Coltan is one of the main ores for obtaining tantalum and niobium, two elements with very particular physicochemical characteristics and of great interest for technological development since the 20th century (Hughes et al. 2011). The concentrations of uranium and thorium in Venezuelan coltan samples, previously measured by the Nuclear Physics Laboratory of the Simón Bolívar University (LFN-USB), and the description of some alluvial deposits in the Parguaza region (South of Venezuela) show the potential feasibility of locating superficial mineral deposits using gamma ray spectrometry by mapping the radiation associated with U and Th contained in these minerals. In this work we explore this possibility by using a high-density scintillator detector (BGO 3"×3" Crismatec Scintibloc 76S76). Coltan samples were used on a test field conditioned to emulate a shallow alluvial deposit, as those observed in some areas of the Parguaza region, obtaining that for detailed prospecting a 2.5×2.5 m2 spaced survey grid using a BGO detector is effective in detecting significant quantities of coltan (kilograms), even at a depth of 40 cm (depth at which artisanal extractions have been described in recent years). The need to prioritize the quantification of thorium and especially uranium was also evidenced, using their more energetic emission lines.