Corumba ore reserves are comprised of hematite ore type, which generates operations lump ore predominantly.

The manganese and iron deposits of the Morro do Uruclun are located about 25 kilometers south of the city of Corumba, Mato Grosso, Brazil.

The deposits of both manganese and iron occur in the Jacadigo series, of unknown but probably late pre-Cambrian or early Paleozoic age. This has been subdivided into the Urucum, the Corrego das Pedras, and the Band' Alta formations. The Urucum formation, between 400 and 500-meters thick, consists of continental deposits of arkose and conglomerate. It grades upward into the Corrego das Pedras formation, about 95 meters thick, in which ferruginous arkose at the base grades upward into ferruginous sandstone and ferruginous jasper. Above the Corrego daa Pedras formation is the Band' Alta formation, at least 300 meters in thickness, which contains the deposits of manganese and iron. At the base of the Band' Alta is a widespread bed of the manganese oxide cryptomelane. This is overlain by banded siliceous hematite, which makes up the greater part of the formation but is interbedded, about 40 meters or more above the base, with other lenticular beds or cryptomelnns, and, higher in the section, with lenticular beds of clastic rocks, including siltstone, sandstone, and, rarely, conglomerate. The formation is cut off at the top by an erosion surface.

The Corumba formation consists of calcareous shales and argillites, sandy shales, black, well-bedded limestone, gray limestone and dolomite, andwhlte dolomite. It extends at least 200 kilometers westward from Corumba into Bolivia, 100 kilometers to the south, more than 100 kilometers to the north, and an unknown distance to the east.

In many localities the Corumba formation has been marmorized. Although this recrystallization has been attributed to metamorphic effects of the intrusive granite which crops out near Fazenda do Urucum, it is more probably the result of dynamic stresses induced during the complex deformation of the area. There is no known evidence to prove or even strongly indicate that the granite is intrusive into the Corumba formation.

Open-pit mining operations.

The beneficiation process for the run-of-mine consists of standard crushing and classification steps, producing lump ore and sinter feed.