Persil gets longer (well a bit)


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The return to caving on Portland...

Persil rift, discovered in the early 1980's is a short but sporting rift which previously ended at a 'flowstone blockage with a view beyond'.  It was proposed to be the continuation of Grand Canyon in Ariel Cave and hence has potential to provide a back door to Portland's best cave.  I first visited this site around 15 years ago and although at the time I had zero interest in digging, decided it was a good idea to return with a hammer and chisel.  After about 10 min effort and no progress I then confirmed digging really wasn't my thing and gave up.  The others with me had even less enthusiasm.  In the preceding years I occasionally mentioned the place to others on Mendip who likely digging but nobody seemed to bite and take the job on.  I can't say I regularly visited the cave in the preceding years but probably racked up 10 or so visits as people either wanted 'a short trip somewhere different' or some ladder practice on the 8 m pitch.  Having decided digging wasn't so bad after all, and taken on a couple of projects on Portland I though it best to have a look at the end of Persil again.  Sometime last summer a group of 5 of us headed into Persil, climbed up and down the flowstone many times (the rift is around 10 m high at the former end) and eventually decided on attempting to break through at floor level.  An hour later we decided the flowstone was in fact steel reinforced high strength concrete impregnated with granite and gave up.

Following the easing of lockdown, myself and Mike agreed to meet on Portland for a digging trip and we both thought Persil would be the ideal place as there's loads of room at the end (vertically) and essentially only one person can work at a time so a great choice for a group of 2.  We'd been talking about a return but never got around to it.  Equipped with a selection of chisels, hammers, plug and feathers and the drill we set to.  Taking turns to 'beat the crap' out of the flowstone, eventually after around 3 hours the first bit succumbed to our abuse.  Fortunately the next couple of sections gave way easier and after a further hour taking in turns to abuse the cave we managed to wriggle through.

Mike set off first and had the pleasure of being the first to explore around 20 m of sizeable (for Portland) rift which was extremely well decorated.  At the far end we quickly and minimally scrapped out a tube we could both just about fit through to find a small terminal chamber with the route ahead thoroughly blocked with mud and flowstone.

We returned a few days later with Gaynam to enlarge the route we'd dug past the flowstone, enlarge the tube to the end and also to start digging at the terminal chamber.  Again this worked ideally as we had 3 locations and 3 people.  The enlargement work proved successful, however the end looks like a long term project.

Naturally we needed to know whether the extension lies anywhere near Grand Canyon and hence one further trip to survey the cave was undertake.  The good news is that we've halved the distance between the two caves and Persil is heading straight in the right direction.  The bad news is that there's still around 20 m to go.  Now bear in mind the 'view beyond' at the end of Persil had been known for 40 years and nobody had done anything about it during that time.  Furthermore, I'm guessing the cave probably sees at most 1 group a year - what's the chances of coming out after surveying the discovery to find another caver equipped with digging kit to 'have a go at the flowstone end!'.  That was certainly a surreal moment.  Pity really, if we'd been a couple of weeks later we'd have been saved the effort.

I've not yet finished drawing up the survey, but there are photos (many photos)...

I'll start with the former end of the cave:


Which is now looks like this (I've pretty much settled on the unconventional feet and arse shots rather than faces!):


And then onto the pretties around the corner...










And in true Portland style every new piece of cave has a dodgy boulder:


The tube to the final chamber:


Pretties in the final chamber:



And apparently there's no formations on Portland!  Well they are there, just hidden.  One thing I've always admired with the formation on the island is the breath of colours.  There's very little white stal but a quite amazing range of orange, yellow and reds.  Just out of interest, can anyone shed light on the greys?  There's more nearby in Ariel but otherwise seems to be limited to that part of the island.


Good write-up and good pictures! Thanks for sharing  (y)

Mike mentioned this place the other week and pretty much convinced me that I ought to make the journey down to Portland some time :)

Ed W

Excellent result Tim!  I also tried to enlarge this back in the 90s, but like you came to the conclusion it was armour plated!  Dom Sealy did manage to get through the initial flowstone constriction (he was REALLY good with squeezes) but no further.

Another bit of the jigsaw comes into place, and another entrance to Blacknor a definite possiblity.


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Not sure I'm going to believe anyone who tries to tell me stal is delicate anymore.  Nothing which takes 3 hours of more or less continuous hammering to get it to crack through having been initially drilled and partially split with plug and feathers is delicate in my mind.

Well here's a bit more of the jigsaw...

I've plotted the centre line data for mine and Mike's survey of Persil in blue on google earth and then sketched an overlay of the useful part of Ariel Cave in Red / Pink based on Mike Reads excellent survey.  The phreatic tunnels are red and the rifts pink.  The rift in Ariel which Persil appears to be heading straight towards is Grand Canyon.


I've also updated the Portland website with further photo's and description:

For those who follow my ramblings and interested, mine and Richard's 'end of Steve's' dig aims to join the rift in the bottom left corner of the picture above.  I dream of the 'in Persil out of Steve's' trip. 


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Since the last post on here and amongst various lockdowns there has been 4 digging trips to the end of Persil to attempt to extend the cave further.  This involved breaking through a flowstone bank on the far side of the terminal chamber and then spoon out the compacted mud / rock behind.  The hope being that eventually we'd find the flowstone coming down the other side of the cone of muck.  Well that day occurred yesterday.  After approx. 2 hours and 30 loads of muck the sound changed to that of a chisel beating flowstone and a small hole approx. 10cm across was soon pierced through the crust giving a glimpse of success.  A further 30 min and the hole was Mike sized (i.e. not big enough).  With Mike bashing on one side and Richard on the other the hole was soon Richard sized, the now standard unit of measurement for Portland breakthroughs. 

So what did we find; initially a small chamber full of stal in which extreme care must be taken.  On the far side a stal bank can be crawled over to find an incredible alcove and ascending slope.  At the top the cave opens out into a sizable rift chamber which initially requires a trick 4 m free climb down flowstone to gain the floor.  On the far side of the chamber the rift splits, to the right we think will quickly yield a connection to Blacknor Hole.  Although the new bit is not surveyed it must be really close given that before yesterday the gap was only 20 m.  To the left is a tight, traversey but well decorated rift which I followed for around 15 m before deciding that was enough for one day.  Mike also descended it for quite some distance before returning.  There's also another lead requiring a little work heading back towards the entrance at a lower level that should add a few metres to the cave.  We estimate another 30 to 40 m of cave was added with further potential to investigate.

Some photos:

The first glimpse of success:


The dig:


Many formations.  These photos really don't do the place justice at all:









Happy cavers (and I actually took photos of their faces!):



And this wasn't the only breakthrough on Portland this weekend...  Another thread will follow in the next couple of days.


Well-known member
Congratulations Tim.  Hope to see a report for Descent soon  :).  Regarding stal I have been told that angle grinders come in handy to cutting into it. Up until recently impractical but now there are cordless angle grinders, something to consider.


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Another trip to Persil yesterday with a team of four - Me, Sas, Nick & Richard.  The purpose was primarily so Nick and Sas could see the new bits but whilst there the I did a rough centreline survey and made the nose of flowstone fall off which was blocking access to a void in the floor seen last weekend. 

As expected, the survey confirms the close proximity to Grand Canyon Rift in Blacknor.  I'm estimating a gap of 2 to 3 m through a currently too narrow rift.  I'm expecting a vocal connection and quite likely to be able to see each other.  Persil is shown in blue, Blacknor in red and black, the red being the rifts and the black the phreatic tunnels.  I didn't survey the rifts heading off from the far side of the terminal chamber and hence only a forked end is shown.  The one to the right (heading SE) has been explored to around 15 m at present.  The survey consisted of a single shot down this rift to get a rough angle for this passage and it appears to be heading off into the unknown.  That to the left (heading SW) is clearly, as predicted, the link to Blacknor a few metres beyond where the laser beam reached.  The cave at this point is approx. 8 m below the level of Persil entrance and therefore is roughly at the height of the phreatics in Blacknor.  On the Blacknor side there a gaps at various heights at the end of Grand Canyon and hence the challenge is working out which is best to enlarge.  The survey will be done properly and drawn up once exploration is complete.

The previously noted hole in the floor at the base of the pitch down into the rift chamber was enlarged by removing a flowstone nose to yield a very well decorated grotto which contains a couple of very nice crystal pools and an estimated 7 m of additional passage.  The end was completely choked with stal and hence will be left as nothing more than an attractive grotto to visit.

More pictures...

The survey now looks like this:

Crystal pool:

End of the hole in the floor grotto:

The other crystal pool:

Looking down into the hole in the floor grotto.  A good example of what plug and feathers can do with minimal effort.  4 x 14 mm plug and feathers.  All 4 holes drilled approx 120 mm deep.  One clean cut!



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We've only gone and bloody done it...

Since the last post there's been another 2 trips into Persil.  The first of these a fortnight ago consisted of just myself and Mike with 3 objectives.  The first to place a couple of bolts at the top of the flowstone pitch down into the rift chamber.  Although free climbable to those comfortable with a bit of exposure we soon realised some would need a handline or rope & ladder with the only natural anchor being far from ideally placed.  We also thought making the pitch hang down the right hand wall would help concentrate the mud into a specific area preserving the rest of the flowstone.  Objective two was to explore the left hand rift properly.  Immediately upon entering it's possible to drop straight down.  We estimated this to be 10 m vertically with the rift blocked in both directions at floor level.  Basically it's a blind pitch which is a pain in the arse to get out of.  So glad I followed Mike down it.  Anyone wanting to explore down would benefit from a 15 m rope.  By traversing over this hole the rift can be followed at roughly the same height for quite some distance, we estimate around 25 to 30 m.  It's fairly narrow, arduous, but well decorated.  A bit of following your nose is necessary to negotiate a couple of squeezes and a clamber over a flowstone boss.  At the far end there is an excellent array of straws hanging under a 3 m long overhang in the rift.  Unfortunately I didn't take the camera.  Beyond the straws Mike passed an extremely tight squeeze and reported there was a possible tight way down but ahead was blocked.  I didn't fit!  For those who are sufficiently slim it's definitely worth going to look at the straws (and other formations on route) but be prepared for a battle to get there and back.  These are certainly guarded by a good level of natural protection.  The third and final goal was to start bashing the right hand rift in hope Ariel cave would magically appear before our eyes.  It didn't.  In fact everything started looking tight and awkward but we didn't loose faith, for the survey said it was approx. 3 m.

Moving ahead to last Saturday (21st Aug) we got the team together so that we could have people in both Ariel and Persil.  Mike K, Mike R & Gaynam headed into Persil whilst myself and Richard dropped into Ariel and headed for Grand Canyon.  We arrived at the end of the rift about 40 min after setting off with a couple of bags of tools.  No sounds coming through the end of the rift.  Naturally I start wondering whether we're even going to get a vocal connection but Richard insisted they'd be 10 mins slower on the Persil side.  Sure enough a few minutes passed and we were soon talking to Mike K.  A bit of a rummage around and we could then see each other through a too narrow rift with a separation of approx. 3 m.  As it turned out the survey was bang on.  A more severe poke around and we'd agreed on the best bit to enlarge to make the connection and confirmed a concerted team effort would achieve our goal working from both sides.  Naturally we all set too doing our own thing!!!  On the Ariel side I started work on enlarging the widest bit.  Richard followed behind improving access and widening further.  On the Persil side Mike K attacked a low option which was more or less directly below me whilst Mike R started creating a motorway in the rift slightly ahead and above where I was working.  Gaynam was chief tool passer and spoil king.  The Ariel side was a pleasure to work on as the easiest place to dump spoil was down the narrow rift into Persil!  Several hours and 6 drill batteries later we'd got close but still nobody had passed.  Some desperation bashing and Mike K was first to cross between the caves using his low level extremely tight route.  A few minutes later and Myself and Mike R had exchanged positions through our high level route.  At present Mike K's route is incredibly small (neither me or Mike R fitted) and the other hole is very small (i.e. we both found it tight).  Being knackered, 4pm and out of batteries it was time to stop.  I accompanied Gaynam and Mike K out of Persil completing the first ever Ariel to Persil through trip whilst Mike R went with Richard to complete the first through trip in the other direction.  We all surfaced at roughly 5pm 7 hours after entering the caves.

In the next few weeks we're planning to return to enlarge the connection further to make it friendly to all.  I'm also going to put a couple of bolts in Grand Canyon as from Persil you emerge high up in the rift requiring either a trick 5 m climb or an airy traverse.  Obviously anyone wishing to explore is free to do so but I'd recommend waiting until we've had our return trip after which the experience will be much better.  I'd also ask anyone visiting Persil Rift to take extreme care to avoid damaging the formations. 

Obviously this now provides a sensible all weather entrance to Ariel cave (Blacknor Hole) and generates a number of new trips / through trips.  Alongside completing the work underground I'll update the Portland Caves website over the next few weeks to include photo's and descriptions.  Personally I think in Persil, down to Brownsea Island, then out of Ariel entrance via queen's tunnel and C&A rift will become a bit of a Portland classic taking about 2.5 to 3 hours. 

I'll update here as things progress.



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Yesterday myself and Mike returned to the Persil / Ariel connection to complete the enlarging work.  The flowstone constrictions at each end of the connecting rift  have been enlarged and the annoying boulder midway broken up.  The route through is still snug but most should fit with a fight!  The rest of the cave is sporting and contains a couple of other squeezes, so we've decided the connection should retain this character.  The ultimate test of course is whether it conforms to the standard Portland unit of measurement 'Richard sized' which no doubt will be tested soon. 

Having completed the enlargement work and picked up the pile of tools, Mike decided to do some gardening on the Ariel side as the end of Grand Canyon contained some pretty serious hanging death including a boulder the size of double bed which you needed to pass beneath!  A substantial amount has been relocated to the floor of the rift and what remains, including Mike's Mattress, is now sufficiently wedged.  Care is obviously needed as some of this lot (which we'd be stood on and under) needed very little encouragement to move.  We also put in a couple of bolts to hang a ladder or belay from to reach the rift floor for those not comfortable with the traverse alternative.  We then exited from Ariel entrance completing the though trip.

The only thing left to do now is remove a couple of drag trays, survey the new bits and photograph the pretties at the end of the left hand rift.

Our other objective was to get a few more photo's of the new bits:

The pitch into the rift chamber:


The pretties...


Descent down the right hand rift to the Ariel connection:

The breakthrough point:

On the balcony having emerged into Grand Canyon:

Mike posing with his tool out again:

If you go exploring enjoy, it's a cracking little cave now - it would be great to see someone else's report / photo's on here.  Persil could really do with some proper photo's taken by someone who knows what they're doing with a camera!


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Only one Portland caving book ever written and you?ve managed to make it completely out of date.

Thanks a bunch?


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I was adding up the numbers in my head last week; I think we've added around 500 m of cave to the island over the last 3 or 4 years and in the process forged 4 new connections between existing caves.  We're not done yet either!