Excavations underground research workResearchers working underground are able to use only few of the techniques available to researchers working above ground. Moreover, they are often very restricted in their choice of areas to investigate.
Difficulties of mining archaeologyArchaeological investigations in a mine are subject to considerable limitations. A number of crucial standard methods cannot be used belowground. This applies in particular to the prospection method normally adopted to assess the size of a site, its environment, or the extent of a prehistoric settlement zone. Prospection is aimed at the systematic, large-scale recording of the spatial distribution of finds within a finds zone, or the distribution of sites in the landscape. Various techniques are available for this purpose: direct landscape survey by people (fieldwalking, for example) measurements of the physical properties of the soil (georadar, geomagnetics), and aerial archaeology. Inside the mountain however, we have to rely on small, arbitrary sections; we can only gain insights in relation to the locations worked since 1311. Georadar and geomagnetic measurements are impossible underground in the salt deposits. This means that the situation in the mountain is known only at the spots that were worked on a large scale by modern mining.There is no information whatsoever about prehistoric remains in places that have not been mined in modern times. We are thus not in a position to say anything about the upper 20 to 30 metres of the salt deposit, although these layers close to the surface would be of particular archaeological interest. It is in these layers that we may expect to find evidence of the oldest mining activities. These areas were not exploited in the modern period, because so close to the surface no rock matrix existed in which a successful leaching plant could be run. The tools that can be used in mine excavations differ from those used aboveground. Since the rock pressure has reclosed old galleries, and since the detritus of the old working floor has subsequently been compressed back into solid rock, digging can only be done by pneumatic drills, not by shovels and trowels. The documentation of finds also has to follow a different path.(Reschreiter, H. Kowarik, K. Loew, C.)