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Our Expertise . . .

Slope Stability Projects (select list)

• Alta Gold Company, Sunnyside Mine, Silverton, Colorado, USA

• Arch Coal Company, West Elk Mine, Somerset, Colorado, USA

• Corriente Resources, Ltd., Mirador Gold Copper Prospect, Ecuador

• Cyprus Plateau Mining Company, Willow Creek, Utah, USA

• Homestake Mining Company, Colorado, USA

• Kennecott Utah Copper Corporation, Utah, USA

• Mesa Rock Company, Colorado, USA

• Mesa County, Department of Public Works, Mesa County, Colorado, USA

• Mountain Coal Company, Utah, USA

• U.S. Army Corps of Engineers Waterways Experiment Station

• U.S. Department of Energy, Yucca Mountain Site Characterization Project, Nevada, USA

• West Ridge Resources, Inc., Price, Utah, USA

Alta Gold Company, Sunnyside Mine, Silverton, Colorado, USA
   Stability of slopes developed to recover surface remnants of vein deposits extracted by underground mining earlier this century was assessed. AAI staff directed Alta Gold geologic personnel in the collection of geologic and structural mapping data to provide the basis of the stability analysis. Potential fault instabilities were identified by stereonet analysis and recommendations for changes in blasting procedures to enhance pit wall stability were made.

Arch Coal Company, West Elk Mine, Somerset, Colorado, USA
   Design of buttressed slope in marginally stable ground at a proposed mine portal excavation. Rock fill buttresses were designed to provide acceptable safety factors for excavated slopes planned in marginally stable colluvium. Limit equilibrium analyses were conducted in support of the buttress design and evaluation of deep-seated slope failure in response to excavation. Geologic mapping revealed a headscarp at the interface with stable, competent ground. This limited the analyses of deep-seated failure to the ground below the headscarp, resulting in favorable safety factors for stability of the slope.  

Corriente Resources, Ltd., Underground Mining Methods Investigations, Mirador Gold Copper Prospect, Ecuador
   AAI provided Corriente with a summary of the costs and efficiencies, as well as rock mass characterization requirements, for successful mass-mining techniques by underground methods in the early stages of their analysis of the new Mirado Gold Copper Venture in Ecuador.

Cyprus Plateau Mining Company, Willow Creek Escarpment Stability Study, Utah, USA
   Evaluation of the potential for subsidence-induced instability for the escarpments along the Willow Creek Valley in central Utah. Recommended setback for total-extraction mining in critical area was determined based on the three-dimensional stress analysis.

Homestake Mining Company, Pitch Reclamation Project, Colorado, USA
   An evaluation of pit-wide slope stability was conducted for a 700-ft-deep, inactive, uranium mine pit. The evaluation was conducted in support of reclamation activities by Homestake. Numerical simulation of complex slope displacement, that was inadequately reproduced by limit equilibrium methods, was conducted using the discrete element code, UDEC. Limit equilibrium analyses were conducted for slopes exhibiting more conventional modes of failure. The models were extended to predict future slope performance in response to worst-case historic piezometric conditions.

Kennecott Utah Copper Corporation, Dry Fork Tunnel Extension Water Management Project, Utah, USA
   Stress analysis and settlement prediction for a fresh water pipeline. The pipeline was planned to be buried with a layer of compacted soil fill and 600 ft of pit waste-rock. Numerical analyses using the finite-difference code FLAC were conducted for this study.

• 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

• Longwall

• Mine Reclamation

• Overcoring Stress Determinations

• Resource/Reserve Evaluation

• Solution Mining

• Subsidence

Abstracts

• Coal

• Hard Rock Mining

• Industrial Minerals

• Oil Shale

• Nuclear Waste

• Numerical Modeling

• Slope Stability

• Tunnels & Tunneling

• Ventilation

Mesa Rock Company, Rock Slope Stability Evaluation, Colorado, USA
   Slope stability analysis for a rock slope overlooking Colorado Highway 141. The evaluation was to determine the ultimate safe slope and assess blasting practice for mine permit.

Mesa County, Department of Public Works, Slope Stability Evaluation of a Reclaimed Slope, Durant Pit—Mesa County, Colorado, USA
   Mesa County had reclaimed a sand and gravel pit highwall by grading to a 2H:1V slope, contour furrowing, and successfully seeding the slope. Unfortunately, the reclamation plan stipulated a 3H:1V slope or flatter. The Colorado Division of Minerals and Geology requested that stability analyses be conducted to demonstrate stability of the model. AAI collected soil samples, designed a comprehensive laboratory testing program, analyzed laboratory data, and conducted slope stability analyses. The evaluation revealed that the existing slope is expected to be stable.

Mountain Coal Company, Gordon Creek Surface Reclamation, Utah, USA
   AAI conducted soil and rock sampling, soil and rock characterization and slope stability analyses of backfill, and slope reclamation efforts for the portal and surface areas for the Gordon Creek #2 and #7 Mines. Soil and rock samples were collected from the site and submitted for particle size testing and determination of material properties. The data obtained was subsequently incorporated, along with site geologic and hydrologic data, to determine reclamation configurations providing stable slopes.

U.S. Army Corps of Engineers Waterways Experiment Station, Expert System for Diagnosis Seepage Problems Associated with Dams
   The expert system, EXSEL, was developed as a tool for practicing civil engineers and geologists to help assess seepage and leakage related problems associated with earth, rock fill, concrete, and roller-compacted concrete dams.

U.S. Department of Energy, Yucca Mountain Site Characterization Project, Nevada, USA
   AAI has provided the DOE with rock mechanics related analytical and field support for the disposal of high-level nuclear waste. The support has involved:

• Geotechnical analysis, including thermo-mechanical and seismic analyses, of various components of the waste repository design.

• Development of methodology for evaluation of excavation stability, shaft design, and ramp design.

• Evaluation of available technologies for sealing and backfilling underground openings.

• Research and demonstrate instruments and develop field testing equipment.

• Instrumentation and construction monitoring of ESF Starter Tunnel and North Ramp.

• Geotechnical logging of surface exploration boreholes.

• Development and Quality Assurance Project Plan and support operation procedures for all tasks.

West Ridge Resources, Inc., Reclaimed Slope Stability Evaluation, Price, Utah, USA
   AAI designed a relatively steep (40 degree) backfill slope to be constructed during reclamation of the West Ridge Mine.  Key components of the slope design include a geogrid-reinforced uncompacted plant rooting zone at the slope face, geocomposite drains, a rockfill toe drain, compacted backfill material, and at least 70% eventual revegetation.  Mt. Nebo Scientific, of Springville, Utah teamed with AAI and designed the revegetation plan.  AAI has represented West Ridge Resources at regulatory agency meetings.