Commissioner warns proposed Santana gold mine should be declined if major environmental risks can’t be avoided
Tuesday, 14 April 2026
The Parliamentary Commissioner for the Environment has issued strong warnings over a controversial gold mine proposed for Central Otago.
Simon Upton has told the fast-track panel considering Santana Minerals’ application for a large gold mine near Cromwell, in the hills above the Clutha River in Central Otago, that the “project comes with considerable environmental risk”.
Upton also pointed to what is at stake if the mine is given the go-ahead, saying the panel has “a heavy responsibility”.
“Importantly, the panel has one opportunity to get this right.”
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Australian company Santana says its Bendigo-Ophir mine is the most significant gold discovery in New Zealand for 40 years, and proposes to build four open pits, the largest of which would be 1km long and 300m deep, as well as mining underground.
The pits would not be filled in after mining is completed, and a 2km long tailings storage dam containing chemical waste slurry would also remain forever.
The project has divided opinion within Central Otago and nationally, with strong concerns being raised over the mine’s environmental and economic effects.
The fast-track panel has until October 29 to decide if the mine is approved or not.
The Parliamentary Commissioner for the Environment is one of a number of interested and affected parties the fast-track panel has sought input from.
Upton pointed to the lack of experience or expertise within New Zealand to assess the risks associated with such a mine, and called on the panel to get advice from independent experts to gauge the mine’s risks, likely from overseas, where there were well-developed regulatory systems.
“In my view, the panel needs to assure itself, with the assistance of independent verification, that what is proposed can mitigate the risks as far as reasonably practical for at least a century after [the mine’s] closure.
“If the panel cannot receive that assurance within the timeframes of the fast-track approvals process, the Bendigo-Ophir Gold Project application should be declined.”
As part of his submission, Upton commissioned research into international mining risks, including acid mine drainage and tailings failures.
He pointed out Santana’s project raised a range of potential environmental issues, but confined his initial comments to water quality and the risks to it posed by the mine.
“What is being proposed involves the storage - in perpetuity - of large quantities of potentially hazardous mining residues in the headwaters of one of New Zealand’s largest river systems - an area that is also susceptible to very large earthquakes.
“Assuming everything goes to plan, and key risks do not eventuate, it seems reasonable to think that the economic benefits of the Bendigo-Ophir gold mine will exceed the environmental costs.
“It is what happens if things do not go to plan that is my concern.”
Upton stressed much more clarity was needed about the level of risk that was acceptable for the mine, and what conditions could be imposed to reduce that risk.
“Where conditions are insufficient to address the reasons for them being set, and adverse impacts will prevail, the panel should decline the approvals sought.”
He raised the prospect of seepage into the groundwater from the tailings facility holding mining residue, and uncertain assurances from Santana’s own experts whether this could be prevented entirely.
“The applicant (Santana) is already proposing a number of mitigations. The question is whether more could be done.
“It is important to note that polluting and potentially toxic leachate from tailings facilities can continue for decades and even centuries after mine closure.
“It is critical, therefore, that long-term risks are assessed and a plan implemented to manage them.”
Upton also raised the issue of who was responsible if something did go badly wrong at the mine.
While an environmental bond had been proposed by Santana, Upton said it wasn’t clear if this would cover catastrophic environmental damage, who would be responsible for ongoing monitoring, what water quality limits would be used, and when Santana’s obligations would expire, given environmental risk from its mine could continue for decades after it was closed.
Upton also pointed to imprecise wording in Santana’s application, which provided little clarity regarding such issues.
“Consider the objective that ‘contamination caused by the operation is appropriately remediated or managed’, for example. What ‘appropriately’ means in this context is anyone’s guess.”
And he warned against negotiating or changing environmental goals or standards after the mine had been given the green light, stressing one of the panel’s tasks was to decide on appropriate limits and conditions, well beyond the mine’s life.
Upton said some overseas jurisdictions required mines to be completely non-polluting, and that water quality should remain the same as before mining began.
Upton closed his submission by emphasising that “the risks of acid mine drainage and tailings failures are present in New Zealand and, given our seismic risk, are arguably greater than elsewhere.
“There are both ongoing risks of gradual pollution, as well as the risks of catastrophic failure if tailings facilities fail.”
Santana Minerals was approached for comment.