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Experience
The Principals (Andrea Gerson and Roger Smart) have a combined experience of more than 45 years in minerals processing and acid mine drainage R&D working directly with company staff for process and remediation improvement and enhanced efficiency.
Minerals Processing
Examples
  • AMIRA International P260 Mineral Flotation series of projects (1991-2005) on improved minerals processing in flotation separation with sponsorship from more than 25 mining companies (national and international). Contribution (1994?2005) to $318M in net delivered present value (1994-2006) from this project in improved recovery, improved grade and quality of concentrates and reduced operating costs assessed by RMDSTEM Ltd. resource management and consulting group.

  • Determined muscovite reporting mechanisms to the sulfide concentrate at Kanowna Belle Gold Mine of Delta Gold Limited. A $1.5M capital expenditure was justified on the basis of this work with a payback period of 1 year.

  • Increased copper concentrate grade at Mount Isa Mines Limited Copper Concentrator by 4.5% by removal of carbonaceous pyrite in preflotation. Conditions to minimise loss of chalcopyrite to preflotation concentrate identified.

  • Increased copper recovery by 4% at Red Dome Gold Mine (Queensland) following stabilisation of water supply quality using different combination of process water streams.

  • Identified interference with flotation grade. Addition of polyacrylamide to lead circuit of the Cannington Concentrator of BHP Minerals to depress talc. Implemented into plant practice

  • Identified surface interference. Introduced a simple dispersant in grinding for maximising the recovery of fine galena in the Mount Isa Mines Ltd Lead/Zinc Concentrator. Lead concentrate grade and recovery increased from 52.8% Pb at 80.5% recovery to 56.3% Pb at 82.5% recovery with a significant increase in silver recovery to the lead concentrate (>1.5%), and an overall increase in zinc recovery to the final zinc concentrate of 2%.

  • Identification of errant platinum species in refinery liquors for Anglo Platinum; development of diagnostic surface analysis techniques for specific application to platinum group metal flotation and refining; elucidation of flotation processes (specifically relating to Cu activation) leading to incomplete recovery.

  • Identification of the mineralogical location of nickel in ore and leach residues, for Anglo Research, leading to increased pilot plant recovery from 70 % to 96 %.

  • Increased understanding of the mechanisms of crystal growth modifiers in the Bayer cycle (Ondeo-Nalco).

  • Increased understanding of scaling mechanisms in single stream Bayer plants (Cytec Industries).

  • Identification of surface chemical factors leading to poor mineral flotation recoveries for Kennecott Utah Copper Company.

  • Improved strategies for copper recovery from chalcopyrite leaching for Rio Tinto. An international patent, lodged and funded by Rio Tinto (Esdaile, Gerson et al., Recovery of copper from chalcopyrite, WO2003/038137, PCT/AU0/01468, 2003, Australia, Canada, Chile, China, Indonesia, Kazakhstan, Mexico, Russian Federation, United States of America and Zambia) that defined an industrial leach process resulted from research undertaken by CI1 and her team. This then lead to two in-house Rio Tinto research projects ($0.92M, $0.62M) and a column leach study ($1.5M). This formed one of the rationales for a pilot scale feasibility study at a site in Peru ($4.5M) and a larger scale test leach process at Kennecott Utah Copper Corporation, USA.
Sponsoring companies
  • 3M Australia
  • ACI Industrial Minerals
  • Alcoa World Alumina
  • Anglo Platinum Ltd (South Africa)
  • Anglo Research Pty Ltd(South Africa)
  • AMIRA International
  • Billiton Aluminium Australia
  • Birla Nifty Copper Operation (WA)
  • BHP Billiton
  • Comalco
  • Cominco/Teck Alaska
  • Ciba Speciality Chemicals
  • Cytec Industries (USA)
  • Exxaro Mining (South Africa)
  • Kennecott Utah Copper (USA)
  • Mineracao Caraiba (Brazil)
  • Nabalco
  • Newcrest (Australia)
  • Newmont (USA)
  • Ondeo-Nalco
  • OZ Minerals
  • Queensland Alumina
  • Rio Tinto (Australia)
  • Teck Resources (Canada)
  • Tiwest Joint Venture (Kerr McGee/Exxaro)
  • Western Mining Corporation
  • Worsley Alumina
Acid Mine Drainage
Examples
  • Series of 5 AMIRA/ARC Linkage Grants (1997-2017) on assessment and control of acid mine drainage from mining wastes.

  • AMIRA Projects P387A,B with EGi. Sponsors Rio Tinto, BHP Billiton, Placer Pacific, PT Freeport Indonesia, Newcrest Australia, Northern Territory Department of Mines and Energy. Development and validation of the different NAG tests (static, kinetic, sequential) completed. Categorisation of waste rock and tailings materials considerably improved through the removal of a number of uncertainties in the predictive quality of the tests. First defined possible pyrite passivation mechanisms leading to extended lag time to acid appearance and/or slower than expected acid release including armouring, coatings, rimming. Assessed the potential for long-term acid neutralisation from non-carbonate, particularly (alumino)silicate, waste minerals. Production of the AMIRA Acid Rock Drainage Test Handbook with practical methods for assessment of mining wastes widely used by site staff and consultants worldwide.

  • AMIRA P933 Project (Rio Tinto, PT Freeport/McMoran, Oz Minerals, Teck Cominco) extended understanding of pyrite oxidation control, acid production and storage, both short- and long-term, using limestone additions in layered and blended application from both lab and site (including PT Freeport 10 year) trials, developed assay techniques for stored acidity and secondary minerals in different forms in ARD wastes, methods to estimate when long-term acid generation rates are matched by non-carbonate acid neutralisation rates from silicate minerals in ARD wastes and compared long-term reaction sequences in generic ARD waste treatment methods including studies of field samples from sponsor and research partner sites.

  • AMIRA P933A with Boojum Research ( BHPBilliton Iron Ore, Teck Resources, Hidden Valley Services, EPA Tasmania, Grange Resources, Caloundra Environmental) established that acid generation rates (AGR) of pyrite, pyrrhotite and chalcopyrite oxidation are reduced by >90 % by establishing passivating layers of silicate-stabilised iron oxyhydroxides and goethite that restrict access by oxygen and water to the sulfide surface reducing the AGR sufficiently for some reactive silicates to provide matching acid neutralisation rates (ANR) with long-term stability. Measured oxidation rates suggest that these additions blended into surface layers of wastes containing up to 5 wt.% sulfide may result in passivation for many decades. Additional control of the AGR at source has been found with microbial action which reduces oxygen and produces biofilms that add to the passivating layers on pyrite. These results and others from the P933A project have demonstrated that many mining operations have materials available at site which can be used, when assessed and applied appropriately, to reduce the ARD liability of the site. The methods are applicable to sulfidic mine wastes from base metals, coal, iron ore operations and legacy sites.

  • The application of these geochemical principles in reducing AGR and raising pH from 4.5 to 7 has been demonstrated in the Savage River Rehabilitation Project (Tasmania) where on-site neutralising rock was applied to a legacy dump as side covers and flow-through base dumps with verification of the passivating layers on pyrite in the intersection zones.

  • Teck Metals Inc.–Identification mineralogical location of Se in coal wastes and proposal of strategy for treatment.
Sponsoring companies
  • AMIRA International
  • BHP Billiton (Iron Ore, Cannington)
  • Caloundra Environmental P/
  • Environmental Geochemistry Int. (EGi, Sydney)
  • Harmony Mining (Morobe Joint Venture) (Papua New Guinea)
  • Kennecott Utah Copper (USA)
  • MMG/Pasminco
  • Newcrest Australia
  • Northern Territory Dept. Mines and Energy
  • Oz/Zinifex
  • PT Freeport (Indonesia)
  • Rio Tinto (Australia)
  • RGS Environmental Services P/L
  • Savage River Rehabilitation Program (EPA Tasmania)
  • Teck Resources (Canada)



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