Liberty Bell Bay has been ordered to stop removing by-products from its northern Tasmanian smelter after environmental regulators raised concerns about “significant land use and development issues”.
Manganese ore smelters produce silica-manganese slag (a dense, glassy substance) as a by-product.
From October 2021, smelters will be allowed to approve the use of slag in projects outside their industrial zones.
This material can be used in place of rock or gravel to form a hard surface area, as an aggregate to bond to concrete or asphalt, or as a road base.
Liberty Bell Bay is Australia’s only manganese alloy smelter. (ABC News: Owain Steer-James)
However, the plan was halted in September 2024 after documents released under the Right to Information (RTI) Act revealed that the Environmental Protection Agency (EPA) was concerned that the slag “may not be reused in a way that adequately reduces environmental risks.”
The ban on the reuse of slag outside industrial zones remains in place, and smelters are to brainstorm uses for the slag they still have on site.
Liberty Bell Bay said the slag is stored and managed in a way that “does not pose a risk to people or the environment.”
“Liberty Bell Bay actively operates its smelter to comply with EPA requirements and there have been no violations of LBB’s slag recycling process,” the company’s statement said.
Concerns raised by local councils
The EPA’s intervention followed concerns from Georgetown Council that the slag was not being recycled according to an approved plan.
“For example, a large amount [silica manganese] “The slag is deposited at a development site off Georgetown’s main road, used as a general landfill along with other waste, and has no cap,” the EPA said in a letter to Liberty Bell Bay general manager Paul Venter.
“While the council has given other examples (e.g. private roads), [silica manganese] The slag is spread as finished road material and remains uncapped. ”
Officials have since identified 16 locations where slag was recycled, including eight residential sites.
“One of the large sites outside the Bell Bay Heavy Industrial Area has been investigated and an environmental notice has now been issued,” it said in a statement provided with the RTI document.
“There are a number of smaller sites outside the Bell Bay Heavy Industrial District where slag is being recycled.
”The environmental risks associated with these sites are considered to be low and will be informed by relevant information from ongoing research into slag.”
An environmental protection notice was issued to G & M Viney Super Co Pty Ltd in May 2025, requiring the owner to apply for relevant approvals and take steps to reduce risks, including restricting access, implementing dust prevention measures and collecting and treating rainwater.
The property owner has been contacted for comment.
A Liberty Bell Bay spokesperson said the slag was used in an approved manner, but the property owner did not follow George Town Council guidelines.
Georgetown Mayor Greg Keyser said the council was concerned about ensuring slag reuse within EPA requirements and establishing accountability for this.
Slag is a byproduct of manganese production.
(ABC News: Maren Preuss)
EPA concerned about potential spill
In September 2024, the EPA told Liberty Bell Bay General Manager Paul Venter that it believed the use of slag outside industrial zones “could pose significant land use and development issues.”
Officials told the ABC these concerns include the potential for runoff or leachate from uncapped slag, as well as changes in topography that could alter the flow of stormwater and increase the risk of land flooding.
Jia Huan Liew, a lecturer in freshwater animal ecology at the University of Tasmania, said trace amounts of heavy metals could be carried into streams and rivers when water passes through materials like slag.
“The materials you use to build things are important because unless you have something fairly safe like gravel, you run the risk of leachate carrying things that are of environmental and health concern.”
Dr. Liu said.
Manganese ore from the Liberty Bell Bay smelter. (ABC News: Maren Preuss)
The RTI document does not identify potential health impacts, only land use and development concerns.
Dr. Liu said it makes sense to ban slag reuse until the EPA further monitors potential problems.
“Generally, my advice is to err on the side of caution,” he says.
”I think the EPA has its own standards and regulations to follow, but I generally think that if there’s a risk, it’s safer to at least stop what’s happening. [and] Conduct research.”
Liberty Bell Bay said it is “actively operating its refinery to comply with EPA requirements.” (Provided by: Liberty Steel Group)
Usage options under consideration
Smelters are beginning to consider other options for reuse.
In an October 2024 email, an anonymous Liberty Bell Bay employee listed several options under consideration, including use as fill material in large-scale projects such as the upcoming stadium and Burnie Port in Hobart.
It was also being considered whether the slag could be granulated to form “extended lightweight products” for use in cement, coastal restoration, render and mortar.
A company spokesperson did not confirm whether any of these options have been advanced, but noted that silica-manganese slags are used in a variety of options around the world.
Georgetown Council hopes this material will be used to support the circular economy.
“The council wants to see that materials are used in an environmentally responsible way that supports a circular economy, that guidelines for reuse are clear and that systems are in place to ensure they are used in accordance with the guidelines,” Mr Keyser said.