Macraes Open Pit

The Macraes Goldfield is New Zealand's largest gold producing operation consisting of the Macraes Open Pit and Frasers Underground mines. The Macraes Mine has been in operation since 1990 and has produced over 4 million ounces of gold during this time.

Quick Facts: Macraes Open Pit

  • Nominal Production: 90 - 120 koz gold
  • Mine Type: Open pit
  • Measured and Indicated Resources: 3.15 Moz gold 
  • Inferred Resources: 1.5 Moz gold
  • Reserves: 1.23 Moz gold 
  • Estimated Mine Life: end of 2017

Exploration


OceanaGold operates New Zealand’s largest gold mine, Macraes, located 100 kilometres by road, north of Dunedin in the Otago region of the South Island of New Zealand. The Macraes Gold Project comprises two mines; Macraes Open Pit – which has been operating since 1990 and Frasers Underground which was commissioned in January 2008.

The wholly-owned Macraes Mine consists of the Macraes Open Pit which has been operating since 1990 and the Frasers Underground which was commissioned in January 2008, as well as an adjacent processing plant including a pressure oxidation plant for the processing of sulphide ore (which is one of only three in the southern hemisphere).

The Frasers Underground mine was developed to target the extensions of the Macraes ore body and commissioned in 2008. Further information is available on the Frasers Underground page.

The combined open pit and underground proven and probable mineral reserves currently support an approximate eight year mine life at the Macraes Project. Amongst other initiatives, further exploration drilling targeting the deeper extensions of the Macraes ore body is ongoing with the objective of identifying and developing additional underground mines along the strike of mineralisation.  Additionally, exploration is also targeted at other potential surface mineable targets along the Macraes line of strike.

Macraes Processing Plant 

The processing plant is situated within short distance of the Macraes Open Pit and includes a pressure oxidation plant for the processing of sulphide ore (which is one of only three in the southern hemisphere). At the Macraes processing plant, the ore is put through crushing, grinding flotation, fine grinding, pressure oxidation carbon in leach, elution, elctro winning and smelting. Refractory ore requires multistage processing to increase recoveries.

Refractory concentrate from the Reefton processing plant is transported by road and rail to Macraes for treatment through the autoclave pressure oxidation and carbon in cyanide leaching.

Refer to the Reefton page for more details on the Reefton processing plant 

Operating Statistics (Macraes Open Pit and Frasers Underground mines)

Macraes Goldfield

2013

2012

2011

2010

2009

Gold produced (ounces)

198,820

 169,609

174,851

182,759

213,049

Total Ore Mined (tonnes)

6,962,730

 5,558,056

6,589,904

6,365,855

 4,833,671

Ore Mined grade (grams/tonne)

1.27

 1.29

1.07

1.26

1.67

Total Waste Mined (tonnes)  incl pre-strip

38,725,444

36,263,043

44,407,352

43,944,947

 48,578,180

Mill Feed (dry milled tonnes)

5,811,868

 5,789,255

5,817,001

5,458,607

5,635,537

Mill Feed Grade (grams/tonne)

1.30

 1.12

1.12

1.28

1.47

Recovery

81.4%
81.1%

83.3%

81.3%

79.6%

 

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