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Water Treatment Evolution

Gold Resource Trial

Water Treatment Goals

  • Treat Acid Mine Drainage (AMD) contaminated water, part of the development of a new zero harm gold resource within an existing polymetallic mine
  • Protect surrounding environmentally sensitive alpine area of Tasmania
  • Comply with legislative requirements and stringent environmental standards
  • Handle issues of site footprint, extreme peak flow events from heavy rainfall, and remote location.

Solutions developed

  • An assessment of existing technologies indicated these were unlikely to achieve the clients environmental goals
  • Ozofractionative Catalysed Reagent Addition (OCRA) process was developed and patented;
  • Design, installation and operation of customised plant with mean daily flow rate of 30.5 kL per day.

Highlights

  • Peak flow of over 1.2M litres per day achieved during high rainfall events – the plant remained within discharge limits at all times.
  • During test of 10L/s for 2 hours 45 minutes source pH of 6.91, post OCRA recorded at 9.84 without addition of reagent (100kL treated),
  • General increase of mean influent of 5.4 to 9.2 (alkaline) with increase in oxidation state of fluid – once introduced to stable precipitant reagent all target contaminant species significantly reduced to less than 5% of influent values,
  •  Increased oxidation of fluid allows increased reagent reaction efficiency, reducing reagent use by nearly 76%, and
  • Many non target species such as oil and grease directly oxidised to less invasive constituent species.

Competitive advantages over traditional AMD treatment methods

  • Favorable capital costs,
  • Reduced operational footprint,
  •  Reduced operational costs,
    • Lower energy consumption
    • Lower reagent consumption
    • Increased production rates, varying with contaminant loads
  • Treatment solution to a broader spectrum of contaminants (inorganic and organic contamination),
  • Ability to control process to meet high standard discharge limits, and
  • Greatly reduced post-treatment sludge costs.

Download Acid Mine Drainage Case Study (PDF 502 KB)