Cobalt Minerals Research Articles

Identifying Challenges and Methods for Mitigation in No-Cobalt LiNiO2 Cathode Materials

Cathode materials such as layered oxides play a crucial role in determining the energy density and safety of lithium ion batteries. LiCoO2 based cathode materials, which have been dominating the batteries in portable devices for many years, are facing unique issues, such as high cost and child labor problems in cobalt mining. As an alternative solution, LiNiO2, isostructural to the commercial LiCoO2, extensively explored in the 1990s, has recently attracted renewed attention in quest of extremely low-Co or completely Co-free layered cathodes to reduce the reliance on high-cost toxic Co resource. However, with the high nickel content, the issues such as phase transformations, anisotropically periodic volume changes, highly reactive surfaces, oxygen release, and poor thermal stability have become pronounced. These challenges, associated with the unstable bulk and surface chemistry, have hindered the implementation of LiNiO2 in practical batteries over the last few decades. In this presentation, we will present the multiscale doping strategies in LiNiO2 to improve the electrochemical performance through bulk and surface stabilizer. We will also elaborate our approach to engineer the dopant distribution in individual battery particles. In addition, we systematically investigate how the surface chemistry of LiNiO2 based materials changes with various environments, including human exhalation, sample storage, sample preparation, electrochemical cycling, and surface doping. Our results demonstrate that the surface of these materials is highly reactive and prone to alter at various stages of sample handling and characterizations. We highlight that more efforts should be devoted towards the development of highly stable CEIs either by cathode surface coating, doping, electrolyte modification or combining multiple strategies.

Incidence of low birth weight and proximity to mining in Lubumbashi and Kipushi, DR Congo

Background. Previous studies have shown high exposure to trace metals in people living close to mining/smelters in Katanga. We determined the incidence of low birth weights (LBW) in Lubumbashi and Kipushi, cities that host zones with different degrees of environmental pollution caused by copper and cobalt mining and smelting.Methods. We used routinely collected birth data in 8 out of 12 existing health zones during one year (1 July 2018 to 30 June 2019). We compared the proportions of neonates with LBW according to the presence of mining/smelting in the health zones. We also looked in more detail into the data of 9 selected maternities where we only considered first-born neonates.Results. Of 202,028 births in Lubumbashi during the observation period, 145,512 (72%) were recorded in the studied health zones, of which 11,448 were LBW neonates (excluding premature births), i.e. 7.87/100 births. The incidence of LBW was 1.80 times higher (p<0.001) for the 3 health zones with mining (6,190/57,597 births; 10.75/100) than for the 5 health zones without mining (5,258/87,915 births; 5.98/100). In the 9 selected maternities, LBWs were recorded in 589/7,203 first-born neonates (8.18/100). The incidence was 2.75 times more frequent (p<0.001) for the 2 maternities very close (i.e. within sight) to mining (235/1,400 births; 16.78/100) than for the 7 maternities far from mining (354/5,803; 6.10/100).Conclusions. Based on the previous findings of high exposure to trace metals in people living close to mining, it is plausible that mining-related metal pollution plays a role in the spatial association observed in Lubumbashi between proximity to mining and the incidence of low birth weights.

For a good selfie. Enhancing mobile phone recycling through simulated exposure to cobalt mining

Mobile phones and other electronic equipment need elements like cobalt that are obtained with enormous tolls of human rights and environmental health. In the Democratic Republic of Congo cobalt mining involves child labour. The principles of R-framework like refusing to buy and recycling post-first-life mobiles help to improve the sustainability of this and other minerals through waste management; however, current rates of mobile phone recycling are very low. Here we have designed an intervention for educational settings. We exposed students of different ages (271 of secondary and 266 of higher education) to the situation of child miners through an intervention called For a Good Selfie . Participants put themselves in the place of children working in cobalt mines. Significant increase of the intention of refusing-to-buy (between 11.6% and 45.5%) and recycling behaviour were found in students of different ages and disciplines after playing For a Good Selfie . Role-play was significantly more efficient than non-role play interventions; the first one involves a higher psychological proximity with child miners. Higher rates of recycling were found in engineering (57.7%) than in social sciences (9.6%) students. Interventions based on role-playing could be recommended for improving sustainable behaviours in the sector of mobile phones.

The Dark Side of Batteries: Education, Fertility and Cobalt Mining in the Democratic Republic of Congo

This paper provides evidence that the adoption of modern lithium-ion batteries led to a decline in child education in the Democratic Republic of the Congo. In contrast with any other mining activities, I find that the rapid increase in the worldwide demand for cobalt led to a reduction in the completed years of schooling of Congolese individuals who, at the time of the boom, were between 6 and 14 years old and lived in cobalt-rich areas. I obtain these results by exploiting exogenous geographic variation of cobalt deposits before the boom of modern electric batteries and using individual education attainment data. The estimates are robust to spatial spillover effects and selective migration.

Dispossessed by decarbonisation: Reducing vulnerability, injustice, and inequality in the lived experience of low-carbon pathways

• Links four decarbonisation pathways to negative impacts and injustices within communities across Africa and Europe. • Shows how these transitions exacerbate vulnerability and inequality. • Research and policy communities need to account for, and seek to minimize, a broader range of injustices. • Sustainability transitions and decarbonisation pathways must become more egalitarian, fair, and just. This study examines the justice and equity implications of four low-carbon transitions, and it reveals the “lived experiences” of decarbonisation as manifested across Africa and Europe. Based on extensive, original mixed methods empirical research – including expert interviews, focus groups, internet forums, community interviews, and extended site visits and naturalistic observation – it asks: How are four specific decarbonisation pathways linked to negative impacts within specific communities? Relatedly, what vulnerabilities do these transitions exacerbate in these communities? Lastly, how can such vulnerabilities be better addressed with policy? The paper documents a troublesome cohabitation between French wineries and nuclear power, the negative effects on labor groups and workers in Eastern Germany by a transition to solar energy, the stark embodied externalities in electronic waste (e-waste) flows from smart meters accumulating in Ghana, and the precarious exploitation of children involved in cobalt mining for electric vehicle batteries in the Democratic Republic of the Congo. The aims and objectives of the study are threefold: (1) to showcase how four very different vulnerable communities have been affected by the negative impacts of decarbonisation; (2) to reveal tensions and tradeoffs between European transitions and local and global justice concerns; and (3) to inform energy and climate policy. In identifying these objectives, our goal is not to stop or slow down all low-carbon transitions. Rather, the study suggests that the research and policy communities ought to account for, and seek to minimize, a broader range of social and environmental sustainability risks. Sustainability transitions and decarbonisation pathways must become more egalitarian, fair, and just.

Regional and local controls on Archean rock-hosted cobalt mineralization at the McAra deposit, southern Superior Province, Ontario, Canada

The McAra deposit is in eastern Ontario, Canada, and is hosted in an Archean inlier to the Paleoproterozoic Huronian basin. It is currently estimated to contain ∼2.4 million pounds of cobalt at an average grade of 1.25%. New drill data show the mineralized zone comprises glaucodot–cobaltite veins and breccias that transect a mafic–siliciclastic volcanogenic massive sulfide (VMS) deposit. The high cobalt grade and host stratigraphy at the McAra deposit contrast with five-element (Ag–Co–Ni–Bi–As) deposits at the Cobalt and Gowganda camps in the region that produced high-grade silver and by-product cobalt from veins spatially associated with Nipissing Gabbro intrusions. However, geochemical data from recent core samples alongside fluid inclusion and mineralogical data suggest the cobalt zone at McAra and the five-element veins share a similar metal assemblage and were deposited from similar fluids. The mafic–siliciclastic VMS deposit at McAra contains anomalous amounts of cobalt, suggesting the Archean host stratigraphy was the source for the high-grade cobalt zone. Basin brines in the Paleoproterozoic are interpreted to have leached cobalt from Archean rocks and then redeposited it through oxidation–reduction reactions along synvolcanic faults that controlled earlier VMS deposit formation. High-resolution aeromagnetic data show that McAra is immediately adjacent to a mafic dike that transects the Huronian basin along a northwest-striking, crustal-scale fault system. These data, alongside observations from field mapping, also suggest the deposit is on the margin of a sub-basin that contains an 80 km2 Nipissing sill that may have originally overlain the deposit area and been a hydrologic seal during mineralization. The new deposit- and regional-scale data and interpretations are used to create a model for the McAra deposit and provide evidence for why it is cobalt-rich relative to other five-element veins. The model and data can be used to guide exploration for additional cobalt-rich deposits in the region and similar settings globally.

Bioleaching of arsenic-rich cobalt mineral resources, and evidence for concurrent biomineralisation of scorodite during oxidative bio-processing of skutterudite

Experiments were carried out to test the amenabilities of mineral deposits that contained cobalt deported in arseno-sulfide (cobaltite) and arsenide (skutterudite) minerals, to oxidative bioleaching at mesophilic temperatures and low pH. An ore sample from the Iron Mask deposit (Canada) and a mineral concentrate from a working mine (Bou Azzer, Morocco) were thoroughly characterised, both prior to and following bio-processing. A “top down” approach, using microbial consortia including (initially) 13 species of mineral-degrading acidophiles was used to bioleach the ore and concentrate in shake flasks and bioreactors. Cobalt was successfully liberated from both materials tested (up to 93% from the ore, and 49% from the concentrate), though the chemistries of the leach liquors were very different, with redox potentials being >200 mV lower, and concentrations of soluble arsenic about 7-fold greater, with the concentrate. Addition of pyrite to the arsenide concentrate was found to promote the biomineralisation of scorodite (ferric arsenate), which was detected by both XRD and SEM-EDX, but was not found in bioleached residues of the arseno-sulfide ore. A model was proposed wherein pyrite had three critical roles in facilitating the genesis of scorodite: (i) providing the catalytic surface to promote the oxidation of As (III) to As (V); (ii) acting as a putative “seed” for scorodite crystallisation; (iii) being a secondary source of iron, since the molar ratios of iron:arsenic in the concentrate itself (0.19:1) was well below that required for effective removal of soluble arsenic as scorodite (1:1). This work provided proof of concept that cobalt arseno-sulfide and arsenide ores and concentrates are amenable to bio-processing, and also that it is possible to induce concurrent solubilisation of arsenic from primary minerals and immobilisation in a secondary mineral, scorodite.

Potential of urban cobalt mines in China: An estimation of dynamic material flow from 2007 to 2016

The development of clean energy and high-tech materials is prospering. Cobalt, an indispensable material in this process, has drawn attention worldwide. China has a high demand for cobalt; the uncertainty of raw material supply and increasing domestic demand for cobalt may trigger a severe cobalt crisis in China. Thus, increasing urban mining may be essential for securing cobalt. This study analysed the changes in China's in-use stock of cobalt over 10 years using dynamic material flow analysis. We modelled the material flow cycle of China's cobalt in 2007–2016. Scenario analysis was conducted to estimate the potential of urban cobalt mines in China in 2007–2016, considering the final cobalt-bearing product lifespan distributions; the recycling rate of cobalt waste; and ideal (A1, A2), intermediate (B1, B2, C1, C2) and poor (D1, D2) scenarios. In 2007–2016, China's in-use stock of cobalt reached 115,100 tons (68.45% from batteries and 15.24% from superalloys). In the eight scenarios, the potential of China's urban cobalt mines was 78,800–186,500 tons. China's urban cobalt mines have great potential, but the actual exploitable volume is low, mainly due to the low overall recycling efficiency of domestic cobalt waste, e.g., the recycling rate of waste lithium-ion batteries is less than 10%. A frame of influencing factors for cobalt recycling was proposed, and the actual exploitable volume of China's urban cobalt mines in 2007–2016 was evaluated to be 30,700–60,700 tons. Policymakers should introduce effective policies to encourage cobalt recycling and increase awareness of recycling in the long run.

Mineralogical Prediction of Flotation Performance for a Sediment-Hosted Copper–Cobalt Sulphide Ore

As part of a study investigating the influence of mineralogical variability in a sediment hosted copper–cobalt deposit in the Democratic Republic of Congo on flotation performance, the flotation of nine sulphide ore samples was investigated through laboratory batch kinetics tests and quantitative mineral analyses. Using a range of ore samples from the same deposit the influence of mineralogy on flotation performance was studied. Characterisation of the samples through QEMSCAN showed that bornite, chalcopyrite, chalcocite and carrollite are the main copper-bearing sulphide minerals while carrollite is the only cobalt-bearing mineral. Mineralogical characteristics were averaged per sample to allow for a quantitative correlation with flotation performance parameters. Equilibrium recoveries, rate constants and final grades of the samples were correlated to the feed mineralogy through Multiple Linear Regression (MLR). Target sulphide minerals content and particle size, magnesiochlorite content, carrollite liberation and association of the copper and cobalt minerals with magnesiochlorite and dolomite were used to predict flotation performance. Leave One Out Cross Validation (LOOCV) revealed that the final copper and cobalt grades are predicted with an R2 of 0.80 and 0.93 and Root Mean Square Error of Cross Validation (RMSECV) of 4.41% and 1.34%. The recovery of cobalt and copper with time can be predicted with an R2 of 0.94 for both and an overall test error of 4.70% and 5.14%. Overall, it was shown that quantitative understanding of changes in mineralogy allows for prediction of changes in flotation performance.

Minerals of the Fe–Ni–Co–Cu–S System in Picrite Intrusions of the Southern Urals: Signatures of Liquation and Differentiation of the Sulfide Melt

New data on the minerals of the Fe–Ni–Co–Cu–S system in the differentiated intrusions of the Southern Urals are presented. Based on a detailed study of parageneses and associations of sulfide minerals, it was revealed that nickel enters the composition of two early formed phases (olivine and pentlandite) during melt differentiation, which leads to nickel “deficiency” and crystallization of cobalt (Co-bearing) minerals in late differentiates of the sulfide melt associated with gabbroids. Liquation isolations found in the rocks of the Misaelga complex, composed of unidentified phases, as well as the studied paragenetic intergrowths/exsolution structures, indicate that the sulfide melt had a multicomponent (Fe, Ni, Co, Cu, Zn) composition, crystallization of which in the local volume led to the formation of “intermediate” phases. It is shown that the onset of sulfide formation in the rocks of the Misaelga complex was realized in a magma chamber.

Blockchain for Supply Chain Traceability: Business Requirements and Critical Success Factors

We seek to guide operations management (OM) research on the implementation of supply chain traceability systems by identifying business requirements and the factors critical to successful implementation. We first motivate the need for implementing traceability systems in two very different industries—cobalt mining and pharmaceuticals—and present business requirements and critical success factors for implementation. Next, we describe how we carried out thematic analysis of practitioner and scholarly articles on implementing blockchain for supply chain traceability. Finally, we present our results pertaining to the needs of different stakeholders such as suppliers, consumers, and regulators. The business requirements for traceability systems are curbing illegal practices; improving sustainability performance; increasing operational efficiency; enhancing supply‐chain coordination; and sensing market trends. Critical success factors for implementation are companies’ capabilities; collaboration; technology maturity; supply chain practices; leadership; and governance of the traceability efforts. These findings provide a nascent measurement model for empirical work and a foundation for descriptive and normative research on blockchain applications for supply chain traceability.

Закономерности изменения нетрадиционных термодинамических функции ΔrG0/n и ΔfG0(среднее) для минералов кобальта

This article considers general principle of predicting the difference in the reactivity of minerals and solvents in the conditions of their interaction at the interface between solid and liquid for cobalt minerals in the processing of mineral raw materials. The ideas of new properties of chemical affinity which allowed to carry out the forecast of a choice of efficiency of action of the dissolving reagent for opening of hardly soluble minerals of cobalt and the forecast of consecutive passing of the competing reaction proceeding on solid-liquid boundary at processing of mineral raw materials by a hydrochemical method at the level of an electron are stated. Previously unknown pattern of change the effectiveness of the solvent of the reagents and the sequence of passing a competing reaction was established, namely, that the effectiveness of the solvent of the reagent and the sequence of passing the subsequent reaction naturally varies with the calculated values given new chemical affinity (DrG0/n). It is practically proposed to use the average atomic energy of the formation of solids ΔfG0(averaged) and calculated value of the new chemical affinity DrG0/n to create scientific basis for the opening of cobalt minerals contained in the mineral raw materials with the least time.

Identifying supply risks by mapping the cobalt supply chain

Cobalt is considered a critical raw material. Global cobalt demand is expected to quadruple in the next four decades, due primarily to lithium-ion battery demand. Uniquely, this study provides detailed geographically explicit data on the cobalt supply chain, with the aim of both determining how susceptible primary cobalt production is to supply chain disruptions, and to evaluate possible supply risks. We conclude that the risks for supply chain disruptions are high. Firstly, the cobalt market is highly concentrated, with more than half of the cobalt mined in the Democratic Republic of the Congo, and almost half of the cobalt refined in China. Secondly, almost all cobalt is mined as a by-product of copper and nickel. Finally, political stability in production countries is considered to be medium to very weak. There are also several factors in play that reduce supply risks. The concentration of the individual mines, refineries and companies remains under the threshold of a concentrated market, and the estimated 80 artisanal cobalt mines further diversify the mined supply. A network analysis shows the important position of companies with high betweenness and degree centrality. A disruption at these companies can affect the functioning of the overall supply chain. The geographic and a network visualization provide useful insights in the supply risks. Based on the analysis, we recommend to diversify cobalt production, through the development of mines, refineries, and efforts to ensure socially and environmentally sustainable artisanal mining.

Extraction of Cobalt and Iron from Refractory Co-Bearing Sulfur Concentrate

In this study, oxidizing roasting, segregation roasting, and magnetic separation are used to extract cobalt and iron from refractory Co-bearing sulfur concentrate. The Co-bearing sulfur concentrate containing 0.68% Co, 33.26% Fe, and 36.58% S was obtained from V-Ti magnetite in the Panxi area of China by flotation. Cobalt pyrite and linneite were the Co-bearing minerals, and the gangue minerals were mica, chlorite, feldspar, and calcite in Co-bearing sulfur concentrate. The results show that cobalt is transformed from Co-pyrite and linneite to a Co2FeO4-dominated new cobalt mineral phase, and iron is transformed from pyrite to Fe2O3 and an Fe3O4-dominated new iron mineral phase after oxidizing roasting. Cobalt changed from CoFe2O4 to a new cobalt mineral phase dominated by [Co] Fe solid solution, and iron changed from Fe2O3 to a new iron mineral phase dominated by metal Fe and Fe3O4 after segregation roasting. Cobalt concentrate with a cobalt grade of 15.15%, iron content of 71.22%, and cobalt recovery of 90.81% as well as iron concentrate with iron grade of 60.06%, cobalt content of 0.11%, and iron recovery of 76.23% are obtained. The main minerals in the cobalt concentrate are Fe, [Co]Fe, Fe3O4, and SiO2, and the main minerals in the iron concentrate are Fe3O4, FeO, Ca2Si2O4, and Ca2Al2O4.

The decarbonisation divide: Contextualizing landscapes of low-carbon exploitation and toxicity in Africa

Much academic research on low-carbon transitions focuses on the diffusion or use of innovations such as electric vehicles or solar panels, but overlooks or obscures downstream and upstream processes, such as mining or waste flows. Yet it is at these two extremes where emerging low-carbon transitions in mobility and electricity are effectively implicated in toxic pollution, biodiversity loss, exacerbation of gender inequality, exploitation of child labor, and the subjugation of ethnic minorities. We conceptualize these processes as part of an emerging “decarbonisation divide.” To illustrate this divide with clear insights for political ecology, sustainability transitions, and energy justice research, this study draws from extensive fieldwork examining cobalt mining in the Democratic Republic of the Congo (DRC), and the processing and recycling of electronic waste in Ghana. It utilizes original data from 34 semi-structured research interviews with experts and 69 community interviews with artisanal cobalt miners, e-waste scrapyard workers, and other stakeholders, as well as 50 site visits. These visits included 30 industrial and artisanal cobalt mines in the DRC, as well as associated infrastructure such as trading depots and processing centers, and 20 visits to the Agbogbloshie scrapyard and neighborhood alongside local waste collection sites, electrical repair shops, recycling centers, and community e-waste dumps in Ghana. The study proposes a concerted set of policy recommendations for how to better address issues of exploitation and toxicity, suggestions that go beyond the often-touted solutions of formalisation or financing. Ultimately, the study holds that we must all, as researchers, planners, and citizens, broaden the criteria and analytical parameters we use to evaluate the sustainability of low-carbon transitions.

Use of Taguchi’s DOE for process optimization of Co(II) extraction in chloride medium by Aliquat 336

Taguchi’s framework for the design of experiments (DOE)—more specifically, the orthogonal array L4 (23)—was used to optimize the extraction process of Co(II) statistically. A series of experiments involving the liquid–liquid extraction of cobalt by the ionic liquid extractant Aliquat 336 in a hydrochloric acidic medium were conducted. One experimental parameter was optimized per experiment. The cobalt was extracted (efficiency: 62%) and pre-concentrated (efficiency: 41%) from the loaded organic phase in deionized water (the stripping solution). Application of the McCabe–Thiele method indicated that six theoretical stages were needed to recover 98% of the cobalt. Process optimization was then performed via statistical analysis of the experimental data. Analyses of variance and of means showed that uncontrollable factors (noise) were completely absent from the process, and that only the main effects of the controllable factors A, B, and C—with no factor interactions—contributed to the optimal extraction of the cobalt, which was achieved when A, B, and C were at levels 2, 2, and 1, respectively. In this scenario, the signal-to-noise ratios for A, B, and C were 32, 29, and 26, respectively. Factor A was found to exert the strongest influence on the Co(II) extraction efficiency (50% of the combined influence of the three factors), followed by factors B (28%) and C (22%). Taguchi’s method is a widely accepted approach to DOE, and the application of this approach in this work shows that high-quality products can be produced using ecological green solvents, thus reducing the impact of cobalt production on the environment and ecosystems, which is important given that the cobalt mining industry is expanding globally.

Degradation of α-nitroso-β-naphthol by UVA-B activated peroxide, persulfate and monopersulfate oxidants in water

Abstract Flotation reagents, especially new chelating agents represented by α-nitroso-β-naphthol, are the main components of cobalt mining drainage. This study reports the degradation of α-nitroso-β-naphthol by simulated UVA-B (280–400 nm) activated systems using three common oxidants, hydrogen peroxide, sodium persulfate and potassium monopersulfate at a laboratory scale using a photoreactor. Parameters which can affect the degradation process were investigated and comparison of the degradation performance of the three systems were made. Based on the results, UVA-B/sodium persulfate system exhibited best performance towards the removal of α-nitroso-β-naphthol with a lower cost of oxidant and energy consumption compared to the others. The removal efficiency was found to increase as the oxidant dosage and the UVA-B power increases. Only potassium monopersulfate could be activated by bicarbonate and chloride ions, and SO42− has insignificant effect on the removal efficiency of α-nitroso-β-naphthol for all systems while NO3− inhibited the degradation of α-nitroso-β-naphthol. In the UVA-B/hydrogen peroxide system, the hydroxyl radical had a leading role in the degradation of α-nitroso-β-naphthol, while in the other two systems, the degradation of α-nitroso-β-naphthol was mainly caused by the hydroxyl and sulphate radicals. Ten major intermediates from α-nitroso-β-naphthol degradation in the three oxidation systems were identified by gas chromatography and mass spectrometry. In summary, this report could be a great input in developing UVA-B activated oxidants-based treatment technologies. The UVA-B/sodium persulfate system is strongly recommended for its consideration in the treatment of mine impacted wastewaters.

Factors Controlling Hydrothermal Nickel and Cobalt Mineralization—Some Suggestions from Historical Ore Deposits in Italy

We compare three poorly known, historical Ni–Co-bearing hydrothermal deposits in different geological settings in Italy: The Ni–Co–As–Sb–Au-bearing Arburese vein system (SW Sardinia), the Co–Ni–As-rich Usseglio vein system (Piedmont), and the small Cu–Ag–Co–Ni–Pb–Te–Se stockwork at Piazza (Liguria). These deposits share various (mineralogical, chemical, thermal, and stable isotopic) similarities to the Five Element Vein-type ores but only the first two were economic for Co–Ni. The Sardinian Ni-rich veins occur in Paleozoic basement near two Variscan plutons. Like the Co-rich Usseglio vein system, the uneconomic Piazza deposit is hosted in an ophiolite setting anomalous for Co. The Sardinian and Usseglio deposits share a polyphasic assemblage with Ni–Co–As–Sb–Bi followed by Ag-base metal sulfides, in siderite-rich gangue, whereas Piazza shows As-free, Ag–Pb–Te–Se-bearing Co–Ni–Cu sulfides, in prehnite–chlorite gangue. Fluid inclusions indicated Co–Ni arsenide precipitation at ≈170 °C for Usseglio, whereas for the Sardinian system late sulfide deposition occurred within the 52–126 °C range. Ore fluids in both systems are NaCl-CaCl2-bearing basinal brines. The chlorite geothermometer at Piazza provides the range of 200–280 °C for ore deposition from CO2-poor fluids. Enrichments in Se and negative δ13C in carbonates suggest interaction with carbonaceous shales. These deposits involve issues about source rocks, controls on Co/Ni and possible role of arsenic and carbonate components towards economic mineralization.

The precarious political economy of cobalt: Balancing prosperity, poverty, and brutality in artisanal and industrial mining in the Democratic Republic of the Congo

This study examines the political economy of cobalt mining in the Democratic Republic of the Congo. There, a veritable mining boom for cobalt is underway, driven by rising global demand needed for batteries and other modern digital devices. Based on extensive and original field research—including expert interviews, community interviews with miners and traders, and naturalistic observation at 21 mines and 9 affiliated mining sites—this study asks: How is cobalt currently extracted? What benefits has cobalt mining brought communities? What risks has it created? And, critically, what policies need implemented to make mining there more equitable and sustainable? It documents six interrelated benefits to cobalt mining, including poverty reduction, community development, and regional stability, alongside six serious challenges, including accidents and occupational hazards, environmental pollution and degraded community health, and violent conflict and death. It then proposes seven policy recommendations for different stakeholder groups such as local and national government, industrial (and often foreign) mining companies, miners and their communities, and the manufacturers of electronic products using cobalt. The study primarily seeks to humanize the lived experiences of Congolese cobalt mining, and to reveal the tensions and tradeoffs associated with the recent mining boom.

Unprecedentedly High Dust Ingestion Estimates for the General Population in a Mining District of DR Congo.

The mining of metals in low income countries is often associated with high exposure to dust that contributes to metal exposure. Here, dust ingestion estimates were made from fecal excretion of inert tracers with corrections for dietary contribution. The study took place in the cobalt mining area of Lubumbashi (DR Congo) and involved 120 nonoccupationally exposed participants in the dry season, with 51 of these being repeated in the rainy season. For each participant, duplicate meals (0-96 h), feces (24-120 h), and indoor/outdoor dust (<250 μm) were collected. The dust ingestion estimates (g day-1) were derived from Nb, Ti, and V as best tracers and were 0.28 (geometric mean), 3.3 (mean), and 13 (P95); these values are almost a factor 10 above currently accepted estimates for the general population in high income countries. Mean dust ingestion in the dry season was twice that of the rainy season, and the P95s were significantly higher in children (3-15 years) than in male adults and toddlers; geophagy (>40 g day-1) was suspected in three individuals. These data explain the previously reported extreme cobalt exposures in children and support the need to manage dust in the metal mining operations.