Last data update: Jun 03, 2024. (Total: 46935 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Ellenberger JL [original query] |
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Analysis of roof and pillar failure associated with weak floor at a limestone mine
Murphy MM , Ellenberger JL , Esterhuizen GS , Miller T . Int J Min Sci Technol 2016 26 (3) 471-476 A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues. Previous NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface. |
Roof instability: what reportable noninjury roof falls in underground coal mines can tell us
Bajpayee TS , Pappas DM , Ellenberger JL . Prof Saf 2014 59 (3) 57-62 Roof falls are a major hazard in underground mining. Roof bolting is the primary means of supporting the mine roof in underground coal mines. Despite great strides in the design of support systems, roof falls continue to occur in bolted areas. Noninjury roof fall reports provide insight into the characteristics of roof falls. This study examined 11,600 noninjury roof fall reports to identify geological contributors to roof falls. The goal is to provide data that can help improve roof-fall-related safety by providing direction for the research and development of improved support systems and mine layout alternatives. |
Pillar strength in underground stone mines in the United States
Esterhuizen GS , Dolinar DR , Ellenberger JL . Int J Rock Mech Min Sci 2011 48 (1) 42-50 Stone mines in the Eastern and Midwestern United States make use of the room-and-pillar method of mining to extract relatively flat-laying sedimentary formations. A survey of pillar performance was carried out to identify potential modes of instability. Pillars were found to have been successful in providing support to the overburden, but a small number of individual failed pillars were observed. Failure of the pillars was observed to be related to spalling of the hard brittle rocks, shearing along pre-existing angular discontinuities or progressive extrusion of soft infill materials on bedding planes. A method of estimating the pillar strength and selecting a safety factor for design was developed based on observations of stable and failed pillars, supplemented by numerical models. The developed pillar strength equation can be used to design stable stone mine pillars provided the rock conditions are similar to those included in the study. Published by Elsevier Ltd. |
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