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Atlas Aven

By Andy Sparrow

Most club members will be familiar with Thrupe Lane Swallet and in particular the head of Atlas Pot. Here the youthful and meandering Marble streamway cascades down into the spray filled gloom of the huge shaft.  The eye is drawn first to the gulf below and then into the greater blackness above; the magnificent, towering, Atlas Aven. Seventeen years have elapsed since the first cavers lights shone up, searching vainly for a roof.  It remains unclimbed.

The Marble streamway is only one (and the lowest) of three windows into Atlas Shaft.  By turning left at the start of the streamway a high rift (Bypass Aven) is entered followed by a boulder ruckle beyond which is the roomy Bypass Passage.  Bypass Passage emerges into Atlas about 30 feet above the stream inlet.  Easily missed is a hole in the roof leading up into Vengeance Passage and another, higher window into the shaft.  I first looked out from here on a trip last spring and noted a solid rock wall (ideal for bolting) bordering the left hand wall of the aven.

It was some months later that a friend, Steve Ellis, bought a cordless Bosch drill.  There are precious few unclimbed avens under Mendip to use such a tool; it had to be the big one - Atlas.  Before lugging the heavy drill and its waterproof carrying case down the cave we went to have a closer look at the view out from Vengeance Passage.  Two anchors were installed manually allowing me to tie on and lean out into the shaft and assess the potential.  Some 40 - 50 feet below the stream spewed noisily and endlessly into the void. Above, the Aven continued its unrelenting climb into darkness.  A detail 30 feet higher on the opposite wall caught my eye - the start of a tube? There was only one way to find out.

We took the drill down next time assisted by Steve's friend Pete and the process of bolting began. The route was dictated by the soundness of the rock and initially we worked horizontally along the wall to a small stance.  This was a perfect take-off for a descent of the huge shaft below and could not be resisted. On our next trip we placed two Petzl long life anchors for the big pitch, rigged the rope, and down I went. After a few feet the walls cut away leaving the rope in a huge void.  About 60 feet down a big ledge was reached below which the pitch became very wet; the end of the rope was clearly hanging some way off the floor.  Before prussiking back up I noticed a couple of 8mm anchors in the opposite wall that would provide a rebelay point, or perhaps with some care, a deviation.  The full length of the pitch is about 120 feet, making it the longest free hanging pitch on Mendip.  We called it 'The Space Walk'.

The next session on the 17th January coincided with the start of the Gulf War and inspired an appropriate name for the traverse out across the shaft - 'The Gulf Crisis'.  We began bolting upwards towards the tube. The drill made this a rapid and easy process and I was soon carefully free climbing the last few feet to our objective.  It was a goer.  Two anchors were placed in the roof of the tube and Steve joined me in 'The Vultures Nest' (situated 60 feet above a side passage called the Eagles Nest).

The muddy tube sloped down into an aven chamber with a floor of jammed boulders.  Between these rocks were ominous black holes which were soon confirmed to connect back to Atlas.  The Aven was climbed, past a mud choked tube, to where a small passage led off. Another way on from the chamber ascended a steep muddy slope into a distinctly phreatic area which looped back towards Atlas and entered a high narrow cross rift.  Time was short as our support team, Pete and Dave, were wet and cold (water levels in the cave were high and we all had a soaking; first at Cowsh Crawl and then under a torrential shower in Bypass Aven).  A couple of small leads were left for next time and we left the cave well pleased with about 60 feet/20 metres of new passage.

A week later we were back again.  The passage above the aven chamber was pushed for 15 feet before choking close to Atlas. The cross rift revealed a small, but perfectly formed, tube heading back towards Vengeance Passage.  This was too tight after 15 feet.  Our best find of the day was entered after a short dig from the chamber following the down dip continuation of the original tube.  Steve forced a tight section and followed an attractive 'Gothic' section tube steeply down for about 40 feet.  Hopes were high for a few minutes as the passage seemed to be leading us out of the known system into something older, but sadly the final choke was really final . We left the cave satisfied that reasonable conclusions had been reached with the remaining leads.  The Vultures Nest was finished with 100 feet + (30 metres +) of worthwhile passage.

But the project has hardly begun.  The finds so far are very encouraging; they represent old phreatic development predating Atlas and bisected by it.  The original Thrupe diggers speculated that an ancient route to Saint Andrew's Well could be found from the higher levels of Atlas; I hope by further work to prove them right.  Already we can see two more openings off the shaft that will be easily reached in the next month or so.

NOTE: For some months to come the traverse out across the shaft, the 'Gulf Crisis' will be permanently rigged.  This makes a descent of 'The Space Walk' very easy to rig; simply a case of clipping a rope into the two longlife hangers.  Be prepared to deviate or rebelay at the big ledge, halfway down.  Go for it - you will be impressed!