The idea of embedding social licence in mining practices is attractive because it suggests a formalisation, institutionalisation, or integration of social concerns with more well-established biophysical, environmental, and economic concerns, and thereby a sensitivity to power relations. Social impact assessment can be seen as a practical framework for operationalising this social licence through reflexive social science, but it suffers when proponents misuse social science to ‘assert’ community approval. Our two case studies of proposed coal and coal-seam-gas mining in New South Wales, Australia, illustrate some differences between ‘reflexive’ and ‘assertive’ approaches to SIA and social licence. Assertive approaches tend to use data selectively and/or misleadingly in an effort to ‘prove’ high community approval, and make unsubstantiated truth claims. Reflexive approaches are methodologically rigorous, procedurally fair, transparent, inclusive, and impartial. Reflexive approaches are more likely to prevail when institutional arrangements include professional independence, leading-practice guidance, and a supportive regulatory environment.