200
3
160
2
120
80
1
Gap Velocity (cm s-1)
40
Average Gap Velocity (cm s-1)
Slot Width (mm)
Average Slot Width (mm)
0
0
20
40
60
80
100
0
120
Distance (cm) from Pump End
Figure 9. Slot width measured along the 1.2-m collector prior to
deployment. Also shown is the corresponding gap velocity, assum-
ing a uniform distribution of 2.1 L s1 total flow.
to increase traction we manufactured longer drive
liner, and ASA constructed and installed an EPDM-
shafts that could accept a double set of heavy,
lined wooden chimney over the opening. We
spiked wheels. These same long shafts and the
sealed the chimney to the opening. This process
spare wheels also fit the 1.2-m collector (option-
ensured continuity of the EPDM liner around our
ally to increase its traction).
access hole and work area. ASA then carefully
In addition to these tests on the assembled col-
backfilled the pit with snow and constructed our
lectors, we cold-soaked individual components
work space. This work space consisted of a winch
(silicone hoses, LDPE filter arm, O-rings, etc.) at
room directly over the chimney and an adjoining
65C in a liquid-nitrogen-cooled chamber
laboratory (Fig. 10).
(Tantillo 1993) to check their flexibility and dura-
We used a hot-water drill (Fig. 11) to make the
bility. We also suspended each collector from our
second access hole to the SPWW; ASA also assisted
tower and sheave to ensure that they hung true.
with the drilling. Water from the well was heated
in boilers located in the wellhouse and fed into
the 30-cm-diam. cylindrical drill via a neoprene
Deployment
We sent two fully operational collectors to the
rubber hose. This hot water discharged through a
90-cone nozzle to melt the ice as the drill de-
South Pole with the means to make modifications
to each should the well-bottom conditions be dif-
scended. A water pump positioned inside the drill
ferent from our expectations. We also shipped a
pumped water from down-hole to the surface via
winch, tower, and sheave, two 200-m electrome-
a return hose. The drill was lowered using a winch
chanical cables, a video camera, monitor, and re-
and stainless steel cable. The hoses were attached
corder, spare pumps, filter fabric, and motors and
to the cable with stainless clamps and cloth ties.
various tools that we needed for assembly and
The cable was guided into the hole using a sheave
repair of the collector in Antarctica. The operation
suspended from a spring scale. The scale allowed
of all these components was checked before ship-
us to determine whether the drill was suspended
ping. The collectors and cables were disinfected
in air, was on ice, or was in water; this set the drill-
using a 1:60 solution of Clorox to water and were
ing rate. Drilling took about 36 hours, longer than
wrapped in plastic to stay clean during transit.
expected, but yielded a vertical, wavy-walled ac-
At the Pole, personnel from Antarctic Support
cess hole with a minimum clearance of 30 cm in
Associates (ASA) assisted us in many ways. Their
diameter.
main task was to build the surface facilities that
Prior to collector deployment, we lowered the
would provide us access to the SPWW and create
video camera to examine the hole and inspect
an adjoining work space. They first dug a pit
the well-bottom topography. We noticed that an
(about 3 m 3 m 3 m) in the snow adjacent to
ice cover had formed on the well pool and that
the existing wellhouse and down to the EPDM
the access hole through it had refrozen (we would
liner. We then cut a 30-cm square opening in the
need to break through this ice cover before each
13
Previous Page
