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Environment Protection (Alligator Rivers Region) Act 1978

Section 36 of the Environment Protection (Alligator Rivers Region) Act 1978 requires the Supervising Scientist to provide to the minister an annual report on the operation of the Act. This section provides the report for the period from 1 July 2019 to 30 June 2020.


The position of the Supervising Scientist is established under the Act for the purpose of protecting the Alligator Rivers Region from the effects of uranium mining.

The Supervising Scientist Branch is funded under the portfolio’s departmental appropriation and contributes to the delivery of Outcome 1: Conserve, protect and sustainably manage Australia’s biodiversity, ecosystems, environment and heritage through research, information management, supporting natural resource management, establishing and managing Commonwealth protected areas, and reducing and regulating the use of pollutants and hazardous substances, and coordination of climate change adaptation strategy and climate change science activities.

The activities of the Supervising Scientist under the Act help to achieve this objective by determining whether there has been detrimental impact to the people and the environment of the Alligator Rivers Region, including Kakadu National Park, as a result of uranium mining activities.

Ministerial directions

Under section 7 of the Act, the Supervising Scientist is required to comply with any directions given by the minister relating to the performance of functions or the exercise of powers. In 2019­–20 the minister did not issue any such directions to the Supervising Scientist.

Collection and assessment of information

This report summarises information on the environmental effects of uranium mining collected and assessed throughout 2019–20 in accordance with section 36(2)(b)(i) of the Act. Further details are provided in the Supervising Scientist Annual Technical Report, which is published on our website.

We work to protect the environment of the Alligator Rivers Region, including Kakadu National Park, from the effects of uranium mining activities. We work with Commonwealth and Northern Territory regulatory authorities, and in consultation with traditional owners through the Northern Land Council and the Gundjeihmi Aboriginal Corporation, to develop and implement programs to measure the effectiveness of environmental management at uranium mining and exploration sites. These programs include supervision, monitoring and environmental research.

The focus of most of the Supervising Scientist’s activities in recent years has been on the Ranger uranium mine – the only operating uranium mine in the region. Among our broader responsibilities in the region (Table 41), Ranger presents the most significant environmental risks, during both mine operations and rehabilitation.


Our supervision program includes a structured plan of assessments, inspections and audits which provide a mechanism for reviewing and assessing the performance of environmental management systems in place at various mine and exploration sites. Throughout 2019–20 this program was focused on 5 main areas within the region, including Ranger mine, 2 historical mine sites in various stages of rehabilitation and several exploration sites.

Table 41 Summary of supervision activities at 5 sites in the Alligator Rivers Region, 2019–20





South Alligator Valley

West Arnhem exploration

Meetings of the mine site technical committee




Applications assessed


Non-routine reports assessed



Routine reports/plans assessed





Applications under assessment


Authorisation amendments assessed


Environmental audits


0 a

Environmental inspections

9 b





Incidents reported

23 c

a The audit program for Jabiluka has been suspended, as the site is in long-term care and maintenance. b The March 2020 and April 2020 routine inspections were cancelled due to restrictions associated with the COVID-19 pandemic. c All reported environmental incidents were followed up through the routine inspection program. N/A Not applicable


Our monitoring program uses a multiple-lines-of-evidence approach, assessing chemical, biological and radiological indicators to detect short-term and long-term impacts of mining on the people and environment surrounding Ranger mine.

The key pathway for exposure of contaminants to the environment during the operational phase of the Ranger mine is the surface water pathway. To ensure the protection of people and the environment, the mine’s operator, Energy Resources of Australia Ltd (ERA) is required to achieve specific water quality objectives for the creeks surrounding the mine. These water quality objectives are largely based on site-specific biological effects data, and their achievement provides a key line of evidence that the environment has been protected.

Surface water chemistry data show there were no exceedances of the Ranger water quality objectives throughout the 2019–20 wet season. For example, concentrations of uranium in surface water downstream of Ranger remained below 2.8 μg/L throughout the 2019–20 wet season.

Biological monitoring techniques have been developed that can be used for both early detection monitoring and assessment of long-term ecosystem-level responses. Results of the in-situ biological toxicity monitoring (early detection) and fish and macroinvertebrate monitoring (long-term detection) showed that downstream biodiversity had been protected, based on the data that had been analysed at 30 June 2020.

One of the main pathways of potential radiation exposure to the public during Ranger operations is the ingestion pathway, caused by the uptake of radionuclides into bush foods from creek systems downstream of the mine. Freshwater mussels have previously been identified as the most important food source contributing to radiation dose to people, as they strongly bio-accumulate radium-226 in their flesh. Mussels were collected from Mudginberri Billabong, downstream of Ranger, in October 2019 and analysed for radium-226 as part of the routine bioaccumulation monitoring program. Results indicate that radium-226 concentrations had not increased as a result of uranium mining and that there is no unacceptable radiation risk from consuming mussels as part of a bush food diet.

In summary, all monitoring undertaken to date indicates that there have been no observable environmental impacts from Ranger mine’s operations and that the people and the environment of the Alligator Rivers Region remained protected from the effects of uranium mining during 2019–20. A detailed description of all results obtained from the 2019–20 monitoring program will be published in the 2019–20 Supervising Scientist annual technical report.

Environmental research

During 2019–20, our research was directed at gaining information to assist with managing key environmental risks associated with Ranger mine operations and rehabilitation. The number of research projects for this period is shown in Figure 29.

Our proposed research program for 2019–20 built on the approach developed since 2017, which has been underpinned by a comprehensive risk-based planning process to map out our research priorities and associated key knowledge needs over the next 5 years. The Alligator Rivers Region Technical Committee is established under the Act to independently review research into the effects of uranium mining in the Alligator Rivers Region. The Technical Committee endorsed the 2019–20 research program in May 2019.

The 2019–20 research program comprised 39 research projects. Rehabilitation research associated with water and sediment quality, ecosystem restoration and landform dominates our efforts. Over the next 5 years, Ranger rehabilitation research will decline as key knowledge needs identified for the research themes shown in Figure 29 are progressively acquired.

In 2019–20 we published the findings and outcomes of these projects in 13 peer-reviewed articles. Transparent and succinct advice arising from research project work undertaken is also communicated to Ranger mine stakeholders through a series of technical advice memoranda, 9 of which were produced in 2019–20.

Figure 29 Research projects by research theme, 2019–20 A column graph showing the number of research projects by research theme in 2019-20. There were 18 projects for the theme Water and sediment. There were 12 projects for the theme Ecosystem restoration. There were 8 projects for the Landform theme. There were 7 projects for the Radiation theme. There were 2 cross-theme projects.

Standards, practices and procedures

We adopted or amended standards, practices and procedures during 2019–20 in accordance with section 36(2)(b)(ii) of the Act:

  • We developed a suite of rehabilitation standards for Ranger mine, which was published in the third quarter of 2018. These and subsequently published standards, and their refinement, provide quantitative values against which the mine operator’s proposed closure criteria can be assessed.
  • We are developing procedures and methods for collecting and processing remotely piloted aircraft system data to derive standards for revegetation, as well as restored ecosystem monitoring. The refinement of these methods and procedures over time will reduce or eliminate the need for ground-based resource-intensive field surveys.
  • The chronic toxicity testing method for the northern trout gudgeon, Mogurnda mogurnda, was further improved and is being used for routine testing. The protocol has been submitted for peer-review.
  • Development is under on remote videography methods for monitoring fish communities in channel and shallow lowland billabongs as a replacement technique for trapping or visual counts. These methods significantly reduce the risks associated with working in crocodile-inhabited waters. We are collaborating with Microsoft to develop artificial intelligence models to automate the counting and identification of fish in the videos.
  • We are constructing a database of genome sequences which will be used to increase the accuracy, safety and efficiency of annual macroinvertebrate surveys.
  • We implemented new software and procedures for radioactivity analysis of environmental samples by gamma spectroscopy, ensuring ongoing capability to detect and measure radioactivity in the environment from both natural and mine-derived sources.

Protection and restoration measures

We implemented environmental protection and restoration measures in accordance with section 36(2)(b)(iii) of the Act in 2019–20:

  • The Ranger mine operator, ERA, submitted an updated version of its Ranger Mine Closure Plan in October 2019. The plan includes proposed closure criteria for Ranger mine to apply on and off site after rehabilitation. We assessed the plan, publishing an assessment report online in December 2019.
  • We successfully completed the annual routine water quality and biological monitoring programs.
  • We successfully completed the annual audit and routine inspection program.
  • We continued ongoing monitoring of the adequacy and effectiveness of remedial works undertaken by the mine operator.

Requirements of prescribed instruments enacted, made, adopted or issued

In 2019–20, no prescribed instruments were enacted, made, adopted or issued under section 36(2)(b)(iv) of the Act.

Implementation of requirements

We continued to oversee and supervise the implementation of the Atomic Energy Act 1953 and the Northern Territory Mining Management Act 2001 as they relate to Ranger uranium mine.

Cost of operations

The cost of operations for the Supervising Scientist in 2019–20 was $7,912,918.