Nova Lima Research Articles

Major recent failures in Brazilian mine waste containment facilities, current cases of maximum emergency level and imminent risk of rupture, and a brief sustainability analysis.

Wasteisthe materials left over after the processing of ores. Significant disasters involving waste disposal structures have occurred in Brazil in recent years and caused severe damage by contaminating soil, rivers and coastal areas, destroying native fauna and flora, interrupting the water supply and compromising its potability, putting the population's health, livelihoods and economy at risk, as well as causing 289 irreparable human deaths. Regulatory laws have become stricter, and since 2019, after the tailings dam tragedies occurred in 2015 and 2019 in Mariana and Brumadinho, in Minas Gerais, the operation of upstream-raised tailings dams has been prohibitedin Brazil. In 2022, a waste slide from a sterile pile at the Pau Branco Mine in Nova Lima promoted a dike overflow. There was the death of five people whose car was buried by a landslide on a hillside. New strategies and technologies, such as reprocessing and recycling, can be tested to ascertain whether they can help improve practices in tailings management. Indeed, mining companies' corporate responsibility and sustainability practices need to be evaluated toverify whether they better match expectations. On the other hand, more specific and detailed regulations and resolutions are required to ensure the safe monitoring and management of sterile waste piles. This paper presents a review of the facts, a discussion of the literature (mainly on recent tailings dam disasters), the current situation of mining-containingwaste structures in Brazil, a brief sustainability analysisand perspectives aimed at preventing/minimising catastrophes in the future.

Potential toxicity of iron ore tailings after the overflow of a mining dam in Nova Lima (Minas Gerais State, Brazil)

In January 2022, the Pau Branco Mine dam in Nova Lima (MG), under the responsibility of Vallourec, overflowed after intense rainfall and iron ore tailings impacted surrounding soils and aquatic ecosystems. These tailings can alter the natural composition of soils and rivers, poising risks on soil biota. This study consists of a preliminary evaluation of potential toxicity of terrigenous materials impacted by tailings from the Pau Branco Mine, based on acute bioassays with earthworms (Eisenia andrei) and germination tests with lettuce (Lactuca sativa). The physical and chemical characterization and determination of toxic metals in the samples supported the interpretation of the ecotoxicological data. The results indicated that the tailing deposition induced the increase in particle density, due to the increase in iron concentrations in the samples. As a consequence, the water holding capacity (WHC) of the materials and organic matter concentrations were dramatically reduced. Given that the mining tailings exhibit fine texture, their depositions on soils increased the percentage of fines particles (silt) in the samples. Metal determination revealed geochemical anomalies for nickel, copper and chromium, whose concentrations exceeded the threshold limits defined by Brazilian law for soil and aquatic sediment quality. The bioassays with earthworms showed no significant earthworm mortality, indicating low acute toxicity. However, earthworm biomass was significantly reduced, suggesting that they were submitted to some stress induced by the exposure to contaminants and/or by the reduction of the organic matter contents (food scarcity) and WHC (water scarcity). The bioassays with lettuce showed no significant effects on germination levels. However, the seedling biomass was significantly reduced due, possibly, to the reduction of WHC and especially due to the increase of fines particles in the samples, which tends to inhibit the establishment of the root systems.

“We are right in the middle of them”: mining and the production of disasters

This article draws on the history of Mingú, a neighborhood located at the center of the activities of a long-standing mining company in Nova Lima, in the state of Minas Gerais, Brazil, and discusses the interrelation of the production of disasters over time with the formation of a socio-spatial group. The narrative is informed by fragments of everyday life that seek to highlight the trends and patterns of broader processes, and which resonate beyond the particular context presented. Three phases in the history of Mingú are analyzed, revealing the continuity between extractivism and neoextractivism and the notion that disasters are not restricted to natural events, isolated in time and space. In this historical process, the constitution of the group is understood by the way its everyday practices take place within an unstable context, permeated by expropriation and by the difficulty of socio-spatial consciousness and autonomy.

DESCRIÇÃO PETROGRÁFICA DAS ROCHAS MÁFICAS E ULTRAMÁFICAS DA UNIDADE OURO FINO, DO GRUPO NOVA LIMA, EM CAETÉ E SANTA BÁRBARA, MG

The petrographic study of rocks of Ouro Fino unit’s Nova Lima group, Greenstone Belt Rio das Velhas, on interior of Quadrilatero Ferrifero, cointains few affected samples by alterations processes. Many rocks have the primary features like lavas in pillow, tonsils and pox. The petrographic analysis classifies the rocks in tholeiitic basalt and magnesium tholeiite. Unidade Ouro Fino’s metabasalts are from ocean bottom ambiente shown by structures (pillow lava) and lithologic associations (banded iron formation and metachert). A few minerals was recognized in petrographic thin section allowing the description of its mineral paragenese and a needed classification.The geochemical characteristics consulted in the literature indicate that part of the metabasalts was formed by a mantle plume (P-MORB). These characteristics infer a submarine plateau ambient.

Sensitivity analysis and pre-feasibility of reprocessing Au from a tailings dam in the Iron Quadrangle - The case of the Cocoruto Dam, Nova Lima, Minas Gerais

Sensitivity analysis and pre-feasibility of reprocessing Au from a tailings dam in the Iron Quadrangle - The case of the Cocoruto Dam, Nova Lima, Minas Gerais

Surface Waterproofing Techniques: A Case Study in Nova Lima, Brazil

Considering the various problems caused by infiltration in civil construction, this study aimed to identify the most appropriate waterproofing methods for different types of surfaces. A study was conducted on the mechanisms of water infiltration on surfaces and the waterproofing methods available on the market, focusing on asphalt blankets, in addition to a literature review highlighting state-of-the-art methods on this topic. A case study was also conducted in a residence in Nova Lima, Brazil, analyzing different waterproofing techniques, including their characteristics and stages. Among the conclusions, it is highlighted that the implementation of adequate project, installation, inspection, and maintenance techniques can significantly reduce the waterproofing failure rate and repair costs, and that the excellent choice of materials, along with the skill of the labor force in the application, is fundamental to guarantee the adequate performance of these materials in buildings.

Struggling over Serra do Curral

The Serra do Curral is a mountain range that extends to the municipalities of Belo Horizonte, Sabará and Nova Lima, in Minas Gerais state, Brazil. It is already deteriorated by a long history of mineral extraction not followed by any environmental restoration. Since the 1960’s, Serra do Curral has been an object of many civil society collective actions calling for its preservation. In 2022, the authorization of new mining operation provoked a strong civil society reaction. A coalition of environmental and social activists, alongside new political actors convened in defence of Serra do Curral now demand the immediate revocation of the licence. The present article analyses the current conflict, identifying the main actors, their collective action repertoires, and how those actions play out as the conflict unfolds. The research is conducted through documental inquiry, media coverage analysis and on-site direct observation. Looking into the political struggle around new-extractivism conflicts, we argue, can provide important data and insights about resistance and the developing of alternatives.

Geochemistry and mineralogy of auriferous tailings deposits and their potential for reuse in Nova Lima Region, Brazil

Since the mid-nineteenth century, gold ores, mainly hosted in sulfides, have been processed at metallurgical plants located in Nova Lima, Brazil. The generated wastes have been accumulated over the years in tailings dams or in piles. These materials represent wasted from old circuits, as well as from plants still in production. In this study, geochemical, mineralogical, 3D modelling, and metallurgical analyses wastes were carried out to evaluate potential reuse of these wastes. The performed characterization detected residues of very fine grain size containing sulfides and oxides. The wastes show high grades of Au hosted in different minerals. In addition to Au, samples contain S, Fe, Zn, Pb, Sc, Si, and As. The 3D modelling for spatial definition of Au was performed using ordinary kriging with dimensional variograms. The results indicated the occurrence of Au enrichment zones and allowed to reveal the most attractive tailing deposits in terms of Au content. Metallurgical tests showed recovery of 70% of Au and suggested other potential reuse of the wastes, such as aggregates for the civil construction sector and recovery of other metals. The present work highlights the importance of an integrative characterization within the scope of the circular economy and the value of tailings in the production chain of the mineral sector.

Sport and leisure public policy in nova lima: from agenda setting to implementation

Studies on the topic of public policies have grown in the academic environment. Understanding the policies developed in our reality is an important step in this direction. This text aims to analyze the implementation process of the public policy of sports and leisure in the city of Nova Lima. It ranges from the identification of the problem and the establishment of the political agenda for the issue. The used methodology was the analysis of documents and semi-structured interviews with the managers of the Municipal Secretariat of Sports and Leisure - SEMEL, of the city of Nova Lima in the past two administrations. As results we can consider that the agenda is formed from the demand arising from different spaces and subjects, characterizing visible players influencing decision making as to which problems or issues will comprise the political agenda. It is feasible to consider that sports and leisure policies in the city of Nova Lima are close to the top down model.

Registration of Off-Road Practices as Intangible Heritage and Implementation of the Off-Road Ecomuseum in Nova Lima, Minas Gerais

The project for Registration of off-road practices as intangible heritage and implementation of the Off-Road Ecomuseum in Nova Lima is a popular initiative that seeks to safeguard tradition and the benefits generated by off-road practices on the city's trails. This is a pioneer initiative in the country and has a multidisciplinary character, as it involves three major areas: sport, culture and tourism. From the first indigenous occupations in Minas Gerais, through pioneers, pathfinders, drovers, rural producers who transported their items for sale and to local markets to the present day, the trails of Nova Lima are traveled by sportsmen and tourists. Thus, the aim is to use the trails from their conception as places of memory Keywords: Ecomuseum, culture, tourism, ecotourism, territory.

Study of the relationship between mineralogical types and potential radon in rocks of the region of Serra do Gandarela – Quadrilátero Ferrífero-MG.

The Quadrilátero Ferrífero (QF) is one of the most well-known metallogenetic provinces in the world and has its geological context well studied since the end of the 17th century. The Serra do Gandarela is positioned in the northeast of the QF and is supported by units of the Minas Supergroup. The Moeda Formation (MF) in the Serra do Gandarela hosts an uranium (U) occurrence which was recently characterized in terms of mineralogical context. Uraninite, coffinite and brannerite are the main U minerals present. It is expected that mineralogy and lithology contribute to radon emanation and exhalation, the radon (Rn) transport from the soil to the atmosphere. In this work, the Rn exhalation was correlated to the lithological types. Samples from the MF conglomerates and Nova Lima group schists were collected from the Serra do Gandarela. Rn exhalation measurements were performed on the samples with AlphaGUARD detector. These values were compared to the U content of samples obtained via INAA. The result of INAA was more expressive in the MF conglomerate sample from the NUCLEBRÁS drillcore, with a U concentration value of 24 µg.g-1. The sample that had the highest average exhalation rate was also the same. The lowest value presented for both U concentration and average exhalation rate was shale, which were, 2 µg.g-1 and 180 Bq.m-3, respectively. The results are relevant for exploration and mining activities, during which Rn can accumulate in galleries. Additionally, the knowledge of the characteristic emanometric can be an important tool for geological and environmental studies.

Sources of auriferous fluids associated with a Neoarchean BIF-hosted orogenic gold deposit revealed by the multiple sulfur isotopic compositions of zoned pyrites

Internal textures, multiple sulfur isotopic compositions, and contents of gold, selenium, and molybdenum of ore-related pyrites from a Neoarchean carbonate-facies BIF-hosted gold deposit in Quadrilatero Ferrifero were investigated to elucidate the source(s) of sulfur. Sodium hypochlorite etching and BSE imaging revealed pervasive zoning in pyrites. Five different growth zones (Py1a, Py1b, Py2, Py3, and Py4) and six types of zoning (Type A–Type F) were identified. Two pyrite generations were distinguished in ores: G1 (Py1a and Py1b) and G2 (Py2, Py3, Py4). Both G1 and G2 have positive Δ33S, but the magnitudes of G1 are higher. The G1-relevant fluids can be shallow-sourced, whereas the G2-related auriferous fluids are most likely deep-sourced metamorphic fluids derived from devolatilization of the lower succession of the Nova Lima Group (metavolcanics and metasedimentary rocks) during metamorphism, with fluid–rock interactions during fluid ascent and at the depositional site. The negative δ34S, higher selenium contents, and carbonates inclusions of Py1a contrast with the positive δ34S, lower selenium contents, and carbonaceous material inclusions of Py2, Py3, and Py4. The Lamego system possibly started with shallow-sourced oxidized and low-gold fluids (Py1a), closely followed by mixing in of deep-seated reduced auriferous fluids (Py2, Py3, Py4) initiated by tectonic activities. The oscillatory zoning of Py2 with the highest gold contents consists of alternating gold-rich and gold-poor laminae, indicating that fault-valve activity is a trigger of gold deposition. The sulfidation of siderite in BIF (desulfidation of auriferous fluids) related to the formation of ore-related pyrites also contributed to gold precipitation.

Caracterização dos Sistemas Aquíferos do Distrito Ferrífero de Itabira, Minas Gerais

Este estudo pretende contribuir para o conhecimento hidrogeológico da região e o melhor entendimento do funcionamento deste sistema aquífero e de suas inter-relações com os demais aquíferos. A escolha desta região para o estudo baseou-se em um conjunto de características incluindo: a representatividade geológica, as grandes reservas de minério de ferro e os grandes empreendimentos minerários, existência de estudos realizados pelas mineradoras e importância das águas subterrâneas para o abastecimento de água do município. Foram identificados os seguintes sistemas aquíferos: Sistema Aquífero Coberturas Detríticas, Sistema Aquífero das Rochas Ultrabásicas, Sistema Aquífero Galho do Miguel, Sistema Aquífero Membro Campo Sampaio, Sistema Aquífero Sopa Brumadinho, Sistema Aquífero Gnáissico-Granítico, Sistema Aquífero Piracicaba, Sistema Aquífero Itabira, Sistema Aquífero Nova Lima, Sistema Aquífero Gnáissico-Granítico. Os poços mais produtivos são os perfurados nas formações ferríferas do Cauê, (Qmédia=41,75 m3/h)), seguidos pelos poços perfurados dos quartzitos do Grupo Piracicaba (Qmédia=34,01 m3/h) e, por fim, os poços menos produtivos são os perfurados nas rochas do Grupo Nova Lima e Complexo Granito-Gnáissico (Qmédia=13,30 m3/h).

Landslide susceptibility mapping using the statistical method of Information Value: A study case in Ribeirão dos Macacos basin, Minas Gerais, Brazil.

This research study was developed in the Ribeirão dos Macacos basin at the district of Nova Lima, Minas Gerais state, Brazil. The information value statistical method was applied in the construction of the landslide susceptibility map at the 1:25,000 scale. Different partitions of the inventory were tested, as well as different landslide predisposing factors. In the construction of the landslide inventory, the south, southeast and south-west slopes generally present a higher quality in aerial / orbital images due to the position of the sun (lighting direction), which emphasizes the surface structures and it may omit old landslides on slopes facing north, northeast, and northwest. This condition can generate misleading models when using the slope aspect. Another verification was that the models with better Area Under the Curve index will not always restrict the high susceptibility class in smaller areas. This incongruence occurs due to the different curve conformations, since a smaller index curve can present more restrictive results than a larger index curve. The results showed that the model has a high capacity of adjustment to the input data and high landslide predictive capacity.

Depositional setting and U-Pb detrital record of rift-related deposits in the Moeda Formation (Minas Supergroup) at the Gandarela and Ouro Fino synclines, Quadrilátero Ferrífero, Brazil

Abstract The Moeda Formation (Caraca Group, base of Minas Supergroup) registers the initial rift stages of the Minas Basin in the Quadrilatero Ferrifero, Southern Sao Francisco craton, SE-Brazil. We present stratigraphic and U-Pb detrital zircon dating analyses of the Moeda Formation that contribute to the comprehension of its sedimentary evolution in the southernmost Gandarela and Ouro Fino synclines (Central-Eastern Quadrilatero Ferrifero). The Moeda Formation sequence consists of a basal proximal alluvial fan with clast-supported conglomerates, grading upward into an alluvial floodplain with quartz arenites, and upper massive sandstones from distal fluvial fans. Because the Moeda Formation is normally limited by similar lithologies at both its base (Nova Lima Group, Rio das Velhas Supergroup) and top (Batatal Formation, uppermost Caraca Group) and stratigraphic inversion has occurred in the study area, U-Pb detrital zircon dating was also extended to these units to differentiate them stratigraphically. The youngest clusters of detrital zircon ages in the Nova Lima Group and Moeda and Batatal formations were 2716, 2777 and 2786 Ma, respectively. Based on our data and relevant literature, the depositional age of the Moeda Formation was interpreted as between 2716 and 2520 Ma with the Mesoarchean continental crust, the Rio das Velhas Supergroup and the Archean TTG complexes as its main source areas.

Mineralogical and Geochemical Characterization of Gold Mining Tailings and Their Potential to Generate Acid Mine Drainage (Minas Gerais, Brazil)

For more than 30 years, sulfide gold ores were treated in metallurgic plants located in Nova Lima, Minas Gerais, Brazil, and accumulated in the Cocoruto tailings dam. Both flotation and leaching tailings from a deactivated circuit, as well as roasted and leaching tailings from an ongoing plant, were studied for their acid mine drainage potential and elements’ mobility. Detailed characterization of both tailings types indicates the presence of fine-grain size material hosting substantial amounts of sulfides that exhibit distinct geochemical and mineralogical characteristics. The samples from the ongoing plant show high grades of Fe in the form of oxides, cyanide, and sulfates. Differently, samples from the old circuit shave higher average concentrations of Al (0.88%), Ca (2.4%), Mg (0.96%), and Mn (0.17%), present as silicates and carbonates. These samples also show relics of preserved sulfides, such as pyrite and pyrrhotite. Concentrations of Zn, Cu, Au, and As are higher in the tailings of the ongoing circuit, while Cr and Hg stand out in the tailings of the deactivated circuit. Although the obtained results show that the sulfide wastes do not tend to generate acid mine drainage, leaching tests indicate the possibility of mobilization of toxic elements, namely As and Mn in the old circuit, and Sb, As, Fe, Ni, and Se in the tailings of the plant that still works. This work highlights the need for proper management and control of tailing dams even in alkaline drainage environments such as the one of the Cocoruto dam. Furthermore, strong knowledge of the tailings’ dynamics in terms of geochemistry and mineralogy would be pivotal to support long-term decisions on wastes management and disposal.

The Archean Rio das Velhas greenstone belt revisited: new insights into the stratigraphy

The Neoarchean Rio das Velhas greenstone belt (RVGB), southeast Brazil, contains major tectonic and stratigraphic discontinuities that allow its division into three fault-bound tectonostratigraphic blocks named Santa Barbara, Nova Lima-Caete and Sao Bartolomeu. Detailed 1:25,000 scale mapping of the RVGB northern part revealed that each block contains important particularities and were subdivided into different lithostratigraphic formal units. The Santa Barbara block comprises the basal ultrabasic rocks of the Quebra Osso Group, followed by metavolcano-sedimentary successions of the Nova Lima Group (Vigario da Vara, Santa Quiteria, and Corrego do Sitio formations), and metasedimentary rocks of the Maquine Group (Palmital and Casa Forte formations). The Nova Lima-Caete block comprises the basal ultrabasic/basic volcanism (Ouro Fino and Morro Vermelho formations), metavolcano-sedimentary sequences (Mestre Caetano and Ribeirao do Brumado formations) of the Nova Lima Group, and the upper clastic sedimentary rocks of the Maquine Group (Palmital and Casa Forte formations). The Sao Bartolomeu block has a distinct rock assemblage given by metasedimentary rocks of the Nova Lima Group (Fazenda Velha, Corrego da Paina, and Pau D'Oleo formations), and clastic sedimentary rocks of the Maquine Group (Andaimes Formation). Despite some remarkable differences between these blocks, it is possible to recognize stratigraphic correlations and similar depositional evolution. The authors suggest volcanic architecture and sedimentary depositional models for the studied area, which includes: i) fissure eruption of komatiite lavas of the Quebra Osso Group in the SB block with subordinate clasto-chemical sedimentation; ii) ultrabasic/basic volcanism related to multiple volcanic centers in a subaqueous environment, characteristic from the basal portion of the Nova Lima Group in the SB and NLC blocks; iii) intermediate to acid volcanic and volcaniclastic rocks from the Nova Lima Group, present only in the NLC block, related to explosive eruptions; iv) clasto-chemical sedimentation, well recorded in the SB block; v) thick sequence of clastic sediments recorded in the three blocks with a predominance of greywacke-argillite cycles, deposited by turbidity currents in tectonically active submarine basins; vi) metasediments formed in alluvial-fluvial, coastal and shallow marine environments of the Maquine Group.

Structural Evolution of the Rio das Velhas Greenstone Belt, Quadrilátero Ferrífero, Brazil: Influence of Proterozoic Orogenies on Its Western Archean Gold Deposits

The Quadrilátero Ferrífero region is located in the extreme southeast of the Brasiliano São Francisco craton, Minas Gerais state, Brazil. It is composed of (i) Archean TTG granite-gneaissic terranes; (ii) the Archean Rio das Velhas greenstone belt; (iii) the Proterozoic metasedimentary and metavolcano-sedimentary covers. The Rio das Velhas rocks were deposited in the synformal NW–SE-directed Nova Lima basin. The Archean deformation converted the Nova Lima basin into an ample synclinorium with an eastern inverted flank. Archean orogenic gold mineralization within the Rio das Velhas greenstone belt rocks is controlled by NNW–SSE-directed, Archean regional shear zones subparallel to the strata of the Nova Lima synclinorium borders. Transamazonian and Brasiliano orogenies are superposed onto the Archean structures that control gold mineralization. In the eastern domain, Brasiliano fold-and-fault belts prevail, whereas in the western domain Archean and Transamazonian structures abound. The present study focus mainly is the western domain where the Cuiabá, Morro Velho, Raposos, Lamego and Faria deposits are located. Gold orebodies plunge to the E–NE and are tectonically controlled by the Archean D1–D2 deformation. The D3 Transamazonian compression—Which had a SE–NW vector sub-parallel to the regional mineralized Archean foliation/bedding—Buckled these structures, resulting in commonly open, synformal and antiformal regional folds. These are well documented near the gold deposits, with NE–SW axial traces and fold axes plunging to E–NE. Such folds are normal to inverted, NW-verging, with an axial planar foliation dipping moderately to the SE. The Transamazonian compression has only been responsible for the reorientation of the mineralized Archean gold ores, due to coaxial refolding characterized by an opposite tectonic transport. It has therefore not caused any other significant changes. Thrust shear zones, sub-parallel to the strong Transamazonian foliation, have given rise to localized metric segmentation and to the dislocation of gold orebodies. Throughout the region, along the towns of Nova Lima to Sabará, structures pertaining to the Brasiliano Araçuaí orogeny are represented only by gentle folding and by a discrete, non-pervasive crenulation cleavage. Thrust-shear zones and small-scale normal faults have caused, at most, metric dislocations along N–S-oriented planes.

Gestão de desastres em Turismo

O presente trabalho irá discutir a percepção dos agentes locais de turismo, Secretaria de Turismo de Nova Lima e Defesa Civil de Nova Lima sobre a gestão de desastres em turismo no distrito de São Sebastião das Águas Claras e o impacto causado no turismo local devido a ameaça de rompimento da barragem de rejeitos B3/B4 da mineradora Vale S.A. Para tanto abriu-se uma discussão sobre conceitos de desastre, o papel da Defesa Civil na gestão de riscos e desastres, a redução de riscos de desastres em turismo e sobre a colaboração dos stakeholders. Com o intuito de atingir os objetivos da pesquisa, a partir de entrevistas realizadas em campo, buscou-se compreender os impactos causados no turismo pela ameaça de rompimento da barragem no distrito. Também foi discutido quais as medidas de prevenção foram adotadas pelas autoridades governamentais e empresa Vale S.A. Além disso, foi discutido a colaboração entre os stakeholders como forma de diminuir os impactos no turismo. Como conclusão, foi possível observar que a percepção dos agentes locais de turismo conflita com as percepções dos órgãos públicos e que a gestão de desastres em turismo no distrito não foi e não tem sido eficaz.

Urban Expansion and Erosion Processes in an Area of Environmental Protection in Nova Lima, Minas Gerais State, Brazil

The growth of the real estate market is considered one of the leading economic indicators of city development. The pressure for new sites for the construction of buildings and houses causes significant and severe socio-environmental impacts. The municipality of Nova Lima is conurbated with Belo Horizonte, the capital of Minas Gerais State, Brazil. In recent decades, the municipality of Nova Lima has been attracting real estate developers of luxury housing because of its favored location in a valley surrounded by mountain ranges with stunning landscapes. This study aimed to evaluate the emergence and evolution of erosive processes in a region of high real estate pressure in the municipality of Nova Lima, Minas Gerais State, Brazil. The study site is considered an area of environmental protection, belonging to the “Cardoso” river basin, a tributary of the “das Velhas” river. The images of the area were obtained by an “unmanned aerial vehicle”, with flights performed in 2019. Orthomosaic, digital surface and elevation models were obtained from these images. Historical series of satellite imagery provided by Google Earth were also used, as well as a survey of secondary data on the use and soil occupation of the region. The intense expansion of the real estate sector in metropolitan areas put pressure on environmental preservation in peri-urban areas. In this study, erosion processes and gullies were observed as a result of the construction of luxury residences. Construction residues of the buildings were disposed on the floor of a valley, burying the source of the “Estrangulado” Stream. The appearance of gullies is attributed to a combination of factors such as the removal of vegetation cover, the irregular disposal of construction waste in an environmental protection area, an insufficient drainage system for rainwater, and the lack of water collection and treatment of domestic wastewater. Over the years, the dimensions of gullies have increased and can cause damage to the buildings there. Also, the soil and sediment washed away by the runoff will affect the volume and quality of water in a watershed that is essential for supplying the metropolitan region of Belo Horizonte, Minas Gerais, Brazil.