Alum Pot Easter Cleanup

Mark R

Well-known member
Thorough research and consultation with Natural England carried out by Mark Sims led us to conclude that the old water  tank discussed on UKC  here...https://ukcaving.com/board/index.php?topic=21647.0 was indeed rubbish and should be removed from the cave. Over the Easter weekend the Buttered Badgers and UKC visited Alum pot with the aim of removing the tank. Based on some rough measurements given to us by recent visitors we had estimated the weight of the tank to be around 150kg (once it was emptied of cobbles and sand of course).

With the hefty weight in mind we took a 12? petrol Stihl saw underground with us to cut the tank into pieces. Three out of the team of five arrived at the bottom of the cave to begin emptying and cutting  the tank whilst the other two helped finish off some filming in Long Churn. It didn?t take long for the three of us to empty the tank and roll it over in the chamber, soon after we decided it would be far more fun to try and take the whole thing out of the cave in one piece.  I thoroughly enjoyed carrying the petrol saw to the bottom of Alum and out again that day.

We punched several holes in the tank with a large chisel and lump hammer and threaded wire strops through.  The three of us had managed to get the tank around half way back to daylight before the remaining two turned up and helped us fight it to the bottom of the entrance shaft. The tank put up quite a fight in several places, getting itself well and truly wedged at one point. Friday?s work concluded once the tank was sat at the top of the short pitch at the bottom of Alum Pot. All that was left for Saturday was to haul it the 80 or so metres to the surface.

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The tank gets wedged and the haulers get some encouragement...

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Some hanging around was inevitable.

On the Saturday we were joined by around 20 other sport cavers, all making their way into the cave by every conceivable entrance. Great care was required to keep the hauling operation and the sports trips separate but everyone was extremely patient and we soon had the tank lying on top of the bridge. It waited there for quite a while until much of the cave had cleared before we took it the rest of the way to the surface.

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A tensioned line kept the tank away from the wall on it's final leg to the surface

Even the most efficiently rigged 3:1 pulley system was not sufficient for two people to make any decent progress so most of the hauling used 5:1 systems.
Many thanks to Tim and Jane Allen for accommodating us for the weekend and to CAN Geotechnical Ltd for lending all the tools and hauling equipment we needed to do a proper, safe job of the clean up. Finally, thanks to Natural England for permission and for supporting the project.

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No wonder it was such an effort to pull out!
 

Mike Hopley

New member
Saw you there for a chat when you were finishing up. Brilliant job, very impressive work! :)

This thing made almighty noises as it was being moved around. I was rigging Diccan, on the second pitch, when this ungodly deep booming, roaring noise came at me over the crashing of the water. It was the tank sounds carrying through solid rock -- but I didn't know at the time, and briefly wondered whether it was my impending doom in the shape of a freak flood pulse or a collapse!
 

MarkS

Moderator
Mike Hopley said:
Saw you there for a chat when you were finishing up. Brilliant job, very impressive work! :)

This thing made almighty noises as it was being moved around. I was rigging Diccan, on the second pitch, when this ungodly deep booming, roaring noise came at me over the crashing of the water. It was the tank sounds carrying through solid rock -- but I didn't know at the time, and briefly wondered whether it was my impending doom in the shape of a freak flood pulse or a collapse!

Ahh, good to put a name to a face (or vice versa)!

Yes, it was quite remarkable how any bump or movement of the tank against the rock caused such an incredible sound!

The tank has now been recovered from its temporary location by the wall.
 

cavemanmike

Active member
i hope you where all wearing gloves as i know quite a few( possibly yourselves inc) cavers that have used that tank as a pee pot  :eek: :eek:. not me by the way  :halo: :halo:
 

Badlad

Administrator
Staff member
Some people asked how we hauled that ridiculous metal tank up the shaft.  Of course Mark R carried a Stihl saw down the cave on friday to cut the tank up but concluded the fumes might be too much and anyway it would be more fun to haul it up in one piece.  So...

The bottom section was a straight haul up to the underside of the bridge using a tag line at the bottom to keep it clear of the wall as it rose up the first 10m.  Apparently a 3:1 wouldn't cut it and extra mechanical advantage had to be added to make progress.  From here it was transfered onto a cross haul from an anchor slightly higher up on the left and also off one of the traverse line anchors in the washed out bedding.

wl


This then raised it up to a height about level with the top of the boulder bridge and a tag line pulled it onto the top.  From here it was a big pull up to the surface.

wl


We used a tension line in the configuration shown but with the tank where the person is (he is just using the rigging to abseil down to the ledge).  This is easy to rig from the big tree down to the traverse and is a system we used many years ago to give some terminally ill motor neurone suffers a final look at the cave - and they were not as heavy as that tank!

On the surface, pulleys redirect the tension and hauling lines to the base of a tree near the wall.  I think the photo actually depicts tensioning up the line but it does give some idea of the system and shows one rope in a Grigri and one in an Industrial descender.  Again a 3:1 would just not cut it and this was turned into a 6:1 which was still a fair old struggle.  I am looking forward to finding out what the tank weighed as it felt well over 100kg - unless of course it was wind resistance which slowed it down  ;)  Well done all.

wl


 
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