The Senate Standing Committee on Environment and Communications conducted the inquiry over a period of almost two years, including a public hearing in Burnie and site visits to the Mt Lyell and Savage River mines.

A final report, released last week, found clear issues of "significant environmental and social concern arising from legacy mining sites in Australia" but contained no unanimous recommendations from committee members.

Dr Anita Parbhakar-Fox, adjunct senior researcher with UTAS' Centre for Ore Deposit and Earth Sciences, thought the fact agreements couldn't be reached highlighted the complexity of the issue, with it "almost impossible" to find commonalities - and therefore recommendations - when the states and territories are responsible for governance.

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Dr Parbhakar-Fox said she appreciated the efforts of the committee and noted the 32 recommendations outlined by the Greens provided some "detailed suggestions" worthy of consideration at a federal level.

"The establishment of a National Abandoned Mines Commission may be the best way forward to further define the scale of the problem and reveal the complexity of the issues being faced across both Tasmania and Australia," Dr Parbhakar-Fox said.

"It has been a long time since this issue has been championed and I'm pleased it's been raised because it's a key issue Australia that needs to be dealt with - with over 50,000 abandoned sites to manage."

Nicole Sommer, chief executive of Environmental Defenders Office Tasmania, echoed the view of the committee's chairwoman - Victorian Greens Senator Janet Rice - on the lack of a clear path forward.

Ms Sommer said the most pressing need was for increased transparency around the financial reporting of rehabilitation facilities and "consistent and enforceable conditions" on Commonwealth mine approvals to reduce the risk of creating new legacy issues.

"While mining projects are principally regulated by states, there are a number of actions that could be taken at the commonwealth level," she added.

In its submission to the inquiry, the Tasmanian government - and a number of others - also argued for clearer financial reporting, suggesting the Commonwealth could do so with reforms under the Corporations Act.

Scott Jordan, takayna/Tarkine campaigner with the Bob Brown Foundation, said the report highlighted "major failings" among mine rehabilitation practices and polices, including the Tasmanian government.

"Having been presented with this overwhelming body of evidence of systemic failures, it is farcical that the Government Senator's report adopts a 'nothing to see here - not our problem' approach, reminiscent of the attitude that led us to the problem in the first place," Mr Jordan said.

"Equally damning is Labor's failure to support any of the Committee Chair's 32 recommendations."

Among an abandoned mines commission, the Greens recommendations included research into ecosystem restoration and treatment options for waste materials, enforceable targets, amendments to federal environment regulation and closer engagement with native title holders.

In the government senators' comments, Tasmanian Liberal Senator Jonathon Duniam - deputy chairman of the committee - wrote that national policy in the area should be developed at a COAG level and any proposal placing additional or retrospective obligations on sites could jeopardise the operation of Australia's resources sector.

Labor senators recommended rehabilitation-related conditions for mining projects under the EPBC Act be included in consultation as part of an upcoming review of the act.

Tasmania has had an abandoned mines program in place since 1996, which works to rehabilitate sites by removing risks to health and safety through stabilisation, erosion reduction, maintaining or increasing biodiversity and improving contamination.

A portion of mining company royalties in the state are paid into a trust fund for the program. Since its inception, 60 sites have received rehabilitation work, the committee heard.

Witnesses giving evidence at a public hearing in Burnie commended the work being undertaken at Savage River mine in the state's North-West, as an example of a site where secondary mining operations were assisting with the environmental legacies.

['Disappointing': Mine rehabilitation inquiry split on path forward]

In response to questions Saturday, a Tasmanian government spokesperson said it was a requirement that land disturbed by works under an exploration licence or mining lease be rehabilitated to the satisfaction of the Director of Mines.

"All major mine site security deposits are reviewed approximately every three years, usually coinciding with the requirement to update the site closure plan," the spokesperson added.

"In most cases, where possible, rehabilitation is expected to be carried out progressively over the life of the licence or lease, and must be completed as far as practicable before the tenement expires."

"The Hodgman Government made amendments to the Mineral Resources Development Act 1995, which came into effect in November 2017, including changes to allow for greater flexibility in varying security deposits, to incentivise progressive rehabilitation."

"Mineral Resources Tasmania holds about $59 million in security deposits, and only accepts security deposits in the form of cash or unconditional bank guarantees. Term deposits are no longer accepted and are being phased out."

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