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Operations at Macraes Mine require fossil fuel use in a way that could soon be seen as unsustainable, a hearings commissioner says.
However, he was unable to take this into consideration under the law when granting consent for the project's expansion.
Independent commissioner Brent Cowie granted a raft of consents for the expansion of the site this month.
However in his decision he noted ''the extraction of relatively small amounts of gold from huge volumes of ore-bearing rock'' used large volumes of fossil fuels.
''Not least in the massive trucks which carry rock to the processing plant and which each use about 300 litres of diesel an hour.''
As the effects of climate change became ''more daunting and challenging'' it was possible the open cast mining of the type carried out by OceanaGold at Macraes would someday no longer be considered sustainable, at least in New Zealand, he said.
''At this time, however, given the low weighting given to consideration of climate change in the [Resource Management Act], this is not a matter that I have given any significant weight to.''
Dr Cowie's comments echo the debate concerning a consent granted last month by the Environmental Protection Authority related to OMV's intention to drill an oil and gas exploration well in the Great South Basin.
Submitters became frustrated at the hearing that they were restricted to the consent at hand and unable to express views on the wider project, including its effects on climate change.
Environment Minister David Parker has said climate change was within the scope of its review of the Resource Management Act, which has jurisdiction up to 12 miles off shore.
However there were no plans to do the same for the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act, which has effect beyond this point.