Updated 12th February, 8th May, 28th October, 11th November 2016; 24th September 2018; 3rd March 2020; 22nd September, 17th November 2022

  [Estimated length]
   A couple of holes on the east side of the Torca del Hoyón depression. They lie each side of a fence in the wood and a stream can be heard inside. Some work was required at the top of the shaft before it was explored.
   This was part explored at Easter 2016 down a p6 then a 2m climb where 2 streams meet. At the end of August rocks were cleared from an going rift passage. (The stream, which was a small trickle, vanished to the west side into the floor.) After about 8m it became a little low and the passage dropped through a squeeze into the continuation of the streamway. Crawling in pools for about 8m in a rectangular passage 0.5 x 1.2m led to a calcited mud and gravel bank. This has been excavated to allow continued crawling to a small pitch. There is a steady inward draught. [Passage description (now out-of-date): Terry Whitaker]

Simonnot G, 2018 has an account of the August 2016 dig.

   On April 7th, 2016, at about 1430, 5 litres of optical brightener were injected and a strong positive was detected at Comellantes on 10th April and found to be still positive on April 13th. Detectors were placed in a number of other resurgences as described in the Easter 2016 summary:
1: the stream below Cueva del Arenal (0035) where it joins the stream in the valley running down on the south side,
2: Cueva del Molino resurgence (0791),
3: the Bustablado river just upstream of site 791,
4: Fuente Aguanaz (0713), and
5: Fuente Molino (2364) near La Cavada.
    This test confirms one made many years ago, which was suspect due to possible contamination, and shows that the South Vega System must extend at least to the Alisas road area, confirming it should extend into the large blank area to the west of the present system. Together with last year’s test from Cueva Vallina (0733) this more than suggests that there is potential for a 100km plus system.

   A Tejuelo group has been in the cave some time in the winter 2019 / 2020 but no more details are known. Further work is known about, but is not yet for publication. (See JSC, card index)

Reference: anon., 2015d (autumn logbook); anon., 2016a (January, February logbook); anon., 2016b (Easter logbook); anon., 2016c (summer logbook); Simonnot G, 2018; anon., 2020a (January, February logbook); anon., 2022c (summer logbook) - paper; Simonnot G, 2022
Entrance pictures : January 2016 : Easter 2016 : summer 2016
Underground pictures : August 2016 - 1 : August 2016 -2
Video : First pitch exploration (YouTube) : underground dig (YouTube)
Detailed survey :
Line Survey :
On area survey :
Survex file : On Torca del Hoyón doline surface survey (out-of-date)