Figure 1:
Tectonic Provinces of the Guiana Shield, as presented by the Tectonic Map of South America (Cordani et al. 2016Cordani U.G., Ramos V., Fraga L.M., Cegarra M., Delgado I., Souza K.G., Gomes F.E.M., Schobbenhaus C. 2016. Tectonic Map of South America, second edition, 1:5,000,000. Commission for the Geologic Map of the World.), and their main mineral deposits.
Figure 2:
Depository areas of manganese and iron-rich sediments of the Vila Nova Group greenstones in the States of Pará and Amapá, outlined over the Geologic Map of Brazil at 1:2,500,000 (Schobbenhaus et al. 2001Schobbenhaus C., Campos D.A., Derze G.R., Asmus H.E. 2001; Mapa Geológico do Brasil e da Área Oceânica Adjacente incluindo Depósitos Minerais; 1:2,500,000; DGM-DNPM).
Figure 3:
Geology of east of Serra do Navio, with mines of gold, iron and manganese. Presented over the radar image of Projeto Radam (Lima et al. 1976Lima M, Montalvão R., Issler R., Oliveira A, Basei M., Araujo J., Galeão da Silva G. 1976. Folha NA/NB.22, Macapá. Projeto Radam; MME-DNPM Levantamento de Recursos Naturais, V-6, Geologia, ).
Figure 4:
Geologic map of Serra do Navio with deposits and occurrences of manganese of the Serra do Navio and Serra da Canga Formations.
Figure 5:
Serra do Navio Formation cyclothem in longitudinal and transversal sections of the C2 deposit (Scarpelli 1972Scarpelli W. 1973. The Serra do Navio Manganese Deposit (Brazil). In: Unesco - Proceedings of the Kiev Symposium on the Genesis of Precambrian Iron and Manganese Deposits, p. 217-228.).
Figure 6:
(A) Andalusite (and) porphyroblast preserving lines of grains of graphite (gr), remnants of the first dynamothermal metamorphism. Sillimanite needles (sil), and biotite (bi) plates, formed during the second dynamothermal metamorphism, replace andalusite. (Mine C-2, hole 42, 41 m). (B)Twinned staurolite in quartzous graphitic schist; biotite, quartz; graphite and tourmaline (tour). (Xnicols, mine T4, hole 30, 84.5 m). (C) Garnet-biotite-quartz schist with andalusite porphyroblast rotated to 90º of foliation. Pressure-free areas at both sides of the porphyroblast are filled with quartz. Biotite and muscovite (ms), and feldspar (fd). (Xnicols, mine T-20 hole 15, 86 m). (D) Biotite-garnet-quartz schist with an almandine garnet (gn) broken in two fragments during the second dynamothermal metamorphism, with one of them pushed along a curved path, up and to the left in the figure. Clouds of sillimanite needles formed where the moving half garnet pressured and heated the rock along its path, while quartz filled the zone of low pressure behind it. (Mine C5, hole 2, 75 m).(Scarpelli 1969)
Figure 7:
Calcic-Magnesium Domain. Left: Impure and weakly foliated marble, with serpentine, brown grunerite, magnetite and pyrrhotite. Center: Carbonates, diopside, grunerite, with biotite in bands. Right: Impure marble with fine grained diopside
Figure 8:
Ferrous Domain. Bif 2, at left, with lighter bands of quartz, grunerite and diopside alternating with darker bands of magnetite, hornblende, and grunerite; yellowish bands are rich in pyrite. Bif. 4, at right, formed essentially by bands of hematite and quartz. Units of Bif 4 are more common in the area mined for iron.
Figure 9:
Geology of the area with the gold and iron mines of Beadell and Jindal. The larger gold deposits occurr in iron formation, controlled by shears and faults. At west of the major controlling shear, TapD gold deposit occurs in a wedge of the Calcic-Magnesian Domain. Mineral rights of the complete area belongs to Beadell, with Jindal owning rights to exploit iron south of the divide line. (Base geologic map from Horikava E.H. 2008Horikava E.H. 2008. Geoquímica de Solo e Geologia da Região do Depósito de Ouro do Amapari - AP. MS Dissertation, Universidade Federal de Minas Gerais, 2 vol.).
Figure 10:
Details of the 26 meters drill intersection of a mafic-ultramafic intrusion in the Serra da Canga Formation at Canga. (From Horikava & Ferreira Filho 2003Horikava E.H., & Ferreira Filho C.F. 2003. Corpos Máficos-Ultramáficos Acamadados da Região da Serra do Navio. In: VIII Simpósio de Geologia da Amazônia, Expanded Abstracts, Sociedade Brasileira de Geologia, CD-ROM.).
Figure 11:
Cross section of the T6 mine, showing effects of the shear zone on structures, depth of weathering and ore types. The oxide ores were mined out.
Figure 12:
Initial geologic profile of the Urucum orebody, as prepared by Minorco. Mineralization is preferentially hosted in the faulted iron formation. Values next to the trace of the holes indicates grades of gold (g/t Au) and meters of mineralization.
Figure 13:
North-south line of pits opened by Beadell, with Tap AB1 in the first plane, Tap AB2 and Tap C in sequence, with Urucum in the horizon, near to the high plateau of the Serra da Canga. Photo from Beadell open presentation of November of 2016.
Figure 14:
Longitudinal section of the 2.2 kilometers long Urucum pit, outlining exploited and unexploited portions of the main orebodies of the deposit, which plunge north, are crossed by one large pegmatite, and are open in depth. The pit surpasses 250 meters of maximum depth. At north, Beadell identified a reserve for underground mining totalling 3.0 million tons at 3.61 g/t Au. (Based on illustrations presented by Beadell Resource 2010-2017).
Figure 15:
Exposures of iron formation in the area of Jindal. Left, outcrop of the ore, represented by a massive and erosion resistant magnetite/martite-rich unit. Right, exposed on a road cut, the friable hematitic iron formation, a type that never outcrops and is the favorite for mining due to its high grade and low cost to mine and process.
Figure 16:
Above, fresh iron formation constituted by bands of magnetite, quartz and silicates. Below, weathered, with layers of martite and hematite replacing magnetite, and with limonite replacing silicates and most of the quartz. The texture of the bands varies from massive to friable. Open spaces indicate where minerals were completely leached out.
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