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The Mendip Invaision - Discoveries in the Rana Hole/Uamh an Claonaite System

Photo Jrat looking up from entrance of 2B's Chamber by Simon Bookes

This year’s Mendip Invasion of Assynt in NW Scotland was a poorly attended affair from the south with Paul Brock (B.E.C./G.S.G.), Anne Vanderplank (B.E.C./W.C.C.), Robin “Tav” Taviner (G.S.G.) and the writer making up the team. Tony Boycott and Tangent were unfortunately unable to join us but support came from Yorkshire (Dave Hodgson, Jamie Anderson, Norman Flux, Mark Brown and Anwen Burrows), Derbyshire (Nick Williams, Eddy Mason and Simon Brooks) and Edinburgh (Fraser Simpson, Roger Galloway, Annie Audsley and Ivan Young). Just before the Mendip team left more G.S.G. members turned up and surprise visitors Yvo Weidmann and his girlfriend Martina arrived from Switzerland. Yvo is a top European cave diver, surveyor, Meghalaya veteran and cave photographer whose work can readily be seen and appreciated in most, if not all, Speleo Projects calendars.

Paul and your scribe drove up on the 26th (well, Paul did) in eleven hours but this did include stops at the Black Isle Brewery for supplies and fish and chips in Ullapool. A session in the Alt Bar that night saw them not at their best next day and almost abandoning digging due to the glorious weather. Tav and Anne succumbed to this to ascend Arkle while the hungover ones eventually staggered up the Allt nan Uamh valley in the wake of Fraser, Yorkshire Dave and Jamie who were intent on completing the first diving through-trip from Claonaite to Rana. In the latter the Black Rift was rigged with ladders and the awkward traverses and knobbly crawls leading to Blue Chamber negotiated – Slipping Into Something More Comfortable (S.I.S.M.C.). After admiring the blue and crystal-clear static sump the duo crawled on into the 30m up-dip extension discovered by G.S.G. men Julian Walford and Martin Hayes on the 12th April. Here they admired pure white stalactites and helictites, mud formations and strange red crystals on the floor before looking for possible dig sites. Paul spotted the best option which was an almost vertical “bedding plane” filled with dodgy boulders to a height of about four metres to where a small black space hinted at open passage beyond. Each wielding a small crowbar they set about the choke at two places and easily disposed of tons of rocks with the aid of gravity and the roomy passage below. The writer was then able to push boulders into Paul’s dig from above and after about an hour and a half was able to traverse across the steep slope below even larger piles of “hanging death” to reach the black space. A squeeze upward and he was in more roomy passage and soon joined by Paul. Amazed at their easy victory the explorers realised that they were standing at the bottom of a huge and steeply sloping passage or chamber with a dry mud-covered breakdown floor. Now feeling much improved and almost bursting with excitement they scrambled up the 60 metres or so to the top of the chamber to find it over 30 metres wide at one point and with a central roof height of 5-6 metres. There were no formations but some impressive geological features which are well worthy of study by an expert. Near the top of the chamber, where huge breakdown slabs blocked any way on, a 20 m long passage was explored to a mud choke and a lower passage (later called Not Two B) and pushed by Paul for about 25 m, also led to a long term dig. Further down the chamber a descending side passage, later pushed by Annie Audsley, also ended at a diggable mud choke. A couple of other unpromising sites were also later noted. Totally gobsmacked the jubilant duo named the find “Two B’s Chamber” as it was Bigger and Better than two A’s Chamber – and was found by two lucky B.E.C. Bastards – and set off into the depths of Claonaite to meet the divers. They had just emerged from Sump 6b when the pair arrived and were also much pleased by their successful dive, though not looking forwards to dragging all their kit up through the generally vertical passages of Rana Hole. Fraser had to drive home but the other four later celebrated at the Inch. Paul was so embarrassed by today’s discovery that he at last joined the G.S.G!

Two B’s Chamber is probably the second largest in a Scottish limestone cave – with the possible exception of the partly sea-eroded main chamber of Smoo Cave, and has undoubtedly formed by roof collapse into the original phreatic bore tube heading through Blue Chamber and onwards to The Great Northern Time Machine – Scotland’s largest chamber – where it was joined by another phreatic bore tube coming in from Two A’s Chamber, Belh Aven and Portobello Promenade/Memories of Tangalle. Investigations above the Twin Falls of Jabaroo may reveal more breakdown passage running back up towards Blue Chamber. Without the fortuitous short phreatic tube dropping into Blue Chamber from the awkward S.I.S.M.C. this fine addition to the system would be inaccessible. Could this be a flood overflow conduit formed along a convenient joint after the main bore tube became blocked with glacial (?) deposits? Much more recently this passage was utilised by the Black Rift streams.

The discoverers were back down Rana next day along with Ivan, Annie and Roger and a survey was completed from Black Cuillin Chamber to the end, a total of 261 metres (new passage making up 166 metres of this) and showing that the end of the chamber is located in the limestone band to the east of Beinn an Fhuarain. The passage seems to be running roughly parallel with the Claonaite streamway some 150 metres further east. To inspire further celebration it was now realised that the system had been pushed to just over 3 kilometres – another Scottish record. Eddy, Nick, Tav and Anne had meanwhile been touring and looking at digging sites in Claonaite Seven.

For a change Campbell’s Cave was the focus of attention next day with Roger, Annie, Anne, Norman, Paul and the writer preparing the surface depression for a major onslaught. Stone steps were constructed, the spoil heap extended, the cave entrance area stabilised and a massive wall commenced in the stream channel. No forward progress was made but good weather made this tidying operation a pleasure.

Roger, Annie, and the writer were back down Rana next day but on a purely tourist trip to show Richard Mackenzie (the owner of the Inch) and his Dutch friends Jan and Joris Van den Berg the cave as far as the head of Black Rift. All thoroughly enjoyed it – especially 11 year old Joris - and were most impressed with the engineering. Roger started a dig in the higher reaches of Two A’s Chamber (to which he and Annie returned on the following day and declared a long term job).

Simon Brooks exiting Blue Chamber Sump (photo Paul Brock)

The 2nd May saw Norman continuing work on the Rana breakthrough-point dam while Tav, Paul and your scribe assisted Simon with his diving gear. Blue Chamber sump was the target but unfortunately after some 5 metres it was completely silted up. Simon then visited Two B’s Chamber where he took lots of photos with the writer for scale. Tav and Paul went to dig at a site above Sump 6b where a breakthrough was made after half an hour into some 50 metres of bedding passage with a dug (and horribly loose) connection to The Palatial Abode of Edward Concrete Head and thus a round trip of academic interest. It was named “Duelling Pianos”. The possibility still exists here of a by-pass to Sumps 4, 5 and 6b.

Your scribe, being fed up with the A.N.U.S. valley, walked from the G.S.G. cottage to the Abhainn a’ Chnocain area on the 3rd May. The partially blocked entrance of the 8 metre long Easter Bunny Cave was easily found and made accessible – if a trifle squalid - within 20 minutes. Half an hour of crowbar and entrenching tool work on the terminal collapse revealed a 2 metre extension and no possible chance of any more. At now 10 metres in length it can be thankfully ignored in the future. It was found by the writer and Helen Macpherson on 4th April 1980 and had been awaiting another visit since then! The entrance was partially refilled with peat, rocks, slime and an old bucket. Directions to its exact location can be found in the G.S.G. Hut Log should any masochistic grotthole connoisseurs be reading this. Back at Taig nam Famh a visit was had from a couple of Jehovah’s Witnesses but they were repulsed by Anwen who gave them a piece of her mind regarding their missionary zeal amongst perfectly happy tribal societies. Roger, Annie, Mark and Norman continued clearing the Skye-Way in Rana.

Other activities included hill-walking; dig investigation by Nick and Eddy in Traligill and levelling of the site for the store extension by capping and banging. The latter was particularly impressive as large chunks of shattered pallet landed on the cottage roof and debris rained from the skies following a 9 shothole charge of 12gm cord! Refreshment at the Inch, the Alt and back at Taig nam Famh was a suitable reward for the hard work regularly expended.    

A serious geological and geomorphological study now needs to be done on the Rana Hole/Uamh an Claonaite System. The huge lumps of broken stalagmite bosses at the top of Black Rift should surely be perfect for dating purposes and would give an indication as to when breakdown created Two A’s Chamber. They also indicate a much warmer climate with plenty of vegetation when they were formed. The high-grade survey of the system needs upgrading and perhaps re-surveying in Claonaite Seven, especially in the complicated area around Duelling Pianos. Tav has found a possible link dig to Otter Hole and there are many more sites of interest as shown by the above results. The southern contingent hope to return for the G.S.G. Annual Dinner in October when some of these sites will hopefully be investigated – if they have not already yielded by then!

Errata: Breakthroughs at Rana Hole, Assynt, Scotland - BB 529, p61, “Mark bolted up Belh Aven for some 20m…” Not 60m as stated.

By Tony Jarratt