Depth through thought

OUCC News 9th November 2011

Volume 21, Number 9

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Editor: Andrew Morgan

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A Little Expedition - Part II

Rob Garret

[part 1]

Day 2 of the expedition and our new target was Updraught. This was the most remote part of #2 Great Cave about 2 hours from the entrance if you're moving fast. Almost entirely explored during winter time (owing to the risk of flooding in the lower regions of the cave in the event of unfortunate weather) it was known to draught strongly - a very good indicator of significant passage beyond. It gets its name from the dry blasts of air which flow up a series of intimidating climbs explored from the bottom up but now happily roped. In winter, however, the airflow reverses direction bringing warm humid air down the climbs. One consequence of this is that the normally dusty climbs were now unpleasantly slimy. Updraught itself, is a 15m chimney un-lined climb which had now become "a serious proposition". It does have a bypass which was less affected by the change in conditions but since this had always been regarded as "a bit of a serious proposition" and required extra travel the choice was a bit of a Hobson's. This should really have a hand-line one it was the unanimous consensus, if only we'd had one.

Nevertheless, onwards and upwards and into the unknown. The wind was not as strong as it had been in the summer but this was a relief as it meant that the passage wasn't quite so cold. Steady progress in a mixture of crawling and stooping passage followed by more crawling and stooping, was a lot more pleasant than it sounds as the floor was generally nice, soft, and sandy.

According to the survey we ideally needed to head anywhere between South and West and to gain steady height as we went. For the first few hours, however, we were drifting slightly east of south and losing height. This carried on until we reached a hole in the floor. Down below was a rift passage with a stream coming in from the west and flowing on beneath the floor of our passage but in a similar direction. The draught split giving no clear indication of which was the best way on so we kept with our original passage and were soon rewarded with another fork. At this point the draught was coming from a rising passage to the West. The stream was again seen descending to the east, but without any draught.

The rest of the trip was all most promising with slightly reduced passage dimensions being offest by the increased lure of a proportionally increased draught. Finally it was time to head out but back on the surface all our new survey data was dutifully entered into a computer ready for careful analysis. Overall we had gained about 1m in height but more encouragingly we had halved the horizontal distance between our start point and a hoped for connection. Our passage now had less than 300m of horizontal distance to cross and maybe 40m of height to gain. If it held true to its recent trends a connection was practically guaranteed on the next trip, at least in theory...[part 3]