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Keynote Speakers – Tailings and Mine Waste Conference
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Keynote Speakers

Tailings and Mine Waste Conference

Featured Presentations

Mind the Gap: Innovations in Geochemical Management of Tailings and Mine Waste

Dr. Heidi Cossey, co-presented by Kristin Salzsauler

Abstract:

Recent failures of tailings storage and heap leach facilities have highlighted the importance of achieving both chemical and physical stability of these structures. Geochemical management planning is complex and multidisciplinary, often relying on commitments made during early stages of the mine life cycle that may evolve as projects mature.

This keynote session will critically examine conventional approaches to geochemical management of mined materials, highlighting tensions with geotechnical best practices and identifying persistent knowledge gaps. This session will explore opportunities for innovation in mine waste characterization and management. Case studies will illustrate emerging practices aimed at enhancing physical and chemical stability.

Finally, we will discuss systemic barriers to innovation, including regulatory constraints and risk aversion, and propose strategies to foster more integrated, adaptive, and forward-looking approaches to geochemical planning.

Beyond GISTM – The Next Era in Safe Tailings Facilities

Scott Martens

Abstract:

It has been 5 years since the Global Industry Standard on Tailings Management (GISTM) was released, which was prompted by a series of notable TSF failures. International Council on Mining & Metals (ICMM) member companies have now publicly disclosed the status of conformance with the GISTM requirements for all of their tailings facilities. GISTM is a core component of transformative change that is happening in tailings management.

There have been no catastrophic failures of tailings facilities that were managed in accordance with GISTM or the Mining Association of Canada’s (MAC) Towards Sustainable Mining (TSM) program. But what comes next? Is GISTM enough to achieve what the industry needs and the public rightfully demands for safe and responsible tailings management? There are several themes that warrant focus when implementing GISTM, and areas to build on or extend GISTM. These include: technical guidelines; robust designs; understanding and management of uncertainty; effectiveness of risk management procedures; design and construction quality assurance; transparency in risk communication with senior leadership and independent reviewers; and areas for further research.

The efforts to implement the requirements of GISTM have been significant, and the process is not finished with disclosure of conformance. GISTM provides a framework for safe and responsible tailings management, and it requires achieving a standard, maintaining that standard, and going beyond the minimum standard with robust designs and effective procedures.

GeoStable Trials – Exploring the Future of Commingling and Integrated Mine Waste Management

Dennis Rugg, co-presented by Tamara Butler Johndrow

Abstract:

Freeport-McMoRan Inc. (Freeport) is a founding member of the GeoStable Tailings Consortium (GSTC), which was formed in 2020 to advance the understanding, development, and implementation of commingled tailings and waste rock in support of safe and sustainable management of mine waste materials. Freeport began the planning and design for a GeoStable Trial Project at the Sierrita mine in 2022. The project includes laboratory testing for geotechnical, geochemical, and material handling properties of various commingled mixtures, field conveyability and mixing trials on over 25 commingled mixtures, six lined and fully instrumented commingled trial pads, 17 geochemical rain barrels, and field data collection and monitoring. Construction of six trial pads was completed in June 2025 and monitoring is ongoing.

Freeport’s GeoStable Trial Project objectives are to improve the understanding of commingled waste rock and tailings from geotechnical, hydrotechnical, geochemical, and material handling perspectives. All aspects of the project are designed to support engineering, design, modelling, and development of the business case for future implementation of full-scale integrated mine waste management.

This keynote presentation outlines Freeport’s GeoStable Trial Project journey from conception through design, construction, and monitoring. Key outcomes and learnings identified during each aspect of the project will be summarized and presented. While there are still unknowns regarding full-scale implementation, outcomes from mixing and conveyability trials and from commingled trial pad design and construction indicate that integrated mine waste management at a high throughput mining operation could be within reach.

Furthermore, long-term monitoring of the trial pads is anticipated to improve our understanding of the potential geotechnical, geochemical, and hydrologic benefits of commingled materials.

Speaker Biographies

Mind the Gap: Innovations in Geochemical Management

Dr. Heidi Cossey headshot

Dr. Heidi Cossey, PhD

Lead Presenter

Heidi has a PhD in Geoenvironmental Engineering and 10 years of graduate research and consulting experience related to the biogeochemical and geotechnical behavior of mine waste. She collaborates with industry and academic partners to design programs evaluating source control strategies for mine waste management facilities. She was awarded a Governor General’s Gold Medal in recognition of her doctoral research on the reclamation of oil sands tailings in pit lakes.

Kristin Salzsauler headshot

Kristin Salzsauler, MSc, PGeo

Co-Presenter

Kristin is a Senior Principal Geoscientist with over 20 years of experience in geochemical characterization of mine waste. Her expertise includes acid rock drainage (ARD), metal leaching, water quality prediction, and mine planning for geochemical risk mitigation. She leads studies on the geochemical and geotechnical behavior of mined materials and supports the design of mine waste management facilities. Kristin is known for building collaborative, multidisciplinary teams focused on minimizing long-term environmental impacts of mined materials.

Beyond GISTM – The Next Era in Safe Tailings Facilities

Scott Martens headshot

Scott Martens

Presenter

Scott Martens is the Director, Tailings and Geotechnical Engineering at Teck Resources, providing corporate oversight of tailings and mine waste management at Teck’s operating mines, development projects and legacy facilities across North and South America. Scott has 30 years of geotechnical engineering experience, half each in consulting and geotechnical mining operations. His focus has been on the design, construction and safety assessments of tailings and water dams. Scott has a Bachelor of Civil Engineering degree from the University of British Columbia and a Master’s degree in Geotechnical Engineering from the University of Alberta. Scott is an Adjunct Professor of Geotechnical Engineering at the University of Alberta, a member of an independent tailings review board, and the past chair of the Mining Dams Committee for the Canadian Dam Association.

GeoStable Trials – Exploring the Future of Commingling

Dennis Rugg headshot

Dennis Rugg

Lead Presenter

Dennis Rugg is Manager- Tailings Technology and Projects at Freeport-McMoRan and works in the corporate Tailings, Crushed Leach, and Water group. Mr. Rugg joined Freeport in 2020 and has focused his efforts on tailings storage facility expansion projects, including siting, alternative technology assessments, multiple accounts analyses, and engineering/design of preferred alternatives. Mr. Rugg leads Freeport’s Tailings Innovation Group, which comprises a multi-disciplinary team of engineers and specialists focused on evaluating alternative tailings technologies for new TSF projects and supporting Freeport’s operations teams to review existing TSF technologies. The group’s goal is to identify commercially viable technologies that may result in water savings, improved social and environmental aspects, and/or enhanced geotechnical characteristics for our TSFs. Dennis and his colleagues also represent Freeport on the GeoStable Tailings Consortium. Prior to Freeport, Mr. Rugg was a Senior Geotechnical Engineer and Associate with Golder Associates Inc. (WSP) where he focused on project delivery and team management for multi-disciplinary tailings, waste rock, and coal combustion residual design and construction projects. While at Golder, his projects included the application of thickened, paste and filtered tailings technologies to evaluate the preferred, most cost-effective, and environmentally friendly waste management solutions for clients around the world.

Tamara Butler Johndrow headshot

Tamara Butler Johndrow, MS, PE

Co-Presenter

Tamara Butler Johndrow is Director of Tailings, Crushed Leach, and Water at Freeport-McMoRan. She received her B.S and M.S. in Civil Engineering and is a licensed Professional Engineer with 27 years of experience in water resources and geotechnical engineering, management and program development. She began her career as a consultant at Golder Associates (WSP) and Engineering & Hydrosystems (WSP Golder). Ms. Johndrow joined Freeport-McMoRan in 2008, creating the Tailings, Crushed Leach, and Water team to support business critical areas of tailings storage facility, crushed leach stockpiles, and dam safety as well as water management across Freeport’s portfolio. Over the years, she’s had responsibilities for strategic planning, design, construction quality, operational support, inspection, review, governance processes and reporting, and due diligence for tailings storage facilities as well as crushed leach stockpiles, levees, water dams, and water management strategy. Today, Ms. Johndrow is focused on tailings and water governance, tailings innovation, and water management solutions. She is a trusted advisor to Freeport-McMoRan executive leaders, and she represents the company in various external tailings research and management engagements. She currently chairs the Tailings Management & Innovation Working Group for the International Council on Mining and Metals (ICMM) and the GeoStable Tailings Consortium Steering Committee.

Special Presentations – Tailings and Mine Waste Conference
Tailings and Mine Waste Conference Logo

Special Presentations

Tailings and Mine Waste Conference

Featured Presentations

Commingling Waste Rock and Tailings: Advancing the State-of-the-Art Practices in Mine Waste Management

Aniseh Dadashi, University of Alberta

Abstract:

The long-term management of mine waste presents ongoing challenges due to the risks of Acid Rock Drainage (ARD), geotechnical instability, and the growing volumes of tailings and waste rock that require storage. Commingling, the engineered blending of waste rock and tailings, has emerged as an alternative strategy that offers both geochemical and geotechnical benefits. Research has shown that fine-grained tailings can fill voids within the waste rock, reducing preferential flow paths and limiting oxygen ingress. At the same time, coarse waste rock particles improve structural stability by forming particle-to-particle contacts, thereby reducing the potential for liquefaction in the tailings.

This study reviews the evolution of commingling research and presents recent findings that strengthen its application. A key outcome illustrates the role of mixture ratio in balancing geotechnical and geochemical stability. Results indicate that optimized mixtures can control drainage and water retention, maintaining sufficient saturation while limiting oxygen flux. Oxygen testing confirmed reduced elemental release, directly linking mixture design to ARD control. In addition, Computerized Axial Tomography (CAT) scanning revealed the internal structure of commingled materials, showing tailings effectively filling the voids. These findings provide evidence of how commingling enhances mixture performance.

Toward a More Integrated View of Performance for Mine Waste Management Projects

Michel Julien, P.Eng., MSc, PhD, FEIC, FCAE, ASC

Abstract:

Over the past decade, the field of mine waste management has undergone significant transformation, leading to substantial improvements in industry practices and technical performance. While these advances have strengthened the sector’s approach to ensuring physical stability—long recognized as a central priority—it is now timely to adopt a broader and more integrated definition of performance and ultimately success for mine waste projects. Beyond geotechnical integrity, project performance should encompass a wider range of interrelated factors, including geochemical stability over both short- and long-term, water management, environmental aspects, social acceptability and closure planning.

Despite this broader understanding, these projects continue to be evaluated through cost and schedule. Given the recurring challenges related to budget overruns and delays observed across numerous projects in recent years, there is clear value in reinforcing cost and schedule as explicit performance indicators—while critically examining how they are defined and assessed. In particular, a more robust evaluation of the true costs of mine waste facilities and associated infrastructures, accounting for uncertainty and long-term obligations, is essential to achieving a more comprehensive and realistic picture of project performance.

Reimagining Mine Waste Management for Repurposing and Closure

David Williams, The University of Queensland, Brisbane, Australia

Abstract:

Mining operations focus on the production of a commodity, which is used in a multitude of applications, offsite, becoming someone else’s problem. However, mining and processing produces an ever-increasing volume of mining and processing wastes, particularly as the demand for commodities increases and ore grades diminish. The volume of the wastes dwarf the volume of the commodity extracted, and is typically stored on site, forever. Gold is mined down to one gram per tonne, producing vast quantities of waste rock and tailings, copper ores typically have a grade of around one percent, and so on. Hence, mining and processing operations are actually in the mine waste management business, which is not acknowledged.

Mine wastes need to be managed with repurposing, reprocessing and closure in mind. The presentation will describe potential mine waste repurposing and reprocessing, mine site repurposing, and closure to add value rather than just be a future accounting cost.

Speaker Biographies

Commingling Waste Rock and Tailings

Aniseh Dadashi headshot

Aniseh Dadashi

University of Alberta

Aniseh Dadashi is a Geotechnical Consultant in the Mine Waste team at WSP and a PhD Candidate in Civil and Environmental Engineering at the University of Alberta under the supervision of Dr. Ward Wilson. Her research focuses on the geotechnical and geochemical characterization of commingled waste rock and tailings, with the goal of developing innovative approaches to improve mine waste storage, mitigate Acid Rock Drainage, and enhance long-term stability. She has extensive experience in advanced laboratory testing and numerical modeling. In her role at WSP, she applies her academic expertise to practical mine closure and waste management projects. Her work bridges academic research and engineering practice, aiming to provide sustainable, cost-effective solutions for long-term mine waste management.

Toward a More Integrated View of Performance

Michel Julien headshot

Michel Julien, P.Eng., MSc, PhD, FEIC, FCAE, ASC

Vice-President, Environment and Critical Infrastructure, Agnico Eagle Mines Limited

Michel Julien is Vice-President, Environment and Critical Infrastructure for Agnico Eagle Mines Limited (AEM). He joined AEM in 2011. In his current role, he is providing guidance, mentoring and alignment on strategical issues on environmental management, mine waste and water management, and, site rehabilitation. Prior joining AEM, he was with Golder Associates Ltd (Golder) between 1990 and 2011 where he was Principal in the field of environmental management in mining. He has also been involved with University of Toronto since 2012 as Adjunct Professor in the Civil and Mineral Department. He has been co-responsible of the course Environmental Management in Mining since 2012. He has also been Director at Large on the Board of the Canadian Dam Association (CDA) (2021-2025). Over the years, he has authored or co-authored several articles, publications and presentations in the field of mine waste and water management. He is also a Fellow of the Engineering Institute of Canada and the Canadian Academy of Engineering.

Reimagining Mine Waste Management for Repurposing and Closure

David Williams headshot

David Williams

The University of Queensland, Brisbane, Australia

Dr David Williams is Emeritus Professor of Geotechnical Engineering within the School of Civil Engineering at The University of Queensland in Brisbane, Australia and continues to provide high-level consulting in tailings management and mine closure in Australia and globally. He has 50 years’ experience teaching and applying geotechnical principles to mine waste management, for which he enjoys an international reputation.

Tailings and Mine Waste Conference • Leading Innovation in Mine Waste Management