Presented paper

IMWA2019 Students work

An Investigation Into European Water Quality Guidelines Applied To Mining

Cox, Melanie Anne; Bowell, Robert; Williams, Carl; Wickham, Craig; Declercq, Julien; Griffiths, Ruth; Charles, Jessica
SRK Consulting (UK) Ltd, United Kingdom

This abstract investigates the application of European water quality legislation and the implications this can have for mining projects. The Water Framework Directive (WFD) (2000/60/EC) and Groundwater Directive (GWD) (2006/118/EC) comprise the over-arching legislative documents used throughout Europe for the protection of water bodies. The WFD sets out a number of key objectives that Member States are required to achieve to ultimately monitor, protect and improve aquatic environments. Environmental Quality Standards (EQS) exist at a European level for the protection of surface waters. These specify priority substances and certain other pollutants which must be adopted by Member States (2008/105/EC and 2013/39/EU). In the case of groundwaters, the GWD defines specific criteria which must be adopted by Member States and certain key parameters which must be addressed, but countries are otherwise free to decide how to transpose the legislation in order to account for natural variability in water quality.

Within the context of mine water, the same legislation is generally the foundation for water quality evaluations. However, unlike solid mine waste that is legislated through the Mine Waste Directive (2006/21/EC) and Council Regulation 1357/2014 pertaining to hazardous properties, there is significant variation in the transposition and application of the water guidelines by Member States. The approach employed by Member States when establishing groundwater and surface water thresholds also seems to vary between a focus on the protection of aquatic ecosystems and a focus on water uses such as drinking water standards. This can lead to overly strict (and unworkable) requirements for mining operations and has implications with regards to the emplacement of mine waste and management of mine water.

Although the Mine Waste Directive requires Member States to comply with the Water Framework Directive and specifies the need for leachate evaluation from waste facilities, caution must be applied when evaluating hazardous properties of mine waste in terms of leachate generation that may impact water quality because evaluation of ecotoxicity properties typically focuses predominantly upon solid concentrations in the waste.

This study also evaluates limiting factors in the application of water quality guidelines in terms of what analytical limits of detection that can be realistically achieved by laboratories and also assesses an alternative approach of developing site-specific thresholds based upon natural background water quality data.