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Tunnel Cave

Tunnel Cave Exploration 1953-62

By Peter I. W. Harvey                                                                                                                                            contents

The name ‘Dan yr Ogof’, meaning ‘below the cave’, originally referred to Dan yr Ogof farm, which was demolished to make way for the restaurant and other buildings connected with the showcave complex; the cave itself was originally known simply as ‘Yr Ogof’.  The river cave found by the Morgan brothers then took on the name of the farm and became ‘Dan yr Ogof’.  Just above the farm, in the vicinity of a small disused quarry, there was a small resurgence cave that was used as the water supply to the farm, the remaining water tumbling down the side of the small gorge to join the Afon Llynfell, the Dan yr Ogof river.

The resurgence cave was a low tunnel which went for perhaps 150ft and it was referred to as ‘Tunnel Cave’.  The entrance was about 3ft high and about the same width.  Across the entrance was a 2ft high brick dam, which brought about immediate immersion in cold water for any explorer who wanted to make sure that the description of the cave given him by others was correct.  A few feet further in, the roof dropped a bit and in wet weather the passage was completely blocked by water.  There was, however, a small leakage from the dam and in average weather the water was about 1ft deep with about 1ft of airspace.  The passage rose slowly after this, so that the depth of water decreased and further in there was another dam, not quite so high.  It eventually reached a small chamber in which one could just about stand up, with the way on completely blocked by boulders from which the small stream emerged.  Unsurprisingly, not many people visited this cave; getting soaking wet in cold water just to crawl in 150ft of very wet cave and see the boulder blockage at the end was not really worth the trouble or discomfort and, it being the water supply to the farm, cavers were not really very welcome anyway.

This was the situation until 1953 when Lewis Railton and Bill Little were having a chat with Ashford Price (senior) who mentioned that occasionally a strong draught blew out of the entrance of the cave.  Recent work in Ogof Ffynnon Ddu and Dan yr Ogof had shown how important draughts were in the exploration of new cave passages and so a number of people now became very interested in this wet little cave.  Among them were Edward Aslett, Bill Clarke, David Hunt, Clive Jones, John Truman and others.  It was convenient that about this time that the farm that had been using the water became vacant.

Before digging commenced in the cave, the mountainside above was examined in case there was an easier place to dig into the suspected extension of Tunnel Cave.  As nothing more promising was found, digging was started in the cave itself.

This was a difficult dig, as the way on appeared to be straight up through the boulders.  There was not much room in the little chamber, and no protection if the rockpile collapsed, so most of the work in removing boulders was carried out using small explosive charges.  Lewis Railton writes in the SWCC 10th Anniversary publication:

The use of hammers and crowbars was out of the question without running the risk of being crushed to pulp by the sudden collapse of the whole lot.  The job was done with small explosive charges placed in crannies between the smaller blocks.  The charges were fired from a safe but wet place back along the tunnel.  Most of the debris fell to the floor of the small chamber and loose and poised blocks were fished down with a piece of angle iron from an old bedstead, from the comparative safety of the low crawl with its solid roof.  The debris was then carefully removed and stacked in available places on either side.  The work proceeded over many weekends, always cold ones, so that there was an inwards draught to carry the smoke clear of the workers.  Soon it became necessary to bring in an 8ft or 9ft wooden ladder to get up to the working face as it was not safe to use the blocks in the boulder pile as footholds.  This made operations slower as the ladder had to be removed and stowed safely before every bang.  At last a narrow space, about 3 inches wide, was revealed between two big blocks and shining a light up it showed nothing but a black space beyond.  Whether it was big enough for a human being, we could not see.  This was encouraging but we dare not attempt to disturb two such big blocks so work continued forwards and upwards, as and how we could dislodge small blocks without, we hoped, disturbing the big ones.  Eventually, at the top of our ladder we had a sizeable shelf-cum-alcove.  It was between 3 and 4 pm on Sunday, Dec. 27th, 1953, the last day of the Xmas holiday, that John Truman went up the ladder to do some careful gardening of the loose debris.  After a short while he announced that he had a huge flat capstone above his head and a big flat topped block at his side with a space 8 inches high and 18 inches wide between them.  He called to us that he was going to try to get through, a tricky operation to get from a vertical to a horizontal position in his situation without double jointed knees.  The rest of us got well out of the way, held our breath, and hoped that nothing would shift - except John.  After a little muffled grunting John shouted that he was through and standing up.  I went through next followed by David Hunt and Edward Aslett.  All I could see was a wall about 5 feet away and a flat roof about 8 feet above a floor of large jumbled blocks; in every other direction was a wall of whiteish smoke, the product of our bangs.  I set off at right angles to the wall and in about 15 feet found another wall.  The others had swung off slightly to my left, while I swung right keeping close to the wall on my left.  While I was groping along in the smoke, a shout from the others indicated that the floor was sloping up to meet the roof their way and I called them to follow me.  After about 100 feet I had reached a floor of mainly fine, white gravel and in the thinning smoke the passage seemed huge, as indeed it was.  The others soon joined me to paddle along a shallow stream meandering between flat topped mud banks about 2 feet high.  We soon came to the end of the stream; it seeped out from the left hand wall. We went on up over a heap of boulders and down the other side to a stream flowing from right to left.  We had reached a T-junction with an even larger passage.  Here again was a mud bank liberally adorned with fine examples of ‘mud flowers’ formed by drips from the high roof.

On this first exploration, the group found that after 1000ft or so this huge passage reduced in size to more normal cave proportions, while towards the end the passage was 50-60ft high and 30-40ft wide it reduced to something like 10ft square or less, and after a short distance they came to a 10ft drop.  It was here that they decided to leave further exploration until the following weekend.

Davey Price's Hall, Tunnel Cave, now "Cathedral Cave"On the following Saturday we all went to the funeral of David Price.  He was buried in the little chapel, not far from the Gwyn, in the presence of a large group of his friends from the Swansea valley and the caving club.  He had been ‘Mine Host’ at the Gwyn Arms since cavers started to take an interest in Dan yr Ogof in the 1930s.  That evening and next day Tunnel Cave was explored.  The stream which flowed out of the cave was found to rise in a pool from the right hand wall.  This time there was no ‘banger’ smoke obscuring the view.  The passage increased in size and we found ourselves paddling up a small stream between mud banks, the passage size gradually increasing until towards the end it was 60ft high and about 40-50ft wide.  This enormous passage was named ‘Davey Price’s Hall’ in memory of the landlord we had known for so long.  The mud banks were covered with splash deposits, caused by constant drips from the roof, forming rose-like depressions in the mud, partially covered with calcite.  These formations were exceedingly interesting and were immediately taped off for their preservation.  Towards the end of the passage a stream of water fell from high up in the wall and in the floor were some fine cave pearls, a very rare form of calcite deposition.  Sadly, many floor features were lost in the subsequent conversion of Davey Price’s Hall into the show cave now known as ‘Cathedral Cave’.

After climbing round the small pitch where exploration had stopped on the first day, the passage was followed for several of hundred feet to a parting of the ways.  The left-hand branch developed into a meandering rift passage 20-30ft high and 2-4ft wide.  We found ourselves traversing at the top of this rift or half way up it but rarely at floor level.  About 2000ft later, after one or two ‘ups’ and ‘downs’, we crawled into a large chamber with a calcite slope going up to the left; this was ‘Cascade Aven’.  This steep slope was just climbable, going up for about 60ft. but normally a handline was found to be useful after the first person had climbed it.  At the top there was a delicate traverse and the cascade went up further again.  Exploration in this area, by Clive Jones and others, revealed a rabbit warren of small passages none of which developed into cave of any significance.                                                        back to the top

Others, who had examined the right-hand branch, found it to be smaller and more complicated.  One passage passed through a high aven – Steeple Aven - that appeared to have a passage at the top.  Another passage finished up in a pretty little chamber - Christmas Grotto.

Tunnel Cave was now nearly fully explored, except for the area around Cascade Aven and we did not know if there was anything at the top of Steeple Aven.  Climbing this aven presented a problem because the walls were smooth and vertical, about 80ft. high and too far apart to use the maypole in a series of steps from side to side.  The problem was solved by ‘Upit’, an 18ft steel ladder, in three sections with various brackets for attachment to the rock face via 1-inch rawlbolts drilled 10ft apart.  At the top of the ladder a bicycle seat was fixed and, sitting on this, another bolt hole could be drilled 10ft higher than the preceding bolt.  Using rope ladders and pulleys, the device could be unbolted, hauled up 10ft, and re-bolted to the two top bolts.  The idea was conceived by Bill Little, I put it on paper, and Lewis Railton had it made by Renold Tubes from high-tensile tubing.

It was in February 1955 that Upit was finally taken into Tunnel Cave.  It was just possible to manoeuvre the 6ft sections through the narrow passages into Steeple Aven.  Upit was assembled and set up against the sheer wall and the climb began.  Progress was pretty slow but, eventually, the opening 60ft up was reached.  Unfortunately this turned out to be only a shelf in the rock with a few boulders resting on it and a choked up rift behind.  This was a very disappointing result but there was the consolation that the equipment worked.  David Hunt was the hero of the day as it was he who drilled all the rawlbolt holes precariously mounted on top of ‘Upit’ despite the fact that the intended bicycle seat at the top for the driller to sit on was not ready!

Off a small chamber on the way to Cascade Aven, just past the 15ft pitch, a small opening at floor level had been entered, revealing a climb up some calcited boulders.  At the top, about 30ft up in an alcove on the side, was a small pool with a stream of water pouring into it and at the bottom there was a nest of cave pearls.  It was decided that these would probably be stolen if left unprotected, so a steel grille was cemented in position over the opening to the pool.  The first time I ‘saw’ these pearls was after the grille had been installed or, at least, I saw the grill, the cascade and the pool but it was so far behind the grille that I almost had to imagine the pearls!  The climb up to the pearls was quite hairy and on the way down I fell off.  Luckily I was on a lifeline and came to no harm

Over the years, there has been considerable interest in the small stream emerging in Davey Price’s Hall.  A few yards in, the water touches the roof and becomes a sump. There was not much water coming out in dry weather so Clive Jones and John Alexander decided that they could beat the flow by bailing with a couple of buckets.  In this they were fairly successful and managed to lower the level about a foot.  It was in June 1954 that Bill Clarke, during a dry spell when there was a small airspace, swam through the sump and discovered a further 120ft of passage terminating in another sump.  Later, on 5th September 1955, the bailers had another go and managed to lower the level 18ins.  This encouraged Glyn Thomas to build a petrol-electric pump and at Easter 1956 it was taken to the rising.  The first sump was pumped out but, although the level of the second sump was lowered 8ft, the limit of the pump, the sump was seen to be still going down.

It became obvious that the sump needed diving equipment and in March 1964 the first attempt to dive through this sump was made.  The divers were Bill Clarke and Charles George.  The water was very low on this occasion but no progress was made as they ran out of diving line.  On the 11th July, the same divers returned and Charles wrote in the SWCC Newsletter (No 49 March 1965):

This time an air space was reached after 150ft.  To the divers’ surprise it 'went'. Discarding his set and flippers, the job of securing the safety line assumed vast importance.  The fear of losing the end caused some terrific knots to be made.  The new passage climbed steadily from sump level and a small trickle flowed down to replenish the sump.  The passage was, on average, 6ft wide and 8ft high of keyhole section, the lower part being filled with shattered boulders.  The passage was well decorated with straws, light coloured stalactites, a few large columns of stal and some flowstone.  No draught could be detected but the air seemed fresh.  At about 350 ft from the sump an insecure block occupied part of the passage.  Being alone and cut off, it was considered unwise to go further.  The stand-by did not even know of the diver’s exit from the water.  The passage, however, appeared to go on somewhat reduced in size.  There were no obvious side passages and, without a compass, appeared to run in a northerly direction for over 350ft.  The passage had probably ascended some 60ft or so.

No further dives took place at this site even though there seems to be a slight possibility of exploring beyond the point at which Charles turned back.  This could be because over the next few years the divers were busy elsewhere in Ogof Ffynnon Ddu and Dan yr Ogof.

Anemone Passage, which was the high level passage with a stream of water pouring out of it at the end of Davey Price’s Hall, now received some attention.  Bill Little climbed up into it, but unfortunately there was no extensive system of cave passage to explore.    back to the top

It was not until August 1961 that SWCC started the final operation in connection with Tunnel Cave.  This was the drilling of a shaft down from the open mountain to the top of Cascade Aven.  It was thought that as the rift had been rising gradually all the way, the top of the Aven could not be many feet below the surface of the moor above.  It was decided that, if the depth below the surface could be established and was not too great, it would be worthwhile to dig a shaft into the top end of the cave.  This was where Bill Birchenough’s cave detecting machine was first brought into use.  The underground equipment consisted of a large coil, an oscillator and a battery, wired up to give out a magnetic signal.  The coil could be folded up for carrying into the cave and its 6ft diameter could be set up at the top of Cascade Aven.  The surface equipment was another smaller coil designed for receiving the underground signal.  This coil was wound on a wooden frame and was hand held so that it could be moved around in order to pick up the underground signal.  Both the position and the depth could be calculated.

On the day, the operation was successful and the signals were located giving an exact position on the surface and a depth of approximately 70ft.  This was quite close to the surface and was not an impossible dig as there was some least 20ft of air space above the inside coil’s position.

It was decided that a shaft would be dug into the cave from the point indicated by the detection device.  A start was made on the Whitsun holiday of 1961.  Excellent progress was made on the first two days and a depth of 10ft was achieved.  From here on, the rock became very much harder and digging became very difficult. The surface layers would have been affected by frost and rain and would tend to be easier.  Even some trials with shaped charges carried out by the SAS proved very disappointing, indicating that this was not the way forward.  The conclusion was reached that nothing but normal drilling and blasting would do the job.  The trouble was that SWCC did not have a compressor and drill.  After making many enquiries, Lionel Dingle, a member of the club, offered us the necessary equipment.  He drove the tractor-mounted compressor up the Swansea Valley to the Gwyn on the Friday of August Bank Holiday weekend in 1961.

Next day, of course, it was raining hard, as it often does in the Swansea Valley, especially when there is something on, and there was no chance of dragging the equipment up the mountain to the shaft.  Later on in the day, however, the rain eased off a bit and, with help of ropes and a large number of people, the tractor and compressor was dragged to the digging site.

Drilling started on the Sunday morning and, during the rest of the holiday, two rounds were fired, taking the shaft to about 20ft deep.  Each round consisted of 15 shotholes 4ft 6in deep for the central holes and 5ft 6in for those around the outside, each charged with a pound of Polar Ammon Gelignite.  Delay detonators were used in the outer holes.

It was disappointing that the weekend was spoilt by the weather and not so much drilling was achieved as could have been, but considerable progress had been made.  To obtain some encouragement, it was decided that an attempt would be made to see if contact could be made between the shaft and the top of Cascade Aven.  Anne Williams writes in the SWCC Newsletter (No.38, page 9):

It was the weekend following the bank holiday that one party went into the cave at dead of night, while another set off up the hillside.  It is a well known fact amongst members of the club that holes in the ground, even those as large as Pant Mawr, can move a considerable distance between visits.  Alan Stephens and I set off up the hill secure in the knowledge that we knew just where the hole had been left.  After a few mishaps in the dark we reached the point were we had left the shaft.  But, true to form, the wretched thing had wandered off a good 30yds, which was a long way at midnight in the rain.

It was decided that I should go down the hole first so, belaying the ladder to one of the tripod legs, I climbed down to sit at the bottom and tap on the rock with a stone at ten minute intervals.  I noticed that, even after a week, there was a strong smell of banger fumes.  We were prepared for a long wait and our surprise can be imagined when, in response to my first series of taps, barely an hour after the other party had gone in, I heard loud and clear taps in response.  We sat tapping through the rock to each other like a pair of demented woodpeckers for some time until Alan and I decided to call it a day.  The wood and nylon rope ladder gave us a few minutes of amusement on the way out, as I found that one had to climb up three rungs before the stretch in the nylon was taken up and one got clear of the floor.

The Party who went up to the aven was composed of Bill Birchenough, Eric Inson and John Dryden.  They must have travelled like those mythical beasts, ‘The Clappers’, to have reached the Cascades in well under the hour.

Discussing the trip afterwards, it was agreed that the shaft is in the right place to within a few feet and that the depth remaining to be dug is not too great.                                                        back to the top

So, we had a 20ft shaft but still no entrance.  Several efforts were made to carry on the work in 1962 but for one reason or another no real progress had been made.  Clive Jones writes in SWCC Newsletter No 42 (December 1962):

Two abortive attempts to get the Tunnel Cave shaft completed this summer had made those of us concerned with the project all the more determined on an all out effort some time before Christmas‘62.  The weekend of Dec. 8/9th was chosen, as the chances of dry weather are high at this time of the year.

The plan was as follows:-

1. The weekend of Dec 1/2nd would be spent getting all the heavy equipment, other than the compressor, up the hill to the site.  Lifting tackle would be erected and tested ready for December 8th

2 The compressor would be picked up from Cardiff or Swansea, depending on which one we could get.

3. A team of three or four persons would then be required on Friday afternoon to get the compressor up to the site and start drilling.  Eight vertical holes each 4ft deep and 1.375” diameter would be drilled round the edges of the floor and four holes of similar dimensions would be drilled on the diagonals to meet approximately under the centre of the shaft.  The central holes would each be charged with 1.25 lbs of ‘tree lifter’ and a No.0 delay detonator, the edge holes with 1 lb and a No 2 detonator.  All twelve holes would then be wired in series, so that when fired the centre would be blown out first and the sides blown into the cavity.

4. Whilst this was being done the Mountain Rescue Team would erect a 160lb mess tent for us near the site. (Not too near!)

5. The first round should be fired at 8 pm by which time there would be sufficient people at Penwyllt to man the lifting gear and haul out 3 to 4 tons of rubble.

6. Drilling would begin again on Saturday morning and blasting taking place at about 10 am.  A fresh team would then lift out the rubble ready for what should be the final round.

7. At about 3 pm on Saturday we should be probing with 6ft drill rods for the aven. Once located we would blast the top of the aven to the bottom of the aven.

8. Retire to the Gwyn Arms.

9. Spend Sunday getting the equipment back down the hill.

All very nice, but all very dependent on the weather.  The tackle was taken up and erected on December 1st and 2nd, and a swinging derrick, the pride of the engineering department, was erected over the shaft.  A telephone line was laid from the site down to the road.                                                        back to the top

The following Friday the compressor arrived and was taken up in Charles’ Landrover.  A second Landrover, belonging to Bill Clarke, brought up the rest of the gear.  The first round was fired at 8pm and the first clearing team started right away, finishing at 3.30am on Saturday.  The swinging derrick turned out to be ‘dodgy’ and was pulled down and replaced with a conventional tripod.  The mess tent had been erected as planned.  It was ‘all systems go’

The drilling team with Dingle were back on site at 8am and then our troubles started.  The first round had cracked the floor and this kept jamming the drill bit, so 2ft had to be chipped out and cleared.  A road breaker was brought up but by the time it arrived the job had been done by hand.  It was now 2pm and the weather all morning had been ‘bloody awful’.  Rain and wind had chilled everyone and goon suits were essential.  Water in the petrol kept stopping the compressor and when it was going it was using juice at the rate of 2 gallons per hour.  I must admit I was for calling the whole operation off, but everything was bogged down so we decided we might as well stay and carry on.

Drilling restarted at 3pm and at 6pm the second round was fired.  Repairing the shuttering and clearing the rubble took until 10pm.  Another team left the Gwyn Arms, half way through the 58th verse of the ‘Ball of Kirriemuir’ ready to chip out the bottom of the shaft and start drilling again.  The weather all through the night was worse than ever.  The compressor fuel system had to be taken apart and dried out.  It was 8 am before we were ready for drilling again.

By this time Bill Birchenough was biting his nails - we were 6ft from his maximum depth estimate.  The weather cleared and we started drilling again.  This time we were aiming for the top of the aven - we hoped.  The two foot rod went down without trouble and we changed to the 4ft.  The strata seemed kinder to the bit and we went down at a foot a minute.  The 4ft rod was changed for the 6 ft rod and we on our way down for the final count.

Five feet down we hit an air space.  Warm air came up the drill hole when the compressor was shut off.  A second 5ft hole was drilled a foot away from the first and this also went through.  The drilling was taken over by Dingle and Denis Bond and the final round was charged.  It didn’t go through to the aven but jammed.  However, we were through and it ought not to take long to clear the rest of the rubble.  The compressor and all the gear was loaded back onto the Landrovers and with the help of ropes and the aid of twenty or more helpers were got back down to the road.

The main work had now been completed, even though there had been no help from the atrocious weather.  The retreat from the mountain was quite an epic.  The heavy rain had made the ground very difficult for getting the heavily loaded Landrovers down the steep track.  The presence of something like twenty club members on the day, with ropes, made the difference between success and disaster, when the vehicles had to be manhandled over some of the worst places.

The hard work had now been done and all that remained was removing the rubble from the final charge.  This proved to be quite hard work as the spoil had jammed at the bottom of the shaft and had to be removed with crowbars whilst the diggers were securely lifelined in case the whole thing ran in.  The shaft was finally finished off with a locking steel lid to make it safe for animals and people walking the mountain.  There was now a fine through trip from the mountain entrance to the small hole in the valley near Dan yr Ogof.

Edited by Jem Rowland,                                                        back to the top
March 2009