Cyanide to be used in proposed processing plant at West Coast goldmine

Sunday, 18 September 2022

Site establishment works under way at the Snowy River Mine near Reefton, which borders the Victoria Forest Park.

A company with an ambitious plan to produce 700,000 ounces of gold from its mine on the West Coast now wants to process the gold onsite using cyanide instead of carting it to Otago.

Federation Mining received a $15 million loan from the Government’s Provincial Growth Fund to progress the Snowy River Mine at Waiuta, near Reefton.

It is now seeking consents from the Buller District Council and the West Coast Regional Council to build a processing plant and a water treatment plant, and to increase the size of its stack of waste rock.

The mine is near two historic gold mines the Government spent $3.6m cleaning up in 2017. Arsenic levels at the mines had been among the highest recorded anywhere in the world.

Almost 5500m of tunnels at the Snowy River gold mine near Reefton on the West Coast are now complete.

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Federation Mining said it was committed to adopting best practises for protecting the environment.

The Snowy River runs through the mine site, which is bordered by the Victoria Forest Park. Forty-seven people are currently employed in its tunnelling operation, and it expects to employ more than 110 staff when the mine moves to full production in 2024.

Federation Mining is in the process of acquiring the mine from OceanaGold, which holds resource consents issued in 2014 for two tunnels of about 8400m in length and to discharge surface water, groundwater, and contaminants to land and indirectly into the Snowy River.

OceanaGold has planted more than 800,000 trees since 2016, in an effort to restore their former gold mining site near Reefton. (file video first published in August 2022)

The processing plant was not included in the original resource consent because OceanaGold intended to transport the ore for processing at its now closed Reefton facility or Macraes in Otago.

The consent application says transporting the ore offsite was no longer the most practicable or efficient option.

The new application to the Buller District Council says the processing structures would be on land where farming and gold dredging had already happened.

“A small portion of the infrastructure will impact on native vegetation (i.e. the regenerating mixed beech forest). This vegetation is not considered to be of conservation significance,” it says.

“While the river is currently in good condition, it cannot be regarded as having particularly high conservation value.”

Environment Canterbury candidate Genevieve Robinson has concerns about the environmental impact on waterways and forest area from a gold mine near a property she owns on the West Coast.

The company expects to extract and process 4 million tonnes of ore and produce 2 million tonnes of waste rock – 50% of which would be returned underground and the rest put into a clay-lined waste rock stack that would eventually be covered over with native plants.

The gold would be extracted from the ore using cyanide, which would be delivered to the plant in 1 tonne bulk bags opened in a dust box and then detoxified in tanks, dried out and discharged to a bunker underground.

The company also wants a new water treatment system at the site to manage leachate from the waste rock stack by directing stormwater and creeks around the mine and constructing treatment ponds to remove other contaminants like arsenic and nitrogen (used in explosives) from the water.

The Snowy River gold mine portal near Reefton on the West Coast

The site would not disturb the beech forest, and would reduce truck movements from 26 to 10 a day, it says.

The application says the Department of Conservation (DOC) was consulted and did not raise any issue with the leftover materials – called tailings – returning underground. Te Rūnanga o Ngāti Waewae supported the development as long as it adhered to consented environmental limits.

The Buller District Council said a decision on whether the application would be publicly notified had not yet been made.

The regional council said the application was being processed with limited notification. It was currently on hold awaiting affected party approvals from Te Rūnanga o Ngāti Waewae and DOC.

Snowy River Rd homeowner Genevieve Robinson, who is running for a spot on regional council Environment Canterbury this year, said she was concerned about the effect the mine would have on the surrounding environment.

“The Victoria Forest Park is virgin beech forest. Considering it’s such a wet environment and this area has a lot of rainfall, I’m concerned about the environmental impact of this mine on the ground water. It feels so wrong,” she said.

Federation vice president Simon Delander said the company’s environmental monitoring programme that was developed with New Zealand experts, scientists and stakeholders, and no water would be released from the treatment ponds unless it met quality criteria.

“The area will be returned to a nature state as agreed with the landowner,” he said.