Caine Hill Shaft - One of Britain’s Deepest Caves?

By Tony Jarratt

       “To some, digging is a fairly tedious chore, and they are only sustained by the hope of triumphs to come. To others the digging operation itself is fascinating. It is seldom simple.”

       Digging for Mendip Caves – W. I. Stanton – Studies in Speleology, Vol IV, 1983

Continued from BB 528. Photos by Sean Howe.

Further Digging 20/5/07 – 27/10/07

     Errata: The photo of “Dudley Herbert” on page 21 of BB 528 is actually of Mike Thompson.

     Robin Main of Priddy has confirmed that Caine Hill is the name of the steeply sloping field behind Manor Farm but has no idea of its derivation. A character met in the Queen Victoria Inn claims to have dug the foundations for the adjacent house and stated that the open hole found was not as big as we were led to believe.

     On the 20th May Trevor Hughes, Jane Clarke and the writer, assisted on the surface by Tim Andrews, Darryl Instrell and Bob Smith removed 64 loads of spoil and loaded Tim’s truck with over 1½ tons for disposal. Tim also donated another section of alloy ladder, which your scribe used next day to replace that on the entrance shaft – fixed to a shorter section. This was done as he had deepened this shaft and cleared clay from the ledges below to make a better bag stacking area. He hauled out 16 loads from here and then continued digging in Root 66. Tim later went to the end for a look and was suitably impressed. He was delighted that he now owns an actual cave as well as a mineshaft! 27 more loads came out on the 23rd when Jake Baynes, Paul Brock and the writer attended. The second pitch was re-rigged with an alloy builders’ ladder to ease bag hauling and digging was continued at Root 66. More work was done here, by your scribe on the 25th but the poor quality of the air drove him out after an hour. Conditions had improved on the following evening, possibly due to a change in atmospheric pressure, when he carried on with this project. On the 27th, despite atrocious weather, 55 loads were hauled out by Bob, Jane and the writer – all from Root 66 – and next day Jane, Bob and Hannah Bell stacked lots of clay on a convenient ledge ready for bagging and hauled 1 token load out. This clay was bagged on the 30th when digging continued at the end and 35 loads reached daylight; Henry Dawson, Bob and the writer making up the team. Several more small airspaces were revealed. Further digging and bag-filling was done here by your scribe on the 1st June and on the following day he concentrated on the dig in the main rift below Boxwork Passage where a tiny airspace was revealed on the NE side. A return was made next day when he cleared the remaining clay and a large rock step from the entrance shaft. 18 loads were hauled out. Another solo trip on the 4th June resulted in re-positioned entrance ladders, a scaffold bar and pulley on the second pitch, more digging below Boxwork Passage and 20 loads out – warm work in the prevailing fine weather. 50 more came out on the 6th when Hannah, Helen Stalker, Pete Hellier and your scribe cleared the cave – temporarily!

     Jake and the writer were back at the Boxwork dig on the 8th June when 19 bags were filled and hauled out and an arm-sized phreatic tube opened up on the SW side of the main rift. Next day the latter dug and filled bags at both sites. He returned on the 10th with Bob, Trev and Hannah to haul out 50 loads, some of these being freshly dug from both sites – where the diggers both got surprisingly cold. 1 token load came out on the 11th June when the writer concentrated on the Boxwork dig. A palm-sized slab of galena (lead sulphide PbS) 1-2 cms thick and weighing 800 grammes (1½ lbs) was disinterred from the clay floor indicating that the Old Men could well have been prospecting for this as well as ochre. Derived from a primary   hydrothermal vein deposit located many metres above the present land surface or from limestone dissolution around a minor “stringer” of ore, this residual, secondary galena has been smoothed and rounded during its downward progression from its original position – indicating the extreme age of the in-filled cave passage in which it was found (Barrington and Stanton, 1977, Stanton, 1991). A whitish coating may be cerrussite (lead carbonate PbCO3). Thick “veins” of sandstone-like rock in the walls of the rift here may be red-brown, silty mudstone, Triassic neptunian dykes formed from either seafloor or desert deposits which were washed or blown into open joints and fissures in the underlying bed rock and often associated on Mendip with primary mineralisation. Another airspace was revealed on the NE side with a void visible a couple of metres away but inaccessible without banging or chiselling. The airspace opened on the 2nd June connects with this so further removal of the clay floor was planned in the hope of entering it from below. Lots of bags were filled and stacked and even more added to the pile on the 12th ready for the Wednesday night team on the morrow. This turned out to be limited to Bob, Hannah and the writer but being of tough stuff they managed to load Tim’s truck two thirds full and haul out another 50 loads. 14 more came out on the 15th when Bob and your scribe continued digging in the floor. Further digging was done by the writer next day and on the 17th a strong team comprising Bob, Fiona Crozier, Trev, Duncan Butler and your scribe worked at both sites until poor air conditions drove them out after 55 loads had been removed. Bob came up with a name for the second drop – Son of a Pitch! A solo digging session by the writer next day was soon halted by the atrocious lack of oxygen but several bags were filled at the base of Son of a Pitch and 2 reached the surface. A walk around the field to the north on a quest for other mine workings revealed little of interest.

     New digger (and New Inn barman) Keith Creagh joined Jake and the writer on the 20th when the air was improved by the use of the vacuum cleaner to allow further digging in the pitch floor and the removal of 23 loads. Two days later the vacuum cleaner pipe was replaced with a longer length of greater diameter giving plenty of spare at Root 66. Here Fiona filled nine bags and used a valve and 1.5 litre bottle of compressed air to avoid the unpleasantly claustrophobic effects of the poor air conditions. The bag supply was kindly donated by interested villager Mark Glover. Meanwhile the writer filled lots more bags at the base of the ever-descending Son of a Pitch – having no bad air problems. The duo returned to their respective digs on the 24th in relatively excellent air conditions. Thanks to the timely arrival on the surface of Steve Woolven and Gary Cullen the total hauled out today was 47 loads. The atmosphere was much poorer next day when your scribe dug at both sites and removed 4 loads but when he returned with Fiona on the 26th conditions had dramatically improved and both sites were dug further. 1 load came out – the rock on which the first section of the entrance ladder was perched and erroneously thought to have been holding up the ginging! On the 27th the air was again poor but Hannah, Bob, Jake, Keith and your scribe dug a little at Son of a Pitch and removed 50 loads. Tim helped load up his truck with a ton or so of clay and the team accompanied him to the, as yet unseen, spoil dump where they were relieved to find that there is ample space for another 1,000+ tons. Unfortunately, in the fullness of time it will all get washed down Swildon’s!

     Solo digging becoming popular, Fiona did a stint at Root 66 on the 28th June and stacked about ten bags. She filled   another six on the following evening while the writer dug and drilled at Son of a Pitch.  A small, fragile lump of mineral weighing 340 grammes (12 ounces) was recovered from the clay floor. This was identified by Nick Richards as goethite (brown hematite – Fe3+O), an iron oxide associated with limonite (yellow ochre) and derived from the degradation of iron pyrites. Like the galena this is a residual deposit that has worked its way downwards from the primary veins way above. He also explained that the, sometimes powdery surface of the cave walls indicates that some of the limestone has been transformed to dolomite. More digging was done here by the writer on the 30th June and next day he returned with Fiona, Duncan, Trev, Bob, Helen Brook (S.W.C.C. – now also B.E.C.), Jinni King (Cardiff U.C.C.) and Kate Humphries (C.U.C.C.) to haul out 56 loads and continue digging at both sites. A passable route was dug to connect the bottom of Son of a Pitch with the continuation of the main rift and a small cord charge was fired in an attempt to gain access to the void in the NE wall near the base of the pitch. On a solo trip next day the writer was delighted to find that the bang had done a surprisingly good job and produced a vast amount of broken rock. Another bang was required to reach the void but air conditions did not encourage a lengthy stay today. Wednesday 4th July saw 7 bags out, mainly filled with bang debris. Hannah and Bob both put up with unpleasant fumes lingering at the top of Son of a Pitch while below, in more pleasant conditions, your scribe laid another charge. This was ready just as Sean Howe arrived – for a very short trip – before the bang was fired.

     The writer returned on the 6th intending to fire up the vacuum but Tim was at Priddy Folk Fayre so he nipped down to check the air and was amazed to find it good. More bang spoil was removed and another two shot-hole charge fired. The novelty tonight was the sound of live folk music heard from the dig face! Assisted by Bob your scribe cleared the spoil on the following evening and placed yet another two shot-hole charge. After firing, the duo savoured the delights of the appropriately named Potholer bitter at a very conveniently located marquee. The air was then left to clear for a few days and on the 11th July the writer filled and stacked bags at the banged bedding where it was now possible to crawl in and look down a small rift to the north. Suffering from a cold and with the air tasting unpleasantly metallic he clambered out to meet latecomers John Noble and Paul. The former went for a brief look around while the latter hurled obscenities from above. Not a particularly productive Wednesday evening!

     The next visit was on the 14th when your scribe drilled one shot-hole at Son of a Pitch and filled bags at Root 66. Next day he and Trev continued work here and on the 16th he was back with John. More bags were filled and stacked and another two shot-holes drilled but the air was atrocious so they persevered and hauled 24 loads to surface before retiring – leaving the vacuum cleaner running to refresh the place. This worked well and on the 18th July Fiona and your scribe enjoyed the conditions while filling bags at both sites. A charge was fired at Son of a Pitch and a token 2 loads reached the surface. A brief visit was made by the writer on the 21st when the air was found to be good enough to clear some of the bang-debris and next day Trev continued with this while Fiona dug at Root 66 and Duncan enlarged the connecting rift between the two sites. Your scribe acted as bag hauler for the three diggers. The worsening air quality and bang fumes released from the mud eventually stopped play but not before 50 loads went out. Another 30 reached the surface next day when John finally cleared the blasted rock and the writer dug at the other two sites. This was only possible because of the use of the vacuum cleaner and it was actually far more pleasant underground than on the monsoon-drenched surface. Another 23 loads came out on the 25th when all three sites were dug by your scribe and Henry D. arrived in time to struggle with the full bags after pioneering the use of the vacuum hose as a speaking tube! 1 load – a phreatically sculpted rock flake – came out on the 28th when the writer filled bags at Root 66, partly with vivid orange ochre. 34 loads came out next day when Paul and Fiona dug at Root 66, Jane and your scribe continued clearing the connecting rift and Nicks Harding and Richards hauled from the surface with the latter briefly studying the geology of the cave in preparation for another visit on a less hectic occasion. Bob assisted on the surface due to alcohol-induced cracked ribs – the second team member whose underground exploits were curtailed by over zealous cycling!

     Root 66 was dug again on the 30th July by enthusiastic new digger, Sissel Balomatis (Cheddar C.C.) and the writer. 21 loads were hauled out and a two shot-hole charge was fired in the dig just above the floor of Son of a Pitch. Much of the bang-debris was cleared by Siss and Paul on the 1st August when they also assisted Jake, John and your scribe to load over three tons of spoil into Tim’s truck which he took away to the dump. On the 3rd the writer filled thirteen bags at Root 66. He was back on the 5th with Fiona when much digging took place here and 18 loads came out. A solo visit next day saw more digging and rock removal at the same site. Mike Willett joined the team on the 8th and dug at Root 66 while Helen S. and your scribe shifted bags, 48 coming out in total. A power cut stopped the vacuum cleaner for a while and later, in the Hunters’ the culprit was revealed as a local who had chain-sawed a tree branch which, dropping on to the cable severed the village electric supply. He wishes to remain anonymous so we will call him “J.C.B”.

     On the 9th Tony Audsley commenced work on pointing the entrance ginging in preparation for the replacement of the rusting Acro-prop with a permanent lintel. He noted possible traces of original lime mortar. Some token digging was done by your scribe in Root 66 on the 11th and next day he returned with Duncan and Ray Deasy (on his annual visit from Australia) to continue with this until stopped by an apparent rock pillar in the middle of the passage. Duncan concentrated on enlarging the bottom of the main rift. On the 13th Tony continued fettling the entrance shaft while the writer laid a five shot-hole charge in Root 66. After firing this the duo retired for lunch then returned to continue with their projects. The morning’s bang had done a good job so a two shot-hole charge was fired to enlarge the squeeze from the main rift into Root 66. A total of 6 bags of spoil came out today. The spoil from the banged squeeze was cleared on the 15th  by Mike, Helen, Jeff Price and the writer when a total of 34 bags and skips reached the surface. The bang had brought down a vast amount of rock - far more than it should have - indicating that the roof here was potentially unstable and

that blowing it down had been a wise move! Two days later the writer bagged up much of the spoil from the bang at the end and this was hauled halfway out on the 20th, when he was joined by Jeff. 12 loads came out today, mainly rock and clay cleared from the banged squeeze. Tony measured up the entrance shaft. On the 22nd August the banged squeeze was finally cleared by your scribe when a possible way on behind clay infill was revealed to close down. Mike continued digging at the end of Root 66 and Bob took CO2 samples with an expensive electronic gadget. He recorded percentages of 0.5 at the bottom  of the entrance shaft, 1.3 – 1.6 near the banged squeeze and 2.34 at the Root 66 dig. A flame safety lamp used in conjunction dimmed as he descended the cave and expired at the banged squeeze. He was only able to re-light it on the surface. 16 loads were hauled out and many more left for future removal.

      2 loads of spoil from Tony’s ginging repair project came out on the 27th August when he prepared the entrance shaft for the casting of the concrete lintel. Meanwhile the writer cleared the terminal Root 66 dig and laid a four shot-hole charge. Unfortunately this misfired so was left for a day as a precaution. Being a bank holiday there was a plentiful surface support team of Rich Witcombe, Paul Weston and the two Nicks. The charge was rewired on the 28th but again failed to fire – as it did twice more next day when all connections were changed and the firing cable tested. Even Tim’s lawnmower battery was tried in vain and your scribe, baffled, gave up the attempt preferring to return on the 30th with a fresh detonator and length of cord to join the two sets of double shot-holes. This thankfully did the business and on the 2nd September Trev and the writer bagged up lots of spoil and moved full bags towards the entrance. 1 load came out. Tony continued with his entrance fettling next day and drilled the “solid” walls while your scribe got rid of much of the blasted rock dumped on the surface by adding it to the drystone wall across the road and bringing it up towards its original height. Root 66 saw action again on the 5th when Mike and the writer filled bags at the end and, aided by Jeff, hauled 35 out. A clay-filled and easily diggable phreatic tube was opened up beyond the banged section and hope was restored. On the 8th September the writer filled and stacked lots of bags here until the air went stale. Digging did not reveal the ceiling of the tube thus ensuring that it was pleasantly spacious. “Free diving” was almost necessary to regain the surface through the hordes of mosquitoes now infesting the main rift! Next day he returned with John to continue digging and hauling. 53 loads came out. Bob and Jane briefly assisted on the surface. The two returned next morning and pushed on into the phreatic passage – now almost of kneeling height. John poked upwards with a crowbar to reveal a phreatic ceiling and your scribe then went in for a look. A lip of ochreous clay was pulled down to reveal a lengthy and (allegedly) draughting airspace. Jane arrived to fill more bags and confirm the draught. Tony, assisted by Paul, continued with lintel preparations and Rich professionally repaired more of Robin Main’s drystone wall opposite Tim’s house – an excellent PR job. They continued with these projects in the afternoon whilst the writer filled more bags at the end and decided that the dig now looked more promising than ever before and almost certain to yield significant cave.

     Tony spent six hours working in the entrance shaft on the 11th September, assisted from the surface by Alice Audsley. He constructed a timber former, intending to install this at a future date. On the 12th Mike and your scribe continued with the magnificently easy dig at the end and, assisted by Jeff, Pete, and Tim Ball on the surface, hauled out a total of 60 loads. Mike was perplexed by the disembodied voice of Tim issuing from the vacuum pipe, as it appeared to emanate from a blank rock wall! More bag-filling was done by the writer next day and on the 14th  Tony continued fettling the shaft while Tim Andrews went almost to the end to check on progress. The following day Mike moved all the full bags to Son of a Pitch and filled another eleven before poor air stopped play. In the evening the writer, Henry D. and Barry Lawton filled a few more bags at the working face and then hauled out 74 loads, clearing the cave. Life was much improved by the use of an electric leaf blower provided by Tim A. to blast fresh air down the vacuum hose. The 16th saw your scribe, Duncan, Barry and Bob removing 26 loads – all freshly dug from the end. Two shot-holes were drilled in the side passage just above the floor of Son of a Pitch. Two more were drilled next day when the writer and Henry Bennett dug at the end and brought out 4 loads. Tony laboured in the entrance shaft and on the surface to complete the lintel framework and could be heard, as if above, from the end of Root 66. Mike, Jane and your scribe were back at the working face on the 19th to dig and haul bags and the following evening the latter banged the four outstanding shot-holes, Judy Andrews actually firing the charge. He returned to clear these on the 24th but was not encouraged by the tiny way on so continued digging at the end. The almost 2m high passage here transpired to be a choked roof joint with the main phreatic tube continuing at the same level below – good news. He was joined on the surface by Tony whose open-topped Land Rover was commissioned to deliver a rigid steel ladder from the Belfry.

On the morning of 26th September Tony washed down the entrance shaft walls, getting soaked in the process and later Mike and the writer hauled 22 loads out, moved full bags towards the entrance and filled many more at Root 66. Phil Coles arrived providentially at knocking off time and was impressed with the progress made since his last visit. Three shot-holes were drilled in the walls of the main rift as the commencement of a project to create a skipway between Root 66 and Son of a Pitch. Study of the geological map indicated that the cave is south of the Priddy Fault and running parallel in the direction of Cowsh Aven Series in Swildon’s Hole to the east. The estimated depth puts the current end of the cave almost at the level of Swildon’s / Priddy Green Sink entrances - indicating that a connection with this system is more likely than the hoped for breakthrough into ancient fossil passages heading towards Cheddar. Rich has suggested that the phreatic Tubledown dig on the western side of the Swildon’s Five streamway may be a possible contender. A link would add 15 metres to Swildon’s current depth resulting in a system 169 m (554.49 ft) deep and a connection to Wookey Hole would make the total depth, at the present state of exploration, some 279 m (915.39 ft)  – one of the deepest in Britain; the Wigmore Swallet – Gough’s Cave potential being 296.4 m (972.4 ft) . Time and hard work will tell but it’s nice to know that B.E.C. explorers are heavily involved with both! Ogof Ffynnon Ddu, incidentally, is at least 308 m (1010.55 ft) and will probably forever be Number One. At least one cave in northern England has similar potential to the Mendip systems but the writer has no information on this to hand.

     More digging took place at the end on the 30th when Trev and your scribe also moved full bags towards the surface. Tony and Pierre Abastado (Marseilles via Estonia) then arrived and the rest of the afternoon was devoted to transporting all the full bags on the surface to the spoil dump, utilising both available Land Rovers – an estimated six tons! On the following day your scribe filled more bags at the end and drilled three more shot-holes in the main rift, which were later charged with cord and fired by Pierre (as a recompense for Waterloo). Tony, assisted by Pierre and Alice and Rosie Audsley laboured to install the lintel shuttering in the entrance shaft. Further work was aborted due to a duff cement mixer. Weather conditions were atrocious but 10 loads came out today. The writer also surveyed the cave resulting in a current length of 22.90 metres and depth of 12.41 metres. Tony and his team returned next day in better conditions and with a working cement mixer and successfully constructed the lintel with a bag of cement and five bags of ½” to dust. He was back on the 5th to reduce the shuttering. On the 7th October 33 loads came out courtesy of Trev, Carole White and the writer. One detonator from the last bang had misfired but the problem was resolved by Trev. Lots of B.E.C. dinner survivors visited but failed to dirty their hands! Your scribe and Carole were back next day to take a Land Rover load of bags to the dump, clear the latest bang spoil and drag bags around the cave until driven out by residual fumes. More lintel work was done by Tony next day - a magnificent construction bearing the inscription BEC 2007, above which is a Scandinavian runic carving doubtless intended to curry favour with the gods of the cave (or it could be a sort of mason’s mark!). A drag tray was installed in the widened main rift on the 10th and Carole, Mike, Jake, Phil and the writer hauled 60 loads to surface, most of which were dumped by Land Rover on the following evening. On the 12th your scribe returned to widen the skip-way, shift bags and dig at the end but was a little dismayed to find the terminal passage trending to the right (south east) and indicating that the way on may be in the floor. On the 14th, accompanied by Trev, he moved bags throughout the cave.43 loads reached the surface. 2 more came out on the 15th when the writer filled lots more at the end and took a Land Rover load to the dump. The 17th October saw Mike, Siss, Paul, Sean, Pete and your scribe moving bags throughout the cave and Phil and Jake hauling 90 loads to the surface in a magnificent team effort. Some digging was done at the end. Jane and your scribe filled more bags here on the19th and reached a smooth limestone floor. All full bags on the surface were dumped. The writer returned next day to fill many bags and reveal much more of the floor. When finally cleared this will give the passage a superb cross section. 

     On the 21st October Trev (as a birthday treat) and the writer hauled bags throughout the cave and attempted to break up a large rock obstructing the south-easterly way on but decided that bang was needed. This was done by your scribe next day after lots more bags had been filled. More bag-hauling was done on the 24th by Mike and the writer. 22 loads came out and the bang debris was cleared to reveal the passage seeming to turn to the left beyond the site of the late rock and following the general trend east-north-east. The latter filled more bags here next day and on the 26th and 27th he was back continuing this work. Vast amounts of ochreous clay need to come out but plenty of small airspaces are encouraging and there is no shortage of room in this stunningly pleasant and easy dig.

Thanks are due to Henry Bennett and Madphil Rowsell for computing the survey figures.

References:

     BARRINGTON, N. and STANTON, W. I.    1977.  Mendip, the Complete Caves and a View of the Hills. Pp. 228-229.

     STANTON, W. I.      1991.  The habitat and origin of lead ore in Grebe Swallet Mine, Charterhouse-on-Mendip, Somerset     Proc. Univ. Bristol Spelaeol. Soc., 19 (1), pp 43-65.

To be continued in BB 530.