China has considerable coal resources. Benefiting from the widespread distribution of coal measures and the inter-sedimentary development of coal bed, dark shale, and fine-grained tight sandstone in coal measures, China has a geological environment and material basis favorable for the co-occurrence of a variety of coal gases. With such a huge reservoir of coal gases, including gases such as coa...

Spontaneous combustion of subsurface coal is an extremely complicated chemical and physical changing process. In order to quantitatively understand the development of underground coal fires, the heat transfer processes coupled with multi-stage oxidation of coal are investigated by experimental and numerical methods in this paper. With controlled temperature and under lean oxygen conditions, the...

Abundant steeply-dipping thick coal seams (SDTCS) have been found in Xinjiang, China, and they are mined largely by the horizontal section top-coal caving (HSTCC) method. The hanging wall of the HSTCC face is nearly vertical and does not fracture easily after the underlying coal is extracted. As a result, stress tends to concentrate in the hanging wall of the lower-section working face (LSWF) a...

Water and gas samples were collected from (1) nine shallow groundwater aquifers overlying Marcellus Shale in north-central West Virginia before active shale gas drilling, (2) wells producing gas from Upper Devonian sands and Middle Devonian Marcellus Shale in southwestern Pennsylvania, (3) coal-mine water discharges in southwestern Pennsylvania, and (4) streams in southwestern Pennsylvania and ...

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...

Organic Compounds Associated with Hydraulic Fracturing: Groundwater Composition and Natural Attenuation Potential by Brian D. Drollette Department of Civil and Environmental Engineering Duke University Date:_______________________ Approved: ___________________________ Desiree Plata, Supervisor ___________________________ Lee Ferguson ___________________________ Avner Vengosh An abstract of a th...

The shearing of natural fractures is important in the permeability enhancement of shale gas reservoirs during hydraulic fracturing treatment. In this work, the shearing mechanisms of natural fractures are analyzed using a newly proposed numerical model based on the displacement discontinuities method. The fluid-rock coupling system of the model is carefully designed to calculate the shearing of...

Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment where acoustic emission monitoring was used to investigate rock damage in a high-alpine rockwall in...

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...