Upstream: Extraction, processing, and manufacturing

The roots of the projected supply constraint lie upstream, and they are structural rather than incidental. The model incorporates copper's well-documented decline in ore grades through the projected increase in the ore-to-metal ratio (see Chart nine below), showing that progressively more rock must be mined to produce the same amount of refined copper. As ore grades fall, the water and energy required per tonne of copper also increase, regardless of overall production volume.

The same dynamic generates increasing volumes of structural waste. As efficiency declines, the material moved but not converted into usable metal—including tailings, slags, and other mining waste—grows as a byproduct. In major producing regions, these waste streams are already among the largest generated by any industrial activity.⁵⁸ While circular strategies cannot reverse declining ore grades, they can improve recovery and create opportunities to repurpose tailings and slags that would otherwise be lost.⁵⁹

The refining stage adds a further layer of complexity that is not captured by the aggregate material flows alone. Copper ore is processed through two principal routes—pyrometallurgy and hydrometallurgy—which carry distinct environmental trade-offs. The former is characterised by high energy intensity, while the latter is considerably more water intensive.^{60 61} As average ore grade continues to decline, a greater share of production may shift towards leaching (hydrometallurgical processing), increasing water demand in regions already experiencing water stress. Refining capacity also mirrors the geographic concentration of extraction, with a small number of countries accounting for the majority of global refining.⁶² As a result, the supply risks associated with geographic concentration are carried through the refining stage rather than being reduced by it.

Chart 10 shows that material losses continue beyond refining. Losses occur at both the semi-fabrication and manufacturing stages, although it is recognised that manufacturing consistently accounts for the larger share.⁶³ Unlike refinery losses, these losses arise from processing rather than geology—representing an opportunity to improve material efficiency within existing manufacturing systems, independent of how much refined copper is available. That said, manufacturing capacity itself is not the constraint: manufactured output follows the same rise-then-decline trajectory as upstream refined supply, meaning output is ultimately limited by how much refined copper is supplied, not by the manufacturing system's ability to process it.