Here is everything from the old thread:
tahoe27,
Subject: Syar Rock Quarry - LHR Sat Mar 09, 2013 1:25 pmThis rock quarry on LHR has been there since the 60's.
I always found in interesting considering Zodiac's "bomb". Blowing up a pile of gravel....
morf13,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 1:48 pmOne of tehse thread has more about that quarry Tahoe. I forget where,I think its the James owen thread because he had worked there,or it came up with one of his addresses.
tahoe27,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 2:13 pmYes. I know we've discussed it. Thought it worthy of its own thread.
I think a lot of folks think of a mechanical bomb when they think of what Zodiac wrote. But, of course, he wrote of blowing up a pile of gravel. While it could have simply been something he read about, I find his mention of this unique in a sense. Most would think of a different type of "bomb". So, what led him to gravel? Sounds like an old mining trick.
morf13,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 2:51 pmCertainly interesting with the whole Lake Herman Rd location,etc
traveller1st,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 4:13 pmtahoe27 wrote:Yes. I know we've discussed it. Thought it worthy of its own thread.
I think a lot of folks think of a mechanical bomb when they think of what Zodiac wrote. But, of course, he wrote of blowing up a pile of gravel. While it could have simply been something he read about, I find his mention of this unique in a sense. Most would think of a different type of "bomb". So, what led him to gravel? Sounds like an old mining trick.
I'm not sure what part of it you see as a trick T. To me the gravel is simply added to provide shrapnel to increase collateral damage to the blast itself. Much like the idea behind a nail bomb only larger.
You are right that the bomb itself isn't mechanical - it's just the over complicated and impractical trigger mech that's the 'mechanical' part as you noted on the copper leaf spring thread.
The bomb itself, as far as I can see is however, very much a bomb. At least in part. Actually I should say bombs as he proposed a string of them. I say in part because according to this page
http://cdn.preterhuman.net/texts/wars_a ... s.htm#ANFO ammonium nitrate bombs require a TNT booster to detonate them or a sufficiently similar high yield charge. Something I don't see mention of in Z's description.
Ammonium Nitrate Explosives AN-FO and AN-AL:
Ammonium Nitrate is arguably the single most important chemical in improvised explosives production. It may be manipulated in various ways not only to form explosives but also to be converted into various other chemicals useful in this work. Even if it weren’t so easy to procure (it is widely available as a chemical fertilizer), it would still be an invaluable material.
The most basic AN explosive is called AN-FO (Ammonium Nitrate/fuel oil). AN fertilizer comes in the form of prills (pellets) that can be mixed in a proportion of 96% AN and 4% fuel oil to form AN-FO. The only problem with AN-FO is that it requires a booster of about 1 LB of TNT or its equivalent to detonate. It is best if the booster is in the form of a short, squat cylinder, like a food can, rather than a stick.
AN-FO has been in commercial use as a blasting agent since the 1950s and remains in very widespread use. It has found most covert use in car and truck bombs (i.e. Oklahoma City) where it is used in very large quantities. A cement mixer should be used to prepare large quantities of this explosive. The AN is poured into the mixer with the required amount of fuel oil (100lbs AN per gallon of fuel oil if powdered AN is used, or ½ gallon if prills are used). Tumble the mixture for 20-30 minutes, or until a homogenous mixture is obtained. AN and moisture react to quickly rust metal, be sure to wash any metal equipment well after exposure to AN.
Powdered AN in this mixture will yield greater power however this will probably be limited to very small quantities as the time it would take to grind hundreds of pounds of AN into powder would be prohibitive. If a box of commercial laundry detergent is added to the mix (1 LB per 100 lbs. of AN), the performance of the explosive can be substantially increased (as much as 30%). 2 lbs. of aluminum powder will increase power even more.
Pour the mixture into charge containers, add the booster charges and seal. The larger the booster the better. A 55-gallon charge container will require about a 10 LB booster for positive function. If possible, place the booster as near to the center of the charge as possible. A good, strong booster can accelerate the detonation speed of the main charge substantially; a weak booster can reduce it.
Another high explosive made from ammonium nitrate is AN-AL (ammonium nitrate/aluminum powder). This is a very simple compound requiring only mixing of 4 parts finely powdered AN with 1 part aluminum powder and resulting in a very powerful explosive. The AN must be powdered and then all moisture driven out of it in an oven at low temperature before mixing with the aluminum powder and the finished explosive must be protected from moisture. This explosive should be not be stored for very long and should probably be used up soon after production. Even the smallest amount of moisture in the AN will cause it to react with the aluminum to produce hydrogen gas. This can and has caused explosions in canisters of this type of explosive. AN-AL is more cap sensitive than AN-FO but a booster should still be used to guarantee ignition.
Now you are right to wonder about gravel as a choice of material for shrapnel. I don't know about any provenence on it's use for such a purpose but in reality I suppose you could put almost anything on top the bombs and it would become part of the blast and depending on the material or materials used, it would add to the damage caused.
tahoe27,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 4:57 pmEither way...I suppose it explodes.
By "trick" I thought it might be an old-timers tool-of-the-trade when mining. Could be a military tactic too. Or just some f-ed up thinkin' in the mind of a killer.
I suppose I usually think along the lines of a bomb being encased in something. Not a pile of gravel treated to explode...ya know?
Surely, it could be quite damaging if pulled off correctly.
(thx for the info above Trav)
traveller1st,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 5:09 pmNO probs and yes, they are very damaging.
The town where I grew up took a few hits from fertilizer bombs (as they were called) over the years.
You are right though about the incasing. The bombs here were car or van bombs so that acted as the casing. Maybe Z's thinking was that the holes in the earth would act as the casing - maybe the nutjob actually tried and was telling the truth about them being too big to dig in. Or he was putting them in barrels and that meant digging bigger and deeper holes to get them in there and hidden from view. Earth mover job that one.
tahoe27,
Subject: Re: Syar Rock Quarry - LHR Sat Mar 09, 2013 11:10 pmYes. Cops should have been on the lookout for a man matching the composite driving a large pick-up truck full of gravel
with bags of fertilizer and cans of stove oil. :suspect:
Scared Kid,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 2:13 pmtraveller1st wrote:NO probs and yes, they are very damaging.
The town where I grew up took a few hits from fertilizer bombs (as they were called) over the years.
You are right though about the incasing. The bombs here were car or van bombs so that acted as the casing. Maybe Z's thinking was that the holes in the earth would act as the casing - maybe the nutjob actually tried and was telling the truth about them being too big to dig in. Or he was putting them in barrels and that meant digging bigger and deeper holes to get them in there and hidden from view. Earth mover job that one.
McVey blew up the OK City Federal Building with a fertilizer and diesel fuel bomb. Some of those terrorists in New York tried to do the same to the World Trade Center also. It is a serious bomb.
tahoe27,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 2:51 pmSo do you guys think as little as say, a 5 gallon bucket, would do major damage to a large vehicle, or would it take a lot more--like a truckload?
smithy,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 2:56 pmT., I think five gallons worth would get someone's attention, for sure, and destroy a vehicle, yes.
My father - who was in the British Army's Royal Ordinance bomb disposal section would you believe - he said it paid better than other branches - always says if he had one pound of explosive of almost any type he'd show me something very exciting.
He never has, fortunately. I suspect it would make a family reunion more fun though.
Back in the day, we had a thread going on once before about this being the first threat of a fuel oil bomb - or of an ammonium nitrate one, perhaps.
Anyone recall that?
We found our way from there to this - a report of a helluva big bang, as I recollect.
http://en.wikipedia.org/wiki/Texas_City_disaster I'm still wondering if Zodiac-the-news-hound got some of his physics from here, or if the often-rumoured "he read it in a book" answer is correct.
(If it is, I don't know the book.)
It also makes me wonder how old the guy is - if the former is true. Ho hum.
tahoe27,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 3:01 pmVery interesting! Why do boys like to blow things up?
--I thank your father for his services. Would like to attend the reunion. :cherry:
smithy,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 3:04 pm 
We used to make bombs out of matches as kids, yes, I don't know why boys do this. A male right of passage?
If you come over sometime we'll see if we can get Granny as high as the chimney for ya.
Have I successfully derailed this thread? Apologies. Would like to know about the "read it in the book" angle though!
tahoe27,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 3:14 pmsmithy wrote: We used to make bombs out of matches as kids, yes, I don't know why boys do this. A male right of passage?
If you come over sometime we'll see if we can get Granny as high as the chimney for ya.
Have I successfully derailed this thread? Apologies. Would like to know about the "read it in the book" angle though!
I'm so there.
In regards to the book. I have considered searching online, but fear the repercussions of googling such things.
smithy,
Subject: Re: Syar Rock Quarry - LHR Mon Mar 25, 2013 3:19 pmRepercussions eh?
Like the FBI knowing who reads what books from studying library cards? (As was on the movie Seven last night, which I watched for the umpteenth time).
Well OK I'll give it a go myself, then. Might be an adventure!
Seagull,
Subject: Re: Syar Rock Quarry - LHR Tue Mar 26, 2013 1:09 amI have a copy of "The Anarchist Cookbook" though first published in 1971, the formulas for bomb making had been around for years as evidenced by the number of bombings across the nation in the '60's and '70's. This book has 61 formulas for ammonium nitrate compounds for high explosives. About half of them do not require TNT.
Bombing was big back then and Zodiac was very current in that respect. He may have been a fuddy-duddy in other respects.
smithy,
Subject: Re: Syar Rock Quarry - LHR Tue Mar 26, 2013 3:54 amSeagull, I guess I should be looking at newspaper articles rather than for books, then. I'd no idea a wave of bombing was going on during preceding times. Doh!
Perhaps the Cookbook is the one that I've heard (incorrectly) cited in the past. It sounds like the title that I recall.
glurk,
Subject: Re: Syar Rock Quarry - LHR Tue Mar 26, 2013 5:40 amI have "The Anarchist Cookbook" also. But maybe more interesting, I also have the FOIA FBI file on it as a PDF.
Download here:
http://www.filedropper.com/fbi-anarchis ... k1971-1999-glurk
smithy,
Subject: Re: Syar Rock Quarry - LHR Tue Mar 26, 2013 9:37 amObligato, glurk. Highly amusing in places, that.
I'm off to make a shaving foam bomb. I'll let you know how effective it is later. Hopefully.
Seagull,
Subject: Re: Syar Rock Quarry - LHR Tue Mar 26, 2013 10:45 amThanks for the download Glurk!
smithy,
Subject: Re: Syar Rock Quarry - LHR Mon Apr 01, 2013 3:47 amIn the same vein, I've found and downloaded the "Blasters Handbook" - which is basically DuPont's "Users Guide" to their various explosive products.
http://www.scribd.com/doc/13666411/Blasters-Handbook It's very "Ted K", with some diagrams of blasting caps and so on which vaguely remind me of his material, but overall it's much more about the professional use of marketed products than about a home-constructed ammonium nitrate and fuel oil "bomb".
I'll keep looking. I'd like to find the printed source for this information once and for all - if it's in the public domain - and if it exists, of course.
My lack of knowledge in respect to Chemistry is just about 100%, by the way. I had no notion that "One of the first rules taught in chemistry courses is don’t store oxidizers with flammables...." for instance. (It says that here. And some other interesting things:)
http://www.aristatek.com/newsletter/051 ... speak.aspx I suppose, then, that although use of an ANFO bomb "in a terrorist manner" didn't come along until after this letter from the Zodiac, that the knowledge was quite common? So I'm struggling. Still looking though.
No, nobody has knocked on the door to arrest and question me, as yet. I'll keep you posted.
Posted: Fri Mar 29, 2013 1:54 am
