The aim of this article is to analyse the prospects of gold mine development at Roşia Montană, with a focus on the uncertainty regarding this process. We are specifically interested in the issues associated with cyanide spill accidents and how these uncertain events can alter the cost/benefit analysis. Making use of an established methodology, we conclude that the projected gold exploitation can pose considerable risks to the environment, and that an efficient operation would imply either reducing these risks, their effect on the environment, or both. Finally, we also draw from historical knowledge regarding the ancient mine Alburnus Maior, in order to assess the viability of the modern exploitation. We conclude that the modern project could be improved by technological progress, which would seek to maximize the scale of operations, while minimizing both the risk of accidents and their impact on the environment.