Framework for the evaluation of anthropogenic resources: A landfill mining case study – Resource or reserve?

The goal of this study is to apply the natural resource classification framework UNFC-2009 to a landfill-mining project to identify the landfilled materials as potential anthropogenic ‘resources’ (reasonable prospects for eventual economic extraction in the foreseeable future) or ‘reserves’ (current economic extraction possible), and to reveal critical factors for the classification of the project. Based on data from a landfill-mining project in Belgium, the focus of the evaluation was set on technological options and economics, with a material flow analysis quantifying relevant material and energy flows and a discounted cash flow analysis including Monte Carlo simulations, exploring the project's socioeconomic viability. Four scenarios have been investigated, representing different alternatives for the combustible waste fraction's thermal treatment (gas-plasma technology vs. incineration) and for specific stakeholder interests (public vs. private perspective). The net present values were found to be negative for all four scenarios, implying that none of the project's variations is currently economically viable. The main drivers of the economic performance are parameters related to the thermal treatment of the combustible waste fraction as well as to the sales of recovered metals. Based on required future price increases for non-ferrous metals or electricity to make the project economically viable, the scenarios resulted in different final resource classifications. Although the applicability of UNFC-2009 to landfill mining has been proven successfully, further research is needed to define generally suitable criteria for categorizing various kinds of anthropogenic resources under UNFC-2009. This will allow for fair comparisons between naturally occurring and anthropogenic resource deposits.