Ten UAVs have been lost since South Africa’s Gold Fields, the world’s seventh-biggest gold producer, began operating the Trimble UX5 systems at its St Ives operations near Kambalda.
One crashed as a result of human error, while nine have been taken down by wedge-tailed eagles, which are known to have wingspans more than twice that of the 1-metre-wide UAVs.
The UAVs are constructed from foam and carbon fibre, and fly at an altitude of about 125 metres, reaching speeds of up to 92km/h.
Razor-sharp talons have turned the wedge-tailed eagles into what St Ives Mine surveyor Rick Steven calls “the natural enemy of the UAV”.
“Eagles are extremely territorial birds,” Mr Steven
“Seeing a UAV in the sky, obviously they consider it a threat and something that’s encroaching on their territory.”
Mr Steven told 140 delegates at the Australasian Institute of Mining and Metallurgy’s Open Pit Operators’ Conference in Kalgoorlie-Boulder yesterday the introduction of UAVs was the biggest step forward for surveying since global positioning systems (GPS).
The UAVs capture large-scale photographs, down to 2cm resolution, and computer-generated, high-detail contouring of mined areas that are incorporated into future plans.
Mr Steven, who considers drones a “derogatory” term for the UAVs because pilots must pass a five-day course to fly them, showed delegates at the conference a recent photograph of an eagle attacking a UAV mid-air.
“People couldn’t believe I was able to get such a good photo of an eagle airborne, but I didn’t … another eagle took that photo,” he said.
“I was flying the tailings dam out at St Ives and I was getting attacked by two eagles simultaneously.
“I know the eagle loves to fly on thermals. Because they’re a big heavy bird, and the more thermal activity there is, the easy it is for them to fly. Thermals activate during the hottest part of the day — which is why we’re flying first thing in the morning now,” he explained.
“That’s been really successful. So if we fly first thing, say 6:30 a.m., we can get our flight done. Modus operandi on site; if I see an eagle in the air, I call off the flight.”
For future commercial drone operators that happen to be sharing the air with a watchful eagle, you have been warned.