removed. The first round (M1) was placed on its side
on top of a metal plate on the surface of the snow (Fig.
3). The C4 was laid across the top of the round and an
M7 blasting cap attached. The mortar round was deto-
nated with a timer by the EOD team at about 1100. The
weather was clear, with a light breeze from the south-
east.
The detonation produced a cloud of black soot,
because of the presence of TNT in the round, that set-
tled on the snow surface and was quite visible, easily
delineating the areas where residues were deposited.
We collected five surface snow samples that ranged in
distance from the crater from 4 to 28 m, and which
ranged in area sampled from 1.16 to 9.29 m2 (Fig. 4a).
The five snow samples from this first detonation were
Figure 3. An 81-mm mortar round placed on its side
collected from 1100 to 1130 and were labeled M1-S1
on the surface of the snow.
through M1-S5.
Two more rounds (M2 and M3) were detonated as
which is composed of 84.2% nitrocellulose, 1.0% diphe-
described above, except that they were placed directly
nylamine, 4.9% diethylphthalate, and 9.9% dinitrotol-
on the snow surface without a metal plate. Sampling
uene. An ignition cartridge composed of 57.75% nitro-
was conducted in a similar fashion. Four surface snow
cellulose, 40.0% NG, 1.5% potassium nitrate, and
samples were collected from each of these areas where
0.75% diphenylamine is also present in this round.
surface residues were visible. The approximate areas
of deposition from each detonation are shown in Fig-
Mortar round detonation and
ures 4b and c.
sample collection, Camp Ethan Allen
Surface snow samples were collected using an
Three locations were selected at a snow-covered
unpainted aluminum snow shovel. The depth sampled
impact range at Camp Ethan Allan. The 81-mm mortar
was kept as small as possible to minimize the volume
rounds were unpacked and the propellant bags were
of snowmelt produced. Depths sampled depended on
Detonation Crater
Mortar and
C-4 Orientation
Visible Plume = 158 m2
Visible Plume Sampled = 24.4 m2
m
East
6
3
0
S4
S3
S2
S1
S5
3
6
3
0
3
6
9
12
15
18
21
24
27
30 m
West
a. First detonation.
Figure 4. Residue deposition and surface snow samples collected for 81-mm mortar round deto-
nations at Camp Ethan Allen.
3
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