Abstract
The Camaquã Mines, located in the municipality of Caçapava do Sul, Rio Grande do Sul State, southern Brazil, constitute a historical mining district of recognized importance within the context of Brazilian copper mining. The district is hosted within the Neoproterozoic volcano-sedimentary succession of the Camaquã Basin. Since the discovery of oxidized copper minerals in 1865, the district has undergone successive cycles of exploration, expansion, and mine closure, reflecting the technological, economic, and institutional evolution of the Brazilian mining industry. The legacy of these activities resulted in the accumulation of substantial volumes of tailings and waste rock which, in light of the growing global demand for copper driven by the energy transition and the increasing interest in critical and strategic minerals, represent materials that may be reassessed as potential secondary mineral resources. Within this context, the present study revisits the historical evolution of the Camaquã Mines and integrates historical, geological, metallogenetic, and mineralogical information to support a preliminary assessment from the perspective of the circular economy.
The methodology was based on the compilation and integration of geoscientific information, the contextualization of the district within the Brazilian copper mining sector, and the interpretation of metallic associations characteristic of copper deposits. The results corroborate the polymetallic character of the mineralization, highlighting associations among Cu, Zn, Pb, Fe, S, Au, Ag, and other elements consistent with the parageneses described for the district. The integration of these datasets enabled the establishment of criteria for the selection and prioritization of a target area for future geochemical, mineralogical, technological, and environmental investigations, with emphasis on evaluating the resource potential of tailings and waste rock. The results indicate that the reassessment of mineral deposits should extend beyond the conventional evaluation of primary mineral resources by incorporating an integrated assessment of metallic associations and materials remaining from historical mining activities. Such an approach broadens the prospects for future evaluations of coproducts and other elements of economic interest, including critical minerals, rare earth elements (REEs), and other strategic elements, where geologically compatible with the mineral systems under investigation. The Camaquã Mines constitute a representative case study demonstrating how the integration of historical and geoscientific information can guide the reassessment of historical mining districts and identify opportunities for the sustainable utilization of mineral resources, including the potential reintegration of residual materials into the production cycle, subject to appropriate characterization and technical, economic, and environmental feasibility assessments. Any future mining cycles within the district will depend not only on global market conditions but also on integrated evaluations of both the primary mineralization and the remaining materials, thereby contributing to more efficient resource utilization, the reduction of environmental liabilities, sustainable mining practices, and long-term mineral supply security.