Updated  31st October, 17th November 2007; 1st July 2009; 18th January 2011; 11th February 2016; 23rd September 2018; 13th June, 15th November 2022

According to Simonnot G, 2016, the site position is ETRS89 0451628 4793236. The grid reference in León García José, 2010 (Volume 1 and Volume 2) (Cantabria Subterránea. Catálogo Grandes Cavidades) is 30T 0451750 4793450 Alt. 575m (datum possibly ED50?).

The information below has been roughly translated from the French, Spéléo-Club de Dijon reference, Degouve de Nuncques Patrick et Simonnot Guy, 1989 (in Sous le Plancher, no 4, 1989) and Simonnot G, 2016.

   The entrance is about fifty meters above the huts of Tocornal, ten under the small col between Piluca and El Castro. The pit was first shown to the French by a shepherd in August 1987. A first trip in April 1988 to -40 m revealed the presence of a large pitch which was descended in August 88 during a single exploration.
The opening (8m X 2m) lies in a grassy moor, not making the rigging of the first pitch (22m) very easy. The base is the crossroads of three galleries. Two of them (the Northern and Western gallery) are upstream inlets which begin with beautiful meanders (8 X 2) which are not long in narrowing to become impenetrable. The Western gallery may have a continuation at the top of a 3m climb. The third gallery contains an enormous decorated block that slopes down to the upper lip of Odyssée Pitch (p207).
   Thick layers of moonmilk cover the walls and it is very difficult to rig. Fortunately, a few meters before, a hole with a strong draught (translation?) leads to a pitch of 10 m which joins a alcove occupied by a gour draining into the Odyssée pitch. The descent continues in a decorated 4m diameter tube for 20 m (at -55m). The pitch then enters the gigantic abyss. Lighting from a small halogen torch shows the imposing solid masses of stalagmites. The variable consistency of the decorated walls does not make rigging easy and the two spits which held the last section (109m free hanging) "were the occasion of many cold sweats".
The base of the pitch (-240m), is somewhat narrower (30m x15 m) and is occupied by active stalagmites. At the lowest point, a narrow section gives access to a final squeeze where the system closes in at -251m.
   Members of the Asociación Espeleologica Conquense Lobetum, who have the permit for the Cruz Uzano / Ogarrio side, have also explored this site. They have traversed around the top of the big pitch (on large bolts) to a passage that has climbs up and appears to be heading back to the surface. Valero Enrique y Soriano Ángel, 2007 has the depth at 256m and gives a name of Torca del Portillejo.
   The Torca del Portillero occupies a quite remarkable position about the axis of the synclinal structure that crosses the peaks of El Castro. The entrance shaft opens at the base of Linares limestone, then the cavity joins the slim and stunning ground area which marks the syncline. The Tocornal sandstone Tocornal (or Colorado sandstone) is pierced and the Odyssey pitch reaches the level of the Vallina limestone.

Reference: Degouve de Nuncques Patrick et Simonnot Guy, 1989 (survey); anon., 2000e; pers comm (email 10/5/2002); Corrin Juan, 2003b; Valero Enrique y Soriano Ángel, 2007; anon., 2009b (Whit logbook); León García José, 2010 (Volume 1 and Volume 2) (survey); Simonnot G, 2016; Simonnot G, 2018; Simonnot G, 2022
Entrance pictures: yes
Underground picture(s):
Detailed survey: plan  section  (from Degouve de Nuncques Patrick et Simonnot Guy, 1989)
Line survey:
On area survey:
Survex file: reconstructed from plan and elevation (June 2022) : with Cueva Vallina