Rio Tinto Research Articles

Source apportionment of potentially toxic PM10 near a vast metallic ore mine and health risk assessment for residents exposed

Mining is an economic activity that traditionally releases large amounts of particulate matter into the atmosphere because of the procedures required to process the mineral. In particular, polymetallic ores are environmentally harmful as they can enrich potentially toxic elements, which may cause adverse effects to humans and ecosystems due to their toxicity. The aim was to assess the impact on health of this type of mining on nearby populations. Accordingly, it was conducted an extensive PM10 sampling campaign during the entirety of 2021 through a total of 248 filters placed in three villages close to the Rio Tinto district (Southwest Spain), which is one of the largest Cu mines in the world. A total of 58 major and trace elements were analysed, along with organic carbon/elemental carbon, cations, and anions. The mean PM10 concentrations were high during spring (47 μgPM10⋅m−3) and summer (56 μgPM10⋅m−3) in the population closest to the mine, wherein values surpassed the annual and daily limit values, but were lower in the other two villages. Moreover, high enrichment of As (annual maximum mean of 6.2 ng⋅m−3), Cu (70 ng⋅m−3), Pb (19 ng⋅m−3), and Zn (50 ng⋅m−3) was observed in all locations. A positive matrix factorization (PMF) was primarily used to assess the origins of this particulate matter, revealing that the impact of the mine reduced considerably over a long distance, with contributions ranging from 36% at the mine's outskirts to 8% further away from it, which coincides with the features of the mine during the abandonment phase (2001–2015). Despite this, the risk assessment revealed that the carcinogens were within the permissible exposure limits even in the closest village, indicating a minor concern for the inhabitants from a toxicological perspective.

Rio Tinto as a niche for acidophilus enzymes of industrial relevance.

Lignocellulosic residues are amongst the most abundant waste products on Earth. Therefore, there is an increasing interest in the utilization of these residues for bioethanol production and for biorefineries to produce compounds of industrial interest. Enzymes that breakdown cellulose and hemicellulose into oligomers and monosaccharides are required in these processes and cellulolytic enzymes with optimum activity at a low pH area are desirable for industrial processes. Here, we explore the fungal biodiversity of Rıo Tinto, the largest acidic ecosystem on Earth, as far as the secretion of cellulolytic enzymes is concerned. Using colorimetric and industrial substrates, we show that a high proportion of the fungi present in this extremophilic environment secrete a wide range of enzymes that are able to hydrolyze cellulose and hemicellulose at acidic pH (4.5-5). Shotgun proteomic analysis of the secretomes of some of these fungi has identified different cellulases and hemicellulolytic enzymes as well as a number of auxiliary enzymes. Supplementation of pre-industrial cocktails from Myceliophtora with Rio Tinto secretomes increased the amount of monosaccharides released from corn stover or sugar cane straw. We conclude that the Rio Tinto fungi display a good variety of hydrolytic enzymes with high industrial potential.

Critical reflections on the Juukan Gorge parliamentary inquiry and prospects for industry change

In May 2020, when Rio Tinto destroyed ancient rockshelters in Western Australia to expand an iron ore mine, public outcry triggered a parliamentary inquiry. The value and effect of public sector inquiries have been debated for over a century. While the Juukan Gorge inquiry overlooked some important issues, it succeeded in illuminating critical flaws in company, regulatory and administrative systems that trade on injustice. These issues have not been altogether neglected by past state and federal governments, but previous inquiries failed to drive meaningful reform. We conclude that while systemic change seems improbable, the evolving political milieu in Australia may offer prospects for industry change.

Perspectives on Closure and Revitalisation of Extraction Sites and Sustainability: A Q-Methodology Study

Closure and revitalisation are essential steps in the life cycle of a mineral extraction site. Proper planning and execution can counteract potential negative impacts caused by extraction activities and allow a positive impact to be left on the post-closure region. Decisions on these steps are not made solely by the extraction company; legislators and the public also exert influence. Different opinions and expectations on closure and revitalisation can lead to tensions between actors. Thus, knowing diverse opinions and expectations and considering them in planning contributes to a successful implementation of measures. Using Q-methodology in a study focused on selected EIT RIS countries, we identified five viewpoints on the closure and revitalisation of an extraction site. The statements for this study have been developed based on international and company standards for closure and revitalisation, namely ICMM, IRMA, AngloAmerican and Rio Tinto, which we then also used for comparison in order to see how they relate to the five resulting viewpoints. Across all viewpoints, our results reveal a preference for environmental considerations, followed by social and economic concerns. Even though this paper considers closure and revitalisation separately from mineral extraction, these processes are intertwined. Thus, a sustainable planning and management of the extraction process itself contributes to a successful and sustainable post-closure landscape.

Spain’s First Environmental Campaign: Free Market Liberalism Under Challenge

ABSTRACT In February 1888, the workforce at the British-owned Rio Tinto mines went on strike seeking better wages and conditions. As part of their struggle, the miners joined an alliance of local landowners and communities to oppose the company’s open-air calcination operations. These threw vast quantities of poisonous sulphur dioxide into the atmosphere, severely damaging the health of workers and local communities. This paper suggests the strike, the first such environmental action in Spain, was an example of broad-based political resistance to the application of free market ideology to the process of industrialization. It builds on Karl Polanyi’s theory that the unconstrained operation of free markets in the fields of land, labour and finance, advocated by radical economic liberalism, results in existential threats to the social fabric of nations. This leads groups with widely different interests to unite and press for state intervention to curtail the freedom of markets, in the wider interest of society’s survival. The Rio Tinto strike which ended with the massacre of a defenceless crowd of protesters and strikers, provides a good example of Polanyi’s proposition, as well as illuminating a tragic and often over-looked event in the history of environmental studies.

Detoxification of effluents with cyanide. Application on a cyanide gossan mineral

The process of cyanidation is employed to extract the gold and silver components from minerals. As a result of this procedure, the production of effluents and solid waste occurs, wherein the presence of free cyanide is observed as the most hazardous form. The application of degrading processes can facilitate the transformation of cyanides in solution into forms that are less hazardous. The aim of this study is to investigate the degradation of cyanide effluents using either sodium hypochlorite or ozone. The primary purpose is to identify the optimal conditions for the degradation of total cyanide while ensuring the absence of any other pollutants. The cyanidation process will be implemented under optimal conditions for the purpose of recovering gold and silver from Gossan ore. The gossan ore sourced from Rio Tinto in Huelva, Spain, finds application in the detoxification of cyanide effluents. Characterization techniques are employed to identify the predominant elements present in the ore, namely iron (25.0%) and silicon (21.2%). The process of cyanide breakdown with ozone treatment yields carbonates, which are significantly more ecologically sustainable in comparison to cyanates formed by hypochlorite. Nevertheless, the utilization of ozone in mining is limited due to some disadvantages, namely its exorbitant cost and excessive consumption.

First record of Sebekia oxycephala (Pentastomida: Sebekidae) infecting Helicops angulatus (Reptilia: Colubridae) in Northeast Brazil.

In this study, we investigated the infection by pulmonary parasites in the water snake Helicops angulatus. We found four nymphs of the pentastomide parasite Sebekia oxycephala, parasitizing two adult females H. angulatus collected in the municipality of Rio Tinto, Paraíba, Brazil. This occurrence is likely due to the nymphs of this parasite directly infecting aquatic intermediate hosts, such as fish. The result of this study represents the first record of pentastomid infecting H. angulatus.

Use of NASA’s AVIRIS-NG imagery for environmental mapping at the Rio Tinto mining district, southwestern Spain

Airborne hyperspectral imagery recorded by the NASA’s Next Generation Advanced Visible/Infrared Imaging Spectrometer (AVIRIS-NG) was analyzed for environmental mapping of the Rio Tinto mining district in southwestern Spain. The Rio Tinto mining district contains a giant world-class polymetallic sulfide deposit that has been mined from the antiquity to the modern times. The mining and ore processing activities have created large areas covered by sulfide-bearing mine waste, tailings, flooded open pits, slags, galleries and other mining facilities. The sulfide-bearing mine waste generates acid mine drainage (AMD) that contaminates the fluvial network. The Rio Tinto River is one of most AMD contaminated rivers in the world. Many secondary minerals associated with sulfide-bearing mine waste have diagnostic reflectance spectra due to absorptions of ferric and ferrous iron, water and hydroxyl. The mapping of the surface distribution of these secondary minerals is useful for environmental studies. The AVIRIS-NG radiance data were converted to surface reflectance using the Fast Line-of-sight Atmospheric Analysis of Hypercubes model. The AVIRIS-NG imagery was analyzed using the spectral mixture analysis. The AVIRIS-NG accurately mapped acid water, jarosite, goethite, hematite, melanterite, rozenite, copiapite, gypsum, undifferentiated metal sulfate hydrates, sericite and kaolinite. Acid waters occur in the tailings ponds, in the Rio Tinto River, and in various other locations within the study area. Jarosite, goethite and hematite are the predominant secondary iron minerals in the areas covered by sulfide-bearing mine waste. These secondary iron minerals are indicators of acid mine drainage generation. In few locations were distinguished from the AVIRIS-NG data the mineral melanterite and its dehydration product rozenite. The study gives new information on the surface distribution of environmentally important secondary iron minerals in the Rio Tinto mining district in southwestern Spain. The mapping results produced by the analysis of the AVIRIS-NG data can be useful to the environmental studies concerned with the pollution from acid mine drainage of the fluvial network of the area.Uso de imagens AVIRIS-NG da NASA para mapeamento ambiental no distrito de mineração de Rio Tinto, sudoeste da EspanhaResumoAs imagens hiperespectrais aerotransportadas registradas pelo espectrômetro avançado de imagens visíveis/infravermelhas da NASA (AVIRIS-NG) foram analisadas para o mapeamento ambiental do distrito de mineração de Rio Tinto, no sudoeste da Espanha. O distrito de mineração de Rio Tinto contém um gigantesco depósito de sulfeto polimetálico de classe mundial que foi extraído desde a antiguidade até os tempos modernos. As atividades de mineração e processamento de minério criaram grandes áreas cobertas por resíduos de mineração contendo sulfeto, rejeitos, minas a céu aberto inundadas, escórias, galerias e outras instalações de mineração. Os rejeitos de mineração contendo sulfetos geram drenagem ácida de mina (DAM) que contamina a rede fluvial. O rio Rio Tinto é um dos rios mais contaminados pela AMD no mundo. Muitos minerais secundários associados com rejeitos de mina contendo sulfetos têm espectros de refletância diagnósticos devido a absorções de ferro férrico e ferroso, água e hidroxila. O mapeamento da distribuição superficial desses minerais secundários é útil para estudos ambientais. Os dados de radiância do AVIRIS-NG foram convertidos em refletância de superfície usando o modelo de Análise Atmosférica de Linha de Visão Rápida de Hipercubos. As imagens do AVIRIS-NG foram analisadas usando a análise de mistura espectral. O AVIRIS-NG mapeou com precisão água ácida, jarosita, goethita, hematita, melanterita, rozenita, copiapita, gesso, hidratos de sulfato de metal indiferenciado, sericita e caulinita. Águas ácidas ocorrem nas lagoas de rejeitos, no rio Rio Tinto e em vários outros locais dentro da área de estudo. Jarosita, goetita e hematita são os minerais de ferro secundários predominantes nas áreas cobertas por rejeitos de mineração contendo sulfetos. Esses minerais de ferro secundários são indicadores de geração de drenagem ácida de mina. Em poucos locais foram distinguidos dos dados do AVIRIS-NG o mineral melanterita e seu produto de desidratação rozenita. O estudo fornece novas informações sobre a distribuição superficial de minerais de ferro secundário de importância ambiental no distrito de mineração de Rio Tinto, no sudoeste da Espanha. Os resultados do mapeamento produzidos pela análise dos dados do AVIRIS-NG podem ser úteis para os estudos ambientais relacionados com a poluição por drenagem ácida de mina da rede fluvial da área

Pyrite ore cargo spills as a source of soil pollution and ecological risk along the abandoned railway corridors of the Tharsis and Rio Tinto mines (Spain).

Abandoned mining railways are a prominent legacy environmental issue facing many metalliferous regions with a long mining history. However, there is a general lack of information on potentially hazardous trace elements occurring in soils alongside railroad lines as a result of hazmat cargo spills. This paper explores for the first time the effects of pyrite ore transportation on soil pollution along the old railways of Tharsis and Rio Tinto, two historical mining districts of world-class importance in the Iberian Pyrite Belt. The railroad-side topsoil was found to be extremely acidic in reaction and contains abundant pyrite, spilled on the tracks during transit, and its oxidation products (jarosite, iron oxyhydroxides, and efflorescent sulfate minerals). Compared to local background concentrations, highly elevated levels of Pb, Zn, Cu, As, Hg, Sb, Bi, Cd, Ag, and Tl were detected in both railroad lines, indicating serious anthropogenic contamination. Exposure to soil contaminants, notably Pb, As, and Tl, could pose hazards to human health and the environment. Accordingly, a specific-site risk assessment is needed before the mining railway lines are converted into recreational trails.

Preprocessing Approach for Power Transformer Maintenance Data Mining Based on k-Nearest Neighbor Completion and Principal Component Analysis

The accuracy of a knowledge extraction algorithm in a large database depends on the quality of the data preprocessing and the methods used. The massive amounts of data that we collect every day are putting storage capacity at a premium. In reality, many databases are characterized by attributes with outliers, redundant, and even more missing values. Missing data and outliers are ubiquitous in our databases, and imputation techniques will help us mitigate their influence. To solve this problem, as well as the problem of data size, this paper proposes a data preprocessing approach based on the k-nearest neighbor (KNN) completion for imputation of missing data and principal component analysis (PCA) for processing redundant data, thus reducing the data size by generating a significant quality sample after imputation of missing and outlier data. A rigorous comparison is made between our approach and two others. The dissolved gas data from Rio Tinto Alcan’s transformer T0001 were imputed by KNN, where k equals 5. For 6 imputed gases, the average percentage error is about 2%, 17.5% after average imputation, and 23.65% after multiple imputations. For data compression, 2 axes were selected based on the elbow rule and the Kaiser threshold.

Arguments of green colonialism: a post-dialectical reading of extractivism in the Americas

ABSTRACT Through two of the largest mining companies in the world, Rio Tinto and BHP, this article traces arguments of green colonialism that use techno-determinist environmental rhetoric for extraction purposes. Contributing to environmental communication, de/coloniality studies, and Indigenous research, I argue for a more expansive approach to argument that accounts for situated knowledge, place, and affect as ontological argumentative forces. I introduce a series of case studies on Rio Tinto’s and BHP’s resource colonialisms at different sites of extraction throughout the Americas, particularly in South America, to show how “good” arguments are determined by the modern/colonial matrix power and how decolonial actors speak back. The Argumentation Network of the Americas (ANA) is in a unique position to resist argumentative logics of resource colonialism in the Americas, but argumentation must first address its own extractive models rooted in European ideals of modernism/colonialism.

RIO TINTO C355.2

Abstract Rio Tinto C355.2 is a heat-treatable, aluminum-silicon-copper-magnesium casting alloy (3xx.x series). It is available in the form of ingots for remelting, to be used for the production of sand and permanent mold castings. Alloy C355.0 is a higher purity, low iron version of alloy 355.0. Both the alloys are similar, except the lower iron in C355.0 provides better elongation and somewhat higher tensile strength. Alloy C355.0 is used in premium, high strength applications where castings are usually heat treated for maximum strength. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-490. Producer or source: Rio Tinto Limited.

Bayesian inference of multivariate-GARCH-BEKK models

The main aim of this paper is to present a Bayesian analysis of Multivariate GARCH(l, m) (M-GARCH) models including estimation of the coefficient parameters as well as the model order, by combining a set of existing MCMC algorithms in the literature. The proposed algorithm focuses on the BEKK formulation of the multivariate GARCH model. The estimation procedure will be designed as a custom MCMC with embedded Reversible Jump MCMC (RJMCMC) and Delayed Rejection Metropolis-Hastings (DRMH) steps implemented using the statistical software R. The RJMCMC steps allow three variants of BEKK models (constant, diagonal and full) to be indexed and this index included as a parameter to be estimated. The proposed MCMC algorithms are validated using extensive simulation experiments followed by a case study using bivariate data derived from the daily share prices for BHP Group Limited, Rio Tinto Group, and Fortescue Metals Group Limited on the ASX over from September 2013 to December 2021.

Potential Applications of an Exopolysaccharide Produced by Bacillus xiamenensis RT6 Isolated from an Acidic Environment.

The Bacillus xiamenensis RT6 strain was isolated and identified by morphological, biochemical and molecular tests from an extreme acidic environment, Rio Tinto (Huelva). Optimisation tests for exopolysaccharide (EPS) production in different culture media determined that the best medium was a minimal medium with glucose as the only carbon source. The exopolymer (EPSt) produced by the strain was isolated and characterised using different techniques (GC-MS, HPLC/MSMS, ATR-FTIR, TGA, DSC). The molecular weight of EPSt was estimated. The results showed that the average molecular weight of EPSt was approximately 2.71 × 104 Da and was made up of a heteropolysaccharide composed of glucose (60%), mannose (20%) and galactose (20%). The EPSt showed antioxidant capabilities that significantly improved cell viability. Metal chelation determined that EPSt could reduce the concentration of transition metals such as iron at the highest concentrations tested. Finally, the emulsification study showed that EPSt was able to emulsify different natural polysaccharide oils, reaching up to an 80% efficiency (olive and sesame oil), and was a good candidate for the substitution of the most polluting emulsifiers. The EPSt was found to be suitable for pharmaceutical and industrial applications.

Geology, Geochemistry, and Geochronology of the Giant Rio Tinto VMS Deposit, Iberian Pyrite Belt, Spain

Abstract The Rio Tinto deposit is a giant volcanogenic massive sulfide deposit (VMS) that contains more than 500 Mt of pyrite-rich massive sulfides and more than 2 Gt of mineralized stockwork. Three broad lithostratigraphic groups occur in the regional stratigraphy: the phyllite-quartzite group, the volcano-sedimentary complex, and the Baixo Alentejo Flysch Group. These three major packages reflect the evolution of a depositional environment from a stable platform to deposition in pull-apart continental basins during oblique subduction and collision and coeval synorogenic flysch sequence. The volcano-sedimentary complex, which hosts massive sulfide mineralization at Rio Tinto, can be divided into four major units: (1) the Mafic Siliciclastic Unit, (2) the Lower Sedimentary Unit, (3) the Felsic Unit, and (4) the Upper Sedimentary Unit. The Felsic Unit is further subdivided based on new U-Pb zircon geochronology into three distinct subunits. Felsic Unit I (ca. 356 Ma) includes dome complexes dominated by rhyodacite and reflects the onset of felsic magmatism in the region. Felsic Unit II (ca. 352–348 Ma) represents the main interval of volcanic activity, also dominated by rhyodacite domes and related aprons, and is associated with widespread VMS mineralization. Felsic Unit III (ca. 340 Ma) reflects a late pulse of rhyolitic volcanism. Massive sulfides occur as two different styles of mineralization: (1) replacive ores as discordant pipes hosted by glass-rich felsic rocks and enclosed by a large zone of stockwork-like mineralization and (2) overlying shale-hosted exhalative mineralization in small anoxic basins, probably formed during the collapse of the volcanic domes of Felsic Unit II in the Middle-Late Tournaisian. New lithogeochemical data illustrate two types of mafic rocks in the Mafic Siliciclastic Unit: a basaltic andesite and a high–Ti-Zr basalt, both of tholeiitic affinity. Using immobile element ratios (heavy rare earth elements [HREEs], Al, Y, Zr, and Ti) of the Felsic Unit, fundamental differences have been recognized between the subunits. The unmineralized Felsic Unit I is characterized by high Zr content (225–300 ppm) and a pronounced Eu negative anomaly, and probably represents the most fractionated rocks. Felsic Unit II is characterized by Zr values between 50 and 200 ppm. The low Zr values of the mineralized unit contrast with the typically high Zr values of the felsic rocks related to volcanogenic massive sulfides elsewhere and, at a regional scale, can help to discriminate potentially fertile domes from barren volcanism.

The Juukan Gorge destruction: a case study in stakeholder-driven and shared values approach to cultural heritage protection

PurposeIn 2020, mining activity by Rio Tinto destroyed rock caves in Western Australia's Juukan Gorge that are considered sacred sites by the First Nation Peoples of that area, the Puutu Kunti Kurrama and Pinikura (PKKP) Peoples. This paper examines the public response to the damage caused at this culturally sensitive site and identifies cultural heritage protection strategies that emerged in the aftermath of this catastrophic event.Design/methodology/approachThis research applies a qualitative case study method and analysis of open-sourced official policy documents, media reports and published institutional statements.FindingsThe research identified specific cultural heritage protection strategies, including stakeholder-driven advocacy and shared values approach to business practices to help foster a greater appreciation of the connections between people, objects and lands. Whilst the mining activities were considered lawful, significant gaps in the legislation to protect heritage sites were also exposed.Originality/valueUsing a recent case that occurred in 2020, this paper unpacks how the motivations for accessing minerals can override cultural sensibilities and legal/ethical frameworks established to protect cultural heritage. This paper brings to light the liabilities associated with the mining industry when operating in a culturally significant environment where appropriate due diligence to manage cultural heritage is not thoroughly applied. The paper highlights the role the community can play in demanding improved corporate social responsibility which can, in turn, act as a strategy for cultural heritage protection.

The use of baited stygofauna traps as a complimentary sampling method for sampling groundwater bores in the Pilbara, Western Australia

Stygofauna sampling predominantly comprises active sampling methods, such as net hauling or hand netting, which although highly effective at collecting specimens, can cause significant specimen damage and is unlikely to collect vagrant species. Studies assessing the efficacy of using stygofauna traps (both baited and unbaited) have been conducted with varying levels of success. Thus, the development of a robust and effective stygofauna trap design may be advantageous. Between 2021 and 2022, in conjunction with Rio Tinto, Biologic began developing and trialling a stygofauna trap designed to sample groundwater bores or drill holes intersecting groundwater, with the aim of evaluating the following hypotheses: The stygofauna trap design and method used would successfully collect stygofauna in groundwater bores and drill holes intersecting groundwater. Some taxa collected in stygofauna traps may differ from those collected in net haul samples, due to differences in ecological habit of fauna (crawling taxa colonising traps) or vagrant stygofauna (fauna travelling between suitable habitats). Specimens collected in traps will be in better condition than those collected in net haul samples. This has positive implications for taxonomic and molecular identification, as well as the collection of voucher specimens. The stygofauna trap design and method used would successfully collect stygofauna in groundwater bores and drill holes intersecting groundwater. Some taxa collected in stygofauna traps may differ from those collected in net haul samples, due to differences in ecological habit of fauna (crawling taxa colonising traps) or vagrant stygofauna (fauna travelling between suitable habitats). Specimens collected in traps will be in better condition than those collected in net haul samples. This has positive implications for taxonomic and molecular identification, as well as the collection of voucher specimens. Based on a fish funnel or box trap, the stygofauna traps consist of a 90mm cylindrical PVC frame, with a 150µm mesh inner lining. Both ends of the trap are capped with a removable funnel, allowing fauna to enter. In September 2021, a preliminary trial was conducted on sites intersecting the Robe and Bungaroo aquifers, in the coastal Pilbara region of Western Australia. These shallow aquifers are characterised by a highly abundant and rich stygofauna assemblage, typically dominated by crustaceans. Stygofauna traps (one trap per site) were deployed in seven groundwater bores or drill holes intersecting groundwater. The traps, baited with algae pellets, were set at the bottom of the bore, and collected between 12 and 24 hours of deployment. For comparison, net haul sampling was conducted at each site immediately prior to trap deployment. Results from the initial trial were promising, prompting a two season (wet and dry) study. This study commenced in March 2022, where traps were deployed in 11 sites across both aquifers. Two baited traps per site were deployed, one within 1m of the groundwater level and one at the end of the hole, for 72 hours, to determine if a longer deployment and an additional trap would yield better results. The final phase of sampling is planned for August 2022. Results from both the preliminary trial and first (wet) season of the 2022 study were very promising, with stygobitic taxa collected in four (of the seven) and nine (of eleven) trap sites respectively. The traps recorded a rich assemblage of stygofauna comprising Amphipoda, Copepoda, Gastropoda, Isopoda, Ostracoda and Thermosbaenacea. Compared to the respective net haul samples, the stygofauna traps yielded lower abundances and taxa richness. However, specimens collected in traps were in excellent morphological condition. At the conclusion of this study, taxonomic composition and abundance of stygofauna from the traps and net hauls will be analysed to provide further contextualisation of results.

Can the Karaman-Chappuis method significantly enhance understanding of stygofauna ecology?

Comprehensive surveys on subterranean fauna are an emerging need for assessing species diversity patterns and for developing biodiversity conservation strategies considering anthropogenic changes to the environment (e.g., mineral and water extraction, climate change). Subterranean habitats comprise mainly terrestrial and aquatic aspects of caves and fissures, as well as interstitial waters. Sampling stygofauna in Northern Western Australia is different to other parts of the world due to the predominance of meso- and micro-caverns, and thus methods are largely constrained to net hauling or pumping of either drill holes or bores installed for mineral or groundwater exploration. Water is also encountered at shallower depths beneath water courses (the interstitial or hyporheic zone) and although it is known to share fauna with subterranean systems, is largely excluded in stygofauna studies. Interstitial fauna can be sampled with the well-known Karaman-Chappuis (KC) method, which involves digging a hole in saturated alluvial deposits, letting interstitial water accumulate, and use of a scoop net to collect invertebrates. However, the application of the KC as a standard complementary method for stygofauna surveys has to date been largely unexplored. In collaboration with Rio Tinto, we included the KC method alongside traditional subterranean fauna sampling at five study areas in the Hamersley Range of Pilbara region, Western Australia. We aimed to determine its utility to better understand the ecology of subterranean fauna recorded, and therefore improve conservation outcomes. Here, we summarise the faunal groups collected using the KC method (43 samples) from surveys conducted between 2016 and 2019. We found that the stygofaunal groups more frequently collected by the KC method were Ostracoda (30.4%), Cyclopoida (28.0%), Haplotaxida (12.5%) and Amphipoda (10.7%), but other groups – Harpacticoida, Syncarida, Aphanoneura, Isopoda, Enchytraeida and Trombidiformes – were also collected in lower frequency (total of 4.9% of the records). Notably, the KC method also collected troglofaunal groups as by catch. Pauropoda (28.1%), Symphyla (21.9%), Hemiptera (12.5%), Diplura (12.5%), Zygentoma (9.4%) and Chilopoda (6.3%) were the groups most frequently collected using the KC method, but Isopoda, Palpigradi and Polyxenida were also recorded (total of 9.3% of the records). Additionally, for one project where low level taxonomic data was available (based on morphological and molecular identification), we also assessed differences in species composition of stygofauna sampled with the KC method (10 samples) compared to the traditional haul net sampling method (139 samples). We found significant differences in stygofauna species composition between the KC and haul net methods, with 13 species (out of 78 species) collected exclusively with the KC method. However, there was also a considerable overlap of species collected by the two methods (11 species). Despite the current limited data, our findings demonstrate that the KC method could be complementary to traditional stygofauna sampling methods. It also allows sampling of potentially connected groundwater habitats to occur beyond the areas drilled for minerals or water. While this method usually targets stygofauna, the collection of troglofauna as by catch is significant and provides a potential way to evaluate the ecology of troglobitic taxa. Further study is needed to assess the KC method as a valuable addition to sampling methods aiming to produce comprehensive inventories of stygofauna that integrate species found in interstitial subterranean environments.

When foreign direct investment is threatened: Rio Tinto and Richards Bay Minerals

Theoretical basis The theoretical basis of the teaching note is grounded in theory associated with macroeconomics and foreign direct investment (FDI); in particular why FDI is important to a developing country. Research methodology A secondary research methodology was used for the research and writing of this case study. Data (news articles and relevant readings) was obtained via the internet. Case overview/synopsis The case highlights the interrelated factors (civil society infrastructure, local and political unrest and community instability) that led to global mining company Rio Tinto announcing the halt of its operations and force majeure at its only South African business, Richards Bay Minerals (RBM). RBM was the largest business and employer in the province. Following the destruction of some of its equipment, civil unrest such as blocking of roads and intimidation of staff and the murder of one of their executives, Nico Swart, RBM management consequently announced all supplier contracts and operations would be halted until it was safe for work to be resumed.The case allows students to consider the interrelated factors that multinationals operating in developing countries are subject to in terms of different sub-national institutions and the potential impact of a large multinational ceasing operations in a local economy, both directly and indirectly. It concludes with considerations of what needs to be in place for RBM to continue operations. Complexity academic level This case can be used in undergraduate- and graduate-level courses, in management development programs or in short executive education courses focusing on the environment of business, macroeconomics and FDI.

Metallurgical testing and CFD simulation of StackCell® SC-50 high-intensity flotation machine

An extensive field test was conducted by Rio Tinto and Eriez to evaluate the operability and metallurgical performance of a StackCell® SC-50 high-intensity flotation machine for recovery of copper and molybdenum from flotation tailings. The field test of the 15-m 3 StackCell flotation cell was conducted at Rio Tinto’s state-of-the-art tailings recovery demonstration plant located within Kennecott Utah Copper’s tailings facility. The metallurgical results demonstrate that the StackCell technology provides a unique solution for recovering metal values from tailings, with excellent selectivity and an order of magnitude increase in flotation kinetics compared to conventional mechanical flotation machines. The metallurgical advantages of the StackCell are particularly pronounced for treating fine tailings, with upgrade ratios >25 achieved at average copper and molybdenum recoveries of 20% and 28%, respectively, within approximately one minute of flotation residence time. Computational fluid dynamics (CFD) simulations were conducted to provide a fundamental explanation of the findings from metallurgical field measurements. The simulations show that maximum levels of turbulent dissipation rates in the StackCell contacting chamber are nearly 5 times that of rotor/stator mechanisms in conventional mechanical flotation machines. Furthermore, the high levels of turbulent dissipation rates in the contacting chamber are favorable for high collisions and attachments rates of fine particles with air bubbles.