A process systems approach to life cycle inventories for minerals: South African and Australian case studies

In this paper, we present a process synthesis approach to the development of Life Cycle Inventories (LCIs) for production of minerals from primary ore bodies, based on a heuristics-driven flowsheeting methodology. Technologies are specified to a level of detail consistent with information availability and mass balance closure. This approach enables the creation of flowsheets for all minerals processing activities using a “cradle-to-gate” system boundary, from which it is possible to generate LCIs using accepted practices for the mapping of resource flows and emissions onto a profile of environmental burdens. In this work, LCIs are presented only for the foreground system (i.e. the flows from background systems, such as electricity generation, are documented but their environmental burden profile is not included in the LCIs reported). This method allows for the detailing of these inventories on a commodity, sector, or geographic (regional) basis. The approach has been demonstrated for all sub-sectors of the Australian and the South African minerals processing industries. A case study of the gold sub-sector in each region is presented in some detail, in order to highlight the key features of the approach and the usefulness of the LCI profiles generated. The potential for this approach to support comparative technology assessment and sub-sectoral performance is demonstrated for the copper sub-sector. Some indication of the value of the approach to assist in company benchmarking is presented. The performance of all key sectors, namely coal, gold, non-ferrous metals, ferrous metals, uranium, platinum group metals and mineral sands, though not detailed here, is available on our on-line data-base.1. This information is used to develop an aggregated picture of minerals LCIs for the minerals processing activity in Australian and South Africa.