Planning for closure: Q & A

Ljililana Josic and Tim Joseph were interviewed on the topic of mine closure.

Ljiljana Josic is the senior director, tailings, water, and geotechnical engineering at AtkinsRéalis (formerly SNC-Lavalin) and has an M.E.Sc. degree in geotechnical/environmental engineering from Western University. She has over 25 years of experience in geo-environmental engineering, including geotechnical, environmental and hydrogeology. Her work has included dam design, design of tailings, waste rock, and sludge facilities on over 50 projects.
Ljiliana answered the following questions:

Q When should the closure plan be put in place?

A The closure plan should be discussed and initiated at an
early stage of the project. At the scoping level, different technologies for the tailings management should be evaluated and the best option should be selected based on selection criteria that include, social-economic, environmental, technical, and project economics. Closure of the facility definitively should be included in the tailing management design options evaluation criteria. The input from the community regarding post-mining is very important for developing the closure plan.

Designing for the closure using the best design practices is currently adopted by many mining operations. The closure plan is usually initiated at the pre-feasibility stage of the project and updated during mine operation. An early closure plan is very important to understand the cost of the closure. Financial provisioning and estimation can commence at the conceptual closure planning stage and should be updated every three to five years during the operation phase of the project.

Q How long will the closure plan take to be implemented?

A The tailings storage facilities are unique structures
designed for the specific environment, region, climate, ore type, geotechnical, physical, chemical properties, etc. The closure plan should ensure that tailings disposal area is left after operation as structurally stable, be resistant to deterioration through erosion, and be compatible with surrounding unmined landform. The closure plan implementation depends on the type of the tailing’s facility. For example, for the dry stack tailings, the closure can start earlier as a progressive reclamation.

Tailings dams are more difficult to close. Designing and planning for the closure during operation should ensure that the final state of the tailings mass will have high resistance to liquefaction and low risk of catastrophic failure. The tailings storage facility is closed when tailings deposition has ceased, and all closure activities have been completed.

Q Once the project enters closure and post-closure, water
management and treatment can become the dominant carbon generator. What can be done to mitigate this?

A To mitigate carbon generation in water management and
treatment during project closure and post-closure, several solutions can be implemented. Early incorporation of mine waste management in planning and design stages, along with the implementation of passive treatment systems like wetlands, can significantly reduce long-term maintenance needs and environmental liabilities.

Additionally, water recovery and tailings dam footprints can be maximized and minimized, respectively, through high-performance filters, achieving up to 90% water recovery, and utilizing compact and efficient designs that can reduce plant footprint substantially.

Further improvements can be achieved by enhancing filtration efficiency with technologies that separate fine and coarse streams, and by reducing reagent usage through the application of thickeners. These measures not only address environmental concerns but also enhance operational efficiency and sustainability in the long term.

Q What should happen after the mine is closed?

A While in the past, mine closure and reclamation may have
often been an afterthought, modern guidelines and legislation require closure plans and financial assurance to be initiated from the earliest stages of mine development. Closure plans and financial assurance requirements are typically developed based on the removal of mine facilities and rehabilitation of landforms to a condition similar to the pre-mining conditions and surrounding natural landscapes.

Reclamation and closure plan requirements vary by jurisdiction, but typical elements include provisions for temporary as well as permanent closure, with consideration of all elements of the mine. Of particular importance is the physical stability of open pits, tailings disposal facilities, and waste rock piles. The closure plan must demonstrate that these structures are stable in the long-term regarding slope stability as well as geochemical stability.

Closure plans will generally include monitoring plans for the post-closure period (i.e., active closure) to ensure that the intent of the closure plan is met. Full passive closure (i.e., the walk away scenario) can only occur once monitoring in the active care phase has demonstrated that remaining structures are physically stable and environmental requirements are met over an extended period.

Tim Joseph holds a Ph.D. in mining engineering from the
University of Alberta and the P. Eng., and FCIM designations.
He is the president and CEO of JPI Mine Equipment and Engineering. He is a mining operations’ consultant, and his company provides mining operations, performance, and engineering solutions, as well as mining courses. He is also a professor emeritus in mining engineering at the University of Alberta and has been part of the faculty of engineering for 21 years.
Tim answered the next two questions.

Q How important is engaging the local community in the
closure process?

A People talk about consultation. I do not think they really
understand what consultation needs to be, and it is not about just informing a community group and it does not matter whether it is a community, or whether it is Indigenous or not. It is just bad informing, saying we plan to do this just so you are aware.

How can you properly or more appropriately engage local communities so that at the point that the mine basically ceases to exist as an operating functional entity and they need to start implementing the closure, you need to make sure you leave the land as you found it.

The question really should be “how can we better engage the community at all stages, so they become part of the process, the workforce, and the group that gets training, information, and education out of that whole activity? At the end of mining, it is that community that becomes the custodian of the landscape and the water and the air and everything else.

So, the biggest conversation that comes up is when a community expresses concerns that if an exploration route comes into their area, it will taint their water and destroy the water quality. The companies are prepared to ensure that that water quality is maintained. Why not train the local people on how to maintain that water quality?

An exploration mission into an area can take five to 10 years before we even see a mine develop. So, that is years of activity when a community could be doing something. And you are giving self respect to the community members who are now actually working to support themselves. That is really the big win that I have seen in other countries where communities have become self-sustaining. They can do it themselves, and if the resources are attributed to the community, the community then pays taxation on those resources to the government.

Q What are some of the opportunities available after closure?

A This is a beef I have had for many, many years. What are
the opportunities for using the waste materials and does the waste have other uses other than just being waste? Are there products in there? I had an interesting conversation with a mineral processing designer in the uranium industry in Saskatoon recently. He said he really wants to write a paper next year about all the critical minerals that are missed that go out with the waste when they mine for uranium.

Companies mining oil sands are throwing titanium, vanadium, and other very valuable minerals away with the tailings. But processing that waste material can become an industry for the community beyond the mine as it stands today. Could the waste materials become the next generation of industry and employment for that community? Are there construction materials that can be utilized? We have seen this in Greece and Morocco where communities have latched onto the value of the waste materials, and they have used it to build roads in their region, and they became the go to road builder.

People are not thinking broadly enough about what the opportunities are in closure. We need to shut things down, green things up, and walk away. That is not the answer. I think the answer is what is the opportunity to make the community sustainable beyond the mining.

Particularly if it is a 20- to 30-year mine life and a whole generation will grow up knowing nothing else but mining. Otherwise, when the mine closes, the community dies.

More recently, they are all tied together because if we want to reduce emissions, there is a dollar value that you can sell to a mining company to say this is the value you will get. Do not just think in terms of dollars, think in terms of emissions reductions. If they could save hundreds of thousands of tonnes of CO₂, does that not have value?

How do you put a dollar value to that? Companies get stuck there. So, they say this is just something we have been asked to do. They are expected to reduce emissions by the province as part of the closure requirement and as part of the operating requirement, but they struggle to find that dollar incentive to say yes, we really need to pay attention to this. CMJ

Catherine Hercus is a freelance technical writer.