Digging at Thrupe Swallet, or The Agony and the Ecstasy.
Part I: The Agony.

by Tony Audsley

Only the Agony is available at the moment, so we will start with that and just hope that the Ecstasy will come later.

Thrupe Swallet (NGR 60574583) lies on the Thrupe Fault and is a pleasantly wooded depression wherein a modest spring fed stream sinks near the base of a 17 foot high cliff.  The site is about three hundred yards east-north-east of Thrupe Lane Swallet and is being dug by an odd collection of bods (BEC, MNRC, WCC) with a soft core of ageing ATLAS members.

The nature of the dig

Thrupe Swallet is governed by the Thrupe Fault.  Underground, this appears as an inclined rockface, dipping at about sixty degrees to the horizontal.  Under this slab is a jumble of boulders and gravels with a mass of clays underneath. This mess has tended to slide downhill, but has jammed every so often against the rock roof.  This has given rise to a series of voids or 'chambers' as shown in the diagram, with blockages between.

The voids are not chambers in the conventional sense of the word, but merely open spaces within the boulders. The first three digs on the site remained entirely within this zone of boulders and voids and did not enter solid rock at any stage.

History

Thrupe Swallet has been dug on three previous occasions.  Firstly by Gerard Platten and the Mendip Exploration Society from October 1936 until December of the same year.  An early reference to the digging can be found in Gerard Platten's Scrapbook:-

"We have now enlarged the entrance until it is fully 5 ft. across; it drops steeply for 6 ft. under a solid limestone slab into a chamber about 6 ft. across in which you can in one spot stand upright.  The roof is a pile of boulders but very safe ..... The floor is loose cave earth and stones, amongst which I found the tusk of either a wild boar or cave lion about 3 inches long". (See fig 1). (1)

Gerard Platten's sketch of the first dig at Thrupe Swallet.

Unfortunately, the cave lion turned out to be pig and the "very safe" roof turned out to be a mass of rubble.  By November, the diggers were concerned about the stability and safety of the dig. Despite this, they managed to penetrate through the boulders to a depth of 30 feet.  Their efforts were brought to an end by a near fatal incident:-

"As the last member of the digging team was crawling out through the small entrance chamber, the ceiling - which consisted of a large rock - subsided and would have completely settled down; had not the head of the pick axe which the member was carrying prevented it.  He was held firmly between the floor and the ceiling in the space separated by the points of the pickaxe." (2)

Fortunately the digger was extracted without serious injury, but the rescue left the entrance in a chaotic state and the incident had unnerved the team, who decided to abandon the site.  After all, at that time, there were many prime sites still to be dug.  Thrupe could wait.

The second attempt on the cave occurred 22 years later.  Norman Tuck started digging there in May 1958 and he was joined by Dave Berry and George Pointing in 1959.  They found a boulder chamber and a promising hole leading down from this.  They had the usual difficulties with Thrupe boulders and found it difficult to maintain a team of diggers willing to have rocks fall on them at regular intervals.  The dig was reluctantly abandoned in the summer of 1960, having reached a depth of something like 30 feet.

In 1963, the Wessex, having finished working at Cow Hole, adopted Thrupe Swallet as their next official club dig and started work there during the August Bank Holiday of that year.  They sank a shaft at the base of the cliff, set up an ingenious system of winches and traverse lines to remove the spoil and built dams in an attempt to reduce the water flow underground.  This was surface digging in the grand style and deserved to succeed.  However, the diggers followed the stream, or perhaps the stream followed the diggers.  Either way, the dig was plagued with water.  This turned the underground fill into a mobile slurry which required extensive timber shoring to hold it in place.  Every so often, the dig's Deity in Residence, a playful being, dropped a rock on the diggers, for example:-

" ... whilst in the lower tunnel Denis Warburton had a large slab detach itself from the left hand wall and this tended to push him further down and, of course prevented his retreat.  Quick work by Richard West with a crow bar prevented the slab from completely blocking the tunnel and allowed Denis to scramble clear." (2)

By the summer of 1965, the diggers were becoming disheartened by the difficult conditions and in particular, by the lack of an obvious way on:-

"With only one solid rock surface and that at some 40 degrees dip, it gave the impression that the route being excavated had no particular significance, but that it was a large boulder and mud filled cavity with many possible routes by which the water could descend until it reached the limestone proper". (2)

So, they abandoned the dig and the site lay neglected.  Moss and ivy covered the spoil heaps and the traverse cable rusted amongst the brambles. The Deity slept on undisturbed for another 34 years.

The present dig

Sometime in the summer of 1999, none of the present diggers can remember the exact date, Dave Speed noticed that a collapse had occurred at the base of the cliff a few yards away from the site of the last Wessex shaft.  This looked distinctly promising, so ancient ATLAS members were brought out of cold storage, dusted down and set to work.  Over the next few weeks we sank a short but superbly unstable shaft down through the boulders.  It became apparent even to us that if we wanted to get any deeper, or for that matter any older, then something substantial in the way of shoring was required. On 5th December 1999, Jim Young and Dave Speed, aided by Dave Morrison and Simon Meade-King constructed a welded steel framework for the shaft.  This was our first serious work at the site and, because of the lack of any earlier known date, it is taken to be the official start of the dig. By the end of the year, the shaft was 12 feet deep, running down against the wall of the cliff.

Work continued on deepening the shaft and extending the steel shoring during the early part of 2000, with a couple of months break during April and May to avoid the lambing season.  After this break, when digging restarted on 14th June, the first task was to install the winch that had been brought over from Little Crapnell.

The winch increased the rate of digging very satisfyingly and within the next couple of sessions, we had reached the boulder chamber described by previous diggers.  This lay somewhat to the east of our shaft.  The stream entered this chamber through remains of the 1960s shoring jammed in the roof and disappeared in the floor down the blocked remains of their lower shaft.  We earmarked the chamber as possible dumping space, but otherwise we ignored it.

Returning to our shaft, at about 25 feet down, we encountered a small rift (initially about a foot wide, but narrowing to a few inches) running into the cliff face. There was a certain amount of discussion about this between the "go-into-the-wallers" and the "continue-on-downers".  However, the "continue-on-downers" won the day; at least their way was man-sized. So down through the boulders we went for another eight to ten feet and eventually uncovered a black hole in the floor. Rocks dropped down this could be heard rumbling away for fifteen feet or so, all very satisfying.

The author at the bottom of the entrance shaft.

At this point, fate, or possibly the Deity in Residence took a hand.  It was now September and the weather was VERY wet.  The marl fill at the base of the shaft softened, then flowed into the shaft like thin porridge.  The boulders above tumbled down to fill the void, putting some interesting twists in the steelwork in the process.  The Deity was obviously on the side of the "go-through-the-wallers".  It was time for another look at the little rift.

Poking about at the far end of the little rift with a long iron bar dislodged a small cobble.  This fell a short distance, perhaps four or five feet and then landed with a distinct resonant thud.  There was a void ahead.  This finished the argument with the "continue-on-downers", so we backfilled part of the very bottom of the shaft, to support the steelwork, then concentrated on enlarging the little rift.  This came to be known as Salami Passage, because of the red and white mottled nature of the rock.

By the beginning of October, Salami Passage had been enlarged sufficiently to allow access to the glory thought to lie beyond.  This turned out to be a miserable, solidly choked "chamber".

Here it should be pointed out that anything in this dig which isn't actually a flat out crawl may be referred to as a chamber.  This gives an impression of spaciousness and magnificence, which is otherwise sadly lacking.

So, lowering the floor of this chamber revealed a small hole trending approximately south east.  This hole emitted A DISTINCT DRAUGHT. The log for the 22nd October reads:-

"A few feet of awkward progress along this tube was made, following a distinct draught and the sound of falling water".

It is at this point that, with hindsight, I now realise that the Deity is female and that then she was playing games with us.  Lying in that wretched tube we could feel a cold strong draught and hear the wonderful resonant sound of water ahead.  A few feet more and we would be in.  The dig was about to go.

Promises, promises

On 3rd December 2000, we broke through into a boulder chamber, Advent Chamber.  This contained an assortment of boulders, some large, some unstable, some both, but no way on, no big breakthrough.  On the east side of the chamber, accessible via a low stoop was a small rift chamber about eight feet long by three feet wide, which looked like it might be useful as a dumping space (it was).  As for the way on, well, the lower end of Advent Chamber was a solid choke of boulders but it did at least look diggable.

One thing is interesting about the chamber.  Through a peep-hole in the west side can be seen a blackened portion of shoring timber, remains of the 1960s dig.  To get to Advent, we had dug our way into the cliff, then tunnelled through solid, and without realising it, gone over the top of the old dig to end up on the east side of it. In doing so we had found an open chamber just by the side of their dig. More importantly, we had now started on a route that avoided most of the stream so troublesome to the earlier diggers. Apart from a brief appearance of part of the water at the top of Advent chamber, it is largely dry - most of the water can be heard flowing away behind the west wall of the chamber, along the route of the old dig.  The Deity is fickle; sometimes she can be helpful.

This was the situation at the end of 2000.  72 digging trips in the year had increased the depth of the dig from twelve feet to fifty-five feet and given a passage length of 110 feet.

Wednesday 3rd January 2001 saw nine (yes nine!) people crammed into Advent Chamber, two of whom were able to do useful work.  The two workers secured a wobbly boulder and started on the drive down through the jumble of rock at the back of the chamber.  By the middle of January, this shaft was about 15 feet deep and we had entered the next chamber in the series (3 feet high about 4 feet wide, descending for about 10 feet at the usual 60ish degrees to the usual choke).  It was roofed as always by the hanging wall of the fault and floored with the usual mix of boulders, cobbles and stream debris. Work on the loose choke at the lower end of this chamber was going well, when in February the outbreak of Foot and Mouth disease brought caving and (nearly) all digging to a complete halt.

Bob Cottle in the shaft at the bottom of Advent Chamber.

By late July, we thought the foot and mouth outbreak appeared to be over, but were reluctant to start back just in case we were wrong.  However, a quite bizarre series of events led to the resumption of digging. It all started when, on the morning of Wednesday 25th July, a calf broke through the covering on the shaft and then fell down the shaft.

Before continuing, I should explain that at this stage of the dig, Salami Passage entered the cliff face about 6 feet above shaft bottom.  Furthermore, the bottom of Salami Passage projected into the shaft as a sort of funnel shaped balcony.

Luckily, for all our sakes, the calf did not fall onto the rock pile at the bottom of the shaft, but landed on the "balcony" and was scooped into Salami Passage.  It then slid about 8 feet along the passage and took a sharp right-hand bend followed by a 4 foot drop into the chamber beyond. By then, it had really got the exploration bug, for it then headed off towards Advent.  Fortunately, it couldn't make it through the squeeze and there it stuck.

At this stage in the proceedings no-one, with the possible exception of the calf itself, knew where it was.  It was just missing and its mother was raising the alarm by bellowing frantically. The diggers were called out just in case the calf had indeed fallen down the cave and a sharp-eyed digger went down the shaft to check.  As there was no sign of the calf at shaft bottom nor in Salami Passage, he reported, not unreasonably, that the calf was not in the cave.  He then went off.  Later however, the calf was heard calling from the cave and Bob Cowlin and his two sons started on the rescue.  They were joined sometime later by some of the diggers and the animal was hauled up the shaft.  Once on the surface, it succeeded in standing and then immediately staggered off to its mother and started to suckle.  Miraculously, its only injuries were two small cuts.  Now do you believe in the Deity in Residence?

The Cowlins were surprised and pleased by the outcome and were also justifiably proud of their own efforts, as none of them had ever been underground before.  On the condition that the top of the shaft was made secure, they kindly granted us permission to restart digging.

By the end of September, the shaft had a cattle-proof lid and by late October, Maglite Grotto, a low, sloping chamber some 15 feet long, 8 feet wide and up to a massive 4 feet high (in places) was entered.  This had a finely decorated but blind inlet passage, the Priests' Hole, coming in from the roof.  The rubble floor of Maglite Grotto funnelled down to a black pit where stones could be heard to rattle down for perhaps 10 feet more.

Maglite Grotto was a difficult place to dig.  The boulder floor rested on a foundation of stream debris and clays, lubricated into a mobile slurry by the water which now ran below the surface.  It was here that we began to experience the same sort of problems that must have bedevilled the 1960s diggers.  The whole area showed an alarming tendency to slurp downwards, despite repeated attempts to stabilise it by walling and shoring.  The digging was complicated by the presence of a large boulder, the "Hammerhead".  This boulder was critical to the stability of the whole area, but it effectively blocked the way on!  The digging became rather delicate and slow but, by 30th December, the pit was more or less stable and sufficiently enlarged to allow a view into the void beyond.  Yet another rubble slope ending in yet another choke could be seen.  Entry was left until the New Year.

By the end of 2002, there had been 37 digging trips (a low number because of the foot and mouth closures). The bottom of Maglite Chamber was at a depth of 90 feet and the dig had a total passage length of 233 feet.

Rob Taviner in the Maglite Grotto shaft.

Diggers and visitors (December 1999 - December 2001)

Annie Audsley, Adrian Bowen, Anthony Marsh, Bob Cottle, Clive North, Colin Rogers, Dave Everett, Dave Grosvenor, Dave Morrison, Dave Speed, Gary Sandys, James Marsh, James Witcombe, Jim Young, Kate Lawrence, Paul Stillman, Roger Marsh, Rob Taviner, Rich Witcombe, Simon Meade-King, Tony Audsley, Tony Littler.

References quoted

(1): W. J. Lawry, Report on Thrupe Pot. Gerard Platten Scrapbook. Vol XVII p4747 (Unpublished Mss., Wells Museum Library)

(2): Edmund J Mason. Thrupe Swallet, An Account of early work by the M.E.S. Belfry Bulletin No 199, September 1964 p3-4

(3): Alan J Surrall. Thrupe Diary. J Wessex Cave Club, No 107 Vol. 9 (July 1966)

Additional sources

The Hillgrove logbooks 1954-1963, WCC Journal, supplement to Volume VIII

The Mendip Caver 1(1), 1(4),2(3)

In the short term, more information can be found at:

Thrupe Lite http://freespace.virgin.net/t.audsley (now http://www.arcula.co.uk/thrupelite/ )

This website contains up to date information about the dig, lots of photographs, a few sounds and a certain amount of foolishness.  There is also a history section, where the references quoted here are reproduced in full.

Like everything on the web, the website will sooner or later vanish without trace.

Finally

"If more interest were taken in this dig, another Cuthbert's could well be the reward" .

Jim Giles. Caving Log. Belfry Bulletin No 157, March 1961, p2.

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