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SME-ICGCM (1801)
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TITLE Strata Control Investigations During Fully Mechanized Coal Pillar Extraction in Indian Coalfield
SUMMARY Considering the importance of a fully mechanized depillaring operation, the Indian coal mining industry has introduced a number of such depillaring operations at depths of cover ranging from 60 m to 377 m. The overlying strata of these depillaring faces vary widely from highly laminated, weak and easily caveable to massive, strong and difficult to cave. Most of these mechanized depillaring operations were carried out in difficult site conditions, however, performance monitoring in the field has ...
AUTHOR Singh, Rajendra
TITLE A Case Study of Topography?Related Stress Rotation Effects on Multi?seam Stability
SUMMARY The complex interaction between multiple seam pillar extraction panels and variable topography can generate unexpected ground control problems. This case study describes stress-related damage in multiple seam workings that resulted in difficult operating conditions and compromised the safety of the support crews. The damage appeared to be caused by horizontal stress but the unexpected location of the damage baffled the authors. A 2D Finite element analysis was conducted of the mine layout and su...
AUTHOR Tulu, Ihsan Berk
TITLE The Science of Empirical Design in Mining Rock Mechanics
SUMMARY "Many problems in rock mechanics are limited by our imperfect knowledgeof the material properties and failure mechanics of rock masses. Mining problems are somewhat unique, however, in that plenty of real world experience is generally available and can be turned into valuable experimental data. Every pillar that is developed, or stope that is mined, represents a full-scale test of a rock mechanics design. By harvesting these data, and then using the appropriate statistical techniques to interpre...
AUTHOR Mark, Christopher
TITLE Introduction of a New Superior Coating on Ground Support Products
SUMMARY Corrosion can often cause significant strength reduction and failure of steel rockbolts, thus demanding continuous rehabilitation and posing challenges to underground mines in maintaining long term ground support. The mining industry has traditionally applied galvanized and epoxy coatings for protection of ground support and reinforcement in corrosive environments due to cost considerations. However, under a harsh and corrosive groundwater condition with extreme pH levels, failure of the exist...
AUTHOR Oler, Renn
TITLE Inflatable Rock Bolt Bond Strength vs. Rock Mass Rating (RMR): A Comparative Analysis of Pull-Out Testing Data from Underground Mines in Nevada
SUMMARY "Inflatable rock bolts are commonly utilized for ground support in Nevada underground mines, however, there is limited information regarding what factors influence the bond strength of these bolts. Bond strength is an important parameter in friction bolt support design, and this information is usually not available from manufacturers as a standard. Previous research has investigated the bond strength of friction bolts; however, these studies focused primarily on split set bolts and ground condit...
AUTHOR Barnard, Chase K. (primary); Kallu, Rajagopala ; Warren, Sean ; Thareja, Rahul
TITLE Dynamic Failure in Coal Seams: Implications of Coal Composition for Bump Susceptibility
SUMMARY "IntroductionDynamic failure events in an underground coal mine, or“bumps,”are defined as“the sudden, violent bursts of coal from a pillar or pillars or a block of coal, resulting in a section, the whole pillars, or the solid block of coal being thrown into an open entry”(Peng, 2008). Reports of disastrous and often fatal dynamic failure events date back over one hundred years in the United States. Mining practices and technologies have significantly evolved over the course of the last century, ...
AUTHOR Lawson, Heather E. (primary); Weakley, Andrew ; Miller, Arthur
TITLE Underground Measurement of Gateroad Stability at the Depth Around 1000m
SUMMARY "The Carboniferous coal measures, mined across Europe including the major European underground coal mining countries of Poland, UK, Germany, and Czech Republic, suffer from increasing extraction depth. This results in major geomechanics problems associated with ground control and support design.With production being concentrated into ever fewer high performance longwalls, located at greater and greater depth, pressure to ensure the roadways’functionality (required dimensions) continues to increa...
AUTHOR Lubosik, Zbigniew (primary); Prusek, Stanislaw ; Wrana, Aleksander ; Walentek, Andrzej
TITLE Measurements of Horizontal Shear Movements Ahead of Longwall Mining and Implications for Overburden Behaviour
SUMMARY "An underground coal mine located in New South Wales has a target coal seam located 160-180 m deep directly below a 16-20 m thick conglomerate unit that has been associated with significant periodic weighting events on the longwall face. As part of the investigations to better understand the causes of periodic weighting at the mine, inclinometers capable of measuring horizontal shear movements through the full section of the overburden strata were installed ahead of mining at two locations appro...
AUTHOR Mills, Ken W. (primary); Puller, Jesse ; Salisbury, Owen
TITLE Laboratory Studies on Creep Behavior of Grouted Tensioned Rebar in Weak Strata
SUMMARY "Primary roof support in underground coal mines in the USA consists mostly of fully grouted passive rebar or grouted (partially or fully) tensioned rebar. Research conducted at two room-and pillar coal mines in the Illinois Basin and one longwall mine in Colorado monitored the performance of these passive and active rock bolts under similar geologic and mining conditions and found no significant initial loads in either passive or active rock bolts (Spearing et al., 2011). Active rock bolts showe...
AUTHOR Spearing, Anthony (Sam) J. S. (primary); Mishra, Aditya ; Tirumalaraju, Naga S. Y. ; Hirschi, Joseph
TITLE How Interface Friction and W/H Ratio Affect the Mode of Failure of Coal Specimens
SUMMARY "Bumps in coal mines have been recognized as a major hazard for many years. These sudden violent failures around mine openings have compromised safety, ventilation and access to mine workings. Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height (W/H) ratio of a coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive...
AUTHOR Rashed, Gamal (primary); Peng, Syd