Monday, June 05, 2023

Earth-movers, Dangerous Mining Blast Process

VIDEO HERE (10:05 minutes)


Rare Look Inside an Open-pit Blasting Process

VIDEO HERE  (7 minutes)


  1. There's an area in southern OK where I35 goes through deep cuts through the Arbuckle Mountains. One night, during some nasty storms, a bunch of rock broke loose and fell onto the highway.

    By next day they had one lane clear each way, but aside from the cleanup the engineers found the bluff faces so damaged by rain/snow/freeze/thaw over the years that they were going to have to do a lot of blasting to break off damaged rock and clear it out. So for weeks traffic would suddenly be stopped, they'd finish setting up and do the blasting, then clear off the rock, make sure the lanes were clear, then open them.

    1. That's Highway 1 in Big Sur after every rain or strong wind.

      One memorable event was when a boulder the size of a D6 sat blocking the entire roadbed. It took several weeks of repeated blasting to clear away. CalTrans apparently doesn't know how to blast, they finally called in the Army. Earlier blastings damaged the roadbed instead of the boulder.

    2. That must have been a while back. CalTrans now has its own blasting crew(s).

      There was a good sized rock slide not long ago on Echo Summit near Lake Tahoe. CalTrans had it cleared in pretty short order. I was impressed. And believe me, I'm no fan boy of Caltrans. But I do like to give credit where it's due.

  2. I used to work at the largest underground mine in North America, high in the Rockies. "Huge" hardly described the place, like a city above and again below the ground. They showed us a film during orientation, it was of the first development shot for the open pit in the Sixties, which sat high on the mountainside above the underground mine. They evacuated the mine camp, dismantled the camp town and moved it to the town twelve miles away. They set off the shot, rocks rained down on the town, and the explosion registered on the seismographs in Boulder. I started there in the late Seventies, the pit had grown huge by that time, plus the underground had grown too. They developed a new record shot in the open pit in the early Eighties, drilling and loading for weeks, hundreds of tons of high explosives. Not only did they not evacuate the site, they set off the shot mid shift--the idea being that the pit would contain the shot this time. We knew it was coming, but still--when it went off it was like being inside a huge bell when it rang. The shock wave struck big time first, coming through the rock like a huge THUD, then the sound followed afterwards, BOOM.


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