Supervising Scientist Division

Supervising Scientist Annual Report 2003 - 2004: Other activities in the Alligator Rivers Region

Supervising Scientist, Darwin, 2004
ISBN 0 642 24391 3
ISSN 0 158-4030

2 - Environmental assessments of uranium mines (continued)

2.5 Other activities in the Alligator Rivers Region

2.5.1 Historical tailings adjacent to the Gunlom Road

During 2003-04, oss provided technical advice to assist Parks Australia North (PAN) manage the area (the tailings area) adjacent to the Gunlom Road where uranium mill tailings from historical mining and milling activities conducted in the 1950s and 1960s had been deposited. oss implemented a programme of inspections focusing on issues such as radiological protection, fire, weed and erosion control in accordance with the agreed protocol. These activities focused on the tailings area, which had been stabilised with a rock cover to minimise erosion in 2000, and the small compound nearby where contaminated soil from the side of the Gunlom Road had been placed in 2000. Both of these sites were well managed by PAN.

2.5.2 Rehabilitation of the South Alligator Valley uranium mines

Discussions with Traditional Owners were carried out during the reporting period by oss, PAN and NLC staff to seek approval to drill at two potential final containment locations to determine groundwater conditions as a requirement of any licence issued by ARPANSA for the final containment site. Agreement was reached with Traditional Owners to undertake limited shallow drilling at the South Alligator Village site and the South Alligator Valley Airstrip site. These two locations were identified by consultants EWLS as the preferred locations based on landform stability and a low risk of flooding. The drilling programme should be completed towards the end of August 2004. After that, boreholes will be monitored over the next few season to help decide on the preferred containment location.

There was no further progress on actions from Part A of the South Alligator Rehabilitation Plan during the reporting period and it is unlikely that any works other than the drilling programmes will occur before the 2004-05 wet season.

oss continued a programme of inspections of the Gunlom Road site and the container storage facility during the reporting period. All inspections have had satisfactory outcomes with no actions required. The firebreak at the container storage site was cleared by PAN staff early in the dry season as requested.

During an early dry season visit, oss staff supervised installation of monuments marking the temporary containment sites of old mining infrastructure in the South Alligator Valley. It is anticipated that the monuments will remain there until the final containment site is constructed and all materials moved to this site. Once this is completed, the monuments will be moved to the final containment site where they will delineate the extent of the containment.

2.5.3 Exploration

Figure 2.20: Cameco Australia Pty Ltd drilling rig, King River exploration campaign - June 2004

Figure 2.20: Cameco Australia Pty Ltd drilling rig, King River exploration campaign - June 2004

The Office of the Supervising Scientist coordinated a programme of site inspections at exploration sites during 2003-04. These sites were in West Arnhem Land where Cameco Australia Pty Ltd is exploring for uranium.

The inspections took place in July and August 2003, and again in June 2004. The August 2003 inspection team included representatives from oss, NLC and DBIRD. The exploration campaign visited by the team was based at the Myra Falls camp site, which had been inspected earlier in the season. The team checked the completion of an earlier heli-borne programme followed by the current terrestrial drilling programme. The team also inspected the site of a 200 L diesel fuel spill and found the clean up satisfactory. The team inspected the drilling programme at an operational site and viewed former drill sites and roads awaiting preparation for final rehabilitation and noted minimal environmental impact from the work. In particular, the team noted the use of liners in sumps and a high level of cleanliness at the active rig. The team examined cleared lines for RAB (rotary air blast) drilling, noting how the ground disturbance had been minimal with paths weaving around trees and no felling of trees. A small number of former drill sites up to three years old were examined to see how well rehabilitation was proceeding. The time taken to locate one of these sites is an indication of rehabilitation success. There was no change to the campsite since the earlier (July) inspection. No issues arose for discussion from any part of the inspection.

A further inspection took place in June 2004. The team visited the King River camp to inspect the campsite and nearby active drilling pads. No issues were identified. The team also visited a number of former drill and RAB lines nearby and located sites one, two and three years old as well as an older Afmex site. All sites were generally rehabilitating in accordance with expectations given their respective ages. Using a GPS made finding the sites easier but some sites more than two years old were still hard to identify.