De-risking tailings from copper mining: mineralogical and geochemical controls on environmental impacts and resource potential under different climate conditions

Project Highlights

• Investigate the controls (mineralogical and geochemical) on the environmental impact of copper mine tailings and assess their resource potential, with a focus on reducing the environmental hazards of legacy tailings and incentivising their remediation.
• Explore the effects of a changing climate on copper tailings and how this will change tailings related hazards and resource potential.
• Gain a holistic overview of copper mine waste, remediation and tailings, and a broad range of employability-enhancing skills such as remote sensing, field sampling, mineralogical and geochemical characterisation, and risk assessment. 

Overview

The energy transition will need a large amount of metal, particularly copper which is essential for all types of renewable power generation and for electric vehicles. However, copper deposits are typically low grade, with an average operating grade of 0.53% meaning >90% of the mined rock goes to waste. Copper demand is predicted to rise by 50% by 2040, meaning that the amount of waste from copper mining will also increase dramatically. Tailings are a voluminous by-product of processing ore and are a mixture of finely ground waste rock and processing effluent. They often contain highly reactive minerals and potentially harmfully elements and chemical species, and must therefore be safely and securely isolated from the environment, which is often not achieved. Around half the current total global volume of tailings is from the processing of copper ores, and many of these tailings storage facilities are situated in areas which are susceptible to climate change-related hazards such as flash floods and extreme weather events.

The project will focus on the resource potential and environmental impacts of copper tailings, including tailings dust and acid mine drainage (AMD), and how these are likely to evolve in a changing climate. Tailings, in particular legacy tailings, are not only a potential environmental hazard, but also a potential resource of low-grade copper and other important minor metals (e.g. Co, Ga, Te). Understanding their resource potential through geochemistry and geometallurgy would guide resource recovery from waste, which in turn could reduce the environmental hazards of legacy tailings and help offset costs of remediation.

The project will compare the geochemistry and mineralogy of copper tailings and associated dust and AMD from a variety of climatic regions in order to assess: 1) the resource potential of copper in both tailings and AMD; 2) the mineralogical controls on environmental impacts of copper tailings, tailings dust and AMD; and 3) the effect of present and future climate on the mineralogy and geochemistry of tailings. The mineralogical and geochemical characterisation of tailings will be used in conjunction with data from remote sensing to develop tailings monitoring and characterisation techniques, including resource assessment.

Key research questions

This project aims to answer the following key research questions:

1. What is the resource potential of copper (and other metals) in both tailings and acid mine drainage?
2. What are the mineralogical controls on the environmental impacts of copper tailings, tailings dust and acid mine drainage?
3. What is the effect of present and future climate change on the mineralogy and geochemistry of tailings? 

Methodology

The project focus will be chosen by the student according to their interests during the initial project planning and literature review stage, however the core methodologies are:

• Field sampling to collect samples of tailings, tailings dust and acid mine drainage in case study locations in different climatic regions. Suggested case studies are Chile (Arid climate), Cyprus (Mediterranean climate), and the Philippines (Tropical climate, pre-existing dataset and samples from PROMT NERC project for comparison).
• Mineralogical and geochemical characterisation of samples using µXRF scanner, SEM-EDS, XRD and whole rock geochemistry methods (ICP-MS/XRF) to determine both resource and contamination potential of tailings, dust, and acid mine drainage.
• Remote sensing of case study areas – can include investigating erosion rates using time series satelite imagery, use of hyperspectral mineralogy, and environmental monitoring.
• Risk assessment and data synthesis focussing on how mineralogy affects tailings risk, and how this may change over time due to climate change.

Possible timeline

Year 1: Induction and initial training at UCL. Literature review and methodology development, including preliminary remote sensing work and sampling site selection. Field sampling in Autumn (Cyprus/Chile). Sample preparation and initial characterisation.

Year 2: Mineralogical and geochemical characterisation of samples throughout the year at UCL/NHM/University of Leicester. Further field sampling in Spring if needed. Continue remote sensing work. Start preparing paper manuscripts, and submit an abstract to a conference such as MDSG or SEG.

Year 3: Finish geochemical analysis and analyse data. Data synthesis to generate resource assessments and hazard risk assessments. Prepare thesis for submission, and submit paper manuscripts. Present final findings at an international conference such as International Conference on Tailings Management, or SGA 2027.

Training and skills

TARGET researchers will participate in a minimum of 40 days training over the 3.5 years of study composed of:

• an annual one-week workshop dedicated to their year group, and tailored to that cohort’s needs in terms of skills development – for the first three years of their study;
• an annual all-TARGET workshop with cross-year interactions, advanced training and opportunities to specialise in particular areas – all years of study;
• a number of one-day workshops;
• additional online events and in-person workshops attached to relevant conferences.

In addition to the TARGET mandatory training the student will receive project-specific training, such as in laboratory techniques, sampling and field work, risk assessment, and remote sensing. They will join a 60+ cohort of PhD students in a vibrant department and will have access to UCL’s doctoral training, including academic writing, entrepreneurship, and presentation skills. They will also be trained to teach and will gain experience as a demonstrator in our department. The student will join the UCL Earth Resources Centre and be encouraged to attend and contribute to group meetings, seminars and networking events. 

Partners and collaboration

The student will spend most of their time between UCL and NHM. They will also spend ~3 months total undertaking laboratory work at the Centre for Sustainable Resource Extraction at the University of Leicester. There will be regular (~monthly) virtual supervisory team meetings with the student, and at least one in-person meeting per year.

There may also be the opportunity to collaborate with CGG, who would provide training, supervision, and work placements. Additionally, there may be the opportunity to collaborate with the Chilean National Geological and Mining Service (SERNAGEOMIN), and with the Geological Survey Department of Cyprus. 

Requirements

Applicants should ideally have a Masters level degree in Geology/Geoscience/Earth Science, or equivalent industry experience, with an interest in mineralogy, geochemistry and the environmental impact of mining.

Further details

For more information please contact Dr Katie McFall.