Methods for assessing acid and metalliferous drainage mitigation and carbon sequestration in mine waste: a case study from Kevitsa mine, Finland

Authors: Savage, RJ; Pearce, S; Mueller, S; Barnes, A; Renforth, P; Sapsford, D Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_rep/1915_86_Savage

Cite As:
Savage, RJ, Pearce, S, Mueller, S, Barnes, A, Renforth, P & Sapsford, D 2019, 'Methods for assessing acid and metalliferous drainage mitigation and carbon sequestration in mine waste: a case study from Kevitsa mine, Finland', in AB Fourie & M Tibbett (eds), Mine Closure 2019: Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1073-1086, https://doi.org/10.36487/ACG_rep/1915_86_Savage



Abstract:
Previous studies suggest that the weathering of magnesium silicate minerals such as olivine, through the carbonation process, has the potential to sequestrate large amounts of CO2. In addition, as a result of alkalinity production, the beneficial impact of the process with respect to acid mine drainage (AMD) mitigation has been identified, although has been less well studied. The carbonation process is a potentially important aspect to assess as part of mine site waste characterisation and management. However, to date a standardised, practical and cost-effective methodology to assess the potential of carbonation to occur within mine waste facilities has yet to be developed and utilised widely. Within this study we present a case study from the Finnish nickel mine, Boliden Kevitsa, for which we have assessed the potential for carbon sequestration and AMD mitigation within ultramafic waste rock and tailings storage facilities over life-of-mine (LOM) and closure timescales. As part of the work carried out a set of laboratory tests and analytical tools have been developed that are practical, cost-effective and short duration and have potential to form the basis for standardised testing methodology. It has been demonstrated as a result of the work carried out that the waste rock storage facilities may offer an important role with respect to carbonation processes, as well as the tailings storage facility. This finding is significant given that to date, tailings facilities have generally been considered as having the most potential for carbonation processes, and as such have been the focus of most research. This finding was made possible because of the consideration of physical and thermodynamic aspects such as gas flux and waste fragmentation as part of the assessment methodology as well as the pure geochemical rate-based process of carbonation, which typically is the focus of similar studies.

Keywords: mineral carbonation, magnesium carbonates, carbonation potential, carbonation rate, AMD

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