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Our Expertise . . .

Longwall Projects

Andalex Resources, Price, Utah, USA
   Technical review and recommendations presented on the feasibility of converting mining operations in three seams from room-and-pillar to longwall. The project included reviews of the geologic setting, lithology, structure and longwall mineable reserves, as well as evaluation of mine ventilation plan, methane control, ground control plan, and productivity. Longwall shield load capacity requirements were generated. A ventilation survey and network modeling were performed, leading to recommendations for new fan equipment for the Aberdeen Mine.

Arch of Kentucky, Lynch, Kentucky, USA
   Based on underground observations, gate pillar instrumentation and computer analyses, a mine layout design was developed for coal burst control under 2200 ft of cover. The performance of existing longwall shields was reviewed and recommendations for replacement shields presented. The work involved coordination of geotechnical investigations with the USBM and resulted in development of water infusion techniques for coal burst control.

ARCO Coal, Gordonstone Colliery, Australia
   Longwall mine design in the areas of ground support, gateroad pillar design, and longwall face support capacity.

ARCO Coal, Somerset, Colorado, USA
   Based on review of an extensive geologic study, inspection of existing workings, and analysis of available rock mechanics data, three-seam mine layouts were developed for a large coal reserve with 80- to 240-ft seam interburden and 200- to 1800-ft cover depth. Designs were developed for both room-and-pillar and longwall mining. The mining impact on overlying reserves was evaluated as well as surface subsidence.

Costain Coal Company, Caney Creek, Kentucky, USA
   Reviewed ground conditions and developed ground control recommendations for longwall panel development and retreat.

Colowyo Coal, Meeker, Colorado, USA
   Performed laboratory testing on core and longwall pre-feasibility study.

Cyprus Plateau Mining Corporation, Price, Utah, USA
   A four-part study was conducted of the Willow Creek Property including an evaluation of subsidence potential and escarpment stability, a structural mine design for initial mining in the D-Seam, and an evaluation of longwall support yield capacity involving block modeling.

Cyprus Shoshone, Hanna, Wyoming, USA
   An integrated computer-aided analysis was conducted to compare the stability and spontaneous combustion potential for two- and three-entry gateroad systems.

Cyprus Shoshone, Hanna, Wyoming, USA
   Shield performance was monitored to evaluate mechanisms of yielding and plastic deformation of the shield canopies. Cave conditions and stress redistributions were monitored. It was concluded that damage could be minimized by operator training to set the shields perpendicular to the roof and floor.

• Mining Engineering

• Ventilation Engineering

• Highwall Mining

• Blasting & Explosives Eng.

• Solution Mining

• Rock Mechanics

• Rock Testing

• Stress Measurements

• Forensic Engineering

• Geology & Drilling Management

Project Summaries - Mineral

• Base Metals

• Coal

• Fertilizer Minerals

• Gold

• Limestone

• Oil Shale

• Trona

• Other

Project Summaries - Capability

• Backfill

• Block Caving

• Directional Drilling

• Forensics

• Geologic Studies

• Mine Reclamation

• Overcoring Stress Determinations

• Resource/Reserve Evaluation

• Slope Stability

• Solution Mining

• Subsidence

Abstracts

• Coal

• Hard Rock Mining

• Industrial Minerals

• Oil Shale

• Nuclear Waste

• Numerical Modeling

• Slope Stability

• Tunnels & Tunneling

• Ventilation

Energy West Mining Company, Huntington, Utah, USA
   A review of existing geotechnical and geological data was conducted to provide a basis for recommendations for the instrumentation of longwall panels in both the Deer Creek and Cottonwood Mines. The information developed was incorporated into numerical model analyses to investigate bounces and to develop recommendations for design modifications for longwall gateroads to minimize the potential for bounce occurrences.

FMC Wyoming Corporation, Green River, Wyoming, USA
   A comparative stability evaluation for the East Longwall Panel 8 gateroads was made. Four different gateroad designs were analyzed, including three- and four-entry layouts. Analyses were performed using SALT4 and EXPAREA, both of which can model time-dependent salt behavior. SALT4 was used for 2D analyses of gateroad profile stresses, while EXPAREA was used to analyze vertical pillar stresses. An instrumentation program was implemented to confirm the modeling effort. Recommendations were made and adopted for longwall design improvements.

GENWAL Resources, Inc., Huntington, Utah, USA
   A longwall feasibility study was conducted for deep cover mining under difficult conditions including numerical analysis, gateroad design, longwall support capacity specifications, reserves, and productivity analysis.

Island Creek, Mt. Storm, West Virginia, USA
   The Potomac Division Mines have utilized longwall techniques for more than a decade to extract coal from the Upper Freeport Seam. To increase productivity and reduce material costs, a study was completed consisting of underground observations, stress determinations, and computer-aided design.

Island Creek, Lexington, Kentucky, USA
   Stress determinations were undertaken at the Providence No. 1 Mine to evaluate the causes of cutter roof problems and to recommend alternative mine layouts to remedy the problems.

Kaiser Coal, Raton, New Mexico, USA
   The impact of the number of gateroad entries on the stability of longwall mining in two-seam mining was evaluated for layouts using two to three entries and "yield" pillars based on field measurements and computer analyses. A tailgate support system was also designed to ensure open tailgates for access. Expert witness assistance was also provided at court hearings.

Kaiser Engineers, San Francisco, California, USA
   Performed preliminary geotechnical longwall design as part of a feasibility project in conjunction with Kaiser Engineers Pty., Ltd., Newlands Underground Project.

Meridian Minerals, Englewood, Colorado, USA
   A geotechnical program was implemented for the Bull Mountain Project, Montana, consisting of geologic mapping, core logging, mechanical property testing, and computer-aided stability analyses. Based on the results, an optimum longwall mine design was developed and face support capacity was determined. Subsidence evaluations were also completed.

Meridian Minerals, Englewood, Colorado, USA
   The cavability of massive overburden strata and minimum cover requirements for longwall mining were evaluated using a geotechnical review and computer analyses. The impact of longwall mining on surface resources, consisting of land, wildlife, and groundwater was also assessed.

Mettiki Coal Corporation, Oakland, Maryland, USA
   Ground control inspection and recommendations for longwall coal mine with ground control problems.

Monterey Coal Company, Carlinville, Illinois, USA
   A comprehensive ground control study for the extraction of reserves adjacent to the No. 1 Mine was conducted. The study included reviews of existing geotechnical data, roof support plans, and design factors. In situ stress determinations of horizontal stresses in the immediate roof were conducted and numerical model analyses of mine entry and pillar orientations, cut lengths, and crosscut offset distances were performed to determine the influence of these factors on mine opening stability. Recommendations were developed regarding panel orientation, intersection offsets, cut lengths, pillar and entry dimensions, and longwall shield capacity. In addition, an outline for a practical rock mechanics program was prepared.

Pittsburgh & Midway, Raton, New Mexico, USA
   Longwall design and roof support review. Recommendations made for improvements of ground control problems.

Plateau Mining Company, Price, Utah, USA
   An instrumentation and monitoring program was designed for the purpose of cave progress evaluation and mine design for a three-seam coal mine. In addition, the existing two-seam mine layouts were evaluated and alternative layouts were recommended to increase safety and productivity. Seven alternative gateroad support systems were field tested and an optimum support system was recommended to ensure keeping the tailgate open. The impact on longwall mining on surface subsidence and stream flow was evaluated for two-seam mining, and assistance provided in layout design for a newly acquired property.

Southern Utah Fuel Company, Price, Utah, USA
   Ground control problems associated with the existing gate pillar layout were back-analyzed to provide design input for evaluation of three alternative gate pillar layouts.

Standard Oil Company, Phillippi, West Virginia, USA
   Stress measurement and evaluation of the stability of gateroads under high horizontal stresses were undertaken; alternative layouts were proposed and analyzed to minimize roof instabilities.

Sunnyside Coal Mining Company, Price, Utah, USA
   Review of geotechnical and mine operating data was conducted to investigate the occurrence of longwall bounces and assess the application of de-stressing techniques to reduce the potential for bounces. In addition, recommendations for further data acquisition, monitoring, and analyses were developed.

Twentymile Coal Company, Oak Creek, Colorado, USA
   Mine layouts and support systems were designed for the most productive longwall mining at the Foidel Creek Mine. Assistance was provided for the design of longwall face support and in evaluating the impact of longwall mining on surface hydrology and subsidence. Site visits and stress determinations were performed to verify the longwall design in cooperation with the USBM.

U.S. Bureau of Mines
   Measurements of roof movements and entry closures along four longwall panel gateroads and one room-and-pillar panel were integrated to establish simple, practical measurements for the detection of roof instabilities in coal mines.

Utah Fuel Company, Price, Utah, USA
   Three-seam mine layouts were reviewed and longwall layouts developed for good stability in mining the Upper O'Connor Seam and minimal interaction problems in the lower seams 40 to 90 ft below under a variable cover of 400 to 1200 ft.

Utah Power & Light Company, Huntington, Utah, USA
   Extensive field measurements and computer analyses were performed for the design of longwall gateroads and main entry pillar sizes for optimum stability and resource recovery in two- and three-seam longwall mining under variable cover up to 2300 ft and variable interburden between 20 to 100 ft at the Deer Creek and Wilberg Mines. Other analyses were performed for the comparison of gateroads using two- and three-entry systems and assistance provided for court hearings brought up by the labor union against the use of a two-entry system.

Utah Power & Light Company, Huntington, Utah, USA
   Computer analyses and roof monitoring were conducted for support system design for long-term stability of the mains with spans reaching up to 24 ft at the Cottonwood Mine.

Ziegler Coal, Coulterville, Illinois, USA
   Feasibility of full-extraction mining techniques for shallow Illinois mines were investigated for the No. 11 Mine. The work consisted of an in-depth geotechnical review, underground observations, plate-bearing testing, and subsidence calculations