Resource or environmental liability? Development of novel ground imaging tools to identify critical metals and environmental susceptibility in legacy mine wastes

Overview

The overarching objectives of the project are to develop novel ground imaging approaches to determine the spatial distributions and concentrations of critical metals in mine waste (i.e. resource potential), and to assess potential environmental impacts of reprocessing and remediating versus leaving sites undisturbed.

A legacy of the centuries of mining in the Cornubian Orefield has been the production of large volumes of mine waste. Our hypothesis is that some of these wastes will contain economic quantities of critical metals (e.g. tin and tungsten) when reprocessed using modern approaches.

However, the assessment of this potential resource is challenging. These materials (including waste rock, spoil, tailings and slags) are difficult to sample and characterise due to considerable heterogeneity at both the clast and site scale, there is variable supergene alteration, and their depth is largely unconstrained. Furthermore, these wastes have the potential to cause significant negative environmental impacts (acid mine drainage and toxic metal release), which could be exacerbated during reprocessing and/or remediation.

Our focus will be on developing geophysical tools (supported and validated by mineralogical and hydrogeological studies) to volumetrically image and characterise these wastes. We will deploy an integrated suite of methods, coupled with supervised machine learning, with a view to classifying the waste and developing resource distribution models for selected trial sites. These same geophysical tools will also be used to develop 3D ground models defining waste structure and underlying geology and 4D models of soil moisture dynamics and groundwater flow to improve our understanding of the environmental implications of disturbing historic waste.

We anticipate that the approaches developed within this project will significantly advance the state-of-the-art for mine waste characterisation, and will be applicable beyond the Cornubian context. Consequently, once an approach has been established and trialled, we will seek to develop pilot studies with international colleagues at other mine waste types, e.g. copper-gold tailings.

The project will be a collaboration between the British Geological Survey (expertise in hydrogeophysics & mineralogy and materials characterisation), University of Leicester (economic geology and mineralogy), Camborne School of Mines (economic geology & Cornubian Orefield), and Terradat (UK) Ltd (applied geophysics).