Tommi Kauppila, Geological Survey of Finland, PO Box 1237, 70211 Kuopio, Finland; tommi.kauppila(at)gtk.fi
All mine closure plans are living documents that should be reviewed during the life span of the mine to make sure that at all times they provide a sound, demonstrable basis for an environmentally (ecologically + human health), economically and socially sustainable mine closure.
There are three main ways to achieve this:
- Periodic review
- Review based on changes in preconditions for closure
- Review when data accumulation and planning stage facilitate more detailed plans
Periodic reviews may be required by local legislation (as in Finland and in Western Australia) or such requirements may be included in the conditions of the licenses and permits for the mining operation. Typically, the frequency of such periodic reviews should take into account the expected life span of the mine as well as the planned stages of the operations (e.g. the sequence of pits to be opened and mined). Typically, shorter lifes of mine call for more frequent reviews and mine closure plans are conveniently updated when mining enters a new operational phase. It should be noted that the review may not be a big task if no major changes have happened. In most cases, however, more environmental and operational monitoring data has been collected since the last version and should be included in the plan.
Review at regular intervals is the most common way to keep the CMP up to date, mainly because of the financial implications of the document and its connection to the annual mine planning, business planning, and budgeting cycles.
Review based on changes in conditions is commonly done when substantial chances to the operations are planned. Expansions and extended lifes of mine are typical examples. In some jurisdictions, changes that require new or updated mining proposals or environmental permits also involve submission of updated mine closure plans. If this is not the case, it is nevertheless advisable to check the CMP in conjunction of any new permitting exercise because the changes likely require some adjustments also to mine closure plans. Similarly, revisions are appropriate when the project changes from one phase to the next (e.g., feasibility-construction-operation), especially as these changes often involve changes in management or ownership as well.
Besides planned changes in the project, unforeseen factors may warrant changes in the CMP. Examples of such factors include newly identified or incorrectly estimated environmental or social risks; structural failures, flawed designs, sizing or construction; other non-compliances; unpredicted changes in climatic conditions, hydrology, surrounding land uses etc. (ICMM 2008)
Mine closure plans should be reviewed when either the planning process or accumulation of process and environmental monitoring data facilitate more detailed and realistic closure plans than early in the project. Certain engineering designs and specifications that were at a concept stage at the start of the project may become more definite later in the project and the final designs also often differ from the original ones. Such changes make it possible to review at least these parts of the CMP. In addition, more realistic closure plans and targets become possible when the accumulation of environmental, social and economic monitoring data provides new insights into the effects of the mining operation on its surrounding environment.
Accumulation of monitoring data and other information can also be structured in the CMP. It can be based on a formal analysis of knowledge gaps early in the life of the CMP and a plan to systematically fill these gaps with targeted data collection and testing.
Figure 1. An example of updating the Closure Management Plan with changes in the mining project (blue down arrows). The arrows also indicate phases when major changes to the CMP are required if the CMP is revised with regular time intervals.
ICMM 2008. Planning for Integrated Mine Closure: Toolkit. International Council on Mining and Metals, London, UK. 84 p.