Sand mining from riverbeds has been a vital component of the construction industry for decades, providing a fundamental ingredient for concrete production. However, the indiscriminate extraction of sand from riverbeds led to serious environmental issues, like erosion of riverbeds, destruction of aquatic habitats and increased susceptibility to flooding which emphasizes the necessity of finding alternate materials. Recent studies on Weathered Crystalline Rock, a soft upper layer in quarries – often discarded as waste – have shown that WCR-sand could be a viable alternative to fine-aggregates in concrete thereby alleviating the environmental impacts caused by the extraction of natural resources. Five mixes of M65 grade concrete with sand replacement of 5%, 10%, 15% and 20% with WCR-sand were prepared, cured for maximum 90 days and tested for mechanical and durability properties. Results obtained led to the conclusion that WCR-sand can be a partial replacement up to 5% – theoretically and even up to 10% practically – of sand in concrete without affecting the mechanical and durability properties. This could potentially reduce sand-mining and rock-quarrying up-to 5 to 10% which not only helps curb the depletion of natural resources, a major environmental concern today, but aids in managing waste materials from quarrying. decades production However issues Rock WCRsand WCR fineaggregates fine aggregates resources M M6 10 15 20 prepared 9 properties sandmining rockquarrying rock quarrying upto today 1 2

ABSTRACT Areas impacted by the deposition of iron mining tailings present physical and chemical characteristics that can hinder root growth, and applying soil conditioners can help alleviate these limitations. The objective was to evaluate the effect of soil conditioners in improving the environment for the growth of grass in soil affected by iron mining tailing. Four different experiments were conducted testing conditioner proportions (0, 5, 10, 25, and 50% v/v), in a completely randomized design with four replications, using Cynodon spp. The conditioners were sand, vermiculite, sawdust, and organic compost. Bulk density, macro- and microporosity, total pore volume (VTP), pH, organic matter content (OM), cation exchange capacity (CEC), and dry mass of the aboveground, root, and total plant were evaluated. There were improvements in porosity and a reduction in density with the application of vermiculite, sawdust, and organic compost; however, sand decreased the VTP. The pH was reduced with sawdust and increased with compost. Sawdust and compost increased OM. CEC increased with vermiculite and compost. The sand and vermiculite conditioners promoted the greatest growth of Cynodon spp., with emphasis on vermiculite, which provided the greatest increases in plant biomass production. The soil conditioners, overall, proved effective in improving porosity conditions, reducing density, increasing OM, and promoting plant growth, this makes this technology efficient for application in tailings. Due to its notable effect on increasing biomass and improving the environment for grass growth, vermiculite can be recommended for rehabilitation environments impacted by iron mining tailings or for post-mining revegetation. limitations tailing 0, 0 (0 5 10 25 50 v/v, vv v/v , v v/v) replications spp macro microporosity VTP, VTP (VTP) OM (OM) CEC, (CEC) aboveground evaluated however production overall conditions postmining post revegetation ( 1 2 (VTP (OM (CEC

RESUMO Áreas impactadas pela deposição de rejeito de mineração de ferro possuem características físicas e químicas que podem dificultar o crescimento das raízes, e a aplicação de condicionadores pode ajudar a aliviar essas limitações. O objetivo foi avaliar o efeito de condicionadores de solo na melhoria do ambiente para o crescimento de gramínea em solo afetado por rejeitos de mineração de ferro. Foram realizados quatro experimentos testando proporções de condicionador (0, 5, 10, 25 e 50% v/v), em delineamento inteiramente casualizado com quatro repetições, utilizando Cynodon spp. Os condicionadores foram areia, vermiculita, serragem e composto orgânico. Foram avaliados densidade aparente, macro- e microporosidade, volume total de poros (VTP), pH, matéria orgânica (OM), capacidade de troca de cátions (CEC) e massa seca da parte aérea, raízes e total. Houve melhorias na porosidade e redução na densidade com a aplicação de vermiculita, serragem e composto; no entanto, a areia diminuiu o VTP. O pH foi reduzido com serragem e aumentou com composto. A serrage 6m e o composto aumentaram a OM. A CEC aumentou com vermiculita e composto. Os condicionadores de solo, de modo geral, mostraram-se eficazes na melhoria das condições de porosidade, redução da densidade, aumento de OM e promoção do crescimento das plantas, o que torna esta tecnologia eficiente para aplicação em rejeitos. Devido ao seu notável efeito no aumento da biomassa e na melhoria do ambiente para o crescimento de gramínea, a vermiculita pode ser recomendada para ambientes de reabilitação impactados por rejeitos de mineração de ferro ou revegetação pós-mineração. limitações 0, 0 (0 5 10 2 50 v/v, vv v/v , v v/v) repetições spp orgânico aparente macro microporosidade VTP, VTP (VTP) OM, (OM) (CEC aérea entanto m geral mostraramse mostraram se plantas pósmineração. pósmineração pós mineração. pós-mineração ( 1 (VTP (OM

Abstract To connect the protection of natural resources to economic development, environmental rehabilitation is a promising way to repair and compensate for impacts on biodiversity and ecosystem services. Here, we aimed to compare and select potential indicators for the success of different rehabilitating ecosystems to quantify gains in biodiversity and ecosystem services within the Impact Mitigation Hierarchy. We sampled nine environmental variables along rehabilitation chronosequences from rehabilitating (i) iron mining waste piles, (ii) sand quarries, and (iii) compensation areas in the Carajás National Forest. From that, we computed the rehabilitation status, i.e., the proportion of environmental enhancements compared to the overall rehabilitation trajectory, and statistically validated the indicators that best described the status. With a mean rehabilitation status for the oldest rehabilitation stages from waste piles, sand quarries, and compensation areas of 52, 71, and 74%, respectively, we confirmed that rehabilitation activities were able to generate considerable gains in biodiversity. In all the cases, the Shannon diversity, phylogenetic diversity and Leaf Area Index performed better than did the other indices, encouraging the increased use of these indices for upscale monitoring activities. Consistent indicators across distinct projects highlight the importance of maximizing tree diversity and canopy closure in rehabilitation projects to increase biodiversity gains within Impact Mitigation Hierarchy. development Here Hierarchy i (i piles ii (ii quarries iii (iii Forest ie e i.e. trajectory 52 71 74 74% respectively cases i.e 5 7

ABSTRACT An important source of coniotic air pollution is mining activity in quarries, what produces large quantities of particulate matter that affects human health and ecosystems. The purpose of this work is to determine by the gravimetric method, the content of fines (particles smaller than 0.074 mm) in the unpaved roads from the front of "La Molina" quarries to production centers from Canteras Mariel Base Business Unit as well as in the aggregate storage piles. Samples of 30 g taken at 11 points of the unpaved roads and in the piles of each type of aggregate (granite, sand, gravel and macadam) were analyzed. A 24 .9% concentration of average fines for unpaved roads, a figure that doubles the values reported in the literature for extractive activities. It was also found that due to the action of wind and rain, these fines adhere mostly to the assortments of greater granulometry arranged in piles, what causes the production to be contamination to be contaminated.

RESUMEN La actividad minera en las canteras es una fuente importante de contaminación coniótica del aire al producir grandes cantidades de material particulado que afectan la salud humana y los ecosistemas. El presente trabajo tuvo por objetivo determinar, por el método gravimétrico, el contenido de finos (partículas menores de 0,074 mm) en los caminos no pavimentados desde el frente de canteras "La Molina” hasta los centros productivos de la Unidad Empresarial de Base Canteras Mariel, así como en las pilas de almacenamiento de los áridos. Se analizaron muestras de 30 g tomadas en 11 puntos de los caminos no pavimentados y en las pilas de cada tipo de árido (granito, arena, gravilla y macadam). Se obtuvo un 24,9 % de concentración de finos promedio para los caminos no pavimentados, cifra que duplica los valores reportados en la literatura para actividades de carácter extractivo; igualmente se encontró que esos finos se adhieren mayormente, por la acción del viento y la lluvia, a los surtidos de mayor granulometría dispuestos en pilas, propiciando la contaminación de las producciones.

ABSTRACT The objective of this work was to evaluate the growth in plant height, stem base diameter, survival rate, and ecophysiology of Acacia mangium and Mimosa caesalpiniifolia plants with and without inoculation with arbuscular mycorrhizal fungi (Rhizophagus clarus) in areas degraded by mining in the municipality of Itaporanga D’Ajuda, SE, Brazil. The experiment was conducted with plants grown with spacing of 3 × 3 m in areas degraded by sand and gravel mining in Itaporanga D’Ajuda, using plants of the species Acacia mangium and Mimosa caesalpiniifolia. Four treatments were used: Acacia mangium without AMF; Mimosa caesalpiniifolia without AMF; Acacia mangium with AMF; Mimosa caesalpiniifolia with AMF. Plants from each treatment were evaluated for plant height, stem base diameter, survival rate and ecophysiological parameters at 12 months after planting. The forest legume Mimosa caesalpiniifolia inoculated with mycorrhizal fungi (Rhizophagus clarus) presented the best results in plant height, survival rate, and photosynthetic efficiency, at twelve months after planting. Plants in the treatment with Acacia mangium without inoculation with mycorrhizal fungi (Rhizophagus clarus) had the largest stem base diameters and second highest plant heights. However, the lowest survival rate of the plants may have caused overestimation of the results of stem base diameter and plant height. height Rhizophagus clarus DAjuda, DAjuda D Ajuda, Ajuda D’Ajuda SE Brazil used AMF 1 planting efficiency heights However

RESUMO O objetivo deste estudo foi avaliar o crescimento em altura, diâmetro, a taxa de sobrevivência e a ecofisiologia de Acacia mangium e Mimosa caesalpiniifolia inoculadas com fungos micorrízicos arbusculares (Rhizophagus clarus) e sem inoculação em área degradada de mineração no município de Itaporanga D’Ajuda, SE. O experimento foi implantado no espaçamento de 3x3 m em uma área degradada por mineração de areia e cascalhos no município de Itaporanga D’Ajuda, SE com as espécies Acacia mangium (Acacia) e Mimosa caesalpiniifolia (Sabiá). Foram definidos quatro tratamentos: Acacia mangium sem FMA; Mimosa caesalpiniifolia sem FMA; Acacia mangium com FMA; Mimosa caesalpiniifolia com FMA. As plantas de cada tratamento foram avaliadas quanto à altura da planta, diâmetro da base do caule, taxa de sobrevivência e parâmetros ecofisiológicos aos 12 meses após o plantio, utilizando 5 plantas selecionadas ao acaso por tratamento. Doze meses após o plantio conclui-se: a leguminosa florestal Mimosa caesalpiniifolia inoculada com fungos micorrízicos Rhizophagus clarus apresentou os melhores resultados em altura, taxa de sobrevivência e eficiência fotossintética. A Acacia mangium sem inoculação com fungos micorrízicos Rhizophagus clarus teve o maior diâmetro e a segunda maior altura. Porém a menor taxa de sobrevivência pode ter superestimado os resultados de diâmetro e altura. DAjuda, DAjuda D Ajuda, Ajuda D’Ajuda x 3x (Acacia Sabiá. Sabiá . (Sabiá) tratamentos FMA planta caule 1 concluise conclui se conclui-se fotossintética (Sabiá

Resumen En este trabajo se evalúa la factibilidad de emplear la arena y arcilla residuales generados por la minería de arena para fabricar bloques de tierra comprimida (BTC) y adobes. Para ello, se caracterizaron los subproductos generados por una mina en la provincia de Río Negro (Argentina) y se confeccionaron diferentes series de probetas, determinando su retracción por secado, densidad seca, resistencia a compresión y resistencia a erosión húmeda. Los resultados indican que, con una dosificación en peso de 74.25% arcilla, 24.75% arena y un 1% de paja, pueden producirse adobes portantes con una resistencia a compresión de 18.63 kgf/cm2, mientras que, empleando una dosificación de 71.3% de arcilla, 23.7% arena y 5% de cemento Portland, pueden producirse BTC con una resistencia a compresión superior a 30 kgf/cm2 y una elevada resistencia a la erosión húmeda, aptos para emplearse en la construcción de muros de carga y muros exteriores sin revoque.

Abstract This work evaluates the feasibility of using residual sand and clay generated by sand mining to manufacture compressed earth blocks (CEB) and adobes. To do this, the byproducts generated by a mine in the province of Río Negro (Argentina) were characterized and different series of samples were made, determining their shrinkage due to drying, dry density, compressive strength and wet erosion resistance. The results indicate that, with a dosage by weight of 74.25% clay, 24.75% sand and 1% wheat straw, load-bearing adobes can be produced with a compressive strength of 18.63 kgf/cm2, while, using a dosage of 71.3% clay, 23.7% sand, 5% Portland cement, CEB can be produced with a compressive strength greater than 30 kgf/cm2 and a high resistance to wet erosion, suitable for use in the construction of load-bearing walls and exterior walls without plaster.

ABSTRACT The peculiar characteristics of mining waste substrates represent a significant challenge for environmental rehabilitation. Here, we evaluated the revegetation potential of Paspalum cinerascens on substrates from mining areas of Serra dos Carajás, a region harboring a large mine complex in the eastern Brazilian Amazon. Paspalum cinerascens is a native grass widely distributed in the canga ecosystem, a vegetation type covering iron ore reserves. Seeds of P. cinerascens harvested in canga were germinated in sterilized quartzite sand and the seedlings grown in controlled conditions for 90 days. The seedlings were then cultivated in canga topsoil (control, without fertilization) and mining waste substrate with half and complete fertilization currently applied at the beginning of mineland rehabilitation in Serra dos Carajás. Regardless of fertilization, plants grown in the mining waste substrate did not differ in carbon assimilation, tillering rate and root biomass, despite higher leaf nutrient content and lower root: shoot ratio when compared to plants in canga topsoil. Compared to the control, complete fertilization led to significantly taller plants, higher shoot biomass and reduced water use efficiency. Half fertilization led to higher phosphorus and water use efficiency and stomatal density. Our results confirmed that P. cinerascens has adaptive traits to grow and thrive in the harsh environmental conditions of post iron ore mining, and can be used in rehabilitation processes. Moreover, half fertilization led to plants with optimized water loss in exchange for carbon without significant costs to plant growth, an interesting trait for rehabilitation in areas experiencing water restrictions. Here Carajás Amazon ecosystem reserves P 9 days control (control assimilation density processes Moreover growth restrictions

RESUMO As características peculiares dos substratos de remanescentes da mineração (estéril de mina) representam um desafio para a recuperação ambiental. Neste estudo avaliamos o potencial de uso de Paspalum cinerascens para revegetação de estéril de mina na Serra dos Carajás, Pará (Brasil). Paspalum cinerascens é uma gramínea nativa amplamente distribuída nas cangas, vegetação típica dos campos rupestres que cobrem reservas de minério de ferro. As plantas de P. cinerascens foram cultivadas em topsoil de canga (controle) e em estéril de mina com meio e completo regime de fertilização atualmente empregado para revegetação das áreas mineradas na Serra dos Carajás. Foram utilizadas sementes coletadas nas cangas e as plantas foram cultivadas em condições controladas por 90 dias. Independentemente da fertilização, plantas cultivadas em estéril de mina não apresentaram diferenças significativas na assimilação de carbono, perfilhamento ou biomassa radicular, apesar de valores mais elevados de nutrientes foliares e menor razão raiz: parte aérea quando comparadas às plantas em topsoil de canga. A fertilização completa resultou em plantas mais altas, maior biomassa aérea e menor eficiência no uso da água. Metade da fertilização aumentou a densidade estomática, a eficiência de uso da água e de fósforo. Esses resultados confirmaram que P. cinerascens possui características adaptativas para crescer e prosperar em condições ambientais adversas remanescentes da mineração, sendo indicada para uso em processos de recuperação de áreas degradadas na Serra dos Carajás. Além disso, o uso de metade do regime de fertilização otimiza o uso da água pelas plantas sem perdas significativas de crescimento, uma característica desejável para recuperação de áreas com restrições hídricas. ambiental Carajás Brasil. Brasil . (Brasil) ferro P controle (controle 9 dias carbono radicular raiz altas estomática fósforo disso crescimento hídricas (Brasil

Resumen La convergencia de la agricultura convencional, las inversiones inmobiliarias y la minería de extracción de arena y grava caracterizan a Calimaya como uno de los municipios del Altiplano mexicano más impactados negativamente por las actividades antrópicas. El objetivo de este trabajo fue analizar el contexto geográfico y ambiental de los procesos de cambio de uso y cobertura del suelo (CUCS) en este Municipio. Para ello, se estimaron los siguientes indicadores: la tasa de cambio de cobertura propuesta por la Organización de las Naciones Unidas para la Alimentación y la Agricultura utilizando las clases de cobertura del suelo propuestas por el Grupo Intergubernamental de Expertos sobre Cambio Climático. Los CUCS encontrados en la última década (2010-2019) fueron: deforestación y avance del cultivo de papa en el Área de Protección de Flora y Fauna Nevado de Toluca; disminución del proceso de ocupación de áreas de cultivo por parte de los asentamientos; y degradación del suelo en minas abandonadas.

Resumo A convergência da agricultura convencional, investimentos imobiliários e mineração de extração de areia e cascalho caracterizam Calimaya como um dos municípios do Altiplano mexicano mais impactados negativamente pelas atividades antrópicas. O objetivo deste trabalho foi analisar o contexto geográfico e ambiental dos processos de mudança de uso e cobertura do solo (MUCS) neste Município. Para isso, foram estimados os seguintes indicadores: a taxa de mudança de cobertura proposta pela Organização das Nações Unidas para Agricultura e Alimentação utilizando as classes de cobertura do solo propostas pelo Painel Intergovernamental sobre Mudanças Climáticas. Os MUCS encontrados na última década (2010-2019) foram: desmatamento e avanço do cultivo de batata na Área de Proteção de Flora e Fauna Nevado de Toluca; diminuição do processo de ocupação das áreas cultivadas pelos assentamentos; e degradação do solo em minas abandonadas.

Abstract The convergence of conventional agriculture, real estate investments and sand and gravel mining characterize Calimaya as one of the most negatively impacted municipalities of the Mexican altiplano by anthropic activities. The objective of this work was to analyse the geographical and environmental context of land use and land cover change (LULCC) processes in this Municipality. For this, the following indicators were estimated: the cover change rate proposed by Food and Agriculture Organization of the United Nations by using the land cover classes proposed by the Intergovernmental Panel on Climate Change. LULCC in the last decade (2010-2019) were: deforestation and advancement of potato crop in the Nevado de Toluca Flora and Fauna Protection Area; decrease in the process of occupation of cropland areas by settlements; and, soil degradation in abandoned mines.

Abstract Introduction: The study estimated the prevalence rate of Acute Respiratory Diseases and Symptoms (ESRA) and its risk factors (RF), it was carried out in three host neighborhoods: Salsipuedes (200 households), San Miguel (35) and Ampliación San Miguel (9) from the southeast region of the city of San Cristóbal de Las Casas, Chiapas, Mexico, where the Salsipuedes stone mining company of sand and gravel for construction of roads and houses is located, for 35 years of extraction. Methodology: A cross-sectional epidemiological study was carried out, it began with a population census, where the survey was accepted in 156 (63.9 % of the total) and a structured questionnaire with closed and open questions was applied to an adult of each family. The questions were oriented to identify the signs and symptoms of incident and prevalent diseases (closed questions), on the other hand, six open qualitative questions related to how do you consider the activity of the sandbank that exists in your neighborhood?, to identify the perceptions of the risk for social, environmental and health damages, and whether or not they associated them with living in those neighboring host neighborhoods of the mining company. Results: The prevalence rate of ESRA in Salsipuedes was 5.6%, San Miguel 12.0% and Ampliación San Miguel 21.9% (total TP=7.6%) (p ≤ 0.05); Nine socioeconomic variables were explored, of which five (wooden wall of the house, proximity to the neighborhood, proximity to the international highway, home ownership and health perception) were statistically associated with stone mining activity with a significance value statistic of (p ≤ 0.05). Conclusion: Mining activities had an impact on ESRA associated with the proximity and conditions of housing and also influenced negative perceptions of health and the environment.

Resumen Introducción: el estudio estimó la tasa de prevalencia de enfermedades y síntomas respiratorios agudos (ESRA) y sus factores de riesgo (FR). Se llevó a cabo en tres colonias anfitrionas: Salsipuedes (200 viviendas), San Miguel (35) y Ampliación San Miguel (9) de la región sureste de la Ciudad de San Cristóbal de Las Casas, Chiapas, México, donde se ubica la minera pétrea de arena y grava para construcción de carreteras y viviendas, desde hace 35 años. Metodología: se realizó un estudio transversal epidemiológico; se inició con un censo de población y 156 hogares (el 63.9 % del total) aceptaron participar en la encuesta, así, se aplicó un cuestionario estructurado con preguntas cerradas y abiertas a un mayor de edad de cada familia. Por un lado, las preguntas cerradas se orientaron a identificar los signos y los síntomas de enfermedades incidentes y prevalentes; por otro lado, se hicieron seis preguntas abiertas cualitativas relacionadas con cómo se considera la actividad del banco de arena existente en cada barrio, a fin de conocer las percepciones del riesgo social, ambiental y de salud, y su posible asociación con habitar en colonias limítrofes con la minera. Resultados: la tasa de prevalencia de ESRA en Salsipuedes fue del 5.6 %, en San Miguel del 12.0 % y en Ampliación San Miguel del 21.9 % (TP total=7.6 %) (p ≤ 0.05). Se exploraron nueve variables socioeconómicas, de ellas, cinco (pared de madera de la vivienda, proximidad de la colonia, proximidad de la carretera internacional, tenencia del hogar y percepción de salud) se asociaron estadísticamente con la actividad minera pétrea con un valor de significancia estadística de p ≤ 0.05. Conclusiones: las actividades de minería repercuten en las ESRA y se vinculan a la proximidad y las condiciones de la vivienda, asimismo, influyen en las percepciones negativas de la salud y el ambiente.

ABSTRACT Large-scale mining operations, such as those associated with iron extraction, disturb soils and vegetation and create the need for effective rehabilitation practices. The Iron Quadrangle region of southeastern Brazil is one of the world’s biodiversity hotspots; however, iron mining activities threaten many natural and seminatural ecosystem types in which many rare/protected species occur. The Iron Quadrangle has four main ecosystem types: Atlantic Forest (AF), ferruginous rupestrian grassland with dense vegetation (FRG-D); ferruginous rupestrian grassland with sparse vegetation (FRG-S); and quartzite rupestrian grassland (QRG). To support rehabilitation and monitoring plans, we evaluated reference areas and identified soil and vegetative attributes that best differentiated between these four ecosystems. We measured thirty-four physical, chemical, and biological soil properties and two vegetation parameters and, using a multivariate analysis, detected: 1) correlations between properties and 2) differences between areas. We identified twelve properties that best differentiated the areas (in order from most to least relevant): nickel content; exchangeable aluminum; clay content; above-ground vegetation volume; aluminum saturation; particle density; bulk density; arsenic content; zinc content; lead content, fine sand plus silt content; and fine sand content. Soil physicochemical properties proved to be more sensitive to differences in ecosystem type, and in particular, parameters related to fertility and the presence of metals and semi-metals differentiated the AF from the FRG-D and FRG-S. Soil physical properties, including fine sand and silt content, were most important for differentiating QRG from the other ecosystems, possibly resulting from the exposure of quartzite material to erosive processes. This study demonstrates the importance of identifying appropriate reference areas for post-mining reclamation. Largescale Large scale operations extraction practices worlds world s hotspots however rareprotected rare protected occur AF, , (AF) FRGD FRG D (FRG-D) FRGS S (FRG-S) QRG. . (QRG) plans ecosystems thirtyfour thirty chemical analysis detected 1 2 relevant relevant) content aboveground above ground volume saturation density type particular semimetals semi FRGS. S. FRG-S processes postmining post reclamation (AF (FRG-D (FRG-S (QRG

Resumen La minería informal supone un riesgo para la salud de los ecosistemas. Con el objetivo de restaurar las zonas afectadas por este tipo de actividad de una forma sostenible, se realizó un ensayo en microcosmos durante ocho meses con Enterolobium cyclocarpum, (Jacq.) Griseb. 1960, inoculadas con microorganismos promotores del crecimiento en arenas de relave procedentes de minería informal. Este estudio se hizo dentro de un invernadero ubicado en el municipio de Buriticá del departamento de Antioquia (dentro de los predios de Zijin - Continental Gold). La especie vegetal fue plantada en macetas de 10 L, conteniendo aproximadamente 14 kg de arenas de relave (A) o arenas de relave mezclada con materia orgánica [5% p/p de gallinaza compostada (A+MO)]. Se ensayó el efecto de microorganismos comerciales. En cada maceta se añadieron Micorrizas (0 g ó 50 g Mycorfos®), ó Rizobium (0 cm3 ó 0,5 cm3 de Rhizobiol® ó la mezcla de los 2 en las mismas dosis. En total hubo 24 macetas. A pesar de los altos niveles de elementos traza (ET) totales en las arenas de relave (As 269 mg/kg; Cd 461 mg/kg), el Enterolobium cyclocarpum se adaptó a las condiciones de los sustratos, presentando en el tratamiento de arena con micorrizas, la mayor concentración de As y Cd acumulado en las partes aéreas de las plantas. Por su parte, en los tratamientos sin enmienda orgánica que llevaban incorporados hongos micorrícicos, A+M y A+FN+M, la mayor concentración de As y Cd se presentó en la raíz.

Abstract Informal mining poses a risk to ecosystem health. With the aim of restoring the areas affected by this type of activity in a sustainable way, a microcosm trial was carried out for eight months with Enterolobium cyclocarpum, (Jacq.) Griseb. 1960, inoculated with growth-promoting microorganisms in tailings sands from informal mining. This study was carried out in a greenhouse located in the municipality of Buriticá in the department of Antioquia (on the premises of Zijin - Continental Gold). The plant species were planted in 10 L pots, containing approximately 14 kg of tailings sand (A) or tailings sand mixed with organic matter [5% w/w composted poultry manure (A+MO)]. The effect of commercial micro-organisms was tested. Mycorrhizae (0 g or 50 g Mycorfos®), or Rhizobium (0 cm3 or 0.5 cm3 of Rhizobiol® or a mixture of the two at the same doses were added to each pot. In total there were 24 pots. Despite the high levels of total trace elements in the tailings sand (As 269 mg/kg; Cd 461 mg/kg), Enterolobium cyclocarpum adapted to the substrate conditions, with the highest concentration of As and Cd accumulated in the aerial parts of the plants in the mycorrhizal sand treatment. On the other hand, in the treatments without organic amendment that incorporated mycorrhizal fungi, A+M and A+FN+M, the highest concentrations of As and Cd were found in the roots.

Abstract The Magnetic separation of ultra-fine ore particles has always posed a challenge to the JONES/WHIMS process. Despite many advances in this technology, no effective improvement has been made to its core component: The Magnetic Matrix. The current approach to separate ultra-fine particles teaches that the gap of the matrix and its teeth size must be smaller than usual in order to accommodate the small size of the particles. However, practice proved this approach to be far from ideal. The closing of the gap between grooved plates, whose teeth are smaller, drastically reduces the flow area, reduces the feed capacity, and makes the matrices prone to clogging. In addition, smaller teeth reduce the magnetic field and its gradient, leading to poor results with ultra-fine ore particles. This research proves that bigger teeth are better suited for high intensity magnetic separation of ultra-fines because they avoid matrix clogging thanks to the larger slurry flow area. Additionally, bigger teeth amplify the magnetic field “Bmax” and increases the magnetic gradient “Grad (∆B /∆X)”. The positive results of this new “BigFLUX Matrix” technology, are being displayed in several mining operations worldwide, increasing metallurgical recovery and producing high quality concentrates and low iron content sand from iron ore tailings.

Abstract In recent past years, plastic waste has been a environmental menace. Utilization of plastic waste as fine aggregate substitution could reduce the demand and negative impacts of sand mining while addressing waste plastic challenges. This study aims at evaluating compressive strengths prediction models for concrete with plastic-mainly recycled plastic-as partial replacement or addition of fine aggregates, by use of artificial neural networks (ANNs), developed in OCTAVE 5.2.0 and datasets from reviews. 44 datasets from 8 different sources were used, that included four input variables namely: -water: binder ratio; control compressive strength (Mpa); % plastic replacement or additive by weight and plastic type; and the output variable was the compressive strength of concrete with partial plastic aggregates. Various models were run and the selected model, with 14 nodes in hidden layer and 320,000 iterations, indicated overall root mean square error (RMSE) , absolute factor of variance (R2), mean absolute error (MAE) and mean absolute percentage error (MAPE) values of 1.786 MPa, 0.997, 1.329 MPa and 4.44 %. Both experimental and predicted values showed a generally increasing % reduction of compressive strengths with increasing % plastic fine aggregate. The model showed reasonably low errors, reasonable accuracy and good generalization. ANN model could be used extensively in modeling of green concrete, with partial waste plastic fine aggregate. The study recommends ANNs models application as possible alternative for green concrete trial mix design. Sustainable techniques such as low-cost superplasticizers from recycled material and cost-effective technologies to adequately sizing and shaping plastic for fine aggregate application should be encouraged, so as to enhance strength of concrete with partial plastic aggregates.

Resumen En los últimos años, los desechos plásticos han sido una amenaza para el medio ambiente. La utilización de desechos plásticos como sustitución de agregados finos podría reducir la demanda y los impactos negativos de la extracción de arena al tiempo que aborda los desafíos de los desechos plásticos. Este estudio tiene como objetivo evaluar modelos de predicción de resistencias a la compresión para concreto con plástico, principalmente plástico reciclado, como reemplazo parcial o adición de agregados finos, mediante el uso de redes neuronales artificiales (ANN), desarrollado en OCTAVE 5.2.0 y conjuntos de datos de revisiones. Se utilizaron 44 conjuntos de datos de 8 fuentes diferentes, que incluían cuatro variables de entrada, a saber: - relación agua: aglutinante; controlar la resistencia a la compresión (Mpa); % de reemplazo o aditivo de plástico por peso y tipo de plástico; y la variable de salida fue la resistencia a la compresión del hormigón con agregados plásticos parciales. Se ejecutaron varios modelos y el modelo seleccionado, con 14 nodos en la capa oculta y 320.000 iteraciones, indicó el error cuadrático medio general (RMSE), el factor de varianza absoluto (R2), el error absoluto medio (MAE) y el error porcentual absoluto medio (MAPE). ) valores de 1,786 MPa, 0,997, 1,329 MPa y 4,44%. Tanto los valores experimentales como los predichos mostraron un% de reducción generalmente creciente de las resistencias a la compresión con el aumento del% de agregado fino plástico. El modelo mostró errores razonablemente bajos, precisión razonable y buena generalización. El modelo ANN podría utilizarse ampliamente en el modelado de hormigón verde, con áridos finos de plástico de desecho parcial. El estudio recomienda la aplicación de modelos ANNs como posible alternativa para el diseño de mezclas de prueba de concreto verde. Deben fomentarse las técnicas sostenibles, como los superplastificantes de bajo costo a partir de material reciclado y las tecnologías rentables para dimensionar y dar forma adecuada al plástico para la aplicación de agregados finos, a fin de mejorar la resistencia del hormigón con agregados plásticos parciales.

Resumo Introdução. A indústria cimenteira é uma das causas das mudanças climáticas, por isso a pesquisa está focada no uso de materiais residuais que podem reduzir a quantidade de matéria-prima extraída para a fabricação. Além disso, é necessário avaliar os danos ambientais associados a esses novos produtos que garantem a redução de efeitos negativos. Objetivo. Esta pesquisa tem como objetivo avaliar os impactos ambientais, utilizando a análise do ciclo de vida (ACV) com base na ISO 14040, causada por uma cadeia produtiva de cimento portland com uma substituição de 14 % de casca de ovo e 5 % de casca de arroz, mantendo processos atuais como moagem e incineração com o mesmo consumo de energia. Materiais e Métodos: Para o análise do inventário, foi levado em conta ao banco de dados Agribalyse v3.0.1, que é um banco de dados, um repositório francês para análise da LCA no setor agrícola e alimentício, estes estão imersos no software a ser utilizado, como o OpenLCA. Para este cimento com percentual de substituição de casca de ovo (14 %) e casca de arroz (5 %) é necessário: Casca de ovo e casca de arroz. Insumos energéticos de sistemas externos, como carvão e eletricidade. Calcário, Areia e Gesso. Transporte de materiais e ambos geram como saídas um cimento Portland com substituição de 14 % ch e 5 % AC (para 1 tonelada de cimento). Resultados. Observa-se que a indústria com maior contribuição para as mudanças climáticas está relacionada à produção de energia sob a forma de combustão, que fornece um total de 398,10 kg de CO2 equivalente para cada tonelada de cimento com substituição de 14 % de CH e 5 % de AC, esse processo está relacionado durante a fase de produção em processos de incineração. Da mesma forma, a segunda indústria com maior contribuição para as mudanças climáticas é a indústria mineira, responsável pela liberação de 200,10 kg de CO2 equivalente a cada tonelada desse tipo de cimento. Conclusões. Este estudo constatou que o uso de substituição de 14 % de AC ch e 5 % em um cimento Portland e sua incorporação no processo atual implica uma diminuição em todos os impactos ambientais associados. Uma vez que, apesar dos novos efeitos associados à produção de arroz, esses estarão sempre presentes por ser um produto alimentício de grande necessidade que gera muito desperdício por não fornecer adequadamente sua casca, por isso adicioná-la junto com outros resíduos, como cascas de ovos, implica uma melhoria voltada para a economia circular.

Resumen Introducción. La industria cementera es una de las causantes del cambio climático, por lo que las investigaciones actualmente están enfocadas en utilizar materiales de desecho que puedan reducir la cantidad de materia prima que se extraiga para su fabricación. Así como también es necesario evaluar los daños ambientales asociados a estos nuevos productos que garanticen la reducción de los efectos negativos. Objetivo. Evaluar los impactos ambientales, utilizando el análisis del ciclo de vida (ACV) basado en la norma ISO 14040, ocasionados por una cadena de producción de cemento Portland con un reemplazo de 14 % de cáscara de huevo y 5 % de cáscara de arroz, manteniendo los procesos actuales como molienda e incineración con el mismo consumo energético. Materiales y métodos. Para el análisis del inventario se tuvo en cuenta la base de datos de Agribalyse v3.0.1, la cual es un un repositorio francés para el análisis de ACV del sector agrícola y alimentario, estas inmersas en el software a usar como es OpenLCA. Para esto el cemento con porcentaje de reemplazo de cáscara de huevo (14 %) y cascarilla de arroz (5 %) se requiere: Cáscara de huevo y cascarilla de arroz. Insumos energéticos de sistemas externos como el carbón y la electricidad. Piedra Caliza, Arena y Yeso. Transporte de materiales Y generan ambos como salidas un cemento Portland con reemplazo de 14 % de CH y 5 % de CA (para 1 tonelada de cemento). Resultados. Es posible observar que la industria con mayor aporte al cambio climático es la relacionada con la producción de energía en forma de combustión, la cual aporta un total de 398,10 kg de CO2 equivalente por cada tonelada de cemento con reemplazo de 14 % de CH y 5 % de CA, este proceso es relacionado durante la etapa de producción en los procesos de incineración. Así mismo, la segunda industria con más aporte al cambio climático es la industria minera, la cual es responsable de la liberación 200,10 kg de CO2 equivalente por cada tonelada de este tipo de cemento. Conclusiones. Mediante este estudio se pudo constatar que el uso de reemplazo de 14 % de CH y 5 % de CA en un cemento Portland y su incorporación en el proceso actual, implica una disminución en todos los impactos ambientales asociados. Ya que, a pesar de se generen nuevos efectos asociados a la producción del arroz, estos siempre estarán presentes debido a que es un producto alimentario de primera necesidad que genera gran cantidad de residuos al no disponer adecuada su cáscara, por lo que adicionarla junto a otro desecho como las cáscaras de huevo implica una mejora encaminada a la economía circular.

Abstract Introduction. The cement industry is one of the causes of climate change, so research is currently focused on using waste materials that can reduce the amount of raw material that is extracted for manufacturing. As well as it is necessary to evaluate the environmental damage associated with these new products that guarantee in reducing negative effects. Objective. evaluate environmental impacts, using life cycle analysis (LCA) based on ISO 14040, caused by a Portland cement production chain with a replacement of 14 % eggshell and 5 % rice husk, maintaining current processes such as grinding and incineration with the same energy consumption. Materials and methods. For inventory analysis, account was taken of Agribalyse database v3.0.1, which is the French repository for the analysis of ACV in the agricultural and food sector, these are immersed in the software to be used, which is OpenLCA. For this the cement with percentage of replacement of eggshell (14 %) and rice husk (5 %) is required: Eggshell and rice husk. Energy inputs from external systems such as coal and electricity. Limestone, Sand and Gypsum. Transport of materials And they both generate as outputs a Portland cement with replacement of 14 % ESP and 5 % RH (for 1 ton of cement). Results. It can be observed that the industry with the greatest contribution to climate change is related to energy production in the form of combustion, which provides a total of 398.10 kg of CO2 equivalent for each ton of cement with replacement of 14 % CH and 5 % AC, this process is related during the production stage in incineration processes. Similarly, the second industry with the most contribution to climate change is the mining industry, which is responsible for the release of 200.10 kg of CO2 equivalent for each ton of this type of cement. Conclusions. This study found that the use of replacement of 14 % ESP and 5 % RH in a Portland cement and its incorporation into the current process implies a decrease in all associated environmental impacts. Since, despite new effects associated with rice production, these will always be present because it is a food product of great need that generates a lot of waste by not adequately providing its shell, so adding it together with another waste such as eggshells implies an improvement aimed at the circular economy.

RESUMEN El constante desarrollo minero ha generado una gran cantidad de pasivos ambientales, especialmente relaves mineros (residuos mineros), almacenados en relaveras, la mayoría de los cuales son abandonados después de su vida útil, sin mantener un control químico y físico, generando contaminación ambiental. El desarrollo de adoquines empleando los relaves de mina empieza con los análisis: físicos, mineralógicos y químicos de las arenas de relave, para determinar si el material es apto como agregado. Una vez analizado el relave, se realizó prototipos de adoquines usando diferentes dosificaciones reemplazando el polvo de piedra con el relave y así determinar las mejores características de resistencia física apegados a la normativa INEN 3040 e INEN 1488 1986. Se determinó que la dosificación adecuada como agregado de relave es reemplazando en un 70% al polvo de piedra en la fabricación de adoquines. Se concluye que mortero diseñado en base a arena de relave, cemento y agregados representa un ahorro al momento de gestionar estos residuos en relación a la construcción de nuevas relaveras. Se obtuvo una resistencia a la tracción de 3MPa, cuyo valor se encuentra ligado al alto contenido de cuarzo (±80%), propio de la paragénesis mineral del yacimiento

ABSTRACT The constant mining development has generated a large number of environmental liabilities, especially mine tailings (mining waste), stored in tailings, most of which are abandoned after their useful life, without maintaining chemical and physical control, generating environmental contamination. The development of pavers using mine tailings begins with the physical, mineralogical and chemical analyzes of the tailings sand, to determine if the material is suitable as an aggregate. Once the tailings were analyzed, prototypes of pavers were made using different dosages, replacing the stone powder with the tailings in order to determine the best physical resistance characteristics according to INEN 3040 and INEN 1488 1986 standards. It was determined that the adequate dosage as tailings aggregate is replacing 70% of the stone dust in the manufacture of pavers. It is concluded that mortar designed based on tailings sand, cement and aggregates represents a saving at the time of managing these residues in relation to the construction of new tailings. A tensile strength of 3MPa was obtained, whose value is linked to the high quartz content (±80%), typical of the mineral paragenesis of the deposit