At the end of 1972 he left Santiago and moved to the mining town of Chuquicamata, where he ministered to the miners and workers, and witnessed labor exploitation by the subcontractor companies. The following year a military coup would depose the Socialist president Salvador Allende and Augusto Pinochet assumed the role of dictator of Chile a year later. At the same time Puga's extreme fidelity to the Liberation Gospel and his strong sympathies for Socialism led him to being dismissed from his pastoral role in Chuquicamata by cardinal Raúl Silva Henríquez, who despite having leftist sympathies himself, deemed Puga to be too progressive and outspoken. Multiple times during the dictatorship Puga attempted to enter the National Stadium in Santiago, which was a known detention center where political prisoners were tortured, but he was never allowed inside.