• Leaching of nickel, copper and cobalt from alloys
  • Patented smelterless process for treating Ni-Cu-Co sulphide concentrates containing PGM by pressure leach of base metals, cyanide leach of PGM and delivery of high grade concentrate to platinum refinery.
  • Upgrade of copper concentrates for smelting using pressure oxidative and non oxidative leaching
  • Nickel and cobalt MHP to metal
  • Nickel and cobalt oxide leach to MHP
  • Recovery of nickel from low grade nickel heap leachates
  • Capacity increase opportunities for existing autoclaves employing exothermic processes (flash thicken recycle)
  • Autoclave leach process for alloys (flash recycle)
  • Integration of POX and NONOX autoclave systems


  • Increasing the Capacity of Existing and New Autoclave Circuits – ALTA 2006 Copper Conference (GM Dunn)
  • Increasing the Capacity of Existing Exothermic Autoclave Circuits – Pressure Hydrometallurgy 2004 - Canadian Institute of Mining Metallurgy (GM Dunn & HW Scriba)
  • Operations and Improvements to the Lonrho Platinum Base Metal – EPD Congress TMS 1999 (N Steenekamp & GM Dunn)
  • Nickel Cobalt Separation with Superoxidants – Hydrometallurgy and Refining of Nickel and Cobalt 1997- Canadian Institue of Mining Metallurgy (GM Dunn & HE Holliday & H Schubert)
  • Iron rejection and impurity removal for nickel leach liquor at Impala platinum Ltd – Iron Control in Metallurgy Symposium 1986 (R Plasket & GM Dunn) – Editors JE Dutrizac & AJ Monhemius
  • Uranium Recovery by Continuous Ion Exchange of Alkaline Leachate - ALTA Conference May 2010 (GM Dunn, John Vagenas, Yong Yong Teo)