Visitor numbers to the slag heaps in the Franco-Walloon mining area has increased significantly. The latter have gained in popularity by focusing on their ecological, historical and social interest. This gives rise to several challenges, particularly with regard to their reception capacity and sustainability. Indeed, the slag heaps, as industrial sites, were not built to receive the public and uncontrolled use could jeopardise the economic development of the territory by preventing access to sites that have become dangerous. The cross-border Destination terrils project aims to support tourism and the economic development of this territory while preserving the integrity and heritage of the sites for sustainable development. To do this, a series of indicators are initially developed (visitor numbers, biodiversity, remains of the activity, etc.). In a second step, reception schemes are developed to guarantee the sustainability of access to the sites. Finally, an Internet portal and digital tools are being developed to ensure access to as many people as possible.