Gold Mining Research Articles

Mercury Dynamics and Bioaccumulation Risk Assessment in Three Gold Mining-Impacted Amazon River Basins.

Mercury contamination from gold mining in the Amazon poses significant environmental and health threats to the biome and its local populations. The recent expansion of non-industrial mining areas has severely impacted territories occupied by traditional communities. To address the lack of sampling data in the region and better understand mercury dynamics, this study used the probabilistic model SERAFM to estimate the mercury distribution and bioaccumulation in fish. The analysis covered 8,259 sub-basins across three major Amazonian basins: the Branco, Tapajós and Xingu rivers. The findings revealed increasing downstream mercury levels, with notable accumulations in the main watercourses influenced by methylation processes and mining releases. The projected concentrations showed that an average of 27.47% of the sub-basins might not comply with Brazilian regulations, rising to 52.38% in the Branco and Tapajós river basins separately. The risk assessment of fish consumption based on the projections highlighted high mercury exposure levels among traditional communities, particularly indigenous populations, with an average of 49.79% facing an extremely high risk in the Branco and Tapajós river basins. This study demonstrated SERAFM's capacity to fill information gaps in the Amazon while underscoring the need for enhanced data collection, culturally sensitive interventions and regulatory updates to mitigate mercury contamination in gold mining-affected areas.

Experimental Investigation into Deploying a Wi-Fi6 Mesh System for Underground Gold and Platinum Mine Stopes

Stopes suffer from unreliable wireless communication due to their harsh environment. There is a lack of confidence within industry regarding the effectiveness of existing solutions in providing reliable high-bandwidth performance in hard rock stopes. This work proposes that Wi-Fi6 is a good candidate for reliable high-bandwidth communications in underground hard rock stopes. Experiments in a tunnel and mine stope were conducted to evaluate the performance of Wi-Fi6 in terms of latency, jitter, and throughput. Different criteria, such as multi-hop systems, varying multipath, mesh routing protocols, and frequencies at different bandwidths, were used to evaluate performance. The results show that Wi-Fi6 performance is greater in stopes compared to tunnels. Signal quality evaluations were conducted using the Asus RT-AX53U running OpenWrt, and an additional experiment was conducted on the nrf7002dk running Zephyr OS to evaluate the power consumption of Wi-Fi6 against the industry standard for low-powered wireless communications, IEEE 802.15.4. Wi-Fi6 was found to be more power-efficient than IEEE 802.15.4 for Mbps communications. These experiments highlight the signal robustness of Wi-Fi6 in stope environments and also highlights its low-powered nature. This work also highlights the performance of the two most widely used open-source mesh routing protocols for Wi-Fi.

Understanding the Perspective of the Mining-Affected Community on Illegal Gold Mining (PETI) in Gogorea Village, Waeapo District, Buru Regency

This research aims to understand the perspectives of mining communities on illegal gold mining (PETI). They conducted their study in Gogorea Village, Waeapo District, and Buru Regency, using a qualitative method with theoretical foundations to grasp community perspectives. Sampling was done through simple random sampling involving 12 respondents: Village Heads, five local miners, and six non-local miners. Data were collected through observation, interviews, and documentation, then analyzed descriptively using the Likert scale. The results reveal the unique characteristics of PETI in Gogorea Village, where miners use simple and traditional tools, often collaborate, and employ traditional gold refining methods. Although PETI provides income, its severe environmental impacts, including waste, soil, forest, and air pollution, are evident. Ecological protection is necessary for sustainability and community welfare. It is recommended to enforce strict regulations and increase monitoring of PETI activities to mitigate environmental damage. Additionally, providing sustainable economic alternatives for communities is crucial to reducing dependence on illegal mining.

Determination and contamination status of mercury and other heavy metals in artisanal and small-scale gold mining at Banyumas region, Central Java, Indonesia, using ICP-OES

ABSTRACT The determination of mercury and other heavy metals (As, Cd, Cr, Ni, and Pb) has been carried out as toxic metals for the human body. Sample preparation was carried out by the microwave digested assist. The determination of heavy metals was carried out using the ICP-OES. The validation parameters used were linearity, Limit of Detection (LoD), Limit of Quantitation (LoQ), precision, and accuracy. Mercury, Arsen, Cadmium, Chromium, Nickel, and Lead average content in sediment gold ore processing waste was 1617.64, 5525.09, 20.24, 484.96, 259.67, and 1210.27 μg/kg, respectively. Linearity used a standard solution of 10–1000 μg/kg, and it produced a regression equation with r2 > 0.9992. The Limit of Detection (LoD) and the Limit of Quantitation (LoQ) was below 1.56 μg/kg and 6.27 μg/kg, respectively. The precision was calculated by the repeatability method, with a result of %RSD below 2.30%. Accuracy was obtained by recovering a spiked standard. The recovery value was found to be between 83% and 118%. Geoaccumulation Index (Igeo), Metal Pollution Index (MPI), Degree of Contamination (Cdeg), and Potential Ecological Risk Index (PERI) in this study was −8.62–1.43, 0.02–5.33, 8.80, and 168.59, respectively. The waste processing site at Artisanal and Small-Scale Gold Mining is generally contaminated by mercury and other heavy metals. All the validation parameters of the method are in the acceptability range, so the method can be used as a routine method for determining mercury and other heavy metals (As, Cd, Cr, Ni, and Pb) levels in gold ore processing waste.

Secondary Riedel faults in the Batouri region and inferences to major shear zones kinematics and gold mineralization

Secondary Riedel faults in the Batouri region and inferences to major shear zones kinematics and gold mineralization

Investigation of Mutations in the crt-o and mdr1 Genes of Plasmodium vivax for the Molecular Surveillance of Chloroquine Resistance in Parasites from Gold Mining Areas in Roraima, Brazil.

Plasmodium vivax causes the largest malaria burden in Brazil, and chloroquine resistance poses a challenge to eliminating malaria by 2035. Illegal mining in the Roraima Yanomami Indigenous territory can lead to the introduction of resistant parasites. This study aimed to investigate mutations in the pvcrt-o and pvmdr-1 genes to determine their potential as predictors of P. vivax chloroquine-resistant phenotypes. Samples were collected in two health centers of Boa Vista. A questionnaire was completed, and blood was drawn from each patient. Then, DNA extraction, PCR, amplicon purification, and DNA sequencing were performed. After alignment with the Sal-1, the amplified fragment was analyzed. Patients infected with the mutant parasites were queried in the Surveillance Information System. Among the patients, 98% (157/164) of participants were from illegal mining areas. The pvcrt-o was sequenced in 151 samples, and the K10 insertion was identified in 13% of them. The pvmdr1 was sequenced in 80 samples, and the MYF haplotype (958M) was detected in 92% of them and the TYF was detected in 8%, while the MYL was absent. No cases of recrudescence, hospitalization, or death were found. Mutations in the pvcrt-o and pvmdr-1 genes have no potential to predict chloroquine resistance in P. vivax.

Evaluation of Mercury Exposure in Two Artisanal and Small-Scale Gold Mining Communities in Peru

Evaluation of Mercury Exposure in Two Artisanal and Small-Scale Gold Mining Communities in Peru

Eco Mining Project: Raising awareness and practicing clean technologies in Artisanal and Small-Scale Gold Mining Communities in Peru

Eco Mining Project: Raising awareness and practicing clean technologies in Artisanal and Small-Scale Gold Mining Communities in Peru

The Mystery of Black Rice: Food, Medicinal, and Spiritual Uses of Oryza glaberrima by Maroon Communities in Suriname and French Guiana

AbstractDuring plantation slavery, African rice (Oryza glaberrima Steud.) was widely cultivated in the Americas but was soon replaced by Asian rice (Oryza sativa L.). Maroons, descendants of Africans who escaped slavery in Suriname and French Guiana, continue to cultivate African rice. Genomic research linked this rice to an O. glaberrima variety in the Ivory Coast. Based on interviews with 99 Maroon farmers, of whom 23 cultivate black rice, we describe its diverse uses as (ceremonial) food, offerings, spiritual medicine, and its role during funerals. Maroon oral history accounts on the origin of black rice differ among and within communities: enslaved women brought it from Africa or took it from the plantations where they worked; escaped slaves found it in the savanna; or ancestors encountered it in interior swamps. These multiple and sometimes contradictory accounts of the origins of black rice are related to the diverse ethnic and geographical backgrounds of the Africans brought as slaves to Suriname and their different histories with the crop after marronage. Various characteristics of black rice, including its ability to compete with weeds and grow on poor soils, its shattering seeds, and its visibility to birds explain how this African domesticate survived in the wild in the Amazonian forest. The migration of Maroons to cities, their engagement in gold mining, and their evangelization may lead to the loss of black rice knowledge and practices.

“If your ox does not pull, what are you going to do?”: Persistent Violence in South Africa’s Deep-Level Gold Mines and Its Contribution to the 1922 Rand Rebellion

AbstractThe 1922 Rand Rebellion was the only instance of worker protest in the twentieth century in which a modern state used tanks and military airplanes, as well as mounted infantry, to suppress striking workers. These circumstances were unprecedented in their own time and for most of the century. The compressed and intensely violent rebellion of twenty thousand white mineworkers in South Africa’s gold mines had several overlapping features. Within a matter of days—from 6 to 12 March—it went from a general strike to a racial pogrom and insurrection against the government of Prime Minister Jan Smuts. Throughout all these twists and turns, the battle standard remained, “Workers of the world unite and fight for a White South Africa!” Race and violence were integral features of South Africa’s industrial history, but they do not explain the moments when discrete groups of people chose to use them as weapons or bargaining tools. At the close of the First World War, for instance, South Africa’s white mine workers demanded a more comprehensive distribution of the privileges of white supremacy, but in a manner that was both violent and contentious. Consequently, South Africa’s immediate postwar period became one of the most violent moments in its history.

Refold structures of the Archaean Nyanzaga gold Project, Sukumaland Greenstone Belt, Tanzania: Precursors to the gold-bearing fault system

This study presents a complete investigation into the structural-hydrothermal evolution of the Nyanzaga and Kilimani gold deposits within the Neoarchean Sukumaland Greenstone Belt, Tanzania Craton. The first compressional stage, D1a, creates upright E-W folds in response to N-S-oriented shortening. The second stage, D1b, refolds the previously formed structures during ongoing compression/transpression under N-S-oriented shortening. Due to the brittle nature of late deformation, during D1c, a set of faults emerges, with the NW-SE ones exhibit dextral shearing and control the formation of normal N-S vertical faults.A protracted hydrothermal history is recorded, beginning with a disseminated silicate minerals- and pyrite-rich, gold-barren stage associated with the D1a and D1b deformations, followed by the development of a gold-endowed vein system during progressive D1b and D1c stages. Gold was mainly concentrated within vertical NW-SE (Kilimani) and N-S (Nyanzaga) faults. Our findings challenge traditional polyphase deformation models presented in the other gold deposits of the area, by proposing a progressive and continuous deformation-hydrothermal history. In addition, we highlight the influence of refold structures on fault geometry, which is crucial in concentrating gold mineralization under continuous N-S compression and transpression.

Lithochemistry, and gold and sulphides chemistry from the Abiete-Toko Gold District in the NW edge Congo Craton, Nyong Complex (SW-Cameroon): Insights into the primary source of alluvial gold deposits and occurrence in the area

The Abiete-Toko Gold District (ATGD), in the Nyong Complex, NW edge of the Congo Craton, is one of the numerous Cameroonian mining districts producing alluvial gold. Although numerous works were focused on the ATGD alluvial gold deposits, their primary source(s) remain(s) unknown. This study combines the chemistry of pyrite and chalcopyrite which were determined by inductively coupled plasma-mass spectrometry (LA-ICP-MS), the chemistry of alluvial gold grains determined by electron probe microanalysis (EPMA), and whole rock composition determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results provide the first evidence of gold in the rocks, and its genesis is subsequently discussed. Gold in the ATGD rocks is essentially invisible and lattice bound in pyrite and chalcopyrite, which intake up to 3.11 ppm and up to 32.6 ppm Au, respectively. The gold-bearing metatexites (garnet migmatite) and ultrabasites (serpentinised peridotites) are here therefore, interpreted as possible sources of the ATGD alluvial gold deposits and occurrences. In metatexite, pyrite and chalcopyrite occur within quartz biotite veins, while in ultrabasites pyrite and chalcopyrite are disseminated grains of millimetric sizes, and ovoid or cubic shapes. Gold mineralisation is shear-hosted and, shows evidence of hydrothermal alteration (sulphidation) induced by circulating magmatic and Co-rich (0.01–1.53 %) fluids.

Deep structure of the Wulong goldfield, Liaodong Peninsula, China, revealed by receiver functions: implications for the tectonic and mineralization dynamics

During the Mesozoic, the North China Craton experienced intense tectonic movements that resulted in the formation of numerous gold deposits on the Liaodong and Jiaodong Peninsulas in northeastern China. To investigate the relationship between deep crustal structure and gold mineralization in the Liaodong Peninsula, we deployed 334 dense seismic stations in the Wulong goldfield (WLGF) with the idea of analysing numerous receiver functions at different array stations. The purpose focused on knowing the potential for gold mineralization in the area. The study revealed the following: (1) The WLGF is characterized by a crustal thickness of approximately 32 km and an average Vp/Vs ratio of 1.76. The high value of the Vp/Vs ratio near the Wulong gold deposit suggests that mantle materials have penetrated into the crust and contributed to the mineralization process. (2) A low-velocity layer located at a depth of 10–18 km below the WLGF seems to support the existence of a potentially brittle-ductile transition zone. Also, hydrothermal magma upwelling channels are observed in the upper crust beneath the Wulong gold deposit. (3) The presence of a discontinuous low-velocity layer in the middle crust beneath the Liaodong Peninsula suggests promising prospects for gold ore exploration. The receiver functions method based on a dense seismic array employed in this study can offer valuable references and guidance for the fine exploration and research of ore deposits in other regions globally.

Integrated geophysical and remote sensing investigations in hydrothermal mapping for orogenic gold mineralization in parts of Ife–Ilesa schist belt SW Nigeria—a case study

Integrated geophysical and remote sensing investigations in hydrothermal mapping for orogenic gold mineralization in parts of Ife–Ilesa schist belt SW Nigeria—a case study

Unraveling the dealloying mechanism of a Au33Fe67 metastable precursor for a low-cost nanoporous gold production

A low-cost Nanoporous Gold (NPG) has been successfully prepared by chemical dealloying of a Au33Fe67 supersaturated solid solution, whose ribbons were obtained by rapid solidification using melt-spinning technique. The dealloying procedures were carried out in 1 M HNO3 at 70 °C for varying durations. As-quenched ribbon and dealloyed samples have been structurally and compositionally investigated using XRD, FESEM and EDS techniques. The obtained NPG is homogeneous with tunable ligament size and shape, easy-to-handle and free-standing. Most notably, a metastable precursor has been favourably obtained from an immiscible Au-Fe system. Furthermore, according to the characterization results, a mechanism of dealloying has been proposed. Pairing Au with cheap and abundant Fe and fabricating an Fe-rich precursor gives an exceedingly cost-effective starting material. No usage of critical raw materials is involved. Then, employing a straight-forward and rapid dealloying procedure to obtain the NPG sample, makes for an overall inexpensive and sustainable production.

Insights into the effects of exposed facets of MoS2 on gold recovery from Au(S2O3)23- solution

MoS2 materials performed well as adsorbent for Au(S2O3)23- recovery, but the effect of its crystal facets on recovery behavior and mechanism remained unclear. In this study, flower-shaped MoS2 with exposed (110) facet and flake-shaped MoS2 with (002) exposed facet have been synthesized through a simple hydrothermal method, and their recovery performance and mechanism for gold from Au(S2O3)23- solution were explored. The results indicated that MoS2 materials could recover Au(S2O3)23- via adsorption and photocatalytic reduction. Importantly, MoS2 materials with different exposed facets displayed crystal anisotropy, which greatly affected the recovery behavior of Au(S2O3)23-. Flake-shaped MoS2 showed better dispersibility because of stronger surface electronegativity, and flower-shaped MoS2 displayed better photocatalysis property thanks to more activated edge sites. The better dispersibility made flake-shaped MoS2 have higher contact probability to Au(S2O3)23- molecules, resulting in faster recovery rate as well as higher recovery for Au(S2O3)23- with low concentration. Meanwhile, flower-shaped MoS2 with better photocatalysis property could release more photogenerated electrons, so that achieving more excellent recovery for Au(S2O3)23- with high concentration. The finding in this study enhanced the understanding about the effect of MoS2 facets on Au(S2O3)23- recovery, which had great significance for the design of MoS2 structure and green production of gold in the future.

Mercury in river samples with artisanal and small-scale gold mining influence: The case of the upper Madeira River Basin (Brazil/Bolivia)

The issue of mercury (Hg) is becoming a growing concern in the Amazon basin. The Madeira River is known for intense artisanal and small-scale gold mining (ASGM), and Hg poses a significant issue for public health and ecosystems. In this study, we analyzed Hg riverine concentrations in water samples, suspended particulate matter (SPM) and sediments in the Upper Madeira River Basin. We also examined mineralogical and elemental compositions of the solid phase to enhance our understanding of Hg behavior in the environment. Dissolved Hg was not detected in water, and Hg concentrations in solids remained in the same order of magnitude across different rivers, despite variations in gold mining intensities along their courses. Generally, Hg concentrations were higher in compartments with a greater proportion of fine sediments (clay and silt), with average concentrations of 91.4 ± 13.0, 41.6 ± 11.0, and 22.2 ± 1.6 ng g−1 for SPM (n = 14), riverbank (n = 12), and riverbed (n = 4) sediments, respectively. Multivariate analysis shows Hg chemical associations related to clay minerals and organic matter (OM) for the riverbank and SPM compartments. However, in SPM, OM had a greater influence on Hg distribution. Conversely, one riverbed sample highlights with a high Hg concentration (547.78 ng g−1), large content of heavy minerals, and a distinct geochemical signature. This sample was collected in a river section upstream of Beni River's rapids where the river's hydrodynamics can induce the high concentration of heavy minerals in this riverbed sediment. This unexpectedly high Hg concentration encountered in sediment rich in heavy minerals is likely related to contamination by Hg-rich mine tailing discarded into the river. Overall, this study discusses the issue of Hg mobility in rivers suggesting its dispersion, i) associated with fine fraction rich in clay and OM, and ii) associated with heavy minerals.

Genesis and Geochemical Prospecting Features of Gold Mineralization at the V-Shear Prospect, Gebel El Sukari Gold Mine Area, Eastern Desert, Egypt

Genesis and Geochemical Prospecting Features of Gold Mineralization at the V-Shear Prospect, Gebel El Sukari Gold Mine Area, Eastern Desert, Egypt

Iodide- and electrochemical assisted removal of mercury by Cirsium arvense from gold tailings in the Amansie West District, Ghana

Mercury (Hg) pollution in Ghana through mining has become a serious environmental challenge. This study investigates the potential of Cirsium arvense to photostabilize Hg using electrokinetic current with or without an iodide solution in gold mine tailings heavily contaminated through mining activities in southern Ghana. An initial Hg concentration of 9.60 mg/kg using cold vapor atomic absorption spectrometry (CVAAS) was determined. The biological absorption coefficient, bioconcentration factor, and translocation factor of Hg have been presented. Cirsium arvense therefore had a higher bioconcentration factor (BCF) of 2.6–5.15 mg/kg, and a transfer factor (TF) of 0.24–0.36 indicating a higher efficiency for phytostabilization. Both the rate and time of extractions of Hg from the tailings by Cirsium arvense are efficiently improved in the combined electric current and iodide treatment. Plant and electric current combined treatment and plant and iodide combined treatment had only 60 and 50% phytostabilization rates, respectively. The combined plant, iodide, and electric current treatment has proven to be superior with about >90% Hg removal rate. Therefore, the combined plant, iodide, and electric current treatment resulted in a higher Hg removal efficiency by Cirsium arvense in a shorter period due to higher solubilization rate and electromigration effects on Hg species.

Crustal Melting Recorded by Dykes along the Gold-bearing Melanson Brook Fault, Northern New Brunswick Appalachians

Dykes intruding along the Melanson Brook Fault record two magmatic episodes in northern New Brunswick. Dykes at the South Gold Zone of the Elmtree gold deposit are aphanitic and magnesian-calcic, whereas those at Ellis Brook (2.5 km to the west) are ilmenite-series and weakly peraluminous with hornblende- and plagioclase-porphyritic phases. Elevated 147Sm/44Nd generated by partial melting, titanium depletion, absence of rare earth element fractionation, and trondhjemite-like compositions indicate the South Gold Zone dykes were sourced from low-volume fluid fluxed melting of gabbroic crust. A Sm-Nd depleted model mantle age of 1.1 Ga for the Ellis Brook dykes suggests that they were sourced from melting of Ganderian crustal rocks rather than the sinking Acadian slab. 143Nd/144Nd evolution curves for the South Gold Zone dykes intersect that of the Ellis Brook dykes at 432 Ma and 427 Ma. This suggests that the magma from which the South Gold Zone dykes crystallized was extracted from a similar source area as the magma that generated the Ellis Brook dykes. Evidence of fluid exsolution in the Ellis Brook dykes indicates they could be a potential source for reduced intrusion-related gold mineralization. The Ellis Brook dykes yielded a U-Pb zircon age of 391 ± 5 Ma, which is consistent with the timing of oceanic slab break-off at the end of the Acadian orogenic cycle. Extraction of South Gold Zone magma occurred up to 40 Myr earlier, likely during the Salinic orogenic cycle.