Detonation of ANFO without a secondary explosive booster charge

[November 5]

Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?

For example:

ANFO main charge
|------------------------------------------------------|
| ANFO self-booster charge |
| |
|------------------------------------| |
= Black powder | |
|----------------------------------- | |
| |
| |
|------------------------------------------------------|


The black powder core, much like a firecracker, is set off first. It
has a strong casing so that rupture of it will produce a step-front
shock wave.

The ANFO self-booster charge contains a coarse granular mixture of AN
+ diesel, or perhaps low density wood chips (e.g. balsa). The porosity
of the ANFO grains results in adiabatic compression of the empty
spaces within it, causing local hotspots. A small quantity of fine
magnesium or aluminium powder may be added to the self-booster charge
to facilitate decomposition of the AN.

Once the self-booster charge detonates, it too ruptures the vessel it
is in and produces a much stronger, step-front shock wave that will
hopefully be a self-sustaining detonation wave in the bulk ANFO. For
higher energy densities, a fine powdered mixture of ANFO can be used
with consequently better packing than coarse grains.

N5

[Me]

In article

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?
ANFO main charge
|------------------------------------------------------|
| ANFO self-booster charge |
| |
|------------------------------------| |
= Black powder | |
|----------------------------------- | |
| |
| |
|------------------------------------------------------|
The black powder core, much like a firecracker, is set off first. It
has a strong casing so that rupture of it will produce a step-front
shock wave.
The ANFO self-booster charge contains a coarse granular mixture of AN
+ diesel, or perhaps low density wood chips (e.g. balsa). The porosity
of the ANFO grains results in adiabatic compression of the empty
spaces within it, causing local hotspots. A small quantity of fine
magnesium or aluminium powder may be added to the self-booster charge
to facilitate decomposition of the AN.
Once the self-booster charge detonates, it too ruptures the vessel it
is in and produces a much stronger, step-front shock wave that will
hopefully be a self-sustaining detonation wave in the bulk ANFO. For
higher energy densities, a fine powdered mixture of ANFO can be used
with consequently better packing than coarse grains.
N5

No..... Not enough Velocity in the Shockwave... BP is way to slow....

Me one who knew this when he was 12 years old.....

[November 5]

Post by Me
In article

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?
ANFO main charge
|------------------------------------------------------|
| ANFO self-booster charge |
| |
|------------------------------------| |
= Black powder | |
|----------------------------------- | |
| |
| |
|------------------------------------------------------|
The black powder core, much like a firecracker, is set off first. It
has a strong casing so that rupture of it will produce a step-front
shock wave.
The ANFO self-booster charge contains a coarse granular mixture of AN
+ diesel, or perhaps low density wood chips (e.g. balsa). The porosity
of the ANFO grains results in adiabatic compression of the empty
spaces within it, causing local hotspots. A small quantity of fine
magnesium or aluminium powder may be added to the self-booster charge
to facilitate decomposition of the AN.
Once the self-booster charge detonates, it too ruptures the vessel it
is in and produces a much stronger, step-front shock wave that will
hopefully be a self-sustaining detonation wave in the bulk ANFO. For
higher energy densities, a fine powdered mixture of ANFO can be used
with consequently better packing than coarse grains.
N5

No..... Not enough Velocity in the Shockwave... BP is way to slow....
Me one who knew this when he was 12 years old.....

Velocity is only applicable if the initiating explosive was
unconfined; then the initiating shock velocity will be equivalent to
the shock velocity of the iniitating explosive. When you confine the
initiating explosive in a ~brittle container, then fracture of the
container will present a step-front shock to the surrounding ANFO. The
velocity of this step front shock will be partly determined by the
pressure behind it (thus determined by container rupture strength) and
the shock-propagation properties of ANFO.

Ultimately the whole purpose of the initiating explosive is to produce
a shock within the ANFO of enough strength that it can cause adiabatic
heating of sufficient intensity to initiate more ANFO. A strong shock
can be produced by an initiating explosive with a fast detonation
velocity, or confinement of a low order explosive/deflagrant.

N5

[F Murtz]

Post by November 5

Post by Me
In article

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?
ANFO main charge
|------------------------------------------------------|
| ANFO self-booster charge |
| |
|------------------------------------| |
= Black powder | |
|----------------------------------- | |
| |
| |
|------------------------------------------------------|
The black powder core, much like a firecracker, is set off first. It
has a strong casing so that rupture of it will produce a step-front
shock wave.
The ANFO self-booster charge contains a coarse granular mixture of AN
+ diesel, or perhaps low density wood chips (e.g. balsa). The porosity
of the ANFO grains results in adiabatic compression of the empty
spaces within it, causing local hotspots. A small quantity of fine
magnesium or aluminium powder may be added to the self-booster charge
to facilitate decomposition of the AN.
Once the self-booster charge detonates, it too ruptures the vessel it
is in and produces a much stronger, step-front shock wave that will
hopefully be a self-sustaining detonation wave in the bulk ANFO. For
higher energy densities, a fine powdered mixture of ANFO can be used
with consequently better packing than coarse grains.
N5

No..... Not enough Velocity in the Shockwave... BP is way to slow....
Me one who knew this when he was 12 years old.....

Velocity is only applicable if the initiating explosive was
unconfined; then the initiating shock velocity will be equivalent to
the shock velocity of the iniitating explosive. When you confine the
initiating explosive in a ~brittle container, then fracture of the
container will present a step-front shock to the surrounding ANFO. The
velocity of this step front shock will be partly determined by the
pressure behind it (thus determined by container rupture strength) and
the shock-propagation properties of ANFO.
Ultimately the whole purpose of the initiating explosive is to produce
a shock within the ANFO of enough strength that it can cause adiabatic
heating of sufficient intensity to initiate more ANFO. A strong shock
can be produced by an initiating explosive with a fast detonation
velocity, or confinement of a low order explosive/deflagrant.
N5

I might be inclined to try a bundle of short bits of det cord wrapped
round a detonator,(might set ANFO off)

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[F Murtz]

Post by F Murtz

Post by November 5

Post by Me
In article

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?
ANFO main charge
|------------------------------------------------------|
| ANFO self-booster charge |
| |
|------------------------------------| |
= Black powder | |
|----------------------------------- | |
| |
| |
|------------------------------------------------------|
The black powder core, much like a firecracker, is set off first. It
has a strong casing so that rupture of it will produce a step-front
shock wave.
The ANFO self-booster charge contains a coarse granular mixture of AN
+ diesel, or perhaps low density wood chips (e.g. balsa). The porosity
of the ANFO grains results in adiabatic compression of the empty
spaces within it, causing local hotspots. A small quantity of fine
magnesium or aluminium powder may be added to the self-booster charge
to facilitate decomposition of the AN.
Once the self-booster charge detonates, it too ruptures the vessel it
is in and produces a much stronger, step-front shock wave that will
hopefully be a self-sustaining detonation wave in the bulk ANFO. For
higher energy densities, a fine powdered mixture of ANFO can be used
with consequently better packing than coarse grains.
N5

No..... Not enough Velocity in the Shockwave... BP is way to slow....
Me one who knew this when he was 12 years old.....

Velocity is only applicable if the initiating explosive was
unconfined; then the initiating shock velocity will be equivalent to
the shock velocity of the iniitating explosive. When you confine the
initiating explosive in a ~brittle container, then fracture of the
container will present a step-front shock to the surrounding ANFO. The
velocity of this step front shock will be partly determined by the
pressure behind it (thus determined by container rupture strength) and
the shock-propagation properties of ANFO.
Ultimately the whole purpose of the initiating explosive is to produce
a shock within the ANFO of enough strength that it can cause adiabatic
heating of sufficient intensity to initiate more ANFO. A strong shock
can be produced by an initiating explosive with a fast detonation
velocity, or confinement of a low order explosive/deflagrant.
N5

I might be inclined to try a bundle of short bits of det cord wrapped
round a detonator,(might set ANFO off)
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OOPS ancient post.

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[Bill]

Post by F Murtz

Post by F Murtz
I might be inclined to try a bundle of short bits of det cord wrapped
round a detonator,(might set ANFO off)
---
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protection is active.
http://www.avast.com

OOPS ancient post.

Ancient? Positively antique!!! I've not seen any activity here for
absolutely ages.

[Me]

Post by Bill

Post by F Murtz

Post by F Murtz
I might be inclined to try a bundle of short bits of det cord wrapped
round a detonator,(might set ANFO off)
---
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protection is active.
http://www.avast.com

OOPS ancient post.

Ancient? Positively antique!!! I've not seen any activity here for
absolutely ages.

There is a reason for that.... Few want to get on the NSA's Domestic
Terrorist WatchList....

and NO, very few Low Order Energetics will, even if confined, produce a
Big enough Shockwave, to overcome the Entropy Knee, of an reasonable
load of ANFO.... and Good Powderman knows this, even without doing the
Math..... Duh.....

[b***@gmail.com]

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?
ANFO main charge
|------------------------------------------------------|
|      ANFO self-booster charge          |
|                                                      |
|------------------------------------|                 |
=         Black powder      |                 |
|----------------------------------- |                 |
|                                                      |
|                                                      |
|------------------------------------------------------|
The black powder core, much like a firecracker, is set off first. It
has a strong casing so that rupture of it will produce a step-front
shock wave.
The ANFO self-booster charge contains a coarse granular mixture of AN
+ diesel, or perhaps low density wood chips (e.g. balsa). The porosity
of the ANFO grains results in adiabatic compression of the empty
spaces within it, causing local hotspots. A small quantity of fine
magnesium or aluminium powder may be added to the self-booster charge
to facilitate decomposition of the AN.
Once the self-booster charge detonates, it too ruptures the vessel it
is in and produces a much stronger, step-front shock wave that will
hopefully be a self-sustaining detonation wave in the bulk ANFO. For
higher energy densities, a fine powdered mixture of ANFO can be used
with consequently better packing than coarse grains.
N5

10 grams or more of a conventional 7/3 potassium perchlorate/dark
german aluminum flash powder mix will initiate a 95/5 mix of ammonium
nitrate/dark german aluminum mix.This can be used to initiate a 92/8
ammonium nitrate/fuel oil anfo mix.

[Anon Emous]

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?

Sure. Bad luck works.

EXPLOSION OF A DRILL STEEL SUBJECT TO HIGH TEMPERATURE
Significant Incident Reports No: 19

Subject: EXPLOSION OF A DRILL STEEL SUBJECT TO HIGH TEMPERATURE

INCIDENT
A boilermaker was killed when a drill steel which he was welding to a
front end loader
bucket exploded. A length of discarded drill steel (50 mm diameter)
was tack welded at
one end to the bucket, and the deceased was heating the steel with an
oxy-acetylene
torch to bend the steel to conform to the bucket shape before further
arc welding. The
purpose of the drill steel was to act as a wear component, in lieu of
hard facing.

There was an explosion and the deceased was struck by shattered pieces
of the drill
steel.

CAUSE
The explosion apparently resulted from a build-up of temperature and
pressure which
detonated explosive material contained in the hollow core of the drill
steel.

A length of drill steel had previously been welded to the other side
of the loader bucket
in a similar manner, and the first 150 mm of the core was blocked with
tightly packed
material, which subsequent analysis showed to be ammonium nitrate. It
is probable that
the length which exploded was cut from the same length of steel as
that which was
already welded in place. The amount of explosive material in the core
of the rod is a
matter for speculation, but the steel has been disintegrated for a
length almost a metre
and it is therefore likely to have contained explosive along much of
its length. Only a
very small amount of explosive is required to present a critical
hazard in such
circumstances.

COMMENTS AND PREVENTATIVE ACTION
Drill steel (hollow core) which has been in use must be checked before
discard or
before it is subjected to any process of cutting, heating or
hammering, to ensure that it
has no blockage in the core, as that blockage may consist of, or
contain explosive
material.

If blocked drill steel is to be cleaned out for salvage or re-use,
then full precautions
must be taken in devising methods to do so. Application of heat,
impact, friction or
undue pressure may cause any explosive remnants to detonate. If
mechanical means
are resorted to then the process must be done by remote control with
total protection of
personnel.

Apart from the hazard potential of explosive remnants in the core,
care should be
exercised in the re-use of any discarded percussion drill steel, as it
becomes embrittled
in service. It should never be used for holding staging and securing
safety lines, nor in
any application where its failure may create a hazard.

Discarded drill steel should never be used to make scaling bars.
http://www.dme.wa.gov.au/mod/publications/sir/explosio.html 23-Apr-97

J M Torlach
STATE MINING ENGINEER. Australia February 1991

[Me]

In article

Post by Anon Emous

Post by November 5
Can ANFO be set off without a booster charge using low order
explosives (e.g powdered KNO3/Sugar or black powder) by confining the
low order explosive and a portion of the ANFO, to act as a self-
booster?

Sure. Bad luck works.
EXPLOSION OF A DRILL STEEL SUBJECT TO HIGH TEMPERATURE
Significant Incident Reports No: 19
Subject: EXPLOSION OF A DRILL STEEL SUBJECT TO HIGH TEMPERATURE
I

Exactly, this illustrates one of the few qualities of ANFO, that need to
be understood, when using it out in the field. High Temps (above 1500F)
can cause ANFO to detonate, as well as Higher Temps in the 2000F range
can cause straight AN to detonate. (Think Texas City Disaster) BP just
doesn't have the Combustion Temps to trigger detonation in ANFO, let
alone straight AN. Even if it is contained, the Shock Velocity and
Combustion Temps, do not rise to Energy level, that is required to
exceed the Entropy Knee for these materials, to reach Detonation. That
is why even most Primary Explosives, (think Blasting Caps) require
Booster Charges for reliable detonation of ANFO, and straight AN is even
harder to deal with, as it doesn't have a Fuel to oxidize.

Me just an Oldtime Powderman.....