Physicochemical composition of wastes and co-located environmental designations at legacy mine sites in south west England and Wales: Implications for their resource potential

摘要

This work examines the potential for resource recovery from metalliferous mine wastes in south west England and Wales. It does this through an assessment of the physicochemical composition of several key metalliferous legacy mine waste piles and an analysis of their co-location with key cultural, geological and ecological designations. Solid samples were taken from 14 different sites and analysed for metal content, mineralogy, paste pH, particle size distribution, total organic carbon and total inorganic carbon. The majority of sites contain relatively high concentrations (in some cases up to several % by mass) of metals and metalloids, including Cu, Zn, As, Pb, Ag and Sn, many of which exceed guideline concentrations. However, the economic value of metals in the waste could be used to offset rehabilitation costs. Spatial analysis of all metalliferous mine sites in south west England and Wales found that around 70% are co-located with at least one cultural, geological and ecological designation. All 14 sites investigated are co-located with designations related to their mining activities, either due to their historical significance (e.g. mining infrastructure), rare species assemblages (e.g. lichens and bryophytes) or geological characteristics (e.g. mineralisation). This demonstrates the need to consider the cultural and environmental impacts of rehabilitation and resources recovery on such sites. Further work is required to identify non-invasive remediation and resource recovery methodologies to allow sites to be rehabilitated at minimal cost and disturbance.