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Rehabilitation Standards for the Ranger uranium mineRehabilitation The Ranger uranium mine in the Northern Territory must cease mining and processing activities by 2021, and be rehabilitated by 2026. As the mine approaches the end of its life, the Supervising Scientist will continue to play an important role to protect the environment. Now and into the future.

The Supervising ScientistThe Supervising Scientist was established by the Environment Protection (Alligator Rivers Region) Act 1978. The position is supported by the Supervising Scientist Branch within the Australian Government Department of the Environment and Energy.

The Supervising Scientist undertakes independent scientific research into, and monitoring of, the potential effects of uranium mining in the Alligator Rivers Region.

To ensure the long-term protection of people and the environment, the Supervising Scientist also provides:

• technical oversight of the rehabilitation of the Rangeruranium mine

• advice on the adequacy of rehabilitation plans

• advice on the overall success of rehabilitation once itis completed.

Supervising Scientist’s Rehabilitation StandardsThe Supervising Scientist has developed a series of Rehabilitation Standards against which the success of rehabilitation can be measured.

The standards are based on 40 years of research and monitoring to provide an evidence-based quantification of the Environmental Requirements. They are not mandatory but will form the basis of the Supervising Scientist’s advice on the closure criteria and rehabilitation plans proposed by the mine operator, Energy Resources of Australia (ERA), as well as the eventual success of rehabilitation.

The standards fit into six key rehabilitation themes:

• Radiation

• Water & Sediment

• Ecosystem Restoration

• Soils

• Landform

• Culture.

Images: (banner) Rehabilitation standards will help ensure ongoing protection of aquatic ecosystems in Kakadu National Park © Department of the Environment and Energy.

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Rehabilitation themes

Radiation

The Environmental Requirements for radiation state that radiological conditions on the Ranger site must be stable such that radiation risks to people and the environment are as low as reasonably achievable and do not exceed applicable limits. Two standards for radiation have been released, one to protect people and another to protect the environment:

• The Public Radiation Protection Rehabilitation Standard was developed according to international best practice, including guidelines established by the International Atomic Energy Agency and the International Commission on Radiological Protection.

• The Environmental Radiation Protection Rehabilitation Standard was developed according to the conclusions on radiation exposures and effects to organisms from the United Nations Scientific Committee on the Effects of Atomic Radiation.

Water and sediment

The Environmental Requirements require ongoing protection of the biodiversity and health of aquatic ecosystems outside the Ranger Project Area. To achieve this, the Water and Sediment Rehabilitation Standards provide concentrations for key chemical contaminants, and levels for turbidity and sedimentation, which will protect the environment. The limits set in the standards have been derived using site-specific data wherever possible, following the advice contained in the Australian and New Zealand guidelines for fresh and marine water quality (ANZECC & ARMCANZ 2000).

A rehabilitation standard is not currently planned for groundwater. The need for a groundwater standard will be reviewed as further information is acquired. Current assessments of groundwater quality are based on the extent to which contaminants in groundwater may affect surface water quality.

Supervising Scientist tests bushfoods for the presence of radionuclides © Supervising Scientist.

Images: (clockwise from top) A primary objective of rehabilitation is to return Ranger mine site to an environment that is similar to the surrounding Kakadu National Park © Tourism NT. Moinodaphnia macleayi, one of the tropical freshwater species used to test water quality © Supervising Scientist. Aerial view of the wetlands, Supervising Scientist Branch monitors turbidity of waterbodies around the mine © Supervising Scientist.

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Ecosystem Restoration

The Environmental Requirements state that a sustainable ecosystem must be established on the disturbed areas of the Ranger Project Area that it is similar to the surrounding areas of Kakadu National Park. Stable ecological processes and local vegetation must be established to underpin colonisation by animals and provide for appropriate species abundance and diversity of plants and animals. The Ecosystem Restoration Rehabilitation Standard is based on the National standards for the practice of ecological restoration in Australia produced by the Society for Ecological Restoration Australasia. It includes guidelines for plant and animal community structure, and measures of sustainability and resilience to threats such as fire, weeds and feral animals. Key measures contained in the Rehabilitation Standard will be informed by vegetation data gathered from large-scale vegetation surveys undertaken by drones.

Culture

The Environmental Requirements state that throughout all mine operations, including rehabilitation, the cultural World Heritage values of Kakadu National Park must be maintained. The views of the Mirarr traditional owners of the Ranger Project Area have been considered in the development of all the rehabilitation standards.

The Supervising Scientist has not produced a cultural rehabilitation standard. Rather, specific cultural closure criteria have been developed collaboratively by the Mirarr and ERA.

Soils

If the Environmental Requirements for ecosystem establishment are to be achieved, levels of contaminants in soils will need to be low enough to ensure there are no impacts on soil organisms and plants. Rather than develop rehabilitation standards for contaminants in soils, the Supervising Scientist will rely on independent peer review of the soil quality closure criteria proposed by ERA. The soil quality closure criteria will need to be consistent with the National Environment Protection (Assessment of Site Contamination) Measure 1999 (amended May 2013), unless more recent and rigorous information is available.

The rehabilitated mine site must have similar populations of plants and animals as the surrounding park, and be a fully functioning ecosystem © Department of the Environment and Energy and Brian Furby.

Culture is an overarching theme of Ranger mine rehabilitation © Department of the Environment and Energy.

Soil contamination levels must not impact on soil organisms or plants © Supervising Scientist.

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Landform

The Environmental Requirements state that the rehabilitated landform must be stable and have erosion characteristics which, as far as can reasonably be achieved, do not vary from those of comparable landforms in surrounding undisturbed areas. The buried tailings must be physically isolated from the environment for at least 10,000 years. By meeting this standard, erosion rates on the landform will not exceed those that would result in the exposure of tailings and will approach background over time. The standard is based on the Queensland Government guideline, Rehabilitation requirements for mining resource activities, and is underpinned by a leading-practice erosion model. The potential biological effects of turbidity are considered under the Water and Sediment theme.

The Regulatory Framework

Environmental Requirements

Operations at the Ranger uranium mine, located in the Ranger Project Area, are governed by Commonwealth and Northern Territory laws and regulations, particularly:

• Section 41 Authority issued under the Atomic Energy Act 1953 (Cwlth)

• Ranger Authorisation issued under the Mining Management Act (NT).

The Environmental Requirements, which stipulate how the Ranger mine is to be operated, rehabilitated and closed, are attached to both the s.41 Authority and the Ranger Authorisation.

At Ranger uranium mine, under the s.41 Authority:

• all mining and processing must cease by January 2021

• major rehabilitation works must be completed by January 2026.

Modelling showing the post-mining surface of the Ranger disturbed area (Mt Brockman in background) © Supervising Scientist.

Ranger uranium mine in the Northern Territory © Supervising Scientist.

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© Commonwealth of Australia, 2018.

This fact sheet is licensed by Commonwealth of Australia under a Creative Commons Attribution 4.0 International licence.

The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment and Energy.

Rehabilitation objectives

Objectives listed in the Environmental Requirements must be achieved through rehabilitation:

• Rehabilitate the Ranger uranium mine to establish an environment that is similar to the surrounding Kakadu National Park, such that it could be incorporated into the Park.

• Ensure there is no change to biodiversity, or impairment of ecosystem health, outside of the Ranger Project Area as a result of mine operations.

• Maintain the cultural and natural World Heritage values of Kakadu National Park.

• Ensure stable radiological conditions that comply with applicable limits, and which are as low as reasonably achievable and do not pose a risk to people or the environment.

• Ensure erosion characteristics of the final landform do not vary significantly from those of comparable landforms in surrounding undisturbed areas.

Ranger mine closure process

Closure criteria

ERA has proposed closure criteria for the Ranger uranium mine in its Mine Closure Plan.

The proposed closure criteria will become mandatory after they are approved by the Australian Government and Northern Territory Government ministers, who both consider the advice of the Supervising Scientist. Once approved, these criteria will be used to judge when the Environmental Requirements have been achieved, and the site can be closed.