Author Topic: One month and one kilometre in the North York Moors  (Read 5708 times)

Offline Cavematt

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Re: One month and one kilometre in the North York Moors
« Reply #25 on: October 09, 2020, 09:59:37 am »
Hi Tamarmole. Guinevere's Slit Sink is roughly around the lowest of the four arrows pointing to the other sinks in the River Dove. It is in the riverbed and has been dived for about 50m downstream towards The Well, reaching a choked area about 50-60m upstream of The Well (no way on located as its just very loose slabs). We assume that The Well is simply the downstream continuation of the same passage.

The Well is just off the bottom of the image under where it says 'To Bogg Hall???'. The Well drops into totally sumped, reasonably spacious passage and has been dived for about 80m downstream I think, also ending at an area of collapse, but with extremely high flow rate rushing through the boulders. The passage heads back under the river and the western hillside rather than straight for Bogg Hall so presumably it turns south somewhere soon after.

Therefore, none of the new passages in Jenga come too close to Guinevere's Slit or The Well and their associated passages. We assume the merger with the Excalibur/Jenga water lies further downstream closer to Bogg Hall.
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Offline Goydenman

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Re: One month and one kilometre in the North York Moors
« Reply #26 on: October 09, 2020, 11:03:34 am »
wow fantastic achievement well done team...turning into such a key system

Offline Cavematt

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Re: One month and one kilometre in the North York Moors
« Reply #27 on: October 09, 2020, 06:34:22 pm »
If anyone is wondering what caving in the North York Moors is really like, these three videos (all a few years old now) sum it up well...

Excalibur Pot walkthrough (the classic sporting route)
(This was mainly made for a presentation at the local village hall so apologies if it seems a bit dumbed down to a caving audience)



A trip through Bogg Hall (the resurgence for all the caves discussed in this thread):
(A superb effort by Ali Rollinson and Ade Turner utilising the 'light raft' which worked remarkably well. The final chamber is The Font, which is 18-20m deep and all the water from Excalibur Pot, Jenga Pot and the River Dove comes up from the bottom of it. Bogg Hall is a magnificent short trip).



What it's like digging in the North York Moors:
A perfect depiction of the efforts that have led us to where we are now!


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Offline tamarmole

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Re: One month and one kilometre in the North York Moors
« Reply #28 on: October 09, 2020, 10:01:47 pm »
Hi Tamarmole. Guinevere's Slit Sink is roughly around the lowest of the four arrows pointing to the other sinks in the River Dove. It is in the riverbed and has been dived for about 50m downstream towards The Well, reaching a choked area about 50-60m upstream of The Well (no way on located as its just very loose slabs). We assume that The Well is simply the downstream continuation of the same passage.

The Well is just off the bottom of the image under where it says 'To Bogg Hall???'. The Well drops into totally sumped, reasonably spacious passage and has been dived for about 80m downstream I think, also ending at an area of collapse, but with extremely high flow rate rushing through the boulders. The passage heads back under the river and the western hillside rather than straight for Bogg Hall so presumably it turns south somewhere soon after.

Therefore, none of the new passages in Jenga come too close to Guinevere's Slit or The Well and their associated passages. We assume the merger with the Excalibur/Jenga water lies further downstream closer to Bogg Hall.

Thanks for the clarification.  This is the system we dreamed of in the 90s when we were grovelling around in Dowson's and Lingmoor.  Awesome work indeed.

Offline RobinGriffiths

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Re: One month and one kilometre in the North York Moors
« Reply #29 on: October 09, 2020, 11:25:20 pm »
So these are actually phreatic systems and not tectonic caves like the windypits? Are there other places in the NYM where such systems might develop?

Offline tamarmole

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Re: One month and one kilometre in the North York Moors
« Reply #30 on: October 10, 2020, 09:02:32 am »
So these are actually phreatic systems and not tectonic caves like the windypits? Are there other places in the NYM where such systems might develop?

Whilst the North York Moors are probably best known for the windypits (slip rift features) the Hutton Beck/River Dove System is a bona fide water formed cave.  There are fossil fragments of water formed cave across the southern part of the Moors notably Kirkdale cave and the Kirbymoorside caves.  There is also some interesting (unentered) subterranean water flow such as the rising at Howkeld (again near Kirbymoorside).

The great thing about the North York Moors as a caving region is that it is far from played out.

Offline Cavematt

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Re: One month and one kilometre in the North York Moors
« Reply #31 on: October 10, 2020, 11:49:02 am »
Tamarmole is absolutely spot on (Tamarmole; who are you... feel free to PM me).

The Jusassic limestone of the North York Moors spans from Sutton Bank more or less all the way to Scarborough, a 30 mile stretch, covering the bottom few miles of the National Park. There are abandoned phreatic relics all across the area, but most are fully choked with mud. At Kirkdale, there is a 300m abandoned phreatic system called Kirkdale Cave perched several metres above the present day course of Hodge Beck. This will be in the same bed of limestone as Manor Vale Caves in Kirkbymoorside, and no doubt these systems are far more extensive than their current mud/block-choked limits suggest. Phreatic caves will have played a much greater role in the hydrology of the area following previous ice ages. Phreatic relics can be found everywhere, but very few can be extensively explored today.

You are right that some of the major caves are slip-rifts (Windypits). Most of these are between Sutton Bank and Helmsley, with the most substantial ones being part of Duncombe Park Estate (and sadly off-limits to cavers due to no public access to the Estate and the sites being archaeologically sensitive).

Several rivers sink as they cross the limestone; The Rye, Riccal, Hodge Beck, Dove, Hutton Beck, Seven, Derwent etc, with resurgences typically around the A170 road. There may well be systems to find underneath all of these although whether they are totally sumped shallow systems such as the main underground flow of the River Dove, we don't know. There is a huge resurgence pond just next to the road to the west of Pickering (Keld Head) which must have an active system of reasonably proportions feeding it somewhere. We had a project at Gundale, one of the suspected feeding streams, a few years ago but without success.

Undoubtably there is a lot more to find in the area and we've already got our eyes on a few projects outside of the Jenga-Excalibur area, but it isn't easy and the area lacks all the tell-tale signs of other caving regions, and lacks the ease of access of the Yorkshire Dales. We know of one major flood-responsive sink quite high up on the limestone a few miles east of the Jenga-Excalibur system. This has all the hallmarks of a sink into a cave system, although we are struggling to get the necessary permissions to dig there at the moment, but we are still working on that. It's enough to keep us busy for many years to come.
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Offline Cavematt

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Re: One month and one kilometre in the North York Moors
« Reply #32 on: November 25, 2020, 12:19:19 am »
York Caving Club have just made our first two journals freely available as a PDF download on the publications page of our new-look website (launched just this week):

https://yorkcavingclub.org.uk/publications/

These journals are a record of all work done in the North York Moors from 2006-2013 as part of a collaboration with the North York Moors Caving Club (NYMCC, formerly Scarborough Caving Club). They cover the exploration of Excalibur Pot, and the discovery and exploration of the first 500m of Jenga Pot, as well as exploration in the River Dove valley, and an assortment of other smaller discoveries elsewhere.

Printed copies will always be available to anyone who, like me, prefers physical journals to digital.

In combination with the resources available on the NYMCC website (www.nymcc.org.uk) including MSG journals back to the 1960s, the Scarborough Caving Club and Yorkshire Underground Research Team (YURT) archives, and all the Moorland Caver cave descriptions, there is plenty of reading for anyone interested in cave exploration in the more obscure northern limestone outcrops.

Journal Three is in preparation for 2021, covering the last seven years of progress.
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Offline Goydenman

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Re: One month and one kilometre in the North York Moors
« Reply #33 on: November 25, 2020, 11:26:14 am »
York Caving Club have just made our first two journals freely available as a PDF download on the publications page of our new-look website (launched just this week):

https://yorkcavingclub.org.uk/publications/

These journals are a record of all work done in the North York Moors from 2006-2013 as part of a collaboration with the North York Moors Caving Club (NYMCC, formerly Scarborough Caving Club). They cover the exploration of Excalibur Pot, and the discovery and exploration of the first 500m of Jenga Pot, as well as exploration in the River Dove valley, and an assortment of other smaller discoveries elsewhere.

Printed copies will always be available to anyone who, like me, prefers physical journals to digital.

In combination with the resources available on the NYMCC website (www.nymcc.org.uk) including MSG journals back to the 1960s, the Scarborough Caving Club and Yorkshire Underground Research Team (YURT) archives, and all the Moorland Caver cave descriptions, there is plenty of reading for anyone interested in cave exploration in the more obscure northern limestone outcrops.

Journal Three is in preparation for 2021, covering the last seven years of progress.

Excellent journal of your amazing explorations....well done team

Offline Cavematt

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Re: One month and one kilometre in the North York Moors
« Reply #34 on: April 26, 2021, 12:09:26 am »
Over the past few weeks, we have been back at Jenga Pot. As soon as lockdown eased and we were allowed out, work started to repump the three sumps that lie between the entrance and the estimated 1km extensions made last year.

As the first flood of Autumn 2020 arrived in early September, we left knowing there were some issues with one of the pumps, and after a winter of flooding we expected a lengthy task involving needing new wiring, connectors and maybe a new pump for sump three. We fired up the surface generator to burn through a few tanks of fuel ahead of the first week of work. The generator is connected by 150m of wire to the pumps in Sump One and Two, so in theory these should start pumping without us even having to go underground!

The following Wednesday, the first team of the year headed underground, finding Sump One empty, so the pump here having done its job nicely.

Through Sump One and into Dinosaur Penis Bone Chamber (a large mud bank in a cross rift separating sumps one and two), and we found Sump Two still quite full. We quickly realise that the reason for this was that the pipe from the pump, which is meant to go into Sump One, had floated around over winter and now Sump Two was pumping into Sump Two. Bugger!

With the pipe repositioned, we left Thirsty Jenny to finish her tank of petrol until the wee hours, hopefully draining the dregs of Sump Two while we slept. Next week we got through Sump Two with ease and onto Sump Three, which of course was full. Although each sump has its own pump (with sumps two and three pumping into sump one, and sump one to a hole 100m away into a lower drainage level), only two pumps can be run at once by the generator.

A convenient switch in Dinosaur Penis Bone Chamber allows switching between pumps two and three, so this was immediately switched over.

Pump Three unfortunately did not start first time, but some fettling of the connections and it whirred into action spouting water back into Sump One. The explorer must then play a game of ‘chicken’ in Dinosaur Penis Bone Chamber, watching as Sump One fills much faster that it empties and seeing how close they dare allow the water level to get to before turning off pump three and allowing pump one to clear the exit route. An experienced player of this game will ‘chicken out’ at about two inches of airspace, but a true grandmaster will allow their exit route to sump completely, putting absolute trust in pump one not spontaneously pack-in (a high-risk strategy as, like some of our diggers, it is very old and well overdue a complete failure).

We left Sumps One and Three pumping that night, and Sparky, our most local digger, popped down to fill the tank a few times over the week to keep it running for a few evenings. It is great to know that ‘digging’ is happening even while nobody is actually underground!

Wednesday 14th April came, and a group went down and were able to pass all three sumps.

The next Wednesday (21st) we turned up for surveying, to carry on where we left off last year.

The new extensions, Pandemic Passage, were a real treat, with the wormcasts and winter flooding having ‘reformatted’ the cave, erasing all signs of our handprints on the floor and mudbanks from last year, it was as if we were exploring it again for the first time. The streamway was met, which last year was only a gentle flow, but this time it was deeper, more turbulent water. Despite the month of dry weather, the proximity to winter means that the ground is still wet and percolation feeders are still extremely active. It was a pleasure to see this passage as a vigourous stream.

Last year we finished surveying down to Sump Five (the downstream sump of this new stream), however, a dry right branch passage was only partially complete, with some of the most critical parts of the extensions, including a chamber with tree roots, and The Second Wave, a passage which leads up to a reunion with what we think is the Excalibur Pot Streamway, left unsurveyed.

Tonight’s job was to get to Tree Root Chamber, which is a mere 80m of surveying from where we left off last year, but in low, wet and very ‘organic’ smelling canals. Thrutching through the cave in a full 5mm wetsuit was hard work, and the subsequent surveying was in the direst conditions imaginable. Despite this, four hours after we entered the cave, we emerged successful; the location of Tree Root Chamber relative to the surface is now known but is on land we cannot get permission to dig. The hopes of a new entrance here seem remote.

The other branch which we passed while surveying, The Second Wave, heads northwest we think, and should re-enter land owned by a landowner we have good relations with. A tall, draughting aven (Vaccination Aven) rises just before we meet the suspected Excalibur Streamway. Vaccination Aven provides our best changes of an entrance into the system from the next valley, thus allowing visitors to see these extensions without pumping three sumps. A very promising surface dig is ongoing at the predicted site, and we can’t wait for long warm summer evenings there with a few beers.

We need another two surveying sessions to finish the work in Jenga, but unfortunately, a 7m long duck only a short distance up The Second Wave, was found on Wednesday during a quick recce to be somewhat fuller than we remembered. Previously this was helmet off, head sideways, but nothing of particular concern, but on Wednesday it was no more than two inches of airspace and not easily surveyable. It seems a few more weeks of the cave being dry is needed for some more of this water to percolate away. Nonetheless the passage leading up to this point was as splendid as ever, and John Dale was able to get a few quick snaps.

A successful start to the year!
« Last Edit: April 26, 2021, 12:12:24 am by GarDouth »
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