Chicken Nuggets to Diamonds, Copper & Gold: Air Technology Pumps-Up Profits
The world's largest mining companies have found a new technology that can inflate grades and pump cash to the bottom line. “Everyone with a copper mine is pretty excited about it.”
From the gold camps of Ontario to the diamond fields of southern Africa, the world's largest mining groups are turning to a new technology in the race to get ahead of competitors.
That technology is air, according to mining engineers and consultants. Barrick Gold, Goldcorp and a handful of go-ahead players have all begun piping, blasting and even firing gas in imaginative new ways that could alter the industry forever.
State of the art air technology has already blown open the diamond market and is “just starting” to get into gold and base metals, says a process engineer working for mining consultant Hatch, speaking on the basis of anonymity. Tonnage travelling along a conveyor can be scanned like airport luggage, before being blasted with air guns to separate ore from waste. “Everyone with a copper mine is pretty excited about it.”
The implications are mind-bending. The industry is grappling with cost inflation, wobbly prices and ever-deflating grades, but by quickly rejecting worthless rock a mine can double the metal content of the ore it handles, according to Gowest, a Toronto-based gold company that has trialled the technology at its Bradshaw mine in Timmins, boosting gold grades to 9 grams per tonne. That frees-up capacity and turns low-grade ore into valuable reserves; old mines can stay open for longer and l0w-grade deposits can swing into production.
Gold giant Goldcorp has been testing the concept at its nearby Porcupine mine, says senior vice president Ivan Mullany. Rocks are blasted by lasers and air nozzles hit valuable ore. “We need to reject waste as early as possible, before we start spending money on it.” Material can reach a “purity previously unknown,” according to one consultant in Norway.
The technology began in food processing: to stop bones, beaks and feathers going into chicken nuggets, X-rays would scan
conveyor belts loaded with meat matter, blasting offensive material with air jets.
It then went into recycling. Known as “pneumatic ejection”, constellations of high-speed air valves would pick out individual objects, pushing cartons, lids and cans into multiple channels. “You can separate your plastics from your metals,” says a consultant at Hatch. “The technology is big in the recycling space. It's also very big in the diamond space.”
In May 2015, a recycling company with facilities in Germany fitted one of its machines at the Karowe diamond mine in Botswana. Less than six months later its air nozzles picked-out a 1,100-carat diamond, the biggest found for over a century, diverting it from the main crusher and dropping it into a compartment, turning into a $53m cash bonanza for the mine's owner, Lucara.
Late last year, an identical machine was fitted by London-based Gem Diamonds at its Letseng mine in Lesotho. Having been borderline for years, the mine has since popped out 19 gemstones bigger than 100-carats, boosting cash to $70m, up from $20m a year ago.
Now mining giant Anglo American has hinted that it may also be looking at the technology in copper and battery metals.
Chief executive Mark Cutifani recently updated analysts in London on the group's turnaround: since 2012, it has halved the number of mines its owns from 68 to 36, whilst lowering its headcount from 160,000 to 95,000. Yet output is up 8 per cent, and the group's average mine life has gone from 25 to 30 years.
But the real star of the show may be bulk-sorting. A test unit that Anglo has spent three years developing will arrive at one of its copper mines in Chile this week, where it will be dropped into the mine's conveyor belt network, scanning tonnage and dumping barren rock. Anglo has kept quiet on which technology it is using, but other companies either use air guns,
vibrations, or a flop-gate to send dud rock spiralling down a “reject” chute.
“We're moving out of the lab and into the field,” said Anglo American's finance director Stephen Pearce, who also refers to the technology as “precision mining”, “P101” and “full potential plus.” Once the new test unit has been trialled in copper, it will arrive at Anglo's nickel and platinum mines in Brazil in South Africa.
“Every deposit is unique” and different rock types lend themselves to different scanners, according to geologist Dr. Toby Strauss. X-rays are good for spotting diamonds, lead or zinc, but lasers and magnetics are better at finding quartz and arsenic, which in turn point to gold.
The technology can also be scrambled: dust plays havoc with nozzles and valueless minerals like pyrite (also known as fool's gold) can trick machines into thinking it is valuable ore, because of its high atomic density. “Not all ore's amenable to sorting.”
Engineers at Barrick are meanwhile using air in other, even subtler ways. A kilometre underground at its Hemlo mine in Ontario, the company uses giant fans and propane to keep air moving. By drilling vents into adjoining shafts, its engineers have also created a new passive airflow that uses updrafts and geothermal energy to keep the mine warm in winter, and downdrafts and icicles to suck in cold air during the summer. Energy costs have dropped from $24m to $19m.
Whatever the technology, the benefits all go to the same place, says Anglo's Mark Cutifani. “That's straight to the bottom line... The new innovation stuff that we're starting to tinker with and introduce will become a much bigger part of the story in the next five years.”
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