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SME-ICGCM (1801)
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TITLE Aspect Ratio and Other Parameters That Affect the Performance of Burrell Can Roof Supports
SUMMARY The Burrell Can1 is a thin, steel, tubular shell filled with aerated concrete that is used as a roof support in coal mines. The Can height is always shorter than the mining entry, so it is capped with wooden timbers and wedges when it is installed. This combination of the Can and the wooden header is a standing support system that is designed to yield in a controlled manner and exhibit a constant yield, or elastic-plastic behavior. The Burrell Can is capable of withstanding 20 in or more of vert...
AUTHOR Gearhart, David F.
TITLE The Extraction of Main Heading Pillars with a Longwall at Nre Wongawilli Colliery
SUMMARY To maintain longwall continuity, NRE Wongawilli Colliery extracted the approximately 20-year-old Thompson Mains and in doing so, 20 roadways were holed into during longwall retreat. The orientation of these roadways with regard to the longwall face varied between (i) a parallel alignment where the entire roadway was simultaneously subjected to a significant increase in vertical stress on holing and (ii) a more favorable high angle of alignment, meaning that only a portion of the roadway was subj...
AUTHOR Stone, Ry
TITLE Massive Pillar Collapse: a Room?and?Pillar Marble Mine Case Study
SUMMARY The Mine Safety and Health Administration?s Roof Control Division responded to a massive ground failure at an underground marble mine in northern Georgia. The ground failure occurred in a benched area that had been abandoned in the early 1990s. It involved the failure of an estimated 19 pillars, in conjunction with a massive roof fall of an undetermined extent that was at least 60 ft high. Pillars in the benched area had been mined nominally 40 x 40 feet to a height of 50 feet ft, with 40-ft min...
AUTHOR Phillipson, Sandin E.
TITLE Mitigation of a Massive Sandstone Channel's Impact on a 1,500 Ft Wide Longwall Face
SUMMARY This paper presents the implementation and evaluation of the hydraulic fracturing technique and Longwall Visual Analysis (LVA) software to mitigate the impact of a 1,000-ft (305-meter) widemassive sandstone channel on a 1,500-ft-wide (457-m-wide) longwall face. Based on a underground roof geology reconnaissance program, four frac holes were drilled and fraced along the center axis of the sandstone channel. To further provide detailed monitoring of the longwall face, the Longwall Visual Analysis ...
AUTHOR Su, Daniel W.
TITLE A Stability Factor for Supported Mine Entries Based on Numerical Model Analysis
SUMMARY This paper addresses the need for a method to compare the effectiveness of different support systems when designing ground support in coal mines. At present, support design methods include empirical methods based on observations of past performance of installed support systems, analytical methods where the roof is typically simulated by elastic beams and numerical model analysis. The approach presented in this paper estimates the relative stability of a support design through geotechnical evalua...
AUTHOR Esterhuizen, Gabriel S.
TITLE Mitigating the Effects of High Horizontal Stress on Ground Control in An Underground Stone Mine: A Case History
SUMMARY The nature of a stone deposit is rarely defined through exploration and engineering design, but more through the actual experience encountered as the mine develops; hence, issues with ground control are often at the forefront for a new mine. Ground control problems account for over 15 percent of lost-time injuries in underground stone mines. The objective of this work is to present actions taken during early development of a stone mine to mitigate the obvious effects of high horizontal stress on...
AUTHOR Ellenberger, John
TITLE Comparison of the Performance of Active and Passive Roof Bolts in An Illinois Basin Coal Mine
SUMMARY This paper discusses in situ studies conducted at an Illinois Basin room-and-pillar coal mine to evaluate the performances of three different types of bolts under similar geologic conditions. The bolt types considered were the fully grouted passive rebar (FGPR), the resin-assisted mechanical anchor (RMAB), and the fully grouted tension rebar (FGTR). During the evaluations, the three types of bolts were installed in a single entry covering a span of three contiguous pillars with almost identical ...
AUTHOR Ray, Anil K.
TITLE Relocating Mining?Induced Seismicity at the Trail Mountain Mine
SUMMARY From October 2000 to April 2001 a local array of fourteen seismograph stations was deployed at the Trail Mountain Mine (TMM), an underground coal mine in Emery County, Utah, to locate mining-induced seismicity (MIS). Original analysis of the data provided epicentral locations that coincided closely with the active longwall panel. The original analysis yielded poor quality hypocenters, however, preventing a useful relation from being made between mining activity and the event depths. For the orig...
AUTHOR Boltz, Meagan S.
TITLE A Mine Evaluation Protocol Using Applied Rock Mechanics Techniques
SUMMARY The author has developed a seven-step process called the Applied Rock Mechanics (ARM) Protocol that the author has used to solve numerous roof stability problems in mines throughout North America since 1975. It is a practical evaluation process using trained observation, innovative data collection instrumentation, video borehole cameras, analytical processes, and controlled testing methods that have become highly effective in solving ground control problems in every type of underground mine. Thi...
AUTHOR Petersen, Gary B.
TITLE Effects of Transverse Isotropy on Vertical Stresses When Multi?Seam Mining under Supercritical Longwall Panels
SUMMARY The design of effective ground support requires a sound understanding of the pre-mining state of stress in the stratum to be mined. Irregularities in the stress field encountered during multiseam mining are governed primarily by the previous mining in the surrounding strata. The aim of this study is to quantify the effects of rock mass transverse isotropy on the vertical stress redistribution in the rock strata beneath supercritical longwall panels. Wilson?s equations for determining the stress ...
AUTHOR Suchowerska, Anastasia M.