It is essential that ores from different sources for blending should have same mineralogical structure and closer grain size as well. Blending process is applied for concentrates or for bulk ores only and they are not mixed with each other. Arithmetic mean of elements is taken as final specification at the end of process.

Oxidised ores and sulphide ores are never mixed and are kept separately. High grade Ores/concentrates are stored separately and not subject to additional processing.

Low grade ores can be processed to obtain concentrate by downscaling, by separating from site minerals. For example: Grain size of 10-30 cm, could be downscaled to 125-150 microns for Pb-Zn (Lead-Zinc) and to 32 micron for Cu (Copper).

Cu (Copper) , Ag (Silver) and Au (Gold) in the concentrate are separated. All elements should be identified properly since As (Arsenic) , Ag, (Silver) , Au (Gold) , Cd (Cadmium) are important for receivers and Pb (Lead) is not wanted in Cu (Copper) and subject to penalty over certain limit. Pb (Lead) in Zn (Zinc) and Zn (Zinc) in Pb (Lead) may vary depending on terms and conditions declared by smelters and therefore separated and stored accordingly.

Moisture should be determined accurately as dry weight is taken into account in contract.