From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: Brisance and stuff?
Date: 18 Dec 1996 04:20:59 GMT

In article <Pine.SOL.3.91.961217154448.29757A-100000@aton.abo.fi>,
Jonas Lindholm KTF91 <jonlindh@aton.abo.fi> says:

>I'm a Chemical Engineering student (working on my Masters thesis in a 
>completely different area of Chemistry) and have read some of the stuff 
>written in this newsgroup. That has lead to some questions about 
>explosives and measurement of their "explosive force" or what you would 
>call it:
>
>1) Brisance:  I read an old book about commercial explosives (from the 
>1950's - simple and interesting process designs, really!) where brisance 
>was defined as the speed of the flamefront (nitrified cellulose had the 
>highest value = approx. 7000 m/s) whereas in this newsgroup it was 
>defined as pressure in psi (" a couple of million psi"). 
>How is this measured and what is the real definition? 

It was probably I who used detonation pressure as a  quantitative 
measure of brisance.  Originally the term was simply defined in
relation to the relative performance of an explosive in any one of
a number of empirical tests which relied to at least some extent
on unconfined pressure as measured by the compression or pulverization
of a target material.  More often "brisance" was equated with 
"shattering power," a rather subjective criterion. Comparisons were 
usually relative to TNT.

>2) What other useful definitions about explosives are used? Force, 
>pressure, safety of handling the stuff and so on?

Bore hole pressure
Sensitivity to heat, cold, impact, friction, booster
Storage life
Water resistance
Resistance to dead-pressing
Volatility
Chemical compatibility
Density
Velocity
Shaped charge effectiveness
Fume class, oxygen balance
Toxicity
Air blast
Bubble energy
Cratering
Fragmentation
Fragment velocity
Gas release
Heat of explosion
Work function

To name a few.

>3) Is there some good literature covering this on the market (Should 
>cover most of the used civil and military explosives and the synthesis 
>and characterization thereof)? Our library doesn't have that many books 
>about this. (We do have some interesting articles and books in Forensic 
>Chemistry and analysis of traces of explosives)

Urbanski, *Chemistry and Technology of Explosives* (4 vols); Mel Cook, 
*The Science of High Explosives* and *The Science of Industrial 
Explosives* to name several hundred dollars worth.  

>4) Which companies in the world are the largest producers of commercial 
>civil/military explosives?

ICI and Dyno seem to have swallowed up the biggest share of the market.

Jerry (Ico)

From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: Brisance and stuff?
Date: 20 Dec 1996 10:57:07 GMT

In article <59bh2o$o94@news-e2d.gnn.com>, Michael Fanning
<User417967@gnn.com> says:

>Moreover, an increase in density is accompanied by an increase in 
>the detonation rate of the explosive, while the shock wave 
>pressure in the detonation front varies with the square of the 
>detonation rate.  ...

Mike, I believe this quote from Meyer is not quite correct.  The 
extrapolated velocity of a given explosive remains finite as the 
density approaches zero.  The empirical relationship of pressure 
(P), velocity (V) and density (D) is something like:

V= P*(A+B*D)/(C*D^2)

where the values of the constants A, B and C depend on the explosive 
chosen.

The above relationship is based on the simpler fundamental 
relationships:

V= A+BD

and

P= CD^2

For CNHO type explosives the values of the three constants can be 
approximated from a knowledge of the the heat of explosion, average 
molecular weight of the gaseous products and the weight percent of 
gaseous products using empirical equations.

If the non-zero value of detonation velocity at zero density seems 
counterintuitive, just remember that for all practical purposes 
gaseous explosives have negligible density compared with condensed
materials but exhibit detonation velocities which are substantial 
fractions of the velocities of solid and liquid explosives.

Jerry (Ico) 

From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: ?Brissance definition?
Organization: Consulting Chemist

In article <3294D5FB.40D2@tc.umn.edu>, Karl Magdsick
<magd0005@tc.umn.edu> says:

>I know that brissance is shatering power, but is there a quantitative
>measure of brissance? What are the units of such a measurement (MPa/sec.
>perhaps)?

The two most common tests are the 200 gram bomb sand test method and 
the plate dent method.  In each case the value is unitless and is 
simply expressed as an extrapolated TNT equivalent(of depth of dent 
or amount of sand crushed respectively).  It can be argued that 
fragmentation and fragment velocity tests are also a measure of
"brisance," again as measured against TNT. The same could be said of 
shaped charge effectiveness.

In my opinion, the most logical units for brisance would be pressure
generated in the unconfined state, i,e, "detonation pressure" as opposed
to "bore hole pressure."  These are the two terms used in commercial 
explosive work to indicate brisance and the potential for useful work 
output (heave).

I might even go so far as to define a new term, "specific brisance (sb),"
which would be the measured detonation pressure divided by the square 
of the density of the explosive.  Such a value would be a rough constant 
for individual ideal explosives and would have the units of acceleration.
The value of this proposed new constant would be reasonably easily
calculable from theory for ideal materials.

Speaking from the standpoint of "sb" we would have a perspective from 
which to compare dissimilar materials such as sensitized NM, TNT and
Kinepak and they would probably turn out to be somewhat similar. 

Jerry (Ico)

From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: rec.pyrotechnics
Subject: Re: Correcting Incorrect Information
Date: 14 Jul 1995 05:00:40 GMT

In article <BILLW.95Jul12004935@puli.cisco.com>, billw@puli.cisco.com 
(William ) says:
>
>
>    [TNT: 80-160cm drop test;  Flash: 30-60 cm]
>
>    This makes one wonder is TNT safer to handle then FLASH?

Flash is much more dangerous to handle than TNT in the absence of
a blasting cap.  Cast or flake TNT is not cap-sensitive. You have
to grind it get it to shoot with a cap. I don't recommend it, but
I have often seen TNT hand ground with a ceramic mortar and 
pestle.

>I don't think there is any question of this.  since high explosives are
>inefficient in their energy releasing properties compared with
>combustion reactions.  Indeed, it may be impossible to achieve the
>desired "tone" of bang equivilent to a flash based salute with ANY
>amount of high explosive.
>
>On the other hand, the distance those fragments could travel and how
>much damage they could do is dependant on the total energy release by
>the explosion (and imparted to the fragments), which
>wouldn't necessarilly depend on the speed of the explosion.  I'd expect a
>low-explosive and high-explosive salutes releasing comparable amounts of
>energy (same sized bang?) to be capable of similar AMOUNTS of damage,
>although the exact CHARACTER of the damage might be quite different,
>especially very close to the explosion.

Inefficient? on the contrary, a high explosive will toss shrapnel
farther and faster than a low explosive. One definition of brisance
is "The ability to accelerate metal."  The "tone" of the explosion
is related to the expansion of the gas cloud after brisance has done
its work. If you want that big bang you have to raise the temperature
of the explosion by adding aluminum.  Tritonal (TNT+Al) has a much 
more impressive sound than TNT and is more powerful, but it won't
kick shrapnel as far. Even AN based explosives with as little
as 5% Al have a pretty good crack compared with "cool" explosives.

Congratulations on your posting. Most of your points were right on.
You are certainly correct in saying that HE could make a mess of a 
steel mortar.

Jerry

From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: rec.pyrotechnics
Subject: Re: Correcting Incorrect Information
Date: 14 Jul 1995 20:25:04 GMT

In article <BILLW.95Jul14001213@puli.cisco.com>, billw@puli.cisco.com 
(William ) says:
>
>    Inefficient? on the contrary, a high explosive will toss shrapnel
>    farther and faster than a low explosive. One definition of brisance
>    is "The ability to accelerate metal."
>
>Isn't brisance more like "shattering power" ?

Fragment velocity and number of fragments are measures of brisance
as are the sand crush test and the plate dent test and the lead
cylinder compression test. 

>But anyway, that's not quite what I meant.  Let's see.  An example!
>Consider a high power rifle.  A gram or so of low explosive, BURNT as a
>propellant, will send the bullet off at high velocity, and ranges of what, a
>mile or more?  Replace the LE with a HE detonation, and you get little
>pieces of gun barrel traveling in every direction, but none are going to go
>a mile...
>
>Now, from descriptions here and on PML, it seems like in a typical mortar
>accident (mortar tube "launched" a long distance), you're looking at more of
>a propellant (LE) style explosion than a HE detonation - perhaps the hole in
>the sand even helps act as a "barrel".  I'd sort of expect a true HE
>detonation to use more of its energy shattering the mortar and pulverizing
>the sand than heaving pieces a great distance.

You gun analogy is a poor one. Obviously the conservation of 
energy and momentum laws dictate that a bullet will travel faster
if the barrel doesn't rupture. If you are concerned with the 
balistics of whatever is being shot from a mortar, then LE will
launch your projectiles as fast as tensile strength will allow.
If your talking about fragment velocity, then HE will do more.
You can expect fragments of all sizes from ductile materials like
most steel. Yes, HE can toss shrapnel over a mile, but it usually
doesn't because of poor external ballistics (at least in small 
charges). A head-on detonation front can accelerate metal plate to
up around 3,000 meters/sec.

>Doesn't this end up being similar to the choices blasters make for "slow"
>explosives with lots of "heaving" power vs "fast" explosives with lots of
>shattering power ?

Most blasters actually seem to believe this old-wives tale. 20% stumping
dynamite is a very low NG material with commensurate low brisance. It
costs less than the faster materials and is generally adequate.  However
the faster powder will blow more stumps per pound.

The only area in which low velocity "heaving" materials excel is in
blasting substances one wants in large chunks, like lump coal or
granite blocks.

From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: rec.pyrotechnics
Subject: Re: Correcting Incorrect Information
Date: 14 Jul 1995 21:11:14 GMT

In article <3u669q$je0@nntpd.lkg.dec.com>, buda@star.enet.dec.com (Mark A. 
Buda) says:

>In article <BILLW.95Jul14001213@puli.cisco.com>, billw@puli.cisco.com 
>(William ) writes:
>
>>    Inefficient? on the contrary, a high explosive will toss shrapnel
>>    farther and faster than a low explosive. One definition of brisance
>>    is "The ability to accelerate metal."
>
>>Isn't brisance more like "shattering power" ?
>
>You have brought up an interesting point.  Depending on qty of HE, it is
>possible that a mortar will be in MORE SMALLER pieces, which will travel
>a shorter distance than something that would throw a large
>piece of tube a long distance.
>
>It would be interesting to study this and understand.  I can see two sides
>to what could happen.

If the mortar is made of brittle cast iron or ceramic, you might 
luck out and get tiny frag, but with steel and other ductile materials
I wouldn't depend on it. I can still (after 25 years) remember the sound
of huge fragments from a 500 lb bomb hurtling through the forest in a
test with a 90% buried unit. 

>A lot depends on type/qty of HE.  Anyone have some real life reference
>material on this subject?  There is no doubt that certain HE (TNT/Al)
>would have less effect on gun (less energy) and be safer than other HE.

There are published data on the number of fragments produced by 
some explosives fired in a couple of projectile cases. For instance
80/20 TNT/Al yields 616 and 485 pieces respectively in 90 mm and
3" projectiles. The corresponding values for TNT are 703 and 514.

Frag velocity is measured for charges in in 10" long by 3" O.D. by 
2" I.D.  1020 steel cylinders. At 9 feet the 80/20 mix gives 2460
ft/sec compared to 2600 for TNT.

Faster explosives like cyclotol can produce twice as many fragments 
as TNT.

Jerry

Subject: Re: What is the most powerful manmade explosive other than nuclear?
From: glhurst@onr.com (Gerald L. Hurst) 
Date: Apr 11 1996
Newsgroups: sci.physics,alt.engr.explosives

In article <4kj35d$eb6@frazier.uoknor.edu>, major@rodent.ecn.uoknor.edu
(Dan Major) says:

>So is Vdet an indicator of brisance, the higher the Vdet the greater the
>brisance?

If you read my response to Bill in which I describe the beryllium 
rod thought experiment, you can see that "vdet" can be more or less 
be independent of brisance, at least in theory. In practice, when 
you are dealing with real CHNO explosives of an ideal nature you 
can use the rough approximations for detonation pressure (P = 
brisance) and Velocity (V) that say that both P and V are proportional 
to the square root of the energy at a given density.

V, however, increases much more slowly than P as the pressure is
increased. The pressure rises as the square of the density,
i.e., is very sensitive to changes in density. Velocity, on the 
other hand, climbs roughly in proportion to (1+1.3*density), i.e.,
relatively slowly with respect to density.

rec.pyrotechnics omitted.

Jerry (Ico)     

From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: to DR on 10,000
Date: Sat, 04 Dec 1999 08:35:56 GMT

It is a common misconception that higher brisance is necessarily
accompanied by lower heaving ability.   It is true that the addition
of aluminum to an ideal explosive will increase heave and decrease
brisance somewhat because the metal may not participate in the
detonation per se but merely furnish added energy by after-burning.

In general though, brisant explosives tend to heave at least as well
as their slower cousins.

Blasting agents are not necessarily less brisant than high explosives.
In each case the brisance is determined by the energy and density
of the material, assuming it is shot in a sufficiently large diameter.
Because high brisance is not always necessary in blasting operations,
the formulations may include heterogeneous fuels and oxidizers which
lower velocity but offer cost savings.

Jerry (Ico)

DR <rodmon@DELETETHISattcanada.net> wrote in message
news:hE024.5802$j%2.557@cabot.ops.attcanada.net...

> There is a bit of both in the powder,  brissance and heave,... besides if
> you knew as much as you claim to know about explosives and blasting agents
> you would know that blasting agents can be formulated to behave in a highly
> ideal fashion with the right know how ( high brisance and very little
> heave...). The quantities that I am used to see are way too big for a
> magazine, instead it requires a huge warehouse...I think that you have
> suddenly realized that you are outgunned and you know it...

From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: to DR on 10,000
Date: Mon, 06 Dec 1999 10:11:50 GMT

That (excerpted bit) is indeed precisely what you said, and
it is incorrect.  Blasting agents can, of course, be formulated
to behave ideally, but such ideal formulations will not produce
"very little heave."  This is one of the old wives' tales of
explosives.  It stems from a misinterpretation of the fact
that slow explosives are superior in breaking coal into nice
large chunks without shattering it.  The tale was abetted by
the explosives industry in order to sell cheaper formulations
for such work as stumping, where little brisance is required.
In practice, however, high velocity charges are actually
superior for stump removal and excavation.

The argument about the partition of energy is lame.  Under
the best of circumstances only a small percentage of energy
goes into shock wave formation and that small fraction of the
total energy is not all lost from the heaving operation.
"Partitioning" looks good on paper but you will not see it
reflected in the actual diminution of heave in real blasting.

The ability to heave is measured by the ballistic mortar
(pendulum).  If you compare plate dent or sand crush values
(brisance) with mortar results, you will see that, in general,
ideal explosives (or blasting agents) with good brisance
exhibit good heave.

You can certainly generate a lot of heave with little brisance
simply by introducing macroscopic fuel-oxidizer heterogeneity
into an inherently energetic mix.  It was for the purpose of
illustrating this principle that I brought up the subject of
aluminum.  It is quite simple:  the factors that lead to high
brisance must necessarily produce substantial heave, but an
explosive material can have good heave without significant
brisance.

Jerry (Ico)

DR <rodmon@DELETETHISattcanada.net> wrote in message
news:7k924.5878$j%2.529@cabot.ops.attcanada.net...
>
> Gerald L. Hurst wrote in message ...
> >It is a common misconception that higher brisance is necessarily
> >accompanied by lower heaving ability.   It is true that the addition
> >of aluminum to an ideal explosive will increase heave and decrease
> >brisance somewhat because the metal may not participate in the
> >detonation per se but merely furnish added energy by after-burning.
>
>
> Good, good... but who said anything about adding aluminum? That willl no
> doubt increase the heave...but that is not what I said, this is what I said
> "...if you knew as much as you claim to know about explosives and blasting
> agents you would know that blasting agents can be formulated to behave in a
> highly ideal fashion with the right know how ( {produce} high brisance and
> very little heave...)." That means exactly what I said. I was thinking of
> explosive emulsions and of crystal growth modifiers for crystalline
> particulation. I was thinking of the same particulation technique used for
> adding AN crystals to Ammonia dynamites and 'Ammonia' gelatin dynamites. Who
> said anything about adding aluminum? Actually, adding increasing amounts of
> aluminum reduces the detonation velocity's slopes in the curves (straight
> lines) for VOD (ordinate) as a function of density (abcissa). That would
> cause the opposite effect of what I posted, so let me ask you: Who mentioned
> adding aluminum?
>
> >
> >In general though, brisant explosives tend to heave at least as well
> >as their slower cousins.
>
> Not really, the more ideal the reaction is the least amount of unreacted
> product is left when the detonation waves have passed by. When you want both
> fragmentation and TO THROW ROCK FARTHER you don't think of brisant
> explosives.
> >
> >Blasting agents are not necessarily less brisant than high explosives.
> >In each case the brisance is determined by the energy and density
> >of the material, assuming it is shot in a sufficiently large diameter.
>
> Generally speaking they are less brisant because the energy is partitioned
> between shock and heave. Quoting from page #238 from Wang Xuyuang's Emulsion
> Explosives "Table 6:17 Brisance values of several explosives
> TNT 1.0gr./cm3 ----16-17mm; TNT 1.2gr./cm3 ----18.8mm; ANWAX
> 0.9gr./cm3---8-9mm; EL series emulsion explosive 1.05-1.30gr/cm3---16-20mm
>
> ANWAX is Ammonium Nitrate + Asphalt wax explosive. Look at the difference in
> brisance of ANWAX when compared to the emulsion or the TNT.
>
> However if we are always considering the case of very large diameter shots,
> then yes they will tend to behave in an ideal manner. On the other hand,
> explosive emulsions' brisance is least affected by charge diameter or
> confinement among heterogeneous products.
>
> >Because high brisance is not always necessary in blasting operations,
> >the formulations may include heterogeneous fuels and oxidizers which
> >lower velocity but offer cost savings.
>
> Lower velocity is not necessarily always the case, when you consider
> explosive emulsions.
>
> >Jerry (Ico)
> >
> <snip>

From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: to DR on 10,000 (Partition of the energy)
Date: Mon, 13 Dec 1999 05:37:20 GMT

I believe I now understand where your reasoning goes astray.

With respect to an earlier post invoking an ICI patent disclosure, you
have an excellent opportunity to learn that seeing something in print
(even in a patent) does not make it so.  Slowing an explosive down
with a "slow-burning fuel" will not make it heave better.  When I wrote
that  the inverse relationship between shock and heave was a
common misconception, I did not intend to exclude the explosives
industry.  It was, after all, they who originated the myth and to some
extent it is they who continue to perpetuate it.

Now let's look at your current post.  Where does the energy from the
CJ zone go when it ceases to be classified as "shock"?  It becomes
simple heat in a highly compressed gas, which is now available to be
converted into mechanical energy, in other words, "heave."  The only
free energy (Gibbs free energy that is) actually lost from the near
adiabatic reaction in the CJ zone is that transferred directly to the
rock as transmitted shock.  That relatively small amount of energy IS
lost in heating the rock except insofar as it does useful work in
shattering it.

Remember the law of conservation of energy.

Your idea that the expanding gases are lost as a result of blowing
through the cracks should be reserved for low-velocity explosives.
With black powder and other slow explosives, pressure blow-by
is much more a problem than with high explosives.  When shooting
in hard rock you have to break it before you can heave it.  The
common problem of shotgunning is often encountered with slow
explosives but rarely with high-velocity explosives.  When rock is
broken by tension created by shock waves, the cracks are minute
as the highly compressed gases push against the fragments.
What happens later when the rocks fragments have a significant
distance between them is the same for high and low explosives
because, in either case, the pressures are then relatively low.

If you will now take the 97% you subtracted and add it back to the
heave category (minus the conversion loss dictated by
thermodynamics), you will have a better approach to reality.

Jerry (Ico)



DR <rodmon@DELETETHISattcanada.net> wrote in message
news:DZj34.6678$fy1.729@tundra.ops.attcanada.net...

> The point I am still trying to get across is that AN can be formulated to
> react 97% of its energy in C-J state. This leaves as little as 3% for
> additional heave released for rock throwing. AN is the oxidizer in the
> explosive emulsion described in my post to Gerald L. Hurst. Regarding
> his/your claims about heave in ideal explosives and military explosives in
> general...Once the rock yields under the pressure pulse, the hot gases
> escape through the cracks without necessarily moving the rocks. You could
> have everything broken up but no significant movement, leaving a standing
> monument of broken rock.

From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: to DR on 10,000 (Partition of the energy)
Date: Tue, 14 Dec 1999 09:00:12 GMT

Because nothing improves heave more than sheer raw energy
and aluminum certainly adds that.  If it were not so expensive,
aluminum would be added to more than than just the toe.  I
covered this topic in my post of 12/6 and in my original message
which began:

"It is a common misconception that higher brisance is necessarily
accompanied by lower heaving ability.  It is true that the addition
of aluminum to an ideal explosive will increase heave and decrease
brisance somewhat because the metal may not participate in the
detonation per se but merely furnish added energy by after-burning.
In general though, brisant explosives tend to heave at least as well
as their slower cousins."

Aluminum slows detonation velocity down only a wee bit but it
adds very significantly to the total energy output.  In some cases,
the aluminum actually speeds up the detonation.  The explosive
"Moleculite" is a good example.

It appears that the aluminum topic, which you originally labeled as
a "red herring," does indeed have some relevance :)

The first generalization is that, other things being equal, more energy
means better heave.

The second generalization is that on an equal energy basis, fast
explosives usually heave better than slow ones.

Certain reductio ad absurdum arguments and borderline cases
excepted.

Jerry (Ico)



DR <rodmon@DELETETHISattcanada.net> wrote in message
news:Fbf54.8924$j%2.661@cabot.ops.attcanada.net...

> Gerald L. Hurst wrote in message ...
> >I believe I now understand where your reasoning goes astray.
> >
> >With respect to an earlier post invoking an ICI patent disclosure, you
> >have an excellent opportunity to learn that seeing something in print
> >(even in a patent) does not make it so.  Slowing an explosive down
> >with a "slow-burning fuel" will not make it heave better.
>
> Thank you, but why is then Aluminun added to the bottom of the borehole for
> "toe" break up and moving it?

From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: to DR on 10,000
Date: Mon, 13 Dec 1999 10:08:53 GMT

It ain't necessarily so.

As per my last post, you are confusing the concept of the high-pressure
CJ zone with "lost" shock energy, that is, energy not available for
heaving work.   The relevant shock for energy loss considerations is
only that which is transmitted into the target and which does not
result in fracturing.  This relatively minor amount of energy is lost
in the sense that it degenerates into heat in the rock.

The shock front energy in the explosive itself remains viable for doing
work after the detonation head has passed.   The CJ zone is simply
part of the mechanism by which latent chemical energy is transformed
into heat and work in the particular case of detonation.  This
mechanism has very little bearing on the thermodynamic outcome
of the reaction in terms of how much work is done except to the
extent that a faster reaction allows more work to be done against the
rock instead of against the atmosphere by blow-by.

In the end, high explosives generally heave better than slower
explosives for two reasons:

1.  They fragment the rock better so the explosive doesn't have to
move the whole mountain.

2.  They do much of their mechanical work in converting pressure to
motion before the rock has moved far enough to allow much blow-by.

The inherent abilities of high and low explosives (of the same gross
composition) to do work  are about equal under ideal conditions such
as in a ballistic mortar, where fragmentation is not required and there
is no premature venting.  In real life, conditions are rarely ideal, and the
rock needs to be broken to be moved.  Also in real life,  rock is not
a well-fitted piston so blow-by is a problem -- the slower the
explosive the bigger the problem.

High explosives generally react quickly enough to avoid excessive
venting and their high initial pressures assure that the rock will
break and become movable.  It is true that they use some of their
energy (a very small proportion) in transmitting a shock wave to the
rock but this loss is more than offset by the superior fragmentation
and minimization of blow-by.

Your numbers are just that -- numbers.  This is what is often referred
to as techno-babble and has no relevance to the physical phenomena
you are attempting to describe.  The numbers are only useful after
you learn how to apply them in the paradigm.

Now, for those of you who are still buying the powder company
malarkey about slow explosives being better than faster ones for
certain applications, I can only say, "Yeah, once in a blue moon."
If you are cutting granite blocks, you might be better off using
black powder since the art is well developed.  However, for
most applications, if you can do it with slow powder, you can
do it just as well, probably better, with fast powder.  You just have to
learn to adapt your bore hole diameter and spacing.  You can
always get LESS pressure out of a fast explosive but you can't get
MORE pressure out of a slow explosive.

Jerry (Ico)

DR <rodmon@DELETETHISattcanada.net> wrote in message
news:G6X24.6530$j%2.618@cabot.ops.attcanada.net...
>
>
> --
> "The way of the fool is right in his own eye..." Proverbs 12:15; "There is a
> way which seemeth right unto a man [or woman], but the end thereof [are] the
> ways of death." Proverbs 14:12
> http://freeyellow.com/members/tips4you/index.html
> Gerald L. Hurst wrote in message ...
> ><SNIP>
> >The argument about the partition of energy is lame.  Under
> >the best of circumstances only a small percentage of energy
> >goes into shock wave formation and that small fraction of the
> >total energy is not all lost from the heaving operation.
> >"Partitioning" looks good on paper but you will not see it
> >reflected in the actual diminution of heave in real blasting.
>
> Lets use the example of the perrformance of a well known blasting agent
> ANFO. We will also compare it to that of an explosive emulsion which by the
> way is a heterogeneous mix of fuel and oxidizer. I will attempt to refute
> your claim that only a small percentage of energy goes into shock wave
> formation. This is a repost from another thread in which I refuted something
> else with facts not myths like your own.
>
>  "Lets look at the experimental detonation velocity and compare it to the
> theoretical detonation velocity . Data extracted from Table 6.12 page 230 of
> "Emulsion Explosives" Prof Wang Xuguang
>
> ANFO @ 0.8 g/cc experimentally clicks at 2900 m/s yet it should
> theoretically detonate @ 4896.4 m/s ; hence reaction rate 0.35 (using the
> 2nd power of the ratio of experimental to theoretical VODs). And I ask you,
> is 35% indicative of a small percentage? Nope! But the precariousness of the
> understanding of AN's ambiguous behaviour is that depending on confinement
> and/or charge diameter AN would approach more ideal behaviour! For example:
> ANFO would reach 4750 m/s in a 12 1/4 inch borehole."  Do the math and you
> will find 66.3% of the energy is released to support the shock wave. Is that
> a small percentage of the energy going to the shock wave?"
>
> In contrast, and Emulsion Explosive @ 1.10 g/cc experimentally records 5750
> m/s pretty close to theoretical detonation @ 5834.2 m/s ; hence reaction
> rate 0.97 (using the 2nd power of the ratio of experimental to theoretical
> VODs)." Is 97% a small percentage of the energy going to support the shock
> wave?
>
>
>
>
> >The ability to heave is measured by the ballistic mortar
> >(pendulum).  If you compare plate dent or sand crush values
> >(brisance) with mortar results, you will see that, in general,
> >ideal explosives (or blasting agents) with good brisance
> >exhibit good heave.
> >
> >You can certainly generate a lot of heave with little brisance
> >simply by introducing macroscopic fuel-oxidizer heterogeneity
> >into an inherently energetic mix.  It was for the purpose of
> >illustrating this principle that I brought up the subject of
> >aluminum.  It is quite simple:  the factors that lead to high
> >brisance must necessarily produce substantial heave, but an
> >explosive material can have good heave without significant
> >brisance.
> >
> >Jerry (Ico)
>
> Look at the figures above for the square of the ratio of experimental VOD
> over theretical VOD for an explosive emulsion. The  97% of the energy going
> to support the shock wave, not bad for a heterogeneous fuel oxidizer mix,
> and that is what I was going over when you jumped in with your Aluminum red
> herring, don't you think?