High Quality Content by WIKIPEDIA articles! The San Juan Mountains are a rugged mountain range in the Rocky Mountains in southwestern Colorado. The area is highly mineralized (the Colorado Mineral Belt) and figured in the gold and silver mining industry of early Colorado. Major towns, all old mining camps, include Creede, Lake City, Silverton, Ouray, and Telluride. Large scale mining is now uneconomical in the region, although independent prospectors still work claims throughout the range. The last large scale holdouts were the Standard Metals operation near Silverton, which operated until late in the 20th century and the Idarado Mine on Red Mountain Pass that closed down in the 1970s. Another hold-out was the ill-fated Summitville mine on the eastern slope of the San Juans.