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Less than half of the original two million km2 of the Brazilian Savanna natural vegetation, called the Cerrado Biome, remains standing. Given its climate and socio-biodiversity importance, more effective public policies are needed to protect the remaining natural areas. In this paper, we present the methodology and results of the DETER Cerrado, an early warning deforestation system within the Cerrado region. The findings support that DETER is effective in detecting a wider range of deforestation patch sizes, from the larger patches, heavily associated with agricultural expansion, to the smaller areas (>1 ha <10 ha). Nevertheless, 80% of the deforestation is concentrated in the 10-km radius zone from the DETER Alerts. This area was later detected by the Cerrado Deforestation Monitoring Project (PRODES), the system that accounts for the annual deforestation rate assessment, which highlights the capability of the DETER system to provide support to the surveillance of deforestation in the Cerrado. [ABSTRACT FROM AUTHOR]

The present work sought to investigate the applicability of the microCT scanning beyond petrophysics in oil and gas industry. We analysed external features (morphology) with all their nuances, and internal features such as mineral inclusions and vugs, in micrometric alluvial gold grains from one of the largest rivers in Southeastern Brazil. Owing to the complicated X-ray interactions with any metallic material, mainly gold, several imaging protocols were used until obtaining the most appropriate one. The results corroborate that microCT scanning can be a useful tool in provenance studies of detrital gold grains, even in an adverse analytical context and with small gold grain populations. [ABSTRACT FROM AUTHOR]

The historical Encardideira gold mine, currently known as Chico Rei, represents a rare case of gold mine owned by a freed slave in Brazil's colonial times. The term 'encardideira' alludes to the property of ingraining dirt on the surface of something. Here, we provide chemical and mineralogical evidence that the Encardideira mine likely had its name from the begriming character of its ore shoots. Gold-mineralised samples are enriched in graphite C, identified as tourmaline-enclosed euhedral graphite, and Mn-oxide minerals, mostly pyrolusite and cryptomelane-like material. Measurements for Au by atomic absorption spectrometry returned Au values above 1 ppm only after cupellation, suggesting the existence of graphite-bound gold in pervasively oxidised rocks. It is hypothesised that graphite-rich ore shoots, with superposition of Mn-oxide minerals, could account for enough gold and softness for manual removal by enslaved miners and their characteristic begriming. [ABSTRACT FROM AUTHOR]

The Palmeirópolis Zn-Pb-Cu volcanogenic massive sulfide deposit consists of four areas, presenting distinct features regarding host rocks, the geometry of ore bodies, hydrothermal alteration, deformation intensity, and metal proportions. The seven modeled Zn-Pb-Cu ore bodies occur mainly along with the contact between the Mesoproterozoic acid and basic metavolcanics within amphibolite facies. Some characteristics such as the relation of higher Zn-Pb and Cu grades to a higher proportion of acid and basic metavolcanic host rocks respectively, the same metamorphic grade and the gradational contact between volcanic host rocks, and distribution of alteration halo suggest that the original stratigraphy is still preserved. A smooth folding superposing the initial tight folds that define the ore bodies indicates at least two deformation events after the Zn-Pb-Cu mineralisation in the Palmeirópolis deposit. Finally, the geometry of the 3D ore bodies in Palmeirópolis are discussed against other VMS deposits around the world with 3D data available in terms of age, metamorphic, and deformation grades. [ABSTRACT FROM AUTHOR]

Recovering rare earth elements (REE) as by-products of existing mineral operations is a low-investment option to increase supply in short terms. REE-minerals were reported for the São João del Rei Pegmatitic Province (southern Minas Gerais State, Brazil) since the late 1940s, but data is scarce and dubious. The largest pegmatites project in the Province – Volta Grande mine – has been mined since 1945, producing concentrates of cassiterite, columbite-subgroup minerals, and microlite, and since 2018 spodumene is also recovered. Here we prepare a stream-specific mineralogical characterisation of the beneficiation plants to identify REE-minerals for potential REE recovery. The results analyse the feasibility of reprocessing some streams to generate a high-apatite product adequate for phosphoric acid production with REE recovery as by-products. The further REE speciation also revealed the preferential distribution of heavy-REE into columbite-subgroup minerals and light-REE into microlite, which may represent promising targets for the production of concentrates with high-purity. [ABSTRACT FROM AUTHOR]