Oxford University Cave Club

"Ario 2000" Expedition Final Report

Picos de Europa, Spain

3rd July - 22nd August 2000

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Pippa Crosby

Since 1961, Oxford University Cave Club has been exploring the limestone karst of the Western Massif of the Picos de Europa. Several huge cave systems have been found, explored and meticulously surveyed, and over the years we have pieced together an ever-expanding picture of the underground complex hidden in these mountains. Exploration in recent years has focused on "Pozu Jultayu", also known as "Pozu del Ojo de la Bruja" or "2/7". The entrance of this cave system was discovered by the 1981 expedition and by 1999 the cave stood at 822m depth, with nearly ten kilometres of passage surveyed. The cave quickly drops from its mountaintop entrance down a series of vertical shafts to a streamway at -700m; the streamway then extends horizontally both upstream and downstream.

The understanding of the local geology we had gained over the years suggested that exploring the current known limits of 2/7 could reveal not only substantial amounts of further passage but several possible connections between 2/7 and other cave systems in the area. Our main aim was to go upstream. In 1999, exploration had been stopped by a section of deep water.

We planned to return with a Goon suit, allowing someone to walk through the water without getting wet and rig a tension traverse over the streamway. Our surveys showed an inviting 2.5km horizontal distance to the neighbouring Sil de Oliseda and a connection would create a combined system of 20km in length and nearly 1km in depth. A second possible connection was to Systema Verdelluenga, an 8km long complex with a downstream sump tantalizingly close to last year's limit. The worry was that our section of deep water would become the other end of the sump just around the corner... We also hoped to continue digging at Choke Egbert, the downstream limit of exploration. A positive dye trace links the water in the 2/7 streamway to the resurgence at Culiembro, some 2km distant from and 600m below the choke. If we managed to reach the resurgence-level streamway, 2/7 would be among the deepest known caves in the world. However, three previous expeditions had already focused attention on this obstacle and made little progress into the boulder choke.

Alongside the major underground projects, both of which required camping down the cave for 3 or more nights at a time, we had several smaller projects. These included the exploration of 10/9, 27/9, F80 and Pozu Jenga.


The Ario 2000 expedition was incredibly successful, finding some of the most significant cave passage of recent years.