National Geographic : 1942 Apr
©Spence from Ewing Galloway North America's Largest Open-pit Copper Mine, in Bingham Canyon, Utah, Where a WholeMountain IsBeing Eaten Away To some it suggests the rice terraces of the Philippines. Actually it is a triumph of mass production, for large-scale methods have produced fabulous quantities of copper-plus gold, silver, and molybdenum as by-products-from 1 percent ore, so lean that some considered it worthless (page 489). Along theterraces crawl ore trains, often as many as 23. In the foreground is the town of Copperfield, squeezed between mountain walls.