By Holly Krutka
Executive Editor, Cornerstone
Responsible Editor, Cornerstone
The process of reclamation of mining lands includes many important considerations and is often far from simple. However, practices related to reclamation have improved significantly in recent years. Although the primary purpose of a mine reclamation plan is usually to minimize the impact to the local environment after a mine is closed, today’s mine reclamation plans can encompass much more than just returning a mining site to its natural state. In fact, some closed mines are now forests, farmlands, open spaces, or public parks. In the history of mining operations, there have been too many examples of mining lands that were not properly cared for and, of course, such instances have garnered much publicity. Today, practices are changing and, in many countries, mining permits will not be granted without a complete mine closure plan with the funding secured to support the plan. This article highlights the strategy, options, and select success stories from mining sites that were reclaimed properly.
Using best practices to reclaim mining lands after a mine has been closed comes at a cost—an estimated US$1.5 million per mine.1 The way this money is spent is based, in part, on how the land will be used, which is often determined after consultation with the local government, NGOs, land owners, and others. The steps for the land reclamation process can include: 1
- Landscape maintenance and design (e.g., map predicting topography, backfill as necessary, examination of drainage)
- Management and restructuring of overburden and soil (e.g., ensuring slope stability)
- Backfilling: Necessary in deep mines to avoid collapse and in surface mines to promote safety and create a smooth landscape
- Topsoil management
- Management and reuse of waste materials
After these steps are taken, the ecosystem can be rebuilt, either actively or passively. The case studies presented here highlight several examples of how ecosystems were rebuilt, which can be contingent on the type of land use intended.
Options for Mine Reclamation
Several options are available for uses for reclaimed mining sites; the selection for the land usage must be based on economic considerations, location, societal needs, and the local ecosystem. There are economic uses for the land (e.g., industry or housing) as well as productive uses (cultivation, grazing, fishing, parking, etc.). In some cases, it could also be appropriate to open the reclaimed mine site to community use, such as a public park, nature conservancy, etc. The optimal use of closed mining sites must be based on the needs of the local community. For example, in the European Union over 50% of mining lands that have been reclaimed are used for forests or grasslands. However, in China, where there is a shortage of farmland, over 70% of reclaimed mining lands are used for agricultural purposes.2 In most cases worldwide, reclaimed mining sites are converted into lands suitable for forestry or agriculture.
Case Studies of Reclaimed Mines
Ereen Mine, Mongolia
The Peabody Energy Ereen mining site, located on the remote northern slopes of Mongolia, was acquired by Peabody Energy through a joint venture in 2009. However, the mine was shut down soon after it was acquired. To carry out the mine closure and land reclamation plan, the mine owners allotted the resources to support 60 personnel, including a key choice for leading the closure and reclamation effort, Vern Pfannenstiel, who had extensive experience with mine closure and land reclamation. The most relevant example of his work experience related to his involvement with restoration projects on the Black Mesa (Arizona, U.S.), where he also dealt with a remote location and the need to work with the indigenous people.
In addition to the usual issues that come with mine closure and land reclamation, the remoteness of the Ereen site posed unique challenges. For example, workers had to camp at the site. Without the necessary specialized seeding equipment available locally, such equipment had to be shipped from the U.S., which required five months. The US$1 million project transformed the former mine site into 44 acres of grassland, which is now used as pastureland for traditional livestock grazing. The project also provided a source of fresh drinking water in an area that did not previously have easy access to potable water.
Peabody Energy carried out the restoration with the nomadic community’s cultural practices and land uses in mind. The new community well separates drinking water from livestock water, protecting the purity of water intended for human consumption. The design took into account the harsh conditions typical in Mongolia. The restored landscape also incorporates a surface pond where local herders can bring their cattle, goats, horses, and sheep to drink.
Fencing protects the reclamation area from free-roaming livestock during the establishment phase of the project. Recent monitoring indicates that, with foliage production running at four times that of native lands, the site has strong potential as a hay production resource, critical for feeding local livestock during the harsh winter. All the project’s camp supplies, construction materials, and parts were purchased locally or through established manufacturers with branch offices in Mongolia. As well as transferring technical knowledge to the local workforce, Peabody Energy donated materials, supplies, and housing from the project back to the local governments and herders, and employed local families as caretakers. Two local families, one of which has grazed its herds at Ereen for generations, accepted responsibility for ongoing site maintenance and management. Another family took custodianship of the well, and keeps the upstream watershed free from potential contaminants.
Huehnerwasser Catchment at Welzow-South Coal Mine, Germany
A truly unique reclamation project is underway near Cottbus, State of Brandenburg, Germany, at a location called Huehnerwasser (Chicken Creek), where there was previously an open pit mine. This site is owned by the Swedish mining company Vattenfall Europe Mining AG, which is producing lignite in the region and is also responsible for restoration. While the reclamation project was closely watched and monitored, the ecosystem was left to develop itself. This gives researchers a rare opportunity to observe and monitor a fledgling ecosystem.
In 2005, the first steps of the project, which spans approximately six football fields, were to deposit regional sediment, complete grading, and then fence it off. A local groundwater body was allowed to establish on top of a clay layer. After these steps, a relatively minimalist approach was taken.3Although the area was observed closely, no seeds were planted and no other active steps were taken to encourage plant growth. Then researchers from the Brandenburg University of Technology Cottbus, Technische Universitaet Muenchen, and other institutions were allowed to closely monitor the site. Many diverse groups share this research site in a collaborative effort: For example, plant ecologists closely watch which plants are able to take hold and the order in which plants grow; forestry researchers and soil ecologists watch for changes in the soil. Scientists are studying the influence of several key factors on ecosystem development. Over 70 papers have been published by the collaborative research center to date. The research group has also established a website (www.tu-cottbus.de/projekte /en/ oekosysteme) where webcams can be viewed by the public.
The project is set to run for 12 years, which is relatively short as far as ecosystem development is concerned. The results from this project could hold discoveries not only valuable to the scientific community, but also to the mining industries on how best to encourage the return of closed mines to a natural state.
Northumberlandia, Newcastle, England
Northumberlandia is another truly unusual example of how mining operations and public use of land can go hand in hand. This project was completed in 2012 in the area of Cramlington, Northumberland, in northern England. Actually, Northumberlandia is considered a restoration-first project, wherein mining operations are ongoing while an extra piece of land near the mine was converted to a large public park, partly using material excavated from the mine. The cost of the project was £3 million (double the average costs for a mine reclamation project); both the creation of the park and its maintenance are privately funded by the Banks Mining Group and the Blagdon Estates. The park is open to the public free of charge.
The park was designed by landscape architect Charles Jencks; his vision was to create a park in the shape of a nude woman. The park includes four miles of footpaths in a 47-acre park.
Hunlunbeier, Inner Mongolia, China
Hunlunbeier is located in northeastern Inner Mongolia in China. This area has rich coal reserves, estimated at more than 100 billion tons. The region is also the largest natural grassland in the world, and is characterized by a harsh winter climate and weak surface ecology. The Baorixile coal mine, owned and operated by the Shenhua Group, is located in the region and currently produces over 30 million tons coal per year. The grasslands are somewhat delicate; for this reason it is important that care is taken during the reclamation process, which is ongoing and carried out simultaneously with mining.
For this site three main steps are employed for the ongoing reclamation: stripping the topsoil prior to mining, stacking and dumping the fill into the open pits, and beautification. Before any mining is begun, surface soil is stripped and stored for future use. The humus soil, which is 0.3–0.5 meters below the surface, is particularly important for supporting plant life. After mining at a particular location is complete, the stripped earth is stacked layer by layer and dumped into the open pits in a stepwise manner. The earth is dumped into the open pits in the largest possible quantities immediately after mining, which limits the amount of stripped earth on the grassland. Finally, the last step of the reclamation process includes beautification of the site, which mainly consists of introducing the appropriate ecology.
Of course, the angle at which the land is recomposed is important to mitigate the risk of collapse. For the Shenhua Baorixile site, a hydraulic excavator and forklift were used to form the wastepile into a series of steps with a 35° angle. The angle of this particular site was selected to limit wastepile height as well as to ensure stability. After the shape of the wastepile was selected, the stored humus soil was spread over the wastepile. Finally, grass seed was sown, and plants began to grow.
The Shenhua Group continues to monitor the many reclamation sites in this area and work on them as needed. The backfill and plant work are ongoing as the amount of reclaimed land increases and additional grass and trees are added as necessary. Today, the reclaimed land is used for growing fruit and vegetable crops, which provide an additional source of income to the local community.
From 2006 to 2012, the Shenhua Group invested more than 112 million RMB (~US$18.7 million) to reclaim mining sites throughout the Baorixile coal mine area. To date, the reclaimed land covers more than 3,850,000 m2 (nearly 1000 acres). From 2012 to 2014, Shenhua Group expects to invest another 150 million RMB (US$25 million) on continued reclamation.
A successfully reclaimed mining site can be valuable to a community long after mining operations have ceased. Several examples have been provided of successfully reclaimed lands; the final results for these projects included much needed grazing land, a unique park, a research project, and agriculture. Reclaimed mines can benefit the economy and the ecology of the local community if the reclamation process is carried out in a responsible manner.
- L. Sloss, Coal Mine Site Reclamation CCC/216, Published online by the IEA Clean Coal Centre, February 2013, Available at bookshop.iea-coal.org.uk
- X. Bian, H.I. Inyang, J.L. Daniels, F.J.L., Otto, F., Struthers, S. Environmental Issues from Coal Mining and Their Solutions, Mining Science and Technology, 2010, 20 (2), 215–223.
- Elmer, M., Gerwin, W., Schaaf, W., Zaplata, M., Hohberg, K., Nenov, R., Bens, O., Huttl, R. Dynamics of Initial Ecosystem Development at the Artificial Catchment Chicken Creek, Lusatia, Germany, Environ. Earth Sci., 2013, 69, 491–505.