This happened a few counties south of here. I've seen this job, it is enormous, they can't build houses fast enough it seems.
From the video it appears that the blast may have been attributed to, the size of the Blast design (to large), Powder Factor of the specific explosive used was miscalculated causing the blast to be overload, drilling pattern and or design (drill hole spacing, drill hole burden errors), rock geology anomallies, lack of sufficient Blasting mats (to few, material not used for the mats not strong enough to absorb the blast energy released may have ripped or holes punched through) This type of blast in Urban areas, is to be designed to break the rock, not to up-heave and throw the rock. The function of controlled Powder Factor, proper pattern, accurate drilling and blasting mats are to control the blasting material, preventing it from moving off the blast site. Unfortunately urban blasting does come with many challenges
My goodness.
Opening up the drill pattern to speed up the job while reducing costs may have backfired so to speak
Oh wow, massive damage.
I'd imagine their insurance is going to go way up. Maybe they should change the name to Neil's UN-controlled blasting. You would think with blasting being very common in quarries for decades it would almost be a perfected science. Even Controlled Demolition that implodes buildings has it down to a science. They have a couple video's of Las Vegas casino's they've imploded. I watched a short documentary on them on Discovery Channel I think. The head guy Mark Lazeau(sp) knows what he's doing. Pretty impressive what they do. Implosion's aren't usually allowed here.
Yes there is a lot of engineering involved in implosions, calculations for the weakening of the structural supports, calculations for the load factor, placement and type/style (shaped charge to cut metal beams) for the charges as well as timing sequence. Lots to do to make it work the way it is designed. That’s why they have big insurance coverage and get the big bucks.