A wide variety of valuable mineral resources exist within the Tongass, including gold, silver, platinum and other precious metals, as well as copper, zinc, and lead deposits. Since the late 1800s, industrial mining has played a considerable role in the region, with exploration and production continuing today. The 1872 Mining Law assures access and development to all public lands open to mineral entry, regardless of the impacts to other forest uses. Historic mining claims on lands that were later designated as Wilderness or National Monuments may still be developed even though future mining claims are prohibited. One of America’s largest operating silver mines is located on Admiralty Island National Monument. According to a 1998 Toxic Release Inventory by Environmental Protection Agency, Greens Creek Mine was the second largest producer of toxic waste in Alaska.