Extending the reach of multi-tier sustainable supply chain management - Insights from mineral supply chains

Triadic or tetradic multi-tier sustainable supply chain management (MT-SSCM) research emerged recently to reach out towards raw material suppliers and to address their often severe sustainability impacts. This is especially relevant in mineral supply chains (SCs) which consist of a commodity chain upstream and an end-product chain downstream. To comprehensively investigate the reach of MT-SSCM in mineral SCs, the extant Delphi study brought together 44 global authors on sustainability in mineral SCs. They contributed their professional knowledge in three questionnaire rounds, which systematically identify, evaluate and contrast the sustainability challenges in mineral SCs. As a result, a generic mineral SC structure is derived and 17 major sustainability issues are identified. Moreover, the findings reveal that all but two sustainability issues need to be addressed in the upstream SC. As mineral SCs might comprise up to nine tiers, the most impactful tiers lie outside the reach of current MT-SSCM concepts, which are limited to triads or tetrads by the visible horizon or lacking power of the focal firm. We thus propose a cascaded MT-SSCM approach which links the up- and downstream SC parts. Moreover, individual focal firms for each SC part are defined, which build a direct strategic link. This link enables that tailored managerial responses can be cascaded into the respective SC parts, where the individual sustainability issues can best be addressed. This cascaded design represents a novel approach in MT-SSCM which multiplies existing concepts. Moreover, the challenges and opportunities, which the cascaded approach raises for MT-SSCM research are discussed and outlined.