Narration: Diamonds have been treasured as gemstones for over two and a half thousand years. Today the precious stones are as popular as ever.
They’re a billion-dollar industry, and the biggest diamond mine in the world is here in Australia.
670 million carats of diamonds have been recovered from the Argyle mine since it opened in 1983.
But the diamonds are running out. The open cut operation will soon have to move underground, and the flow of gems will fall to around half of current production.
Professor William Griffin: Australia and the world need a lot more diamonds. At the moment, in terms of gem diamonds, the gap between supply and demand is rising very rapidly all over the world. And so it’s not just Australia that is running out, it’s everybody.
Narration: To help satisfy the world’s taste for diamonds, mineral prospectors are on a quest to find a new source of the hidden gems.
Kevin Wills: They’re just about the hardest thing in mineral exploration to find. But hard as they are to find, they also are the most profitable to mine so hopefully those that eventually persevere and find diamonds will benefit out of it.
Dr Paul Willis: The hunt is on for Australia’s next big diamond deposit. But there’s a hell of a lot of Australia to explore. A new theory should help to narrow down that search.
Professor William Griffin: It all started out with trying to develop new technology that would help the diamond exploration industry to find more deposits. What we are really interested in, is the nature, and the composition and the structure of the deep earth.
Narration: Dr William Griffin and his team at Macquarie University are investigating how diamonds form 150km below the earth’s surface.
Professor William Griffin: The best samples that you get of the deep earth, are things that come up in volcanoes and the deepest volcanoes are the Kimberlites that carry diamonds.
Narration: Kimberlite volcanoes bring the diamonds from deep under ground, up to the surface.
Dr Craig O’Neill: We can’t mine two hundred kilometres down ourself unfortunately, so we have to let the Earth do all the hard work for us. So Kimberlites act as a diamond elevator, they pick the diamonds up from down in the basement where they’re formed, bring them up to the surface where we mine them today.
Professor William Griffin: They come up to the surface and along the way they have ripped off bits of rock from the walls of the conduit, and in those rocks there are diamonds.
Dr Paul Willis: And do the diamonds come up loose or are they in rock? How do they look when they get to the surface?
Professor William Griffin: Well if you find a kimberlite you can see fragments of the mantle and sitting over here you can actually see a nice little diamond.
Dr Paul Willis: So that’s actually a diamond?
Professor William Griffin: That is an ugly diamond. But for example, here is another piece of Kimberlite from the same pipe and you can see it has a very nice diamond sitting there in it. So then when we find this Kimberlite, we can mine it, crush it up, and take out the diamonds.
Dr Paul Willis: But diamonds aren’t found in every Kimberlite, is that the problem?
Professor William Griffin: No that’s the problem. Ninety per cent of Kimberlites contain either no diamonds or uneconomic amounts of them, so the trick is to find the ones that have come up through a zone of the mantel where the diamonds are formed in the first place and that’s where we’re making some strides is understanding that.
Narration: To identify where to look for diamonds, it helps to know how they’re formed. The history of a stone can be revealed using a process called laser ablation.
Professor William Griffin: When you zap the diamond with the laser, you’re analysing the fluids from which it grew and so we hope that by understanding the nature of those fluids we can find out where they came from, how they deposit the diamond and why they deposit the diamond in particular places.
Narration: While William’s team are looking intensively at diamonds and rocks, their colleague Craig has come up with a completely different approach.
Dr Craig O’Neill: We’ve set up a continent that is very, very similar in structure to what we think Australia would be…
Narration: Craig has developed computer models that show how the Earth might have evolved over billions of years.
Dr Craig O’Neill: Right in the centre of the Earth, heat coming out of the core, heats up the rock above it. And these rocks rise as really thin columns of material up through the Earth’s mantel and we call these plumes.
Narration: These simulations have a valuable spin-off… they predict the best places to look for diamonds.
Dr Craig O’Neill: Some parts of the continent are thick and you can see in those regions we tend to have diamonds, whereas some parts of the continent are quite thin and we have no diamonds in those regions. The best part to look is actually in this transition zone between the two where it goes from a thick part of a continent to a thin part of the continent.
Dr Paul Willis: And so this is the new prospector’s map for diamonds in Australia?
Dr Craig O’Neill: It could be if all things pan out. Now the places we are predicting should have good potential for further diamond mines occur right on this edge where it goes from being thick to being thin. When we plot up Australia’s actual diamond occurrences our predicted diamond zone and our observed diamond occurrences line up really, really well. So this really gives us some good ideas about where to look next.
Dr Paul Willis: Having a new theory is all well and good but you’re not going to find new diamonds unless you go out in the field and start looking for them. That’s exactly what they’ve been doing here in the Flinders Rangers.
Dr Kevin Wills: What we do is go in and collect stream samples and then if you find diamonds or indicator minerals we can trace them back to their source.
Narration: Kevin Wills wasn’t aware of the work being done at Macquarie University when he took out his exploration leases. His company has been prospecting both the old fashioned way, and using more sophisticated electro-magnetic techniques… And what they’ve found backs up Craig’s theory.
Dr Kevin Wills: Well Paul, this is exactly what we’ve been looking for this is the K7 Kimberlite.
Dr Paul Willis: So this is the kind of rock that has the diamonds in it?
Dr Kevin Wills: Yeah that’s right.
Dr Paul Willis: And, have you had any luck finding any diamonds in this yet?
Dr Kevin Wills: Yes just recently we found these diamonds.
Dr Paul Willis: Oh, look at those.
Narration: The results are promising, but they’re not good enough yet to start a mine.
Dr Kevin Wills: We’ve got to get at least probably ten times as many diamonds as we found in this particular sample. But it’s actually very difficult to find any Kimberlites. And in the past two years we’ve found seventy-five of them. Twenty-one of them have got diamonds in too so we’ve got plenty of things to follow up. So we believe that if we keep at it we could have a bit of luck and end up finding a new diamond mine.
Narration: The work they’re doing at Macquarie University takes a little bit of the luck out of the equation, by identifying up front, the areas that are worth exploring.
Dr Craig O’Neill: Diamond exploration costs a lot, in order to find one little Kimberlite pipe across a whole continent is a lot harder than even finding the needle in the haystack. To think well here we are, predicting wildly, and sure enough they have actually found something in exactly where we said people should be looking, so that’s a nice feeling.
Narration: And with more than half a billion dollars worth of Australian diamond exports on the line annually, the stakes are high. Story Contacts
Dr Craig O’Neill GEMOC Division of Environmental and Life Sciences Macquarie University NSW 2109
Professor William Griffin GEMOC Division of Environmental and Life Sciences Macquarie University NSW 2109
Dr Kevin Wills Flinders Diamonds 20 Boskenna Ave, Norwood, SA 5067
Joakim Opostolas Delphi Diamonds Level 8, Suite 10, Ashington Place 250 Pitt St, Sydney NSW 2000
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