There was one day that I had the chance to go out with the blasting crew. At Goldstrike we blast every day, and sometimes twice a day! But usually just once, at 2 0'clock. Anyway, they work hard all day filling and packing hundreds of 40' deep drilled holes with explosives. Each hole has a detonation cord that runs to the next one. The green cord is the detonation cord. This is what it looked like before the blast.
Before the blast, the holes are in neat little rows. Like this:
Then we have to run around getting everyone clear of the blast. No people can be within 1500 feet of any edge of the blast, which doesn't sound like much, but actually really is. We use the big trucks and other vehicles as road blocks so no one goes where they are supposed to. This driver wasn't quite sure where he was supposed to be.
When they blast ore, each individual hole has a microchip connected to it so that, when the blast is set off, each hole blows at the same time. This way, they know exactly where the rock falls and they can mine more efficiently. But, this blast was just for waste rock; there wasn't any ore here, so it didn't matter where the rock ended up (as long as it wasn't in someone's face). Instead of attaching a microchip to each hole, only a few holes at the top had them and then detonation cord connected all the holes after that. As a result, there's a ripple effect when the blast is set off.
After the blast, the crew has to go down and check each hole to make sure it detonated. If any of the charges are left un-detonated, it can blow the bucket right off of our shovels, which is a bad thing, considering those are multi-million dollar machines! This is what everything looks like after the blast.
Because it was so hot on the day that we blasted (about 103 degrees) a couple of the clips that keep the detonation cord in place malfunctioned. They're made out of plastic and when it gets too hot, they get soft and don't hold the cord in place. As a result, 2 holes did not blast. So we hooked up some detonation cord to those 2 holes and hooked that up to a manual detonator. I got to set that part off.
The trigger on this one is a bit tricky because it will snap that opposite way it's supposed to, so I did have a little trouble with it. But it all worked out in the end.
Good day, fun people, awesome blast!
Cool!
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