In the Montafon you can find a number of sinkholes in the natural landscape like the ones you see in the woods on the Kristberg.  Not all of them are from mining, though.  In the area around St. Anton, for example, the indentations are from caved in gypsum holes that were washed out by water.  They have been named Gipsdolinen or Gypsum dolinas.  Traces of pre-historic mining were discovered while archaeological investigations were being carried out in the Silbertal.  The oldest mine in the region can be found on the Kristberg.  If they are observant, hikers can make out the traces that mining has left behind.  In the framework of an interdisciplinary research project that has been running since the year 2000, besides the research being done on the history of vegetation on the moors of Bartholomaeberg and Silbertal other archaeological research is being carried out with the goal of finding evidence of mining in the Bronze Age. 

In the framework of this research project, extensive prospecting and inspections were not only carried out to explore the moors, but also to look at the known indications of mining to see if they held clues or traces of “old” mining that is older than the mostly well preserved and easily recognized mining relics from the high and late middle ages.  The first archaeological digs were begun in 2003 in the back of the Silver Valley in the Gafluna Valley, in a small open pit mine with traces of fire.

In the summer of 2005 another archaeological survey was done on the Kristberg in a sink hole field (ore mining pit field) near the Kristbergsattel lift which would determine the age of the mining relics.  To do this, they dug a long profile ditch through two sink holes in order to determine the shape and depth of these small mining pits.  The so-called sink holes are close-to-the-surface mining pits, where a short shaft was driven into the ground and the discarded dirt, or tailing was deposited in a circle around the shaft.  What they were mining for was iron ore.  Coal was discovered on the old surface during the excavations and sent in to be dated.  Two radio-carbon datings done in Vienna dated it back to the 11th or 12th centuries – the high medieval period.  These are then, the oldest archaeologically proven traces of mining in the Montafon and also in Vorarlberg.  Even so, the mention of 8 iron melting furnaces in the documents concerning reclaimed Grishon-Rhaetian land from the year 842 AD indicate an even longer history of mining in the area of Bludenz and Klostertal and the Montafon.  The goal of additional archaeological excavations is to find even older traces of mining – perhaps from as far back as the Bronze Age.   

In connection with prospecting and archaeological excavations, slag, slag heaps or smelting places will be looked for.  Their sights will not only be set on copper and the bronze age, but also on the question of how iron ore was used in Celtic times from which a few individual archaeological finds come like two lance heads and a clasp.  There were also intensive settlements in the moors and on the settlement hill in the Friaga Forest in Bartholomaeberg.  In 1966, with the iron ore artefacts found in Bludenz-Unterstein in mind, the former director of the Vorarlberg State Museum, Elmar Vonbank, expressed his notion that the iron ore from the Davenna Stock (that is - Klostertal, Silbertal and Bartholomaeberg) could have been mined and utilized as early as the Celtic times.