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A killer cave: some examples of very rapid corrosion of gear

As said over and over again, the Grotte des Emotions is extremely muddy and the lower levels of the cave flood regularly upto 20 metres high.  We have experienced that the water/and or mud are very aggressive for all metal gear that is left behind in this part of the cave. 

We have at two occasions had problems with brand new INOX ladders that were left in the cave for +/- 3 months.  The (aluminium) shrinking that kept the bars in place, were so corroded that the bars slid down the inox cables, making the ladders unusable.   In this case, an electrolytic corrosion between the inox cable and aluminium shrinking was accelerating the process.   But throwing ladders away after only 3 months of use, is not very affordable for a small caving club!

Especially karabiners made from zicral corrode very rapidlyWithin less than a year they have become totally useless. This is really amazing. We have other caves, such as Bois de Waerimont, where zicral karabiners have been used for fixed ropes as well. After 6 years of service, they still do not represent any danger at all. 

But Grotte des Emotions is different. See some examples below. 

These examples are the living proof that:

  • you should never, ever, have trust in a fixed rope that disappears into the darkness of the ceiling of a gallery or aven... it could be fixed on rotten karabiners.
  • you should never, ever use zicral karabiners for fixed ropes.  At long term, you might kill someone that way. Only use steel ones, and if possible inox ones.

I can not explain why the water and mud in this cave attack all metal so quickly. The PH of the mud is 7, which is quite neutral!


EXAMPLE 1: A series of 12 karabiners was purchased in 1995  (manufactured in 1994) and put into to cave for a period of no longer than 12 months. Then they were replaced by steel maillon rapides.

Unfortunately, we had to thrown away all of the karabiners. As the picture clearly shows, they were already partially "eaten" by the cave!

NB: the screw of the karabiner has been removed afterwards.


Example 2 (front view ) : in Sept 1997 two divers passed the terminal sump of the cave and made a 12 metre high climb there. They left a fixed rope there, attached to two good karabiners.
Six years later, in December 2003, we continued the exploration. When prusiking up the rope, I suddenly fell down 3 metres, luckily without any injuries. The karabiner had broken.


Example 2 (back view ) : as you can say, the karabiner has been destroyed to the core by corrosion.  No wonder it broke as soon as some load was put onto it.


Example 2 (detail view ) : quite amazing, isn't it, after only six years?

But more amazing was the fact that I only fell down 3 metres, while I was already 5 metres up the rope.  How come?  Because, the second karabiner resisted and held my fall. Look at the following picture for this "magic" karabiner


Example 3 (front view ) : unbelievable, isn't it, that this thing broke my fall?  Now this is the difference between an oval (example 1) and a trapezium shaped (example 2) karabiner! Anyway, after 6 years in the cave, this thing is as rotten as the other one.


Example 3 (back view ) : the back side of this karabiner  - in fact, WHAT is the BACK or the FRONT side anyway ;-)



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