OceanaGold has been mining at Macraes flat in East Otago since 1990. Along the journey the company has gone to extra lengths to manage environmental effects and to work with the local community. The Deepdell North pit development is the latest in a string of nature conservation successes.

OceanaGold’s opencast Macraes mine in East Otago is New Zealand’s largest gold mine which has been in operation since 1990.It covers more than 1000 hectares and has produced more than 5 million ounces, providing employment for around 600 full time staff.

The company’s approach to environmental management at all of its sites is to follow the “effects management hierarchy” – a stepwise process of avoiding, remedying (repairing) and then mitigating (making less severe) environmental effects; and, for residual effects, offsets and compensation to enhance biodiversity and wetlands at other sites.

Research is a key component of OceanaGold’s work at Macraes. Toxicology studies on elevated sulphate levels in mine drainages confirmed the instream fauna tolerance to consented discharges of SO₄, an important finding to ensure continued operations. For this work, OceanaGold won a Minerals Sector Award for environmental management in 2019.

This case study focuses on the reopening of the Deepdell pit, which provides a two-year bridge between operations drawing to a close at parts of Macraes, and new operations starting, eg the Golden Point underground mine.

Deepdell presents a challenge in managing surplus rock, as well as for wetland, shrubland and lizard conservation.