Investigating For Dry Stack Tailings Facility Closure: Multidisciplinary Evaluation At The Pogo Mine, Alaska

Автор Daniel Neuffer, Christopher Stevens, Russell Staines

Investigating For Dry Stack Tailings Facility Closure: Multidisciplinary... | SRK Consulting

Авторы

Daniel Neuffer

Christopher Stevens

Russell Staines

Sumitomo Metal Mining Pogo LLC (Pogo) is the operator of the Pogo underground gold mine, located near Delta Junction, Alaska. The mine has been in operation since 2006 and produces between 380,000 and 400,000 ounces of gold annually. Filtered tailings from the flotation circuit and waste rock from the mine are placed in the dry stack tailings facility (DSTF). Expansion of the DSTF from 7 M to 18 M t has prompted further evaluation of the facility for closure planning. This paper presents data from several components of a multidisciplinary DSTF closure study, including geotechnical and geochemical test results, in situ temperature and pore pressure measurements, and estimated freezing characteristics of tailings samples.

Results of this study indicate the DSTF is physically stable and is comprised of materials that are not potentially acid‐generating; these findings support operational material placement practices and elements of the DSTF closure plan. Geotechnical field and laboratory testing indicate that effective friction angles and dry densities of in situ DSTF materials are consistent with previous slope stability analyses. Geotechnical borehole drilling, thermal monitoring, and analysis indicate the presence of permafrost within the DSTF. Pore pressure measurements and drilling observations indicate a phreatic surface near the base of the DSTF. This study narrows the focus of data collection for future closure planning and provides an example of physical and chemical conditions within a dry stack tailings facility in a continental, subarctic climate. These findings are pertinent for planning, design, permitting, operation, and closure of dry stacks in similar climates.

Автор

Daniel Neuffer | Mining Geotechnical Engineer | SRK Alaska, USA

Daniel Neuffer

Principal Geotechnical Engineer

Dan has 23 years of experience focusing on engineering, construction, operation, and closure of tailings, mine waste, heap leach, and mine water facilities.

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