An environmental group has lost its Federal Court bid to halt preliminary works for a controversial mine tailings dam inside the takayna/Tarkine rainforest in Tasmania's west.
The Bob Brown Foundation argued mining company MMG's work would cause "irreversible damage" to the habitat of the rare Tasmanian masked owl.
But the move was dismissed by Justice Mark Moshinsky, telling the court an injunction restricting the company from undertaking the proposed action altogether "appears to go too far".
In January, the federal Environment Department found design and assessment work from MMG did not require approval under the Commonwealth's Environmental Protection and Biodiversity Conservation Act (EPBC).
Despite that, the company had to include measures to protect various species, including wedge-tailed eagles and Tasmanian devils, but not the masked owl.
Justice Moshinsky told the court it was unnecessary to impose an injunction because MMG had now given an undertaking to protect the masked owl.
"Had MMG not offered to give the undertaking, I would have considered it appropriate to make an order restraining MMG," he said.
'Back to the barricades' for conservationists
MMG has agreed to apply a 15-metre exclusion zone to trees suitable for masked owl nesting, with the trees to be marked with tape and their GPS coordinates recorded.
The foundation's campaign manager, Jenny Weber, said it was "not a good day" for threatened species in Tasmania.
"It's a pro-mining decision over the environment," she said.
"Compromising any part of nature is just not acceptable. It's so important to us to keep places like takayna/Tarkine intact."
However, Ms Weber said the court decision had put the Chinese-owned company on notice.
"Every time MMG enters into these forests, it is a step towards building this enormous tailings waste dump."
She said it was "back to the barricades" for conservationists who would continue protesting.
The foundation's bid to overturn federal government approval for the tailings dam will be heard in July.
Tasmania's Rosebery mine, which has been operating since the 1930s, produces zinc, copper, and lead concentrates, as well as gold ore.
The mine has two existing tailings dams, but a new one is required for the mine to survive past 2024.
South Marionoak, across the Pieman River from the Rosebery mine, is where MMG has proposed to build the dam, with a footprint of 285 hectares.
In a statement, MMG general manager Steve Scott said he welcomed the decision.
"It confirms that MMG has, at all times, acted legally under the strict terms and conditions set by the federal government," he said.
"We are taking specific and conservative steps to avoid impacts on masked owl habitat, including applying an exclusion zone around any potential habitat trees."