Infrastructure organisations must reduce carbon emissions, improve resource efficiency, and maintain service performance across large ageing asset portfolios. However, circular-economy interventions in infrastructure are often organised around individual projects, limiting understanding of where material and carbon impacts accumulate at portfolio level. This paper develops a top-down portfolio-level modelling approach to support circular-economy prioritisation in flood-risk management infrastructure. The study integrates public asset-register data with organisational carbon and material-flow datasets to identify lifecycle, asset, and material hotspots across a distributed infrastructure portfolio. Using 415 asset-level carbon records and 5486 material-level records, the analysis estimates whole-life carbon distribution across asset classes and maps material inflows across material–asset combinations. The findings reveal a strong concentration effect: a small number of lifecycle stages, asset types, and materials account for a disproportionate share of portfolio-level impacts. Replacement carbon emerges as a major whole-life contributor, while walls, embankments, and channels dominate asset-level emissions, given the organization context. At the material level, soil/clay, steel, concrete, and stone represent key hotspots, showing that circular-economy strategies should address both high-carbon materials and high-material mass earthworks. The paper contributes a portfolio-level screening approach that shifts circular-economy analysis from project-level optimisation to portfolio-level prioritisation.

This paper proposes a conceptual frame shift in how we think about mineral coproduction and the conditions that can reorientate the goals of the existing extractive paradigm. Mineral coproduction is the process of extracting multiple minerals from the same resource, minimizing harmful impacts of creating a new hole in the ground and promoting resource efficiency. We investigate the concept of mineral coproduction through a technocultural lens, using ore-sand as a case study that views geologies of extraction through social science theories, particularly translation theory. Ore-sand is an emerging circular economy alternative to naturally occurring sand, extracted and processed as a companion product to metallic ore minerals, at a time when both bulk minerals and critical (and other) metals are in escalating demand for the energy transition. We ask whether the ore-sand subclassification of manufactured sand (crushed rock) might reduce negative socio-environmental impacts of sand extraction overall, by consideration of other forms of sand extraction, including from aqueous environments. Three systemic criteria are proposed to place sustainability agendas centrally in geotechnical discourse and thereby examine whether mineral coproduction (e.g. ore-sand) constitutes a paradigm shift. The criteria are: approaching socio-environmental revaluation; characterizing geological cultures of extraction; and considering geo-anthropogenic limits to extraction. For each criterion, acts of translation are needed to embed care into paradigm reorientation. Socio-ecological care that is culturally bounded is critical to our future. We argue that conceptualizing a paradigm of care shifts how we act around future resource exploitation, differentiating between greenwashing and positive innovations.