Closure and rehabilitation process
Mining operations cause significant environmental disturbance, and if not managed appropriately may have detrimental impacts. Rehabilitation of disturbed sites is the process of returning the land to an acceptable state depending on the agreed values and end land use. Rehabilitation typically occurs in multiple stages and can take many years to complete.
Aerial view of the rehabilitation and vegetation regrowth on the Jabiluka minesite from 2006 to 2018
In accordance with current approvals, Energy Resources of Australia (ERA) must cease processing of uranium ore at Ranger mine by 2021, and complete all decommissioning and rehabilitation works by 2026.
In the years after 2026 an ongoing effort will be required to ensure that the rehabilitation is successful. This will include: monitoring to ensure the rehabilitated site is on a suitable trajectory towards closure and completion criteria and to detect environmental impacts; the control of weeds and management of erosion; and, the exclusion of fire during the early stages of vegetation establishment. Over time, the requirement for post-rehabilitation management activities will reduce until, eventually, the site no longer needs active management, at which point it may be suitable for permanent closure.
ERA is responsible for rehabilitation of the Ranger Project Area. The stringent environmental objectives stipulated by the Australian Government require the site to reach a state that is similar to the adjacent area, such that it could be incorporated into Kakadu National Park should that be decided in the future.
Role of Supervising Scientist in Ranger rehabilitation
Established in 1978, the Supervising Scientist plays an important part in ensuring that people and the environment in the Alligator Rivers Region remain protected from the effects of uranium mining, both now and in the future.
The Supervising Scientist’s role is to monitor to detect environmental impacts that may occur during and after the rehabilitation of Ranger uranium mine, and to undertake research to address knowledge gaps related to mine rehabilitation. The role includes providing independent scientific advice to Government on all aspects of the rehabilitation, including best practice regulatory processes.
Our research includes assistance to ERA in the development of appropriate closure criteria for the rehabilitated site and the offsite environment. To this end, the Supervising Scientist has developed and recently published Rehabilitation Standards that set targets for restoration and closure of the site. The Standards describe the requirements for:
- Protection of aquatic ecosystems outside of the Ranger Project Area from adverse effects of contaminants
- Restoration of the terrestrial ecosystem and long-term stability of the final reconstructed landform
- Radiation protection for members of the public and aquatic and terrestrial ecosystems
The development of monitoring programs, together with specific research project work and techniques for data acquisition, for rehabilitation are described under Environmental Research. These rehabilitation-related projects are underpinned by the Ranger Rehabilitation Key Knowledge Needs developed by SSB in consultation with ERA and the Alligator Rivers Region Technical Committee.
Energy Resources of Australia Ltd (ERA) rehabilitation sign
The Environmental Requirements of the Commonwealth of Australia for the Operations of the Ranger Uranium Mine (Australian Government 1999) stipulate the environmental objectives for the Ranger mine, aiming to ensure that the activities of ERA on the Ranger Project Area do not impact upon the values, attributes and ecosystem health of Kakadu National Park, nor the health of the regional community.
Ranger Mine Closure Plan and Assessment
In 2018, ERA publicly released its Ranger Mine Closure Plan detailing the approach to the progressive rehabilitation of Ranger mine over the next decade. The Closure Plan will be updated each year. Following a detailed technical assessment of the Plan by the Supervising Scientist, recommendations were provided to relevant Australian and Northern Territory Government ministers, to inform decisions regarding approval of the Plan.
East Alligator River in Kakadu National Park, NT
Following the release of the Ranger Mine Closure Plan, the Supervising Scientist has released its Ranger Mine Closure Plan Assessment Report. This assessment report constitutes advice to the ministers as to whether the implementation of the plan will result in achievement of the major rehabilitation objectives set out in the ERs.
Key Knowledge Needs
The Key Knowledge Needs (KKNs) articulate the relevant knowledge required to ensure:
- the environment and people of the Alligator Rivers Region are protected from the impacts of uranium mining; and
- upon reaching end-of-life, uranium mines in the Alligator Rivers Region are rehabilitated to the standard required by the Commonwealth and the community.
The KKNs encompass the knowledge needs for all past, present and prospective uranium mining activities in the ARR. However, the focus at present remains on the rehabilitation of the Ranger uranium mine.
The KKNs are based upon a comprehensive ecological risk assessment, and provide the basis of the Supervising Scientist and ERA’s environmental research programs.
The KKNs were reviewed and consolidated in 2018. All research projects undertaken by the Supervising Scientist aim to address the KKNs. As the required research is completed each of the KKNs will be progressively closed out.