Reclamation planning: Q & A

Catherine Hercus | July 31, 2024 | 2:41 pm

The importance of a holistic approach to reclamation planning using monitoring with the flexibility to pivot when necessary are some of the themes discussed with Sara Wilkins from Stantec and Megan Miller from SRK Consulting.

Sara Wilkins is the global mine water practice lead at Stantec, specializing in mine water management and groundwater and surface water assessments. She has an environmental sciences background and 20 years of experience in mine closure and reclamation. Wilkins holds a P.Geo. designation and has a B.Sc. in environmental geology from Carleton University.

Megan Miller is a principal consultant at SRK Consulting. She has 15 years of experience in reclamation, mine closure, and permitting. Miller has an M.Sc. in civil engineering from the University of British Columbia.

Q: At what point in the life cycle of a mine is the reclamation plan put together?

A: Sara Wilkins: When the mine is either acquired or developed by the operator. We see reclamation planning on a holistic level. You are not just planning for closure; you are proactively managing your assets. You are looking at each one of your assets as potential value back to the land or back to the community. And every time that you do a good job, in informing and involving the community, you have an easier and a more beneficial relationship with that community, and it allows for you to plan better and integrate them into your plan.

Q: Is there any typical reclamation plan or are they site-specific?

A: Sara Wilkins: Stantec has an integrated mine closure team, including mine planners, environmental planners, and water planners. What we can do with that one team is understand all components that we need to consider before we design the mine.

Land use planning allows for potential uses such as compensation lakes, which are kilometers wide. You need to save or develop the landscape to create the water, the drainage system, and ecological system to sustain that lake into closure. If you do not integrate that into your mine plan, you will not have that option.

When you are planning your mine, you must understand what resources are available. Are you in the Arctic? Are you in the desert? What is available for site reclamation purposes?

Megan Miller: It depends on the project, we work with tech experts, geochemists, hydro, water and load balance, engineers, and water treatment specialists. Sometimes we collaborate with company employees on site, or we work with external or other consultants. We have a partnership with an ecology company working on revegetation, which is soil for growing things.

Q: Are there any specific approaches that you use?

A: Sara Wilkins: It is very important to do progressive reclamation. This entails managing the soil and reclamation program on a monthly and annual basis, so that we can stock topsoil and seed bank. Then, we do not have to start introducing nonnative plants at closure or spend extra money to import and find topsoil instead of stockpiling it properly at the start.

As we are monitoring your reclamation progress, we can do something called “adaptive management,” where we reclaim a certain area. This helps you understand what is growing there, and how productive that area is.

I think it is important that geochemistry, water, and land use planning are done in an integrated fashion. We do not simply look at what kind of plants you can plant at closure. How do we avoid water contamination at closure? How do we create a landscape that is going to be low risk? You look at what type of entire ecosystem can be created and use modeling to predict if you can get there.

We can avoid a lot of risks by investing early in planning and monitoring water quality and assessing the geochemistry coming out of waste rock piles or any facilities that have been closed. We can develop techniques and use that knowledge to modify or quickly avoid problems, even if we have to change the mine plan. We can change our mining methods and reclamation techniques to reduce those risks.

We are in a better position to monitor activities and make changes more cost effectively before the mine is closed. When the mine starts to shut down, we do not have the on-site experts and resources available. Then, at closure, we can model and come up with novel techniques to avoid a lot of the contamination that that many legacy sites are experiencing.

Megan Miller: My philosophy is to try to make it a practical plan looking at an integrated, holistic approach. The main thing to consider is what to do with the water. That drives everything. Often, there is an erosion problem. It really comes down to the specific sites. We use vegetation to stop erosion. We find the best plan to make that happen. We put the topsoil in a pile at the beginning, and if there is not enough topsoil, it must be borrowed. Then, we consider what are the best sources to grow, and how to place it.

Q: What are some of the challenges?

A: Sara Wilkins: I have been doing this for 20 years, and every single site consistently runs out of topsoil. The deficit of topsoil leads to problems because we cannot create that native seed bank that was there when the mine was first built.

If you try to import nonnative plants, you end up having invasive species. If you try to create an ecological site at closure that is different from what was previously there, by not properly planning and managing your topsoil, it will be a lot more expensive.

Megan Miller: One of the challenges in northern sites includes permafrost. We must consider how we deal with disturbing new ground and borrowing soil that is not thawed when it needs to be.

Q: Is it easier to do reclamation for underground mines as opposed to open pit ones?

A: Sara Wilkins: There is less of a surface disturbance in an underground mine. There is also less visible impact on the mine, but it is not necessarily easier. It just leads to a smaller area of land that we need to reclaim, and there is a smaller surface footprint. There is still a surface footprint from the facilities, but we are going to have less of a visible ecosystem or visible landscape to then reclaim.

Megan Miller: Underground mines have less waste rock. In open pits, we need a place to store the water, as we do not have a built-in containment area.

Q: What type of monitoring do you do?

A: Sara Wilkins: It is site-specific but also dependent on how well the mine is managed to reduce a lot of long-term problems through monitoring. Stantec uses some proprietary and industry tools using remote sensing to monitor.

Although it might take resources, we can reduce the amount of people on the land, so they do not have to be at the site physically any longer than they need to be. If most of the earthwork is completed, then we can use remote sensing tools for monitoring program. We can use technology such as Environmental DNA (eDNA), which monitors different species in the water from a water sample. We can observe if nonnative invasive species or species we did not plan for are in those waters by taking a quick water sample without having to do a very large invasive fish capture program.

We also can fly over the mine or purchase satellite imagery technology. In just one data capture event, we can monitor the lands reclamation progress. We can monitor tree growth, wind, and waiver erosion, the stability of tailings, dam faces, carbon capture ability, and the geotechnical stability of the land remotely.

We utilize artificial intelligence (AI) because the processes accumulate large amounts of data with a low-impact data collection system.

Closure can be done in a low-impact way, and we can also keep our commitment to the local communities to reduce any disturbance because we are not physically there. And that also brings in safety benefits as we are not sending people out in the middle of a lake on a boat in the Arctic, reducing impact from a cost and a people standpoint.

We have a lot of partnerships and formal partnerships with technology partners that support us.

We also have a large team of in-house developers and software managers that help us build these tools. Stantec dot IO is our information technology group, and the remote sensing group is called GLOBEWATCH.

We use several models, including geochemistry and water models, which can predict the outcomes at closure and modify mine plans accordingly. The last thing we need at closure is to bring everybody back and start changing the existing processes.

Megan Miller: We use commercial software for monitoring including all the data on water quality and temperature readings. Dashboards work in real time, and the database is used for visualization.

Q: Is remediation a part of reclamation as well, or is that different?

A: Sara Wilkins: Remediation would be the final last resort. Ideally, we are using avoidance techniques and trying to avoid having to remediate by planning properly. Remediation is, in my view, for more of an emergency. For example, if we had a spill. Ideally, we are not remediating, we are simply closing and managing to reduce any impacts.

Q: How long does reclamation take at a site?

A: Sara Wilkins: Typically, we would not be doing active reclamation for more than a few years after the mine has closed. The monitoring can be ongoing, and we can do adaptive management during mining to hopefully not find any surprises while you continue to monitor, but the process itself is not that long once the mine is closed.

Megan Miller: Regarding water treatment, ideally, we do not need to do this long term. On historic sites, we collect water seasonally when it is discharged. For example, it is low flowing in winter, and we need to store the water in the meantime.

Q: Are there opportunities for the local community to be involved in reclamation activities?

A: Sara Wilkins: Stantec has 13 formal partnerships where they are a minority stakeholder in a business relationship with Indigenous communities, and we work with those companies, including training programs, and we hire them as part of our field or engineering teams.

There is a strong willingness for them to be involved because the mine can ruin the land. We need to be good stewards of the land. Once they are involved, invested, and have local employment, now we are partners.

Megan Miller: Regarding consulting communities on land use and how it will be used, I am not on the frontline speaking to them. I have attended community meetings, presented a range of options, and received input from the attendees. Project information goes to a review committee and a panel presents the information, and then we take the feedback we received into consideration. CMJ

Catherine Hercus is a freelance writer.