.
Location: 27 km S from Corumbá, Brazil
Rua Cabral 1555, CentroCorumbáBrazil79332-030
Stay on top of the latest gold discoveries. Examine the latest updates on drilling outcomes spanning various commodities.
Mining scale, mining and mill throughput capaciites.Full profiles of select mines and projects.
Shaft depth, mining scale, backfill type and mill throughput data.Full profiles of select mines and projects.
Equipment type, model, size and quantity.Full profiles of select mines and projects.
Camp size, mine location and contacts.Full profiles of select mines and projects.
The Urucum deposits are associated with banded iron formations (BIF), locally known as jaspelites. The iron and manganese deposits are found in the plateaus which rise from the plains of the Paraguay River and near Mutum Mountain.The sediments of the Urucúm Basin constitute an epicontinental marine sequence beginning with the basal Jacadigo Group that comprises clastic sediments with carbonatic matrix, overlain by iron-rich arkoses and Jaspilites with manganese layers (Band'Alta Formation), followed by the Corumba Group with limestones, dolomites slates and siltites (Cerradinho Formation) overlain by dark dolomites and limestone breccia of the Araras Formation. This sequence developed in a slow sinking basin with upward gradation from clastic to chemical sedimentation without volcanic contribution. Deposition of widespread iron and manganese rich sediments is due to sharp variation in the Eh conditions most probably under the influence of marine currents in a restricted basin partially protected from atmosphere by large ice caps.The jaspilites of the Band'Alta Formation present a primary banding defined by planar layers and lenses of quartz and hematite, with variable thickness, from mm to cm. (Fig. 4d). Quartz is usually cryptocrystalline (chert) and hematite appears, similar to the Carajás jaspilites, as microcrystalline aggregates or as very fine platy crystals. Recrystallization of both hematite and quartz results in xenoblastic aggregates that occur discontinuously. Near to the contact with manganese layers hematite may also appear intergrown with cryptomelane (Schneider 1984). Martite is also present in form of hypidiomorphic to idiomorphic crystals as individuals and aggregates. Fine clastic components are common at the base of the sequence but are also present as layers and lenses in the upper levels. Erratic blocks of glacial origin are quite frequent. The most puzzling feature is the presence of small hematitechert ellipsoidal concretions with variable diameter (few mm to several cm), displaying a concentric structure similar to oolites. They are always aligned on the banding and own their shape to differential compaction. Thicker levels of primary high-grade ores occur in the whole sequence. In these layers, banding is less conspicuous, defined by slight variation in the proportions of quartz (chert) and hematite. Superficial leaching of the quartz leads to the development of a very high grade ore especially suitable to direct reduction plants.
- subscription is required.
