To stop global warming at well below 2° C, the bulk of the world’s fossil fuel reserves will have to be left in the ground. Coal is the fossil fuel with the greatest proportion that cannot be used, and various advocacy groups are campaigning for a ban on the opening of new coal mines. Recently, both China and the USA implemented temporary moratoria on the approval of new coal mining leases. This article examines whether these coal mining bans reflect the emergence of a global norm to keep coal under the ground. To that end, we review recent coal mining policies in the four largest coal producers and explain them comparatively with a framework based on interests, ideas and institutions. We find that the norm of keeping coal in the ground remains essentially contested. Even in those countries that have introduced some form of a coal mining moratorium, the ban can easily be, or has already been, reversed. To the extent that the norm of keeping coal in the ground has momentum, it is primarily due to non-climate reasons: the Chinese moratorium was mostly an instance of industrial policy (aiming to protect Chinese coal companies and their workers from the overcapacity and low prices that are hitting the industry), while the USA’s lease restrictions were mainly motivated by concerns over fiscal justice. We do not find evidence of norm internalisation, which means that the emerging norm fails to gain much traction amid relevant national actors and other (large) coal producing states. If proponents of a moratorium succeed in framing the issue in non-climate terms, they should have a greater chance of building domestic political coalitions in favour of the norm.