1350: Hoyos, Sumidero de los (2312 (French: SCD))
Arredondo 30T 450183 4792590 (Datum: ETRS89. Accuracy code: G) Altitude 452m
Length 85m Depth 6m
Area position

Updated April 20th 1999; 13th October 2004; 11th February 2016; 23rd September 2018; 28th January 2019

Site explored and surveyed by the Catalans in October 1998.
The site lies at the base of a closed depression in woods. There are three entrances - two low in the base of the cliff and one a pitch entrance a few metres up. Marked VT with a square and diagonal line.

The following is a (Google) translation of a description by Guy Simonnot (Simonnot G, 2019):
The entrance porch (4 x 1 m) overlooks a low gallery with holes left at first on the left by a collapse (2 m) going up in the open air then by a chimney of 5 m also joining the surface. Ten meters further the conduit separates into two.
On the right the route goes into a modest gallery, embellished with some concretions, then the dimensions increase. The creek dug its bed right on the concave shore in marly layers while on the left it spread beautiful layers of clay.
On the left of the diffluence the gallery crosses a small scree room then stumbles on a concrete wall that one must climb. An enlarged passage leads to a toboggan covered with stalagmites. At the foot we reach the confluence with the active gallery and the most spacious part of the cavity.
The width is around 10 m and 5 m in height, a meander vault unfortunately ends on a stalagmitic flow. Downstream of more and more thick clayey deposits have been recreated by the creek. Funnels without follow-up mark the places of disappearance.
Geological level:
It is on a fracture (N80°) putting in contact the sandstones of Colorao (= sandstone of Tocornal) with the limestones of Vallina. The dip of the strata is about 10° to the north. The water joins the network of the Vallina and the drainage towards the source of Comediante (Matienzo)

[A copy of the .tro file (for Visual Topo?) is found in the 1350 surveys folder.]

Reference: material in file; anon., 1999a (Easter logbook); anon., 2004d (summer logbook); Simonnot G, 2016; Simonnot G, 2018; Simonnot G, 2019
Entrance picture: distant   close up
Underground picture(s):
Detailed survey: plan : section
Line survey:
On area survey:
Survex file: yes (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.)