Circular economy landfills for temporary storage and treatment of mineral-rich wastes

Abstract

Many countries face serious strategic challenges with the future supply of both aggregates and critical elements. Yet, at the same time, they must sustainably manage continued multimillion tonne annual arisings of mineral-dominated wastes from mining and industry. In an antithesis of circular economy principles, these wastes continue to be landfilled despite often comprising valuable components, such as critical metals, soil macronutrients and mineral components which sequester atmospheric carbon dioxide (CO2). In this paper, the authors aim to introduce a new concept for value recovery from mineral-rich wastes where materials are temporarily stored and cleaned in landfill-like repositories designed to be mined later. The time in storage is utilised for remediating contaminated materials and separating and concentrating valuable components. It is proposed that this could be achieved through engineering the repository to accelerate ‘lithomimetic’ processes – that is, those mimicking natural supergene processes responsible for the formation of secondary ores. This paper summarises the concept and justifications and outlines fundamental aspects of how this new concept might be applied to the design of future repositories. The proposed concept aims to end the current ‘linear’ landfilling of mineral-rich wastes in favour of reuse as aggregates and ores.