Characterisation of mining waste
Teemu Karlsson1 & Henna Punkkinen2, 1Geological Survey of Finland, P.O. BOX 1237, FI-70211 Kuopio, FINLAND, e-mail: teemu.karlsson(at)gtk.fi, 2VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Finland, e-mail: henna.punkkinen(at)vtt.fi
The characterisation is needed for the prediction, prevention and management of the environmental impacts of the mining wastes. The prediction of the mining wastes potential to produce AMD and other harmful drainage is crucial when planning the waste facilities, and estimating the utilisation possibilities of the waste materials and selecting suitable methods for the closure and rehabilitation of the waste facilities.
The Decision 2009/360/EC of the European Commission states that: “The purpose of the characterisation of extractive waste is to obtain the relevant information on the waste to be managed in order to be able to assess and monitor its properties, behaviour and characteristics and thereby ensure that it is managed under environmentally safe conditions in the long term. Furthermore, the characterisation of extractive waste should facilitate the determination of the options for managing such waste and the related mitigation measures in order to protect human health and the environment.”
The prediction is challenging and the drainage water quality of the waste facility can be misjudged if the prediction is not properly performed. There is a variety of both standardized and non-standardized methods available for mine waste characterisation. The specification of properties and selection of methods depend on the geological data of the deposit (e.g. ore type, mineralogy), in accordance with which the primary assessment can be made of the potential acid formation and neutralising capacity of the mine waste produced by the processing of ore, and of the occurrence of potentially harmful chemical elements. Depending on the primary estimates, suitable mineralogical and chemical analysis methods can be chosen for each waste fraction. Figure 1 shows a chart for the procedures typically used for the characterisation of mine waste. (Kauppila et al. 2013, Technical Committee 2012)
Figure 1. Characterisation procedure for mining waste (Kauppila et al. 2013).
According to the Finnish Government Decree on waste from extractive industries 190/2013 Annex 3 (see Legislation regarding characterisation of mining waste), mine waste characterisation should include the following things:
- Background information of the mining operation
- Geological background of the exploited deposit
- Waste type and its intended handling
- Geotechnical behaviour of the waste
- Geochemical characteristics and behaviour of the waste
Since the amounts of the mining wastes are typically large, succesful characterisation requires proper sampling and pretreatment of the samples. In addition to the laboratory measurements, valuable information on the mining wastes and their effluent quality can also be collected through field investigations. Hydrological and geochemical modelling is also often applied to evaluate the drainage quality of the mining wastes.
Regarding the collection and evaluation of information, see:
For further information concerning the mine waste characterisation, see the Annex 4 of the Reference Document on Best Available Techniques for Management of Tailings and Waste-Rock in Mining Activities(European Commission 2009) and Characterization of waste – Overall guidance document for characterization of wastes from extractive industries (Technical Committee 2012).
EC 2009. COMMISSION DECISION of 30 April 2009 completing the technical requirements for waste characterisation laid down by Directive 2006/21/EC of the European Parliament and of the Council on the management of waste from extractive industries (2009/360/EC). http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32009D0360
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
Finnish Government Decree 190/2013. Government Decree on Mining Wastes 14.3.2013. http://www.finlex.fi/fi/laki/alkup/2013/20130190
Kauppila, P., Räisänen, M.L. & Myllyoja, S. (eds) 2013: Best Environmental Practices in Metal Ore Mining. Finnish Environment Institute 29en / 2011. 219 p. https://helda.helsinki.fi/handle/10138/40006
Technical Committee CEN/TC 292 2012. Characterization of waste – Overall guidance document for characterization of wastes from extractive industries. CEN/TR 16376:2012.