Measurement & analysis

Detecting Strata Fracturing and Roof Failures from a Borehole Based Microseismic System (PDF, 945 KB, 2008)
This paper describes a case study where a surface-based microseismic system, using triaxial geophones in boreholes drilled from the surface, was deployed at a large limestone mine.

Local Earthquake Tomography for Imaging Mining-Induced Changes Within the Overburden above a Longwall Mine (PDF, 267 KB, 2008)
The objective of this study was to determine whether a qualitative but coherent redistribution of velocity, indicating change in location of induced stress, could be imaged as mining occurred in known locations by using a local earthquake tomography software code.

Microseismic Activity Associated With a Deep Longwall Coal Mine (PDF, 4797 KB, 2002)
A deep longwall coal mine was instrumented with a three-dimensional microseismic system in order to help determine the exact strata mechanics associated with the rock failure, redistribution of stress and the associated gob formation from the longwall. Analysis showed a close correlation between the seismic activity and advance rate, and that the majority of the recorded seismic activity occurs in the immediate area of the advancing longwall face.

Rock Damage Characterisation from Microseismic Monitoring (PDF, 9567 KB, 2001-07)
Outlines the concepts used to correlate rock failure with microseismic events and presents examples of microseismic monitoring together with associated computer modeling of the rock failure from several mine sites.

Stability of Underground Openings Adjacent to the Sink Hole at the NIOSH Lake Lynn Research Laboratory (PDF, 243 KB, 2003)
This paper discusses roof monitoring, the roof movement, the large roof fall, propagation of the roof failures, and the recent support measures undertaken to stabilize the escapeway over a portion of the older limestone mine workings at the NIOSH Lake Lynn Laboratory, a mining health and safety research facility.

Using Ground Penetrating Radar for Roof Hazard Detection in Underground Mines (PDF, 3302 KB, 1996)
Ground penetrating radar (GPR) has been investigated by NIOSH for its potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth to determine the value of GPR for roof hazard detection. Differences in data quality are discussed, as well as suggestions for collecting improved data.

Case studies

Geomechanics of Large Stone Structures: A Case History From the Washington National Cathedral (PDF, 286 KB, 2001-07)
When the Washington National Cathedral showed signs of continuing differential settlement in the early 1990's, the US Bureau of Mines was asked for assistance in monitoring the movements of the massive towers and walls. The paper discusses the major findings of the study, implications for the future of the Cathedral, and conclusions regarding the use of geotechnical monitoring at major national monuments.

Monitoring Coal Mine Seismicity with an Automated Wireless Digital Strong-Motion Network (PDF, 1082 KB, 2008)
This paper describes a seismic network installed in western Colorado in the vicinity of three underground coal mines, its features for user access to data, and then gives two examples of seismic events resulting in some damage to mine workings.

Three Dimensional Microseismic Monitoring of a Utah Longwall (PDF, 171 KB, 2001-07)
Recent NIOSH research focused on a longwall coal mine in Utah with overburden greater than 750 m containing several massive sandstone units. The primary field instrumentation at the site was three-dimensional, full waveform, autonomous microseismic arrays placed underground and on the surface in order to surround the active multipanel longwall district. Overall 13,000 seismic events were detected and located with on-site processing during the five months the panel was being mined, including a magnitude 4.2 event.

Engineering controls

Considerations for Using Roof Monitors in Underground Limestone Mines in the USA (PDF, 1000 KB, 2003-08)
Roof Monitoring Safety Systems (RMSSs) were installed in 13 underground limestone mines in six states. This paper analyzes the data obtained at three of the mines and also provides an overview of the system, data, analysis and applications relevant to the RMSS.

A Correlation Between Seismic Tomography, Seismic Events and Support Pressure (PDF, 1090 KB, 2001)
To study bump mechanisms, conditions in the vicinity of a deep longwall mining face in bump-prone strata were monitored using three discrete systems. Results from the three systems are correlated in an effort to increase understanding of mining-induced stress redistribution and bump potential.

The Relationship of Roof Movement and Strata-Induced Microseismic Emissions to Roof Falls (PDF, 397 KB, 2004)
For the first time in an underground stone mine, the relationship between roof movement and microseismic emissions was examined in conjunction with two distinct roof fall areas. As roof monitoring increases in acceptance and monitoring technology advances, the goal of providing reliable roof fall detection systems to enhance the safety of underground mine workers moves closer to reality.

Remote Monitoring of Mine Seismicity and Earthquakes Using Radio Telemetry, Computers, and the Internet (PDF, 551 KB, 2003-09)
NIOSH and the Stillwater Mining Company worked cooperatively with the Montana Bureau of Mines and Geology to develop a system that would collect seismic data at the Stillwater and East Boulder mines. The purpose was to obtain baseline information on the magnitude and location of mining-induced seismicity to determine if the mines needed multi-channel in-mine monitoring systems. Rapid access to seismic data allows personnel at the Stillwater Mine, Spokane Research Laboratory, and Earthquake Studies Office to evaluate seismic events quickly and respond in ways that may improve the safety of mine personnel underground. Installation of the system also broadened earthquake coverage to south-central Montana, a region previously not covered by the seismograph network.

Roof Monitoring Helps Prevent Injuries in Stone Mines (PDF, 944 KB, 2000-11)
The Roof Monitoring Safety System (RMSS) is described, compared to other roof-monitoring technology, and described in context with proactive ground control plans for stone mines.

Roof Monitoring in Limestone - Experience with the Roof Monitoring Safety System (RMSS) (PDF, 5765 KB, 2000)
This paper outlines the evolution of the Roof Monitoring Safety System (RMSS) and how it can be used in a comprehensive proactive ground control safety program. A case history is described where the RMSS was used in an evaluation of the effectiveness of a mechanical impact sealing machine at an operating limestone mine.

Technology News 475 - Roof Monitoring Safety System for Underground Stone Mines (PDF, 53 KB, 1998)
The Roof Monitoring Safety System (RMSS) provides a safer, simple, and inexpensive means for measuring roof movement; its use in underground stone mines is described.