Geoethics in decision-making for post-mining land use

Abstract

<p>Post-Mining Land Use (PMLU) corresponds to the new use given to the land impacted by mining activities. The decision for the new land use requires consideration and analysis regarding many technical aspects and will impact several stakeholder groups. At the same time, PMLU corresponds to what will follow after the mineral resource is exhausted (ideally), which leaves the site and communities without the biological and geological richness they had. However, although the original features do not exist, new features can satisfy all stakeholders’ needs. Therefore, PMLU decisions should be framed by geoethical thinking, embedding its principles and values in a Multi-Criteria Decision Analysis (MCDA).</p><p>Multi-Criteria Decision Analysis (MCDA) is a methodology used to analyse decisional problems where multiple, often, conflicting criteria are in place. Therefore, the most critical stage is structuring the problem under analysis. The result of this problem structuring is the definition of criteria and alternatives, considering the values of all interest groups to the decision (all stakeholders). This analysis is highly relevant in themes where local populations are affected by the decision, such as PMLU. The embodiment of geoethics thinking in this process is of essential role because the PMLU corresponds to a new land-use change that must happen due to human use of natural resources. The example of São Domingos abandoned mine (Portugal) will be used for this study.</p><p>São Domingos mine is an abandoned mine located in the Portuguese sector of the Iberian Pyrite Belt (IPB). IPB is a world-class Volcanic-Hosted Massive Sulphide metallogenic province formed in the Iberian Variscan orogeny (Paleozoic age). São Domingos’ ore was exploited throughout times, in the Pre-Roman Period (several centuries in the first millennium B.C.), Roman Period (approximately from 14 B.C. until 395 B.C.), Islamic Period, and Modern Period (between 1854 and 1966). The primary metals and minerals extracted in historical periods were silver, copper and probably gold. In the Modern Period, the main ores extracted were cupriferous pyrite, roasted pyrite, sulfur, and copper.</p><p>All exploitation periods left important features. For example, archaeological records of ancient slags with high value for local and national history and culture are preserved from the pre-roman and Roman periods. However, from the modern period, heaps of ore processing wastes also exist, which generate AMD propagating for several kilometres downstream. At the same time, all these features bear critical raw materials. Therefore, regarding the environmental recovery model, a geoethical dilemma poses: should we extract the critical raw materials from all wastes and contribute to a circular economy model, or preserve these historical records in controlled environmental conditions?</p><p>With this example, the authors wish to explore how to embed geoethical thinking and values into the MCDA for post-mining land use, using the need to control and remediate the environmental issues of an abandoned mine.</p>