The original Radium Hill project included the establishment, operation and decommissioning of the Radium Hill underground uranium mine and the Port Pirie uranium treatment plant. This project was commissioned and operated by the South Australian Government to satisfy a contract signed by the Commonwealth and State government with the UK–USA Combined Development Agency for delivery of uranium over a seven-year period.
Establishing the plant
Investigations into selecting a suitable site for the treatment of the Radium Hill ore commenced in 1952. Construction of the Port Pirie uranium treatment plant was completed in August 1955.
The chemical treatment plant at Port Pirie consisted of three parts:
- Leaching of uranium concentrate to dissolve the uranium-bearing mineral. This process was a batch process, with 98% sulfuric acid used in the digesters
- Separation of the liquid carrying the uranium from spent ore after leaching (counter current decantation plant). In this process, the uranium-rich liquid was separated from the solids by passing through thickeners. The washed, spent ore was mixed with waste liquid from the plant and pumped to the tailings dams
- Recovery of the uranium by precipitation of the uranium salt. This material was dried using a hot blast type unit. The outgoing air passed through an electrostatic precipitation unit to remove uranium dust before discharging to the atmosphere
Port Pirie uranium treatment plant
Analytical laboratory, Port Pirie uranium treatment plant
Drum filter, Port Pirie uranium treatment plant
Following decommissioning of the Port Pirie treatment plant site in 1962, attempts were made to establish alternative uses including the pursuit of rare earth elements. In the subsequent years ongoing maintenance of the site has included covering much of the tailing dams with granulated slag from the neighbouring lead smelters; this has proved very effective in the minimisation of gamma radiation, radon emission and dust suppression.
The site is a registered premise under the Radiation Protection and Control Act 1982 (RPC Act). A certificate of registration issued for the site by the Environment Protection Authority includes a number of conditions to ensure the development of an appropriate overall long-term management plan.
The overall management of the site is being undertaken in a series of phases:
- Phase 1 (which was effectively completed in 2004) was a preliminary investigation of the site
- Phase 2 (the current phase) is directed to a more detailed site characterisation
- Phase 3 will cover risk assessment and control selection for the site. Upon completion of the 3rd phase sufficient information should then be available to enable an effective and informed decision to be made on the future management of the site
- Phase 4 (the final phase) will see the development and implementation of an appropriate long-term management plan for the site
Recently completed projects (supporting the current phase) have included:
- Site contamination surveys
- waste quantification and site survey
- Resource economic studies
Demolition of former laboratory on the Port Pirie treatment
plant site (2006)