This Engineering Evaluation and Cost Analysis included a supplemental site investigation for four targeted areas of interest (AOI) to evaluate data gaps and volume estimates of contaminated materials at the Cordero Mine Site in northern Nevada. Work on this project was completed with Pinyon’s teaming partner, Jacobs Engineering. Site characterization indicated that elevated levels of arsenic and mercury exceed three times the soil background concentrations in the four areas of interest. In addition, soil concentrations of cadmium, chromium, and lead are also elevated. Furthermore, sediment and soil contamination was widespread throughout the mining project boundary, based on visual observations and samples collected outside the boundaries of the AOIs. A streamlined or screening level human health and ecological risk assessment indicated that mercury, arsenic, and lead exceeded the recreational exposure scenario screening levels, and that arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, and polychlorinated biphenyl (PCB) – Aroclor 1254 exceed the ecological screening levels for ecological exposure. However, the soil sample results from the synthetic precipitation leaching procedure for Resource Conservation and Recovery Act (RCRA) 8 metals were below U.S. Environmental Protection Agency water quality allowable limits. Utilizing the data collected by Pinyon, Jacobs Engineering prepared the alternatives analysis and cost estimates necessary to evaluate the options for non-time critical removal actions. Because of the extensive impacts and the relatively high cost of a site repository, our Team recommended a combination of engineering and administrative controls for potential future implementation at the site.