In mine closure planning, you frequently hear the three terms: rehabilitation, reclamation, and remediation. These terms are often used interchangeably but actually have different meanings. For this discussion, we will use the following definitions from Alberta Environment (2002):
Often a mine site will require features of all three in its closure plan. Understanding when and how each approach should be applied helps to minimize closure costs and add value to the returning land use.
Rehabilitation (sometimes colloquially referred to as Rehab) is the most common term used when referring to returning a mine site to a similar ecological state and/or function to that prior to disturbance. Rebuilding the ecosystem that existed at the mine site prior to disturbance is not possible in many cases, but a functional ecosystem can be established with successful reclamation and, where required, remediation (Yeldell and Squires, 2016). When developing rehabilitation options, a key focus area is the soil-plant-atmosphere interface that informs effective revegetation plans.
When vegetation characteristics are evaluated in conjunction with cover material physical properties, cover system depths can often be optimized to reduce borrow material requirements and associated haulage costs. Successful rehabilitation requires a clear understanding of landform and cover system requirements to support both resilient revegetation and locally native habitat for wildlife. A critical component of rehabilitation is long-term monitoring to ensure that the developed ecosystem is meeting the site-specific closure objectives through time and climate change scenarios.
A key component of mine closure is progressive rehabilitation involving the staged treatment of disturbed areas during exploration, construction, development, and mining operations. Treatment begins as soon as these areas become available, rather than undertaking large scale rehabilitation works at the end of mining activities (Yeldell and Squires, 2016). Mine closure planning can fully integrate progressive rehabilitation that is consistent with closure and post-closure land use objectives into daily mining operations. This ensures materials and resources are available to undertake the work required, including:
Reclamation is a term used during mine closure planning that offers more flexibility when discussing returning land use alternatives. The definition of successful reclamation is the physical stabilization of the terrain, landscaping, restoring topsoil, and the return of the land to a useful purpose. Mine site reclamation at minimum requires physical stabilization of tailings dams and waste rock piles (Yeldell and Squires, 2016). Post-closure land use options could include agriculture or new industrial uses in addition to the more traditional forestry or conservation options. Integrating long-term socio-economic, cultural, and ecological considerations into mine planning and closure planning processes ensures that a site’s reclamation plan can stay adaptable to current and future needs.
Remediation is more commonly used when referring to the management of potential hazards or constituents of concern. Remediation is the cleanup of the contaminated area to safe levels by removing or isolating contaminants. Remediation at mine sites often consists of isolating contaminated material in pre-existing tailings storage facilities, capping tailings and waste rock piles with clean topsoil, and collecting and treating any contaminated mine water if necessary (Yeldell and Squires, 2016).
When developing a remediation plan for a mine site, most jurisdictions require site characterizations that include an environmental and human health risk assessment. Regardless of the contaminant type or distribution, remediation plans need to address the transport pathways as well as exposure pathways and receptors.
Cover systems and landform designs can be excellent tools in site remediation and hazard management. Managing water and oxygen in mine rock stockpiles and pit lakes can not only manage solute balance, but also create opportunities for bioremediation. Saturated Rock Fills are an example of a passive water treatment bioremediation option for some mine sites where a hospitable environment is created for naturally occurring microbes that can remove selenium and nitrate.
The right approach to preparing a landform for returning land use depends on the site’s closure vision and objectives. In most cases, sites will require a combination approach to closure that includes rehabilitation, reclamation, and remediation.
When developing rehabilitation plans, Okane methodically works to develop a plan for self-sustaining, locally native revegetation and manageable long-term monitoring plans that will achieve closure objectives. Through this process, we work closely with Indigenous communities to integrate Traditional Knowledge and expertise. When developing reclamation plans, Okane focuses on highest value returning land use plans that are flexible and adaptable to climate change. When developing remediation plans, Okane works to manage concerns at the source, creating site-specific water management plans and solute balances to manage transport pathways.
Regardless of the returning land use plan, Okane takes a systematic approach to risk identification to identify and prioritize mitigation opportunities throughout the mine life cycle. This way, rehabilitation, reclamation, and remediation approaches can be effectively combined to achieve closure objectives and highest value returning land use.
Alberta Environment. (2002). Glossary of Reclamation and Remediation Terms Used in Alberta (7th ed.). Retrieved from https://open.alberta.ca/dataset/c9fa40a2-b672-441f-9350-39419b1df905/resource/856641d8-e0be-4f0a-996d-8683c25d5928/download/glossaryrecremediationterms7edition-2002.pdf
Yeldell, A., & Squires, V.R. (2016). Restoration, Reclamation, Remediation and Rehabilitation of mining sites: Which path do we take through the regulatory maze? In V.R. Squires (Ed.), Ecological Restoration: Global Challenges, Social Aspects and Environmental Benefits (Ch. 3). Nova Science.