The mining and exploration quest in and around New Zealand’s Waihi gold mine involves a high degree of social licence.

A consultant to OceanaGold Corporation (TSX & ASX: OGC) working on the Waihi operations, Rick Streiff, told attendees at the recent Gold17@Rotorua Conference that in Waihi the Martha open cut mine has operated in the town and that the latest underground operations go underneath some housing.

Streiff, who also undertook work for previous owner Newmont Mining, said it was clear from the outset that the mining companies needed to listen to the concerns of Waihi townsfolk and he believes this has been a successful operation.

There were some challenges for exploration including when operating teams needed to undertake CSAMT work to enhance underground targets that the wiring near houses did not create any problems. This took in looking out for dogs and cats.

There were noise issues that needed to be covered, including encasing drill rigs in containers to mute the noise and to ensure at night functions such as not using hammers on drill steels or rods.

Modern gold mining at Waihi began in late 1980s with a pit at Martha over the original underground mines and this was originally operated by a joint venture of US and Australian companies, then taken over by Normandy Mining before that big Australian company was taken over by Newmont, which in turn sold Waihi to OceanaGold in 2016.

Rick Streiff said that following on Martha’s develop the underground discoveries to follow included Moonlight-Favona, Trio and the 2009 discovery of Correnso, now the current mining focus.

Discovery of Correnso came about when exploration near the Reptile Vein came across an intersection that appeared to be “something else.” Ongoing exploration outlined Correnso as a significant target and there was excitement with an intercept of 11.5 metres grading 17 grams/tonne gold.

Broader regional exploration advanced originally by Newmont which undertook a remapping programme in 2008-09 identified a host of targets including the large WKP deposit which had seen holes like WKP24 outlining a wide zone grading 1.5 g/t and, later WKP35 which outlined an equally wide zone and a related narrow vein high-grade zone.

Streiff said modern mining at Waihi has seen about 2 million ounces of gold produced at Martha and roughly about one million ounces coming from underground mines. The ratio of silver varies, with Martha having had 10:1 silver to gold and Favona 1:1.

Ross Louthean
22 Feb 2017
This article was originally published in NZResources magazine and is reproduced here with the publisher’s permission which is gratefully acknowledged.