Address: Main Office: John Gorton Building

Results

During the 2010–11 wet season, the maximum total uranium concentration measured downstream from the Ranger mine was 1.01 micrograms per litre, a value consistent with the relative filterable uranium concentration results from previous years. This value is approximately 17 per cent of the local ecotoxicologically-derived limit of six micrograms per litre, and approximately five per cent of the 20 micrograms per litre guideline for drinking water.

Case study 5: Supervising Scientist water chemistry monitoring program for the Ranger mine

The Ranger uranium mine, located 250 kilometres east of Darwin, is completely surrounded by, but excluded from, the World Heritage listed Kakadu National Park in the Northern Territory (see Alligator Rivers Region map on page 77).

The Supervising Scientist Division (SSD) conducts a comprehensive water quality monitoring program as part of its role in protecting the Ramsar-listed Magela Creek wetlands downstream of the Ranger mine, and the people who live there.

The monitoring program has been developed over a number of years, progressively incorporating improved methods and state-of-the-art technology. The program’s successful development is one example of SSD’s capability for developing leading practice methods for assessing the impacts of uranium mining on the environment. The program consists of direct measurements of water quality as well as comprehensive biological monitoring of the aquatic ecosystem.

Manual grab sampling technique (above left). Automated continuous monitoring pontoon, showing solar panels and automatic water sampling units (above right).

SSD’s formal water chemistry monitoring program was first initiated in the 2000–01 wet season.

Between 2000 and 2005, weekly grab samples were collected from sites upstream (control) and downstream (potential impact) of the mine. Grab sampling continued for a further five years (up to the 2009–10 wet season) as the primary water chemistry monitoring method. Starting in the 2003–04 wet season, SSD began to develop a continuous (near real-time) monitoring method that was superior to the grab sampling method. In-field sensors were installed to monitor turbidity (a measure of the cloudiness of the water), electrical conductivity (a measure of the concentration of salts dissolved in the water), and pH (a measure of acidity). Rainfall and water level (a measure of flow) were also recorded. The measured data was stored at 10-minute intervals in data loggers—uploaded via the mobile phone network and downloaded remotely each day from Darwin. The evolution of the monitoring program enabled the introduction of a comprehensive system of SMS-based early warning alarms to notify key operations staff of equipment malfunctions or any significant deviations in water quality.

This continuous measurement of key water quality indicators provides a much more complete record of water quality in the system by capturing transient fluctuations in water quality that would not be detected by grab sampling (see Figure 1).

Figure 1. Electrical conductivity (EC) data from the upstream (blue – us) and downstream (green – ds) sites in Magela Creek for the 2010–11 wet season. The EC values (diamonds) for grab sample are overlaid for comparison on the continuous monitoring data (lines).

During the five-year period of development of the continuous monitoring program, there was regular engagement with stakeholders to communicate the results and develop a shared understanding of the power of this method compared with weekly grab sampling.

Starting with the 2010–11 wet season, the continuous monitoring method, incorporating event-based collection of water samples (fully automated using installed automatic sampling units), replaced the grab sampling method for measuring water quality.

The validated monitoring data is posted weekly on the SSD website. The data plots are accompanied by explanatory notes that give additional interpretative information and discuss any occurrences of note.

Evaluation

During 2010–11 the Supervising Scientist Division continued to conduct research, monitoring, supervision and audit activities. Following trials, further research and statistical testing of the continuous monitoring program over the previous five wet seasons from 2005–06 to 2009–10, SSD successfully implemented continuous monitoring of Magela Creek as the mainstay of its monitoring program during the 2010–11 wet season. This, combined with the refinement over the last few years to the in situ biological monitoring program, has provided stakeholders with a greater level of information about potential mine site impacts on the surrounding aquatic environment. The continuous monitoring program has been particularly well received by stakeholders, and as a subsequent outcome the mining company ERA has instigated a similar program within Magela Creek.

The 2010–11 wet season was one of the wettest on record. As a result, process water storage on-site at Ranger approached maximum operating levels. The mining company ERA then halted processing to ensure that engineering freeboards were not compromised in the Tailings Storage Facility. Processing resumed in June 2011.

All findings to date indicate that the environment of the Alligator Rivers Region remains protected from the impacts of uranium mining. Detailed performance results are provided in the Supervising Scientist’s annual report on the operation of the Environment Protection (Alligator Rivers Region) Act 1978.

Parks Australia Division

Main responsibilities for this outcome

The Director of Parks Australia also manages the Australian Biological Resources Study (ABRS) and the development of Australian Government policy on management of Australia’s genetic resources, including regulating access to such resources in Commonwealth areas, and provides coordination and leadership in meeting Australia’s commitments under the Convention on Biological Diversity. The ABRS is responsible for collecting and disseminating information on Australian plants, animals and other organisms and where they occur. ABRS taxonomic work includes naming, describing and classifying Australia’s biodiversity and managing databases that provide national references for species names. The program funds research and training in taxonomy, as it is critical for biodiversity conservation, biosecurity and a range of industry uses such as agriculture, horticulture, and forestry that species are accurately named and their relationships are understood.