The demand for valuable minerals and the foreseen risk involved in its supply in world-scale market, imposes conditions for the industry to proceed with the development of alternative mineral sources. Old tailings may represent a solution for providing some valuable minerals as a secondary resource, and simultaneously reduces the environmental and social liabilities of abandoned dams. Re-mining of tailings is a robust project and requires a comprehensive study concerning the availability and the quality of these new mineral resources. The European Union has considered tungsten as a critical raw material and Portugal has a historical background of mining this valuable heavy metal. Therefore, a Portuguese former tailings dam was considerable for the potential recovery of some minerals. Constituting a case study in an Era-Min project called: REMinE, taking into account social, environmental, and economic aspects. The study area was sampled at two different levels. Samples were taken and analysed for tailings properties characterisation. Statistical analysis showed some amounts of heavy metals such as arsenic, cadmium, copper, mercury and tin. Geochemical data was applied to a geostatistical methodology seeking the knowledge of the metals spatial distribution on the tailings. This paper aims to provide a technical feasibility study in the assessment of re-mining ore minerals from tailings. It is expected that the recovery of the tailings existing in the Cabeo do Pio dam may provide a significant amount of tungsten and zinc. The re-mining of metals zones and hydrometallurgical re-processing research was suggested through geochemical and granulometric characterisation. CITATION: Figueiredo, J, Cristina Vila, M, Gomes, P V, Martins, D, Futuro, A, Gis, J, Lurdes Dinis, M Leite, A and Fiza, A, 2019. Can old tailings disposals become mineral resources? A Portuguese case study, in Proceedings Mining Geology 2019, pp 459465 (The Australasian Institute of Mining and Metallurgy: Melbourne).