The environmental impact of the Mount Polley mine tailings spill and related clean-up operations, British Columbia, Canada

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Since 1970, over 70 major reported failures of tailings dam impoundments have occurred around the world, and many of these have resulted in long-term damage to ecosystems and significant impact on communities that live beside and rely on impacted rivers for food and livelihood, and the loss of over 1000 lives. The environmental risks from such tailings dam failures are increasing because of the growing number of mining operations world-wide and because of the growing vulnerability of these types of environments to extreme events because of climate change. The proposed research aims to determine the environmental and geomorphological impacts of the August 4th 2014 Mount Polley tailings impoundment failure at the Mount Polley gold and copper Mine in British Columbia, Canada. The Mount Polley spill is one of the largest ever recorded (10 million m3 of water and 4.5 million m3 of arsenic-, copper-, nickel- and lead-bearing tailings), on the same scale as recent large spills in Aznalcollar, Spain (1998, 1.3 million m3 of tailings) and Ajkai, Hungary (2010, 6-7 million m3 of tailings). Among dam failures, the Mount Polley disaster is unique in that that the tailings contain an unusual mixture of contaminants (arsenic, copper, gold, manganese, nickel, lead, vanadium) enabling the impacts of a wide range of contaminants to be studied in a single event. In addition, the site is located within a mountainous forested catchment that is affected by severe winters, providing an opportunity to study remobilization of the very large quantities of spilled tailings due to the spring melting of snow. No data currently exist on the short- to long-term (months to years) behaviour of such tailings in soils and sediments and the effects of clean-up operations on their behaviour in this type of river environment. There is an urgent need for funding as establishing this geochemical behaviour requires immediate characterization of the spilled mine tailings and of the soils and sediments impacted by the spill. The proposed research will fill this knowledge gap by modelling the geochemical stability and reactivity of the wastes and by establishing the impacts of the spill and related clean-up operations on longer-term recovery of terrestrial and aquatic environments. This will be achieved by producing a physical, geochemical, mineralogical database for spilled tailings and sediments and soils affected by the spill. This dataset will provide an essential baseline for quantifying the stability and reactivity of gold-copper tailings, and allow the long-term environmental impacts of the Mount Polley spill and subsequent clean-up operations to be predicted. Airborne and ground-based geomorphological surveys will also be carried out prior to (in autumn 2014), and after the spring 2015 snow melt, to develop a sediment budget and an estimated contaminant flux to downstream affected areas. The results will be the first from a unique spill with an unusual mixture of contaminants located within a mountainous, forested catchment, affected by severe winters with prominent spring snow melt floods.