This study aims to understand the emergence of bottom-up social practices in shadow networks in the context of an industrial disaster. The empirical focus involves the Guarani and Tupinikim indigenous people, victims of the Fundão tailing dam rupture, one of the world’s greatest socio-environmental disasters. We adopted a qualitative approach to identify the indigenous shadow network’s agency, resistance mechanisms, and resilience activation. We interpret indigenous resistance as a way of fighting for their existence, with mechanisms crafted by collective deliberation and community mobilization. We identified the mining industry’s efforts to divide resistance and how the indigenous shadow network rebuilt resistance mechanisms through activating resilience based on indigenous values, interconnected leaderships, and social memory from their ancestral land. We thereby advance in understanding the indigenous shadow network’s agency that allows managers to intervene with on-ground actions to maintain or enhance resistance and resilience in the context of organizational studies.