Updated 11th May 2002; 2nd November 2004; 9th February 2016; 21st September 2018; 14th November 2022

The entrance lies about 350m northwest of the El Castro summit. A 7.5m entrance pitch, rigged from the lip on the south side, drops into a large, descending, 100m x 30m chamber with formations. The Spéléo-Club de Dijon have also explored the site (August 1988) and named it Cueva Bornea (SCD2004); the local name is Muesa.
The cave is apparently developed along the fault seen in site 1745, Torca de Portillero de Tocornal. The smaller passage marked on the French survey may be worth digging. The cave may have been extended in 2004 through a decorated crawl for 10m just to the east of that passage.
The 36m depth is from the top of the depression, according to the French survey, although the British one shows a depth of 45m.

References: Corrin J S and Smith P, 1981; material in file; Degouve de Nuncques Patrick et Simonnot Guy, 1989 (survey); Corrin Juan, 2006; Simonnot G, 2016; Simonnot G, 2018; Simonnot G, 2022
Entrance pictures : yes
Underground picture(s):
Video: descent of entrance pitch   main chamber   decorated crawl   ascending entrance pitch
Detailed Survey : 1:1000 (British: this is 180deg out and requires altering)  plan and section (French)
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.)