Get to the bottom of it’... It’s the nice slogan for thought-provoking tours of the giant Martha Hill opencast mine at Waihi.
While debate continues to rage over mining and where it should be allowed, this is a chance to see exactly what happens in one of the country’s biggest open pit operations, run by Denver-based Newmont Mining Corporation.
This is no half hour PR exercise, but a close look at the stages involved in extracting precious metals from the rock – surprisingly close to Waihi, population 4,500, a town indeed with a ‘heart of gold.’
Mine tours leave from the Waihi Visitor Centre in Seddon Street, near the magnificent 1903 Cornish Pumphouse, that sits on the skyline as the mining town’s new landmark. It was shifted at a cost of $4.2 million by Newmont, from a risky, unstable spot closer to the pit.
The fact-filled tours touch on lots of key milestones in the development of a town shaped by mining since the raw days of the 1800’s. The tours are refreshingly - far from a propaganda exercise - run by Vision Waihi Trust, not the company. And while obviously pro-mining, guide Murray Elliot, a good-humoured, long-time local whose grandfather arrived from Cornwall to work in the mine, doesn’t duck environmental questions. He points to some of the many regulations (and significant bonds), which prevent the company from walking away from environmental problems. And he outlines a wide range of environmental rehabilitation measures.
Over half a million native plants grown in Newmont’s own nursery have been planted around the mining operations. The tailings dam has a ‘non toxic’ lake that’s home to a healthy flock of water fowl, and the company has its own project to help breed endangered New Zealand dotterel. All the water from the various processes is laundered by a high-tech water treatment plant before it’s finally discharged into the Ohinemuri River. And Newmont’s plans for the pit itself centre on the creation of a landscaped lake.
We learn also, that the mine of course, is the town’s major employer providing jobs directly for 350, and many more who provide Newmont with goods and services.
First stop on the tour is a viewing platform with a hawk’s view of a breathtaking hole in the ground, 260 metres deep, and over 700 metres wide. The pit is so large that over-sized dump trucks hauling tonnes of ore look like Tonka toys. “Incredible – in the middle of town,” exclaims an elderly English tourist, a little inaccurately.
An immediate surprise is the lack of high-decibel industrial din, and dust clouds from the mine’s workings. Diggers and trucks are not permitted to produce more than 55 decibels in daytime – far less than a group of school children at play, our guide notes. Water trucks constantly damped down the dust. It takes around 20 minutes for one giant truck ($2 million-plus price tag) to crawl slowly back to the surface with 90 to 100 tonnes of ore for processing. The ore will yield 9 teaspoons of gold, and 90 of silver.
At the pit-edge, behind a large safety fence, Murray Elliot tells of Waihi’s early days. In that era of hard, dirty, laborious work, Murray Elliot explains, miners ‘worked around’ the early compensation system for a lost digit – which worth 400 pounds, enough to buy a miner’s cottage. ‘Those desperate enough had their mates cut their thumbs off to obtain the compensation.’ They called them the ‘thumb houses.’
While the spectacular open pit grabs media attention, Newmont also operates Favona, an underground mine nearby, where 40 odd workers spend 11 hours underground at a time. We are shown an escape hatch (but there are 3000 steps to clamber up from the mine tunnels).
Extracting the gold is a technical process of several stages, that involves the use of a weak cyanide solution to dissolve the gold and silver, and then carbon granules the gold and silver attaches itself to.
At the end of the process, amid tight security, a muddy sludge dried to a powder is smelted at 1100 C to produce ‘molten lava.’ The bars produced, a mix of gold and silver, weigh around 20kgs and are worth from $100,000 to $280,000. The gold bullion leaves the site under ‘top secret’ conditions, says Murray, ‘I’ve never seen it.’ They are sent to a specialised industrial mint in Perth where the two metals are separated.
(Editor Grant Dyson visited Martha Mine courtesy of Waihi Gold Mine Tours)
It takes just over two hours to drive from Auckland to Waihi, or just under an hour from Tauranga. Waihi Gold Mine Tours cost $25, departing from the Waihi Visitor’s Centre, 126 Seddon Street. Tel 07-863 9015, www.waihi.org.nz