Pyrite is a significant gangue sulphide mineral in the Ok Tedi
copper ore. Its presence in the flotation concentrate is not entirely
desirable since it lowers the grade of the final copper concentrate.
Lime depression of the pyrite has been practiced with some
success. However, it has been observed that at the pH for pyrite
depression a significant amount of the pyrite particles still float.
To obtain further insight into the problem this work has been
conducted to determine the composition, natural floatability and
xanthate flotation behaviour of the various types of pyrite in the
ore. The flotation results show that while some types of pyrite
float well at high pH values, others are readily depressed. The
implications of these results for Ok Tedi flotation plant have been
Considered.