Under consideration of today´s circumstances the usage of a power generation plant that applies a deep geothermal probe built from the surface is not efficient. This study is part of the project MinTHERM and researches the usage of a deep geothermal probe that is sunk from an already existing underground infrastructure. After an introduction describing deep geothermics in general, the conditions of the regarded deep geothermal probe situated in “Magnesitbergbau Breitenau” are presented. The next two parts cover the simulation of the cooling performance of the rock mass surrounding this probe. In the first part, the application of the numeric calculation in the finite element program ABAQUS is verified through two comparative calculations. The actual simulations of the deep geothermal probe are then described and executed in the second part. Within these simulations, calculations of a model which either does or does not consider a casing are performed. Furthermore, parameter studies with diverse variables such as the borehole radius, the extracted heat, as well as different rock mass parameters are executed. The borehole wall temperatures reached within these simulations show that under the provided conditions a deep geothermal probe does not deliver a sufficient heat volume to run a commercial power generation plant.