Major Mines Projects | Morro da Mina Mine
Igneous metamorphism is now thought to have developed patches of the manganoan olivine tephroite (Mn2Si04) and other silicates, mainly at the expense of manganese carbonates. The ore at Morro da Mina consists of a mantle of manganese oxides, products of the removal of silica and carbonate from the protores by weathering.