2638 shaft
Riaño 30T 0452147 4800844 Altitude 230m Length 205m + grade 1 extensions  Depth 15m

Updated 10th October 2007; 16th January 2010

Known as the "The Boghole". A small, slab-covered shaft drops 7.5m to a steep, slippery slope into a chamber with a number of passages radiating. The first two on the left quickly join in a lowering crawl to a dig, while the next one up a short slope is a narrow rift to a choke. The final passage is reached via a 1.5m climb up to a tall rift which leads quickly to a choice of routes. The top level - Up Above Passage - can be followed for 60m of walking and stooping to a final short crawl at roof level to a choke on shattered joints.
The lower level - Down Below Passage - starts as a hands-and-knees crawl but quickly slopes down to a larger section just beyond a short, tight inlet on the right. Walking, traversing and scrambling over collapsed boulders leads to final traverse over holes in the floor beside a calcite run down the left wall to end at a small "chamber" formed by breakdown after about 100m. An upper route ends at a dig in boulders after 4m, whilst a floor level route goes a similar distance to a choke of sand and shingle.
Both passages follow exactly the same joint determined route, with several overtight holes linking then through the floor / roof, which for much of the length is unbroken.
Both upper and lower levels end at the choke on shattered joints.

Reference: anon., 2007b (Easter logbook); anon., 2007d (summer logbook); Corrin Juan, 2007a (survey)
Entrance pictures : yes
Underground pictures : yes
Video :
Detailed Survey : Easter 2007: 1:500 pdf    Summer 2007: 1:500 pdf
On Paul Fretwell's latest version of the Fours Valleys survey
Line Survey :
On area survey :
Survex file : yes