mining technology: Iron Ore Processing for the Blast Furnace
The magnetic iron ore is then laundered in two slurry surge tanks while the non-magnetics (silica/sand) go to the tailings disposal area. Most of the material continues to be finely ground in one of five secondary ball mills, which are powered by electric motors ranging from 2,500 hp to 4,000 hp and are charged with 1-1/2" chrome grinding balls.