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A US 500lb bomb was blown up in the middle of Munich yesterday night. One of thousands of bombs that still are burried somewhere. I was amazed they had to blow it up in the middle of the city.

http://www.youtube.com/watch?v=_NbM2Xbc1uk

ORIGINAL: castor troy

A US 500lb bomb was blown up in the middle of Munich yesterday night. One of thousands of bombs that still are burried somewhere. I was amazed they had to blow it up in the middle of the city.

http://www.youtube.com/watch?v=_NbM2Xbc1uk

I remember back in December of last year they had to evacuate 45,000 out of Koblenz because the drought uncovered a 4,000 lb British bomb buried in the mud in the Rhine.
I think I read that said it is would have detonated it would have shattered windows up to 30 km away.

They tried to disarm it for about 24 hours before they had to give up.

Safest way, start moving it and you have no idea when it could blow.

They wrote something about a delayed fuse that uses aceton, which made it much more difficult to disarm compared to a conventional mechanical fuse.

Nice fireworks, didn't expect it to still be so visible. They'd covered it with tons of sandbags that probably absorbed the majority of the energy.

A delayed fuse with acetone? Curiosity took over and I found this... http://www.303rdbg.com/missionreports/218.pdf
Quite interesting read. I can imagine what a pain theses fuses must be after a few years. If the acetone had started to dissolve the celluloid piece, just yet not enough before it evaporated, it must be a va-banque game to tamper with such a fuse.

Very interesting read, thanks janh!

Built back in the day when "Made in the USA" really meant something. [;)]

And now, today:


Unexploded WWII bomb disrupts Amsterdam Schiphol airport


[X(]

The Germans and British were in a bit of an arms race to come up with trickier and nastier fuses for bombs to kill unexploded bomb crews and disrupt clean up efforts after raids. The Germans started loading a few "trick" bombs in every raid during the Blitz to tie up resources after each raid. The British countered with the same practice.

Some bombs were time delays and others were rigged to only go off if someone tried to disarm them. All unexploded bombs are dangerous, but if they have a trick fuse disarming today is going to be virtually impossible.

Europe has a lot of unexploded ordinance. I've heard farmers in France and Belgium still occasionally turn up unexploded shells from WW I even today.

Bill

ORIGINAL: wdolson

The Germans and British were in a bit of an arms race to come up with trickier and nastier fuses for bombs to kill unexploded bomb crews and disrupt clean up efforts after raids. The Germans started loading a few "trick" bombs in every raid during the Blitz to tie up resources after each raid. The British countered with the same practice.

Some bombs were time delays and others were rigged to only go off if someone tried to disarm them. All unexploded bombs are dangerous, but if they have a trick fuse disarming today is going to be virtually impossible.

Europe has a lot of unexploded ordinance. I've heard farmers in France and Belgium still occasionally turn up unexploded shells from WW I even today.

Bill

Keeps my company in business.

BBC has a series, DANGER UXB, on bomb disposal during the Battle of Britain. It's pretty good, and goes into the various German fuses, and advances.

The damage is in the millions, as they tried to lessen the impact with straw! [X(]

The straw caught fire and caused some serious fires in the houses nearby. The prettiest thing: The owners will most likely don't get a cent, as alsmost all fire insurances exclude "war damage"...


Why the fuck did they use a burning material to shield it, not just bags filled with sand?
Why the fuck did they bring extra explosives twice to detonate the bomb?

[:@]

read in the newspaper today that it didn't go nearly as planned.

Same in Austria, if a bomb or other dangerous war materials are found on your ground, you have to pay for it yourself which can pretty much ruin you instantly.

ORIGINAL: LoBaron

They wrote something about a delayed fuse that uses aceton, which made it much more difficult to disarm compared to a conventional mechanical fuse.

It was WWII equivalent of bunker buster bombs. It was used against industrial installation in Germany and Italy. We had a few detonated in the same way here in Rome.

ORIGINAL: Historiker
The owners will most likely don't get a cent, as alsmost all fire insurances exclude "war damage"...

Technically, is that war damage or dumb*** bomb disposal police force damage? Well, that's probably not covered either...[:@]

Situations like this are always difficult to deal with, and the decisions made are never made lightly, even though they may appear stupid or negligent to the casual bystander. Some of my observations:

The fuze - Chemical (and mechanical) long delay fuzes almost always had an anti-withdrawal feature incorporated. The reason is obvious...the fuze is accessible until detonation. For those of you with access to OP1664, look up the M120 series delay fuzes. It took very little movement to initiate the anti-withdrawal feature. How much of that movement was accomplished when the bomb initially impacted ? How much oxidation or other chemical interaction took place with the bomb over the years it was buried ? Was it exposed to excessive heat/cold or other environmental factors ? These questions are practically impossible to answer, so one must assume the worst until porven otherwise.

The staw and sandbags - Explosive effects follow the path of least resistance, and the optium direction to minimize blast/shock effect is upward. Why ? Electrical, sewage, water, comm and gas lines, subsurface structures like subways, etc. Earth does a good job of transmitting shock waves, even more if there is good solid bedrock in the area. An excellent and easy way to minimize the shock is to simply dig a trench around the item; however, this may not be possible in a heavy urban area. Straw bales, you ask ? Pretty handy for minimizing shrapnel, but yes, they can catch fire. Then again, I've set hundreds of sandbag remnants and tires on fire from shots too. So, whats more cost effective...some fire damage to houses, or collapsing a subway tunnel, or starting a massive propane gas line exposion ?

Explosives twice - Not all of the explosive may have gone on the first shot. It happens.

Dumb bomb disposal and property damage - Most truly dumb ones are members of the Order of the Red Mist. As for property damage, we are responsible for negligent work, but I've never known that to happen. As for the rest of it, thats a legislative thing, and, well....their parents/grandparents shouldn't have picked a fight.

Finally, I read recently that the French and Belgians recover something like 600 tons of chemical weapons a year from the border area. I can't imagine what the conventional tonnage is.

This may sound silly, but why did they not just leave it? Having lain dormant for 70 years or so I doubt it was going to go off anytime soon........

ORIGINAL: Miller

This may sound silly, but why did they not just leave it? Having lain dormant for 70 years or so I doubt it was going to go off anytime soon........

I'm sure that option was raised during the discussion on how to deal with it. In this case, the fuze type and function would have negated that possibility. The firing pin is spring loaded (what we refer to as a cocked striker). With no way to absolutely verify the condition of the ampoule, the metal holding the firing pin, or the condition of the spring itself, you have to assume the worst, which means it has to be dealt with right now. Another factor to consider is the explosive filling itself. A 500 pound bomb has roughly 200 pounds of explosive. Over time, the explosive will be exposed as rust will penetrate the case, and the explosive could become sensitized or crystallize due to reactions with its surrounding environment. This almost always results in an extremely sensitive compound that can detonate at the slightest movement or temperature change. Japanese ordnance is notorious for this problem due to their reliance on picric acid. Also, would you really want to leave something like that accesible to bad people ?

I don't think I've ever heard of a single item being buried again and left. It has happened on large sites, and they are often turned into state or national parks here in the US (Assateague, MD, Pax River Wildlife Refuge, Mt Rushmore, Sandy Hook and some others spring to mind).