Over the past 40 years, we as a society have become more and more aware of the need to protect the environment where we can – an understandable concern considering the fact that damage done during the industrial revolution continues to impact our environment even now. In the environmentally conscious world we now live in, the mining industry is often cast as a villain, leaving contaminated resources and ravaged habitats in its wake. Not even the industry can deny that mining - especially as it was done in the past with few, if any regulations - can be destructive; leaving toxic and hazardous materials scattered around haphazardly is not the best way to secure the future for the generations to come.
What many people don’t realize, is that the mining industry has been making significant strides in mine closure processes that efficently and effectively return mines to either their former glory, or makes them habitable for some other purpose. Mine land reclamation and closure plans are being required by the ever increasing number of regulatory agencies around the world, and are often included in the environmental impact assessment process (practiced by over 100 countries) that are part of the consideration process to determine whether or not a company will be allowed to start operation. We may not be able to change the past, but the industry is changing the future.
The Closure Process
So how does this closure thing work? you may be asking. Mine site rehabilitation is now integrated into the early planning of a mine, often before any actual mining occurs, and is an ongoing consideration through the mine’s lifetime both financially and technically. Mine closure typically consists of several steps that can be efficiently executed with long-term planning:
- Shut-down: Once production comes to a halt, a small labor force is retained to permanently shut down the mining equipment.
- Decommissioning: The mining processing facilities and equipment are taken apart/decommissioned, pipelines drained, equipment parts cleaned and sold, buildings repurposed/demolished, warehouse materials recovered, and waste disposed of.
- Remediation/Reclamation: The land and watercourses are returned to an acceptable standard of productive use (landforms and structures are stable, watercourses have acceptable water quality). Reclamation typically involves removing hazardous materials, reshaping the land, restoring topsoil, and planting native grasses/trees/ground cover.
- Post-closure: The reclamation is monitored to assess the success of the process as well as identify any issues that need corrected. Some mines can require long-term care and maintenance after closure.
Lake on the site of the former Big Brown Mine in East Texas, now used for genetic research of large mouth bass.
Covering the Costs of Closure
The ups and downs of the mining industry can make the financial stability of companies tenuous, and in the past mining companies have been financially unable to finish the reclamation of a site due to unforeseen circumstances. For this reason, mining companies post reclamation bonds (or deposits) at the start of the project to guarantee that they can financially meet the requirements of safe closure. The bond amount can range from thousands of dollars to millions, depending on the size of the mine and the jurisdiction the mine is located in.
Different agencies have different requirements, even on a state by state basis in the U.S. For example, Texas determines financial assurance by the mine’s permit conditions, whereas Arkansas requires financial assurance covering the complete cost of the cleanup. Agencies around the world have a wide range of varied requirements, as well. Australia determines financial assurance on a case-by-case basis, while India requires a fixed sum per hectare.
While financial assurance programs are relatively new and have not been fully utilized by all jurisdictions, the reclamation process has been greatly improved by the requirements. The majority of officials surveyed in Canada, South Africa, and the U.S. reported that the financial assurance programs were generally effective.
Steps of a Mine Closure Plan
Closure plans are specific to each mine and include a detailed strategy of how the company will close the site, how environmental protection will be reached, and how the site will be returned to an acceptable state. The Four R’s represent the four distinct steps in preparing a site for another use.
- Remediation: Cleaning up contaminated areas by removing/isolating contaminants.
- Reclamation: Physically stabilizing the terrain, landscaping, restoring topsoil, and returning land to a useful purpose.
- Restoration: Rebuilding the ecosystem that existed at the site before it was disturbed.
- Rehabilitation: Establishing a stable/self-sustaining ecosystem (not necessarily one that existed before mining). Sometimes complete restoration is impossible, however a successful completion of all four steps can result in a functional ecosystem.
St. Kinga's Chapel, underground cathedral in the Wieliczka Salt Mine, Poland.
Potential Uses for After Closure
Many mine sites are returned to their pre-mine use (often wildlife habitat, forest, grasslands, etc.), however innovative new ways to repurpose abandoned mines both above and below ground are being thought of and implemented each year for mines that can't be completely restored to their pre-mine state. A trend is on the rise leaning toward the concept of economic sustainability, leading to some very creative new uses of decommissioned mine sites around the world. Repurposing abandoned sites is not only beneficial to the environment, it is also huge for local economies, especially areas that were hard hit by unemployment rates when mines were closed.
The economic contribution of taking advantage of existing infrastructure, plus the boost to the local economy has led to former mine sites being used as museums/educational centers (ex. Britannia Mine Museum, British Columbia), visitor attractions (ex. Wieliczka Salt Mine, Poland), scientific centers (Sanford Underground Research Facility, South Dakota), recreational areas (Gotland Ring, Sweden; Zip World, Wales), gardens or parks (Butchard Gardens, British Columbia), fish farms (AngloGold Ashanti Homase Mine, Ghana), data storage (Iron Mountain, Pennsylvania), agriculture (Big Brown Mine, Texas), golf courses (Armada Golf Club, Poland), and even underground theme parks (Salina Turda, Romania)!
The agency leading the charge for mine reclamation in the United States is the Office of Surface Mining Reclamation and Enforcement (OSMRE). Created in 1977 after Congress enacted the Surface Mining Control and Reclamation Act, OSMRE works to ensure that citizens and the environment of the U.S. are protected during mining and that the land is restored once the mining is finished. Since OSMRE's inception, more than 2.8 million acres of mined lands have been restored to beneficial use by mining companies – including more than 100,000 acres of coal mines abandoned long ago. It's not a fast or simple process - worthwhile endeavors rarely are - but the results and future impact make it worth it!