Grotte de Milandre

Useful Information

Dimension: L=10,520 m, D=135 m.
Guided tours:  
Bibliography: I. Müller, W. Stiefelhagen, R.A.M. Intchi (1995): Réflexions sur les résultats obtenus par l'enregistrement en continu des pramètres géophysiques, électromagnetiques (VLF-EM) et magnétiques, pour l'exploration hydrogéologique des aquifères karstiques (Grotte de Milandre, Jura, Suisse), Bulletin de la société Neuchateloise des sciences naturelles, 118: 109-119.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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The Grotte de Milandre is located near Boncourt, right at the border to France. It was named after the Tour de Milandre (Milandre Tower), the last remains of the former castle Milandre, which stands on a cliff above the Allaine river. This castle was built in the 13th century by the Earls of Montbéliard, but was destroyed 1674 by Marschall de Turenne after the Jura was occupied by French troups.

The cave of Milandre is famous for its speleothems, and has also a cave river which is used for water supply. It is often mentioned as one of the longest cave systems of Switzerland, which is actually outdated. This cave is a big cave with a length of over 10 kilometers, but there are cave systems in Switzerland like the Hölloch and Sieben Hengste which are close to 200 kilomteres.

This cave was used for numerous scientific researches over the last decades. There are numerous scientific papers on the cave including cave climate, examination of the influence of cave tourism on the carbon dioxide level and so forth. Pretty close to Boncourt the trans Jura motorwas is built. It connects Belfort in France with Porrentruy in Switzerland, right across the Jura. But although it was rather likely that karst features would be hit during the construction, it was known from the cave survey that the motorway would cross the cave at a point where it was covered by about 40 m of rocks. So it was necessary to do the construction with all necessary precautions. Both the contruction of motorway and a tunnel, and the use of the motorway afterway had to be taken into consideration. This is one of the good examples how an organization of speleologists like the Schweizerisches Institut für Speläologie und Karstforschung (ISSKA) is able to help normal civil engineers in safe constucting in karst areas.