025 Sima-Cueva del Risco
El Sedo VN53309604 Alt. 196m Length 9859m

Updated 19th February 1999; 28th July 2000; 26th October 2001; 2nd March, 6th October 2002; 6th November 2003; 8th October 2005

The usual entrance, Torca del Sedo is situated behind a group of houses at Sedo. A short clamber down leads to the 8m pitch head. The descent can be damp and the base is strewn with rubbish. Two ways are possible at the bottom: downstream leads into the Cueva de Tiva (026) while a 2m climb in the opposite direction leads into the entrance series of Risco.

After 100m of large passage the stream is met and wading in 1m deep pools is needed. To the left are two high level passages both of which choke after about 100m. Straight ahead the streamway continues high and wide to a junction with a passage on the right. This leads to several dismal chambers and no way on is possible. The main streamway continues through deep pools and mud banks until the Tonto Series is met on the right. This uninviting, low passage splits after 200m and then chokes.

The 50-100m long Dambuster Series is reached by climbing across the top of 30m avens on the south side of the passage just before reaching the Tonto Series. Five metre diameter, well decorated, parallel passages with deep holes end at a sandstone breakdown.

The main passage runs for another 100m before reaching the most important junction in the cave. At this point the right hand, narrow and very wet passage can be followed up to the superb Pinto Gallery. This vadose passage contains a large stream and can be followed for almost 2km until it splits into the various feeder inlets which have their origins in the Jivero/Tali/Anderal complex of caves. Although there is much evidence of surface debris, no surface connection has been made. Archaeological finds made in this area are described below.

Back at the main junction it is possible to climb up straight ahead into a large boulder chamber where 2 routes are possible. The fine Arco Gallery goes off at high level and is typically 3 - 5m wide and 15m high. This runs for 400m, around two holes, until it breaks out into the roof of the Risco River Gallery and progress is halted. (In 1992, on the way back, two passages on the left were looked at. Chambers at the end were reached by smashing through stal). In fact the Arco Gallery is the old, abandoned route and the present stream has cut down to a lower level. This can be joined from the boulder slope at the start of the Arco Gallery and is easy going except for the occasional climb over boulder piles.

The Risco River Gallery continues for approximately 1km until it emerges into the impressive Sala Carballo which is a large boulder filled chamber. The main inlet tumbles down from high up on one wall - this is the 19m pitch in from Cueva Oñite (site 027). This was bypassed with a route through from Oñite discovered in 2005.

On the opposite side of the Sala Carballo a large dry passage (Gran Risco) heads off above the main river and probably originally connected with the Arco Gallery. After 300m it becomes choked with calcite deposits.

In 1994, the deep hole down to the river at the end of the Arco Gallery was traversed over. A bolt route leads up to the left after a 4m climb over boulders. This reaches a dangerous climb up through boulders and a slot up into a big chamber. Most routes are well decorated with calcite. The upper gallery goes back across the chamber. A side passage up a 15m climb leads to Disney World with amazing formations including a triangular mono crystal stalagmite about 1m high. (A photocopy of a section from Cave Minerals of the World is in the Risco file). The route continues as the high level Arco 2. Solid roof is seen with no indication of any inlets from Muela / Mullir. Some 300m along it is possible to abseil down into the main Arco Gallery and this is the safest way up to the extensions. Arco 2 ends at a traverse with no ledges where bolting is required.

Archaeological remains have been discovered. The S.E.S.S. found remains of a large deer, possibly Cervus megaceros, while in 1975, in the same area (the end of the Pinto Gallery), L. Mills discovered a palaeolithic bone spearhead also described as a mono-bevelled bone assegai, 8.5cm in length and with a circular cross-section, possibly Magdalenian.  More recently, the possibility of more remains and small engravings has been published but not fully investigated. Photographs of engravings on the walls can be seen here. (See also Ruiz Cobo Jesús and Smith Peter et al, 2001)

Ortiz in Algunos crustaceous y miriapodas cavernicolas de la Region de Matienzo, Santander (Ortiz E, 1968) describes 18 individuals of Gammarus berilloni Catta.

A dye test in 1964 showed water from Sima-Cueva del Risco resurging after five hours from La Lisa below Cueva de Gonzales (014), Cueva de Transformador (032) and in Cueva de Tiva (026).

References: Fernández Gutiérrez Juan Carlos, 1965; Fernández Gutiérrez et al, 1966 (survey and photo); anon., 1974b (logbook); anon., 1974a (survey); Cox G, 1973; Fernández Gutiérrez J C, 1975; anon., 1975b (logbook); Kendal Caving Club and Manchester University Speleological Society, 1975 (survey and photo); anon., 1977b (logbook); anon., 1978 (logbook); Manchester University Speleological Society, 1982 (survey and photo); Mills L D J, 1981; Mills L D J and Waltham A C, 1981 (survey); Mills L D J and Waltham A C, 1981 (survey and photo); Smith P, 1981a; Corrin J S and Smith P, 1981; anon., 1981 (logbook); anon., 1982 (logbook); Corrin J, 1983c (photo); anon., 1986 (logbook); material in file; Ortiz E, 1968; anon., 1992b (logbook); Cawthorne B, 1992; Corrin J, 1992b (survey); anon., 1993b (logbook); Muñoz E and Bermejo A, 1987; anon., 1994b (logbook); Corrin J, 1994b (survey); Fernández Ortega F, Valls Uriol and Maria del Carmen, 1998; García José León, 1997 (survey and photo); Corrin Juan, 1997c; anon., 1999c (logbook); Corrin Juan, 2001a; Ruiz Cobo Jesús and Smith Peter et al, 2001 (includes drawing); anon., 2002b (summer logbook); Corrin Juan, 2003b; Ruiz Cobo Jesús and Smith Peter, 2003; anon., 2005b (Easter & summer logbook) 
Entrance picture : yes
Underground picture(s): near the end of the Pinto Gallery
Scanned slides from 1977, 1978 by Frank Addis

water- fall

tusk

Detailed Survey : from 1965: low res  high res  Oñite survey updated 2005
Line Survey :
On area survey : 1975 Ozana area map. Not a lot of detail. low res  high res
Survex file :