In its time, the Holden Mine was the largest copper mine in the U.S., extracting gold, zinc, and other minerals. The mine’s been shuttered for the past 50 though, and if something’s not done, toxic materials will seep into our groundwater for at least the next couple hundreds. Our own Clint Strand (I) traveled uplake almost to the headwaters of Lake Chelan to see the damage firsthand, and what officials plan to do to fix it.