Union members of Los Mineros began a strike at Grupo Mexico's San Martin mine at Sombrerete, Zacatecas, on 30 July 2007, part of coordinated action at three Grupo Mexico mines over repeated health and safety failures and the company's refusal to recognise the union and honour its collective agreements. In August 2024 Mexico's Federal Board of Conciliation and Arbitration validated the legality of the strike, and the case became the first facility-specific USMCA Rapid Response Labour Mechanism panel, which found against the United States in May 2024.