Tresviso Caves Project

Tresviso Caves Project Gazetter

T91A: Torca Boulderosa

(Torca del Ramazosa, Sistema Boulderosa-Italianos, Sima Bulderosa, Sima Boulderosa)

Area:Mazarrasa Mines
East, North:0, 0
Coordinate Quality:No location
Long, Lat:-7.4887438971664, 0
Elevation (m):0
Length (m):587
Depth (m):-313
System:Sistema Ramazosa
Active Lead:
Survey Available:


Obvious hole in side of mined passage between last pitch in T105 Italianos and the mine level between T91A Lower Caseton de Andara Mine and RCA6. T105 Italianos is the only currently known accessible and safe entrance into the system


Opens through a small hole, at side of the mine passage in Lower Caseton de Andara mine / RCA6


The 30m first pitch is free hanging for 18m to a 2m wide ledge from which a Y-hang gives another 12m free hang to the bottom of the pitch. The chamber is about 3m wide with two narrow rifts in opposite corners, and is littered with rubble. The southern-most exit was not descended as the 1970's reports claimed it was choked, however in 2015 dropped rocks fell for at least 2 seconds suggesting it was not!

2015 extensions

The passage from the other side of the chamber drops down a 5m very loose ramp to the top of the 1970's 58m pitch. With a tight take off this pitch is split by four bolts to give abrasion free hangs past numerous ledges and boulders in the rift.In 2015, a 50m traverse (Gung Ho!) was made above the 1970's pitch, the Pele Rocco Pitch's begin where the passage widens this is a series of 10-20m pitch's landing in an active inlet.Part way down The Pele Rocco Pitch's a large, blind shaft reached via a traverse and marks the northern limit of the rift and is the source of the below inlet. Following the inlet downstream leads to a 5m upwards ramp leaving the water below.

A short 8m pitch leads to a tight take off and an 18m pitch in the rift, gradually increasing in size to land in a sizable chamber with a very loose, sloping floor. Two short pitch's on equally loose footing lead to a grand 30m+ free hang, re-joining the 1970's route in a large 10x20m chamber.An active inlet enters to the North and the obvious rift continues south

Original route re-joined

Traversing along the rift over the boulder leads to a 5m climb down into a small chamber where the first meander is reached. This is best tackled by leaving the chamber at the same level it was entered. The route is pitch marked with unfathomable carbide symbols. A small pitch is traversed over (the original report states this is 20m and blind, unconfirmed in 2015, although a spit was seen) however, if high in the meander this may pass un-noticed. 10m after the blind pit the rift opens out, the 1970's route drops immediately into a 15m and 35m pitch. The 2015 route traversed until the rift could be seen to end. Here the grand 50m pitch is split by a Y hang after 8m into a second large boulder chamber. Directly below the ropes a steeply descending chute quickly becomes too narrow. As before the main rift continues from the southern end of the chamber. A large window above the rift enters an aven of similar dimensions to the previous pitch.

Like the previous chamber, the meander quickly narrows to a winding awkward passage and is best traversed at a 'mid-level' for 50m to a small chamber, following more unfathomable carbide symbols. The chamber has an active inlet and the water continues along the rift floor. Climbing out of the chamber leads to more of the same (35m) until a 2nd small chamber is reached. A final 15m of meander ends in an awkward take off for a 10m pitch to a large ledge.

At this level the main rift continues over an inlet and can be reached by a traverse - this showed no sign of previous passage and was not entered in 2015 due to a lack of bolts, but is assumed to re-join the 1970's route below Donald Duck. The 1970's route is followed down a descending 10m ramp to a large aven with an active inlet flowing into a constricted meander. Following the water over Donald Duck leads to a tight wet take off into immediately larger surroundings.

There is a potential passage accessed by climbing over the Donald Duck approach crawl while still on the ledge at the bottom of the pitch before entering the crawl itself. On the far side of the duck, there is appears to be a large passage opening heading back to the other side and a vocal connection was established on the 2015 de-rigging trip. A damp 65m pitch is broken by a large ledge after 10m followed by a huge 55m free hang. This was broken 15m off the floor by a ledge on the right hand wall to escape the waterfall (if re-rigging it would be better to traverse out left higher up to escape water). The next chamber is very drafty and boulder strewn, it contains an impressive calcite collapse and a further stream inlet and downstream meander.

Heading upstream, the wide meander of this inlet is followed for an estimated 75m which then breaks out to a larger chamber with a 15m waterfall, where the stream way can be seen to continue (unclimbed - require aid). Downstream, the draft is followed into a cherty, meandering rift (for about 75m) to the head of the next 50m pitch. (There are a series of side chambers off the stream way before the 50m pitch but these do not appear to lead anywhere). The pitch is broken by two rebelays and lands in the Terminal Chamber.

There is also a third unexplored potential way from the drafty chamber, marked on the survey near the centre of the chamber.

Terminal Chamber is a large boulder strewn hall, the floor is a mix of large boulders and smaller cobblestone rocks. There are two large dry and one wet aven (unclimbed). Also what looks to be a higher level chamber, via a short aided climb towards the top of the obvious scree slope (unclimbed).

There was no obvious route to be found through the boulders. The water entering the chamber disperses through the cobbled floor


Anon.. (1980). "Tresviso 1979". Jumar-4:20-30.
S.E.I.I. (1982). "Expediciones a Tresviso". Cuadernos de Espeleologia -9/10-183-214.
Anonimo. (1978). "List of Caves". En "LUSS. Expeditions to Tresviso and the Picos de Europa in northern Spain 1974-1977". Pp.34-66.
SEII. (1978). "Tresviso 78". SEII. Informe inedito.
Anonimo. (1978). "Tresviso 78. An expedition to the Picos de Europa, northern Spain- LUSS 1978". LUSS.
Sefton, M. (1980). "Tresviso '79. An expedition to the Picos de Europa". Caves & Caving-9:12-15.
Anonimo. (1980). "Tresviso 79". LUSS.
Sefton, M. (1984). "Cave explorations around Tresviso, Picos de Europa, Northern Spain". Cave Science vol. 11-4:199-237. Caves & Caving No9
Tresviso Caves Project 2015


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