Global decarbonisation pathways depend on secure supplies of critical minerals, yet the expansion of mining activity increasingly hinges on societal acceptance and the maintenance of a social licence to operate. This paper synthesises findings from two large-scale national studies, the Australian Attitudes to Mining Survey 2024 (Moffat et al, 2024) and the Canadian Social Acceptability Barometer for the Mining Sector (Moffat et al, 2025), to examine public attitudes toward mining and their implications for critical minerals development in resource-rich democracies. Together, the surveys capture societal sentiment from more than 11 000 respondents and provide a rare, comparable evidence base across jurisdictions with significant critical minerals endowments. Both studies demonstrate strong strategic-level support for mining, particularly for critical minerals underpinning the energy transition. Majorities in Australia and Canada view such minerals as essential to national prosperity and the achievement of net-zero objectives, and generally prefer secure domestic supply. However, this support is explicitly conditional. Persistent concerns regarding environmental impacts, benefit-sharing, procedural fairness, and trust in mining companies continue to constrain social licence, particularly at the local and project scales. In both countries, trust consistently lags acceptance, underscoring that broad societal approval of critical minerals extraction does not translate automatically into consent for specific developments. Beyond the substantive findings, this paper highlights the value of systematically measuring, analysing and hence understanding societal sentiment across jurisdictions key to critical minerals production. Replicable engagement science methodologies enable benchmarking of trust, legitimacy and acceptability, providing early warning of social risk and opportunities for adaptive governance. Securing long-term access to critical minerals will therefore require sustained investment in social performance and evidence-based engagement informed by continuous sentiment monitoring.