| Title | Exploring Geothermal Potential: Drilling and Pumping Tests at the Dannenbaum Mine |
|---|---|
| Authors | Dimitra Teza, Dirk Boernecke, Kirsten Appelhans, Felix Jagert, Jochen Raube, Erik H. Saenger |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | The Stadtwerke Bochum Holding GmbH intends to establish a geothermal facility at the Mark 51°7 site in Bochum, Germany, utilizing mine water from the abandoned Dannenbaum coal mine for heating and cooling purposes. From 2021 to 2022, drilling operations were conducted to explore the 4th and 8th levels of the Dannenbaum mine, with one well drilled for each level. The first well, GT2, was drilled to a depth of 343 m into the 4th level drift, while the second well, GT1, was drilled to 864 m into the 8th level drift, starting from the same site. In both wells, a sudden drop in water level and a loss of weight on bit at the anticipated depth indicated a successful intersection with the mine galleries, which are only 3 m high. To further investigate the hydraulic connection to the mine, pumping tests were designed and implemented in 2023, involving both wells and using a 300 m deep pump. The tests demonstrated that the mine is hydraulically accessible and that targeted operational flow rates of up to 160 m³/h can be achieved with only minor differential pressure. Additionally, despite the similar geometries of the seams, notable differences in the hydraulic properties of the wells were observed. In our presentation, we will provide insights into the drilling operations and discuss the results of the pumping tests. The geothermal facility is expected to begin commissioning by the end of 2025. This work was part of the D2Grids project, supported by INTERREG Northwest Europe funding. |