rfit pot – The Eastern Front

"I did not write half of what I saw, for I knew I would not be believed” — Marco Polo

Although I had only been involved in the very first reconnaissance digging trip, an early opportunity to visit the new find came in September 2013 on a pushing trip with Neil Pacey and Becka Lawson. The plan was to make a start on scaling an aven inlet just before the terminal choke, as well as clear up some loose ends on the survey. We got underground at around 10am and were soon at the duck just after the Mousetrap, in the connecting passage between Rift and Large. The duck had 4-5 inches of airspace which was a bit less than the others were expecting (I had not done it before so was in blissful ignorance). After this obstacle had been negotiated, we were soon past the bottom of Colossus pitch in Large and into the continuation of the main passage which ends at a slot down to a mud bank. That was as far as I had been, on the reconnaissance in February 2011. On this visit though, the mud bank was no longer there, instead a there was a huge pile of mud and rocks – a testament to the amount of hard work that had been put into this dig. I was invited to go first through the flooded crawl which had been named the Heffalump Trap. As a duck this is longer than the Mousetrap, but wider, and again had perhaps 4-5 inches airspace, rising to 6 inches in the second half. It also had a reassuringly strong draft.

Beyond here crawling through a pool leads to a slope up over shattered rock and into the fabled continuation of the main passage. I was suitably impressed! Immediately to the right is a short tunnel which leads to a 60m aven – the target of a separate bolting project. But the main way on leads through a series of fault chambers liberally strewn with large boulders. It ends with a hands and knees crawl past formations and a rather fine crystal pool, to the start of the Trenches. The entry to the Trenches is like crawling through cheese (crumbly Lancashire) but then the passage drops into an unpleasant mess of porridge (the Pig Trough). Fortunately there is solid floor about a foot underneath the squalor, which is sloppy and sticky as heck. The crawl then changes into a muddy hading rift which consumes much energy. Finally there is the proverbial slippery slope to get up, where the only usable footholds seem to be in the roof!

From here on it seems to me the cave changes character. Gone are the blocky chambers of earlier, to be replaced by wide low-arched roofs with sand/mud floors. I was wandering on in front at this point since Becka and Neil were tidying up some queries to do with the survey. The roof lifts and the passage becomes a phreatic tunnel of immense proportions (200m long, 5m high, and up to 18m wide) – it must be one of the largest in the Dales. It ends rather abruptly in a choke which is turned on the right, to be followed by more tedious flat out crawling. Where this enlarges, right leads to a dribbly inlet with a rope up it (a target of the preceeding trip). Straight on leads through a couple of walking-sized chambers and down to a final short crawl into the terminal chamber. Ahead is the terminal choke. On the left is the aven inlet which was bringing in about as much water as comes down Colossus pitch. The water runs forward to sink in mud and boulders at the base of the final boulder slope.

Whilst Becka and Neil were fettling gear I took a look at the terminal choke. It is a monster. The nearest things I have seen of a similar construction are the large chokes in the phreatic trunk routes in Ogof Draenen (eg, upstream end of White Arch Passage, downstream end of Big Country). These all seem to have been caused by faults and I guess the same is true here. On the far right of the choke is an obvious opening which I guess has been looked at but I did not investigate. Midway between this and the apex of the choke is a gap, penetrable by head and shoulders which could perhaps be enlarged with care to a possible continuation. The apex of the choke has wedged boulders above your head, jammed against the rising roof. Although there are intriguing black gaps there is not a sense of a strong draft. The left side of the choke is much looser and it appears to have been washed clean, either in floods or in the distant past. This side is much less hopeful. There are various ideas about what to do. The simplest would be to check out the lead at mid height on the right (with a crowbar, and good nerves). There has been an idea of using a turfer but I reckon you would need at least 30m of wire and a solid anchor on the side wall back in the chamber to do this safely.

Meanwhile Neil was making good progress with the bolting through the initial overhang, so I took some action shots. After about 8 bolts and one and a half batteries, he called it a day and rigged a static rope from a Y-hang. The next part looked less strenuous to a ledge, from which further upward progress looks considerably easier. We stripped the bolts and headed out. It was here that my lack of caving fitness generally showed itself, as the others left me for dust in the Rift Pot entrance series. I took my time, and reflected that the Eastern Front is an impressive, hard fought for, and well deserved discovery.

Notes

Exploration and surveying of the Eastern Front was undertaken by the Misty Mountain Mud Mining Corporation (MMMMC) – a loose collective of diggers from various clubs. At present the two aven series, both 50-60m, are still currently being pushed. The first aven series is tantalisingly close to North End Pot.

A tourist trip to the end and back will take 5-6 hours. The caving is a lot more strenuous than would appear from the survey. The easiest access is via Rift Pot -- this is currently (2014) rigged to facilitate exploration but beware that the ropes on the main pitch are of dubious vintage. It is also possible to gain access (or escape!) without using any gear, via the recent connection between Low Douk and the Kendal extensions. However this is not an easy option as it involves a lot of crawling in its own right.

The two ducks can be passed in relative comfort by floating through on one's back with a neoprene hood. The Mousetrap is notoriously unpredictable, whereas, so far as we know, the Heffalump Trap seems to drain reasonably quickly after wet weather out of the far side. If the Mousetrap duck is sumped, it can be bypassed by an alternative established by MMMMC in 2011. Heading from Rift, the Mousetrap bypass starts with a climb up through boulders about 6m before the duck itself. Heading from Large, it is less easy to find: one must first locate the 'sloping-floored chamber' mentioned in the Large (to Rift) description in Mike Cooper's book. From the sloping-floored chamber, the Mousetrap bypass is gained by a 3m climb up into a draughty inlet crawl in the roof.

The Ireby-Rift-Large phreatic trunk route is roughly parallel to, and about 450m NW of, the North Craven Fault. The terminal choke is at NGR SD 6862 7628 and has an altitude of 300m OD. This places it some 90-100m below the surface in a rather featureless area of limestone pavement known as Low Plain, not far from the Cheese Press stone. There are no obvious surface features. If extrapolated in a straight line, the phreatic trunk route would break surface after a further 670m somewhere around NGR SD 691 758, just to the left of the Kingsdale road where it starts to descend to enter the valley. Needless to say, there is not much to be seen there, and certainly not a gaping 18m wide x 5m high cave entrance which no-one had spotted before! Interestingly, surface field work by Dick Glover, recently verified by Steve Warren, suggests that the porcellaneous band lies at around 310m OD on Hunts Cross at NGR SD 689 759, but at around 285m OD in the vicinity of Valley Entrance.

The second photograph is from a combined photographic/pushing trip undertaken in March 2014 by Sam Allshorn, Becka Lawson, George North, Julia Arce Sáez, Paul Swire (Beardy), Jeff Wade, and myself.

Further reading

Mike Cooper's book Not for the Faint-Hearted describes the passages from the base of Colossus pitch in Large through to the Temple of Doom extensions in Rift. Mike also provides a brief history of the earlier explorations in Rift and Large, and a bibliography.

Descent 233, 16-18 (Aug 2013) describes the recent connection between Low Douk and the Kendal extensions in Rift Pot.

Descent 236, 19-22 (Feb 2014) contains a description of the discovery and exploration of the Eastern Front; Jeff Wade's excellent photographs from the 2014 photography trip can be seen in Descent 238.

The survex data set and the MMMMC master survey can be found at http://cave-registry.org.uk/.

Magic Map gives a useful web interface to the OS map data down to 1:10k, from which the above distances and grid references were estimated.

British Geological Survey map data shows the Craven Fault zone (zoom out to at least 1:50k and select the '1:50,000 Faults and other linear features' map layer). Further geological information can be found at Steve Warren's website.

Adapted from CPC Record 114, 5-9 (April 2014).

Copyright © (2014) Patrick B Warren and Craven Pothole Club Ltd.