New Zealand Underground Mine Commissioned


Diagram indicating the layout of the recently commissioned Frasers Underground mine beneath
OceanaGold's Macraes open-pit operation.
OceanaGold Corp. on January 17 reported successful commissioning of the Frasers Underground mine at its Macraes operation on the South Island of New Zealand. This is the second new gold mine that the company has commissioned in the past 12 months, following startup of the Reefton mine; and according to Oceana- Gold, was completed on schedule, at a capital cost net of gold revenue of NZ$33.4 million. The company also plans development of two additional mines in the near future.

Frasers Underground has been developed on the down-dip extension of the orebody currently being mined via the Macraes open-pit. This new underground mine is scheduled to produce approximately 900,000 mt of ore in 2008 which will be processed through the Macraes processing plant. Frasers Underground concentrate represents about 16% of the total throughput for the Macraes autoclave with the remainder coming from Macraes and Reefton concentrates. Underground development to date totals 6.5 km and will continue simultaneously as mining progresses. Exploration is ongoing and the company reports that results at depth continue to demonstrate strong continuity with numerous higher-grade areas defined.

John Kinyon, vice-president of New Zealand Operations commented, “We are pleased to have completed the Frasers Underground within our scheduled timeframe. Development rates exceeded our targets during 2007 and were able to access more ore faces than anticipated. As a result, Frasers has been scheduled to produce 900,000 tons of ore in 2008 versus the 800,000 tons anticipated in the project’s feasibility study. The addition of our third mine in New Zealand gives OceanaGold significant flexibility to achieve its 2008 production targets.”


Three new high-capacity Outotec flotation cells were recently installed at OceanaGold’s
Macraes gold plant in New Zealand.
OceanaGold previously announced in mid-December 2007 that it had successfully commissioned three new Outotec TankCell 300 flotation cells at the Macraes processing facility. Each TankCell 300 has a capacity of more than 300 m3 making it the world’s largest commercially operating flotation cell. The new installation of 300 m3 tanks combined with Macraes existing Outotec 150 m3 tanks replaced the site’s original two trains of column and conventional flotation cell which, according to the company, represents a significant reduction in process plant footprint and is expected to reduce maintenance and operating costs.

OceanaGold said it had achieved an initial increase in bulk flotation recovery of 4%, which exceeded the projected recovery increase of 2.5%. Based on the projected recovery improvement payback was 16 months, but is now expected to occur sooner following final commissioning of the complete circuit. By late December, OceanaGold expected that Macraes would be able to treat 6 million mt/y of ore.

The Macraes processing facility will treat all ore and concentrate produced at the Macraes, Frasers and Reefton mines.

As featured in Womp 08 Vol 1 - www.womp-int.com