This dataset is a compilation of samples collected from draining mine adits, including water and mineral precipitates, from several mines in California and Colorado. The Golinsky, Copper Bluff, and Afterthought Mines (located in northern California) and the Gold King mine (located in southern Colorado) have historically operated to recover metals including copper, lead, zinc, gold, silver and other resources (Albers and Robertson, 1961; USGS, 2005; USEPA, 2015). Data reported include field parameters, water chemistry, solid phase mineralogy and solid phase chemistry. Water samples collected from the four mine sites in 2019 were analyzed for unfiltered and filtered (0.1-0.45 micrometer) major and trace elements and iron oxidation state. At the Gold King Mine, water samples were collected at a draining adit and along a pipeline conveying water to a treatment plant. A small number of additional samples were collected from mine features near the Gold King Mine, including the Red and Bonita and Mogul Mines, as well as the American Tunnel. When available, solid samples were concurrently collected with the water samples and analyzed for bulk mineralogy and chemical composition. References: Albers, J.P., and Robertson, J.F., 1961, Geology and Ore Deposits of East Shasta Copper-Zinc District Shasta County, California: U.S. Geological Survey Professional Paper 338. [Also available at https://doi.org/10.3133/pp338.] U.S. Environmental Protection Agency, 2015, Gold King Mine - Watershed Fact Sheet: U.S. Environmental Protection Agency Fact Sheet 2015-08, accessed December 14, 2022, at https://www.epa.gov/sites/default/files/2015-08/documents/goldkingminewatershedfactsheetbackground.pdf. U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.