Abstract: Through the building of a digital ore deposit model, the authors evaluated the present exploration situation and potential economic value of the rare mental mine in Koktokay No.3 vein of Xinjiang. The digital ore deposit model consists of two parts, namely 3D model of geological bodies and 3D grade model of borehole data. The former part, based on geological profiles, terrain model and prospecting lines, vividly represents the spatial pattern and inner structure of the ore deposit by using the software Micromine and the 3D visualization technique. The latter one, based on drilling test data, shows the spatial distribution of anomalous metallogenetic elements after 3D interpolation of elemental grades in the model scope by using geological statistic method. With the combination of the two models, the authors assessed present exploitation status of the mine and delineated the remnant ore bodies. The “Isosceles Triangle” method is proposed in this paper for estimating the potential ore recourses. Studies shows that, although the “bell-shaped” ore bodies have been fully exploited, there still exist exploitable large-size ore bodies with high economic value in the gently-inclined southern part of the “bell-shaped body”, and the potential resources of beryllium oxides are approximately between 822.69 and 1992.41t.