Coeur d'Alene Iron Works - Mining Jaw Crusher

"The result of blasting in ore production areas is chunks of rock that are frequently 4 inches or more across. To get the greatest metallurgical recovery, it is necessary to pulverize this rock into the smallest size possible.  This is normally accomplished in a multi-stepped process.

The first step is the jaw crusher, which utilizes a movable jaw being forced towards a fixed jaw with tremendous force.  The chunks are reduced to gravel-size chunks less than one inch in diameter.  From here, the gravel usually moves to a cone style crusher, which then breaks the chunks into an even smaller size.  Those smaller chunks then move to a ball mill, where a huge rotating drum charged with large steel balls pulverises the material into a talcum powder consistency."

--Plaque at the Silver History Site in Wallace Idaho, displayed near a prototype of this jaw crusher.