Developing enhanced weathering methods in mine tailings for CO2 sequestration

Enhanced weathering and carbonation strategies for mine wastes, where the natural process of rock weathering and carbonate precipitation is sped up to uptake CO2, is a potentially significant sequestration method. However, on-site pilot schemes are required to fully realise the high CO2 storage potential. The EU-funded DETAILS project will address this challenge by implementing new technologies in mine wastes to reduce CO2 emissions by initiating enhanced weathering and carbonation in mine wastes through novel bioreactor technologies. This will surpass current state-of-the-art technologies by focusing on delivering on-site testing on a range of voluminous and suitable materials with industry partners. The new bioreactor system will work to modify pH and harness heat and CO2 point sources at mine sites.

Objective

The Paris Agreement goal to limit global average temperature increase to 1.5°C cannot be achieved without atmospheric CO2 removal on the order of tens of gigatonnes per year by 2100; a formidable challenge requiring urgent assessment. Further delayed mitigation will have an increasingly damaging effect on the environment. The challenge is pertinent to the mining industry, which produces 1-5 Gt CO2 per year and is susceptible to financial impacts due to nascent carbon taxes worldwide.

Enhanced weathering and carbonation strategies in mine wastes, where the natural process of rock weathering and carbonate precipitation is sped up to uptake CO2, is a potentially significant sequestration method, requiring on-site pilot schemes to fully realise the high CO2 storage potential. This project aims to implement new technologies in mine wastes to reduce CO2 emissions. This will be achieved by developing an innovative method to initiate enhanced weathering and carbonation in mine wastes through novel bioreactor technologies.

Despite the beneficial conditions at sites, mining companies are not currently equipped for sequestration schemes, meaning new approaches are required to leverage wastes for CO2 uptake. Currently, the state-of-the-art falls short of rigorous industrial-scale testing, neglecting factors such as the geochemical variability of host rocks across sites and the practicality of initiating schemes on a site-scale. This proposal will go beyond the state-of-the-art by focusing on delivering on-site testing on a range of voluminous and suitable materials with industry partners. This new bioreactor system will work to modify pH and harness heat and CO2 point sources at mine sites to facilitate this mine site process stream shift.

This fellowship will be carried out at Geosciences Barcelona (CSIC). The applicant will carry out a secondment at Global Ecology Group and work with both academic (Universities of Southampton and Oxford) and industry partners (Rio Tinto).