Ta and Nb are considered critical raw materials due to their properties and potential applications in a wide range of sectors. This study deals with Sn-Ta-Nb minerals from the Penouta mine (Orense, Spain), the only active mine in Europe producing tantalum minerals. These minerals are obtained from mining waste accumulated during old mining operations in tailing ponds. The industrial processing flowsheet is based on successive gravimetric stages followed by low intensity magnetic separation to reduce ferromagnetic contaminants. A Sn-Ta-Nb concentrate, with grades between 35–45% Sn and 4–7% Ta2O5 and Nb2O5, is obtained in this stage with plant recoveries around 60–70%, respectively. A chemical-mineralogical characterization by size fractions, XRF and XRD was carried out to implement a size classification stage in the processing plant. The finest fractions, containing higher grades of well-liberated Sn, Ta, and Nb minerals were utilized as the feed for dry high intensity magnetic separation (DHIMS) multifactorial tests, while coarse fractions were regrinded to maximize performance. The favorable results obtained in these tests demonstrate that two products with commercial quality can be obtained: a cassiterite concentrate with grades between 70–78% SnO2 and a tantalite-columbite concentrate with grades ranging between 12 and 14% Ta2O5 and Nb2O5, while also increasing the overall recovery of the plant.