A Geometallurgical Approach to Assessing Critical Metal Mobility and Recoverability from Ultramafic Mine Tailings

• Author / Creator

  Honda-McNeil, Makoto J

• Critical metals (e.g., nickel and cobalt) are increasingly in demand for the production and storage of cleaner energy but their supplies are finite. Ultramafic mine tailings could be reprocessed as a source of critical metals. These waste materials host an array of critical transition metals and can sequester atmospheric carbon during weathering. However, the partitioning behavior of nickel and cobalt between mineral phases and the abundances of these metals in ultramafic tailings and greenfield ore deposits is imprecisely known. Ultramafic tailings and ore from post-mining (Lord Brassey, Tasmania) and pre-mining (Record Ridge, British Columbia) settings were analyzed in order to observe the behavior of critical transition metals over the mining lifecycle. X-ray diffraction (XRD) supplemented by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) were used to identify widespread sulfides, oxides and alloys, which host numerous critical transition metals. Raman spectroscopy was used to identify amorphous carbonate and iron oxyhydroxide minerals, which sequester these metals upon alteration and weathering, and X-ray fluorescence microscopy (XFM) displayed an increase in the concentration of nickel and cobalt in weathered and sulfide-rich zones. The integration of quantitative X-ray diffraction (QXRD) and electron probe micro-analysis (EPMA) data from the Lord Brassey samples was used to (1) determine that these tailings qualify as low-grade nickel and cobalt ore and (2) produce an analytical tool for accurate calculation of whole rock elemental abundances that provides supplementary mineralogical abundances and compositions. This methodology produced results comparable to an industry whole rock analysis and provides a better understanding of mineralogy, stoichiometry and the grade of tailings with general applicability to geometallurgical assessments of tailings and ore. The results of this thesis indicate there is merit in reprocessing ultramafic mine tailings for nickel and cobalt and we suggest that tailings storage facilities could be incorporated into the ore processing circuit as part of mine plans.

• Subjects / Keywords

  • Ultramafic Mine Tailings
  • Critical Metals
  • Nickel
  • Cobalt
  • Geometallurgy

• Graduation date

  Fall 2022

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-a67h-yq60

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.