An advanced prospecting method for assessing the quantity of underground metal cables urban mines

Abstract

One way to stimulate a more circular economy, is to explore opportunities for urban mining. This thesis explores a new method to assess the quantity of underground electricity cables which could one day become available for urban mining. This research answers the question: ”To what extent can topological networks be used to localize and quantify underground metal cables in order to assess the quantity of an underground urban mine?” Three case study areas in Amsterdam have been selected to exemplify the method. The Dutch National Road Network has been used as a topological skeleton to approximate the electrical network.

Three different methods were used to connect buildings and transformers to this network. The ’Connect to Closest Point’ method, connects every point to the closest point on the street network. The ’Connect to Closest Junction Vertex’ method connects every point to the closest junction vertex of the street network, which is divided into segments with maximum length of 75 meters. The ’Iteratively Connect to the Closest Junction Vertex’ method iteratively connects every point to the closest junction vertex, within a threshold, until all nodes are connected to the street network.

By evaluating the edge betweenness [Girvan and Newman, 2002] for every edge in the topological networks, cable current and thickness could be determined and the urban mine was quantified in terms of electrical cables. The ’Connect to Closest Junction Vertex’ method showed to be most accurate, with up to 88% accuracy in Geuzenveld. Although this method is suitable for finding a minimum quantity of an underground urban mine, locational accuracy is too low to pinpoint the exact location of underground cables.