Assessing discharges from a uranium mine — case study

​​​​​Water used in mining can adversely affect the quality of the surface water and groundwater surrounding the mine. Assessing water discharges from mines is important to ensure compliance with licence conditions and, ultimately, to ensure environmental protection.

About the site

Ranger mine is located on the 79 km2 Ranger Project Area 260 km east of Darwin, Northern Territory. The site is surrounded by, but separate from, the World Heritage listed Kakadu National Park.

The Ranger Project Area is part of the Alligator Rivers Region, which includes the catchments of the West, South and East Alligator rivers. It contains high conservation, high ecological value aquatic ecosystems in its surrounding waterways.

Discovered in 1969 and first opened in 1980, the Ranger mine is owned by Energy Resources of Australia Limited, a subsidiary of Rio Tinto. Uranium mined at Ranger provides nuclear power in Asia, Europe and North America. Mine operations have reduced to processing of stockpiled uranium oxide ore since open-cut mining ceased in 2012.

Applying the Water Quality Management Framework

After more than 30 years in operation, the Ranger mine operator and regulators have undertaken many water quality assessments. These assessments represent multiple cycles through the Water Quality Management Framework.

This case study focuses on a more recent issue to assess mine waters with high levels of magnesium sulfate (MgSO4) and their discharge into an adjacent waterway, Magela Creek.

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References

Hogan AC, Trenfield MA, Harford AJ & van Dam RA 2013, Toxicity of magnesium pulses to tropical freshwater species and the development of a duration-based water quality guideline, Environmental Toxicology and Chemistry 32: 1969–1980.

Iles M 2004, ‘Water quality objectives for Magela Creek — revised November 2004’, internal report no. 489, Supervising Scientist, Darwin.

O’Connor R, Humphrey C, Dostine P, Lynch C & Spiers A 1995, ‘A survey of aquatic macroinvertebrates in lentic waterbodies of Magela and Nourlangie Creek catchments, Alligator Rivers Region, Northern Territory’, internal report no. 225, Supervising Scientist, Darwin.

O’Connor R, Humphrey C, Lynch C & Klessa B 1996, ‘A survey of macroinvertebrates in lentic waterbodies of Magela and Nourlangie Creek catchments, Alligator Rivers Region, NT: second year of data’, internal report no. 242, Supervising Scientist, Darwin.

Sinclair A, Tayler K, van Dam R & Hogan A 2014, Site-specific water quality guidelines: 2. Development of a water quality regulation framework for pulse exposures of mine water discharges at a uranium mine in northern Australia, Environmental Science and Pollution Research 21: 131–140.

Supervising Scientist 2009, ‘Annual Report 2008–2009’, Supervising Scientist, Darwin.

Supervising Scientist 2016, Ranger Mine Monitoring Data,​ Department of the Environment and energy website, Supervising Scientist, Darwin, accessed 23 June 2016.

van Dam RA, Hogan AC, McCullough CD, Houston MA, Humphrey CL & Harford AJ, 2010, Aquatic toxicity of magnesium sulfate, and the influence of calcium, in very low ionic concentration water, Environmental Toxicology Chemistry 29(2): 410–421. ​

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