The work in this topic area is supported by the NIOSH Mining Ground Control program. See the NIOSH Mining Products page for software, guides, training materials or other items related to this topic. |
Data & statistics
Variation of Horizontal Stresses and Strains in Mines in Bedded Deposits in the Eastern and Midwestern United States (PDF, 436 KB, 2003)
This paper describes a study where the variations of the magnitude of the horizon stresses in sedimentary deposits in the eastern and Midwestern U.S. are examined with respect to two factors, the elastic modulus of the rock and the site depth.
Software
AHSM - Analysis of Horizontal Stress Effects in Mining
AHSEM contains two modules to improve mine layouts for control of horizontal stress. For development, the user specifies the orientations of the entries, the crosscuts, and the maximum horizontal stress.
Measurement & analysis
Horizontal Stress and Longwall Headgate Ground Control (PDF, 1365 KB, 1998-01)
Horizontal stresses are caused by global plate-tectonic forces. During 1995 alone they were largely responsible for the closing of two longwall mines in the U.S. This paper presents six case histories of mines that encountered roof falls or difficult ground conditions at the headgate caused by horizontal-stress concentrations.
Performance of Roof Support Under High Stress in a U.S. Coal Mine (PDF, 267 KB, 2004-02)
The primary goal of this project was to obtain detailed data on the interaction between the mine roof and the support elements for use in modeling studies. The study site was a longwall tailgate subjected to high horizontal stress.
Rock Mechanics Study of Lateral Destressing for the Advance-and-Relieve Mining Method (PDF, 1696 KB, 2003-08)
The advance-and-relieve method benefits from lateral destressing associated with mining in laminated rocks and a high horizontal stress regime. This stress control method is based on measurements showing that occurrence of rock failure in the roof and floor of an entry results in redistribution of stresses in adjacent entries. Numerical modeling proved useful in studying the basic mechanics of lateral relief while investigating the sensitivity of results to different geologic and mining parameters using controlled experiments.
Safer Mine Layouts for Underground Stone Mines Subjected to Excessive Levels of Horizontal Stress (http://me.smenet.org/200304/pdf/min0304_25.pdf) (PDF, 3459 KB, 2003-04)
At an underground stone mine in Pennsylvania, a modified stress-control mine layout is reducing the hazardous conditions associated with excessive horizontal stresses. Findings to date show that the stress control layout provides more stable conditions, resulting in a safer environment for the mine workers.
Case studies
Case History of the Response of a Longwall Entry Subjected to Concentrated Horizontal Stress (PDF, 1254 KB, 2007)
NIOSH, RAG Pennsylvania and Strata Control Technologies of Australia collaborated in an intensive study of ground behavior, reinforcement performance, and stress redistribution at the Emerald Mine in Southwestern Pennsylvania. The study site was a longwall tailgate subjected to a severe horizontal stress concentration. A computer simulation of the field site was conducted using FLAC-2D. Comparison between actual field measurements and the simulation showed that the model was able to capture the most significant aspects of the roof and support system behavior. The model also showed that supplementing the normal roof bolt support pattern with cable bolts would allow the entry to survive a further 20-25% increase in the applied horizontal stress.
Utilizing the 'Advance and Relieve' Method to Reduce Horizontal Stress Affects on the Mine Roof, A Case Study (PDF, 2100 KB, 2000)
The practical application of the "advance and relieve" method is discussed, where a pillar is removed on one side of the panel as it is being advanced, creating a cave. A trial of the method was conducted for a room and pillar coal operation that was experiencing roof cutters and long running roof falls caused by high horizontal stresses.
Engineering controls
Advance and Relieve Mining: A Method to Mitigate the Effects of High Horizontal Stress on the Mine Roof (PDF, 5767 KB, 2001)
Evaluation of the "Advance and Relieve" mining method is described to determine effectiveness for conditions where high horizontal stresses caused long running roof falls resulting in hazardous conditions and the premature abandonment of panels. "Advance and Relieve" mining involves the removal of a pillar of a portion of a pillar during development, creating a cave along one side of the panel.
Controlling Roof Beam Failures From High Horizontal Stresses in Underground Stone Mines (PDF, 836 KB, 1998-08)
A design technique is presented which provides stone miners with a method for making stability assessments. The consequences of widening rooms, changing geology and horizontal stresses, and different rock bolts on roof beam failure are discussed.
High Stress Mining Under Shallow Overburden in Underground U.S. Stone Mines (PDF, 358 KB, 2002-11)
This study of the Chestnut Ridge Anticline found that high levels of horizontal stress are to be expected in this very stiff rock formation and that local geologic and topographic structures are capable of altering the magnitude and possibly the orientation of the horizontal stress field.