New Century Resources' hopes include recovering some of the metals released into the King and Queen rivers during the veteran Queenstown copper mine's earlier decades.

"We need to look at the substantial environmental issues as opportunities as well," New Century managing director Patrick Walta said on Thursday.

"There's a legacy of 80-90 years of tailings being put down the river.

"One reason the water quality is poor is there are a lot of metals in the water."

Mr Walta said the minerals were inherently valuable and New Century would sell them if it could remove them from the water.

That would help offset the water treatment cost.

"We look at rehabilitation as an opportunity for value creation, as opposed to just a cost," he said.

"I can't guarantee water treatment is viable."

According to the state Environment Protection Authority: "The last century of mining at Mount Lyell exposed massive areas of broken sulphide-rich rock to the air and to high levels of rainfall, forming sulphuric acid that leaches out the other metals in the rock, including copper, aluminium, iron, manganese and zinc."

It said the acid and metalliferous drainage would continue to contaminate the river system for centuries unless remedial action was taken.

"The only solution is to treat the AMD from the Mount Lyell site by extracting metals or neutralising the acid," it said.

New Century recently entered a two-year option agreement with Mount Lyell owner Vedanta Resources and will evaluate the potential to resume mining and reprocess tailings.

The mine has been on care and maintenance since 2014.

New Century would take on Vedanta's $6.1 million of rehabilitation liabilities for the period back to 1999 if the sale went ahead following the evaluation process.

The liabilities from the earlier damage would technically stay with the state government.

"While the Tasmanian government does own the pre-1999 legacy, there's opportunity there," Mr Walta said.

State Resources Minister Guy Barnett said the option deal was "a significant step forward in the right direction and, together with the local community and the mining industry, we are very encouraged".

"A working mine is good for the economy and even better for the environment and the community.

"New Century have a very positive track record of projects that deliver benefits for the environment and the economy.

"The morale at the mine has lifted and the feeling in town and on the West Coast is very positive

"There's a lot of positivity in the mining industry at the moment."