The main Carajás iron ore deposits are associated with flat-topped elevated plateaus, in general, elevated areas, between 650-800 meters, defined along two main morphological alignments
corresponding to Serra Norte and Serra Sul. These alignments materialize the limbs of the Carajás Syncline.

The Serra Sul Complex corresponds to the normal limb domain of the Carajás Syncline, characterized by a lower degree of deformation when compared to the inverse limb, which is reflected in the greater continuity of the iron formations.

The S11 deposit corresponds to the largest plateau and the main mineralized body of Serra Sul. This plateau extends for 28 km in the NW-SE direction. Its shape is segmented, with directions that vary sharply between N-S and E-W, configuring a kink-type pattern. The deposit includes A, B, C, and D bodies, the latter is the one of the highest economic interests. The plateau is predominantly composed of rocks from the Carajás and Igarapé Cigarra formations, which contact the Parauapebas Formation to the south, and Águas Claras Formation to the north. The layers present variable dips and azimuths shifting between the north and east directions, in general configuring a normal stratigraphic stacking.

At the eastern portion of the S11 plateau, which comprises the active part of the S11D mine, the geological information was obtained by mapping on a 1:2,000 scale, diamond drilling, trenches and channels.

The Carajás Formation corresponds to the thickest domain of the iron formations. It coincides with the highest elevations. The iron formations of the Carajás Formation domain occur as a tabular layer with medium to low dip angle to the north in the EW oriented bodies, such as S11D, and medium to high dip angle to the east and northeast in the NS oriented bodies, such as SSC. Its actual thickness has not been determined; however, it can exceed 450 m depth in section and varies between 200 m and 1,200 m in plan.

The S11 iron formation layout expresses strong structural control. Faults and folds conditions the thickness and continuity of the iron formations. The structures are correlated to the Transamazonian and Braziliano tectonics events, such as: Nucleation of the Carajás Syncline, folding with subhorizontal axes of NW-SE direction, verging towards SW, development of faults that imprint at SS11 plateau segmentation in kink style, formation of discontinuities filled by mafic dikes with NW-SE direction and implementation of normal faults that originate a horsts and grabens system, responsible for localized lifting of jaspillite bodies.

The friable hematite is the most representative lithology of the mineralization, it occurs from near the surface to depths greater than 450 m and presents average Fe grades around 68.8%, with relatively low levels of phosphorus, silica, alumina, and loss on ignition.

The cangas occur with wide expression on the surface of SS11 Plateau and represent the product of weathering on the different rocks in the region. Thus, they are differentiated according to the substrate and divided in chemical canga, which covers mafic rocks, enclosing or intrusive in the iron formation, and structured canga, developed directly over the iron formations and capable of economic use. It is a very hydrated lithotype with mineralogy with average Fe content of 64.2%, which contains alumina and phosphorus as main contaminants, in addition to high values of loss on ignition.

The Serra Sul Mining Complex is located in the north of Brazil. The property consists of orebody S11, subdivided on A, B, C, and D. Current production activities are in the S11D mine and the mineral reserves and mineral resources are defined only for the orebodies C and D.

Serra Sul has been operating since 2016, with production rates of approximately 80 Mtpa in the recent years. It is mined by open pit with berms and benches and uses large truck, shovel equipment and also In Pit Crusher Conveyor (IPCC) mining method.

The mine design includes benches 15m high, berms 15m wide, bench face angles from 50 to 85 degrees, according to the lithology in the mine. Ramp access is 40m width with 10% gradient.

The mining method at Serra Sul is open pit. Materials that require drilling and blasting and whose geometry does not favor to IPCC, are mined by normal truck and shovel, otherwise IPCC mining method is applied.

The movement of material is done by electric cable and/or hydraulic excavators into mobile crushers. The mobile crushing plants are equipped with a “sizer” (friable materials) or jaws crushers (compact material). Once the particle is reduced to the appropriate size for the conveyor belt, both the ore and the waste are sent to a transfer house where the conveyors are provided with a mobile head and adjust to transfer the ore onto a belt that takes it to a stockpile and the waste to another belt that sends to spreaders, which build the waste dumps.

Serra Sul processing plant annual capacity is 90 million tons of iron ore, with 3 lines of 30 million tons per year each.

The Truckless System delivers ore to a homogenization stockpile. After the pile, the material is directed to the primary screening where the oversize (+90 mm) is directed to the secondary crushing and the undersize together with the secondary crushing product is sent to the tertiary screening. The tertiary screening oversize (+19 mm) is directed to tertiary crushing where the product of this crushing returns as circulating load and the undersize of the screening constitutes the final product.

The ore is processed in the primary screening, consisting of 6 vibrating screens. The oversize of the primary screen (+90 mm) is directed to the secondary crusher, consisting of 6 cone crushers. The tertiary screen underflow constitutes the fine product.