Photograph of a smelter at a mammoth copper mine in Shasta County, California, ca.1900. Lumber and other types of raw material lay scattered across the mining area. Many of the people can be seen working around a skeletal structure that appears to be still under construction. A little further up the mountain is the smelter(?). It stands about 2 stories tall. A ditch dug from half way up the mountain runs all the way down into the thick forest (foreground). At left, there's a train car with the name "Oregon Short Line, 5126" stenciled on it.; "The remaining copper extract is about 30% pure, and needs further refining. This is done through a process called smelting. To smelt an ore, it is heated to very high temperatures, causing the non-copper elements to react with the oxygen in the air, which is expelled as a gas. What is left is mostly copper (greater than 92% pure) which is usually rolled out onto sheets." -- unknown author.