WorldCoal, September 2009Author: Tom Vandergrift (AAI) As open-pit coal mines reach their economic stripping limit, operators sometimes consider alternatives, such as auger mining or highwall mining, to recover additional coal. Highwall mining with rectangular openings offers several advantages over augering, including steeping/guidance capabilities, the ability to adjust to varying seam height and increased penetration beneath [...]
Coal
3rd International Workshop on Coal Pillar Mechanics and Design, Morgantown, West Virginia, July 26, 2010Authors: Tom Vandergrift and David Conover (AAI) Currently accepted longwall abutment gate-road design criteria result in very large pillar sizes under deep cover. This leads to ventilation challenges, and makes it difficult for development to keep pace with longwall retreat. One [...]
2001 SME Annual Meeting & Exhibit, Denver, Colorado, February 2001 Mining Engineering, November 2003 Authors: J. F. T. Agapito and R. R. Goodrich (AAI) Yield pillars have been used for many years to help reduce stresses near mine openings and improve roof and floor stability. A yield pillar is often defined as a pillar that [...]
Mining Engineering, February 1991, pp. 215–219 Authors: J. F. T. Agapito (AAI) Significant economic benefits can result when rock mechanics is applied within a practical framework and integrated within the other engineering functions of the mine organization. This requires management support and understanding of rock mechanics as a practical tool to help attain high standards [...]
3rd North American Rock Mechanics Symposium, Cancun, Mexico, 3–5 June 1998 Authors: L. J. Gilbride, A. M. Richardson, and J. F. T. Agapito (AAI) Simplified design methods based on statics have traditionally been used for determining the capacity of longwall shield supports. However, these methods are mechanically oversimplified in the statically indeterminate loading environment at [...]
American Mining Congress, MINExpo International ’88, Chicago, Illinois, 24–28 April 1988 Authors: J. F. T. Agapito and H. N. Maleki (AAI), and M. Moon (Utah Power & Light Company) Severe pillar bursting at the Utah Power & Light Company’s Deer Creek Mine, Utah, has caused serious safety and ground control problems. The bursts occurred in [...]
4th Conference on Ground Control, West Virginia University, 1985 Authors: H. N. Maleki and M. P. Hardy (AAI), and C. J. H. Brest van Kempen (Brest van Kempen & Associates, Inc.) Tension-torque relationships were investigated in a coal mine for both standard 5/8-in. (16-mm) bolts and a vibrating wire instrumented bolt, using conventional and controlled [...]
5th Conference on Ground Control in Mining, Morgantown, West Virginia, June 1986 Authors: H. N. Maleki and J. F. T. Agapito (AAI), and R. G. Lauman and J. Hatrick (Plateau Mining Company) This paper presents a field evaluation of six tailgate secondary support systems, with the objective of optimizing support efficiency for maintaining open gate [...]
Rock Mechanics for Industry, 37th U.S. Rock Mechanics Symposium, Vail, Colorado, 6–9 June 1999Authors: R. R. Goodrich (AAI), W. K. Sorensen (Canyon Fuel Company), J. F. T. Agapito (AAI), and J. Black (Canyon Fuel Company) Canyon Fuel Company operates the SUFCO coal mine located in the southern Wasatch Plateau Coal Field approximately 48 km (30 [...]
22nd International Conference on Ground Control in Mining, Morgantown, West Virginia, 5–7 August 2003 Author: F. S. Kendorski (AAI) A longwall coal mine in Appalachia about 1,500 ft deep encountered a fault while developing a new longwall panel. The fault extended from mining depth to the surface near a secondary road and drainage. The fault [...]
17th Conference on Ground Control in Mining, Morgantown, West Virginia, 4–6 August 1998 Authors: A. M. Richardson, L. J. Gilbride, and J. F. T. Agapito (AAI) Periodic weighting of longwall supports occurs during retreat of the face under certain geologic conditions. Strong strata in the immediate and main roof tend to cantilever over the gob, [...]
21st U.S. Symposium on Rock Mechanics, The University of Missouri, Rolla, May 1980 Authors: J. F. T. Agapito, S. J. Mitchell and M. P. Hardy (AAI), J. R. Aggson (USBM), and W. N. Hoskins (Tosco Corp.) The concept of vertical stress as being equal to the weight of the overburden is intuitive and relatively accurate [...]
32nd U.S. Symposium on Rock Mechanics, Norman, Oklahoma, 10–12 July 1991 Authors: H. Maleki (AAI) and A. Weaver (Energy Fuel, Southfield Mine) This paper presents the results of stress measurements, underground observations, and stability monitoring in a southern Colorado mine. The objective of the program was to assess the causes for panel stability problems and [...]
Geo-Strata, Fall 2003, pp. 9–12 Author: F. S. Kendorski (AAI) Rock reinforcement has been accepted in mining and construction since the 1950s. The longevity of rock reinforcement is often questioned in engineering design because it’s historical performance is measured in just decades, relies on natural systems to function, and is not easily inspected. The elements [...]
23rd International Conference on Ground Control in Mining, Morgantown, WV, August 3–5, 2004 Author: F. S. Kendorski (AAI) One of the most dangerous events in underground coal mining is unexpectedly encountering water inrushes from undetected abandoned mines in the same seam. The surest and most confident method is probe drilling either from the mine or [...]
25th U.S. Symposium on Rock Mechanics, Evanston, Illinois, 1984 Authors: H. Maleki (AAI), W. Hustrulid (Colorado School of Mines), and D. Johnson (Utah Fuel Company) Gob pressure measurements were made in a Western U.S. coal mine as part of a long-term program to evaluate cave progress and to determine the influence of geological discontinuities on [...]
6th International Conference on Ground Control in Mining, Morgantown, West Virginia, June 1987 Authors: H. Maleki (AAI), T. Carlisle and G. Hunt (Plateau Mining Company), and J. F. T. Agapito (AAI) A novel ground control program has been developed at Plateau Mining Company through five years of geotechnical investigations. The study was initiated to determine [...]
6th International Conference on Ground Control in Mining, Morgantown, West Virginia, June 1987 Authors: H. Maleki and J. Aggson (AAI), F. Miller (Utah Power & Light Co.), and J. F.T. Agapito (AAI) A comprehensive study consisting of stress determinations, core logging, laboratory testing, and numerical analyses was conducted to investigate the cause and potential alternatives [...]
3rd North American Rock Mechanics Symposium, Cancun, Mexico, 3–5 June 1998 Authors: R. R. Goodrich and J. F. T. Agapito (AAI), and C. Pollastro and L. LaFrentz (Energy West Mining Company) Energy West Mining operates the Deer Creek coal mine in the Wasatch Plateau about 40 km (25 miles) southwest of Price, Utah, United States [...]
Rock Mechanics for Industry, 37th U.S. Rock Mechanics Symposium, Vail, Colorado, 6–9 June 1999 Authors: R. R. Goodrich and J. F. T. Agapito (AAI), and C. Pollastro, L. LaFrentz and K. Fleck (Energy West Mining Company) Energy West Mining Company operates the Deer Creek coal mine located in the Wasatch Plateau about 40 km (25 [...]
23rd International Conference on Ground Control in Mining, Morgantown, West Virginia, August 3–5, 2004 Authors: L. J. Gilbride and M. P. Hardy (AAI) Western U.S. longwall operators face increasing challenges with optimizing ground control and productivity as mines reach greater depths and coal bursting hazards increase. Some western U.S. mines, many known to be bump-prone, [...]
7th International Conference on Ground Control in Mining, 3–5 August 1988 Authors: H. N. Maleki and J. F. T. Agapito (AAI), and M. Moon (Utah Power & Light Company) Extensive measurements and underground observations in three Western U.S. coal mines are integrated in this paper to determine in-situ pillar load-deformation characteristics for narrow (30-ft-wide, 80-ft-long) [...]
27th U.S. Symposium on Rock Mechanics, The University of Alabama, 23–25 June 1986 Authors: H. N. Maleki and M. P. Hardy (AAI), and C. J. H. Brest van Kempen (Brest van Kempen & Associates, Inc.) To evaluate the influence of uniformly tensioned roof bolts on roof stability, mechanically anchored roof bolts were installed using the [...]
24th International Conference on Ground Control in Mining, Morgantown, West Virginia, USA, August 2-4, 2005 Authors: J. F. T. Agapito and L. J. Gilbride (AAI), and W. A. Koontz (Ark Land Company) Overcore measurements at the North Fork Valley (NFV) coal mines in western Colorado have shown that horizontal stresses are highly anisotropic. Measurements have [...]
24th International Conference on Ground Control in Mining, Morgantown, West Virginia, USA, August 2-4, 2005Authors: T. Vandergrift (AAI) and J. Garcia (Kennecott Energy, Colowyo Mine) With advances in system design driving higher productivity, safety, and coal recovery, highwall mining is becoming an attractive option for extending reserve life at surface mines. Typically, highwall mining is [...]
7th International Conference on Ground Control in Mining, 3–5 August 1988 Authors: H. N. Maleki (AAI), R. D. Tifft III (Cyprus-Yampa Valley Coal Company) and M. P. Hardy (AAI) The results of five years of geotechnical investigations are presented to develop productive and stable longwall layouts for the Foidel Creek Mine. The program was initiated [...]
SME Annual Meeting, Phoenix, Arizona, 25–28 January 1988, Preprint No. 88-5 Authors: J. R. Aggson (AAI) In an effort to minimize cutter roof failure in longwall development entries of a West Virginia coal mine, a three-entry system was developed with the center entry arched into the strata above the coal seam. The purpose of the [...]
International Journal of Mining and Geological Engineering, 4:111–127, 1986 Authors: H. N. Maleki and J. F. T. Agapito (AAI), and M. Wangsgard and J. Cort (Plateau Mining Company) Results of instrumentation, test mining, and computer-aided stability analyses were combined to design the most stable gate road layout for two-seam longwall mining at the Plateau Mining [...]
Nineteenth International Congress on Rock Mechanics, Paris, France, 25–28 August 2000 Authors: J. F. T. Agapito and R. R. Goodrich (AAI) High stresses and adverse geology in deep coal mines in the state of Utah, USA, have caused numerous bursts. The larger bursts have been associated with seismic events with Richter magnitudes of 3.6, and [...]
26th U.S. Symposium on Rock Mechanics, Rapid City, South Dakota, 26–28 June 1985 Authors: H. N. Maleki and M. P. Hardy (AAI), and C. J. H. Brest van Kempen (Brest van Kempen & Associates, Inc.) Performance characteristics of an instrumented bolt utilizing the vibrating wire gages were evaluated through 140 field and laboratory tests. Evaluations [...]
25th International Conference on Ground Control in Mining held in Morgantown, West Virginia, USA, 2006 Authors: Francis S. Kendorski (AAI) Over the past 25 years, the present author has written with several co-authors a series of papers beginning with the landmark paper in the 1st International Conference on Ground Control in Mining in 1981, in [...]
26th International Ground Control Conference in Mining, 2007 Authors: Francis S. Kendorski (AAI) and Mark D. Bunnell (Ark Land Company) The Skyline #3 Mine of Canyon Fuel Company in Utah was planning longwall mine development adjacent to and downdip of older mine workings known to be flooded. Barrier pillar geometries and widths were proposed by [...]
Mining Engineering, July 1997 Authors: J. F. T. Agapito and R. R. Goodrich (AAI) and M. Moon (Energy West Mining Co.) Experience at Energy West Mines in the Wasatch Plateau Coal Field, Utah, has shown that longwall face bursts occur mostly near the tailgate when extracting the third adjacent longwall in a panel section where [...]
International Symposium on Mine Mechanization and Automation, Golden, Colorado, 10–13 June 1991 Authors: H. N. Maleki (AAI) Expert systems have found applications in a number of engineering problems within the last decade. Continuous ground control monitoring systems are currently being installed in coal mines for research purposes. This paper presents a critical evaluation of the [...]
3rd Conference on the Use of Computers in the Coal Industry, Morgantown, West Virginia, 30 July 1986 Authors: C. M. St. John and H. N. Maleki (AAI) Today it is practical to perform geotechnical analyses of mining excavations using microcomputers. This paper describes three computer programs that may be used for that purpose and their [...]
25th International Ground Control Conference on Ground Control in Mining, 2006 Authors: Tim Ross and Bo Yu (AAI) and Chris Nyikos (Mountain Coal Company, LLC) Several shear failures were observed in Shaft #1 at the Mountain Coal Company, LLC, West Elk Mine, after mining longwall Panel 23, 1,100 ft to the east of Shaft #1. [...]
