62 Figure 4 - Time-dynamic water stress ratio for South American porphyry copper production under the IEA STEPS scenario, 2030–2050, TaiESM1, SSP2-4.5. Analysis of the sequence of maps indicates that 54 deposits, representing 60% of annual copper production, are located in grid cells where the mining water stress ratio exceeds 20% in 2030. By 2050, it’s 52 deposits, representing 62% of production. Spatially, the highest stress values occur along the western coast of South America, with pronounced concentrations in northern and central Chile, reflecting the combination of concentration of large deposits and limited extractable water in these regions. The findings highlight changes in both the spatial extent and intensity of water stress over time. 4. IMPLICATIONS FOR MINING SYSTEMS AND DECISION-MAKING Linking climate-informed water availability with deposit-level copper production highlights regions and periods where water may constrain extraction. The results for South American porphyry copper (Figures 2–3) show that 25% of deposits are located in grid cells where mean water demand exceeds mean extractable water under the SSP2-4.5. Time-dynamic stress maps under the STEPS scenario (Figure 4) reveal persistent hotspots and emerging constraints as production schedules evolve. These insights enable early identification of locations where water could act as a limiting factor, supporting more realistic assessments of future supply feasibility. The analysis also indicates that production scheduling based solely on ore grade may not be sufficient. Incorporating water availability and consequently water sourcing costs into scheduling decisions appears increasingly important, as it can influence which deposits can be activated to meet demand without exceeding locally extractable water and remaining economically viable. Accounting for water constraints alongside grade could improve the robustness of future production plans, particularly in arid regions where water scarcity is pronounced.
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