Assessment of ecological impacts arising from incidents at the Ranger and Jabiluka mines

Assessment of ecological impacts arising from incidents at the Ranger mine from 1979 to June 2008
Assessment of ecological impacts arising from incidents on the Jabiluka Project from 1996 to June 2008

Assessment of ecological impacts arising from incidents at the Ranger mine from 1979 to June 2008

There have been more than 145 incidents and events reported at the Ranger mine since operations began. The rules for reporting such incidents have varied over the life of the mine but the current system under the Environmental Requirements (ER) has been in force since 1 January 2000, and states that:

The company must directly and immediately notify the Supervising Authority, the Supervising Scientist, the Minister and the Northern Land Council of all breaches of any of these Environmental Requirements and any mine-related event which:

results in significant risk to ecosystem health; or
which has the potential to cause harm to people living or working in the area; or
which is of or could cause concern to Aboriginals or the broader public.

The Supervising Scientist has investigated every such incident and, with two exceptions, has concluded that there has been no significant environmental impact at the time of the incident nor any lasting environmental detriment.

Two significant incidents associated with mining operations at Ranger occurred in 2004. These incidents involved the contamination of the mine's potable water supply and the release of contaminated earthmoving equipment from the minesite without adequate radiation clearance procedures having been followed. Both were investigated in detail by the Supervising Scientist with the respective investigation reports having been made publicly available:

Supervising Scientist 2004. Investigation of the potable water contamination incident at Ranger mine March 2004. Supervising Scientist Report 184, Supervising Scientist, Darwin NT.

Download SSR184

Supervising Scientist 2004. Investigation of radiation clearance procedures for vehicles leaving the Ranger mine . Supervising Scientist Report 185, Supervising Scientist, Darwin NT.

Download SSR185

Investigations concluded that while both triggered the Environmental Requirement criteria for reporting, neither of these two incidents resulted in any significant environmental impact.

On what basis was this assessment of environmental significance made?

The Supervising Scientist has developed a simple matrix to explain the basis used for assessing ecological significance.

The significance of an ecological impact may be considered in terms of two issues:

how severe the impact is, and
how long it lasts.

Assessment of impact severity is based on the actual damage to the ecosystem or landscape.

In the matrix, there are 5 categories of impact severity ranging from 'no detectable change' in the physical, chemical or biological variables that characterise the environment through various categories to one in which change occurs 'at the ecosystem level'.

Duration of impact is classified (in increasing significance) from <1 month to indefinite.

An incident's position in the matrix gives us a technical description (shown in the cell labels) of its environmental impact. The number of incidents that match each of these classifications is recorded in each cell.

Assessment of ecological impacts arising from incidents at the Ranger mine from 1979 to June 2008
	Duration of impact
Severity of impact	Less than 1 month	Less than 1 year (less than a complete seasonal cycle)	Within project life (estimate no. of years to recovery)	Indefinite
Change at the ecosystem level	Brief serious impact 0	Short term serious impact 0	Extended serious impact 0	Long-term serious impact 0
Mortality within some species	Brief moderate impact 1*	Short term moderate impact 0	Extended moderate impact 0	Long-term moderate impact 0
Stress or behavioural change to individuals	Brief mild impact 0	Short term mild impact 0	Extended mild impact 0	Long-term mild impact 0
Physical or chemical changes only	Brief non-biological impact 15	Short term non-biological impact 0	Extended non-biological impact 0	Long-term non-biological impact 0
No change detectable	No impact 129	No impact 0	No impact 0	No impact 0
* Bird kill in RP2 in December 1995

The cell shading represents the Supervising Scientist's view of how the significance of environmental impacts should be regarded in the Alligator Rivers Region.

Darker shaded cells describe ecologically significant impacts that require immediate intervention.
Lighter shaded cells represent impacts of moderate environmental significance which do not meet community expectations on mining company performance and require remedial action
No shading represents impacts considered to have no significance to ecosystem health or conservation values of the region

The ecological significance of the 145 incidents reported since 1979 has been assessed by the Supervising Scientist within this framework. Most incidents have resulted in no ecological impact. Some, including minor tailings spills, fall into the 'brief non-biological impact' category.

Two incidents were significant:

One incident (5 July 1982) involved the health and safety of two workers in the packing plant. Following the incident, the Supervising Scientist undertook a specific study of radiation safety standards at Ranger and submitted a special report to the Minister for the Environment on 11 November 1983. The Supervising Scientist concluded that some radiation protection procedures at Ranger could be improved but, despite some reservations about training, assessed that radiation exposures of workers during routine operations were likely to have been below the appropriate regulatory dose limit.
The second significant incident resulted from a spill of diesel from tanks at the power station at Ranger followed by drainage into Retention Pond 2 on 6 December 1995. This resulted in the death of 40 water birds. The Supervising Scientist concluded that this was the first unacceptable environmental impact that had arisen as a consequence of operations at Ranger. This impact occurred on the Ranger Project Area, however, not in Kakadu National Park.

Summary

No incident, in the opinion of the Supervising Scientist, has led to significant ecological impact. Of the total of 145 incidents that have been reported since mining began at Ranger in 1979, only one incident has been assessed as being of moderate ecological significance and one incident has had significant impact on people working at the mine.

While the list of incidents reported appears large, this is a reflection on the rigour of the reporting framework and not a reflection on the standard of environmental performance at the Ranger mine.

Assessment of ecological impacts arising from incidents on the Jabiluka Project from 1996 to June 2008

There have only been 2 reportable incidents at Jabiluka over the life of the project to date. The Supervising Scientist has investigated both incidents and has concluded that there has been no significant environmental impact at the time of the incident nor any lasting environmental detriment.