MINING / 10 Oct 2019
Moving towards better mine closure planning in the Nordic Region
Modern mine closure planning is much more than drawing a cover system cross-section. Closure planning is an integrated part of the mine planning process and requires a holistic approach.
New guidance on closure planning
Within a year, two important new documents have been published:
- The new BREF-document “Best Available Techniques Reference Document for the Management of Waste in Extractive Industries” also known as MWEI BREF, was published in the end of 2018 by European Commission.
- ICMM (International Council on Mining & Metals) has published this year an updated mine closure guide, “Integrated Mine Closure, Good Practice Guide, 2nd Edition”.
These two documents have different roles. The objective of MWEI BREF is to instruct European Union Member States to ensure that operators minimize adverse impacts of extractive waste. MWEI BREF is supposed to link best available techniques into permitting procedures. The ICMM mine closure guide is primarily written for mining project developers and mine management. It focuses on proactive identification and management of risks and it links closure planning into the real life mining project development and mine management. Closure is understood as a part of the mine operations’ business.
Reading the BREF-document, correctly
One of the strengths of the new MWEI BREF document is that it forces the reader to link closure issues to all different mine life-cycle phases: planning phase, construction-operation phase and closure-post closure phase. We should, however, keep in mind that any user of the MWEI BREF document should be well versed in extractive waste management and mine closure. An unexperienced reader might suddenly think that he or she can just categorize the extractive waste and pick a basal structure and cover structure from the BAT-list. If it was this simple, mining would be a very low-risk industry.
The MWEI BREF document defines only a few generic BAT conclusions that instruct the planning process and are therefore generally applicable. Most of the “BATs” are risk-based. Using risk-based “BATs” requires knowing the site specific risks well. To understand site specific risks, assessments must quite often be taken beyond the formal regulatory requirements. The BREF-document does not include any complete list of potential problems and potential solutions (and it does not claim to do so either). This could be concluded that the most important “BAT” is actually BAT number 5, Environmental Risk and Impact Evaluation.
Applying ICMM good practice guide in the Nordic Region
Also, the ICMM mine closure guide focuses on risk management. The foundation for mine closure planning process includes systematic risk management and systematic knowledge base management. The right information must be available at the right time to support the decision making processes.
The ICMM guide also discusses the linkage between mine closure and economic planning. This is not a simple task either. There are many tools in economic planning and all of them do not work well in the mine closure context. For example, progressive closure can be challenging to assess economically: for example, net present value analysis may motivate companies to push closure work to the future, but this can be misleading, as scope of activity will not remain the same if the work is delayed. Progressive closure also reduces risks of cost overruns and may improve credit availability. Closure planning requires closure knowledge even from economy professionals.
In Nordic mine closure planning, the social perspective is often understated. Partially this is related to the rather highly organized governmental guidance and social structure in the Nordic countries. Still, even in the Nordic Region, there is a lot to improve in the management of social risks. For example, mine closure related social transition planning is seldom properly included in closure planning – despite the fact that social transition is one of the biggest impacts of mine closure.
Planning the closure – in a nutshell
Closure planning must be well integrated to mine technical-economic planning and impact assessment procedures. Any decision during the mine planning must be considered also in the post closure context. Such as what are the post closure contamination transport pathways from the waste rock storage facility? Where does the groundwater flow from the pit lake? What are the receptor impacts?
Mine closure must also be part of the very first project risk assessments. Conceptualization is a very effective tool in understanding risks. Based on the first risk identification, a pathway for investigation and planning can be generated. This pathway must be linked to the pathways in mine planning, permitting and consultation. An overall closure planning pathway is presented in Figure 1.
Figure 1. Closure planning procedure, our recommendation.
At the early stages of mine planning, the closure plan is just a rough draft, but closure planning is an iterative process. It includes loops to be repeated, while information increases and uncertainty decreases. Especially the definition of closure measures and impact assessments from a loop that may have to be repeated many times before a solution (with low enough receptor impacts) will be found.
Numerical assessment of impacts requires well-founded assessments and models: for example stability, net percolation, gas flux, seepage quality development, groundwater flow, pit lake stratification and surface water receptor behavior must be studied. Mine closure impact assessment is a complicated multidisciplinary job. Impacts may be challenging to predict well, but currently there is lack of even trying. A comprehensive modern toolkit is seldom used in the Nordic region, but it does exist.
We are getting better and better instructions and guidebooks, but these do not reduce the relevance of expertise. As ICMM closure guide states, mine closure is a part of the core business in mining. Who would plan lightly a core plan of the business? Mine closure may cost tens of millions of euros for the company. It is a big investment to make based on poor planning. If the selected measures perform poorly, the company will re-plan and re-implement, no matter what the initial environmental permit terms for the closure were.
For more information, please contact
Senior Consultant, PhD
Services for Mining and Exploration
+358 10 33 49737