Radiation surveys of El Sherana camp site and Sleisbeck pit and waste rock piles

1998

Internal Report 284
Tims S & Ryan B
Supervising Scientist Division
Department of the Environment

About the report

The open cut El Sherana mine was the biggest producer of uranium in the South Alligator river valley, with 39,000 tonnes of high grade ore mined and processed at the Moline mill.

The mill camp site is located on the road to Coronation Hill. It has a frontage of approximately 50 m, and consists of several houses, storage sheds and plant buildings. The camp site was surveyed by technical staff of the Environmental Research Institute of the Supervising Scientist (eriss), during visits to the area in June and July 1992. These measurements were a part of the eriss contribution to the hazard reduction exercises carried out at a number of abandoned mine sites in Kakadu. The measurements at EI Sherana camp involved gamma dose rate surveys of two contaminated areas of soil, and also of two contaminated concrete blocks, both before and after the hazard reduction work.

Approximately 35 km south-east of the EI Sherana site lies the abandoned Sleisbeck mine. Sleisbeck is located in the Katherine valley, within Stage III of Kakadu National Park, and can be accessed via a 40 km rough track from Coronation Hill through the old Gimbat Pastoral Lease. Although the access road to Sleisbeck is sign posted with regard to the hazard in the area, there is no other obvious indication of a hazard at the site. In 1957, 637 tonnes of medium grade ore was mined and transported to Rum Jungle for treatment. A considerable quantity of low grade ore was also mined, stock piled on the site and later removed.

The old mine workings at Sleisbeck were surveyed for radiological hazard by the technical staff of the Environmental Research Institute of the Supervising Scientist, on the 17 May 1990. The workings consist of an open pit approximately 100 m x 30 m in dimensions, and 3 dump areas. The survey involved external gamma radiation measurements and collection of soil, water and plant samples for radionuclide analysis.

In a letter to Senator Robert Hill, dated 8 May 1997, Mr. M. Sherwood raised concerns about the safety of the EI Sherana and Sleisbeck sites. Subsequently Parks Australia requested " ... assistance and advice regarding the danger the radioactive material (at the EI Sherana camp and Sleisbeck pit) may pose to staff or visitors to those sites ... ". In response to this request a radiological survey in and around the storage sheds at EI Sherana was carried out on 27th May 1997 by technical staff at eriss. Additional surveys of the Sleisbeck overburden dump, pit and pit wall areas were also made on the 28th May 1997. The objective of this report is to provide current data on the radiological hazards present in these areas. This was done with a view to providing Parks Australia and UMARB (then OSS) with some of the information required to make a preliminary risk assessment of the sites.