0672: Regato, Cueva del (Santiago, Cueva de)
Fresnedo top entrance 30T 454378 4801921 (Datum: ETRS89. Accuracy code: M) Altitude 255m
Length 1562m Length 1435m according to Spanish survey
Area position

Updated 13 February 1998; 19th February 1999; 9th November 2003; 1st July 2009; 6th January 2011; 15th September 2013; 21st May 2014; 30th June 2018

See the file for Spanish and English surveys.

The re-exploration of the cave was started at Easter 1994. Most of the cave was re-surveyed during the summer of 1994 with extra work being put in during Whit 95 and the summer of 1997. The description below needs checking and adding to. The original exploration appears to have been quite a thorough job.

The top entrance is just outside the current permit area, the bottom entrance just inside. The hillside follows the dip of the beds as does the cave.

The top entrance rift has an unexplored passage over the top and drops immediately to a scramble down boulders to a tall passage. The first major feature is met after 50m at a decorated junction: the northern passage passes a 9m choked pitch and rises to a draughting, calcite choke after 30m; two small routes to the east soon choke.

The main way on descends to the south and enters a draughting, low calcite slope to a 2m drop. The passage enlarges with routes to a passage below and, after a tight tube on the east side, a bouldery chamber is entered. Turning east at the calcite slope gives a vocal connection with the tight tube, after passing through a rift in shattered rock.

Around the boulder chamber there are climbs up. Beyond the Palacio Bada carbide graffiti there is a passage at floor level which is apparently unexplored by the British but does "go" according to the Spanish survey. The route beyond closes in forcing the explorer into a roof passage 5m above.

To the east, the route rises to a 20m pitch and a choked chamber. There may be a parallel shaft over a mud bank but this requires bolting to get to.

To the west, a traverse reaches a 10m blind pit with a possible climb; below holes lead to the lower level and a junction just inside the bottom entrance. The cave is now described from the bottom entrance, which is a tree filled hole in sloping pasture. A walking slope leads to a greasy slope which is best laddered as a sloping 7m pitch, or can be bypassed to the south by a 3m climb down or to the north by a sloping traverse. (Sixty metres of passage to the north passes a 7m blind pit and eventually chokes close to the surface). The pitch base is the junction described above and the route to the deepest parts of the cave are to the south.

A traverse of some 30m leads into a stal grotto, with a scramble through reaching the top of a greasy slope. This is now also best laddered as a sloping 7m pitch from a stal. Below the ladder a further 5m pitch down a calcite and boulder rimmed hole leads to a false floor and a rift passage. Just where this turns right, a hole in the right hand wall is a 4m pitch into a rift which chokes above a muddy climb after 15m. Walking sized passage continues to a hole in the southern wall marked Sima del Rio and then ascends and closes in with no draught. The 8m pitch meets water is a smallish passage which becomes smaller downstream and continues low and wet.

Above the calcite rimmed pitch, the passage continues eastwards, turns left into a short crawl and enlarges to the head of a 15m pitch. To the right, jammed boulders are crossed to another hole which links with passage below.

At the pitch base, the floor slopes steeply to the north and chokes. To the south the passage ducks under the western wall and continues for 15m through a crawl and emerges in a chamber. Straight ahead the passage changes to a tight 4m climb down which intersects a cross rift which still needs full exploration.

It may be that the cave drains to site 3910, first documented in the summer 2013 but then out of the Matienzo Caves permit area.

The cave was briefly looked at in April 2014 when the visitors "had a look at the entrance series and exited."

References: card; material in file; anon., 1994a (Easter logbook); anon., 1994b (logbook); Corrin J, 1994b (survey); anon., 1995b (Whit logbook); anon., 1997b (logbook); García José León, 1997 (survey); anon., 1999c (logbook); anon., 2009b (Whit logbook); León García José, 2010 (survey); anon., 2014b (Easter logbook)
Entrance picture : bottom and top entrances
Underground picture(s):
Detailed Survey :
1976 (Spanish survey) known cave low res high res
1997 known cave 1:1000

Line Survey :
On area survey :
Survex file :yes (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.)
Passage direction rose diagram: 30/6/2018