0102: Castañas, Cueva de la
Riaño 30T 452401 4799804 (Datum: ETRS89. Accuracy code: A) Altitude 198m
Length 382m Depth 44m (Length calculated as 258m surveyed in 2017 + passages from old survey)
Area position

Updated 15th April, 12th November 2002; 4th May 2009; 18th February 2012; 9th September 2017

   A depression with chestnut trees contains a number of entrances all of which unite at a 9m pitch. At the base, 30m of walking leads to a climb of 7m and then varied going to a large chamber. An inlet can be followed for 60m to its end at two large avens.

   Downstream, the passage heads back towards the entrance but becomes smaller as a hands and knees crawl then ends at a strongly draughting, tight, muddy crawl. This was excavated in July 2017 but was found to continue very low and awkward over rocks and mud. A dye test has shown a connection to the last inlet on the left in the Gorilla Walk. The cave appears on the Cueva Hoyuca and the Four Valleys System Hydrology diagram.

   The cave was surveyed in July 2017 to provide a centre line and z data. As the terminal crawl ends about 200m from the Gorilla Walk in Cueva de la Hoyuca (107) and is at the same altitude, the cave is most unlikely to provide an alternative entrance into Hoyuca in the near future.

References: Kendal Caving Club and Manchester University Speleological Society, 1975 (survey); Mills L D J and Waltham A C, 1981 (survey); Corrin J S and Smith P, 1981; Manchester University Speleological Society, 1982; anon., 1988 (logbook); anon., 2002a (Easter logbook); anon., 2009a (Easter logbook); anon., 2017s (summer logbook)
Entrance pictures : yes

Underground pictures: July 2017
Detailed Survey : jpg from 1975 journal : pdf, July 2017
Line Survey :
On area survey :
Survex file : from July 2017 survey
Hydrology : (Terry Whitaker): Hoyuca and the 4 Valleys System