Gold » Macraes 25th
A long history of gold production Jo Bailey More than 4.4 million ounces of gold have been produced at OceanaGold’s Macraes Mine since it opened in 1990, with billions of dollars poured into the Otago economy over the last 25 years. However mining at the site goes back well over 150 years, with some alluvial mining recorded as early as 1862, when prospector James Crombie and his mates were the first to discover gold at Deepdell Creek in the Macraes area. Their discoveries resulted in the establishment of a canvas town 3 kilometres south of Deepdell, which was first known as Murphy’s Flat. In 1865 the town name was changed to Macrae’s Flat. By 1863 around 300 men populated the town, which had four hotels, including Donaldson’s Universal Dining Room, later rebuilt as Stanley’s Hotel, still in use today. The Highlay Reef was discovered in 1888, which a year later was traced to the Golden Point/ Round Hill reef system. On December 24, 1889, the Golden Point Quartz Mining Company was incorporated, and began underground mining operations – almost exactly a century before the Macraes Mining Company began development of today’s mine. Between 1890 and 1930 around 15,000 ounces of gold and 100 tons of scheelite were recovered from ore at the Golden Point, Deepdell, Maritana and Round Hill mines. Many mining areas ceased operations due to the Second World War, with only intermittent mining in the area until the 1950s. The mines remained dormant from then until the 1980s when exploration by various companies was undertaken. In October 1989 Macraes Mining Company Ltd was incorporated, its mining license granted, and in January 1990 the company was listed on the New Zealand and Australian stock exchanges. Development and construction activities at Round Hill got underway in February 1990, with production starting 10 months later. In 1994 an aggressive exploration programme
The Macraes processing plant in East Otago is capable of treating up to six million tonnes of ore per annum.
identified resources at Innes-Mills and Frasers. In November 1995, the project achieved a significant milestone of 500,000 ounces of gold poured since start up. Macraes Mining Company became a wholly owned subsidiary of Gold and Resource Developments NL, with its name changing to Gold
Site aerial maps show the development of the Macraes gold project in recent years.
12 Mining NZ » Autumn 2016
and Resource Developments (NZ) Ltd in 1998, and later GRD Macraes in June 2000. Gold recovery was significantly increased in 1999 through the construction of an autoclave and introduction of a pressure oxidation process. The first millionth ounce of gold was poured at the mine in January 2000.
In 2004, OceanaGold (New Zealand) Ltd was incorporated and became the owner of the Macraes operation, listing on the New Zealand and Australian stock exchanges. A year later Macraes poured its two millionth ounce of gold. Frasers Underground mine was commissioned in January 2008. On December 1, 2010 the Macraes operation celebrated a prosperous 20 years of mining life with an Open Day that was attended by 2,500 visitors. By March 2014, the operation’s four millionth gold ounce was poured. The actual open pit mining process has remained relatively unchanged during the last 20 years, with open pit benches of 7.5 metres drilled and mined in 2.5 metre flitches. Around 3.5 million tonnes of ore are produced at the open pit Macraes mine utilising conventional excavator, truck load and haul, with drill and blast activities an important part of the process. The Frasers underground mine produces a further 950,000 tonnes of ore each year using a highly mechanised mining fleet of drill rigs, dump trucks and remote controlled loaders. The Macraes processing plant is capable of treating up to six million tonnes of ore per annum. At the time of its 25-year anniversary in November 2015, Macraes remained New Zealand’s largest gold producing operation, with mining and exploration permits covering a contiguous area of 15,705 hectares. The success of OceanaGold’s New Zealand operations, including Reefton, and the emergence of the Didipio gold and copper mine in the Philippines, which was mothballed for a time during the global financial crisis, saw the company awarded the prestigious Diggers Award at the Diggers & Dealers annual conference in Kalgoorlie late last year. The recent addition of the Waihi mine in central North Island to its operations and the development of its gold mine Haile in South Carolina have cemented OceanaGold’s position as one of top mid-tier miners in the world.