Closure objectives / Monitoring

Lauri Solismaa & Päivi Kauppila, Geological Survey of Finland, PO Box 1237, 70211 Kuopio, Finland; lauri.solismaa@gtk.fi

The primary reason for environmental monitoring of the mine site following closure is to ensure that remediation measures, including earthworks, water treatment, and drainage systems, function as intended and in accordance with closure criteria. In addition, site surveillance may be necessary to demonstrate that the mine site remains safe and poses no environmental or health risks. Regular monitoring also allows for a proactive response where the rehabilitation process is found to be deficient, or in the event of a structural failure. Mandatory monitoring requirements during active mining, as well as following cessation of operations and closure, are specified in environmental legislation. (Heikkinen et al. 2008)

The objectives of the monitoring are typically divided into monitoring of:

  • physical stability,
  • chemical stability,
  • biological stability, and
  • socio-economical stability.

The following paragraphs list these objectives in a more detail based on the publications by Brodie et al. (1992), MMSD 2002, Heikkinen et al. (2008) and EC (2009).

Closure objectives for monitoring of physical stability

  • All remaining anthropogenic structures are physically stable, sustainable to erosion and safe, and impose no risks to public health in the long-term
  • Closure is appropriate to the requirements and specifications of the location of the site in terms of climatic (e.g. rainfall, storm events, seasonal extremes) and geographic factors (e.g. proximity to human habitations, topography, accessibility of the mine)
  • Structures are performing the functions for which they were designed

Closure objectives for monitoring of chemical stability

  • All remaining anthropogenic structures (mine wastes and infrastructure) are chemically stable and impose no risk to public health or environment throughout all phases of their life-cycle
  • Closure is appropriate to the site-specific requirements in terms of the quality of surface water, groundwater and soils

Closure objectives for monitoring of biological stability

  • The biological environment is restored to a natural, balanced ecosystem typical of the area or is left in such state so as to encourage and enable the natural rehabilitation of a biologically diverse, stable environment

Closure objectives for monitoring of socio-economical stability

  • Negative socio-economical impacts are minimized
  • Closure aims at securing the amount and quality of the natural resources of the site and rehabilitation is such that the ultimate land use is optimised
  • Adequate and appropriate readily available funds are allocated for the closure
  • Closure enables the productive and economical post-operational land use following the principles of sustainable development
  • Requirements of the local communities are taken into consideration to appropriate extent

Figure 1. Example of tailings aftercare: a field made on top of the tailings area at the Mustavaara iron-vanadine mine in northern Finland. Photo © Lauri Solismaa, GTK

References

Brodie, M.J., Robertson, A.M. & Gadsby, J.W. 1992. Cost effective closure plan management for metal mines. http://www.robertsongeoconsultants.com/papers/metal_mines.pdf

European Commission 2009. Reference Document on Best Available Techniques for Management of Tailings and Waste-Rock in Mining Activities. January 2009. http://eippcb.jrc.ec.europa.eu/reference/mmr.html

Heikkinen, P.M. (ed.), Noras, P. (ed.), Salminen, R. (ed.), Mroueh, U.-M., Vahanne, P., Wahlström, M., Kaartinen, T., Juvankoski, M., Vestola, E., Mäkelä, E., Leino, T., Kosonen, M., Hatakka, T., Jarva, J., Kauppila, T., Leveinen, J., Lintinen, P., Suomela, P., Pöyry, H., Vallius, P., Nevalainen, J., Tolla, P. & Komppa, V. 2008. Mine closure handbook. Espoo: GTK; VTT; Outokumpu Oyj; Finnish Road Enterprise; Soil and Water Ltd. 169 p. http://en.gtk.fi/informationservices/publications/publications/latest/publication/EJ74.html

MMSD 2002a. Mining for the Future. Appendix B: Mine Closure Working Paper. Mining, Minerals and Sustainable Development, Report No. 34, International Institute for Environment and Development /  World Business Council for Sustainable Development. 22 pp.