Search

This paper summarizes the findings of several years of the authors' research on copper phytotoxicity in soils contaminated by copper mining industry in the Valparaiso region of central Chile. Although soils under study were contaminated by several elements, copper was found to be the most important factor limiting plant growth, while the other elements had no statistically significant effect. The concentration of copper in the 0.1 M KNO3 extract proved to be the best indicator of phytotoxicity compared to the total copper content or the activity of free Cu2+ ions in the same extract. The total copper content, pH, and dissolved organic carbon concentration were in turn found to be the most important variables in predicting copper concentration and copper ion activity in the 0.1 M KNO3 extract. [ABSTRACT FROM AUTHOR]

Copper mining activity is going through big changes due to increasing technological development in the area and the influence of industry 4.0. These changes, produced by technological context and more controls (e.g., environmental controls), are also becoming visible in Chilean mining. New regulations from the Chilean government and changes in the copper mining industry (such as a trend to underground mining) are fostering the search for better results in typical processes such as leaching. This paper describes an experience using artificial intelligence techniques, particularly random forest, to develop predictive models for copper recovery by leaching, using data from an enterprise present in northern Chile for more than 20 years. Two models, one of them with actual operational data and another one with data generated in a controlled environment (piling) are presented. Well-classified values of 98.90% for operational data and 98.72% for pile/piling data were obtained. The methodology devised for the study can be transferred to piling columns or piles with other characteristics, though the operation must focus on copper leaching. It can even be transferred to other leaching processes using another type of mineral, with proper adjustments. [ABSTRACT FROM AUTHOR]

Nowadays, many major copper mining projects in desert areas with extremely dry climates, as in northern Chile and the southern coast of Peru, process sulfide ores at high production rates; in some cases over 100,000 metric tonnes per day (mtpd), generating large amounts of tailings, that are commonly managed and transported to tailings storage facilities (TSF) hydraulically using fresh water. Considering the extremely dry climate, water scarcity, community demands, and environmental constraints in these desert areas, the efficient use of water in mining is being strongly enforced. For this reason, water supply is recognized as one of the limiting factors for the development of new mining projects and for the expansion of the existing ones in these areas. New water supply alternatives, such as sea water desalinization, direct use of sea water, or water recovery from tailings, represent the strategy developed by the mining industry to deal with this growing scarcity. The focus of this paper is the possibility of applying different water supply technologies or a combination of these, implementing improved water management strategies that consider: environmental issues, technical issues, stringent regulatory frameworks, community requests and cost-effective strategies, that result in a reduction of freshwater make-up water requirements for mining (m3 per metric tonnes of treated ore). [ABSTRACT FROM AUTHOR]

In Tocopilla, a port in northern Chile, a thermoelectric plant was installed to supply with electricity the Chuquicamata mine, the world's largest copper mine during most of the twentieth century. In a context of strikes and socioeconomic demands against labour exploitation and work precariousness, the American owners of Chuquicamata took advantage of an anti-communist law to prevent workers' organizations and their claims. Moreover, the workers who were labelled as 'communists' were also labelled as 'Indians' in the context of mining colonialism. The paper examines the historical process of construction of 'race' in a political situation that had a profound impact on the lives of Chilean workers in the Atacama Desert. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a thermal power plant retrofitting approach focused on improvements in the operational flexibility of existing combined cycle power plants dedicated to providing thermal energy for medium and low‐temperature processes in copper mining facilities. The main motivation for this research was aimed at evaluating the operational flexibility of the electrical industry through sector coupling and its effect on solving the energy sector decarbonization issues. The research evaluates the advantages of hybridization systems for supporting the electrical and mining industries to better predict operations. The proposed approach is based on a dynamic simulation scheme that finds the optimal operating parameters of the combined heat and power (CHP) system, such as location, type, and arrangement of each component of the CHP system. The power plant dynamic simulation model was validated against data available in the literature; it was also characterized by real operational data of the San Isidro II power plant installed in Chile. Several alternatives for the cogeneration plant location, as well as the splitter system design, were investigated and then compared. A cogeneration plant design with two heating modules was selected based on the comparative study performed in this work and its CHP system was evaluated for a load reduction case study. The results were compared against a reference model. The proposed CHP system exhibited improved performance: a minimum of 15% of the exhaust gases are required to supply the thermal energy demand of the electrowinning process when a full load is considered. It was also found that an average decrease of 5% of the mechanical power at each steam turbine stage noted. Finally, the proposed CHP system's average thermodynamic efficiency is found to be 19% greater than the power plant average efficiency. Consequently, an average decrease of 32 500 tons of carbon dioxide emissions per year is predicted. [ABSTRACT FROM AUTHOR]

The El Teniente Mine of Codelco is one of the largest underground mine operations in the world. The mine employs massive mechanised panel caving methods with pre-undercut variants to extract copper-molybdenum ore, producing 140,000 t/d, mainly of primary copper ore. In the context of a study of rehabilitation measures for collapsed zones at the Esmeralda mine, which is one of Tenientés most important operations, a preliminary assessment of the post-collapse pillar's rock mass condition was carried out, allowing the characterization of the damage zone surrounding the drifts and some insights into the likely pillar's rock mass damage development. The paper outlines these findings and discusses some underlying factors that may also have influenced the process. [ABSTRACT FROM AUTHOR]

Purpose--The purpose of this paper is to provide an overview of recent developments in employment relations in Chile, focusing on recent episodes of contract labour mobilisation in the forestry and copper mining sectors. Design/methodology/approach -- This paper is based on a consolidation of existing evidence from a range of primary, secondary and tertiary, sources. Findings -- The paper demonstrates the inadequacy of Chile's employment relations institutions to protect vulnerable workers and shows the capacity of contract workers to overcome such limitations by recurring to mobilisation. It argues that contract labour mobilisation rather than a shift left in government seems to offer a more plausible explanation of current developments in Chilean employment relations. Research limitations/implications -- The paper identifies salient issues but further research is necessary to understand the actual social processes of collective action involved in recent episodes of contract labour mobilisation. Practical implications- This information could contribute to better policy making, better management of the employment relationship, and informing the revitalisation of labour movements. Originality/value- There are few studies on contract workers' collective action particularly in developing countries, and a contribution is made to critical debates on the sustainability of Chile's neoliberal socio-economic and employment relations system. [ABSTRACT FROM AUTHOR]

Fungi are ubiquitous and metabolically versatile. Their dispersion has important scientific, environmental, health, and economic implications. They can be dispersed through the air by the aerosolization of near surfaces or transported from distant sources. Here, we tested the contribution of local (scale of meters) versus regional (kilometers) sources by analyzing an airborne fungal community by ITS sequencing around a copper mine in the North of Chile. The mine was the regional source, whereas the soil and vegetal detritus were the local sources at each point. The airborne community was highly homogeneous at ca. 2000 km2, impeding the detection of regional or local contributions. Ascomycota was the dominant phylum in the three communities. Soil and vegetal detritus communities had lower alpha diversity, but some taxa had abundance patterns related to the distance from the mine and altitude. On the contrary, the air was compositionally even and unrelated to environmental or spatial factors, except for altitude. The presence of plant pathogens in the air suggests that other distant sources contribute to this region's airborne fungal community and reinforces the complexity of tracking the sources of air microbial communities in a real world where several natural and human activities coexist. [ABSTRACT FROM AUTHOR]

Recordings of earthquakes by a temporary deployment of 84 short period seismometers in northern Chile were used to derive regional 3D seismic velocity models for the Taltal segment. We used the Regressive ESTimator (REST) package for event detection and automatic onset estimation of P‐ and S‐wave arrival times to create an earthquake catalog with 23,985 hypocenters. We followed standard acceptability criteria (i.e., azimuthal gap and residual cutoff) to create a high‐quality data set and inverted for 3D Vp, Vs and Vp/Vs models using local earthquake tomography. Plots of hypocenters from the catalog, comprising 16,349 earthquakes, reveal active structures in the upper crust, dip changes along the slab and fracturing within the oceanic crust. Moreover, the wavespeed models illuminate anomalies in both the Nazca and South American plates that correlate with the observed seismicity distribution, including variations from low (1.75) to high (>1.80) Vp/Vs near the Atacama fault system on the coastline and the Domeyko Fault System in the forearc. The seismic velocity models also provide evidence for fluid circulation caused by the subducting Taltal ridge on the coast and partial melting feeding a volcanic complex close to the Andes. Finally, the observed low Vp/Vs ratios (∼1.75) are associated with copper mining operations in the area, suggesting that this kind of imaging can be used to characterize the distribution of potential ore deposits in the area. Plain Language Summary: We recorded earthquakes in northern Chile with a network of 84 seismometers and used the arrival times of P and S waves to generate 3D wavespeed models of the region. These models reveal several structures in the area, including changes in the angle of the subducting Nazca plate and fractures in the oceanic crust. Among features observed in both the Nazca and South American plates are the Atacama and Domeyko fault systems. We also infer fluid circulation caused by the subducting Taltal ridge and partial melting that feeds a volcanic complex near the Andes. Low values of the Vp/Vs ratio are associated with copper mining operations in the area and could be used to identify new ore deposits. Key Points: Seismic catalog reveals forearc activity and slab dip variations. Vp anomalies in the oceanic plate are related to mid‐depth seismic eventsVelocity models uncover anomalies in Salar de Atacama and Taltal ridge that might influence seismicity distribution and hydration changesShallow low Vp/Vs (<1.75) correlate with ore deposits; deep high Vp/Vs (>1.80) suggest fluids and melting for the Lastarria volcanic complex [ABSTRACT FROM AUTHOR]

Decreases in the copper grade, waste disposal, energy supply, and water scarcity are some of the most critical challenges for the copper mining industries. One of the alternatives to counteract the water scarcity is the use of seawater, whether raw, partially desalinated, or desalinated. The use of seawater implies the generation of several compounds as a result of the interaction of ions in waters and ores. For this reason, it is required a greater understanding of these compounds generated on mineral processing, being Pourbaix diagrams used to estimate the possible compounds that will be formed in an aqueous medium for a given metal ore. In this paper, the effect of temperature, salinity, and Cu-concentration on the stability of the copper-solid species was investigated by constructing Pourbaix diagrams for different copper ore types with seawater. The results show that the corrosion areas decrease when the temperature increases for both oxidized and sulfide minerals. It was confirmed that the concentration is a critical variable that influences the size of corrosion areas. In terms of the effect of the other ions that seawater contains, carbonate, chloride, and bromide affect the stability of the Cu-solid species. The proposed diagrams serve as a useful tool to predict the stable species that may be obtained when seawater is used. The use of seawater in mining is an essential issue because it is considered as a more sustainable alternative instead of use freshwater or desalinated seawater, especially in locations with complex water availability, as is northern Chile. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mine operations in the future will require automatic rock characterization at many different stages, since it can be used to supervise and optimize various processes in the laboratory as well as at the mine locations for planning and exploitation. Different methods for classifying rocks based on image analysis have been proposed in the past. In this paper, we report the use of hyperspectral sensors in the classification of rock lithology. The lithology provides information about the chemical composition of the rock, and its physical properties. According to our literature review, this is the first time hyperspectral sensors have been employed in rock type classification. Additionally, it is the first time the use of three different technologies in rock type classification has been reported: hyperspectral sensors, laser range and a color camera. We use two hyperspectral sensors, one has sensibility within the visible and near-infrared range of 400–1000 nm, and the second has sensibility within the short-wavelength infrared range of 900–2500 nm. The range and high definition color images are used to perform accurate segmentation of the rock samples. Images are tessellated into sub-images in which various features from the three sensor types are extracted. In a first stage, the sub-images are classified by using a support-vector machine (SVM) classifier with the extracted features as inputs. In a second stage, the rock segmentation is used to perform a voting process among all the sub-images of each rock and improve the classification. The method was tested using a database with 13 lithologies from a copper mine in Chile. The results show that lithological classification performance obtained by using hyperspectral images greatly exceeds the performance of the color and range images. The achieved classification performance was 98.62% using sub-image classification and 99.95% using a voting process among sub-images. The number of features was also reduced by using the CMIM (Conditional Mutual Information Maximization) feature selection method, achieving a performance of over 99% with using only 3% of the total number of features. • High performance rock type classification is reached using hyperspectral images. • A classification performance of 99.95% is obtained with 13 different rock types. • Performance of over 99% is obtained by selecting only 3% of the features. • Classification by sub-images improved by a voting process inside each rock. [ABSTRACT FROM AUTHOR]

Copyright of Etnográfica: Revista do Centro de Estudos de Antropologia Social is the property of Centro em Rede de Investigacao em Antropologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: A study of deep penetrating geochemistry—the surface exploration techniques for finding concealed mineral deposits—was carried out over the Spence porphyry copper deposit in Chile by Australian, Canadian and Chinese laboratories using selective weak leach methods and is briefly reviewed here. Erratic and weak copper anomalies were obtained above the Spence deposit, which is concealed below a thick piedmont gravel cover. In the literature, such patterns are common in most of the weak selective leach studies carried out over known buried deposits. During exploration in unknown area, such weak leach techniques lead to some success and many dry holes. In this paper, stronger selective leaching methods are developed for oxides and sulfides, which may be the stable end products transformed and accumulated by a mobile precursor phase carried upward through the overburden by gas or water through long spans of geological time. The data obtained by the methods developed in this paper produced more significant and consistent anomalous data than previous efforts. Consequently, the leach approaches described here may increase the effectiveness of deep penetrating geochemistry in exploration for concealed ore deposits. [Copyright &y& Elsevier]

This paper analyses the importance and environmental impacts of metallic small-scale mining in Chile. This sector is characterized by the exploitation of primarily artisanal copper (Cu), gold (Au), and silver (Ag) deposits, which are dispersed throughout (Chilean) Regions I through VI, with heaviest concentrations in Regions III and IV. In 2000, Chilean small-scale mines employed some 1700 workers (5.1% of total mining workers), and plants with a production capacity of less than 50 tpd accounted for 0.97% (44,603 t) of Cu; 6.5% (3,484) of Au; and 1.1% (13,665 kg) of Ag output in the country. High-grade ore extraction, flotation, gravity concentration, acid leaching–cementation, and mercury amalgamation, are the main metallurgical technologies employed. Following an overview of Chilean small-scale mining, the paper examines the environmental impacts of its production processes, and discusses the legal support and regulatory framework in place for operations. [Copyright &y& Elsevier]

Abundant evidence suggests that the massive global exploitation of copper mines over the last two decades led to mine aging expressed as ore grade reduction, deepening of open pits and underground operations, hardening of the rock, and increasing stripping ratios. These processes have affected the evolution and change of key environmental footprint indicators. Copper ore grade decline seems the most important of these factors and depends on variables including the rate of extraction, ore deposit geological features, introduction of new technologies, the copper price and its co-products, and the discovery and exploitation of new ore deposits. From 2001 to 2015 Chile increased its copper production by 22% and produced overall 80 million tons of copper, more than it produced in the entire 20th century. This paper explores the effects of mine aging on three key environmental footprint indicators: energy and water consumption, and greenhouse gas emissions. Electric energy consumption per ton of copper should grow in the coming decade at a significantly slower rate than in the last fifteen years because of the slowdown of the ore grade decline in mill concentrators. Additionally, a steeper decrease is expected for the emission of greenhouse gases per ton of copper. [ABSTRACT FROM AUTHOR]

Chile represents almost one third of the world’s copper production. Mining is one of the main industries that contributes to our country’s development with resources and is globally recognized. Due to the end of the commodity cycle, improving productivity will be a key variable in mining performance in incoming years. This paper studies mining productivity in Chile by relying on two indicators: measure of the total factor productivity (TFP) using the traditional Solow methodology, and labor productivity. Since 2000, we found a decrease in TFP, explained mainly by the participation of capital as well as diverse factor adjustments to labor and capital inputs. Average labor productivity also decreases 42% from 1999 to 2010, a decrease explained by four determinants: real mining wages, electricity prices, copper prices and mineral grade. Since 2010, average labor productivity has increased 30%, and there is also an opportunity for additional improvement by reducing energy costs as well as by aligning productivity and labor performances. [ABSTRACT FROM AUTHOR]

Large-scale copper mining has been the main industry in Chile and the countries conforming the Central African Copperbelt for about one century. While a relatively extensive social science literature exists on the mostly adverse macroeconomic and institutional effects of a high reliance on mineral exports and revenues, we address the effects on the labour force employed by this industry. We perform a novel inter-continental – as well as dynamic-historical – comparative assessment of the living standards of the domestic copper mineworkers in the three countries from ca1920 to ca1960. There are important similarities and disparities in levels and trends of real wages and other welfare provisions. In explaining the gap across continents, we discuss labour shortage and labour provision, productivity, and mobilization. We also highlight the underlying role of colonialism in determining the inter-continental differences. Copper miners are further found to have been better paid than other workers in all three countries. [ABSTRACT FROM AUTHOR]

The public–private initiative Data Observatory Foundation was created to make large databases, such as those of astronomical observatories, available to expand and transfer of so-called "data-centric tasks" to various domains and thereby boost the development of the digital economy, data science and artificial intelligence in the country. However, in this article, we argue that data-centric initiatives like the Data Observatory Foundation may prove to be defuturing or enacting exhausted futures that reproduce the historical extractivism and coloniality of power in Latin America. Through a qualitative case study, we analyze the narrative and economic technologies of justification deployed by the Data Observatory Foundation to justify the value of its data and the organization itself. We discuss how the narratives and economic relationships developed by the Data Observatory Foundation manifest national wounds and technological dependency that enact a data-centric coloniality. Whether by attempting to define data as the copper of the future or establishing cloud computing credits as new salary tokens in the development of artificial intelligence, the Data Observatory Foundation reproduces past mentalities within innovation circuits. Rather than replicating futures based on modern colonial extractivist logics, we propose expanding possible engagements with data and speculating alternative designs. [ABSTRACT FROM AUTHOR]

There is a need to define mine tailings in a clear, precise, multidisciplinary, transdisciplinary, and holistic manner, considering not only geotechnical and hydraulic concepts but also integrating environmental and geochemical aspects with implications for the sustainability of mining. This article corresponds to an independent study that answers questions concerning the definition of mine tailings and the socio-environmental risks linked with mine tailings chemical composition by examining the practical experience of industrial-scale copper and gold mining projects in Chile and Peru. Definitions of concepts and analysis of key aspects in the responsible management of mine tailings, such as characterization of metallic–metalloid components, non-metallic components, metallurgical reagents, and risk identification, among others, are presented. Implications of potential environmental impacts from the generation of acid rock drainage (ARD) in mine tailings are discussed. Finally, the article concludes that mine tailings are potentially toxic to both communities and the environment, and cannot be considered as inert and innocuous materials; thus, mine tailings require safe, controlled, and responsible management with the application of the most high management standards, use of the best available technologies (BATs), use of best applicable practices (BAPs), and implementation of the best environmental practices (BEPs) to avoid risk and potential socio-environmental impact due to accidents or failure of tailings storage facilities (TSFs). [ABSTRACT FROM AUTHOR]

Copper ore is a non-renewable resource with lower ore grades, which means that the extraction of more rock material is required to produce the same amount of copper, implying a greater consumption of materials, reagents, water, and energy. Since there is a greater amount of copper sulfide present in nature, concentration using the bubble flotation method will generate a greater number of tailings. This article discusses the environmental issues resulting from tailings dams and how multi-criteria decision analysis can help prioritize those sites in order to promote circular economy measures to compensate for and reduce the impacts of this type of waste generated by the copper mining industry. This work aims to contribute to this purpose by taking information from abandoned and non-active tailings, which are currently present as a result of the lack of regulations in times prior to environmental obligations and because they are metallurgical waste from old operations that had metal recovery rates that were much lower than the current rates. We propose a model based on the multi-criteria Promethee method to prioritize the tailings dams according to the commercial value of the existing materials in the deposits. A case study with an application of the model to 103 dams in the mining region of Coquimbo in northern Chile is shown. [ABSTRACT FROM AUTHOR]

The copper mining industry is increasingly using artificial intelligence methods to improve copper production processes. Recent studies reveal the use of algorithms, such as Artificial Neural Network, Support Vector Machine, and Random Forest, among others, to develop models for predicting product quality. Other studies compare the predictive models developed with these machine learning algorithms in the mining industry as a whole. However, not many copper mining studies published compare the results of machine learning techniques for copper recovery prediction. This study makes a detailed comparison between three models for predicting copper recovery by leaching, using four datasets resulting from mining operations in Northern Chile. The algorithms used for developing the models were Random Forest, Support Vector Machine, and Artificial Neural Network. To validate these models, four indicators or values of merit were used: accuracy (acc), precision (p), recall (r), and Matthew's correlation coefficient (mcc). This paper describes the dataset preparation and the refinement of the threshold values used for the predictive variable most influential on the class (the copper recovery). Results show both a precision over 98.50% and also the model with the best behavior between the predicted and the real values. Finally, the obtained models have the following mean values: acc = 0.943, p = 88.47, r = 0.995, and mcc = 0.232. These values are highly competitive when compared with those obtained in similar studies using other approaches in the context. [ABSTRACT FROM AUTHOR]

Soil fauna can serve as an excellent tool for ecological assessment of soil quality. The earthworm Eisenia fetida L. is widely used as a bioindicator organism to assess the toxicity of metals, metalloids, and other pollutants. Many studies have shown that the concentrations of metals and metalloids toxic to earthworms are an order of magnitude lower in artificially contaminated soils than in industrially contaminated soils. The novelty of this study is that toxicity estimates were made using native industrially contaminated soils. The results of the two experiments demonstrate the potential use of earthworms for ecological assessment of soils contaminated with metals and metalloids due to copper mining activities in central Chile. The main contaminant in these soils was copper, but arsenic, commonly found in copper ore, was also present in the contaminated soils. In the short-term bioassay, E. fetida earthworms avoided the soil in response to increasing copper content. However, in long-term experiments, arsenic proved to be more toxic to earthworm reproduction, while copper had little effect. In this study, we present toxicity thresholds for copper and arsenic to E. fetida in industrially contaminated native soils. [ABSTRACT FROM AUTHOR]

An alternative process to obtain a high degree of dewatering tailings that produces a high-density product is presented in this article. This technology involves the combination of tailings particle grain size classification by hydrocyclones (HC) and tailings dewatering by horizontal vibratory screens (HVS). It makes it possible to dewater tailings to a high grade of performance. This alternative technology (HC-HVS) involves the recovery of water from the coarse fraction of tailings (sands) through two hydrocycloning stages, followed by a dewatering stage of cycloned tailings sands on horizontal vibratory screens, to reduce moisture content and turn it into a "cake". The resulting coarse fraction tailings are easily transported to a dry stack tailings storage facility (TSF). The fine fraction of tailings (slimes) can be dewatered on thickener equipment to recover part of the process water. Finally, this article describes the main benefits of this alternative dewatered tailings technology with an emphasis on (i) dewatering technology evolution over the last 17 years; (ii) process stages features; (iii) pilot test results; (iv) tailings properties analysis (such as particle grain size distribution, fines content) and (v) lessons learned about the experience gained in the operation of Mantos Blancos case study with dry stack tailings storage facility. [ABSTRACT FROM AUTHOR]

The generation of tailings in the world today is immense, since only ounces or pounds of metals are extracted for each ton of ore processed. In 2022, it was estimated that more than 14 billion metric tons of mining tailings were produced per year in the world. Currently, many environmental problems associated with tailings management in both Chile and Peru are related to the potential contamination of soil, water, and air. In this article, the environmental impacts caused by tailings storage facility accidents where spills have occurred are analyzed, describing and characterizing: (i) the magnitude of the impacted area, (ii) identification of the sources, i.e., exposure routes, receptors, and (iii) an interpretive analysis of the physicochemical quality of the spilled material, the soil, the water, and the air with respect to local and international regulations. The case studies analyzed in this article correspond to tailings spills derived from the extraction of precious metals (Au, Ag) and heavy metals (Cu, Pb, and Zn) present in the minerals that dominate Chilean and Peruvian mining. Finally, environmental management measures are proposed aimed at mitigating the environmental impacts caused by the spill and remediation alternatives for the sites impacted. [ABSTRACT FROM AUTHOR]

The mining industry faces diverse challenges to maintain sustainable production, particularly regarding critical water and energy supplies. As a significant player in the copper mining industry, Chile has become a global reference. Therefore, this research analyses the distinct challenges of the Chilean copper mining industry in terms of water and energy. We also identified ten key challenges that the Chilean copper mining industry must address to remain competitive and relevant. Several mining companies were examined to review and understand the different types of Environmental Management Initiatives (EMIs) adopted. The most prevailing strategies involved implementing Environmental Management Systems, which allow organisations to define, implement, and track their specific goals and standards. This review acknowledged four relevant water-related initiatives, including seawater use, community strategic plans, general environmental monitoring programs, and water recycling and recirculation systems. In terms of energy, the key initiatives included energy efficiency projects, the use of Non-Conventional Renewable Energy (NCRE), and mine process optimisation. The benefits of implementing EMIs are multiple, with the most relevant being ensuring continuous operation, cost reduction, and improved Social License to Operate (SLO) outcomes. [ABSTRACT FROM AUTHOR]

The main goal of grade control is the prediction of material destination based on all available data. The common approach to grade control is based on estimated maps obtained through kriging, inverse distance estimation, or nearest neighbor; however, capturing complex relations from data is not straightforward with such methodologies. Machine learning algorithms provide flexibility and simplicity when integrating data and incorporating complex patterns that cannot be easily accounted for with geostatistical workflows, leading to higher model accuracy and promotes better decision making. The methodology implemented in this case study uses machine learning algorithms to model copper grade, which is incorporated in an intrinsic collocated co-kriging framework as secondary information to generate a final grade model. The workflow presented (1) is not more difficult to implement compared to ordinary kriging, (2) allows for automatic data incorporation in a geostatistical framework and (3) improves grade control decision-making when compared to common approaches. The workflow is demonstrated on 10 blasts from Teck Resources Limited's Carmen de Andacollo copper mine in Chile and is compared to ordinary kriging and inverse distance. Two machine learning algorithms are implemented and evaluated for grade control decision-making. The algorithms considered are (1) an ensemble of radial basis function neural networks and (2) an ensemble of support vector regressors. These two algorithms are used to obtain an exhaustive secondary model used in copper grade estimation. Incorporating radial basis function neural networks improves the quality of the classified model, with average classification accuracy of 89% over 10 blasts and can reduce the volume of misclassified material on average over 10 blasts by 7% and 1% when compared to inverse distance, ordinary kriging and support vector regressor approach, respectively. [ABSTRACT FROM AUTHOR]

The Rosario and Ujina porphyry Cu-Mo deposits, together with porphyry copper mineralization at the nearby Quebrada Blanca deposit, constitute the third-largest concentration of copper mineralization associated with the Domeyko fault system in northern Chile. At Rosario, fault-hosted Cu-Ag-rich massive sulfide veins are associated with pyrophyllite-alunite-quartz altered rocks. The Rosario massive sulfide veins cut biotitealbite- magnetite, K-feldspar and illite-chlorite altered rocks associated with porphyry-style copper-molybdenum mineralization. Similar massive sulfide veins occur in the La Grande area, 1 to 2 km south of Rosario. Copper ore at Ujina is associated with a K-feldspar-biotite-altered quartz monzonite intrusion. The K-feldspar-biotite assemblage has been overprinted by white mica-chlorite alteration. New geochronologic data presented in this paper constrain the ages of hydrothermal activity in the Rosario and Ujina deposits. The 4Ar/39Ar biotite, illite, and alunite dates (at 2σ error), and a Re- Os molybdenite date (at 0.5% error) are reported for porphyritic rocks and hydrothermal alteration from the Rosario and Ujina mineralized centers. A weighted mean 40Ar/39Ar plateau age of 34.4 ± 0.3 Ma is obtained for igneous biotite in a monzonite porphyry that hosts copper mineralization at the Rosario deposit. Illite and hypogene alunite from separate overprinting alteration events yielded 40Ar/39Ar ages of 34.5 ± 0.5 Ma (plateau age) and 32.6 ± 0.3 Ma (plateau age), respectively. An Re-Os age of 33.3 ± 0.2 Ma for molybdenite at Rosario is slightly younger than the 40Ar/39Ar age of illite, but older than the alunite. A weighted mean plateau age of 32.7 ± 1.6 Ma for hypogene alunite from the La Grande Cu-Ag-(Au) vein south of Rosario is indistinguishable from the age of Rosario alunite. At Ujina, the weighted mean... [ABSTRACT FROM AUTHOR]

The geochemical stability, in terms of potential mobility and derived ecological and human health risks of potentially toxic elements (PTEs), of diverse fresh and old porphyry Cu-mine tailings from Chile was assessed through an integrated methodology comprising four interrelated investigation levels: (1) chemical composition and contamination degree of tailings by PTEs, (2) mineralogical characterization by X-ray diffraction and quantitative automated mineralogy analysis by scanning electron microscopy (QEMSCAN®), (3) partitioning and potential mobility of PTEs within the tailings by a sequential extraction procedure (SEP) and leaching tests, and (4) ecological risk assessment (ERA) and human health risk assessment (HHRA). According to pollution indices, Cu, As, Pb, and Mo are most concerning PTEs present in the tailings. SEP shows that major portion of the PTEs are strongly fixed as residual fraction, and thus are poorly mobilizable and bioavailable. Among the PTEs, Cu, As, and Mo were identified as the PTEs most prone to mobilization. Leaching tests show that a low fraction of PTEs is water-leachable. Seawater enhances Mn and As leaching, while process water increases the leaching of Cu, Mn, and Mo. Phosphate particularly promotes leaching of As and Cu, whereas it does not mobilize or even immobilize Pb in the tailings. ERA suggests that mainly old tailings pose a very high potential risk for ecological receptors (PERI = 663–3356), mostly due to Cu and As. HHRA indicates that the old tailings pose higher potential non-carcinogenic and carcinogenic health risks, while the risk decreases in the order ingestion > dermal > inhalation for both children and adults. Non carcinogenic and carcinogenic HHRA points to As as the main PTE of concern via ingestion pathway in the tailings. Overall, the results revealed that particularly old tailings, containing mixed slag-tailings, pose considerable risks to the environment and human health due to potential PTEs mobilization and this aspect requires scrutiny for proper tailings management, including storage, sealing, and eventual tailings reprocessing and/or site rehabilitation after closure. [ABSTRACT FROM AUTHOR]

State-owned Codelco is Chile''s largest company and the world''s largest producer of refined copper. The Codelco-owned El Teniente mine is at present the world''s largest underground mining operation. The mine is in the process of implementing plans to increase the average production rate from 95 000 to 126 000 t/day by the end of 2005. This paper describes the mine and some of the development work being carried out between the production and haulage level. It provides information on the boxhole boring units chosen for the work and the equipment modifications required to suit the El Teniente mine conditions. It further describes the application of the equipment and the performance monitoring system. Finally, it gives a short report on the results achieved during the 3-month performance evaluation period. [Copyright &y& Elsevier]

Primary copper production is a major activity in the mining sector of several countries. However, it is highly energy-intensive and poses important environmental hazards. In the case of Chile, the world' s largest copper producer (40% of world total), we examine its energy consumption and energy-related environmental implications over a time horizon of 25 years. Concerning the latter, we focus on greenhouse-gas (GHG) emissions, one of the most debated environmental issues. This paper follows-up our previous report in which the current situation was analyzed and a particular technical option for improving the energy efficiency and concurrently reducing GHG emissions was discussed. Estimated reference or base (BS) and mitigation (MS) scenarios are developed for the period ending in 2020. The former assesses the energy demand projected in accordance with production forecasts and specific energy consumption patterns (assuming that energy efficiency measures are adopted 'spontaneously') with their resultant GHG emissions, while the latter assumes induced actions intended to reduce emissions by adopting an aggressive policy of efficient energy use. For the year 2020, the main results are: (i) BS, 1214 t of CO[sub 2]/ton of refined copper content (49% lower than in 1994); (ii) MS, 1037 t of CO[sub 2]/t of refined copper content (56% lower than in 1994). CO[sub 2] emissions have been estimated considering both fuel and electricity process requirements. [ABSTRACT FROM AUTHOR]

Presents a technical comparison of the different medium-voltage alternatives for high-power regenerative conveyors at the Los Pelambres copper mine in Chile. Requirements for conveyor drives; Requirements for downhill conveyor drives; How the different solutions satisfy the requirements; Advantages and disadvantages of the solutions.

This article examines an early water war in Chile between local agriculturalists and the North American-owned El Teniente copper mine. It recovers a hitherto unknown history of ecological degradation caused by industrial copper mining during the twentieth century in Chile. It argues that contemporary water wars in Chile, usually viewed as a product of the privatisation of water rights in 1981 and the expansion of foreign investment in the mining sector during the 1990s, combined with the impact of global climate change, have roots in the appropriation of water in Andean rivers by North American companies at the beginning of the twentieth century. The article's thesis is that the Chilean state subsidised the mining industry by granting water rights and turning a blind eye to mining companies' contamination of rivers relied on by agriculturalists for irrigation. Finally, the article traces conservationist responses to the ecological crises produced by contamination of water and soil by the El Teniente mine, which was owned by the Kennecott Copper Company. It demonstrates that conservation of water resources was employed by estate owners as a means of asserting private property rights against the interests of mining companies. [ABSTRACT FROM AUTHOR]

Chile has many mine tailing deposits available for phytoremediation through the establishment of metal-tolerant plants. To guide such efforts, it is necessary to know whether roots exclude or take up metals, or if metals are mobilized to shoots. We evaluated a polyculture of ten native species 6 years after they were planted directly into tailings, amended with mycorrhiza before planting or planted with compost. All species were assessed for survival and hare damage. Growth, vigor, chlorophyll content index, and chlorophyll fluorescence were measured in seven species, and root and shoot concentrations of 11 metals and As were measured in five. All species had some level of stress, but there was no clear pattern related to foliar metal concentrations or amendments, the latter also having little effect on growth or survival. Copper, Fe, and Mo concentrations exceeded threshold toxicity levels for leaves and for animal feed in several species. Copper was most concentrated in the roots, and readily mobilized to leaves in three of the five species tested, but not in Prosopis chilensis (algarrobo) and Quillaja saponaria (quillay). Because of lower uptake overall, quillay is recommended for stabilizing tailings while also reducing transport to aerial tissues. [ABSTRACT FROM AUTHOR]

Given that most of the mines in Chile are situated in regions with high solar resources, solar power could play a significant role as an alternative solution to satisfy the electricity demand in the mining industry. This paper aims to investigate the feasibility of integrating solar power technology into copper concentrate plants (CCPs). Three commercial technologies (PV, CSP, and hybrid PV-CSP) are considered for integration into four existing CCPs of different sizes and located in different regions. To provide comprehensive analysis, the design, performance and economic assessment of 12 cases are carried and the investment costs are estimated taking into account characteristics of the Chilean market as well as the effect of scale. The performance analysis reveals a strong influence of the degradation rate on the electricity production of solar power plants. The first-year capacity factor of the CSP units is around 68% while it is around 32% for the case of PV units. Due to the degradation in the performance of the components, the lifetime-averaged capacity factor is about 9% lower than that of the first year. The economic assessment indicates that PV is the most suitable technology for integration into the CCPs. The Levelized Cost of Electricity (LCOE) of PV-CCPs ranges from 35.53 to 44.40 USD/MWhe, depending on the size and the location of the plant. The LCOE for the cases of CSP-CCPs and PV-CSP-CCPs ranges from 127.08 to 168.88 USD/MWhe and from 91.89 to 118.91 USD/MWhe, respectively. The modified internal rate of return (MIRR) of the PV-CCPs ranges from 8 to 9%, it discounted pack-back period (DPP) ranges from 5 to 6 years. The DPP PV-CSP-CCPs ranges from and from 15 to 23 years respectively. Overall, the CSP-CCPs are not atractive investments due to high LCOE, longer DPP, and MIRR. However, the sensitivity analysis revealed that its LCOE could be lowered by reducing the investment costs. For instance, a reduction of about 10% in the LCOE is possible if the specific investment costs of the TES is cut to about 10UDS/kW th. Image 1 • We focus on the integration of solar power technologies (SPTs) into the copper mining plants (CCPs). • 12 cases of solarized-CCPs is evaluated technically and economically. • The costs of solar power technologies in Chile (PV, CSP, and PV-CSP) are established. • The LCOE of PV-CCPs is about 4 times lower than that of CSP-CCPs and 50% that of PV-CSP-CCPs. • PV-CCPs and CSP-PV-CCPs are viable options but CSP-CCPs is viable only in sites of high solar radiation. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the author discusses various reports published within the issue on topics including religion as a force in politics, meanings behind the term "globalisation," and the role of the Chilean government in its copper mining industry.

In the long term, primary and secondary supply of refined copper satisfies demand. Numerous models exist to explain and predict demand and secondary supply; however, the projection of primary supply relies mostly on detailed knowledge of potential mining projects and on existing ore reserves and resources. Much discussion has occurred historically regarding the availability of resources and reserves for the future. Chile, being the largest copper producer, also has the largest reserves in the world; therefore, it retains its potential to be a key player in future supply. This article explores some of the most relevant resource and technological challenges that may emerge with an accelerated development of brownfield and greenfield copper mining projects in Chile through 2035, without considering economic, regulatory, and environmental constraints. A "Full Scenario" was created to accommodate these conditions and restrictions. It includes estimates of future ore reserves, copper production, plant capacity, ore grades, energy and water consumption, greenhouse gas (GHG) emissions, and generation of tailings. Maximum production would exceed 10 million tons of contained copper from 2027 to 2030, with a resulting decrease of ore grades and the growth of energy and water consumption. The growth of indirect GHG emissions through 2035 is estimated at 18.4% less than copper production growth, because all new electric energy for this scenario would be based on renewable energy. Also, all new water used by 38 out of the 42 mining projects considered would be seawater, and some of the continental water used in 2019 would cease to be used in mining. [ABSTRACT FROM AUTHOR]

The rate of growth of mining copper industry in Chile requires higher consumption of water, which is a resource limited in quality and quantity and a major point of concern in present times. In addition, the efficient use of water is restricted due to high levels of evaporation (10 to 15 (l/m2) per day), in particular at the north highland mining sites (Chile). On the contrary, the final disposal of tailings is mainly on pond, which loses water by evaporation and in some cases by percolation. An alternative are the paste thickeners, which generate stable paste (70% solids), reducing evaporation and percolation and therefore reducing water make up. Water is a resource with more demand as the industries are expanding, making the water recovery processes more of a necessity than a simple upgrade in efficiency. This technology was developed in Canada (early 80s) and it has widely been used in Australia (arid zones with similar weather conditions to Chile), although few plants are using this technology. The tendency in the near future is to move from open ponds to paste thickeners. One of the examples of this is Minera El Tesoro. This scenario requires developing technical capacity in both paste flow characterization and rheology modifiers (fluidity enhancer) in order to make possible the final disposal of this paste. In this context, a new technique is introduced and experimental results of fluidity modifiers are discussed. This study describes how water content affects the flow behavior and depositional geometry of tailings and silica flour pastes. The depositional angle determined from the flume tests, and the yield stresses is determined from slump test and a rheological model. Both techniques incorporate digital video and image analysis. The results indicate that the new technique can be incorporated in order to determine the proper solid content and modifiers to a given fluidity requirement. In addition, the experimental results showed that the pH controls strongly the fluid paste behavior. [ABSTRACT FROM AUTHOR]

Copyright of Boletín de Ciencias de la Tierra is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since its growth and popularization in the 1970's and 1980's, Neoliberalism has undermined efforts to regulate environmental contamination caused by corporations in United States and Chile. Under neoliberalist policies, when a corporation contaminates the environment, adequate environmental protection typically only occurs when the corporation involved can reap benefits from environmental compliance. When regulated corporations have little to gain, environmental policies fail to provide communities with long-term protection against contamination, or merely institute small scale, short-term solutions. This phenomenon will be illustrated by examining the parallel histories of the Bingham Canyon Copper Mine in Utah, and the El Salvador Copper Mine in Northern Chile. I will examine these mine's growth over the twentieth century and the contamination they disposed upon surrounding communities. Next, I will discuss landmark environmental policies that prompted these mines to begin remediating their pollution. Finally, I will explore how neoliberalism has impacted environmental remediation efforts both within these mining communities and the US and Chile as a whole. [ABSTRACT FROM AUTHOR]

Examining the conduits of production and circulation that link the extraction of copper in Chile to its storage and use in China, this article explores the political dimensions of the logistical techniques and technologies that enable these processes. We approach copper as a material element that due to its capacity to conduct electricity provides conditions of possibility for contemporary digital capitalism. At the same time, we consider the elements that constitute logistics as a political force by asking how logistics operates in parallel, partnership, and rivalry to forms of state and international order themselves in uncertain transformation. Empirically, the article stems from research conducted in Chile, specifically in the port of Valparaíso, the Andina mine run by the country's state owned copper mining company CODELCO, and the copper smelter run by the same company on the coast at Ventanas. On this basis, we ask how the production and circulation of copper has mutated with shifting logistical arrangements that respond to the geopolitical position of China, the financialization of trade in base metals, the rise of business models based in data extraction, and workers' struggles in times of labor precarization. [ABSTRACT FROM AUTHOR]

Trafficking the Earth documents the extraction of copper and nitrate from the Atacama Desert, Chile, and the accumulation of their values in metropolitan sites, the City of London and the houses of the British merchants in particular. Presented here as a photo-essay, it juxtaposes words and images to create constellations of meaning intended to disrupt a linear narrative of a past running smoothly into the present. The essay draws upon and tries to demonstrate a documentary practice that captures the collisions of time and the connected spaces of copper and nitrate mining as exemplary of an extractivist economy. The subject of the photography is the surplus of mining, its ruins, rubble and waste, which is offered not as a straightforward set of pictures but rather as perspectives through which the effects of global capitalism can be understood. [ABSTRACT FROM AUTHOR]

The authors propose an extraction schedule for an underground copper mine. The schedule maximizes profits, considers uncertainties because of equipment failure, and shows that a stochastic-based solution can achieve the same expected profits as a deterministic-based solution. We propose an extraction schedule for the Chuquicamata underground copper mine in Chile. The schedule maximizes profits while adhering to all operational and geomechanical requirements involved in proper removal of the material. We include extraction capacity uncertainties due to failure in equipment, specifically to the overland conveyor, which we find to be the most critical component in the extraction process. First we present the extraction plan based on a deterministic model, which does not assume uncertainty in the extraction capacity and represents the solution that the mine can implement without using the results of this study. Then we extend this model to a stochastic setting by generating different scenarios for capacity values in subsequent periods. We construct a multistage model that handles economic downside risk arising from this uncertainty by penalizing plans that deviate from an ex ante profit target in one or more scenarios. Simulation results show that a stochastic-based solution can achieve the same expected profits as the deterministic-based solution. However, the earnings of the stochastic-based solution average 5% more for scenarios in which earnings are below the 10th percentile. If we choose a target 2% below the expected profit obtained by the deterministic-based solution, this average increases from 5% to 9%. [ABSTRACT FROM AUTHOR]

Chile is the principal producer of copper with a total of 5.8 million tonnes fine copper production in 2013. Chilean mining industry currently faces a projected increase in waste production, depleting water resources in the arid mining regions of the north and a lack of fossil fuel energy sources. In this study, a review of the historical background of environmental practices in Chile is presented, focused between 1970 and 2010. A review of the current state of sustainable development, comprising energy, water, stakeholder participation, environmental impacts and institutional decentralisation in the mining industry is presented. [ABSTRACT FROM AUTHOR]

A methodology is presented for deciding the location of a third ore crusher to be installed at Chile’s Chuquicamata copper mine. The proposed approach determines which location alternative exhibits the minimum capital and operating costs when equipment failure probability is considered. Two alternative location configurations are evaluated using the stationary probabilities of a Markov chain model, and the results are validated with a discrete-event simulation model. The Markov model generates insights into the relationships between the variables that a discrete-event simulation cannot provide, and does so without the latter’s greater costs and complexities of modelling, solving and calibration. [ABSTRACT FROM PUBLISHER]

Mining cycles have had an enormous impact in the evolution of the localisation of economic activity, in particular of industry, in Chile. The nitrate cycle was characterised by a labour-intensive extraction process and activity which was geographically very concentrated. The copper cycle was geographically more dispersed and its activity more capital-intensive. We stress the role played by the State in the latter de-concentration due to the impact of regional development policies and assess the importance of factor endowments and agglomeration economies, in the localisation of the manufacture. [ABSTRACT FROM AUTHOR]