, coal, shale and limestone rock are developed vertically and alternatively and high heterogeneity between layers has a great effect on the fracture propagation. In this study, the true tri-axial...

... ABSTRACT: Despite many years of research, rock bursts and excessive gas emissions remain a longstanding cause for concern and a major hazard in underground coal mining. There are several traditional approaches to forecast rock bursts in underground mining, but it is difficult to use a single...

... ABSTRACT: In order to investigate the stress distribution characteristics and deformation failure law of micro-coal structure under loading, a digital model that can characterize the true pore structure of coal and rock mass is constructed by combining computed tomography (CT) scanning and 3D...

... ABSTRACT: Fracturing using liquid nitrogen (LN 2 ) has been successfully applied in coalbed methane reservoirs stimulation in field since the 1990s. However, the mechanism of LN 2 acting on the alteration of pore structure is still obscure. For moisture coal, the cryogenic treatment can...

... ABSTRACT: Nanoscale coal deformation will affect geomechanics response of coal with gas injection coupled with the external stress condition. In this study, u small-angle neutron scattering (SANS) is used to characterize the nanopore structure evolution of San Juan coal under hydrostatic gas...

... ABSTRACT: In crushed coal seams, artificial fractures cannot effectively extend during hydraulic fracturing. In this paper, a method of temporarily enhancing the mechanical properties of crushed coal seams by freezing is proposed, which can make the hydraulic fracture extend significantly...

... ABSTRACT: One of the major challenges facing longwall top coal caving (LTCC) panels is the inadequate fragmentation of hard top coal during the caving process. Following this, the effect of laoding rate on the tensile strength of coals was studied aiming to clarify the mechanism of tensile...

... ABSTRACT: Fully understand the microstructures and the rock mechanical property are extremely important for the coal seam characterization, explorations, coal bed methane (CBM), enhanced coal bed methane (ECBM), and CO2 storage. However, how the different coal rank relate...

... Juan coals under two boundary conditions, uniaxial strain and constant triaxial effective stress, where stresses and strain in vertical and horizontal directions were monitored with continued depletion. The experimental results were used to model the Biot's coefficient in vertical and horizontal...

... ABSTRACT: In this study, the water absorbability and acoustic characteristics of coal were measured at downhole temperature and pressure, considering the effects of different kinds of drilling fluids. The inversion was conducted based on these data and revealed the change of internal...

... ABSTRACT: Coal and gas outbursts have long posed a serious risk to safe and efficient production in coal mines. It is recognised that the coal and gas outbursts are triggered by excavation unloading followed by gas-driven rapid propagation of a system of pre-existing or mining-induced...

... ABSTRACT: One of the major challenges facing coal mines in Malawi is occurrence of hanging roof falls during the rainy season. Following this, the effect of humidity on the tensile strength of coal bearing rocks, arkose sandstone and fine-grained sandstone from Mchenga underground coal mine...

... ABSTRACT: Mining-induced microseismicity has been extensively used to evaluate the potential for rock bursts and coal and gas outbursts in underground coal mines. In a research project completed a few years ago, it was observed that characteristics of microseismicity around a longwall working...

... ABSTRACT: To better understand the liquid nitrogen freezing effect on different rocks, shale, coal, sandstone and carbonate were chosen to investigate the pore structure and mechanical properties damage before and after liquid nitrogen freezing. Experimental study shows that an increase...

... ABSTRACT: By using the characteristic of carbon dioxide phase transition of soft rock blasting, high pressure gas can be used. The mechanism of high pressure gas dynamic crushed rock is different of blasting and static rock breaking. Taking a coal mine as an example, according to similarity...

... ABSTRACT: Rib falls are serious safety hazards in underground coal mines. Studies of injuries and fatalities caused by rib falls have shown that the significant mining conditions that contribute to rib falls are mining height, depth of cover, and stress resulting from mining of multiple seams...