It won’t have a very fancy name or with a lot of hook, but the Great Well MDTE, located in the Cantabrian municipality of Ruesga, has the honor of being the largest vertical well in Spain. It was discovered in 2016 by speleologists from the Club Cántabro de Exploraciones Subterráneas and the Espeleo Club Ábrigu (and thanks to some shepherds) and its history is most interesting.
It is a well with a confirmed depth of 435.92 meters. And how much is that? To give us an idea, the Eiffel Tower is 324 meters high (if we count the antennas). It is, simply put, a monstrosity of a pool.
It all started in the summer of 2016…
The story is told by the ÁBRIGU-CCES cavers themselves. We have to go back to 2016, the year in which the exploration groups dedicated themselves to investigating the Porracolina Karstic Massif Zone (at the eastern end of the Cantabrian Mountains). In the words of the speleologists:
It all started in the summer of 2016 (06/29/2016). After a prospecting trip in which several interesting cavities were located, in an area close to the Cabañas del Mortero, it was possible to record small caverns close to two known chasms (Torca del Tejón and Torca de la Yusa). Subsequently, and thanks to the indication of several shepherds in the area, they indicated that one of the marked caverns, in the cold winter months, expelled a lot of air, which caught our attention.
There was definitely something there. During the following weeks it was possible to gain access to the interior. After passing the mouth and a small cat flap, there is a well of about seven meters that ends in a meander. A few meters further on, you can access the head of the well.
Thus began the first survey: throw a stone. Throwing a stone can estimate the depth of a well (time squared by gravity between two and applying corrections for air friction and temperature, humidity and speed of sound) and the first result was “50 or 60 meters”. “Then a sound appeared that was lost in the distance and after several seconds, when a new stone was being collected for another survey,” the explorers explain.
They began to install the well at -25 meters. They went down even more, to 50 meters, where there were some kind of built-in blocks. “Our surprise was enormous when we verified that these were suspended in the “air” over a huge well,” the speleologists recounted in their chronicle.
They threw a new stone and they counted “about 10 or 12 seconds” until you hear the sound of the impact of the stone against the bottom. Estimates were between 400 and 500 meters, crazy. The next day, and with more material, the speleologists installed the first 100 meters of the well. Two days, 600 meters of static rope and 57 divisions later, the speleologists managed to touch the bottom.
The well ends at the call cursed room of the Torca del Tejón. And it is curious, because this room also communicates (indirectly) with Los Pasiegos, which until the discovery of the Gran Pozo MTDE was the largest well in Spain. The MTDE thing, by the way, is a tribute to the brand of used caving material.
Imagen | Mathew MacQuarrie
