 He testified before the Industrial Commission as part of their investigation into mining on 14 July 1899.Coates was elected Lieutenant Governor of Colorado on a fusion ticket, having received the nominations of the Democratic, Populist and Silver Republican parties.In 1901, Lieutenant Governor Coates volunteered, and was dispatched by Colorado Governor James Orman, to be part of a commission sent to Telluride to investigate an uprising of miners from the Western Federation of Miners during a strike.