Client name: Department of Natural Resources and Mines (DNRM), Queensland Government

Location: Near Mt Isa, Queensland

Situation

The Mary Kathleen Uranium Mine was closed 30 years ago and is now owned by the Queensland Government. The site contains valuable rare earth elements within the tailings dam and also holds a potential source of uranium.

As part of the mine closure plan, the tailings dam was covered with layers of rock and soil to contain radon gas, minimise radiation and to minimise water seepage. The waste rock dumps were covered and vegetation established.

The mine is well-known for legacy environmental issues relating to water seepage from the tailings dam.

Uranium mining was banned in Queensland in 1989, with the Mary Kathleen Uranium Mine the last to produce uranium in the State. The ban was lifted in 2012.

In 2013, the Department of Natural Resources and Mines (DNRM) developed an ‘Action Plan to Recommence Uranium Mining in Queensland’, which detailed steps the Government took to ensure a best-practice framework was in place. This included the need for an assessment of the former Mary Kathleen Uranium Mine for re-mining.

DNRM commissioned Coffey to conduct an assessment of the existing environmental risks at the former Mary Kathleen Uranium Mine, so that these can be provided to prospective miners. We were also tasked with the development of an environmental approvals strategy for potential future mining activities.

Solution

We successfully undertook an environmental assessment of the site, which involved developing a comprehensive understanding of the site history and conducting a discrete and focussed mine site sampling program (which included sampling for gamma radiation emissions, water, sediment and asbestos).

The results highlighted potential areas of risk to the environment and the public. Following this, a preliminary risk assessment workshop between Coffey and the DNRM was held, where these risks were discussed. The key environmental risks identified related to radiological hazards and contaminants on the site. Findings of the environmental risk assessment were captured in a report. DNRM has made the report available to future tenderers that may wish to develop the site, so existing hazards and contaminants can be considered, and management options prepared.

Result

The site visit, sampling program, detailed environmental approvals strategy for re-opening the site and the related report, was prepared within a two-month time frame and within budget.

Our environmental condition and rehabilitation assessment report supported the DNRM competitive tender release of the former Mary Kathleen Uranium Mine site to the mining industry. This tender process enables exploration and future mining at the site and supports the Government’s initiative to develop a best practice uranium mining framework for regulatory efficiency and investment certainty, thereby creating new jobs and economic opportunities for the State.