Estimation of the potential of landfill mining and exploration of metal-enriched zones

Abstract

Since the Industrial Revolution, people have exploited natural resources to manufacture products. Many of the products have later been disposed of in landfills and the like. The aim of this study was to determine the contents and chemical forms of valuable rare metals in landfills and to identify the metal-enriched zones in landfills using non-destructive prospecting methods. Box experiments were performed using four mixtures of sand and iron sulfide particles, and excavated waste samples. Field prospecting studies were performed at an industrial landfill site. As a result, it is possible to establish a grading system for elements based on the maximum contents in the fill, and the condition in the fill is found to potentially affect the metal distribution. In addition, investigations for rare metals coexisting with iron sulfide were performed at each target site. This allowed zones with high rare metal contents in the fill to be identified in a non-destructive manner. Based on the above approach, a basic evaluation of a landfill site that could be used as an “urban mine” was accomplished.