National and international deliberations about whether the global mining industry should be permitted to use the earth’s seas as mine waste dumps are not decided on the basis of independent scientific data from past or existing sites. Nor is a critical lack of scientific knowledge about the deep sea environment and about the long‐term consequences of marine dumping triggering the precautionary principle for proposed projects. Rather, governments make decisions on submarine tailings disposal (STD) on a mine‐by‐mine basis, in a context of contested scientific claims, considerable political and economic pressure, and, sometimes, contravening or amending existing legislation to allow a project to proceed. These decisions provoke complex social processes that commonly involve: local opposition; political conflict; regulatory and legal challenges; powerful industry lobbies; international financial institutions, and resource‐hungry states. STD projects engender controversy in developing countries, such as Papua New Guinea (Divecha 2002; Shearman 2002a), Indonesia (Edinger 2012; Glynn 2002) and the Philippines (Coumans et al. 2002; Coumans and MaCEC 2002), but also in Canada (Cultural Survival 1982) and Norway (Kvassness et al. 2009). This paper examines cases drawn from the Philippines, Canada and Papua New Guinea to illustrate common themes that arise in conflicts surrounding STD mine projects.