"1995: Thus the percentage recovery of metal from the ore was much higher than in the primitive process where the semi-vitrified gangue and half-smelted ore are typically rich in prills of copper and copper minerals. &mdash"
"1995: Thus the percentage recovery of metal from the ore was much higher than in the primitive process where the semi-vitrified gangue and half-smelted ore are typically rich in prills of copper and copper minerals. &mdash"