Tresviso Caves Project

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T87: Mazarrasa

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

Approach
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 entrances, but no connections have been made as of 2024. COLLAPSED - NO ENTRY POSSIBLE

Entrance
stooping mine entrance, now collapsed (2010) Entrance

Description
Note: There may be major error in original LUSS survey, related to scale. 70's schematics suggest natural cave encountered around 100m in to adit, not >200m as per LUSS survey. This would change where to look for alternative ways in!

This is a really sporting trip with lots of long pitches. A stooping mine entrance (collapsed - impassable) leads to a dam. Continuing, through knee deep water, a natural shaft is reached. This is the head of a 55m pitch into Mazarrasa ‘proper’

Past the P55 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). The mined passage leads to a junction. 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 (not fully explored)

Mazarrasa 'proper'

The main natural cave starts at the P55. Bolts in the wall give a good free hang all the way to the bottom, where a boulder slope is reached. A P9 follows and from the bottom of this pitch a loose boulder slope leads to the head of a P15.

Below, another boulder slope, followed by a 3m climb, leads to a P45, Pendulum Pot. It is possible to pendulum into an obvious side passage 10-15m from the bottom of the pitch. A P13 follows shortly and at its bottom a short traverse leads to a large hole in the floor.

A P4 followed by a short climb leads to a P29 (possible continuation of the previous P45 and another parallel shaft above) which lands in a chamber. The way on is down a 3m climb into a tight rift.

A crawl leads to a P24 and the large Boulder Chamber (there is a high level aven / shaft entering above the chamber). Down the boulder slope and at the far wall is a slot and climb down between the wall and boulders. The passage continues to a series of short climbs and sporting pitches (c3, P8, c3, P8, P4, P7)

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 P9 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

Reference
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 Espeleologia -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)

Images
Entrance