Sossego is owned and operated by Salobo Metais S.A., a wholly-owned subsidiary of Vale Base Metals Ltd., the holding entity for Vale’s Energy Transition Metals business.
On April 30, 2024, Vale S.A. announced the completion of the sale of Vale Base Metals Ltd. (“VBM”) to Manara Minerals, under which Manara Minerals will acquire a 10% stake in VBM.
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Summary:
The Sossego iron oxide–copper–gold deposit in the Carajás Mineral Province of Brazil.
The Sossego deposit is associated with a 10 km regional structural shear zone striking northeast to southeast and dipping steeply to the south. A series of copper gold deposits are associated with this structure including Sequerinho, Sossego, Jatobá, Serra Dourada and Cristalino deposits.
The Sossego deposit has been divided into 4 main zones, from west to east areas: Pista, Sequerinho, Baiano and Sossego Hill of which, the Sequeirinho deposit is the most important in terms of size.
Sequerinho consists of a single and continuous zone of mineralization with a strike length of approximately 2000 m with weaker mineralization extending another 1000 m to the west. This deposit is situated about 700 m west-southwest of Sossego Hill and out crops as a prominent hill with approximately 40 m of relief over the general landscape.
The sulphide deposit has a sigmoidal shape, trending west-northwest on the extremities of the deposit, and northeast in the central portion. The western extremity is referred to as the Pista sector and the eastern portion is called the Baiano sector. Mineralization generally occurs as a series of sub-parallel bodies with aggregate thicknesses ranging from 25 m to nearly 300 m. Dips are generally steeper on the extremities, ranging from 70°S to sub-vertical. In the central portion of the deposit dips are locally as shallow as 45° to the southeast. The deposit is cut by a north-northwest trending diabase dike at the eastern transition of the Sequeirinho and Baiano portions of the deposit.
Mineralization at Sequeirinho is structurally controlled and cuts the felsic volcanic, granite and gabbro host rock units. The majority of the hanging wall is composed of a granitic/tonalitic rock with dikes or remnants of mafic rocks. The footwall is defined by a sharp contact that separates the mineralized zone from the altered biotite schists of the Carajás volcanic sequence (locally felsic volcanics). The footwall boundary can be roughly followed by a topographic break to the north of Sequeirinho and is characterized by an abrupt drop in the chalcopyrite-actinolite-magnetite content and an increase in the scapolite-biotite content.
The high-grade sulphide mineralization occurs in breccias that are usually richer in copper and gold near the footwall and hanging wall contacts of the ore body as well as in crosscutting zones. The breccias have a chalcopyrite matrix and clasts of magnetite, amphibole and other lithic fragments. The breccias zones are surrounded by a lower grade envelope consisting of irregularly distributed disseminated chalcopyrite mineralization. Copper and gold are well correlated. Near surface oxidation has produced pseudo-malachite and malachite.
The Sossego Hill deposit is part of a broad circular feature, about 100 m in diameter and standing about 10 m in elevation. The core of the circular structure is a medium to coarse-grained pinkish to dark gray granite cut locally by gabbro dikes. At the contact with the Carajás felsic volcanic rocks, the granite has a fine grained texture (granophyric texture) forming a granophyre with up to 200 m in width characterized by quartz-potash feldspar intergrown with blue quartz eyes. This granophyre usually has a transitional contact with the granite, indicating that the fine-grained texture is related to a border facies. This entire set is cross cut by two main chalcopyrite-rich breccia pipes, namely Sossego Hill and Curral.
Mineralization occurs in three zones; the roughly circular, 200 m diameter Sossego breccia in the northern part of the mineralized area; the elongated 80 m by 400 m Curral breccia to the south, and the Vein Zone, an irregularly veined zone between the Curral and Sossego breccias. The breccias at Sossego Hill and Curral are heterolithic, matrix supported with fragments of granitoids, mineralized fragments, granophyre, and gabbro in a hydrothermally altered matrix composed of potassium feldspar, calcite and varying proportions of chlorite, magnetite, apatite and chalcopyrite. The heterolithic breccias also occur within irregular hydraulic fractures of variable width (from a few centimetres to nearly 20 m) that often branch and terminate as nearly pure chalcopyrite veins. Stockwork and disseminated mineralization is also present. The contacts between high-grade mineralization and barren material are abrupt. Chalcopyrite is the main copper bearing mineral.