<p>The prehistoric hematite mines on the Hill of Tzines are located on the island of Thasos, in the administrative region of Eastern Macedonia and Thrace (Greece). The site was discovered in the 1950’ during the modern open-cast exploitation, and underwent archaeological investigations in the 1980’ and beginning of the 1990’. The research revealed the occurrence of underground mines – called T1 and T2 – aimed at the extraction of hematite. Despite the efforts made, the radiocarbon dating of the osseous samples from the site was hindered by their poor collagen preservation. However, two radiocarbon dates were obtained for the mine T1. One AMS radiocarbon date (ETH-11573, 24976 − 24021 years cal BP), together with the analysis of the faunal remains, suggested an Upper Palaeolithic age of the exploitation. However, based on another radiocarbon date (HD-8528-8509, 8985 − 8402 years cal BP), the excavators did not exclude a more recent Holocene mining phase. This paper presents the results of a novel radiocarbon dating programme that was conducted between 2020 and 2021, taking into account sample selection, preparation, and analysis. Despite the lack of collagen in most of the osseous samples, it has been possible to obtain two AMS radiocarbon ages for the mine T2. A radiocarbon date (MAMS-53686, 28431 − 27804 years cal BP) places the exploitation in a middle phase of the Upper Palaeolithic, corresponding to the Gravettian. A second date (MAMS-53688, 6398 − 6302 years cal BP), although unreliable due to the low collagen yield (0.4%), may suggest a Holocene phase of exploitation of the mine. Results are discussed in the context of Upper Palaeolithic mining in Europe, Gravettian cultural framework, paleoenvironmental and faunal evidence, early ochre exploitation in the Aegean, and alternative dating approaches.</p>