ABSTRACT
The significant difference between the solutions offered by “DBT” and “Sandvik-Voest Alpine Bergtechnik” apart from the main idea, is the type of tool applied. In case of the ARM 1100 asymmetrical discs have been applied. This way the cutting technique has been replaced by a technique of undercutting by discs. In figure #6 the diagram shows the commonly known differences between symmetrical and asymmetrical discs (Hinterschneidttechnik. Wirth maschinen und bohrgeäte-Fabrick GmbH). This winning method differs quite significantly from the standard one based on the use of cutting tools.
