Mine Closure - Steps in Closure Plan Development

The typical steps for closure planning are shown in Figure 1. These steps also provide a logical order in which to develop and present the various sections of a Closure Plan Report. They provide the reader with a progressive description of the material required to understand the need for, nature of, effectiveness of, and cost the Closure Plan.

Any closure plan must consider the long-term physical, chemical, biological and social/land-use effects on the surrounding natural systems (aquatic, groundwater, surface water etc.). Therefore there must be an understanding of the pre-mining environment (step 1) and the effects of past and future mine development (step 2) on the pre-mining environment. Operational control measures must be selected (step 3) for implementation during mining in order to minimize the impact on the surrounding ecosystems. Impact assessments (step 4) must be done prior to measures selection as well as periodically during operations in order to determine the success of the measures implemented. Alternative mine closure measures are developed (step 5) and assessed (step 6) during mine design to ensure that there are suitable closure measures available to remediate the impact of the selected mine development.

If suitable remediation or closure measures cannot be identified or achieved, then it may be appropriate to revise the type of mine development proposed (return to step 2). Once a technically acceptable mine development and closure plan has been developed it is necessary to prepare a monitoring and maintenance plan (step 7) that will monitor the system performance during operations and post closure and provide for the maintenance necessary to ensure the long term functionality of the system components. Throughout this process, costing and scheduling evaluations (step 8) are completed, if the costs are too onerous, or if fatal flaws in the design are identified, the process returns to the design phase (step 2) and alternative measures are evaluated

Once an acceptable plan is completed, an acceptable form of financial assurance is developed and provided (step 9) in order to cover the costs of plan implementation, long term operations, monitoring and maintenance of the site post closure. The final stages of the closure plan process involve the application for (step 10) and approval by (step 11) the regulatory agencies of the Closure Plan, and implementation (step 12) at the end of mine life.

Figure 1. Typical Steps in the Closure Plan Development Process.

The Closure Plan document itself, must be completed in a logical manner which will provide the reader with a description of the area from pre-mining through to closure. The Closure Plan should also provide a discussion of the impacts (positive and negative) of mining on the surrounding environment, socio-economics, land use, health and safety etc. during operations, at closure, and over the long term as the reclaimed site responds to on-going natural processes of soil and vegetation evolution, erosion, sedimentation, chemical and physical weathering, frost action, biotic activity and during extreme events of floods, fire and earthquakes. This long term response is esentially an assessment of the sustainability of the site post closure and defines the need for long term monitoring and maintenance required by the site, i.e. the 'burden' placed on succeeding generations. The detailed description of the closure plan measures and the anticipated mitigated impacts can then be provided. A typical Table of Contents for a mine closure plan is provided in pdf form here.