The Greens Creek deposit is a 24.2-million-ton polymetallic massive sulfide with a diverse base- and preciousmetal-rich mineralogy, which has been subjected to regional lower greenschist facies metamorphism. Roughly 30 percent of the ores retain primary mineralogy and mineral textures as well as gross original ore stratigraphy. Ore lithologies fall into two groups: massive sulfide ores (greater than 50 percent sulfides) and semimassive or disseminated sulfide gangue-rich “white” ores (less than 50 percent sulfides). There are two types of massive ore: massive pyritic and massive base-metalrich ore.

In 1996, a memorandum of understanding was signed by representatives of the U.S. Geological Survey and Kennecott Greens Creek Mining Company to initiate a cooperative applied research project focused on the Greens Creek massive sulfide deposit in southeastern Alaska. The goals of the project were consistent with the mandate of the U.S. Geological Survey Mineral Resources Program to maintain a leading role in national mineral deposits research and with the need of Kennecott Greens Creek Mining Company to further development of the Greens Creek deposit and similar deposits in Alaska and elsewhere.