Not known for its natural resources, New Zealand does produce significant quantities of coal, ironsand, aggregates and gold, much for internal use. Gold, however, is exported and New Zealand produces around 350,000 ounces a year from its Martha Hill mine in Waihi, Coromandel, and from the major producer, Macraes Mine, at Macraes Flat, inland from Palmerston, in Otago.
The Macraes Flat gold rush began in 1862 after James Crombie found gold in the Deepdell Creek. Alluvial (loose) gold ran out quickly, however, and the rush lasted only 15 years. After a short respite, underground mining continued to extract profitable quantities of gold until the 1930s. This then petered out, and the mine finally closed in 1954.
Extraction techniques improved over the years, and in 1982 the area was again explored. The mine reopened in 1989 and, since then, more than 31 tonnes of gold has been extracted.
Macraes Flat is an open-cast mine. Open-cast mining destroys the land. Hills have been opened up, exposing bare rock, with pits dug down to many metres deep. Huge Caterpillar earthmovers crawl at the bottom of these pits, looking like toy trucks. They in turn dwarf normal vehicles such as a Hilux ute, attesting to the scale of both mine and vehicle.
Extraction of the gold is a ruthless process. The rock is pulverised to get at tiny amounts of gold that are chemically bonded to it. Around 190 tonnes of rock produces just 30mg of gold. The process produces masses of sludge that is held in containment ponds.
The mine is operated by Australian mining company, OceanaGold. It has a commitment to restoring Macraes Flat to its natural state once extraction is complete. This is not just good corporate citizenship, but a requirement of New Zealand’s Resource Management Act. OceanaGold appears to take their commitment very seriously and has begun restoration with a wetlands area, a manmade pond, a trout hatchery and educational programme, backfilled pits and hills of tailings that have been covered in topsoil and replanted.
The gold will take around 35 years to run out. There is no estimate regarding how long the restoration will take.