Caracterização do depósito mineral de ferro localizado na terminação leste da falha Carajás, município de Curionópolis – Pa

Abstract

The Carajás province is located in the southeastern portion of the state of Pará and represents the oldest part of the Amazonian Craton, it is worldwide known for its large concentration of world class deposits. The survey area is covered by the research grant of the company LBR Mineração LTDA and is inserted in the mentioned context, located nearly 30 km in the southeast of the city of Curionópolis - Pará. In the area comes up a mineralized body of iron belonging to the Carajás formation, placed on basaltic rocks of the Parauapebas formation. The deposit has NE-SW direction with dive and high angles for NW, being foliated and intensely fractured with development of "ore gaps". In these structures and mineralogical zoning as it approaches to the center composed by hematite, magnetite and maghemite characterizing the process of martitization, or of the extremities where the dissipation of Maghmita is observed and increasing of the hematite contents manifesting a greater oxidation related to the center, along with greater cavity development and occurrence of silica and aluminum silicates. However, in the opposite direction from the edge to the center of the ore body the occurrence of cavities is more developed (forming a lens> 1mm) and the amount of it increases considerably. Occasionally the hematite crystals preserve the octahedral inurement, thereby, restricting the presence of magnetite only as the relic core of these replaced crystals. The chemical analysis data showed a directly proportional relation between the increase of Maghemite and Fe content (up to 70%) and low levels of silica and phosphorus contaminants.