Jun 20, 2013· ITP Mining: Energy and Environmental Profile of the . – EERE. Specifically, magnetite and hematite are the main ironbearing ores in the Lake . Concentrations of as little as 30 percent may be of commercial interest, . classified as either high or lowintensity (requiring as little as 1,000 gauss or as much as. 20,000).Particle size and the solids content of the ore determine which ...