0767: Wild Mare, Cave of the
Hornedo 30T 447971 4801318 (Datum: ETRS89. Accuracy code: A) Altitude 70m
ETRS89: 30T 447962 4801332 is a GPS'ed point in the stream bed to the N of the entrance, part of a surface survey to the river
Length 594m now included in the length of Torca la Vaca Height 14m
Area position : A Google search for this site (Wild Mare, Cave of the+Hornedo)

Updated 12th November 2002; 16th April , 25th July, 3rd October , 8th November 2008; 24th February, 5th May, 2nd November 2009; 6th January, 19th, 27th May 2011; 5th May, 25th, 26th September 2012; 16th September 2013; 28th September 2015; 19th February, 28th April 2016; 21st May 2017; 6th May, 30th June 2018

Torca la Vaca (site 2889) was linked through to Cave of the Wild Mare after a series of dives in both caves by Jim Lister and Colin Hayward in April 2012 taking the Torca la Vaca System length to 15222m. The logistics for a two-man diving team exploring up the stream course in Torca la Vaca are easier when the Wild Mare entrance is used rather than taking bottles in through Torca la Vaca.

The opening to Cave of the Wild Mare lies a few metres above the main river at the head of a normally dry river bed. The entrance is 3m high and 6m wide with a strong draught emerging from it. On one visit at Easter 2008, it was reported that huge amounts of water were emerging after one days continuous rain - probably equal to the river at Matienzo in moderate flood. This raises the possibility that this site is acting as a flood overflow for Fuente Aguanaz, 1.5km to the west. It is assumed that the cave acts as the resurgence for all the water in Torca la Vaca, site 2889 and collects water from Torca de Peña Encaramada. Despite complete re-exploration, extensions, pushing and resurveying over four days in the summer of 2008, no link was found with the upstream cave, although water in Wild Mare was muddy - due presumably to the explorations in the watery sections of Torca la Vaca. (Some suggestions about the source of the water are shown here.)
   In April 2012, after moderate rain, the inlet on the true left of the passage after the bouldery area and before the final canal was issuing at least half of the water resurging at the entrance. This is likely to be water from Torca de la Peña Encaramada (site 3380).
   With "lots of water" in the cave, the inlet with the "draughting choked rift" was reached at Easter 2018. There was a large volume of water coming out and a strong smell of rotting matter when the silt was disturbed.

The passage swings right to hands and knees crawling on sharply eroded rock with rippled sand. After 40m it is possible to walk and after 60m pools are met on the left. A branch on the right soon degenerates into an almost flatout crawl over eroded gour pools. This passage draughts strongly and has been pushed to where it splits and becomes too small. Part way along is a low sandy bedding which has been dug to a cross rift 15m high and 20m long which draughts slightly. This was climbed in 2008 to a strongly draughting passage which choked.

The eastern passage has deep water and passes through areas of breakdown with avens. The route ends at deep water in a cross rift. The water emerges from beneath the southern wall of the rift. This was dived in 1995, through the 50m long Sump of the Wild Eels to 50m of passage and further cross rifts with draughts but no apparent way on. Small sumps in the floor appeared to offer little hope for extension.
At Easter 2011, Jim Lister and Colin Hayward in Torca la Vaca passed downstream through a 25m long sump to emerge in a chamber with a another sump. This was later named Eely Mud Eye Chamber. Diving in April 2012, they dived the sump at the northern end of Eely Mud Eye Chamber into AGM Bypass, a rifty, bouldery chamber with a number of routes. One of these, the first Vaca - Wild Mare connection, dropped the divers into the furthest rift west in Terminal Chamber. Further exploration saw the divers passing downstream through the northern "small sump in the floor" into Terminal Chamber. Another sump in Terminal Chamber was pushed (with 27m of line) into an enlarged bedding and rift where it was just possible to turn around in the blind end. A video of the dives on YouTube can be seen here. A diving blog has also been put online the text of which can be seen here.

Dives further upstream in Torca la Vaca were carried out at Easter and summer 2013. They are documented in the Vaca description.

Climbs in the rifts before the Sump of the Wild Eels have been attempted but protection and/or a maypole on the rotten rock may be advisable. The main draught appears to come from a high cross rift just before the sump and, next to the sump, a hammered-out, narrow rift has been pushed to a choke with a possible passage about 5 to 10m above. In summer 2009, the last rift at the sump was climbed, but there was no draught and no way on.

   A diagram of the hydrology of the San Antonio - Hornedo - Cobadal area drawn after Easter 2011 can be found here. Detectors were placed downstream of the resurgence for a water trace from Duck Pond Sink (site 1976) at Easter 2016. The optical brightener came through at Fuente Aguanaz. The detectors here gave a negative reaction.
At Easter 2017, fluorocapteurs were also negative for an OBA trace from El Cubillón (2538) which came through to Fuente Aguanaz in 6 - 8 days. More details are shown here.
   Over Easter 2018, optical brightener was injected into site 1969 near Alisas and detected between 2 and 3 days later at Fuente Aguanaz (in flood conditions). This cave was also checked and proved negative. (Details of the water trace can be found here.)

Link to entry in the Cave Diving Sump Index.

Reference: anon., 1989 (logbook); material in file; anon., 1994a (Easter logbook); Corrin J, 1994b (survey); anon., 1995c (logbook); Corrin Juan, 1995a; Corrin Juan, 1996 (survey); anon., 2008c (Easter logbook); anon., 2008e (summer logbook); Corrin Juan, 2009; anon., 2009c (summer logbook); Corrin Juan, 2011; anon., 2011b (Easter logbook); anon., 2012b (Easter logbook); Ruiz Cobo J and Muñoz Fernández E, 2013; Corrin Juan, 2013a; anon., 2013d (summer logbook); ; anon., 2015c (summer logbook); anon., 2016b (Easter logbook); anon., 2017b (Easter logbook); anon., 2018b (Easter logbook)
Entrance pictures : yes : Easter 2012 : summer 2013
Underground picture(s): summer 2008 : Easter 2012 : summer 2012 (including dive material in Torca la Vaca) : summer 2013
Detailed Survey : 1:1000 from 1989 / 1995  10Mb pdf file: 2008 resurvey and extensions : Easter 2012, updated after link to Torca la Vaca
Video : Divers link Torca la Vaca to Cave of the Wild Mare, April 2012 (YouTube) : 2012 summer (YouTube) : 2013 photo trip (YouTube)
Line Survey :
On area survey :
Survex file : stand alone (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.) 
with Torca La Vaca and others (summer 2013) (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