Global decarbonisation and electrification are driving growth in copper demand while increasing scrutiny of metal’s embodied emissions and supply chain resilience. As a foundational energy transition metal underpinning renewable systems, electrification, transmission infrastructure and low carbon technologies, copper plays a critical role in broader critical minerals ecosystem. This paper develops a transparent techno-economic framework to quantify cost-emissions trade-offs along the primary copper value chain, covering ore extraction and concentration, smelting and anode casting, electrorefining, rail transport and seaborne shipping. The Python-based model links mass and energy balances with capital, operating and carbon costs under user-defined ore grades, power mixes, fuel choices, carbon prices and logistics routes, reporting results per tonne of contained copper. A fossil-intensive business-as-usual configuration, representative of current global practice, yields mine-to-export costs of about US$4900 t-1 Cu and emissions near 5.9 t CO2-e t-1 Cu. We then design ‘green corridor’ portfolios that combine higher-efficiency comminution, renewable power purchase agreements, electrified stationary loads, lower-carbon fuels for smelting and logistics, and optional hydrogen or e-fuels for premium low-carbon products. Under the lowest-emissions portfolios, levelised costs for cathode exports fall to around US$3900–4000 t-1 Cu (≈20 per cent reduction) while emissions decline to ≈1.6 t CO2-e t-1 Cu (≈75 per cent reduction), implying an effective abatement cost of roughly -220 to -230 US$ t-1 CO2 at the mine-to-export scale. The results identify three strategic levers for copper supply chains: 1. Decarbonising mining and stationary electricity through low-cost renewable power. 2. Targeting hydrogen and e-fuels to hard-to-abate processing and transport segments. 3. Leveraging regional resource and infrastructure to determine where value is captured along the value chain, particularly the shift from concentrate exports to onshore cathode. While demonstrated for copper, the modular framework is transferable to other critical minerals and strategic materials (Li, Ni, CO, REEs), providing practical decision-support platform for low-carbon, resilient mineral supply chains.