Reinventing mine closure: Creating assets for the future
June 17, 2024
When a mine closes, its life doesn¡¯t have to end. It can be repurposed for a variety of other needs. Here¡¯s how.
In the last few decades, we have been seeing a reinvention of mine closure. Mine owners can¡¯t simply walk away from a mine site anymore. Now, they are valuing natural capital and using nature-based solutions to not only close mines so they adhere to regulatory standards, but also to transform the site into a useful asset. This is a win-win-win scenario for our clients, our communities, and the environment. But it also helps mining operators gain or maintain the social license to operate.
Communities want mine operators to be strong environmental stewards. After all, they live in the region. They want clean air, soil, and water for their friends and families. They are important stakeholders who understand local needs. Beyond the environmental factors, key considerations include access to power production, jobs for residents, and transportation infrastructure as mines are often in remote communities. But those needs don¡¯t end once a mine¡¯s life does. In fact, a community can benefit from a mine site long after operations have ceased.
That¡¯s why closure plans are so integral in planning for a mine site. A mine¡¯s life doesn¡¯t end after extracting minerals and metals¡ªthe site can be transformed for many beneficial uses after closure. Today, a mine must have a closure plan in place before it can even be built. And we see many mining companies actively engaging in the community long after the mine closed.
Modern approaches to mine closure lead to creative transformations. From recreation, redevelopment, renewable energy production, or returning the land to its original owners, old mine sites can get a second life. So, let¡¯s explore how to transform a mine and yield multiple benefits for our clients, our communities, and the environment.
By planning for mine closure early in the process, we can not only help the environment but the local communities who can still benefit from the site long after mining operations have ceased.
A community asset: Repurposing your mine site to benefit the community
One of our favorite ways to plan for mine closure? Imagining all the purposes the community can use a site for after its operations have ceased. As engineers, we always have thoughts of our own. But we love hearing from community stakeholders on what they want or what they need. As you can imagine, results vary!
Recreational space can have a profound positive impact on a community. Right now, we are working on the Pikeview Quarry Reclamation Project in Colorado. The goal of this project? To transform a closed limestone mine into a community asset. The mine officially closed in 2018 and has since been seen as a scar to the local community¡ªeven though much of the mined materials went directly into building the town of Colorado Springs!
Our teams have been working to repurpose the site into something positive. We started by reclaiming the site to establish a safe and sustainable environment conducive to both human and wildlife activities. Next was restoration, where our teams embarked on planting more than 31,000 native plants and trees. This will produce a favorable ecosystem for wildlife like bighorn sheep, deer, bears, bobcats, fox, rabbits, and birds. But the story doesn¡¯t stop there.
After the restoration process, the City plans to make the site public for recreational use. Potential plans include constructing a mountain bike park, a recreation center, hiking trails, and a dog park.?Talk about an ¡°everyone wins¡± scenario! By designing the reclaimed land to be used as a local community resource, we not only helped our client remove the visible scar from Pikeview but created a space for residents to enjoy hikes, nature, and recreational activities.
Pikeview Quarry is an excellent example of a successful mine closure. It demonstrates innovation, originality, and creative engineering design. It also shows leadership from the mining industry as we strive towards sustainability and environmental stewardship.
Right now, we are working on the Pikeview Quarry Reclamation Project in Colorado. The goal of this project? To transform a closed limestone mine into a community asset.
Repurposing mine infrastructure to support communities
Most mines, especially those in remote regions, build infrastructure to support hundreds or thousands of workers needed to operate a mine site. This infrastructure includes things like housing, power, or logistics (air strips), and can almost be like a small town. This infrastructure can continue to be used to support post-mining development such as a new highway system, training facility, or commercial industrial use.
Repurposing can also include renewable energy generation such as solar, wind, or pumped storage hydropower. For example, once areas like tailings storage facilities and waste-rock landforms have been stabilised, the land can be used as a location for solar and wind generation. The benefit of existing construction access¡ªand already having high-capacity power lines to these remote locations¡ªmakes renewables a great fit here. There is a neat example of a former coal mine site being developed into the Nanticoke Solar Facility in Ontario.
A mine¡¯s life doesn¡¯t end after extracting minerals and metals¡ªthe site can be transformed for many beneficial uses after closure.
For open pit mines, we can explore pumped storage facilities. Pumped storage is the largest and most reliable form of renewable energy storage available. It consists of an upper and lower reservoir. When power demand is low, water is pumped from the lower reservoir to the upper reservoir and stored until power is needed. When the power is needed, it is released to the lower reservoir, generating energy like traditional hydropower facilities.?
The?South Middleback Ranges Pumped Hydro?project is currently considering pumped storage at an iron ore mine that is approaching the end of its economical life. This project is supported by funding from the South Australian Renewable Technology Fund and the Australian Renewable Energy Agency. The prefeasibility study looked at the concept of using the mine pit as a lower storage reservoir of a pumped storage facility.?
The scientific community can also benefit from the unique opportunities offered by closed underground mines. Initial concepts for what is now the?at the former Homestake Gold Mine in Lead, South Dakota, began while mining was still active. This research facility is now home to many physics, engineering, and geology studies, truly writing a new chapter in the life of the mine and the region.
If we have the end of a mining operation in mind, we can take proactive measures during the life of the mine. This can make the closure, and post-closure transition, easier. Transforming a closed site into a new asset can create long-standing jobs and makes use of land that¡¯s already been disturbed. In other words, we are transitioning the use of the land for thoughtful purposes while also maintaining economic drivers in the region.
For open pit mines, we can explore building pumped storage facilities.
A wild habitat: Returning land to a natural state
If a mine site is not suitable for a community recreation center or a renewable energy project, a simple option is to restore the land to its natural state. While today¡¯s regulations require any new mine to have a closure plan in place before they even begin mining, that wasn¡¯t always the case. In fact, we constantly work on abandoned or historic sites that are polluting the environment decades after the mine ceased operations.
We can lead by example in sustainable water management by restoring mining-impacted streams, wetlands, and woodlands to natural ecosystems. This means not just treating chemically-imbalanced water or mitigating acid rock drainage, but instead increasing the natural capital of the damaged ecosystem.
This stream restoration approach promotes biodiversity. And it helps companies get regulatory and social approval. Restoring a natural water system using nature-based solutions provides habitat for creatures living on land and in the water. Mine water management regulations in the US, for example, were historically based on preventing erosion. As a result, waterways often included hard armoring of the channel. These regulations deterred mine owners from pursuing stream restoration, since erosion is critical to natural streams. Thankfully, we¡¯re seeing many more mine closure plans that value natural capital.
Similarly to aquatic life, restoring a closed mine site can and should go beyond considering physical stability and grading. Topsoil is a key component of closure, as is vegetation. Choose a diverse seed and plant mixture that mimics the nearby natural setting. Opt for native plants, as invasive species will wreak havoc on natural systems. The cost of revegetating a closed mine is small compared to the other costs of closure and will help a mining company¡¯s public perception. For example, we recently supported a collaborative project at a mining waste rock site to create functional habitat for Caribou¡ªa species at risk in British Columbia.?
If a mine site is not suitable for a community recreation center or a renewable energy project, a simple option is to restore the land to its natural state.
An old mine site with a new lease on life
We need mining. Not only for our modern way of living, but also for our needs of the future. Mining for critical minerals and metals supports the energy transition and the use of renewable energy sources, electrification, grid modernization, electric vehicles, and more.
But we also need to mine sustainably. By planning for mine closure early in the process, we can not only help the environment but the local communities who can still benefit from the site long after mining operations have ceased. Whether repurposing a mine site for recreational uses, renewable energy generation, scientific research, or restoring the natural system, mine operators can be responsible stewards of the environment. This will aid us in leaving a cleaner¡ªand more productive¡ªplanet for future generations.