The EU funded project “CRM geothermal”, aims to establish an overview of the potential for raw materials in geothermal fluids for a large range of CRM elements across the EU and third countries. Due to its economic importance, Helium is closely monitored, in view of its relevance for possibly emerging digital applications [1]. Therefore, during a project-related pump test on borehole GWDD-001 of the Cornish Lithium Company in United Downs, Cornwall, UK from 20/06/2023 to 22/06/2023, an gas monitoring was conducted. This comprised the logging of gas composition and the measurement of the gas-water ratio during the pumping operation. Main focus was the examination of Helium content in the course of the pump test. In addition, experiments addressing the option of online-helium extraction via a membrane-based gas extraction method, were performed. A conventional gas sampling for lab-based analyses of bulk gas composition and noble gas concentration was completed as well. The results are reported here.