Chilean Copper Mine Research Articles

Characterisation of the internal friction angle of waste rock material from large triaxial tests using the contact dynamics method

ABSTRACT The Chilean copper mining industry generates large amounts of waste rock materials. These structures must be designed, operated, and closed considering their physical stability. Although these structures generally do not present physical stability problems, superficial failures may occur, where waste rock material is subjected to low confining pressures. The identification of the internal friction angle, necessary for stability calculations, is based on the characterisation of these materials under high confining pressures. This assumption is not representative of the loading conditions in the superficial layers. To address this issue, numerical large-scale triaxial tests, using the contact dynamics method, are performed to identify the internal friction angle of these materials under low confining pressures. To model these material, irregular polyhedrons were generated using statistical data of crushed aggregates, considering the morphology and the particle size distribution from experimental waste rock materials. The proposed numerical approach was validated by comparing it to literature data for confining pressures over 0.5 MPa. Our results indicate that the internal friction angle stabilises at 39° for confining pressures below 0.1 MPa. This study provides important insights into the physical stability of waste rock dumps and contributes to the development of more accurate stability calculations for these structures.

Desalination investment for copper mining: Barriers and opportunities in Chile

Global decarbonisation goals will not be met without a significant increase in the supply of critical minerals. However, there are numerous economic, environmental, social and regulatory barriers which may hinder potential future supplies. This study therefore examines the interlinkages of mineral extraction in the world's largest copper producing nation, Chile. Framed within the context of the mining industry's plans to significantly expand its use of desalination to alleviate water scarcity issues, as well as demands for the sector to leverage its investment in water infrastructure for sustainable development goals, this study identifies the primary barriers and opportunities associated with increased investment and expansion of desalination infrastructure within the Chilean copper mining sector. It applies an inductive, mixed-methods approach to gain cross-sectoral insights from 18 relevant stakeholders over two rounds of surveys, quantitatively determining the relative importance of the issues identified. The analysis finds that desalination's capacity to allow the mining industry to operate independently of freshwater availability, as well its potential role in alleviating broader water scarcity issues were the primary opportunities. The study further finds widespread support for initiatives to integrate renewables into desalination plants, incorporate public acceptance into the planning procedure, and ensure that mining continues to reduce its freshwater consumption, presenting a clear opportunity for sustainable expansion. The results also showed that regulatory and political uncertainty, followed by the lack of public acceptance of desalination are considerable barriers to its expansion. Further, quantitative analysis of perceived risks also highlighted significant disagreement between mining and non-mining stakeholder groups regarding the environmental impacts associated with desalination, indicating an overall lack of consensus. This study therefore invites further research into consensus-building around the issues identified. A further investigation of why particular perspectives are more prevalent among certain stakeholder groups is also suggested.

The use of seawater in copper hydrometallurgical processing in Chile: A review

Seawater has become a viable alternative for different uses in copper hydrometallurgy. In this paper we review the main physical and chemical characteristics of seawater and how these influence copper production. Reliable data on the use of continental water are reported, and the current use and consumption of seawater in the Chilean mining industry is analysed, indicating the main areas of use and the main problems encountered. Additionally, the influence of the elements in seawaterthat have the most influence on the extractive metallurgy of copper are considered. The Chilean copper mining industry currently consumes approximately 4.1 m3/s of seawater, which corresponds to 25% of the total water used. The use of seawater for the leaching of copper sulphide minerals, such as chalcopyrite, is beneficial because it provides 20 g/L of chloride, thereby improving copper dissolution kinetics.

The environmental and economic case for valuing water recovery and its relationship with tailings storage conservation

Alternative tailings disposal methods such as dry stack are often neglected as optimal mine waste disposal methods due to perceived high cost. However, the transition from traditional wet tailings disposal to dry stack and alternative tailings disposal is critical for decreasing freshwater consumption and de-risking projects. This research presents an open-source techno-economic model which allows for the comparison of water use and cost between different tailings disposal-related equipment, addressing a major gap in models available for operators and early technology decision-makers. A case study of a Chilean copper mine is evaluated through the model to optimize the dewatering equipment choice. The findings indicate a substantial technical, environmental and economic return on the thickener control system and hydro-cyclone compared to desalinated and pumped water. Early economic modeling can quickly develop a business case for new water and energy-saving technologies while creating shared de-risked technical, ESG, and business team drivers.

Optimization of the SAG Grinding Process Using Statistical Analysis and Machine Learning: A Case Study of the Chilean Copper Mining Industry.

Considering the continuous increase in production costs and resource optimization, more than a strategic objective has become imperative in the copper mining industry. In the search to improve the efficiency in the use of resources, the present work develops models of a semi-autogenous grinding (SAG) mill using statistical analysis and machine learning (ML) techniques (regression, decision trees, and artificial neural networks). The hypotheses studied aim to improve the process's productive indicators, such as production and energy consumption. The simulation of the digital model captures an increase in production of 4.42% as a function of mineral fragmentation, while there is potential to increase production by decreasing the mill rotational speed, which has a decrease in energy consumption of 7.62% for all linear age configurations. Considering the performance of machine learning in the adjustment of complex models such as SAG grinding, the application of these tools in the mineral processing industry has the potential to increase the efficiency of these processes, either by improving production indicators or by saving energy consumption. Finally, the incorporation of these techniques in the aggregate management of processes such as the Mine to Mill paradigm, or the development of models that consider the uncertainty of the explanatory variables, could further increase the performance of productive indicators at the industrial scale.

Commodity price and fatalities in mining – Evidence from copper regions in Chile

On October 13th, 2010, the world was glued to the TV screen to watch the rescue of the 33 miners that spent 69 days trapped 700 m underground in a Chilean copper mine. While the 33 miners were rescued alive, 43 copper miners died in Chile the same year due to accidents in mining operations – the most significant number of mining fatalities in more than 20 years. The same year, copper reached its highest average annual price in history. Does this mean that high commodity prices induce a higher number of fatal accidents in mining operations? This paper addresses this question using 21 years of accident data in copper mines in Chile. We find that when the international price of copper surpasses approx. $5200/tonne, there is a strong positive correlation with the number of fatalities in copper mining. Scrutinizing such findings, we observe that the relationship mainly occurs with companies’ direct employees, while the number of deaths within contractors does not vary along with the copper price. Our results suggest that in the wave of high commodity prices, mining operations intensify their production processes, including rushing to bring back medium-sized operation sites that have previously been in care and maintenance, and which negatively affects the safety of operations.

Innovation and IP Rights in the Chilean Copper Mining Sector: The Role of the Mining, Equipment, Technology and Services Firms

Innovation and IP Rights in the Chilean Copper Mining Sector: The Role of the Mining, Equipment, Technology and Services Firms

A unified metric for costing tailings dams and the consequences for tailings management

Early-stage decision making on tailings disposal technology has significant and long-lasting impacts on mine economics and risk. The assumed favorable economics of slurried tailings disposal has had wide-reaching implications on the uptake of dewatered tailings technology such as paste thickeners, dry-stack and cyclone tails. This paper addresses the need for a comparable metric across tailings disposal options by the development of a financial model and unified costing metric which can be used during a mine's initial design choice and decision-making stages. The financial model developed estimates the actual cost of tailings dams in USD per dry metric tonne working within the framework of Canadian disclosure requirements. The method's utility is illustrated by applying the model to a case study of a Chilean copper mine. This case study demonstrates the usefulness of a unified metric for application in mine development proposals to improve the financial reporting transparency of TSFs. A unified cost metric would result in companies assessing their financial obligations more systematically, thereby promoting decision-making around alternatives to tailings dams in the longer term.

Environmental Management Strategies in the Copper Mining Industry in Chile to Address Water and Energy Challenges—Review

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.

Gateways or backdoors to development? Filtering mechanisms and territorial embeddedness in the Chilean copper GPN’s urban system

AbstractThis paper analyses the role played by different urban nodes in the Chilean copper mining Global Production Network (GPN), and how filtering mechanisms act in favour of the capital city, limiting the territorial embeddedness of extractive industry in resource peripheries. In doing so, we make three contributions to the literature. First, in addition to observing gateway cities (those connecting the mining hinterlands to the global economy), we propose an intermediate category in urban hierarchies which we label the “backdoor city” (those that can perform one or more functions of a gateway city but lack chances for value capture and sustainable development outcomes). Second, we analyse the filtering mechanisms that work to the detriment of resources peripheries. Third, we analyse how these mechanisms reduce the territorial embeddedness of mining activity across the Chilean urban hierarchy. Our main results show that the capital city of Santiago stands out as the only gateway city in the country, and Antofagasta acts as a backdoor city for the Chilean resource peripheries where the extractive activity is weakly embedded, limiting their development opportunities.

Selective Extraction of Cobalt and Copper from Chilean Mine Water by Ion Exchange Resin

Heavy metal-containing waste has become one of heavy environmental problems. Processing of such waste accumulated at waste dumps to extract valuable components is commercially beneficial activity and, in addition, decreases environmental impact. In this study, Lewatit MonoPlus TP 207 (TP 207) ion exchange resin was evaluated for its suitability for selective removal of cobalt (Co) and copper (Cu) from mine waste waters, generated by heap leaching waste materials at a Chilean copper mine. In series of laboratory scale fixed-bed ion exchange column tests, the effects of process parameters, such as waste water flow rate and regenerant (sulfuric acid) concentration, were studied in both waste water treatment by the ion exchange resin process and the resin regeneration (metals eluting) process. The regeneration process tests were performed using 1 % and 10 % sulfuric acid. The best separation of the metals (in the eluting process) was achieved with regeneration of TP 207 resin using 1 % sulfuric acid at flow rate of 1 bed volume per hour (BV/h).

Transparency on greenhouse gas emissions from mining to enable climate change mitigation

The climate change impacts of mining are often not fully accounted for, although the environmental impact of mineral extraction more generally is widely studied. Copper mining can serve as a case study to analyse the measurable pathways by which mining contributes to climate change through direct and indirect greenhouse gas emissions. For example, mining, processing and transportation require fuel and electricity, and the decomposition of carbonate minerals, employed to reduce environmental impacts, also releases carbon dioxide. Overall, we estimate that greenhouse gas emissions associated with primary mineral and metal production was equivalent to approximately 10% of the total global energy-related greenhouse gas emissions in 2018. For copper mining, fuel consumption increased by 130% and electricity consumption increased by 32% per unit of mined copper in Chile from 2001 to 2017, largely due to decreasing ore grade. This trend of increasing energy demand to produce the same quantity of some metals compounds the problems of increased metal demand due to the pressures of new technologies and increasing population. For green technologies to be implemented effectively, it is necessary that the mining industry and regulators accurately and transparently account for greenhouse gas emissions to implement mitigation strategies. Direct and indirect greenhouse gas emissions from mining for green technologies need to be accurately and transparently accounted for, as highlighted by a case study of Chilean copper mining.

Analyzing the potential for solar thermal energy utilization in the Chilean copper mining industry

Copper mining is the largest industry and energy consumer in Chile, utilizing heat from imported fossil fuels of which Chile is not a producer. The goals for decarbonization present opportunities to analyze how the Chilean industry can become sustainable with significant shares of renewable energy including solar heat. The present study analyzes the integration of solar heating to the copper refining process in order to gain insights on the technical, economical, and emissions performance of solar heating systems for the largest copper mining operations in Chile. The solar technologies considered in the analysis are flat plate, evacuated tube, and parabolic trough collectors. The results are validated by comparing with publicly available data from existing solar heating plants in copper mining facilities showing that solar plants are able to supply partially the thermal energy demand, although at different costs in terms of capital and operation and maintenance requirements. The economic analysis indicates that with current fossil fuel prices, solar heating technologies are a valid alternative for cost and emissions reduction in copper mining. Flat plate collectors show the lowest cost for solar heat when compared to evacuated tube and parabolic trough systems considering identical sets of technical and financial parameters. The parametric and sensitivity analysis indicate that the conditions under which solar heating is competitive with traditional fossil-fired heaters. which might still be required as backup systems in order to provide heat in a 24/7 regime, and in all the cases analyzed, a substantial reduction in CO2 emissions can be achieved.

Uranium and molybdenum recovery from copper leaching solutions using ion exchange

This work shows the technical feasibility to recover uranium and molybdenum from industrial copper leaching solutions (PLS). Both were obtained as by-products from hydrometallurgical operations of the Chilean copper mining industry, using the ion exchange technique. This process recovered uranium and molybdenum, without disturbing or changing the normal operation of the overall copper production process. Uranium concentration was 17 mg/L, while molybdenum concentration was 50 mg/L. Four different anionic resins were tested, along with the influence of impurities over the breakthrough and saturation points achieved. In a first instance, two resins were chosen based on their Langmuir parameters, namely, maximum load capacity (Qmax) and separation factor (RL): L-MP62 and M43. The overall dynamic process consisted in a pre-conditioning step for the resin, using a weak hydrochloric acid solution. Next, the copper PLS solution feeds the fixed bed of the ion exchange column. Once the PLS solution saturates the anionic resin, a hydrochloric solution extracts uranium, and a sodium hydroxide solution extracts molybdenum. The final products were purified elution solutions with 500 mg/L uranium and 800 mg/L molybdenum, respectively.

Museums and mining technologies

ABSTRACTThis article has a twofold purpose, first to explore how the founding of museums helps the mining industry to create a new way to look at what becomes natural in landscapes that are intervened by mining operations, and second to analyze how this new way of looking at the landscape ignites a process of recontextualization having a material impact on the territories. As part of this discussion, this article reveals how the technologies of mining production have evolved, facilitating the companies’ material production, and how the mining museum becomes a fundamental part of this technological development. This article looks at two mining museums owned or funded by the Chilean copper mine Los Pelambres, the ‘Museum of Copper and Sustainable Development’, located in Los Vilos next to Los Chungungos dock, and the ‘Andróniko Luksic Mining Center’, located in the engineering department at the Pontificia Universidad Católica in Santiago. These museums are funded by the mining company Los Pelambres and one of them is currently managed by the company.

Increasing and Diminishing Returns – Africa’s Opportunity to Develop

Marshall’s observation also applies to today’s migration patterns: from countries where most activities are subject to constant or diminishing returns to countries whose key economic activities are subject to increasing returns to scale. Diminishing returns occur when one factor of production is limited by nature, which means that it occurs in agriculture, mining, and fisheries. Normally the best land, the best ore, and the richest fishing grounds are exploited first, and – after a point – the more a country specializes in these activities, the poorer it gets. OECD (2018) shows how this occurs in Chilean copper mining: every ton of copper is produced with a higher cost than the previous ton. In Alfred Marshall’s theory, the ‘Law of Diminishing Returns’ is juxtaposed with ‘The Law of Increasing Returns’, also called economies of scale. Here we find the opposite phenomenon; the larger the volume of production, the cheaper the next unit of production becomes. Traditionally economies of scale were mainly found in manufacturing industry, and increasing returns combined with technological change has for centuries been the main driving force of economic growth. Increasing returns creates imperfect competition, market power and large barriers to entry for challengers – companies or nations – making it difficult for them to enter these industries. In contrast to the rents produced under conditions of increasing returns, raw materials – commodities – on the other hand, are subject to perfect markets, and productivity improvements spread as lowered prices. This is the essence of the theory which explains why former World Bank Chief Economist Justin Yifu Lin was correct when he asserted that ‘Except for a few oil-exporting countries, no countries have ever gotten rich without industrialization first’ (Lin 2012 : 350).

Electrokinetic remediation of manganese and zinc in copper mine tailings.

The scope of this work is to determine the effect of initial acidity and electric field intensity on the Electrokinetic Remediation of manganese and zinc from mine tailings from a Chilean copper mine. To achieve this objective, experiments were carried out focusing on the effect of the applied electric field (1 and 2 V cm-1), the H2SO4 concentration during pretreatment (1 and 2 mol L-1) and the interaction between these factors in manganese and zinc concentration. From the obtained results, manganese and zinc can be removed from the analyzed tailings, with the maximum net removal 31.88% and 17.95%, respectively. The enhancement of electromigration was proven by an Analysis of Variance with a significance level of 10% for the soluble and total metal concentration in the cathodic zone, where total concentration was increased to 24% and 11% for zinc and manganese, respectively.

On resource depletion and productivity: The case of the Chilean copper industry

How resource depletion affects productivity is a crucial question for several industries. In fact, several natural resource-exporting countries have seen their productivity levels affected by resource depletion. Nevertheless, usually, it is not clear what the real productivity growth is, without discarding the effects of resource depletion in the production structure. The main aim of the paper is to empirically answer a relevant issue regarding the Chilean copper mining industry, which is, the slowdown of its productivity in the last decade, considering in the analysis the role of resource depletion. In particular, we consider resource depletion to be an exogenous and unpaid force that opposes technological change and hence increases costs through time, capturing in this way some stylized facts of, for example, the mining and fishing industries. The decomposition framework was applied to the Chilean copper mining industry, one of the most important in the world, using data from the period of 1985–2015. The econometric results were robust and pointed to the fact that the productivity fell sharply during the period; however, it did not fall as much as the traditional estimation methods pointed out. Our model showed that as much as 15% of this decline was due to the increase of the resource depletion variable (copper ore grade).

The effect of mine aging on the evolution of environmental footprint indicators in the Chilean copper mining industry 2001–2015

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.

Slurry rheology prediction based on hyperspectral characterization models for minerals quantification

The presence of clays in mineral processing offers a number of challenges that range from valuable species recovery to the transport of tailings. In particular, when the abundance of one or more clay types increases, the rheology may be significantly affected. In this paper, the feasibility of using hyperspectral characterization to estimate rheological properties of mineral suspensions was studied. Towards this purpose, a set of rheology measurements was made for slurries of different composition, combining up to three out of five minerals: three clay minerals (two bentonites from different sources and kaolin), quartz and white mica, which are the main gangue minerals present in the Chilean copper mining industry. Using a Bingham Plastic flow model, a set of ternary plots for Bingham viscosity and yield stress was obtained. Results show counter-intuitive behavior for kaolin-white mica mixtures, showing a minimum for viscosity at a 2:3 ratio respectively. In addition, mechanisms for lowering the high viscosity reached by bentonite slurries were assessed. Modelling of the hyperspectral data produced high accuracy estimates of the mineral abundances, enabling an accurate determination of the respective samples position in the ternary mineralogy-rheology diagrams.