Quarry blast video - what do you think?

**El_Diablo** · 4 November 2008, 18:07

Originally posted by wxman View Post

Posted here in "General" as I could not think where else to post it - not technical

As it happenes, just 3 miles away from home is the largest granite quarry in Europe. Most days at 12:30pm I feel and can often hear a blast as they remove rock from the quarry. I approached the Quarry to see if I could film the blast for inclusion on my village weather web site.

On Monday I filmed a blast that uses 6 metric tones of explosive but I also have the opportunity to film another blast tomorrow which will be a full 8 metric tonnes of explosive.

Can you look at the video that I have shot and suggest improvements? I do have a problem with the shock wave moving the camera tripod, hence the reason why it looks out of focus for a few milli seconds – Also I said “Wow! During the blast - which IMO has ruined the shot.

http://www.ukweatherworld.co.uk/stu/qBlast.wmv (8mb) [reduced in size from HD for the web]

Wow!

Yes, you need to remove yours from it, if you can.

**EqualOpportunities** · 4 November 2008, 18:27

Originally posted by wxman View Post

Posted here in "General" as I could not think where else to post it - not technical

As it happenes, just 3 miles away from home is the largest granite quarry in Europe. Most days at 12:30pm I feel and can often hear a blast as they remove rock from the quarry. I approached the Quarry to see if I could film the blast for inclusion on my village weather web site.

On Monday I filmed a blast that uses 6 metric tones of explosive but I also have the opportunity to film another blast tomorrow which will be a full 8 metric tonnes of explosive.

Can you look at the video that I have shot and suggest improvements? I do have a problem with the shock wave moving the camera tripod, hence the reason why it looks out of focus for a few milli seconds – Also I said “Wow! During the blast - which IMO has ruined the shot.

http://www.ukweatherworld.co.uk/stu/qBlast.wmv (8mb) [reduced in size from HD for the web]

Ah yes - Buddon Wood (I think) - it's a fair old size. That is some impressive filming fella.

**bogeyman** · 4 November 2008, 18:31

Astonishing.

Illustrates the power of modern explosives very graphically.

**milanbenes** · 4 November 2008, 18:34

cool, yep the wow needs to go, but what are the kind of electrical thunderbolts which go across the ground at the beginning, is that to make it look more scifi ?
Milan.

**bogeyman** · 4 November 2008, 18:39

Originally posted by milanbenes View Post

cool, yep the wow needs to go, but what are the kind of electrical thunderbolts which go across the ground at the beginning, is that to make it look more scifi ?
Milan.

Could be the piezoelectric effect.

Compressing large masses of stone, very suddenly, will generate very high voltages - though I would have expected the 'thunderbolts' to be blue rather than yellow. Probably just the flash from the charge detonation.

**wxman** · 4 November 2008, 19:09

Thanks for the comments so far (more welcome) and yes this is Barden Wood Quarry – Mountsorrel – how did you know ??

This first shot was really a warm up shot – tomorrow is the real deal! I plan to tripod mount the camera closer to the blast and then retire (fitting really on bonfire night don’t you think?) so this will remove any “wow” comments from my self – believe me at the time I really could not contain myself.

I could do with some thing that describes the scale of the blast – this will be tough to do unless I capture a truck / person near to the blast site before the event occurs and use this as a reference.

As an aside, the explosive used is actually a liquid! Poured over the detonators which are buried @ 20 meters deep. The flash that can be seen is on top of the explosive bore hole, of which there about 40. Each blast timed to occur 8ms after the last to reduce the shock wave.

Before each blast the rock face is laser and GPS mapped and sonically probed to ensure that the blast will dislodge rock and not blast upwards. I remind you that 6 tonnes of explosive was used in this blast, which shifted some 300 – 400 tonnes of rock! The scale does not really show up in the video.

In comparison the Canary Wharf explosion( 10 Feb 1996) was just 0.5 tonnes and created immense damage because it was not contained. Also typical WWII bombs were 500lbs (0.2 metric tonnes).

The blast that I filmed was the equivalent of 30,000 WWII bombs going off in one location (blast was contained with granite)

Cant wait to see the 8,000 Tonne explosion tomorrow - will post video.

Sure beats a day away from the office coding C#

**NotAllThere** · 4 November 2008, 19:37

WOW

The original shot was too short, must last longer. When you cut to the slower-mo, make sure there's not too much of nothing happening.

Seriously cool. I envy you.

**Moscow Mule** · 4 November 2008, 19:42

You should ask them if you can put a crash test dummy on the top of the blast to get some scale...

**wxman** · 4 November 2008, 19:45

Yes I agree, I will deal with this in the edit - I think that running through the real time blast twice would be better and then dropping the * 5% time laspe but keeping the 20% time laspe - I think that I need to add a few more frames to the backwards forwards section at the end

Cant wait for the 8 tonne blast tomorrow

Will post video here.

Quarry blast video - what do you think?