Updated 8th June 1998; 17th September 2000; April 29th, 7th October 2001; 27th October 2007; 4th May, 24th October 2009; 6th January 2011; 17th September 2014; 13th January, 27th September 2015; 25th February 2016; 20th May, 6th July, 17th September 2017; 30th June 2018; 24th September 2024

NOTE (summer 2024): The rope in the first chamber going up to the higher level crawl is in a bad state and is knotted. It should be replaced.

The entrance, in a small depression on a hillside, may be filled in with a couple of boulders but they can easily be removed.

The small, often strongly draughting entrance leads to a clamber down to the head of a 3m vertical climb to a short ladder pitch into a passage, 3m wide by 4m high, which ends after 20m in a chamber. The floor is a large boulder choke. A 4m pitch on the left enters a tight passage, while a small passage on the left near the entrance leads to an aven.

The draughting way on is a hands and knees crawl at roof level on the right. Entry to this is gained by climbing off a large block over a drop near the right hand wall. This climb can be awkward on the descent and should be laddered and lined.

In the roof, two holes are bypassed by squeezing up to the left and a third by clipping into a lined traverse. A short crawl leads to a slip down behind a column into a 15m wide, 10m high and 30m long fault chamber.

At the far end of the chamber several inter-connected, small phreatic chambers and tubes lead off. On the right, after walking up a slope, a short drop through boulders leads to the passage splitting. To the left lies 70m of small passage with occasional small chambers first entered in 1993.

Straight ahead and to the right, after 20m, is a tight rift on the left and on the right a flatout crawl at floor level. This emerges into the third, large and final chamber.

To the right is an area of fallen blocks and pits. One hole is a sloping climb down over calcite into a solid-walled chamber. To the left is a 6m passage which closes down while to the right is a rift passage ending in a calcite choke, probably still under the main chamber. At Easter 1998, a 12m pitch was descended.

On the left of the final chamber a 5m climb up leads to an extensive area of inter-connected chambers. Keeping left in these leads back over the top of the flatout crawl to a 10m pitch down into the second chamber. This was detackled in 1994 but has a wire attached.

Opposite where the crawl emerges into the second chamber, a 7m diameter tube with a trench in the floor, rises slowly until after 25m a large inlet is seen on the right. This ends disappointingly at a boulder choke after 20m. Hidden behind a block at floor level, on the left, a small gently draughting tube rises to the head of two 30m pitches. No way on has been found at the bottom.

The main passage continues straight ahead where boulder falls force the explorer to roof level. The passage ends in a confusion of fallen blocks. Just before the end a small tube on the right leads to a blind rift down and an aven above on the right. Three metres up the left hand wall a draught can be detected emerging from between boulders. On the left, near the end (station 50), a route through can be followed to a partly explored series of pitches. These drops were originally explored on ladders to a depth of about 50m with apparently another 30m to go. An account of the whereabouts of the pitches can be seen in anon., 2000c (Summer log) dated 12th August and reference is made to 9th August 1987. The draught at the entrance cannot be accounted for by the two known draughts. At Easter 2001, these pitches were finally explored over 2 days to -69m (see survey links below). The last 15m is a free climb. (Note: Are the pitches mentioned in the previous paragraph the same ones? The pitches survey was connected at station 45, not at station 50. Is this correct?).

The cave is on the same level as the middle, Golden Void Series in Torca del Mostajo (071), about 235 - 245m altitude.

At Easter 2009, most of the cave was re-explored, some re-surveying was carried out and a definitive survey might be drawn up. In the summer, a 28m extension was made in Helictite Passage but the way on is choked with more formations.

A small amount of resurveying was carried out in the entrance in the summer 2014. A resurvey of the system was started in the summer 2015 and continued with batch 2015-7, when a possibly undescended pitch was encountered. Work continued in 2016 and 2017 to complete the underground measurements. A new survey and more complete description will appear in due course. The revised length is 1137m (from 1029m). A trip was made into the cave in August 2024 to check question marks on the gestating survey.

References: anon., 1981a (logbook); anon., 1982 (logbook); Corrin J, 1983c; anon., 1984 (logbook) (survey); anon., 1985b (logbook); Corrin J, 1986 (survey); anon., 1986 (logbook); material in file; anon., 1987 (logbook); Corrin J and Knights S, 1988; anon., 1989 (logbook); anon., 1990b (logbook); anon., 1993c (Easter logbook); anon., 1993b (logbook); Neill Alasdair and Jackson Keith, 1993; Corrin J, 1994a (survey); Corrin Juan, 1995b (survey); anon., 1994b (logbook); anon., 1997c (Christmas logbook); anon., 1998a (Easter logbook); anon., 1999c (logbook); anon., 2000c (Summer logbook); anon., 2001a (Easter logbook); anon., 2001c (Summer logbook); Corrin Juan, 2003a; Corrin Juan and Smith Peter, 2007; anon., 2009a (Easter logbook); anon., 2009c (summer logbook); Corrin Juan, 2010 (photos); León García José, 2010 (Volume 1 and Volume 2) (line survey and photos); anon., 2014c (summer logbook); anon., 2014e (Christmas logbook); anon., 2015c (summer logbook); anon., 2016a (January, February logbook); anon., 2017b (Easter logbook); anon., 2017c (summer logbook); anon., 2024d (summer logbook)
Entrance picture : yes  close up  from a distance
Underground picture(s): helictites 1  2  3  4  5  surveying  crawl into chamber 2  line over pit
42 photographs taken at Easter 2009 : 24 photos in Helictite Passage taken summer 2009
photos taken August 2017 during survey trip
Video : Cueva 415 (Espeleo50 - 23/1/2017 - YouTube)
Detailed Survey : line survey plan 1:1000  line survey elevation 1:1000  sketch of end pitches
Line Survey : interesting position cf North Vega System
On area survey :
Survex file : summer 2017 (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.)  
with N Vega System (After summer 2017) (Amended magnetic declination December 2013 to align with Eur79 grid.)
Passage direction rose diagram: 30/6/2018