Testing Contamination Risk Assessment Methods for Mine Waste Sites

Major incidents involving mine waste facilities and poor environmental management practices have left the legacy of thousands of contaminated sites like in the historic mining areas in the Carpathian Basin. Associated environmental risks have triggered the development of new EU environmental legislation to prevent and minimize the effects of such incidents. The Mine Waste Directive requires the risk-based inventory of all mine waste sites in Europe by May 2012. In order to address the mining environmental problems, a standard risk-based pre-selection protocol has been developed by the EU Commission. The protocol consists of 18 simple questions about contamination source, pathway and receptor. This paper evaluates the protocol by applying it to real-life cases, adopting it to local conditions, comparing to the similar method of the European Environmental Agency standard Preliminary Risk Assessment Model (PRAMS) and by carrying out uncertainty analysis. All together, 145 ore mine waste sites have been selected for scientific testing and evaluation using the EU Mining Waste Directive (MWD) Pre-selection Protocol as a case study from Hungary. The proportion of uncertain responses to questions in the protocol for the mine waste site gives an insight of specific and overall uncertainty in the data used. Questions of the EU MWD Pre-selection Protocol are linked to a GIS system, and key parameters such as the topographic slope and distance to the nearest surface and groundwater bodies to settlements and protected areas are calculated and statistically evaluated in order to adjust the RA models to local conditions in Hungary. Results show that the adjustment of threshold values to local conditions is necessary; however, the EU MWD Pre-selection Protocol is robust and is relatively insensitive to threshold values. Results of the EU MWD Pre-selection Protocol are consistent with the pre-screening European Environmental Agency PRAMS model which further confirms that the Protocol delivers reliable selection results that are not sensitive to the selected parameters. An interesting outcome of the study is that the highest uncertainty is associated with the engineering conditions of the waste facilities, such as the heights and size.