Tresviso Caves Project

Tresviso Caves Project Gazetter

T87: Mazarrasa

(Cueva de Mazarrasa, Torca de Mazarrasa, Remon)

Area:Mazarrasa Mines
East, North:360912, 4785988 (nearby)
Coordinate Quality:Uncertain
Long, Lat:-4.7123602013693, 43.213837618493 (map)
Elevation (m):1717
Length (m):1720
Depth (m):-318
Active Lead:
Survey Available:


Obvious mine entrance at the side of Caseton de Andara (Caseton de Andara). The entrance is completely collapsed and access is not possible. There are probably other ways into the system, from higher mine entrance, but no connections have been made as of 2017. COLLAPSED - NO ENTRY POSSIBLE


stooping mine entrance, now collapsed (2010) Entrance


This is a really sporting trip with lots of long pitches. A stooping mine entrance (collapsed - 2010) leads to a dam. Continuing on, through knee deep water, a natural shaft is reached. This is the head of a 55m pitch into Mazarrasa.
Past the Mazarrasa shaft, is another shaft on the right, with a plank over the top (shaft is blind).  The passage continues along an old railway line to blind workings. Above the shaft is a mined fault, this can be scaled via two 5m wooden ladders  into further mined passage.  There are another 2 ladders above (not ascended)  Following the mined passage leads leads to a split.  The right passage leads past a rubbish filled hole to natural passage and a 5m climb into a boulder choke.  Left leads to various climbs and mine levels
Mazarrasa 'Proper'
Bolts in the wall give a good free hang all the way to the bottom, where a boulder slope is reached. A 9m pitch follows. From the bottom a loose boulder slope leads to the head of a 15m pitch. Below, another boulder slope, followed by a 3m climb, leads to a 45m pitch, Pendulum Pot. It is possible to pendulum into an obvious side passage 10m from the bottom of the pitch. A 13m pitch, follows shortly and at its bottom a short traverse leads to a large hole in the floor. A 4m pitch, followed by a short climb returns you to the big shaft which is 29m deep. From the Large Chamber the way on is down a 3m climb and along a tight rift.
A crawl leads to a 24m pitch and large boulder chamber. Continue down the boulder slope until the far wall is reached. After a slide and climb down between the wall and boulders the passage continues to a series of short climbs. Next follows a series of sporting pitches in easy going passage. Eventually the rift narrows and the going becomes more difficult. After a small chamber the way on is either at floor level, which is tight and strenuous, or a traverse along in wider passage, followed by a 9m pitch to floor level.  A 6m pitch is reached which drops into a small chamber. The going becomes easy again but only for a short distance, before the rift becomes very tight. It can be followed for another 100m, past a small inlet to a sump.   
No ways on were found  2010 - Entrance has now collapsed - upper entrance?


  • L.U.S.S. (1977)
  • Anon. (1978). “List of Caves”. En “LUSS. Expeditions to Tresvisoand the Picos de Europa in northern Spain 1974-1977”. Pp. 34-66.
  • L.U.S.S. (1980), Tresviso 1980.
  • Anon. (1981). “Mines and pots re-explored”. En “Tresviso 80. An expedition to the Picos de Europa, Northern Spain, 1980”. L.U.S.S. Pp. 4-9.
  • Sefton, M. (1984). “Cave explorations around Tresviso, Picos de Europa, Northern Spain”. Cave Science vol. 11-4:199-237.
  • S.E.I.I. (1982). “Expediciones a Tresviso”. Cuadernos de Espeleología -9/10-183-214.
  • Chapman, P. (1983). “Cave invertebrates from the Picos de Europa, N. Spain”. Cave Science vol. 10, nº 1:30-34
  • T.C.P. (2017)
  • Notes

  • Entrance now collapsed (2010) Alternative co-ords:
  • 0360933 4785987
  • 0360938 4786015
  • 0360970 4786200
  • 0360970 4786200 1730 m (Cant Sub 2010)
  • 0360912 4785988 (2
  • Images