Assessing how the disturbances affect the physical structure and biodiversity of freshwater ecosystems has become a critical research priority. Bauxite mining is economically important in the Amazon, but associated infrastructure may influence freshwater biodiversity. We evaluated the effects of a bauxite ore pipeline on the community structure of semiaquatic bugs (Heteroptera: Gerromorpha) in 40 streams of the eastern Amazon, including 20 sites crossed by the pipeline and 20 control sites. We tested whether (i) species abundance and richness upstream and downstream of control sites would be higher than in pipeline sites, (ii) upstream sites would show greater abundance and richness due to species sensitivity and habitat alteration in sites crossed by the pipeline, (iii) community composition would differ between pipeline and control sites, with characteristic species for each treatment, and (iv) the pipeline would indirectly influence communities through changes in habitat quality, riparian cover, and abiotic variables. Multivariate analyses indicated clear differences in community composition, with indicator species characterizing each condition, including the species Rhagovelia jubata in pipeline streams and Stridulivelia alia and Stridulivelia strigosa in control streams. Abundance showed a tendency to be higher in control streams, whereas richness was associated with abundance but not with habitat integrity. These findings indicate that, although diversity metrics remained similar, pipeline installation is linked to changes in species composition, reflecting shifts in local environmental conditions.

The Amazon basin is undergoing rapid environmental transformation driven by agricultural expansion and mining activities, resulting in increased concentrations of toxic metals in aquatic ecosystems. This study quantified arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in six fish species and evaluated associated noncarcinogenic and carcinogenic health risks under two consumption scenarios: the Amazon Scenario (462 g/person/day) and the Brazil Scenario (24 g/person/day). Fish were sampled in five municipalities in western Pará, which differ in the intensity of the gold and bauxite mining activities. The results show that Hg concentrations exceeded legal limits in most carnivorous species; the target hazard quotients (THQ) indicate lifelong noncarcinogenic risk (THQ > 1) in nearly all samples under the Amazon Scenario, peaking at 28.97 for Cichla ocellaris from Porto Trombetas. Total target hazard quotients (TTHQs) also exceeded the safety threshold of 1 for all species in the Amazon Scenario, indicating significant noncarcinogenic risk for local consumers, whereas risks remained acceptable under the national consumption pattern. Carcinogenic risk analysis revealed that 25% of samples in the Amazon Scenario exceeded the 1 × 10-4 threshold, primarily due to arsenic exposure. These findings demonstrate that traditional fish-based diets expose Amazonian riverine populations to hazardous levels of potentially toxic elements, underscoring the need for integrated environmental monitoring, public health surveillance, and nutritional guidance tailored to high-consumption communities.

Eriochrome black T degradation by photo-Fenton process in heterogeneous Fe-zeolite synthesized from bauxite mining waste

PT. Bumi Khatulistiwa Bauksit (PT. BKB), a bauxite mining company, faces challenges in maintaining its tailing ponds. The lack of a structured maintenance schedule has led to sediment accumulation, which risks pond shallowing and environmental contamination from potential overflow. This study aims to evaluate the condition of the settling ponds and establish an optimal maintenance schedule. A quantitative approach was employed, combining primary field data with secondary data. Analytical steps included calculating design rainfall, rainfall intensity, total discharge, solid percentage, settling velocity, and maintenance/dredging time based on pond volume and sediment accumulation. Results indicate the highest daily total discharge in Pond 1 (17,276.23 m³/day) and the lowest in Pond 5 (5,022.97 m³ /day). Maintenance intervals vary: Pond 1 requires dredging every 1 month and 7 days; Pond 2, every 1 month and 22 days; Pond 3, every 1 year and 5 months and 12 days; Pond 4, every 4 months and 18 days; and Pond 5, every 6 years and 5 months and 12 days. The excavator’s productivity reaches 447.93 m³/hour, with dredging time per pond ranging from 8 to 35 days.

The mineral-mapping capability of three spaceborne sensors with different spatial and spectral resolutions, the Environmental Mapping and Analysis Program (EnMap), Sentinel-2, and World View-3 (WV3), is assessed regarding bauxite mining wastes in Amphissa, Greece, with validation based on ground samples. We applied the well-established Linear Spectral Unmixing (LSU) and Spectral Angle Mapping (SAM) classification techniques utilizing endmembers of two established spectral libraries and incorporated ground data through geochemical and mineralogical analyses, X-ray fluorescence (XRF), Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), and X-ray Diffraction (XRD), to assess classification performance. The main lithologies in this area are bauxites and limestones; therefore, aluminum oxyhydroxides, calcite, and iron oxide minerals were the dominant phases as indicated by the XRF/XRD results. Almost all target minerals were mapped with the three sensors and both methods. The performance of EnMap is affected by its coarser spatial resolution despite its higher spectral resolution using these methods. Sentinel-2 is most effective for mapping iron-bearing minerals, particularly hematite, due to its higher spatial resolution and the presence of diagnostic iron oxide absorption features in the VNIR. World View 3 Shortwave Infrared (WV3-SWIR) performs better when mapping calcite, benefiting from its eight SWIR spectral bands and very high spatial resolution (3.7 m). Hematite and calcite yield the highest accuracy, especially with SAM, indicating 0.80 for Sentinel-2 (10 m) for hematite and 0.87 for WV3-SWIR (3.7 m) for calcite. AlOOH shows higher accuracy with SAM, ranging from 0.57 to 0.80 across the sensors, while LSU shows lower accuracy, ranging from 0.20 to 0.73 across the sensors. This study showcases each sensor’s ability to map minerals while also demonstrating that spectral coverage and the spatial and spectral resolution, as well as the characteristics of the selected endmembers, exert a critical influence on the accuracy of mineral mapping in mine waste.

The abandoned bauxite mine (ABM) soil is a major global environmental issue. ABM soil is nutrient-deficient and abundant with several contaminants, hefty metals (HMs). Therefore, restoring ABM soil with suitable plants is of utmost concern in terms of both economic and environmental benefits. Jatropha curcas (JC) and Chrysopogon zizanioides (CZ) are effective in phyto‑stabilization of contaminated and mining‑affected soils, offering significant benefits such as climate resilience, energy production, erosion control, and prevention of leaching. The present study investigates the effects of JC and CZ grown in ABM soil. JC and CZ were examined for overall growth performance, biochemical response, antioxidant compounds, metal tolerance of HMs and enhancement of overall soil quality after cultivation. The study was carried out for 120days using ABM soil amended with different ratios of garden soil (GS). The treatments taken were T0 (100% GS) as control, T1 (75% GS + 25% ABM soil), T2 (50% GS + 50% ABM soil), T3 (25% GS + 75% ABM soil) and T4 (100% ABM soil), completely randomized design with 4 replications adopted. There was a highest shoot length (45.5cm) in JC, young and mature leaves (4.25 and 15), and basal diameter (13.11mm) in T2. In CZ. The highest shoot length was in T1 (109.63cm), and the number of tillers increased steadily, reaching 3.75 (T1). The above- and below-ground biomass of JC and CZ increased the most in T2 (6.44% and 16.95%) and T1 (5.08% and 11.94%), respectively, compared to the control. JC and CZ accessions exhibited more or less a significant increase (p < 0.05) in defence mechanisms, including proline, malonaldehyde, superoxide dismutase and catalase activities when exposed to different amendments of ABM soil. After cultivation of JC and CZ, overall soil nutrients improved, and HMs concentrations decreased across treatments. In JC, Al, Fe and Mn showed strong negative correlations with carbohydrate and protein contents (p < 0.01; p < 0.05). Additionally, Cr, Cu, Ni and Zn were negatively correlated with CAT (p < 0.05). In CZ, Al, Fe, Cr and Ni exhibited significant negative correlations with total chlorophyll, carotenoids, carbohydrates and proteins (p < 0.01).

This article focuses on studying the phase transformation of bauxite iron minerals during electrolytic reduction processes in alkaline solutions (400 g/L Na2O), with the aim of improving aluminum extraction in the subsequent Bayer process. The research employs electrolytic reduction to convert the refractory minerals in unmilled bauxite (alumogoethite (Fe,Al)OOH, alumohematite (Fe,Al)2O3, chamosite (Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8) into magnetite, elemental iron (Fe) and to minimize aluminum (Al) extraction during electrolysis. Preliminary thermodynamic research suggests that the presence of hematite (α-Fe2O3) and chamosite in boehmitic bauxite increases the iron concentration in the solution. Cyclic voltammetry revealed that, in the initial stage of electrolysis, overvoltage at the cathode decreases as metallic iron deposited and conductive magnetite form on the surface of the particles. After 60 min, the reduction efficiency begins to decrease. The proportion of the current used for magnetization and iron deposition on the cathode decreased from 89.5% after 30 min to 67.5% after 120 min. After 120 min of electrolytic reduction, the magnetization rate exceeded 65%; however, more than 60% of the Al was extracted simultaneously. Al extraction after electrolysis and subsequent Bayer leaching exceeded 91.5%. Studying the electrolysis product using SEM-EDS revealed the formation of a dense, iron-containing reaction product on the particles’ surface, preventing diffusion of the reaction products (sodium ferrite and sodium aluminate). Mössbauer spectroscopy of the high-pressure leaching product revealed that the primary iron-containing phases of bauxite residue are maghemite (γ-Fe2O3), formed during the hydrolysis of sodium ferrite.

ABSTRACT Field-based monitoring may be insufficient to detect biodiversity trends across scales, especially in projects that have the potential to impact extensive areas. Despite its importance, landscape-scale data collection is rare in impact monitoring practice. In this research, we tested landscape metrics to evaluate their contribution to enhancing forest biodiversity monitoring in the EIA follow-up process, using a case study of a bauxite mine in the Brazilian Amazon. The research combined literature review and a case study to select, apply, and compare landscape metrics with local-scale field-based biodiversity monitoring. Metrics related to the amount and quality of habitats, fragmentation, edge effect extent and connectivity of landscape were selected and evaluated. We found that they can be easily incorporated into EIA follow-up, as they rely on readily available remote sensing time series, enabling the construction of historical baselines even prior to project approval. Also, landscape metrics can complement field-based surveys by detecting spatial patterns and offering opportunities for integrated multi-scale biodiversity assessments. Furthermore, they provide valuable inputs for identifying, planning, and spatially allocating offsets and additional conservation actions, thereby contributing to more effective impact mitigation and supporting stronger biodiversity outcomes.

This study focuses on the Lujiang Alum Mine, analyzing sources of acid mine drainage (AMD) generated during remediation activities. A numerical model of groundwater flow was constructed to simulate and predict the causes of AMD under the influence of remediation measures. Concurrently, hydrogen and oxygen stable-isotope-tracing techniques were employed to elucidate the pathways through which AMD occurred and the mechanisms underlying water acidification. A fully mixed model was established to quantify the rates of contribution from different water sources. The results indicate that the annual amount of acidic wastewater produced under the influence of disturbance via remediation is approximately 3.29 × 105 m3. The fully mixed model based on environmental isotopes further revealed that the discharge of water from the first branch of the +85 m adit serves as the primary cause of AMD during the wet, normal, and dry seasons, with a contribution exceeding 50%. This is followed by recharge from Tianchi Lake, accounting for approximately 20–30%. In contrast, the contributions from seepage water from the roof of the +85 m adit and water from the Xiaofanshan Inclined Shaft are relatively minor. Based on these findings, we propose targeted strategies for source prevention and end-of-pipe treatment of AMD in the mining area. This work provides scientific support for the ongoing ecological restoration project at the Lujiang Alum Mine and offers valuable insights for AMD management in similar mines.

Tayan Hilir District, West Kalimantan Province, Indonesia, is characterized by the presence of economically valuable mineral resources, particularly bauxite deposits. This study aims to delineate the distribution of bauxite deposits in Sebemban Village, Tayan Hilir District, using integrated geophysical approaches. The investigation employed the induced polarization (IP) and electrical resistivity methods with a dipole–dipole electrode configuration. Resistivity and chargeability measurements were conducted along three survey lines, each 156 m in length with an electrode spacing of 4 m. The results show that the resistivity values range from 45.36 to 367.177 Ω·m, while the chargeability values vary between 16.9 and 878.80 ms. The subsurface stratigraphy of the study area comprises latosol, bauxite, saprolite, and bedrock units, including granodiorite and quartz diorite. Bauxite mineralization was identified at shallow depths, commencing at approximately 0.6 m below the ground surface. These results indicate that the combined application of resistivity and induced polarization methods is effective for identifying and characterizing near-surface bauxite deposits in the study area.

Analysis of the impacts of bauxite mining on the environment and the socio-economic activities of the population of the rural commune of Tanènè, Boké prefecture

Experimental Investigation into the Influence of Water Saturation on the Tensile Failure Behavior of Diaspore-Type Bauxite: Implications for Underground Mining of Bauxite

Bauxite mining exploitation in Indonesia demonstrates a serious gap between government regulation and oversight. Although a legal framework is in place through Law Number 3 of 2020 concerning Mineral and Coal Mining and its derivative regulations, its implementation remains weak due to disharmony between agencies and overlapping authority between the central and regional governments. This study aims to analyze the regulatory and oversight gaps in bauxite mining management and their implications for legal certainty and environmental sustainability. The research method used is a normative juridical approach, examining laws and regulations, legal literature, and empirical data related to mining oversight practices in several bauxite-producing regions. The results indicate that weak inter-agency coordination, a shortage of mining inspectors, and minimal transparency of production and export data are the main causes of weak oversight. Furthermore, the lack of integration between technical and environmental policies creates a gray area that business actors exploit to avoid legal obligations. This gap has resulted in increased environmental damage, legal uncertainty, and a decline in public trust in the government. Regulatory reform measures are needed through inter-agency harmonization, strengthening digital-based oversight capacity, and involving the public in evaluating mining activities to create a transparent, equitable, and sustainable mining governance system.

Bauxite mining that has been ongoing for decades in Bintan Regency, Riau Islands Province, has left several voids or former excavated ponds. The existence of these post-mining voids has the potential to affect environmental quality, especially regarding water quality components and the suitability of land use in the surrounding area. This study aims to analyze the current condition of bauxite void water quality after mining in Bintan Regency as a basis for assessing the ecological aspects of the post-mining area. The analysis was conducted descriptively and comparatively by comparing the physico-chemical water parameters against class II water quality standards, in accordance with Government Regulation Number 22 of 2021. Data were obtained from the Bintan Regency Environment Agency (DLH) in 2023, including parameters such as pH, DO, BOD, COD, TSS, TDS, Total Phosphate, and Fecal Coliform. The results showed that most of the water quality parameters were within the class II standard range, except for pH, which varied between 0.24 and 7.75, indicating that some locations were highly acidic. The pH value is the main limiting parameter in determining the ecological conditions of the post-mining voids. Based on the calculation of the compliance score, about 68.8% of voids are classified as "Appropriate," and 31.2% as "Fairly Appropriate." These findings indicate that most voids have undergone natural stabilization processes, although some still require advanced ecological rehabilitation to normalize water quality and support post-mining environmental functions.

In certain mining areas, bauxite ore exhibits high and uneven hardness, causing frequent overloads in the cutting heads of bauxite mining equipment and challenging the dynamic performance and reliability of its gear transmission system. To investigate the influence of macro-geometric parameters, a dynamic model was built using MASTA software (version 13.0.1). This study systematically analyzed the effects of pressure angle, face width, and bottom clearance coefficient on gear meshing characteristics, service life, and vibration noise under various loads. A preferred set of parameters was determined and validated through vibration and noise tests. The results show that increasing the pressure angle and face width improves gear meshing and fatigue life, while the bottom clearance coefficient has an optimal value of 0.4. Increasing the bottom clearance coefficient exacerbates vibration and noise, with other parameters causing fluctuations under different conditions. The optimal parameters of 23° pressure angle, 75 mm face width, and 0.4 bottom clearance coefficient effectively reduce vibration and noise, providing a theoretical and practical basis for improving the cutting transmission system.

Mechanical properties of minerals in high-sulfur bauxite from DFT calculation

The objective of this study was to evaluate the floristic composition, phytosociological parameters, and chemical attributes of the soil to assess the efficiency of exclusive natural regeneration for forest restoration in an area after 6 years of bauxite mining. The forest inventory was conducted for all individuals with a Circumference at Breast Height (CBH) ≥ 10 cm, and phytosociological parameters were analyzed using Fitopac 2.1 software. The area showed dominance of early succession species (pioneers and early secondary). The study revealed a low floristic diversity (H’=1.374) as well as equitability (J’=0.48), with the dominance of the genus Vernonanthura. The natural regeneration technique has proven to be efficient in soil coverage and has contributed to the recovery of soil attributes such as organic matter, soil pH, sum of bases, cation exchange capacity, total-N, and an increase in nutrients (K, Ca, Mg, Mn, and Zn). To enhance floristic diversity and expedite the restoration process in this area, we recommend controlling invasive grasses, enriching the area by planting seedlings of native species from more advanced succession stages, and employing nucleation techniques.

Ecopolitics of extractivism in natural resource-rich regions and the struggles of Indigenous communities are globally known phenomena. This article outlines the ecopolitics of extractivism leading to a development paradox, while the Indigenous Asur communities encounter the detrimental effects of mining and unfulfilled pledges of developmental agendas. Based on a qualitative research approach, it explores the lived experiences of the Asur (a Particularly Vulnerable Tribal Group) in Gumla district of Jharkhand in India. It reveals that the Asur tribal people, influenced by promises of socio-economic development and better employment opportunities, consented to the acquisition of their land for bauxite mining. However, the failure of private sector entities to fulfil these promises has contributed to the policy-enabled patterns of mineral resource exploitation. The socio-ecological compensation for the sacred Asur tribe land formed a paradoxical scenario and development dynamics. The article underscores that the preservation of land rights, environmental sustainability and social welfare for tribal people has notably been futile in India. Moreover, the extractivism leading to severe health hazards, ecological destruction, depletion of forest resources, environmental pollution and loss of livelihood within the Asur habitat evidenced from the narratives. The analysis has implications for rights-based, ecologically grounded and Indigenous community-led approaches.

Bauxite mining is a relevant source of economic and social development for countries that have this natural resource. It emerges from the findings and extensive literature reviews that this exploitation has direct impacts on estuarine ecosystems through the establishment of ports and mining industries, hence the opportunity of our study entitled " Contribution has the study of the impacts of industrial activities on the estuarine ecosystem of the Nunez River. The field observation indicates that despite the efforts made by the authorities through the competent institutions and investors, the reduction of environmental impacts caused by this mining often poses problems linked to a lack of capacity and means to deal with them, as revealed by our study carried out on the Nunez estuary. The hypothesis of our theme sufficiently proves that the negative effects of major pollutants in the Nunez River estuary due to the installation of industrial units, combined with the impacts linked to climate change affecting the locality, contribute to the dysfunction of the estuary, and consequently, to the reduction of opportunities and ecosystem services offered by the Nunez River. In addition, numerous studies have been conducted on air quality, the measurement of various physicochemical parameters (temperature, pH, electrical conductivity, salinity, turbidity, dissolved oxygen, nitrates, nitrites, suspended matter, dissolved solids and phosphate) as well as the identification and quantification of trace metal elements (Cu, Cd, Ni, Pb, and Zn) in the waters of the Nunez River. However, given the high variability of the recorded values of these physicochemical parameters, the concentrations and potential toxicity reported in the literature for these elements, it seemed necessary to study them while addressing the climatic context in which these pollution processes take place. The European Water Framework Directive has set a monitoring for metals such as cadmium, lead, nickel and mercury. However, we find it interesting to expand our research to the 5 most listed metals in environmental studies and the characteristic parameters of water in general. Thus our general objective is to study the level of pollution and its impact on the functioning of the estuarine ecosystem of the Nunez River due to the installation and operation of industrial units taking into account the evolution of the climatic characteristics of the study area. with the following specific objectives: 1) Evaluate the impact of pollution on the ecology of the Nunez estuary taking into account the evolution of climatic conditions; 2) Propose mitigation and adaptation measures in accordance with the level of pollution. ). Thus eleven sampling sites served as a study framework. These samples were analyzed at the CERE / UGANC laboratory, and at the Guinéo Allemand analysis laboratory in Landréah in Conakry. We used World Bank data for the analysis of climate variability in our study area for the period 1950-2020. The results of all these detailed analyses are presented in Chapter 3. A summary of the results, operational perspectives and possible research are also mentioned.

Mining (1) operations in remote areas (2) face significant challenges related to energy supply, high fuel costs, and limited infrastructure. This study investigates the potential for achieving energy independence (3) and resilience (4) in such environments through the integration of renewable energy sources (5) and battery–electric mining equipment. Using the “Studena Vrila” underground bauxite mine as a case study, a comprehensive techno-economic and environmental analysis was conducted across three development models. These models explore incremental scenarios of solar and wind energy adoption combined with electrification of mobile machinery. The methodology includes calculating levelized cost of energy (LCOE), return on investment (ROI), and greenhouse gas (GHG) reductions under each scenario. Results demonstrate that a full transition to RES and electric machinery can reduce diesel consumption by 100%, achieve annual savings of EUR 149,814, and cut GHG emissions by over 1.7 million kg CO2-eq. While initial capital costs are high, all models yield a positive Net Present Value (NPV), confirming long-term economic viability. This research provides a replicable framework for decarbonizing mining operations in off-grid and infrastructure-limited regions.