This map is based on 1:5000-scale geological mapping on a detailed topographic base, which included checking previous maps available in the archives of United Keno Hill Mines. In covered areas, the geology is derived from an analysis of about 9000 historic overburden boreholes, totaling approximately 250000 m, and 793 historic surface and near-surface boreholes, totaling 46748 m, on 1:1000-scale maps. The results of Alexco Resource Corp. surface diamond drilling of 197565 m in 759 holes, between 2006 and the end of 2019, are also incorporated in these maps and sections. On Galena Hill, a helicopter magnetic and resistivity survey on a 50 m line spacing allowed the extension of geologic structures into outcrop-free areas that have not been drilled.
