Pebble Mine is the common name of a proposed copper-gold-molybdenum mining project in the Bristol Bay region of Southwest Alaska, near Lake Iliamna and Lake Clark. Discovered in 1987, optioned by Northern Dynasty Minerals in 2001, explored in 2002, drilled from 2002-2013 with discovery in 2005. Preparing for the permitting process began and administrative review lasted over 13 years. As of November 2020 the mine developer, Northern Dynasty Minerals, still sought federal permits from the United States Coast Guard and the Bureau of Safety and Environmental Enforcement. State permitting would then follow, which the developer expected to take up to three years. In November 2020, the U.S. Army Corps of Engineers (USACE) denied a permit for the proposed mine discharge plan. On September 9, 2021, it was reported that the United States Environmental Protection Agency had "asked a federal court to allow for Clean Water Act protections for parts of the bay." On January 31, 2023, the EPA effectively vetoed the project, using a rarely invoked power to restrict development to protect watersheds. Background Geography The Pebble prospect is in a remote, wild, and generally uninhabited part of the Bristol Bay watershed in Southwest Alaska. The nearest communities, about distant, are the villages of Nondalton, Newhalen, and Iliamna. The site is southwest of Anchorage, Alaska. Pebble is approximately north of, and upstream of, Lake Iliamna, and near Lake Clark. The deposit area is characterized by relatively flat land dotted by glacial ponds, interspersed with isolated mountains or ranges of hills rising one or two thousand feet above the flats. Pebble is under a broad flat valley at about above sea level dividing the drainages of Upper Talarik Creek and the Koktuli River. Upper Talarik Creek flows into Lake Iliamna, which flows through the Kvichak River into Bristol Bay. Waters in the Koktuli River drain into the Mulchatna River, a tributary of the Nushagak River which empties into Bristol Bay at Dillingham. Water from Lake Clark, approximately east of Pebble, flows down the Newhalen River to Lake Iliamna. Geology Regional The Kahiltna terrain is interpreted to represent a sediment trough formed on the landward (Alaska) side of the Wrangellia volcanic arc terrane, prior to collision of Wrangellia with Alaska. The Wrangellia and Kahiltna terrains docked to Alaska in the Cretaceous Period. This part of the Kahiltna terrane is dominated by Late Triassic basalt, andesite and sedimentary rocks overlain by Jurassic-Cretaceous andesitic