This study presents geochemical data produced from the analysis of coal and adjacent rock samples retrieved from coal mining regions in the U.S. to examine mineral matter provenance. Study sites included the North­ ern Appalachian Basin, where the units of interest were the Lower Kittanning Coal bed, the overlying Columbiana Shale, and the underlying paleosol (Allegheny Formation). Additional s...

We introduce a discrete element simulation for the hydraulic fracture process in a petroleum well which takes into account the elastic behavior of the rock and the Mohr-Coulomb fracture criterium. The rock is modeled as an array of Voronoi polygons joined by elastic beams, which are submitted to tectonical stresses and the hydrostatic pressure of the fracturing fluid. The fluid pressure is trea...

Rock dusting to prevent coal dust explosions has been in widespread use in U.S. underground coal mines since the early 1900s. Underground coal mining technology has changed significantly over this same time period, becoming highly mechanized and produces finer coal dust particles which are more explosive. Despite the advances in mining technology, mine-wide dust sampling practices have remained...

In the coal mining process, the destabilization of loaded coal mass is a prerequisite for coal and rock dynamic disaster, and surface cracks of the coal and rock mass are important indicators, reflecting the current state of the coal body. The detection of surface cracks in the coal body plays an important role in coal mine safety monitoring. In this paper, a method for detecting the surface cr...

The relationship of conductivity and the frequency, which is of decisive significance in through-theearth wireless communication in coal mine, is closely related to the options of frequency range in coal mine wireless communication. When through-the-earth wireless communication is applied, the electromagnetic waves need to spread in the semi-conductive medium rocks. The main factors affecting t...

In the past decade, there has been a massive growth in the horizontal drilling and hydraulic fracturing of shale gas and tight oil reservoirs to exploit formerly inaccessible or unprofitable energy resources in rock formations with low permeability. In North America, these unconventional domestic sources of natural gas and oil provide an opportunity to achieve energy self-sufficiency and to red...

Based on the deformation and damage characteristics of surrounding rock in a large-section gob-side entry retaining combined with field observations an analysis dominant factors, overall control plan is formulated. The mainly includes structure high strength, stiffness ductility for roadside support; reinforcement roadway-in setup hydraulic fracturing pressure release mechanism advanced long, h...

Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used. These factors have been proposed by various researchers and are depen...

Coalbed methane development primarily relies on hydraulic fracturing and drainage gas extraction processes. The intrusion of external fluids long-term contribute to the water blocking effect, which becomes one crucial factors affecting production capacity. In this study, coal reservoir a certain coalbed in Hancheng, Shaanxi Province, was selected as research object. experimental method employed...