New stream cave in the North York Moors?

Cavematt

Cavematt

Well-known member
Up in the North York Moors, we have been treated to some great discoveries over the last decade, including a 1km+ extension to Jenga/Excalibur Pot in 2020.

However, all open and obvious leads in Jenga/Excalibur are now exhausted (except for the four sumps which await divers and are sure to add hundreds of metres more passage and possibly the fabled link to the River Dove or Bogg Hall). Also, accessing the Jenga extensions is not viable October to April due to flooding. Hence we have been on the lockout for our next project.

Should we return to some of our more speculative, uninspiring digs? Manor Vale? Mutton Butty? Glass Trap? Enthusiasm was not high for any of these.

Thankfully, last summer, a new project came to light at a site we have been interested in for some time, where a change in land ownership has now enabled consented access for a dig. This site is near to the village of Cropton, 4-5km east of the Jenga/Excalibur system, at the top end of the limestone.

Here, a small stream (which only flows when the ground is saturated) disappears into the ground at the top end of the Jurassic limestone, at the end of a usually dry valley, with about 3-4km horizontal range and 50-60m vertical range to where most of the regions resurgences are found.

Progress was slow, as getting down through several metres of upper non-limestone rock was challenging. Thankfully the really friendly landowner was on hand with a JCB to expedite this, getting us down 4m into a small, dry cave passage leading off into darkness.

This passage was not straightforward. We were not properly into the top of the limestone yet, so the roof had flaked large slabs across the passage where it has collapsed in multiple places, and progress through Autumn and Winter has involved pushing along the passage, removing boulder obstacles. At times it has felt like an underground boulder labyrinth, but in fact we are following a large passage, just one full of blocks. Progress has sometimes been only 1m per week!

The draught is excellent here, and the prospect of sinking water nearby kept us going.

It was at some point in November that the first heavy rain of winter happened and the sinking stream (The Shite Brook) suddenly entered the cave about 10m along the passage, bringing with it some foul smells for the first week of flow until it flushed through whatever the offending matter was.

The stream flowed off tantalisingly through boulders, accompanied by the ever-present-draught.

More boulder mining identified that we had now achieved a solid, water-worn roof, and solid cave walls in a passage 2m wide by 1.5m tall. The challenge was a number of large slabs that continued to block the way. In the sessions just before and during Christmas more blocks were cleared, and ahead, the most enticing black voids yet appeared, with the sound of the stream gurgling into the distance.

On 4th January, after a few more hours of boulder removal, we got a mini breakthrough and crawled forward 10m just above the stream and into a 5m long, 2m wide chamber with a few formations. At the end of the chamber is a way on, flat out in the stream and going off several metres, with no end in sight. This is our target for this week, although some dodgy blocks need to be stabilised first and the stream may need some dredging of cobbles.

We are now about 30-40m into the cave in total. The further in we get, the more water-worn it becomes, the more cave-like and phreatic it appears, and the more space we are getting between obstructing blocks (although we are far from clear of these). Plus, there is a stream vanishing into the cave and a strong draught either howling in or out (typically out, but last week it was strongly drawing in).

What we do have here for sure is the second, explorable, active stream cave in the North York Moors, if you count the entire Excalibur/Jenga/Bogg Hall/River Dove as one cave system.

Excitement is mega-high for the coming weeks. Will we get through the boulders and into glorious stream passage heading off down the valley? Will this become the second North York Moors mega-system? Or is this going to become a several year mining project through hundreds of metres of block-choked streamway? Is it going to spontaneously close down to an impenetrable wet bedding? Time will tell, but we are feeling fairly upbeat right now.

In the meantime, we have put together the following video from the session last week with the mini-breakthrough and open (albeit small) passage ahead. Enjoy…

 
Cavematt

Cavematt

Well-known member
Ps; I should have said... there is some very bad language in the video, in case anyone is easily offended.
 
G

Goose 777

New member
That is an interesting read... I live near the North York Moors. Can anyone tell me where the nearest caving club is to the North York Moors. I used to be in the Aberystwyth caving club:) thanks
 
Cavematt

Cavematt

Well-known member
A fun evening last night up at the new cave, and a good turnout of YCC and NYMCC members, despite it being a bitterly cold evening. It was fairly dry though (contrary to the Yorkshire Dales at the moment… being on the east side of the Pennines has some advantages).

By the time everyone was underground we found ourselves with eight people in the small chamber just before the active face. A few people started work dredging the flat-out crawl in the stream ahead ready for the push along it, while the rest of us manhandled blocks to create a large pillar underneath one particularly concerning large slab in the roof. Whether this will provide any protection if the slab falls, we don’t know, but it certainly made us feel better about being there.

The low streamway was pushed for 3m to where it rose up over blocks and into a crawl over slabs with the streamway below. Another 5m onwards the first pushers encountered a large block which would need a squeeze to get past, so they returned to report and then everyone took it in turns to go and inspect the situation (which took the best part of the evening).

The squeeze was pushed by a few of the thinner diggers, but only for another few metres to a point where the way on is clearly back down to the stream, as the overhead passage seems to run out. Sadly, getting back down to the stream was obstructed by slabs.

We’re going to need a few weeks of work to deal with this before we can push further. This will include engineering a route over the flat out crawl in water (for comfort rather than necessity) and then dealing with some of the slabs that prevent continuation at stream level beyond.

The way onwards in the stream isn’t massive, but it’s a definite small stream passage, crawling height, and still draughting nicely. The passage is dropping considerably and we are hopeful that not far ahead we will find ourselves into a better quality limestone capable of having developed more.

The streamway at the active face is very reminiscent of the likes of the Honey River Series in Excalibur Pot.

The dream is that this is an inlet into a system that will develop further downstream into something bigger. We’d love to think this could become the next Excalibur/Jenga, although we remain firmly grounded in reality that it could close down at any point, or there could be years of work ahead (not a problem... we have lots of time).

The total passage length so far is probably about 50-60m.

The resurgence is unknown. One possibility is Keld Head in Pickering, which is over 100m lower in altitude (much more than I quoted in the video) and over 4km away. We know that Keld Head is the resurgence of a lot of water from various sinks across the region, with the water rising up through the gravel floor of the pond, producing a substantial river in wet conditions (you can actually see the gravel at the bottom of the pond churning from the upwelling water). There are also likely to be numerous other smaller resurgences in the Sinnington to Pickering area, still with 90m+ vertical range. This is more than double the vertical range Excalibur Pot has from its resurgence!

Lots of work to do, and no stomping stream passage yet, but we are pretty excited nonetheless. This is probably the best prospect outside of the Jenga/Excalibur region we have ever had. Together with this, and assisting divers to the Jenga sumps over summer, our digging calendar for 2023 is fully sorted.

:dig::dig::dig:
 
Leclused

Leclused

Active member
Cavematt said:
The resurgence is unknown. One possibility is Keld Head in Pickering, which is over 100m lower in altitude (much more than I quoted in the video) and over 4km away. We know that Keld Head is the resurgence of a lot of water from various sinks across the region, with the water rising up through the gravel floor of the pond, producing a substantial river in wet conditions (you can actually see the gravel at the bottom of the pond churning from the upwelling water). There are also likely to be numerous other smaller resurgences in the Sinnington to Pickering area, still with 90m+ vertical range. This is more than double the vertical range Excalibur Pot has from its resurgence!


:dig::dig::dig:
Click to expand...

This looks like a nice DYE-tracing project :) Perhaps you can contact traqua to sort out some material for the tracing. The have a sponsorship procedure for dye-tracing caving projects

More information here : https://ukcaving.com/board/index.ph...eters-for-scientific-research-projects.29523/
 
Graigwen

Graigwen

Well-known member
Goose 777 said:
That is an interesting read... I live near the North York Moors. Can anyone tell me where the nearest caving club is to the North York Moors. I used to be in the Aberystwyth caving club:) thanks
Click to expand...

Hi Goose, when were you at Aber?

Did you go to the 2016 reunion or were you one of the people I could not find?
.
 
Cavematt

Cavematt

Well-known member
Wow, always pleased and surprised to see some North York Moors enthusiasts wondering about progress :)

The lack of report on this recently sadly means progress has not been as dramatic as we had hoped. At the last report, we mentioned that we were about 4m down, beneath the bottom of a shallow valley where, in very wet contitions, a small stream sinks 50m back up the valley. This was a good cave passage, blocked every few metres by blocks which needed to be engineered out of the way, until after about 10m of progress we met the incoming stream, only for this to be lost into a low wet wallow about 30-40m beyond.

We worked most Wednesday evenings at this site (Cawthorn) last year, through summer having two digging teams each week, one pushing several leads in the Jenga Pot Covid Extensions, and one pushing Cawthorn.

With the stream dry, work was able to push on at the active face, a wall of collapsed slabs, with the dry stream gully disappearing out of sight beyond but very small. The entire passage (from solid wall to solid wall) is sizable, 2-3m wide, 1-2m high, but it is relentless slabs and blocks making it feel more like a continuous boulder choke at times.

No sooner was one boulder section passed, we would often be treated to 3-4m of open passage before the next boulders.

The work progressed using plug and feather technique, including two teams, a pushing-forward team to attack the active face, and a clearup team behind to remove debris and continue to enlarge the more recent breakthroughs to a more workable size so the entire cave does not become a continuous squeeze to the active face.

The cave continues to draw-in or blow out a strong draught along the route of the stream, and it is heading south following the unusual markings on Google Earth which we presume show the former route of the stream when it flowed on the surface.

By the time the wet weather caused the stream to return (November) efforts had pushed the cave to about 90m in length, including several sections where boulders have been moved out of the way, but also a few slightly more spacious sections too.

This photo sums things up...

1712167430252.png


And this photo shows the active face around August-September time (about 80m from the entrance):

1712167475628.png


The rock is soft and mining with plug and feathers is easy (capping and other such techniques are largely ineffective as the force is just absorbed by the soft rock). The passage is still going, but no signs of the regular boulder blockages reducing in severity or frequency.

With respect to the geology, although the entrance at Cawthorn is at the top of the limestone, the passage itself is not in the main cave-forming limestone layers (the Malton and the Hambleton Oolite). We believe that this passage sits in a layer of calcarious grit, either above or below the more solid limestone, which explains its softness and why the passage has collapsed in so many places as it has formed.

We live in hope that as we get further down the valley we can somehow intercept the cave-forming limestone and the character will change and we will be into proper unobstructed passage.

For now though, this remains an active project where 1m of progress each 2-3hr session (on average) can be made. This is a summer project as during winter when the stream is flowing it is cold, wet and miserable, but in dry conditions, this is a lovely dig. The draught spurs us on, in the hope that this is just a chossy inlet into a larger system in the proper Oolite, and not a continuous boulder-obstructed calcarious grit passage all the way to Pickering.

Despite all of this, Cawthorn is the only active North York Moors cave to be explored outside of the Excalibur/Jenga/Bogg Hall/River Dove system, which is a decent title.

Our more recent winter attention has been focused on a historic all-weather dig (Mutton Butty) reported in our second journal, as well as a newer dig 150-200m downstream of Jenga Pot (Pandemic Pot), at another sink in Hutton Beck, which we hope could enter another extensive new section of the Jenga-Excalibur system. In recent weeks our Wednesday nights have seen three separate teams, one at Mutton Butty, one at Pandemic Pot, and one surveying some mines further north.

We do not lack for projects, but breakthroughs have been a bit sparse over the last few years.
 
Tritim230

Tritim230

Active member
Excellent report, Matt. Your experiences are much like our Forest projects. We have so many on-going with major potential, but many that are weather dependent. We still haven't got back to one promising lead after a breakthrough in October. Since Storm Babet, the rain hasn't stopped. Fingers crossed the weather will relent as many more kilometres surely await.
 
Cavematt

Cavematt

Well-known member
Three months since my last update. Exploration in the North York Moors has been continuing with enthusiasm, despite the lack of any mega breakthroughs for some time.

Turnout for our Wednesday night digging sessions remains at an all time high, usually getting 10-12 people turning out, spurred on by the measureless caverns that must lie undiscovered under the southern Jurassic slopes of the North York Moors.

In fact, turnout has allowed us to continue to push three separate projects each night, with the teams meeting up at The Crown in Hutton-le-Hole, our caver pub, for chips and a few pints. This Wednesday night ritual started shortly after we discovered Excalibur in 2007 and continues as strong today, although the food has evolved from picked eggs and pickled chillis, to fancy sandwiches, leftover roast potatoes and Yorkshire puddings.

The project I have personally been focused on is Piss Pot (Pandemic Pot, in polite terms, and as it will appear on the survey), which lies about 200m downstream of Jenga Pot. This started life as a tiny sink in the middle of Hutton Beck, but a poke during 2020 quickly identified a significant rift and which some enlargement, this soon reached a second rift, beautifully water-worn and dropping to a depth of about 14m. Sadly, the bottom of this second rift proved elusive through 2020-2021, with a small inlet tube and an equally small outlet tube that you’d struggle to even roll a tennis ball along. Excitement was quickly pushed elsewhere, to Cawthorn, and the continued digs in the Jenga Covid Extensions. Piss Pot was promptly forgotten about, all except a few efforts to make the entrance safe and floodproof, something we are pretty proficient at now.

This year has brought some renewed enthusiasm here. We decided to push the tiny onward leading passage. It is barely a conduit, but it does draught, and it does take water. Usefully, the limestone here is even crappier quality than usual for the North York Moors, almost chalk-like in softness in places. Our generator was quickly relocated to the site, and an armoured cable installed down the dig. We have become quite used to having electricity at our digs these days! This enabled us to run a 110V ‘Breaker’ (SDS Max drill with chisel function) with a meaty chisel. This melts through the limestone like butter, an entertaining and highly satisfying experience indeed. All other forms of enlargement (e.g. caps) achieved very little in the soft rock.

Within a month the ongoing conduit had quickly developed into a crawling height passage. Making it larger was like carving a pumpkin, and good fun, although it required ear plugs and a dust mask, as the dust generated is extremely high in silica, which is not good for lungs.

With the ongoing passage mined to 2m long, the ‘natural’ continuation became more football sized, and a bucket of water tipped down it flowed off nicely and made a satisfying splashy noise as it cascaded into a slightly echoey space ahead. This was most pleasing.

Through April and May we mined away, until, at the end of May, we were able to see into what looked like a natural, open new rift a metre ahead. It echoed, the outbound draught was really good, and excitement escalated to the point of weekend digging sessions too. On the weekend of 15th June, we had enlarged it just enough that we reckoned we could send a thinman in, and Toby Buxton was bribed with the offer of dinner to come and have a go. Of course, we could have just been patient and waited a few weeks, but we just couldn’t help ourselves. Toby earned his dinner by squeezing into the new rift, a tight experience indeed, to an enlargement where he could stand up. The new rift headed up several metres (possibly close to the surface) and the floor level here drops 1m to the ‘chert band’ which we know is ‘passage level’. A passage could be seen continuing at floor level, now basketball sized and looking very tempting.

We captured a bit of video footage, but as is traditional with ‘over-enthusiastic, pre-breakthrough’ video footage, it is fairly poor quality, rather hard to make out what is going on, or to get a sense of scale (listen with sound), but it does give a glimpse of the ongoing passage.


Over the last few weeks, we have mined the opening into the new rift larger, and last Wednesday I got in for the first time. The onward passage is looking good, although with a lot more mining to do, and we are encouraged by the fact that this passage continues to enlarge, and it puts out a stonking draught. The limestone here has improved in quality too, making it more amenable to more conventional passage enlargement techniques.

Hopes are high. This dig is at least 200m from the nearest passage in Jenga Pot, and potentially the start of another extensive inlet series into the system.

Separately, a team have been pushing a project called Mutton Butty, a dig we started about a decade ago and have returned to now and again, usually when we have had nothing better to be doing. This sits at the highest point on the limestone at the very top of the valley, 1.3km east of Excalibur Pot. This is essentially a completely mud choked, water worn shaft sat in a hedgerow between two fields. Sporadically, over the last decade we have mined this to over 10m deep, with occasional voids and a faint whisp of a draught every now and again. What offers the most hope here is the local stories of lost caverns around Appleton le Moors, apparently sizable stream passage once encountered, covered over and lost. Plus, this is a water-formed pothole, albeit a completely mud-filled one. It’s a tough dig to maintain enthusiasm with, but the potential rewards if this is an abandoned sink into a river passage, could be massive.

At Cawthorn, discussed in the posts above, work has continued enthusiastically, and only just a few weeks ago, the team arrived late to the pub beaming like cheshire cats, having got through some boulders to progress forward about 20m. Breakthroughs of this length in Cawthorn have been rare, with most boulder blockages leading to the next only 2m beyond. This must put the cave length at over 100m, still following the stream, still draughting and still with huge vertical and horizontal potential.

The challenge at Cawthorn is that we are not in the proper cave-forming limestone. We are in some crappy gritstone layer. It is obviously calcareous enough to form a phreatic passage, but not stable enough for the resulting passage to be self-supporting, hence we are mining along a sizable passage blocked entirely by the fractured contents of its own roof. Work is progressing using mainly plug-and-feathers (as the rock is really soft) and a few caps.

We are encouraged by this most recent breakthrough because it represents a significant amount of passage without a boulder blockage, and we hope that as we dip further beneath the surface (the passage is dipping significantly) we will get into some more stable rock further from the surface sinks, and unobstructed passage will start to predominate.

That’s a very long dig report from about 30m in total of new cave! Hopefully the next instalment will better justify the word-count!
 
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