In the life of all mines there comes a time when the mineral is completely extracted and it is time to close the operation and start the restoration process to put it to use.
Although it is not easy to specify when the closure of the mine should occur (since this decision is influenced by several factors such as the market price of the metal or the cost of mining), all mines benefit from having a closure plan that is fully integrated and updated in the general business plan, that assumes a realistic cost and that establishes the time to run it.
Planning for mine closure is a complex process because it encompasses the decommissioning project, land rehabilitation, post-closure monitoring, and the necessary provisions for future land management after the mining cycle is complete.
We chatted with Evelyn Bingham, geologist and Senior Consultant Mine Closure SBC , who is one of the professionals with greater experience and process expertise in mine closure, to better understand the scope and challenges posed to the mining cycle, in a context such as the current one, in which sustainability standards imply great challenges for the companies that carry them out.
In terms of timelines, when should the closure process begin (including planning) and when is it over?
The best time to begin closure planning is prior to mining. Looking at mine closure as the mining, tailings impoundment and stockpile methods are being evaluated can contribute to developing an overall profitable mine.
Closure costs can be lowered if an operation is designed, constructed, and operated with closure in mind from the beginning. Closure planning from the beginning can result in slopes on stockpiles placed in a way that facilitate recontouring at mine closure. Surface water and groundwater protections can be built into tailings impoundment and stockpile design that will avoid changes in drainage and expensive water treatment in the long run.
Depending on the mine configuration, some progressive closure practices may be implemented during mine operations, spreading the cost of closure out over years. Recontouring and revegetating a waste stockpile that has reached its maximum design capacity during mine operations can be planned and implemented as a progressive closure practice.
What is the importance of the process of closing a mine from the business point of view, that is, of the operators of a mine, and that of the authorities?
For mine owners, the importance has to do with costs, which can be between ten and hundreds of millions of dollars. Mining companies have found robust closure planning to be an essential tool in managing costs and creating an overall profitable mine operation.
As for the authorities and international financing organizations, the closure plan has been gaining importance to the extent that it has been found that in the past some mining practices have produced problems for the communities and high costs of environmental clean-up for the taxpayer. For this reason, nowadays new mines must have an approved closure plan before starting mining activity, also as a requirement for their authorization. Additionally, most governments require existing mines to develop closure plans to retain or renew operating permits. These regulatory requirements generally provide the basis for developing assurance plans or other financial guarantee requirements to prove that mine closure costs are adequately provisioned.
Regarding the costs of the closing process: what percentage of the total cost of a project represents approximately the part destined to the closing? And what is the main cost within the budget for the closing?
All mining projects are so unique, in my experience, there really is no rule-of-thumb that applies to estimating mine closure cost in relation to project or operating costs. Consider that the closure cost for a high-grade, underground mine that backfills most of its waste, and has no surface subsidence will be very different than a low-grade, open-pit mine that demands creation of large surface tailings impoundments and waste stockpiles. Additionally, the location, geography, geology, climate, and environmental aspects of each mine effects each closure plan.
As the mining industry refines and standardizes the closure planning practice and we have more mines that are successfully closed, perhaps industry organizations will develop rules-of-thumb for different classes of mines in similar environments. For now, each mine closure team, typically including mine engineering and environmental specialists, needs to work out and document the closure plan and associated cost for each particular mine.
What are the indicators that a closing process has been successful?
Water quality protection and a clear, achievable post-closure land use are two good indicators of both a successful mine closure plan and an executed mine closure project. In many cases, if closure objectives include fully protected surface water and ground water quality into perpetuity, the mine closure is successful. It seems in the process of long-term water protection; most other closure risks are mitigated.
Likewise, if the closure objectives include a post-closure land use that is accepted by external stakeholders such as government and local community, the mine closure can be thought of as successful. Post-closure end land use can range from keeping selected buildings and infrastructure for use by the community, use of infrastructure for solar, wind or hydro electricity production, and returning land to sustainable wildlife habitat depending on the specific mine locality, area and business needs.
What are the main mistakes that can be made when planning a closing process?
Mining companies miss an opportunity when they consider closure planning to be simply a checkbox to meet a government requirement. Developing a closure plan that is fully integrated with the life of mine business plan has many benefits for team building and business aspects.
Mining companies miss an opportunity when they look at closure planning as merely a box to tick to satisfy a government requirement. Developing a closure plan that is fully integrated with the life-of-mine business plan has many benefits for team building and the business aspects.
Closure plan development includes in-house specialists such as senior management, mine engineering, environment, external affairs, legal and financial staff. This internal team, frequently led by consulting specialists to assist in “workshopping” the risks and opportunities presented by integrated closure planning, can come out of the closure planning process with stronger working relationships and a better understanding of the business.
Are there international application protocols that can be useful for these processes? Which? If there are, what are the differences between these protocols and how should they be selected depending on the type of operation we have?
The International Council on Mining & Metals (ICMM), a mining industry led organization, has a very useful set of documents on mine closure planning under the “Environment” tab on their website (icmm.com). The documents include Integrated Mine Closure, Financial Concepts for Mine Closure, and Key Performance Indicators: Tool for closure that have been designed to meet international governance and best practice. This is a good start to understanding how to develop a closure plan from the beginning or update an existing closure plan.
Again, consultants specializing in mine closure and familiar with the ICMM closure documents are sometimes a good option to help an internal mine closure team review existing closure plans, structure internal closure risk assessments, and develop comprehensive closure plans in accordance with international best practices and local regulation.
Do you remember any particularly successful case, in which the different parties were very satisfied with the closing process carried out?
ICMM is a good resource to find examples of mine closure projects. Case studies of best practice in mining, including closure projects, can be found under the “News and Resources / Case Studies” tab on the ICMM web site (icmm.com). Another interesting web look at mine closure projects is the “Mine Closure” group on Linked In (linkedin.com) with almost 2,000 members. In researching successful mine closure projects, you will find that most mine closures are “in progress” and there only a handful that could be considered complete where the mining company has relinquished the property over to a 3rd party with full approvals of government, community and other stakeholders. The “post-closure” period where monitoring, refining end land use, and assuring that all environmental and business risks have been mitigated is typically a long one. This makes a well-designed closure plan with regular updates even more important.
Lastly, are there any other mine closure issues you want to discuss? Tell us about any aspect that you find interesting, please.
In my experience as a closure planning specialist, I have found solid closure risk assessment to be the foundation of an effective closure plan in my experience as a closure planning specialist, first with BHP and later as a consultant working on other closure planning projects internationally. Identifying the closure risk that is unique to every mine property and expressing that risk in a way that senior management teams can understand and use to make decisions results well defined closure costs that support government permits and the overall mine operation. I recommend mining companies use their own standard to business risk standards and guidelines to assess closure risk.
The support of a specialist closure consultant has worked well for many miners by helping the internal team to identify risks and develop mitigation measures to achieve an acceptable level of risk (these mitigation measures then become the closure plan). A well thought-out closure plan integrated with the life of mine plan becomes an enterprise risk management tool, as well as an element in meeting administrative requirements and the expectations of other stakeholders.
Evelyn Bingham is Senior Consultant at SBC. If you want to arrange a meeting with her you can write to firstname.lastname@example.org.