mass falls in the Wachau-Danube Valley (Bohemian Massif

not yet proved possible to find the finances necessary to fund an existing, well-defined remedial concept based
on the cutback of a total volume of 369 000 m³, to be realised by open mining over a period of several years.
The concept in question would provide for a total cutback of all bedding planes which had been undercut by
quarrying. The resultant cataclinal slopes above and laterally from the former quarry would extend the
longitudinal surface area of mining considerably, dividing the whole valley flank into berms and quarry faces.
In Dürnstein the slope geometry between the foot of the rock face and the railway track was redesigned, by
constructing an eight metre high protection dam using debris from the failed rock mass. It was thus possible to
construct a new reservoir to accommodate further rock-mass falls combined with a 150 metre long and up to
eight metre high protection dam without having to transport any construction material to or from the site. The
protective effect of the dam was improved considerably by redesigning the slope geometry in the transport
and deposit area of possible future rock-mass falls and creating an absorption bench at the foot of the rock
face. Additionally, a rockfall protection kit was installed (Fig. 16).
Fig. 16 Geomorphological situation in the former quarry at Dürnstein.
This was not enough, however, as major failure of certain larger parts of the rock face, especially in the upper
sections, could still result in partial damage to the dam. Moreover smaller blocks could bounce over in this case.
Therefore these potentially hazardous parts of the rock face were monitored. At the same time, a long-term
remedial concept has been devised for cutting back these parts of the rock face by blasting. This concept was
implemented in summer 2011, removing a total volume of more than 5000 m³.
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