Several non-ore material can enter to the extraction process and creates a negative effect on gold recovery. Some of them are ferrous wear debris, vegetation, metallic pieces from mining equipment, rubber and lubricants. The first group is derived from crushers and comminution equipment. Iron oxides are deposit on gold surfaces and affect the recovery a recovery process like flotation due to modify the polarity required to attach gold particles on bubbles. Cyanidation is affected by this situation.
Vegetation enters a plant feed when treating near surface ore or tailings dumps, material from underground operations. This material affects flotation and cyanidation. If this Material is in contact with alkaline solutions such as pH 9.0, will be liberated water soluble organic compounds. Some of these products produce frothing agents that creates overfrothing.