chunks, dirt and other mineral matter, trash (build-
winds from the southwest carry sand particles
ing materials, paper, plastic containers) and soot
from Black Island over the runway. Observation
from aircraft and equipment engines. The best
of ice and snow cores in the area include numer-
approach for dealing with contaminants is to avoid
ous horizons of concentrated mineral particles
getting them on the runway in the first place. This
(Fig. 15 and 16), suggesting that this is a regular
will only be possible for some types of foreign
occurrence (on the order of less than once per
matter, while others may be impossible to com-
year to several times a season). Areal reconnais-
pletely control.
sance in the area between the Pegasus runway
We advocate a regular program of runway in-
and Black Island shows that plumes of dirty snow
spection with daily observation of the majority of
and ice can be clearly identified pointing in a
the runway surface (as is done at conventional
generally northeast direction. We have also been
airports). Adjacent areas should be inspected at
present at the runway on several occasions when
least weekly, except during any periods when air
strong winds were blowing and witnessed sand
temperatures are near melting; then they should
"marching over the snow surface like a massive
also be viewed daily. Any contaminants discov-
army of ants." Such contamination of the runway
ered during these inspections should be picked
is impossible to clean up. And, it can be devastat-
up completely and disposed of in an environ-
ing just prior to or at the time of peak tempera-
mentally sound manner.
tures and solar intensity.
Small spills of fuel or lubricants on the ice will
We discovered that a runway can be quite well
often require specialized cleanup procedures.
protected from such contamination by wind borne
Cleanup kits designed specifically for hazardous
deposits by using "snow fence" techniques. If it is
fluids are available and should be on site for these
known from what direction such mineral par-
occasions. Most established polar camps have per-
ticles will come, blocks can be created upwind
sonnel trained for such cleanups, and these indi-
from the runway. At the Pegasus site, we ob-
viduals can in turn train runway maintenance
served that the mineral particles traveled by sal-
personnel in the proper procedures for recover-
tation (were never carried for long periods of
ing spilled oil, fuel, coolant, or other fluids. After
time in the wind column), even when very strong
cleanup, chipping out the ice in the area of a spill
winds were present. Thus, the sand particles
may be necessary in order to completely remove
bounced along the snow surface and often would
the contaminant. This ice should be disposed of
become trapped by very small snow scarps (Fig.
properly along with the cleanup fluids. Using the
18). Being almost too heavy to transport with the
patching procedures outlined above, the cavity
available wind, we discovered that gently slop-
can then repaired.
ing berms of moderate height aligned between
Because of their lower reflectivity, chunks of
the runway and Black Island were adequate to
ice on the runway can also represent a threat.
stop the forward progress of most of the sand.
This is especially true for ice chunks that may
Extreme cases may exist in other areas where
have formed on runway equipment and fallen
larger berms or manufactured snow fences (prob-
off. These ice chunks may contain many other
ably with narrow openings) will be required to
types of contaminants as well, having picked up
remove mineral particles from the air stream be-
dirt, oil, grease and other foreign substances from
fore they reach the runway. However, windborne
the vehicle. Lying on the surface, even an uncon-
contaminants should not be a major or frequent
taminated lump of ice will absorb considerable
problem at most runway sites, since the damage
solar radiation through its large surface area and
they cause would have been obvious during ini-
will warm significantly. During the peak of sum-
tial site evaluation and the site would have been
mer, this can easily lead to the beginning of a melt
removed from consideration.
site that will progress into the surface of the run-
A smooth runway surface will be best suited to
way. Ice chunks along the flanks of the runway
resisting entrapment of sand when it is impos-
will behave in the same manner. If snow is present
sible to avoid wind blown mineral dust. Ideally,
in this area, it is advisable to attempt to bury the
most of the particles will continue to be trans-
ice pieces in the snowpack. This can be done with
ported past the runway surface. When mineral
a ripper (Fig. 30) or by using drags, planes, or
particles do contaminate the runway surface there
rollers.
are only a few options available. If, as in most
Windborne mineral matter can be very prob-
cases, there is a small amount of snow on the
lematic. At the Pegasus site, occasional strong
runway the mineral dust should be mixed into
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