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Backwater Aven
Report From: Ed.
Report Date: 11/09/2011.
Published: 11/09/2011.

History: In 1992 Dave Nixon and Shaun Puckering investigated the Backwater Choke in Speedwell Cavern. A small amount of digging was done at the time and it looked extremely promising, but with other projects in hand, the site was shelved for another day....

Friday 23rd July 2011: Nineteen years later that day arrived and DN and SP arrived back at the choke armed with some tools and supports. DN set about a boulder on the left hand side and within an hour there was a hole big enough to squeeze up through. Above was a chamber, all solid and secure, with the exception of one boulder above the breakthrough point which needed moving to make safe. Unfortunately, as it was moved it fell sideways into the hole blocking the connection with DN above and SP below. Twenty minutes of sledgehammer vs. boulder solved the problem. The chamber above took the form of a large ascending passage to a climb up over some large boulders into the base of a large aven, 6m wide, 10m long and estimated at 25m high. This is formed on a vein and contains a large amount of mineral, a bit of stal and a nest of cave pearls. The only way on was up. In all, this first day realised approximately 35m of new cave with an obvious way on.

Dave Nixon at the breakthrough point in the Backwater Choke.
Photo: Shaun Puckering. 11th August 2011
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Dave Nixon in the large passage ascending to Backwater Aven.
Photo: Shaun Puckering. 11th August 2011
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Dave Nixon in the large passage below Backwater Aven.
Photo: Shaun Puckering. 11th August 2011
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Backwater Aven.
Photo: Shaun Puckering. 11th August 2011
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Cave Pearls in Backwater Aven.
Photo: Shaun Puckering. 11th August 2011
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Saturday 6th August 2011: DN and Rob Hyland carried in ropes and climbing gear for a later trip and had intended to survey the passage discovered so far. Unfortunately the two parts of the electronic survey gear wouldn't connect so it would have to wait for another day. However, the highest visible point at the top of the Aven was measured at 23m.

Thursday 11th August 2011: DN and SP returned to climb the aven. DN led the climb in a single pitch over solid ground passing a small ledge and a dog leg topping out in a small passage approximately 30m up. SP joined DN to investigate the way on. Unfortunately, after just a few metres, the passage was blocked by a choke. However, it looked promising, there was an echo from beyond and a steady draught.

Armed and ready.
Photo: Shaun Puckering. 11th August 2011
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Backwater Aven from the ledge.
Photo: Shaun Puckering. 11th August 2011
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Friday 12th August 2011: DN and Simon Cundy returned to start work on the second choke, making good progress.

Friday 26th August 2011: DN returned with Keith Joule and a pile of scaffolding to continue work on the second choke. More boulders were broken and removed to expose the underside of a false floor, which soon gave way to open cave above. This took the form of a large ascending passage reaching the base of a blind dome after approximately 30m. A 6m climb reached another small choke providing the one and only lead. This will require further "engineering" to pass. This point is estimated to be around 50m above the Speedwell bedding. Work continues....

The second choke at the top of Backwater Aven.
Photo: Shaun Puckering. 11th August 2011
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Stripping the rock anchors from the climb.
Photo: Shaun Puckering. 11th August 2011
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Cave pearls.
Photo: Shaun Puckering. 11th August 2011
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Friday 16th September 2011: DN, KJ and SP returned to tackle the third choke. Initially it looked like it was going to be easy, but it soon became apparent that it wasn't. What looked like a collection of small to mid sized rocks loosely jumbled in an ascending passage soon turned out to be a collection of small to mid sized rocks made out of limestone with the characteristics of iron meteorites all glued together with a thin but impossibly strong film of flowstone. This resulted in little progress for a lot of effort. However, the way on looks good with a promising draught and a booming echo. A return with some appropriate tooling is planned.

Friday 23rd September 2011: DAN, SLP and KJ returned with armed with a selection of tools and although some progress was made it was hard won and very slow. However, the flowstone covered rocks that were causing most of the problem were removed and the choke beyond is much looser.

Cavers visiting Speedwell Cavern are asked to avoid everything above the base of the first aven until the chokes have been properly stabilised and the pitches properly rigged.
Thanks - The Backwater Aven Project.


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