follows is the PowerPoint presentation formatted as a scrolling
Demining Part 8: AP mine blast
presentation shows you what the detonation of a large anti-personnel
mine can be like, and also how it can impact on a kneeling deminer
who sets it off accidentally. Most accidents in HD occur while
the Victim is trying to unearth the device in a kneeling position.
follows is a series of stop-motion photographs of a test carried
out in Mozambique. The test was conducted by Dieter Guelle and
I was present as advisor. I would not have tested two PPE ensembles
against a single mine, but the result was probably unaffected
by the presence of the second dummy.
had made articulated dummies and dressed them in the PPE being
considered. If you study the pictures and look beyond the dust,
you will see that one of the dummies "stands" upright
during the blast. Its visor is torn away and then lands back
on the dummy's face. It is common for visors to be torn
away by the blast front, but at 60cm from the seat of the explosion
the fragments have overtaken the blast front - so they strike
the visor just before it is torn away. You can see trace lines
of the fragments in the second slide, before the dummies are
lifted upright by the blast front. The dummies then collapse.
the sequence progresses you can see a pall of smoke from unburned
TNT. Then you see dust on the ground being lifted like a mist
and drifting towards the seat of the explosion. This is because,
as the high explosive expands (it is effectively a small solid
trying to turn "instantly" into a large volume of
gas), there is "low pressure" behind the blast front
(sometimes easier to comprehend when inaccurately called a "partial
vacuum") which sucks air and dust from the surrounding
mine used was a GYATA-64 containing 300g of TNT. This was the largest threat mine in
the area, and is also the largest AP blast mine found. A No.8
detonator was pressed into its detonator-well with a few grams
of industrial grade Plastic Explosive to ensure a tight fit.
The detonator was then fired electronically from a safe distance.
people are surprised to hear that all the evidence from real
accidents suggests that the victims would have survived without
serious injury, except perhaps to their hands. A temporary hearing
loss would be expected (with a small permanent loss that the
victim would probably be unaware of), and the victims would
have had dust in their eyes. That dust would have been drawn
in behind the blast front and so not moving at damaging
entire sequence took under two seconds. The day was hot and
with no obvious wind, so when the dust drifted to the left it
was not being dragged by a high wind. Notice that the "victims"
stood up far more quickly than they collapsed and that they
were not thrown significantly back from the blast. This reflects the way that a deminer moves in real accidents very well.
thanks to Dieter Guelle.