Environment Minister Sussan Ley met environmentalist leader Bob Brown at the Tarkine Wilderness Lodge at Meunna on the second day of her fact finding mission to help her make a call on mining company MMG's controversial proposed tailings storage facility west of Rosebery.

Ms Ley, who visited the tailings storage proposal area with company representatives on Wednesday, will decide if the proposal needs further assessment under the Environment Protection and Biodiversity Conservation Act.

A decision is expected by July 23.

On Wednesday, before her site visit, Ms Ley said she had an "absolutely" open mind.

Former Australian Greens leader Dr Brown said: "There are alternatives for MMG's dump, but not for the rainforest's wildlife."

Environmentalists' long-running protests against the tailings storage proposal continued on Thursday.

The Bob Brown Foundation said a new group of its "Tarkine defenders" had closed down MMG's roadworks to its "proposed toxic waste dump in the southern part of the same forests".

Eighteen-year-old artist Billie Rafferty, who locked herself to an excavator, said: "Sacred takayna is not the only option for this tailings dam."

"How dare MMG irreversibly scar 285 hectares of pristine rainforest?"

MMG will need a new tailings storage in the next few years if the Rosebery Mine and its estimated 500 jobs are to survive.

The company has confirmed it has other potential tailings dam sites.

Braddon Liberal MHR Gavin Pearce - who wants the proposed tailings dam built - said the proposed area had been logged many times, had had fires though it and was part of MMG's mining lease.

"I can't thank the Minister enough for taking the time out to visit Tasmania, to walk the ground and to listen, not just to MMG, but she's also listening to the Bob Brown Foundation," Mr Pearce said..

"She's being fair and transparent; I'm pleased about that."

He said he and Ms Ley were impressed by the depth of detail MMG representatives provided.