A Tour of the Argyle Mine

“It was with no shortage of security that Chris and I toured the Argyle Diamond mine near Kunnanurra in the East Kimberley earlier this year.”

We were forbidden to pick up anything from the ground and with a 42 carat diamond being found in the tread of one of the ore trucks in 1991 we could understand why. If you were to pick up anything from the ground you would be subject to a ‘robust’ search. One creative worker tried to bring in his pet pigeon to work one day. It panned out to be his pet homing pigeon. He was stood down before he was able to sticky tape a couple of the precious pebbles to the birds feet.

The mine produces around 30 million carats of Diamonds each year, which accounts for around one quarter of the diamonds mined annually in the world. It is little surprise then that the mine works 24hrs a day for most of the year.

Argyle Diamonds formed in the intense heat and pressure deep inside the Earth’s mantle some 2.5 billion years ago. In 1976 a geologist from Rio Tinto found Diamonds in Smoky Creek, but had to wait 7 years for an existing claim over the land to expire. On the day the existing lease expired, Rio Tinto pegged the claim on the largest diamond pipe in the world. Needless to say, the previous owner was not particularly happy!

The pipe is roughly cylindrical in shape, so the deeper they mine, the more dirt or ‘overburden’ they have to remove. This year marks the switch from open pit mining to underground mining, extending the life of the Argyle mine for another 10 years. Once the underground mining is completed they will cease operations still leaving plenty of diamonds too difficult to reach still buried deep in the ground. But don’t think that you will be able to head out with you pick and shovel and make a mint, the surface and tailing pile will be totally revegetated and the mine pit left to fill with rainwater and become a 1km deep lake.

This story was taken from Holdsworth Bros newsletter ‘Pearle’ Spring 2008