Santana Minerals asked if it will cover cost of catastrophic failure at proposed Otago mine

The fast-track panel assessing plans for a vast gold mine in Central Otago wants to know if the applicant would foot the bill following a catastrophic failure, and how it plans to protect more than 100,000 at-risk lizards.

The panel has also asked for a social impact assessment and a worst-case economic scenario from Australian company Santana Minerals, which voluntarily paused the processing of its application on Thursday.

The 30-point request for information, issued by the Environmental Protection Authority (EPA) on behalf of the panel, follows months of hearings and expert conferences.

Santana Minerals submitted a 9400-page application in November to build a 1000m by 850m open pit, three smaller satellite pits and a tailings dam in the Dunstan Mountains near Cromwell, where it earlier announced the discovery of a $4.4 billion gold deposit.

The EPA said the application did not adequately address the cultural impacts of the proposed mine and it was unusual the company had not included a social impact assessment.

The authority also asked for evidence as to how the mine would affect water quality and aquatic ecology, along with an assessment of the risk of toxic effects to wildlife and humans arising from poor water quality.

Eight of the requests were for economic calculations, including best and worst-case scenarios for the mine's net present value and tax and royalty payments.

The EPA also asked if Santana Minerals intended to indemnify the public against the costs of "long-term low-risk high-consequence outcomes".

The panel had heard evidence that it could cost "tens of millions of dollars" to relocate 102,000 lizards from the mine but also that the long-term survival rates of relocated lizards were likely to be very low, the EPA said.

"Please advise what consideration has been given to other alternative approaches," the EPA wrote.

In a statement, Santana Minerals chief executive Damian Spring said the panel's request for more information was a clear roadmap for work still to be done.

He said the company welcomed the opportunity to strengthen what was already a comprehensive application.

"We've spent years building the evidence base for this project and this next phase is about making sure the panel has every piece of information it needs to reach a well-informed decision," Spring said.

Timeline unconfirmed

A minute published on the Fast-track website showed Santana Minerals expected the pause would likely last about 20 working days although it later told shareholders the timeline could change.

The company said it had directed the expert panel, its advisers and the EPA to keep working on the application.

Spring said Santana Minerals would also continue working with the panel, regulators, mana whenua and technical experts throughout the pause.

"The statutory timetable may be paused, but the work certainly isn't," he said.

A final decision on the mine was originally expected in October, with a draft decision about six weeks earlier.

Opponents criticise missing information

Santana Minerals has previously said the project would employ hundreds of people and be worth $6 billion in revenue and more than $1b in taxes and royalties for New Zealand.

Opponents of the mine have long argued it could cause harm to the landscape and existing industries.

Central Otago Environmental Society co-chairperson Phil Murray said the panel's request for more information showed the sheer magnitude of the risks it was weighing up.

"The problem with tailing mines internationally is that it's not identified problems that are the underlying cause of tailings dam failure. It is things they haven't identified. The engineers are very smart at solving problems that they can identify. What has been the cause of dam failure in the past are things that they haven't identified. It's quite understandable that the panel will need quite a bit of detail to be reassured that all these matters are covered off," he said.

Murray said he was reassured to see the panel being conscientious in its assessment but the mine should never have been part of the fast-track process.

"I do have confidence in that level of our governance, in the environmental lawyers and the expert panels that we have at that level...but the underlying legislative structure that puts them in this position is totally inappropriate," he said.

"We just hope that this...leads to a decision of Santana Minerals withdrawing the application altogether and waking up to the fact that the community just doesn't see sufficient benefit in it."

The voluntary pause follows a series of hearings in Wellington where the seven-person panel heard from expert witnesses in landscape, heritage, ecology, water, geotech, economics and planning.

Earlier, during three days of hearings in Dunedin and Cromwell, the panel heard concerns from residents and mana whenua.

Sustainable Tarras, another group opposed to the mine, said it felt there had been too many gaps in Santana Mineral's application.

A spokesperson said the latest request for information added to a long list of asks from the panel.

"For the panel to have to ask Santana for baseline information this late in the process underscores the incomplete nature of Santana's original application," they said.