Until 2001, gypsum was extracted in an underground operation from the gypsum mine Preinsfeld, Austria. The initially used mining method was room and pillar mining. The mine is currently backfilled in order to protect the surface and the mine itself. Due to the former extraction on sublevels, there is still gypsum left to mine inbetween the sublevels. The aim of this master thesis is to evaluate the amount of gypsum in those sill pillars, which measure on average 4 m in heigth, and to find an appropriate mining method to extract them. The excavation method of blasting is compared to machine excavation with a roadheader. After the decision was taken in favour of the roadheader, the hauling fleet is adjusted to it. The next step is to compare the different mining methods, which are suitable for this kind of deposit. Therefore, a three-dimensional model of the possible mining methods is created by using the geology and mine planning software Geovia Surpac™. A classical room and pillar mining method is planned for different tunnel profiles and then compared to an adjusted cut and fill stoping method with backfill. After consideration of technical, economical and safety factors, the decision was made in favour of the cut and fill mining method. Therefore, a detailed study on the mine planning, mine ventilation, costs and life of mine was conducted.