EPA Halts Slag Reuse at Liberty Bell Bay Smelter Amid Environmental Concerns
Liberty Bell Bay, a manganese ore smelter in northern Tasmania, has been instructed by the Environment Protection Authority (EPA) to cease the removal of its silica manganese slag by-product from its industrial zone. The directive, issued in September 2024, followed significant concerns from the regulator.
The EPA cited "significant land use and development issues" and potential environmental risks associated with the slag's reuse as the basis for its ban.
Since October 2021, the smelter had received approval to utilize the slag in various applications, including as a substitute for rock or gravel in hard-surfaced areas, as aggregate in concrete or bitumen, or as road sub-base material.
Regulatory Intervention and Company Response
Documents released under Right to Information laws revealed the EPA's central concern: the slag "may not be being reused in a way that adequately mitigates environmental risk." The ban remains in effect, compelling Liberty Bell Bay to explore alternative uses for its existing stockpiles.
Liberty Bell Bay has asserted that its slag is stored and managed in a manner that ensures it "poses no risk to people or the environment." The company also stated its proactive compliance with EPA requirements, emphasizing that no breach in the slag reuse process has occurred.
Council's Concerns Prompt EPA Action
The EPA's intervention was directly prompted by concerns raised by George Town Council. The council indicated that the slag was not being reused in adherence to the approved plan. Examples cited by the EPA included a substantial quantity of slag used as general fill at a development site, left uncapped alongside other waste. There were also instances where slag was spread as uncapped finished roading material for driveways.
The EPA identified 16 sites where the slag had been reused, including eight residential locations. An Environmental Protection Notice was issued to G & M Viney Super Co Pty Ltd in May 2025 for one large site situated outside the industrial precinct. This notice mandates the application for relevant approvals and the implementation of risk mitigation measures such as restricting access, controlling dust, and managing stormwater. For smaller sites outside the precinct, the EPA currently considers the environmental risk to be low, pending further investigation.
Environmental Risks Identified
The EPA informed Liberty Bell Bay in September 2024 that slag use outside the industrial zone could lead to significant land use and development issues. Key concerns include the potential for runoff or leachate from uncapped slag, as well as alterations to landform that could impact stormwater flows and increase inundation risk.
Jia Huan Liew, a lecturer in freshwater animal ecology at the University of Tasmania, commented on the potential hazards. He noted that water passing through materials like slag could transport traces of heavy metals into water bodies.
Jia Huan Liew recommended caution and temporary halts until potential issues are thoroughly studied.
Future Options for Slag Reuse
Liberty Bell Bay is actively exploring new options for the slag's reuse. Internal communications from October 2024 mentioned potential use as fill in large projects such as the Hobart stadium or Burnie Port. The granulation of the slag to create an expanded lightweight product for use in cement, coastal rehabilitation, render, or mortar is also under consideration.
A company spokesperson did not confirm the progression of these specific options but highlighted global applications for silica manganese slag. George Town Council expressed a desire for the material to be used responsibly within a circular economy framework, with clear guidelines and accountability.