ground failures in coal mines with weak roof
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ground failures in coal mines with weak roof

Ground Failures in Coal Mines with Weak Roof

2012-8-30  Ground Failures in Coal Mines with Weak Roof Greg Molinda, MS Lead Research Scientist ([email protected] dc.gov) Chris Mark, PhD . Principal Research Engineer ([email protected]) National Institute for Occupational Safety and Health (NIOSH) P.O. Box 18070, Cochrans Mill Rd. Pgh., PA

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CDC - Mining - Ground Failures in Coal Mines with Weak ...

Mining Publication: Ground Failures in Coal Mines with Weak Roof. Coal miners who work and travel under supported roof expect to be protected from rock falls. However, rock fall accidents and injuries continue to occur in coal mines that have been

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(PDF) Ground Failures in Coal Mines with Weak Roof

Unplanned roof failures in coal mines can be caused by a number of different factors. These include ... and Control of Coal Mine Roof in Weak Ground, NIOSH Information Circular [2010] (in .

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NIOSHTIC-2 Publications Search - 20037348 - Ground ...

Coal miners who work and travel under supported roof expect to be protected from rock falls. However, rock fall accidents and injuries continue to occur in coal mines that have been supported according to the roof control plan. Experience at coal mines with large numbers of falls indicates that many have weak roof. Control of this roof may require additional ground control measures.

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Building Capacity and Enhancing Long-Term Coal mine

2016-9-1  Research in ground control for underground coal mines spans significantly more than 50 years. Although the problems are multi-faceted, one enduring and persistent issue remains – that of roof failures associated with weak shales due to time-dependent and moisture-sensitive deterioration.

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Analysis of Roof Failure at the Intersections on a Coal Mining

The objective of this paper is to understand the behavior of the roof and the cause of roof failure of a coal mining. Eleven roof falls occurred in the mine section in sequence. All the roof falls were surveyed, and the geological features were determined which include rock type, mechanical properties, and thickness. The immediate roof thickness was interpolated to determine the cause of the ...

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Preventing Falls Of Ground In Coal Mines With ...

Mines with exceptionally low-strength roof (UCS : 3,500 psi and CMRR ; 40) are much more likely to struggle with roof falls than other mines.: Weak-roof is a particular problem for many room and pillar mines in the Midwestern and Northern Appalachian coal basins.

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Christopher MARK Principal Roof Control Specialist PhD ...

Ground Failures in Coal Mines with Weak Roof. Article. Full-text available. Jan 2010; Greg Molinda. Christopher Mark. Coal miners who work and travel under supported

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Causes of Falls of Roof - Council for Scientific and ...

2021-9-11  Figure 4. Comparison of the roof fall rates and size distributions of roof falls on the selected mines. 12 Figure 5. Causes of all roof falls 13 Figure 6. Localities of all roof falls 13 Figure 7.Timing of all falls 14 Figure 8. Size distribution of all falls. 14 Figure9. Illustration of a roof fall with island bolts, indicating excessive bolt ...

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Investigation of the failure mode of shale rocks in ...

2015-10-1  An example of failure in laminated roof rock in underground coal mines is the “cutter roof”. Hill et al. 7 describe the failure as: “a failure process that initially begins as a fracture plane in the roof rock parallel to, and located at, the roof-rib intersection. The fracture propagates at an angle usually steeper than 60° from the horizontal.”

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Analysis of Roof Failure at the Intersections on a Coal Mining

The objective of this paper is to understand the behavior of the roof and the cause of roof failure of a coal mining. Eleven roof falls occurred in the mine section in sequence. All the roof falls were surveyed, and the geological features were determined which include rock type, mechanical properties, and thickness. The immediate roof thickness was interpolated to determine the cause of the ...

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Christopher MARK Principal Roof Control Specialist PhD ...

Ground Failures in Coal Mines with Weak Roof. Article. Full-text available. Jan 2010; Greg Molinda. Christopher Mark. Coal miners who work and travel under supported

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Roof Instability: What Reportable Noninjury Roof Falls in ...

2014-3-1  Ground falls have historically been responsible for nearly 50% of all fatalities in underground bituminous coal mines (Mark, Pappas Barczak, 2009). Roof bolting in coal mines began on a modest scale in the early 1950s. Since then, the design of bolts, grout systems, accessories and installation techniques has improved significantly.

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Shale Failure Mechanics and Intervention Measures in ...

Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock ...

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Quantitative Precursory Information of Weak Shocking ...

To reveal the mechanism of weak roof shocking in mine roadway arranged in weakly consolidated soft rock strata commonly observed in western China, a bearing system of composite roof composed of weakly consolidated soft rocks and coal layers was proposed. Then, theoretical analysis and numerical calculation were applied for instability failures of the mass bearing system with strong body and ...

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Insights into the Relationships Among the Roof, Rib, Floor ...

2020-10-1  Ground control failures continue to be one of the leading causes of injuries and fatalities in underground coal mining. The roof, rib, floor, and pillars are four areas of potential ground failures that miners, engineers, and consultants are continually evaluating. Quite often, these four underground structures are evaluated independently. A recent push to consider them as a system and in a ...

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trackless mobile machinery in coal mines

Ground Failures in Coal Mines with Weak Roof. The Coal Mine Roof Rating (CMRR) ranges from 30-83 and averages 44. The depth of cover ranges from 25-900 ft and averages 325 ft. Coal mine roof that falls before the installation of roof bolts can be hazardous. From 1995-2008, 24 miners were killed while travelling beneath unsupported roof [MSHA ...

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SKIN FAILURE OF ROOF AND RIB AND SUPPORT

IN UNDERGROUND COAL MINES By Eric R. Bauer1 and Dennis R. Dolinar1 ABSTRACT Skin failures of roof and rib in underground coal mines continue to be a significant safety hazard for mine workers. Skin failures do not usually involve failure of the support systems, but result from rock or coal spalling from between the support elements.

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Shale Failure Mechanics and Intervention Measures in ...

Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock mechanics and shale.

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Coal Mine Roadway Stability in Soft Rock: A Case Study ...

2013-12-1  Roadway instability has always been a major concern in deep underground coal mines where the surrounding rock strata and coal seams are weak and the in situ stresses are high. Under the high overburden and tectonic stresses, roadways could collapse or experience excessive deformation, which not only endangers mining personnel but could also reduce the functionality of the roadway and

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MarkMolinda2010WeakRoofElecJGeotechEng (1).pdf - See ...

- 547 - Ground Failures in Coal Mines with Weak Roof Greg Molinda, MS Lead Research Scientist ([email protected]) Chris Mark, PhD Principal Research Engineer ([email protected]) National Institute for Occupational Safety and Health (NIOSH) P.O. Box 18070, Cochrans Mill Rd. Pgh., PA 15236 ABSTRACT Coal miners who work and travel under supported roof expect to be protected from rock

Read More
Analysis of Roof Failure at the Intersections on a Coal Mining

The objective of this paper is to understand the behavior of the roof and the cause of roof failure of a coal mining. Eleven roof falls occurred in the mine section in sequence. All the roof falls were surveyed, and the geological features were determined which include rock type, mechanical properties, and thickness. The immediate roof thickness was interpolated to determine the cause of the ...

Read More
Preventing Falls Of Ground In Coal Mines With ...

Mines with exceptionally low-strength roof (UCS : 3,500 psi and CMRR ; 40) are much more likely to struggle with roof falls than other mines.: Weak-roof is a particular problem for many room and pillar mines in the Midwestern and Northern Appalachian coal basins.

Read More
Roof Instability: What Reportable Noninjury Roof Falls in ...

2014-3-1  Ground falls have historically been responsible for nearly 50% of all fatalities in underground bituminous coal mines (Mark, Pappas Barczak, 2009). Roof bolting in coal mines began on a modest scale in the early 1950s. Since then, the design of bolts, grout systems, accessories and installation techniques has improved significantly.

Read More
SKIN FAILURE OF ROOF AND RIB AND SUPPORT

IN UNDERGROUND COAL MINES By Eric R. Bauer1 and Dennis R. Dolinar1 ABSTRACT Skin failures of roof and rib in underground coal mines continue to be a significant safety hazard for mine workers. Skin failures do not usually involve failure of the support systems, but result from rock or coal spalling from between the support elements.

Read More
Christopher MARK Principal Roof Control Specialist PhD ...

Ground Failures in Coal Mines with Weak Roof. Article. Full-text available. Jan 2010; Greg Molinda. Christopher Mark. Coal miners who work and travel under supported

Read More
Squeezing failure behavior of roof‐coal masses in a gob ...

Laboratory tests indicated that the 2# coal seam was very weak coal with a uniaxial compressive strength of 13.89 MPa. In mining practice, gob‐side entries are normally driven along the floor of the coal seam, thus, the gateroad roof is composed of weak coal masses.

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Coal Mine Roadway Stability in Soft Rock: A Case Study ...

2013-12-1  The roof of the mining seam consisted of four mudstone layers and two thin coal seams (see Fig. 1).This combined roof mudstone-coal formation had a total thickness of approximately 9 m and was generally very weak, with an uniaxial compressive strength (UCS) of 10–20 MPa.

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Reference, Coal Mining Geology, Kentucky Geological

Aggson, J.R., 1978, Coal mine floor heave in the Beckley coalbed: An analysis: U.S. Bureau of Mines Report of Investigations 8274, 32 p. Aggson, J.R., 1979a, How to ...

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Stress Changes and Deformation Monitoring of Longwall

2016-4-8  Coal pillar stability is strongly influenced by the site-specific geological and geotechnical conditions. Many geological structures such as faults, joints, or rock intrusions can be detrimental to mining operations. In order to evaluate the performance of coal pillars under weak roof degraded by igneous rock intrusion, stress and deformation monitoring was conducted in the affected tailgate ...

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