Igor Díaz Lopez has been a member of Sintracarbon for 30 years and is currently its treasurer. The trade union fights for the rights of workers of Cerrejón and the protection of the freedom of association. Following a meeting in Bogotá with members of Dutch trade union, CNV, the Dutch Embassy and executives from Cerrejón, Drummond and Grupo Prodeco-Glencore where they discussed the future of coal mining in the country, Igor Díaz received a pamphlet signed by paramilitary group "Aguilas Negras" threatening him and other colleagues and accusing them of being guerrilla group members.