The seminar program includes the following keynote presentations:
Keynote 1: Changes in Tailings – Questions and a Focus on Solutions from the Oil Sands
Patrick Sean Wells, Suncor Energy, Canada
Commercial development of the oil sands in north-eastern Alberta, Canada, has accelerated over the past decade. This acceleration has brought both challenges and opportunities to many areas of industrial technology, including tailings. Operators in the region, some with little previous experience in the area of mine tails, have had to learn at a rapid pace. This has produced a series of rippling impacts to the industry, including increased draws on people, accelerated development, expanded spends on technology, as well as almost unprecedented industry wide collaborations and growth in intellectual property. This rapid pace has brought with it many questions, but also a focus on producing solutions for the oil sands industry and beyond.
Sean graduated with a degree in Geological Engineering (with Distinction) from the University of Saskatchewan in 1997. He started his mining career as an underground Beat Geologist with Placer Dome for 5 years at the Campbell Mine in Red Lake, Ontario.
He relocated in 2002 to Fort McMurray, Alberta with Suncor Energy, Inc. as a Short Range then Long Range Tailings Planner. He moved to a dedicated Tailings Research role in 2006, followed by a new role as Manager of Reclamation Research Engineering in 2007. Appointed to his current role in 2011, he moved to Calgary in 2013 and leads a team of senior scientists and engineers focused on the development and implementation of new technologies at Suncor’s upstream production assets in Alberta.
One of his successful projects is the design and development of the MFT Drying process. He is an author of over 20 papers presented at various conferences. He has represented industry research groups as Chair of the CONRAD Tailings Working Group, the Technical Committee for the Oil Sands Tailings Consortium, and is involved with COSIA as Suncor’s representative on the Tailings Measurement Steering Committee. He is a registered Professional Engineer in Alberta and Ontario.
Keynote 2: Where Mining Meets the Public – And Why is Water so Important?
Mike Jacobs, Goldcorp, Canada
Oftentimes tailings storage facilities are constructed downstream of the processing facilities and near property boundaries. And water management is almost always a concern. Water and tailings are two issues that symbiotically grow in significance and frequently surface at a point where “the mine meets the public”. Best practices, safe operations, communication and partnerships are essential for tailings management success. This presentation will discuss Goldcorp’s overall approach to water management and tailings stewardship. It will also specifically address improved tailings management at the Musselwhite Mine in northwestern Ontario, Canada and the field performance of its thickened tailings operation. In 2010 Musselwhite converted its tailings operation from conventional slurry to a thickened operation, thereby reducing the volume of water placed into the impoundment and improving tailings density. Performance results have been monitored and the upstream stacking method has increased the capacity of the tailings impoundment. Water storage requirements and discharge volumes have also been reduced. The tailings thickening system has performed well over a range of feed rates from the mill. Goldcorp is now taking a similar approach at many of its mines worldwide.
Mike Jacobs is Goldcorp’s Director for Water & Tailings. He is responsible for Goldcorp’s tailings stewardship program, strategic planning, and design, implementation, and inspection of tailings storage facilities and major water storage and conveyance infrastructure. He directs Goldcorp’s focus on implementing best practices and technologies, and providing operations “safe enough for our families” for all tailings and significant water management operations. Mike has engineering degrees from Colorado State University and the University of Colorado, is a registered professional engineer in several US states, is a chartered professional engineer in Australia and a registered professional engineer in Queensland. Over the past 34 years he has worked on numerous mining projects on six continents.
Keynote 3: Dry Stacking Operation at Pogo Mine, Alaska
Makoto Umedera, Sumitomo Metal Mining Pogo LLC, USA
Sumitomo Metal Mining Pogo LLC (Pogo) is the operator of the Pogo gold mine, located near Delta Junction, Alaska. The mine has been in operation since 2006, with production of between 380,000 to 400,000 ounces of gold annually. The mine site is located near the Goodpaster River, which is a major tributary to the Tanana River in the Yukon drainage. Chinook salmon is the primary anadromous species utilizing the upstream portion of the Goodpaster River.
Pogo mine was designed with unique features to minimize the impact on the environment, particularly on the Goodpaster River. Flotation with Cyanide Leach/Carbon-in-Pulp (CIP) of concentrate was selected to minimize the amount of cyanide-impacted tailings. CIP tailings are mixed with cement and used to backfill mined stopes in the underground. Flotation tailings are dewatered and disposed of on the surface in a Dry Stack Tailings Facility (DSTF). Waste rocks geochemically classified as “mineralized” are also disposed of in the DSTF and are encapsulated by flotation tailings. Dry stacking was selected based upon geography and site conditions, reduced potential to impact surface and ground water quality, and structural stability of the facility. Proper compaction of tailings is critical to secure the structural stability of the DSTF, and operational procedures were established at Pogo to mitigate climatic impacts such as heavy rain and extremely cold weather on compaction. Monitoring for the DSTF includes surface and ground water quality, flow measurement of run-off water, and geotechnical monitoring of the Shells. Three piezometer holes were drilled in the DSTF and vibrating wire piezometers were installed in late 2012 to monitor the pore pressure and ground temperature. These monitoring data have been and will continue to be used for the DSTF closure study.
Dry stacking at Pogo has presented some challenges. Frequent mechanical failure and excess wear of filter cloths reduced the availability of filter presses. In addition, a longer cycle time for dewatering was required to achieve targeted water content, which resulted in the installation of a supplemental filter press. The mechanical issues of filter presses were solved by improving the operation and maintenance procedures, such as increased frequency of washing. This operational know-how may be beneficial for other dry stacking projects. The original DSTF approached its capacity much earlier than anticipated during the feasibility study. The DSTF was designed based on the “zonation” concept, which separated the DSTF into the General Placement Area (GPA) and Shells to improve operational flexibility. The original construction plan assumed that the GPA and Shells would be constructed simultaneously; however, the Shells were not constructed until the construction design and procedure of the Shells were established in 2010. Therefore more material was placed at the GPA and the surface of the GPA rose more quickly than planned. Then, Pogo expanded the capacity of the DSTF from 7 million metric tonnes to 18 million metric tonnes in 2013. Some suggestions on the construction design of the DSTF will be presented based on the experience at Pogo mine.
Makoto Umedera is a senior project engineer at the Pogo Mine, who has worked at Pogo intermittently for nine years in total since 1997. He has been involved in environmental baseline studies, permitting process, and various engineering studies such as dry stack tailings facility expansion project.
His background is mining engineering. He joined Sumitomo Metal Mining Company in 1988, and spent much of his time at various mine sites including Hishikari Gold Mine in Japan, Mt. Isa Mines and Northparkes Mines in Australia.
He is a professional engineer registered in State of Alaska, and also a registered mining engineer in Japan.