Special Science Report

February 5, 2008

Kerry Cupit


Project:
Soil Gas Analysis at MDRS as a Rapid Resource and Geologic Assessment
Tool


Personnel:
Kerry Cupit


Operations Data Collected:
A field test of all soil gas equipment was conducted today on EVA-3,
crewed by three crewmembers. Three pilot holes were made. Two were
drilled by a hand auger, and one was dug by shovel.

The auger proved to be the most effective way to excavate, however the
desert soil is increasingly cohesive with depth. The following is the
results returned from each of the two drilled holes:

------HOLE 1------
Date: Feb 4, 2008
Time: 11:18AM
Depth: 2ft
Easting: 0518392
Northing: 4250624

[CH4]: 0.1%
[O2]: 21.7%
[CO2]: 0.1%
[CO]: 7-10ppm
[H2S]: 0ppm
[H2]: 0ppm

Downhole T: 6.5°C
Ambient T: 3.9°C
Barometric P: 25.58 mmHg

------HOLE 2------
Date: Feb 4, 2008
Time: 11:53AM
Depth: 10in
Easting: 0518472
Northing: 4250585

[CH4]: 0.0%
[O2]: 21.7%
[CO2]: 0.1%
[CO]: 8-11ppm
[H2S]: 0ppm
[H2]: 0ppm

Downhole T: 9.6°C
Ambient T: 2.0°C
Barometric P: 25.64 mmHg

The hole excavated by shovel was a qualitative soil strength test to
compare ease of excavation versus a hand auger at nearly the same
location. A hand auger, as mentioned, was more effective, and will be
used in the future.

Cohesive soil samples were retrieved from 20-30cm down hole #2. They
are a brown-red with white spots, well-sorted, mature sandstone.
Colouring patterns were such that the white portions were very
circular, with some fringing of red color on some white spots and not
others. Does not react with HCl. Cataloged for later study.


Technical/Equipment Issues:
The equipment worked mostly as expected, however it took a fair bit of
time to auger a hole to the desired depth (3ft). We learned a few
techniques to maximize the effectiveness of the tool, including using
two people to operate it at the same time and applying downward force
in the last partial rotation in order to get as much cohesive soil in
the bottom of the auger as possible. If sufficient downward force is
not applied, the cohesive soil gets chopped up and it is much more
difficult to lift the soil out of the hole, falling out the bottom of
the auger and back into the hole. Additionally, if each person has one
hand on the shaft and one on the handle, turning the auger with greater
force is possible.

After the hole is augered, a pipe was inserted and sledgehammered even
deeper. The T-coupling broke off due to the force of the sledgehammer,
encumbering subsequent uses of the vapor probe but not affecting the
science results.

After putting the vapor probe in place and observing the gas analyzer
readings, gas concentrations were very close to atmospheric composition
with periodic bursts of minor amounts of CH4 and CO. We concluded this
was due to an imperfect seal at the top of the pipe, with the periodic
bursts possibly attributed to soil gas. Therefore a better seal will
be needed between the gas probe and the pipe it is inserted into.

The GPS device worked flawlessly, and won't be mentioned again unless
difficulties arise.

The portable weather station used for barometric and ambient
temperature readings worked well, however during the EVA it was noticed
that the gas analyzer also measures barometric pressure. Since the
thermocouple can be used to measure ambient temperature too, we can
probably leave the portable weather station behind.


Discussion:
The pipe and gas sampler tube will be modified to effect a better
air-tight seal. A modified sampling procedure has been written,
including an updated list of required equipment.

Enough was learned on this EVA that another field trial of the soil gas
survey equipment would be ideal to see how the equipment modifications
perform before using them in an actual survey. An ATV would be a great
workbench to leave equipment on when not is use, so one will be used in
the next field test EVA.

After field trials are complete, a reconnaissance EVA on ATVs will be
performed to follow up with a soon-to-be-performed airphoto lineament
analysis.


Questions for RST:
None at this time. Know any good geology jokes?