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Mining Publication: Roof Stability Issues in Underground Limestone Mines in the United States
Keywords: Mine design Products and materials Roof quality Room and pillar mining Stone mining 
 Support design and selection
This page is archived for historical purposes and is no longer being maintained or updated.
Original creation date: July 2007
Authors: GS Esterhuizen, DR Dolinar, JL Ellenberger, LJ Prosser, AT Iannacchione
Conference Paper - July 2007
Download PDF Document (0.68 MB)
NIOSHTIC2 Number: 20032432
Proceedings of the 26th International Conference on Ground Control in Mining, July 31-August 2, 2007, Morgantown, West Virginia. Peng SS, Mark C, Finfinger G, Tadolini S, Khair AW, Heasley K, Luo Y, eds., Morgantown, WV: West Virginia University, 2007; :336-343
The room-and-pillar mining method is used extensively in underground limestone mines in the Eastern and Midwestern U.S. The rock mass is typically a near-horizontal, bedded deposit at relatively shallow depth. A survey of 34 mines was conducted in which data on roof spans, rock mass properties and support practices were collected as part of a National Institute for Occupational Safety and Health research project into ground control in limestone mines. The average room width is 13.5 m (44 ft), accommodating large mechanized equipment. The results show that the immediate roof beam can consist of many individual layers and can contain several near-vertical joints. In spite of the room widths, the roof is naturally stable in many mines. Observed roof instabilities can generally be related to excessive horizontal stresses or unfavorable geological structures that cause block fallout or beam failure of the bedded roof rocks. The survey showed that the rock mass quality of the limestone does not vary significantly throughout the Eastern and Midwestern U.S. Roof conditions and the need for support were found to be closely related to the thickness and competence of the first layer of limestone in the roof. The findings highlight the need to identify local geological structures and the roof beam characteristics so that support alternatives can be evaluated. Monitoring and observational technologies that are available for identifying potentially unstable roof are presented, which include: roof characterization using the Rock Fall Risk Index, automated logging of roofbolt hole drilling, microseismic monitoring and displacement monitoring.
Image of publication Roof Stability Issues in Underground Limestone Mines in the United StatesConference Paper - July 2007
Download PDF Document (0.68 MB)
NIOSHTIC2 Number: 20032432
Proceedings of the 26th International Conference on Ground Control in Mining, July 31-August 2, 2007, Morgantown, West Virginia. Peng SS, Mark C, Finfinger G, Tadolini S, Khair AW, Heasley K, Luo Y, eds., Morgantown, WV: West Virginia University, 2007; :336-343
See Also
Effect of the Dip and Excavation Orientation on Roof Stability in Moderately Dipping Stone Mine Workings
Field Observations and Numerical Studies of Horizontal Stress Effects on Roof Stability in U.S. Limestone Mines
New Developments with the Coal Mine Roof Rating
Pillar and Roof Span Design Guidelines for Underground Stone Mines
Pillar Stability Issues Based on a Survey of Pillar Performance in Underground Limestone Mines
Pillar Strength and Design Methodology for Stone Mines
Roof Span Design for Underground Stone Mines
Stability Analysis of a Backfilled Room-and-Pillar Mine
Technology News 481 - Update: Roof Monitoring Safety System for Underground Stone Mines
Toward Pillar Design To Prevent Collapse of Room-and-Pillar Mines
Page last reviewed: September 21, 2012
Page last updated: September 21, 2012
Content source: National Institute for Occupational Safety and Health, Mining Program
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