Studies of the geology, hydrothermal alteration, and mineralogy of the Handcart Gulch research watershed were conducted as part of a multidisciplinary approach to understand the hydrology and effects of geology in a typically mineralized alpine watershed (figs. 1 and 2). The study arose out of the donation of four abandoned, deep mineral exploration boreholes for research purposes by Mineral Systems Inc. to the U.S. Geological Survey (Caine and others, 2006; Verplanck and others, 2008).