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ERDC/CRREL TR-02-1
specialist of the absence of metallic debris underneath the surface soil must be
made with the help of a portable metal detector.
Once site clearance has been granted, several safety precautions still must be
observed, because highly contaminated soils can propagate a detonation. The
United States has developed a sensitivity testing protocol for determining whe-
ther soils contaminated with explosive waste are likely to initiate and propagate,
and, if so, how to best handle them. Such sensitivity testing protocol involves
many tests; including impact tests, friction and shock gap tests and the deflagra-
tion-to-detonation test (capable of measuring the shock of an explosive reaction).
The drawback of this protocol is that these tests require relatively large volumes
of soil to be excavated and shipped to specially qualified laboratories, often at
great expense. In addition, shipping of soils containing reactive levels of explo-
sives is prohibited.
The experience gained by conducting sensitivity tests on many contaminated
sites containing different levels of contamination revealed that explosives-
contaminated soils could often be treated as normal soils. However, they have
also determined that soils containing more than 12% (120,000 mg/kg) secondary
explosive by weight are likely to initiate and propagate. As a conservative limit,
it is considered that a soil containing more than 10% secondary explosives by
weight (100,000 mg/kg) must be considered as explosive and a number of safety
precautions must be implemented when sampling and treating these soils and
they must not be shipped off site.
It should be noted that concentrations as high as 100,000 mg/kg of second-
dary explosives are rarely encountered and often a visual inspection will identify
the presence of pure explosives in the soil. Recent experience has shown that
these high levels are not to be expected in training ranges, since present day
military activities tend not to lead to high levels of explosive contamination.
Such high levels have, however, been found at old explosive production sites,
where production waste was dumped directly in the ground or in lagoons or in
areas where open burning of off-spec material was conducted. The slow evap-
oration of these lagoons may have allowed the accumulation of high levels of
explosives in the sediment.
When a site is suspected of being contaminated with high levels of explo-
sives, a preliminary sampling of the worst contaminated area should be carried
out. Surface soil samples (015cm) only should be taken and no drilling should
take place. If shallow depth subsurface sampling is necessary this task should be
performed with extreme caution using nonsparking hand augers. Representative
composite samples of the worst area should be built and analyzed. This is a good
example of where the field methods can be very helpful. Since these tests can be
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