That will almost certainly be these tunnels:
[www.spiegel.de]
More from Kusch:
[austriantimes.at]
His book:
[www.amazon.de]
Interesting review, see the article mentioned at the end of it (translate with Chrome or Google toolbar). Thomas Rathgeber, in: Contributions to the cave customer and Karst in Southwest Germany 47, 2010, p. 2 (Http://science.naturkundemuseum-bw.de/files/Ueber_Erdstaelle-aus47.pdf) Kühtreiber Thomas, in: The Cave. Zeitschr. for Karst and Speleology 61, 2010, p. 137-140.
He's Austrian (or British), [translate.google.co.uk] - ignore the spelling change for his name.

Doug Weller

Director The Hall of Ma'at
Doug's Skeptical Archaeology site::
[www.ramtops.co.uk]