Digging in Showerbath Cave, Portland

[tim.rose2]

Another couple of hours in Showerbath on Saturday - Myself, Sas, Nick & Sam being the team.

First job was to reduce the boulder left from the last trip.  Secondly the last couple of roof boulders blocking the way on were un-wedged and reduced in size.  Nick took the broken rocks back to the original breakthrough point, whilst Sas and Sam managed the evictions from the entrance.

Next I decided to make the awkward corner considerably less awkward.  This produced a load more spoil much to everyone's delight.  We were back into the new passage.  Myself and Nick took turns to work along the new bit, chucking back any rocks which were annoying.  It's tight and as yet there is no turning point.  Nick then stacked a few rocks on the shelving and continued passed our previous limit of exploration for a few metres.  He stopped at an awkward slab in the floor which needs to come out to make life easier.  Essentially the end is open at present with a view of approx. 10m.  Nick's also hopeful a turning spot might exist about 5m on.  Unfortunately it was time to leave - Wellington Hole awaited (see other thread)!

The next trip should be interesting & we'll be reporting an increase in the length of the cave.

I'm afraid no photo's this time.  Having trashed a camera by lying on it whilst messing around in another cave before heading the Wellington on Friday I didn't want to tempt fate and do the same again.

 

[tim.rose2]

Another few hours in Showerbath today - just myself and Richard this time.

Since my previous report Richard (our cave fairy) had been into Showerbath and done some spoil clearing left over from the previous trip, so a nice clean starting point again.

Today between the two of us we shift 15 tray loads of rocks and 1 large boulder from the 'new' bit of the cave.  This included the majority of what Nick had previously stacked along the shelving, the awkward slab which marked the previous limit of exploration (the boulder), the remains of the pile of stones at which we'd previous measure the length of the cave too and a selection of loose stuff out the ceiling.  In doing so I've managed to make a turning area (for small people) approx. 10 m beyond the last place, this allowed the first few non-reversing trips to 'nearly the end'.

All this allowed better access beyond Nick's previous stopping point to assess what's next.  Approx. 4m beyond, the floor becomes 'calcited mud' and raised towards the ceiling making further progress impossible.  As always with Showerbath the blockage is no more than a couple of metres long with a view to a few more metres of open but tight passage beyond.  We've dealt with this calcited mud in one previous area in the cave and it's a bloody nightmare.  Furthermore there's bugger all room to move.  We think the next job is going to be a massive effort to lower the floor (mud infill) all the way from the breakthrough corner to the end to provide more room to attack this blockage and make spoil removal significantly easier. 

Given that we have a definitive 'end of the cave' at present and that it's become hard work we'll probably park this one for a while and go look at some other sites for a bit.  Life gets stale if you keep going back to the same place.

I've not measured to the end, however I would estimate the total cave length now to be 40m.  So in 9 digging sessions over 5 months we've added a good 30+m to the cave.  There's still a draft coming from the end and a view to 'open' passage.  The cave took a couple of 90? bends creating a dog leg of about 5 m but the passage is still roughly following the cliff line (I think).

 

[mikem]

Have you looked further along the cliff for other holes it might connect to?

Mike

 

[tim.rose2]

There's nothing obvious which can be seen from the path running below the cliff but a more thorough inspection could well be worthwhile (along with the whole cliff line down to Wallsend cove the other way).  The draft could well be emanating from a too tight rift connecting to the cliff beyond the current limit - there's plenty of these.  I think we've already passed 3 or 4 in the cave which I'm pretty certain all link to features on the cliff.  For the moment though the draft is definitely coming along the tunnel.  I don't think we're heading towards any known part of Sandy either (which does have a gale blowing through it).

 

[tim.rose2]

Yesterday myself and Nick thought it was about time we returned to Showerbath to have a look at attacking the end of the cave having not done anything in there for over 2 years.  For a while we'd spoken about a return but never found the right moment.  Equipped with a bag of tools we headed over to the cave just about dodging the start of the rain.  Since giving up on the place Richard had popped in during the winter whilst out for a walk and reported the place being very wet and full of puddles - something we'd not seen previously.  Yesterday however the cave was bone dry even with it pissing down outside. 

The end was exactly as I had remembered - a calcited lump in the floor with mixed in mud and rocks blocking the way ahead, with a view beyond into the continuation of the tunnel which appears to be 'open' passage.  We also soon remembered how bloody long and small the tube we'd previously found was to get to the end, and more importantly how little room there is to move to do anything.  Never-the-less we took turns to swear and moan, slowly retrieving spoil from the end and ferrying it back 20m to chuck down a small rift in the floor I'd opened.  Over 4 to 5 hours around 15 loads were removed which included clearing odd and sods from the existing passage.  In all reality the blockage would be passable as a squeeze if a few calcited in rocks were removed, however the raise lump restricts space so much just before the key bits it's impossible to wield a hammer, chisel and crowbar to deal with them.  The only course of action is to take up the calcite floor & rocks which cover a distance of around 2 m.  Yesterday I think we advanced around 0.5 metres!  We now know what we're doing and as mentioned cleared the route to the end a bit so with any luck 2 more sessions and we might be through.

Yesterdays main observation related to the drafts in the cave.  Previously we noticed strong outward drafts, however (bare in mind it was gale force winds outside) we noticed the cave drafting strongly in both directions with frequent changes in direction.  Presumably the continuation connects to something open to the cliff (probably a rift) and the direction of the draft related to exactly which bit of cliff was subject to a gust.  This is not something I've ever noticed underground previously.

No photo's from inside the cave, but I did take one outside the entrance showing the delightful weather.  Portland is a truly magical place in a good storm.

 

[mrodoc]

Keep up the good work Tim

 

[tim.rose2]

Another day in Showerbath and a few more metres gained.  Myself and Mike R met on a wild and windy Portland at 10am and headed down to the entrance, getting a thorough drenching on route whilst climbing down the gully at the end of Sharbutts quarry.  Once in cave Mike headed straight to the end to complete the first shift of digging whilst I set up a carpet hauling system.  It turned out there was only one shift!  Mike kindly did the hard work all day whilst I dragged out carpet after carpet of spoil.  I'd guess at least 25 loads were removed.  Small stuff and dirt went down a rift (which is now full) and the larger rocks got chuck aside to be dealt with another day (or perhaps the cave fairies will deal with it before we return?).  After several hours Mike announced he was nearly through the blockage and the passage ahead was 'open'.  Another 20 mins of scraping and chucking rocks out of the way Mike suddenly disappeared through a tight wriggle into approx. 5m of new passage.  Due to the lack of passing places I didn't bother to have a look at the furthest point myself but Mike said he could see another 5 to 6 m of open passage beyond an annoying rock which would need breaking up to pass.  Today's breakthrough was a bit of a rush job as we were fairly knackered so we've also got a lot of tiding up and some enlarging to do next time but with any luck we should report another few metres at least on top of todays addition.  I'd guess the cave increased in length by around 8 m today so Showerbath must be getting close to 50 m long now.  Only another 10 m and by Mendip standards it would be a principal cave worth visiting!  Big draft again today - I'm certainly keen to find where it's coming from; I'm convinced Showerbath hides a secret beyond it's tiny passage.

Some photo's:

Carpet drag tray in use in the cosy passage beyond our previous breakthrough point in 2018.

Mike working at todays breakthrough point:

Looking back towards the entrance, wellies for scale!

The awkward wriggle - today's breakthrough point:

Today's new passage:

 

[mrodoc]

Let me know if you want some lightweight conveyor belt. Also have you a capping facility because if not we might able to help

 

[tim.rose2]

It's been a while, but today has marked a return to Showerbath. Just Nick and I for a few hours farting around. We started by clearing previous spoil which had never been tidied up. Then surveyed to the current end (something I'd been meaning to do for a long time) and finally had a look at the boulder pile at the end of the cave. I emptied a drill battery cutting up rocks into pieces with are small enough to take out and then we removed some of these. Due to the size of the passage it's basically 1 bit at a time back 30 m to where the cave is a bit bigger and so 3 or 4 trips to the end and back is sufficient for one session. We've left another 4 or 5 bits ready to take out next time and there's still at least one other rock to reduce into manageable bits. Some space creation will also be needed. The very end of the cave currently gives a view along the continuing phreatic passage however is guarded by a very dodgy ceiling which seems to be held up on a couple of pebbles - the fun to come!

The survey shows the cave to currently be 48 m in length though rather surprisingly more or less follows the cliff line rather than heading more inland as I'd expected. Showerbath is Pink, Gold & Silver passage in Sandy is Blue. I didn't particularly think it would be, but the survey more or less confirms that Showerbath is unrelated to Sandy.

A couple of photos:
Nick nicely showing the size (or lack of) of the passage.

Ammonite. Plenty of these on Portland.

 

[tim.rose2]

Myself and Nick spent the best part of 3 hours in Showerbath again today. I increased the 'working space' at the end of the cave by poking dirt and pulverised rocks down a 3 inch wide rift, interspersed by a bit of slicing and dicing boulders. Nick enjoyed the task of removing the boulders. I think he took out around 20 to 25 pieces out of the cave. The whole cave is a very small phreatic tube, now 48 m long. It's a long torturous way to take spoil out!

Most of the annoying rocks / boulders in the way of inspecting the end of the cave are now gone. Just a few bits which are cut up and ready for removal remain. The last thing I did was have a quick peek. The entire roof at the end is shattered and seems to be held up by very little. The dilemma - do we try to support and dig underneath (might be possible) or attempt to collapse the bloody lot and then deal with the mess. It could well result in many sessions of slicing, dicing and removal, but would almost certainly result in gaining some desperately needed space. My vote goes with the latter. I guess the decision will be made next time we're in there.

On the plus side you can see a good 5m past the roof of death and the draft is strong. What I'm not yet sure about is whether the roof of death is actually a blocked route up into a 'man-sized' rift.

 

[Mark]

On the plus side you can see a good 5m past the roof of death and the draft is strong. What I'm not yet sure about is whether the roof of death is actually a blocked route up into a 'man-sized' rift.

Looks like you are about to hit a prominent joint, could well be?

 

[tim.rose2]

The joint you've pointed out contains Anniversary Rift. Somewhere I've never got around to visiting. The cave is high up in the limestone and is accessed by installing some stakes on top the cliff and then laddering (with some creativity applied) down the scree and dropping into the hidden recess. Based on the description I've been given I'd estimate Showerbath to be approx. 15 m below. Unfortunately you can't see the entrance to Anniversary Rift from either above or below. The chap who found it in the 1970's tells me it's a very wide rift about 15 m long ending at a choke which was briefly dug. Apparently it's a promising site (which one's aren't???). I suspect the cave has seen zero (or very close to) visitors since the 1970's. If we find a rift man-sized rift in the roof of Showerbath no doubt it'll spur me on to get into Anniversary which will almost certainly be another Tim & Richard session of dangling over cliffs attached to tent pegs (well maybe something a little more robust). As always plenty to do and so little time.