The MetalMapper is an electromagnetic metal detector that is being commercialized by Geometrics, Inc with support from the Environmental Security Technology Certification Program (ESTCP). Together with several other systems, the MetalMapper participated in an ESTCP-sponsored classification study at the former Camp San Luis Obispo (SLO) located a few miles northwest of San Luis Obispo, CA. Operating independently, the MetalMapper conducted two surveys: a dynamic mapping survey for target detection; a precision (Cued ID) static measurement over detected targets for use in discrimination. The SLO study involved a number of different organizations deploying both commercially available EM and magnetic sensors and advanced EM systems such as the MetalMapper. Following the completion of the field work by these organizations, nearly 2000 targets identified from the detection surveys were then dug. Using a common set of targets, demonstrators prepared a dig list prioritized according to the probability that a particular target was a target of interest (TOI). The dig lists were scored by the Institute for Defense Analyses (IDA). The primary objective of this paper is to describe MetalMapper system, the data processing, and the methodology employed for assembling the prioritized dig list. We also present the scoring results for the MetalMapper as provided to us by the IDA.