WHERE THE CAVES ARE - The Caving Regions > Portland

Digging in Showerbath Cave, Portland

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tim.rose2:
We had planned a long weekend in either Yorkshire or Derbyshire over Easter however changed plans due to the weather.  Thursday / Friday we spent caving on Mendip (Spider & Manor Farm).  Saturday / Sunday we headed to Portland for either caving / climbing as the weather allowed.  Jump back a few weeks, following one of my recent trips to Steve's Endeavour myself and Richard stumbled across Showerbath Cave - a short section of pheatic passage ending at a too tight choke.  Another place I've been meaning to look at for years.  Shift a boulder 6 inches and a view of the pheatic tunnel continuing beyond appeared.  Seems like this was not noticed by Portland diggers of the past. 

As much as I know little about or have little interest in digging caves this seemed to easy to ignore, particularly as Portland could do with another cave or two appearing.  So Saturday pm, once the rain cleared up, myself and Sas went to have a look at what could be done.  Armed with a selection of 'might be useful tools' we wandered up the cliff.  We busted up a few boulders which were in the way (presumably left by previous diggers) and tossed them out the entrance.  Turns out an SDS drill, lump hammer and a set of plug and feathers can be satisfyingly destructive.   Time was tight (appointment in the pub) and the drill battery was dead so we gave up.

Having been surprisingly productive Saturday, Sunday we decided to go back for more and hopefully find miles of walking sized passage (some chance on Portland!). 

One final boulder was bust up to give a free run for a drag tray to the entrance from the dig face.  Turns out my garden hoe is an excellent weapon for scraping out mud.  By lunchtime enough mud / rock infill was removed to fit through.  Some wood was inserted to support a dodgy boulder.  Sas went first and soon returned to report the passage beyond was sufficiently filled with mud to prevent progress.  Me next with some tools - a couple hours later I'd chucked tonnes of soil down a rift, created a turning circle and worked along to the next annoying rocks.  Unfortunately these might be holding up the ceiling but the passage beyond looks bigger and less filled with mud.  All in all about 5 to 10m of passage gained, still with a view beyond.  That was nearly enough for the day.  Last job, one final look at that dodgy boulder - might as well use up the remaining drill battery me thinks!  Let me have the plug and feathers - crack, and down half of it comes.  Pokey pokey with a crowbar and the rest is down too.  Ok, we've left the cave blocked in the place it was when we started but 30min effort next time should have that cleared and we'll get to discover 5 to 10m of passage a second time - this time big enough to fit through.  Hopefully taking this boulder out will remove the squeeze beneath it and make it easier to remove a few larger rocks (which won't fit down the rift I'd been chucking the mud) from the passage beyond.

A couple of pictures...

Before we started today:



Me finishing digging out spoil:



Sas first through into the new passage:



The dodgy boulder:


Half the dodgy boulder on the floor and then cut in half:



And then it was gone:



Richard wanted a garden outside the entrance to cultivate his wild cabbages in, perhaps not the design he would have been thinking of but we have provided a patio and veggie patch:



Providing I can work out how to get beyond without bring the roof down on me we're going to have another go at this in the coming weeks as it still feels worthwhile.  Unfortunately removing one dodgy boulder has made the next look dodgy so this might have to come out as well before getting back to the end.

If anyone wants to help / put in the effort so I don't have too please get in touch.  I'd like another cave on Portland to play in but more than happy for someone else to find it!

Pegasus:


 :o :o :o :o ;D

mrodoc:
And I thought our dig looked dodgy!

tim.rose2:
The dodgy boulder was pretty well wedged and with the support underneath it wasn't going anywhere.  We decided to remove it to improve access beyond.  There's many boulders on Mendip regularly passed under which look much worse.

The loose stuff here is where the rock has fractured (there's a 4 to 6 inch rift on the left hand side not visible in the photos) after the pheatic tunnel was formed and resulted in the tunnel roof becoming dodgy and collapsing.  Further ahead the tunnel appears to start moving away from the rift (right handed) with the left hand wall coming back into existence and the roof looking much better (well as good as they get on Portland).  I'm working on the theory once the pheatic tunnel moves away from the rift there should be less fill and less collapses.  If things don't quickly improve this will be put on hold as I have a couple other places on Portland to look at which might yield new cave with little effort.

I spent a bit of time last night looking at this on Google earth.  Should the cave continue in the same direction it's heading straight into the area North of Sandy hole on the same level as Sandy.  One thing we were wondering is whether the water flowed in / out.  If out I'm expecting the cave only to get smaller.  If in, there's hope its a tributary to something else (possibly Sandy).  There is scalloping, however there seem to be examples which go both ways!  Neither of us could convince ourselves which way the water flowed.  Anyone have any tips to sort this out?   
 

mikem:
If it was hardly flowing then you are seeing phreatic pockets rather than scallops.

Mike

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