This presentation explores the significance of copper to the making of Chilean modernity following a material semiotics perspective. It does so through an inquiry into the development of copper smelting and its role in the making of environmental quality and human rights standards in Chile. Copper appears not just as a passive piece of matter or a highly standardised commodity; but also as a recalcitrant actor, with multiple affordances, involved in complex transnational circuits, and capable of setting life conditions to Chilean population based upon its own mineral existential needs. The presentation draws upon different sources collected during six months of fieldwork in Chile, including interviews, administrative archives, media articles and government proceedings. The first part of the presentation briefly outlines the last sixty years of industrial development in Quintero Bay, pointing to the role of copper smelting in driving this process. The second part looks at how the interest of copper were represented during the negotiation of air quality standards conducted by the Chilean Ministry of the Environment between 2000 and 2013. And finally, the third part examines the reports that have been developed by different agencies claiming human rights violations in Quintero Bay. By following the spatial assemblages of copper production and the mobilisation of copper interests, this presentation seeks to shed light on the moralities of copper mining development and it’s role in producing a distinctive modernisation process.