Starting in 2016, in the Côtes d’Armor district, in French Brittany, two natural resources extraction project face strong local mobilizations. The first one is the Loc-Envel mining project, in the countryside, and the second one is a shell sand extraction licence, on the coast. Although those two struggles are rather close to each other, they take different shapes : while the mobilization against the Loc-Envel mining project takes the form of a flexible coalition, the one against the shell sand extraction is structured in a coalition organisation (Staggenborg, 1986). How can we explain these differences in such a small area ? In order to answer this question, this article looks at the role of local heritages and framing in the shaping of environmental conflicts. Thereby, we find a counter-expert approach on the coast and a territorialized one in the countryside, while the criticism of extractivisme (Bednik, 2016) remains marginalized.