Two Bucyrus dredges, the Colorado I (right) and Colorado II (left), in the Swan River Valley at Valdora, north of Breckenridge, Colorado. Circa April 1908. The Colorado I dredged down the Swan River and turned up the Blue River, where it broke down in 1910 and sat idle until 1914. It operated on and off on the Blue River from 1914-1942. The Colorado II went up the Swan River where it operated continuously until 1919. In 1914, both dredges were purchased by the Tonopah Placers Company and renamed Tonopah No. 1 and Tonopah No. 2.

Men on the bank of the Swan River watch the Colorado Gold Dredging Company's Bucyrus dredge (called Colorado II) bring up gold bearing gravels from bedrock on June 13, 1913. The Colorado II was the seventh dredge built in the Breckenridge, Colorado area.