Hecla Mining Company is a gold, silver, and other precious metals mining company based in Coeur d'Alene, Idaho. Founded in 1891, it is the second-largest mining company that produces silver in the country. This area is known as the Silver Valley. In 1983, this entire area was designated as a Superfund site by the Environmental Protection Agency, because of land, water, and air contamination resulting from a century of mostly unregulated silver and gold mining. Wikipedia