Closure objectives for water treatment

Kaisa Turunen & Päivi M. Kauppila, Geological Survey of Finland, P.O. BOX 1237, FI-70211 FINLAND; email: kaisa.turunen(at), paivi.kauppila(at)
Due to the diversity of ore deposits, every mine site and its waters are unique in nature. Therefore also the water treatment objectives are site-specific for each mine site depending on the quality and quantity of the mine site waters. In addition, also local environmental, climatic and socio-economic conditions and requirements affect the decisions on the post-closure treatment of mine site waters.
The general objectives of post-closure water treatment typically include:
  • Restoration of the water quality to the level that does not present any long-term risks to the environment or human health
  • Long-term functioning
  • Long-term stability of the treatment products/residues
  • Integration with other water management measures (including management of tailings areas)
  • Sufficient capacity for peak floods, adaptation to seasonal fluctuations
  • Accordance with the regulative requirements (legislation, environmental and other permits)

One treatment objective can also be to enhance the use of the treated water by another party – on the other hand to decrease the need for the other party to abstract water from a natural water body and on the other hand to cover part of the treatment costs.

During last decades, a selection of water treatment technlologies have been developed, both passive and active methods, to fulfil the closure objectives. Closedure Chapter “Closure technologies” presents and evaluates in detail different water treatment techniques available for mine site water treatment, and “Case Studies” presents existing cases of the performance and applicability of these technologies.

General objectives of mine closure are described in Chapter “Mine Closure Objectives“.