At the Ore Treatment Facility (OTF), the raw material extracted from the soil is treated to obtain final products of Mineração Usiminas. In this phase, the ore undergoes a process of fragmentation, separation, classification and concentration; this always is done for the purpose of enriching and improving its value.
This process is divided into two stages:
In the first, primary, secondary and tertiary crushing occurs to gradually reduce the size of the ore and screening, where separation by size and cleaning by pressurized water occurs to generate the lump ore.
The second stage of the processing is concentration. By means of use of specific equipment such as jigs, spirals, magnetic separators and water screen, the sinter feed and pellet feed originate.
Mineração Usiminas is among the first companies in the world to use a concentrator with three rotors. The high intensity magnetic equipment has the function of attracting the ore with a magnet. The magnetic particles are attracted and stick to magnetization plaques (the concentrate will be used further on), the non-magnetic particles are discarded by hydraulic drag and by gravity (tailings).