UG-2 DOMINANCE

UG-2 dominance is a function of the dual mining of chromite and PGMs from the same reef, but UG-2 ores are low in sulfide and base metals, a key to the successful melting processes developed for PGMs in Southern Africa. 

UG-2 concentrate is characterized by high concentrations of Cr₂O₃ (thus more refractory than Merensky concentrate) and significantly lower sulfur and base metal content. The blending practices and limiting Cr-content has become part and parcel of the industry, resulting in strict chrome penalties being applied to concentrates beings processed in the traditional furnaces. 

Merensky and UG-2 Reef dominated the production of PGM concentrate for many decades with Platreef (chemically and mineralogically closer to Merensky) emerging in the past decade due to depletion of economically viable Merensky arisings. 

With the depletion of Merensky, blending of Platreef concentrates has become a primary focus of many of the majors, while UG-2 remains dominant across the board, the Platreef is viewed as a key enabler to continue the traditional smelting route. 

A consequence for smaller producers is the loss of PGMs to the tailings due to the need to minimize chrome in the saleable product. 

While this constraint is part and parcel of the industry landscape, alternative solutions exist if the chrome constraint can be released.