Rosebery Mine owner MMG Limited and the environmentalist Bob Brown Foundation have taken further swipes at each other as tensions build over a controversial tailings storage proposal.
MMG says the mine will have to close by 2023 if a new tailings storage facility is not developed.
The foundation - which opposes MMG's preferred South Marionoak site - also confirmed during the week it would oppose the alternative Natone Creek site, which the company said was yet to be proven as a viable and safe location for tailings storage.
The Bob Brown Foundation - which organised a long run of protests at South Marionoak before MMG paused preparatory work - has continued to say MMG should explore alternatives.
One suggestion was building a paste fill plant and pumping dewatered tailings back underground to fill voids left by mining.
Above all, they are not safe.MMG
"The alternatives that have been put forward by the Bob Brown Foundation are not informed by science, engineering or knowledge of the Rosebery site and the mine operation," MMG said.
"Above all, they are not safe.
"The option of a paste fill facility at the Rosebery Mine has been thoroughly explored over many years and ruled out due to a combination of environmental, geological, operational and extreme safety constraints.
"The 85-year-old underground mine is not designed to cope with paste fill and doing so would destabilise mine workings and place our workforce at direct risk of harm.
"Decisions about the future of the Rosebery Mine and its 500 employees should be guided by facts, science, and engineering, not by those making uninformed suggestions who have no technical expertise or experience in the management of safe tailings storage."
The foundation hit back at MMG's paste fill comments.
"They would say that, wouldn't they?" it said.
Foundation campaigner Jenny Weber said: "MMG's refusal to build a paste fill plant highlights the need for an independent assessment, including into worker safety, for all the options and the company's failure to have future-proofed their mine."
"Paste fill is accepted mining best practice, taking into account worker safety.
"That is why it is the option of choice for tailings disposal overseas and elsewhere in Australia, as MMG has now acknowledged.
"We call on MMG to release all its reports, unredacted, into the paste fill option as well as all alternative options.
"We also call on MMG to open its facilities at Rosebery to independent assessment."
The BBF said it would hold an open day on Sunday "into the rainforests threatened by MMG's proposed toxic metals waste dump".