History of industrial explosives

Posted on February 8, 2016 by Oleg Volk

Reading about Nobel, it seemed that dynamite and gelignite were mostly supplanted in engineering uses by ANFO, described as “safer in use and also more powerful”. I was under the impression that nitrate-based explosives were rather weak for the volume and were employed mainly for reasons of low cost and availability, not power. Where could I find ranking of various historic substances by power and brisance?

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18 Responses to History of industrial explosives

  1. Charlie Johnston says:
    February 8, 2016 at 2:15 pm

    The energy density of dynamite (stabilized nitroglycerine) is 7.5 M joules/Kg. TNT’s (trinitrotoluene) energy density stands at 4.6 M joules/Kg. ANFO has an energy density of 6.3 megajoules per kg.

    The explosive advantage is rapid energy release, so lots of other things have higher energy densities. Hard coal: 31, Kerosene: 46.3, propane: 50.3, and hydrogen has the most at 142 MJ per kg.

  2. Ray says:
    February 8, 2016 at 2:51 pm

    Aluminum powder mixed with water and ammonium nitrate will make a respectable “bang”too. The rate of detonation for all of the discussed explosives is relatively moderate when compared to RDX or PTEN. The advantage to TNT, RDX, PETN or any of the other “military” explosives, over AMFO is BULK. You can carry a 500Lb “dumb bomb” that can level a building, in a ford f-150. It takes a 5 ton truck to move its equivalent explosive power in AMFO. The rate of detonation for AMFO, being less than half that of an RDX filled 500Lb “dumb bomb” , it take considerably more of AMFO to do the same amount of damage. Something around 400Lb of RDX vs. 1500-2000lb of AMFO. That’s where the basic misconception comes from. Nitrostarch , Nitrocellulose , TNT , and Dynamite are all in the same class of explosives as AMFO , just much less bulky. P.S. The most famous (infamous?) explosives in the world today are both RDX based, C-4 and SEMTEX

  3. Tim says:
    February 8, 2016 at 3:23 pm

    I believe you can find a chart of comparative power and brissance in this book. http://dujs.dartmouth.edu/wp-content/uploads/2012/05/12s-explosive-chemistry.pdf

  4. Hugh Davis says:
    February 8, 2016 at 3:37 pm

    Try the DuPont Blasters Manual or the Dyno Nobel app for iPhone or iPad.

  5. The Neon Madman says:
    February 8, 2016 at 10:53 pm

    I’d ask Joe Huffman..

  6. Rolf says:
    February 8, 2016 at 11:16 pm

    You are looking for RE factor, at least as a starting point.

    https://en.wikipedia.org/wiki/Relative_effectiveness_factor

  7. L M Simmons says:
    February 9, 2016 at 12:17 am

    ANFO (ammonium nitrate and fuel oil) is a blasting agent, not an explosive, per se. It’s effectiveness stems from it’s low cost, ease of application and expansion characteristics. Whereas dynamites have a shattering effect, ANFO has a heaving effect. If wet conditions, you will have to use either dynamite or expensive ANFO slurries made for wet conditions. When we figure a job cost, we figure on using ANFO, but always have a “water” clause. Dyno is much more expensive to accomplish the same amount of work.

  8. Dylan Saunders says:
    February 9, 2016 at 1:47 am

    I would say that the big draws for the AN-based blasting agents are cost and convenience. ANFO, AN-based emulsions, etc., are very stable, can be stored in non-bullet-proof magazines, are very inexpensive, and can be loaded and handled very efficiently, saving money in time and wages. AN-based cartridges, such as Blastex, are not as cost efficient nor as efficient to load as info or emulsions, but still have most of these advantages. They can all be handled without risk of a headache, as well.
    As far as more powerful? That is sort of a subjective statement. What works best depends on the work to be done, and certain factors are an advantage in certain situations and a disadvantage in others. AN products are gassy, usually have a lower velocity, and cause more movement. High explosives, such as dynamite, generally have higher velocities and can cause more fragmentation with less movement depending on use.
    I still use tons of dynamite – I like the stuff. For priming is is cheaper than cast boosters, and if I want to use a bit more of it in priming to accelerate the velocity of blasting agents, I can do so. I also use it in shooting close to structures (I have shot within yards of multi-million dollar homes, utilities, etc., just recently shot 10 feet from the fiber optic line that provides communication to an entire state), shooting trenches, demolishing structures, shooting for armor, etc. More dynamite would be used today if people really chose the best product for the job they are doing, but the convenience, cost effectiveness, and simplicity of using AN-based products cause a lot of people to just use the same AN products for everything.
    For technical info, the old DuPont blaster’s handbook has been updated and replaced by a publication from the ISEE, which is kind of expensive, but has good information. For modern products, I can send you a little booklet from Dyno Nobel if you email me your address.

  9. Dylan Saunders says:
    February 9, 2016 at 2:31 am

    ANFO has a velocity of around 12,000 fps depending on the quality. Energy is 720, poured.
    Velocity of dynamite is tailored to the purpose, but ranges generally from around 20,000 to 24,000, with energy between 1,000 and 1,900.

    PETN and RDX, which are both used generally in initiation products on the commercial side, have velocities from 25,000 FPS to 27,000 FPS, and specific gravity of 1.7 to 1.76.

    So dynamite and similar high explosives are definitely not in the same class as ANFO, being more toward PETN and RDX in characteristics, but without the obvious military benefits of stability and efficiency in volume that especially RDX has.

    You also touched on density – dynamite generally has densities between 1.5 and 1.7. ANFO has a density of .82. This means that even if all other factors were the same, you still could not fit the same explosive power in the same space with ANFO. So it is not just the difference in velocity, but the difference in volume as well – and whether loading a structure to be demolished, a borehole, or munition cases, space is often a limiting factor.

    The results that are achieved using ANFO vs. dynamite are very different, and they are not in the same class at all.

  10. Mike says:
    February 9, 2016 at 6:34 am

    The main difference in the types of explosives mentions is speed of detonation, also known as brissance. Military explosives explode at a much higher rate than ANFO. The speed at which they detonate makes them much better at cutting steel and the like. ANFO is much slower, generating a “heaving” effect, which makes it extremely good at moving earth, it’s primary use. It’s also needs very exacting conditions to explode. ANFO needs to be confined like in a bore hole and requires a booster usually a small TNT charge to be detonated. Due to this fact, it is relatively safe to transport to the site of use in tanker trucks on public highways. Explosives are rated against the standard of TNT = 1 C-4= 1.34 and ANFO= .63. Nitroglycerin based explosives are extremely unstable, the main factor for their fall from use.

  12. LarryArnold says:
    February 10, 2016 at 5:06 am

    When one shops for explosives the relative power is usually the second consideration. The first is stability.

    IOW, will it go “boom” when you want it to, and not go “boom” when you don’t.

  13. R Duwe says:
    February 11, 2016 at 3:19 pm

    FWIW: The main reasons for the shift from dynamite to ANFO was price, ease of use, and safety.
    Price. Dynamite costs a lot more than ANFO.
    EASE. ANFO is a slurry, so size of bore hole is irrelevant. And it fills vertical bores in strip pits fast & easy, self tamping.
    SAFETY. cannot set off ANFO without an explosive, is immune to rifle fire. Sixty percent dynamite will detonate with 22 Short hit, any pistol ammo. The movies actually got that one right. Thus dynamite is scary to transport. ANFO , until mixed, is just fertilizer & diesel, thus not even an explosive. Shipping is cheap.

  14. Paul Koning says:
    February 12, 2016 at 2:09 pm

    My father had a wonderful small reference book, in German, “Explosivchemie” (which means just what it sounds like). It had some discussion on the subject.

    One consideration is “brisance” which I think translates to “how long does it take for the reaction to complete?” You want low brisance for propellants, high brisance for explosives meant to break things. (Same reasoning that says you break bricks with a chisel and hard hammer, not with a rubber mallet.)

    Somewhat related: I read that some explosives (the ammonium nitrate ones?) burn so quickly that they have a relatively low risk of setting ambient flammable gases on fire. That, it was claimed, was the reason for their use in mines.

    Larry’s point is crucial. Nitroglycerin disappeared (as an explosive used by itself) for that precise reason. Dynamite appeared for that reason. A lot of modern explosives are fairly hard to set of, requiring a substantial primer and confinement. Light them with a torch and all you get is a hot campfire. Sometimes you read about people cooking dinner on blocks of C-4…

  15. Hartley says:
    February 16, 2016 at 10:06 am

    The quality that most distinguishes explosives is VELOCITY – that is, how fast it burns/explodes. You want a fast explosive to break or cut things, a low-velocity explosive to move or lift stuff. C4 is relatively fast, so useful for breaking reinforced concrete or cutting steel, while ANFO is slow, good for excavating dirt and rock.

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