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Blasting Bedrock to Create the Foundation

Bob meets with blasting contractor Alan Dyke and takes a close look at the drilling rig as Alan and his crew prepare the site for blasting. The drill uses a button bit with carbide buttons set in steel. The holes are drilled five to six feet deep, down to the bedrock. With the final hole drilled, Alan shows Bob the emulsion stick, explosive chemicals with aluminum added for weight and a mercury cap that explodes when electrified. With the explosive placed into the hole and covered with peastone, Alan gives Bob the honor of detonating the blast.
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Blasting Bedrock to Create the Foundation

  computer-generated transcript - may not be 100% accurate

" Bob, this is Alan Dyke."

" Hey, Alan."

" Hi."

" How are you?"

" So I've never gotten this close to 1 of these drilling rigs. Is this what the bits look like?"

" Yes. This is what they call a button bit."

" A button bit."

" Right."

" And those are button shapes. What are they made out of? Steel?"

" No. those are made of cardboards."

" Ah hah. So that's set into the steel."

" Right."

" And does this just go up and down or----"

" Yes. On the end of a steel, whatever lengths of rods you wanted it in."

" Uh huh. Does it rotate?"

" Yes. It spins in there."

" Yes."

" Okay. And how does the machine itself work?"

" The hammer goes up and down on this----"

" On a chain."

" on this chain, which is worked by air."

" So you've got a compressor that's providing a certain amount of pressure."

" Right."

" And then there's also hydraulic component?-Right. Air over hydraulics."

" I see. Alright, it's gonna be real noisy so why don't we start it up?"

" Okay."

" Okay. So this is the last hole, Alan, and that's what? About 5 or 6 feet down to the bedroom?"

" Yes."

" Okay. That's why dynamite was a red stick."

" Well, you can buy it, but it is so"

" cap, and then----"

" Then we'll have a chip here."

" There you go."

" Pulse this hole with less water."

" Oh yeah."

" You hid my well."

" We found a little water right amidst the rock down there. Now what's to keep this from just blasting straight up, Alan?"

" Well, we have to use it's what they call a pea stone to lay it on top of it."

" Blasting contractors have to be sure that everyone is out of the area and accounted for before setting off the explosives."

" All set."

" So this is what will set it off, right?"

" Yes. It's called a detonator."

" A detonator. That's a battery central."

" Battery, yes."

" And that's gonna send a little electric charge through these wires, and everything will go pop."

" Okay, press the charge."

" So 1st, you have to charge it a little bit until your light goes off."

" There. You're all set."

" Can I do it?-Yes. Just push that right off."

" Push that off."

" Yeah. Right now."

" Here goes. Boy, this is pretty impressive."

 [-]


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