The Kerr-Sulphurets-Mitchell copper-gold-silver mine proposed near the headwaters of the Unuk River (which flows into Misty Fiords National Monument in Alaska) is indeed massive. It’s open pits and rock storage facilities will cover approximately 30 square miles. It is expected to process a minimum of 120,000 tonnes of ore per day, 120 million tonnes per year, over a life of 52 years.
Victoria McDonald has written an excellent opinion piece in Stories in the News on this mine and it’s ramifications to water quality and fish habitat.
For more information about the Kerr-Sulphurets-Mitchell mine, see this briefing document.