Model Boat Mayhem
Mess Deck: General Section => Chit-Chat => Topic started by: polaris on November 20, 2008, 09:10:22 pm
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Dear All,
Someone has expressed an interest in seeing something about this, and, prompted, I post these Links so that you can see where your metals come from! - it all started from ESP TEST! :}
Regards, Bernard
http://uk.youtube.com/watch?v=44tm26Fhqr8&feature=related
http://uk.youtube.com/watch?v=xHldEwMvY70&feature=related
http://uk.youtube.com/watch?v=9DmUitYmxIM&feature=related
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WOW !!!!!!
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Tis, isn't it! :} The last Link is my preferred 'the perfect' sequence... something that is always sought!
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Whilst I know little about coal, this is an excellent example of how not to take coal out of the ground! Our friends across the pond are ever enthusiastic, and take great pleasure in doing things impressively! :}
http://uk.youtube.com/watch?v=XM2TbddOhN0&feature=related
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For those of a more underground nature(!), this is an example of Gloryhole mining. If you look closely inbetween, you will see where the u/g workings are getting to the face, and where the 'stuff'/ore is falling. The 'stuff' is falling down into underground hoppers, being drawn off, and then taken to the surface in the normal mine way. A 'Gloryhole' is where the upper zones are removed opencast, but, when the depth becomes such that overburden becomes excessive by %'age, that part of the ore body that remains is taken out from underground. There are far better examples of this, but this ill. is a good way of showing what it means. If you are wondering how they do this, it's by long shot holes being drilled from a sub-level or tunnel up or down into the know ore ground, and by utilising stage packed holes (or 'air blasting'), to get a thorough hole length timed detonation/rock shift.
http://uk.youtube.com/watch?v=G4z-xUdroys
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And then I progressed into RC warships!!! {-) :-)) - if only I could get 1:96 6" guns to fire to scale!!! {-)
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If one must blast coal out of the ground, this, in comparison to the last demonstration is really the better way! :-)) :}
http://uk.youtube.com/watch?v=taogUY9qXsQ&NR=1
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Interesting. If you look closely at some of the sequences you can see the Detcord, or whatever they call it these days, flashing between the charges.
And an explosion like that coal dust fireball is what is reckoned to have done for the Lusitania.
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Interesting. If you look closely at some of the sequences you can see the Detcord, or whatever they call it these days, flashing between the charges.
And an explosion like that coal dust fireball is what is reckoned to have done for the Lusitania.
"shock line" is one term i've heard.
but that coal dust blast, wow WHAT A BLAST!
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Aw these guys are professionals, here is one of the dumbest things I have ever seen amateurs do, and if this was not enough they tried the same thing with a ship (the New Carissa) and did not do any better with it. O0 O0
http://uk.youtube.com/watch?v=hvha8N3a28U&feature=related
Enjoy
Andre
over yonder in Portland Oregon where we blow whales UP O0 O0
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Dear Jonty,
I have great admiration for the technicians who have to connect those sequences of 100's of holes up - and the smaller complicated ones as well. To see those lines going off in perfect sequence will be very satisfying to those put them all together! - and relief when those really big rounds were initiated (a few hidden fingers were crossed somewhere!). I was not involved with such large scale work, and have anyway been out of things for fifteen years or so: so, whilst the principals are known, I was overtaken by technology long ago! - things progress ever rapidly now as well obviously.
Coal dust explosions need a significant amount of suspended dust to occur, and invariably need flame to trigger them. It is long established that gas explosions in collieries triggered dust explosions (sometimes these secondary explosions were worse than the initiator): the gas explosion blast picking up dust and the fire of the gas obviously setting off the dust... once taken the whole lot would 'roll along' -very very unpleasant. It didn't take long for the mining technologists to work out solutions: the spreading/laying of limestone dust in underground roadways being the first main solution. However, the best solution was/is to get to the dust at the point of creation, hence water sprays/misters effectively did away with this particular problem.
As to a ship suffering from a coal bunker dust explosion... not impossible, but the conditions and sequence of events would have to be 'perfect'. That fireball on the Link was, as obvious, due to a huge amount of dust being thrown into the air at once, which, being 'chased' by the fire of the explosives could/would only do one thing! Impressive all the same, and entertaining(!), but not quite 'good practice'!
Regards, Bernard
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Polaris
I find a good way to make guns fire is to use the firework from a party popper. Its cheap, it's loud; and its simple... if you want more smoke add some talc on top of the firework [ all you need to do is lead the string out of the breach of the gun and rig something to pull it I've used survo's ; motors; elastic bands and or springs to set mine off; sometimes one or two guns sometimes a whole broadside]
Freebooter [Jimmy] :-))
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Dear Jimmy,
Thankyou for your reply. I can see what you mean, but unfortunately it's not practical as dimensions just don't permit or suit.
Regards, Bernard
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Thanks for the info, Bernard. The theory about the Lusitania was that the torpedo damage probably would not have sunk the ship alone, but their striking nearly empty bunkers (the ship was almost at the end of its voyage) stirred up the coal dust, and it exploded.
I'm no fan of conspiracy theories, but apparently the hull damage was more than would be expected of the relatively weedy torpedoes of the time. It was long rumoured that the ship was carrying munitions, but no evidence was found to back this up, hence the coal dust theory.
Jonty
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Dear Jonty,
What you say re the Lusitania bunkers could indeed be possible... large open space, exposed dust, big initiator, clouds of dust, flash and boom. Quite possible.
Re her carrying munitions. She was. I have actually held (about ten years ago), a shell timer raised from the wreck.
Regards, Bernard
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hi there Jonty. Dust explosions are no laughing mater. I work for a company that has kit that suppress dust explosions in industry . I have seen photos of building that have been riped apart from dust explosion. So on Lusitania it could have happened . The torpedo hits causing a bang ,shaking the ship which in turn would case any dust in an empty hold to stir up this might have the property's to form a dust cloud. If so and there was an ignition source her hull would have been blown clean open no problems.
john
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Used to do the plumbing for a flour mill some years ago.
No blow lamps allowed until area of work approved by management. Could sometimes take a week of prep by mill staff before we could do anything. Up to one inch pipe we used all compression fittings it was cheaper.
Colin H.
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Dear Colin H.,
Just noticed your Post. Fine sawdust can be as about as flamable as well - easy to test. Remember years ago being around-&-about in a saw mill somewhere where the dust was being blown into an area for recovery/disposal. People around wearing masks, but going into convenient corners for a smoke - lighting up with matches and lighters. Doing my best not to sound 'interfering', mentioned in passing about fire/dust, "oh, no problem, we are careful", no I said, "not that kind of fire... the dust catching when you light up"; "no, that won't happen it's damp". So I left it at that! Five months later there was a 'brief flash" that singed a few eyebrows - HSE were upset and things changed!
Regards, Bernard
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reminds me of the army commercial which goes like - join the army, where else do you get to blow things up and get paid for it? um.. i dunno where to start..