The War of the Pacific (1879-1883) between Chile, Peru, and Bolivia marked a turning point in the political and socio-economic development of the Atacama Desert. Formerly part of Bolivia, this area came under the control and jurisdiction of Chile in 1884. This shift in sovereignty substantially altered the tri-national geopolitics, forcing the local Bolivian population to flee. The newly annexed region's rich mineral resources became subject to a mining colonization process. In 1912, the Guggenheim family founded The Chile Exploration Company and began the industrialization of the Chuquicamata copper mine. Located in the heart of the Atacama Desert, this was the world's largest copper mine during the twentieth century. Although the local Bolivian population had fled the Atacama Desert following the war, many returned to work in the Guggenheim mine almost thirty years later. Between 1912 and 1925, 239 Bolivians labeled as foreigners and "Indians" were employed in diverse production stages or subsidiary services. Bureaucratic migratory documents and newspaper archives allow us to quantify and characterize Bolivian migration to Chuquicamata. We argue that an ethnic-labor subsidiarity emerged, a historical process resulting from ethnic discrimination, expressed in the disposition and physical costs of mining work and low wages. While the war altered the mining territory of Atacama, ethnic-labor subsidiarity of the Bolivian workforce sustained the expansion of U.S. capitalism in the Chuquicamata copper mine.