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