Mining Activities Research Articles

Adsorption of lead (II) in a single and multi-metal system by hydrochar from pulp and paper sludge

AbstractLead (II) is one of the most toxic heavy metals found in South African wastewater due to various mining activities. Hence, effective and cheaper methods are needed to treat this wastewater before it is released to the environment. The effectiveness of hydrochar, synthesised from pulp and paper sludge, as an adsorbent for lead (II) removal from synthetic wastewater was determined. The effect of adsorbent dosage, solution pH, lead (II) initial concentration and time on the adsorption of lead by the hydrochar was investigated. The hydrochar was synthesised at 180, 220 and 250 °C. The most favourable hydrothermal carbonisation (HTC) temperature to synthesise pulp and paper sludge hydrochar for lead (II) adsorption was 180 °C based on the temperatures investigated. The hydrochar synthesised at 180 °C were modified with sodium hydroxide to improve its metal uptake. FTIR results showed that the NaOH modification increased the concentration of oxygen containing functional groups. Furthermore, the BET surface area of the hydrochar increased after modification. The hydrochar had a cellulose crystalline structure. The sodium hydroxide modification increased the maximum adsorption capacity from 24.72 to 37.32 mg.g−1. Moreover, the modified hydrochar synthesised at 180 °C (HC-180-NaOH) was effective in the adsorption of lead (II) in the presence of copper (II), cadmium (II) and zinc (II) where the affinity of the heavy metals towards the hydrochar was lead (II) > copper (II) > cadmium (II) ≈ zinc (II). Hence, the hydrochar, synthesised from waste material, is a potential adsorbent for the adsorption of lead (II) in industrial wastewater. Graphical abstract

Comprehensive review of the monitoring and sensing system in slopes with a special focus on the mining sector.

The failure of slopes due to various natural processes or extensive mining activities is a common problem that has an adverse impact on the environment and may result in severe casualties. Despite taking all the geotechnical considerations for the safe design of slopes, there could be unpredictable slope failure because of unexpected weather, seismic activities, or involvement of unidentified geological structures. Thus, continuous monitoring, forecasting, and warning of slope failures are imperative to save lives and property from devastation. This study was conducted to review the various slope monitoring techniques and propose the best possible monitoring system. The conventional instruments used for slope monitoring are wired, involving the human presence. In contrast, the economic Wireless Sensor Networks (WSNs), being less complex, may be utilized for real-time slope monitoring from a distant place to provide early warning about an imminent failure. The proposed early warning monitoring system will consider the local site conditions and be able to obtain various kinds of data regarding the factors influencing slope stability. The monitoring system will be flexible and efficient enough to provide timely warnings with a much higher life time by utilizing energy-efficient ZigBee protocols for communication. A switching mechanism is also proposed to take advantage of network topologies like star and tree. During bad weather, star topology will provide data at a higher rate, and during good weather conditions, tree topology will provide data at a lower rate by letting some nodes go into sleep mode, thus decreasing power consumption.

Impact of Sand Mining on Bathymetry of the Meghna River

This study aims to evaluate the morphological changes of the lower Meghna River in Bhola district due to reckless sand mining from riverbeds. It has been done based on primary data collected from the field and secondary data, such as river bathymetry of 2006, 2012, and 2022 from BIWTA and Landsat Imageries of 2006, 2016, and 2023 from USGS Earth Explorer. The study demonstrates that extensive sand mining activities in the lower Meghna River significantly affect river bathymetry and accelerate riverbank erosion. Lower Meghna River experiences a higher erosion rate due to prolonged and intensive sand mining. The erosion rate increased significantly between 2020 and 2021, with the riverbed eroding at an accelerating rate, highlighting a critical situation in the region. However, FGD and case studies from the field show that the impact of sand mining is not only confined to river morphology change but many more ecological, socio-political, economic, environmental, and governance issues are also linked with sand mining activities. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 13(1), 2024, P 21-28

Distribution characteristics, sources and risk assessment of heavy metal(oid)s in road dust from a typical lead-zinc mining area in South China.

Although the construction of green mines has effectively reduced soil pollution issues, dust contaminants continue to pose potential risks to human health and environment. This study investigated the concentrations, sources, and human health risks of metal(oid)s present in road dust across different functional zones of the largest lead-zinc mine in Guangdong Province, China, namely the Fankou lead-zinc mine. First, a systematic collection of 45 dust samples from six functional zones was conducted, focusing on the concentrations of ten heavy metal(oid)s (HMs), including As, Cd, Pb, and Zn etc. The results indicate that mining and smelting activities at the Fankou lead-zinc mine dictate the accumulation and distribution of HMs in the dust across the various functional zones. Except for Mn, Cr, and Thallium (Tl), the concentrations of other HMs significantly exceed the soil background values. These HMs primarily originate from mixed sources, including natural, traffic, and industrial activities. In particular, the presence of As, Cd, Pb, and Zn in the dust resulted in moderate to severe pollution, posing extremely high potential ecological risks. Furthermore, the bioavailable concentrations of HMs in the dust were analyzed using two in vitro gastrointestinal simulation methods: Physiologically Based Extraction Test (PBET) and Simplified Bioaccessibility Extraction Test (SBET), allowing for a further assessment of metal bioavailability and estimation of (non)carcinogenic risk probabilities for humans. The bioaccessible heavy metal contents extracted through SBET and PBET were relatively low, with most samples exhibiting bioaccessibility below 40%. In comparison to the total concentrations of HMs in the dust, the estimated non-carcinogenic risks (HQ and HI) and carcinogenic risks (CR) associated with bioavailability (PBET and SBET) for As, Cd, Cu, Sb, Pb, and Zn were significantly reduced, falling within safe values for both adults and children. However, the carcinogenic risk posed by total As remains a concern for local adults and children, indicating that the potential carcinogenic risk of As should not be overlooked. Therefore, additional protective measures should be considered to reduce resident exposure to dust, particularly in the core production areas of the mining district.

Analysis of Influencing Factors of Water and Sediment Condition Change in Fenhe River

Fenhe River is the second largest tributary of the Yellow River, and its water and sediment conditions have undergone tremendous changes in the age scale. The change of water and sediment conditions will inevitably lead to the change of river morphology, which poses a threat to the surrounding ecological environment and building safety. Firstly, this paper analyzes the changes of water and sediment conditions in Fenhe River through historical data. Secondly, according to the engineering measures and policies in the Fenhe River Basin, the influencing factors are put forward. Finally, the effects of rainfall, soil and water conservation, hydraulic construction, industrial water and coal mining on river flow and sediment conditions are considered. The results show that the increase of rainfall and inflow will weaken the sediment generation and carrying capacity, and further reduce the sediment yield. Soil and water conservation will effectively intercept runoff and sediment, reduce the content of the two in the river ; reservoir construction will regulate runoff and incoming sand to reduce the content of river sand. Industrial development and reservoir filling will reduce the amount of river water ; coal mining activities may aggravate the infiltration of the leakage area, resulting in a decrease in upstream runoff.

Heavy Metal Pollution Characteristics and Risk Assessment of Soil-crop System in Gold Mine Activity Area

A contamination analysis was conducted on the soil and crops in the Liu Jia Dian gold mining area of the Pinggu District, Beijing, utilizing the contents and seven-step forms of heavy metals （Hg, Cd, Cr, Pb, and As） in soil and the heavy metal contents in crops at the same location. An assessment of ecological risk caused by heavy metal contamination in the soil and crops was carried out using the enrichment coefficient method and the risk assessment coding method. The study investigated the process of heavy metal absorption and enrichment in the soil-crop system, aiming to establish a scientific foundation for preventing and controlling soil pollution, as well as ensuring the safety of edible crops in the study area. Evidence indicated the presence of soil contamination by heavy metals in the study area, with Cd, Pb, and As being the primary pollutants. Moreover, the distribution of pollution levels could be categorized as severe, moderate, and mild, with proportions of 26.09%, 4.35%, and 10.87%, respectively. The content of each heavy metal decreased following the implementation of environmental governance； however, the ecological risk remains present. Hg, Cr, Pb, and As posed minor ecological risks； however, Cd had a high ecological risk, making it the primary soil ecological risk factor. Fruits, nuts, and cereals in the Pinggu gold mining area remained uncontaminated. Various degrees of contamination were found in melons, rhizomes, and leafy vegetables. The Chinese cabbage, Chinese chive, radish, and eggplant were heavily contaminated, with Cd and Pb being the primary sources of contamination. The accumulation of heavy metals in crops was intricately linked to gold mines and their mining operations. The accumulation of Cd in crops was mainly influenced by the high availability of Cd in soil, whereas the accumulation of Pb was mainly influenced by the high concentration of Pb in the soil. The concentration of heavy metals in the soil and their bioavailability in the Pinggu gold mining area indicated the accumulation of metal elements in crops and impacted the geographical distribution of heavy metal pollution in crops. The physiological characteristics of crops could affect the degree of heavy metal enrichment in the gold mining area. The order of heavy metal accumulation, from highest to lowest, was as follows： leafy vegetables, melons, rhizomes, cereal, fruits, and nuts. Peppers and eggplants were limited in their planting variations for melons, while leeks and cabbages were restricted for leafy vegetables, given the current agricultural planting conditions in the study area.

Estimating Groundwater Inflow to The Underground Mine Works using a 3D Groundwater Model at Vein Kubang Cicau, UBPE Pongkor

Estimating groundwater inflow to underground mines is essential for ensuring that mining activities can be conducted safely and continuously. Research conducted at UBPE Pongkor indicates that the veins have the fault connectivity with the Kubang Cicau vein showing potential for deeper mining, while other veins are expected to become exhausted. As the result, the Kubang Cicau vein will likely be at a lower elevation in the future. Planning decisions regarding groundwater control measures, such as dewatering, can be made in advance, contributing to a more efficient assessment of the economic feasibility of mining development. Groundwater modeling using MODFLOW software predicted a maximum groundwater discharge of 55 L/s. To address the model uncertainty, a sensitivity analysis was performed by increasing the hydraulic conductivity parameter by two order of magnitude, as this value significantly affects groundwater inflow. Conversely, decreasing the hydraulic conductivity by two order resulted in a new discharge estimate of 87 L/s. In the worst-case scenario, with the highest specific storage values, the inflow increased to 76 L/s. This demonstrates that although changes in specific storage have a notable effect on groundwater inflows, the impact is less pronounced compared to the changes in hydraulic conductivity. Nonetheless, Ss remains a key parameter, particularly in transient simulations where storage plays a more significant role in the system response to changes in water levels.

RECLAMATION COST CALCULATION OF PT. X IN SORONG CITY, SOUTHWEST PAPUA PROVINCE

Reclamation is an effort carried out throughout the mining process to organize, restore, and enhance the quality of the environment and ecosystem, so that the area can function again according to its intended purpose. In the mining industry, companies are required to conduct reclamation. Before carrying out reclamation, the company must calculate the required reclamation costs. PT. X is one of the companies engaged in andesite mining, which is administratively located in Saoka Village, Maladumes District, Sorong City, Southwest Papua Province. After completing the mining activities, PT. X will carry out reclamation by planting pine trees during the period from 2024 to 2028. Based on this, it is necessary to calculate the reclamation costs to determine the expenses the company will incur for this activity. The reclamation cost calculations are based on the Minister of Energy and Mineral Resources Decree Number 1827/K/30/MEM/2018, which outlines the guidelines for implementing Good Mining Engineering Principles. Reclamation costs consist of both direct and indirect costs. Based on the research findings, the total direct and indirect costs that PT. X must incur for reclamation activities from 2024 to 2028 are IDR 359,238,257 and IDR 119,972,490, respectively. Therefore, the total reclamation costs PT. X will incur for the reclamation activities from 2024 to 2028 amount to IDR 479,210,747

Investigating Rainfall Patterns in South Singhbhum: A Non-parametric Approach Utilizing Mann-Kendall Tests and Sen's Slope Estimator

Aims: The South Singhbhum region is a physical region that experiences monsoon climate and frequent tropical cyclones and has global importance because of its abundant mineral resources like iron, manganese and its mining activities. The agricultural practices mainly depend on rainfall as it is a hilly area. For that reason, sustainable management is necessary to fulfill ecological, industrial, and community water requirements. So, the investigation carried out in this study focuses on the analysis of rainfall patterns within the South Singhbhum region by utilizing non-parametric statistical methodologies with the objective of identifying any discernible trends and variations that have occurred over time. Place and Duration of Study: South Singhbhum region of Odisha is extended between latitude to and longitude to . The area spread over on 45 blocks of Eight district in Odisha, India. The duration of time extended from 2008 to 2022. Methodology: The Mann-Kendall (MK) test is utilized to effectively detect the presence of monotonic trends within both the annual and seasonal rainfall datasets. Furthermore, the sequential Mann-Kendall (S-MK) test is employed to provide a comprehensive understanding of the temporal progression of these identified trends. The Sen's slope estimator is applied to accurately quantify the magnitude of the observed changes in rainfall patterns. Results: The annual study shows a steady declining trend from 2008 to 2021, with a Sen's Slope of 2.0376 and a Z value of 1.0949. However, March is the only month with a positive trend, as seen by its Sen's Slope of 3.0328 and Z value of 1.9708. There are significant variances in Sen's Slope values, which show disparities in the amount of changes, even if negative trends are common. The steepest negative slope is in July (-3.554), and the highest slope is in August (8.981). The S-MK Test was used to determine the start time of the South Singhbhum Region's annual rainfall time series, which revealed statistically declining patterns. It has been observed that the area's rainfall tendency varies frequently. In 2009, 2011, 2017, and 2019, the lines in the u(t) and u'(t) graphs intersect. The rainfall series experienced a reduction from 2008 to 2009, a rise from 2009 to 2011, a decrease from 2011 to 2017, another increase from 2017 to 2019, and a decline starting in 2019. Conclusion: The findings demonstrate that the South Singhbhum Region's rainfall patterns are trending negatively, which makes it clear that quick implementation of comprehensive water resource management methods is necessary to support sustainable development initiatives in the near future.

Análise dos desastres socioambientais no contexto da grande mineração em minas Gerais, Brasil, sob o prisma da criminologia verde (Green Criminology)

The study focused on analyzing socio-environmental disasters resulting from mining activities in Minas Gerais, Brazil, through the lens of Green Criminology. Using the hypothetical-deductive method, the research sought to identify alternative and falsifiable hypotheses, allowing for a critical analysis of the issues in question. Minas Gerais plays a crucial role in iron ore production, contributing significantly to the Brazilian and global economy. The most notorious disasters include the collapse of tailings dams, the contamination of rivers and the negative impact on the quality of life of local communities. These growing concerns require an in-depth and critical analysis to understand the criminal and socio-environmental dimensions present in the context of mining. In order to achieve the general objective of this research, specific objectives were established. Firstly, the study sought to contextualize large-scale mining in Brazil, highlighting its economic importance and the social and environmental implications related to this activity. The research also investigated the adherence of Green Criminology to the reality of mining, considering the legal and criminological implications involved. In addition, it explored the connections between crimes committed by powerful entities in the mining sector and the Green Criminology approach. The application of damage theory was highlighted as an analytical tool to examine the wider implications of these practices. The conclusion of this study highlights the need for a more comprehensive and sustainable approach to dealing with the challenges of large-scale mining and the resulting socio-environmental disasters. Furthermore, it emphasizes the importance of assessing the different individual responsibilities in relation to environmental damage and highlights the need for a critical analysis of the relationships between power, crime and social harm, especially in the context of the mining industry and socio-environmental issues.

Honey production in the south bythe Legal Amazon: a study on the potential contamination of mercury in apiaries.

Artisanal and small-scale gold mining (MAPEOs) are considered to beone of the main sources of mercury release into the environment. Considering the gold mining activities, this study evaluated the Hg concentration in 27 apiaries (Apis spp.) in the South of the Legal Amazon, Mato Grosso State, Brazil. A total of 243 samples distributed in 81 samples of bees, 81 beeswax, and 81 of honeys, collected between the months of July and November 2022, were analyzed. One bee sample showed Hg concentration above the limit of quantification (68.8ngg-1), 27 samples were between the limit of detection and limit of quantification (15 samples of bees, 8 of wax and 4 of honey). In all study areas, trace levels of Hg concentration were detected, 12 near MAPEOs areas and 16 near crop areas. It recorded that the honeys analyzed in this study in Mato Grosso are not contaminated by Hg, not offering any risk to consumers of the product. It is noteworthy that the use of bioindicator tools such as bees, beeswax, and honey is effective in relation to Hg monitoring in apiaries. It can also infer that the implementation of beekeeping in areas that will go through experiencethe process of environmental recovery, after the mining exploitation, is feasible, in line with permanent biomonitoring of the region.

Assessing Species Richness with Camera Trap Surveys During Five Years of Large-Scale Mining Disruptions

In the Northern Cape Province of South Africa, an investigation was launched into the impact of large-scale open-pit mining on wildlife ecology and populations, more specifically on the animal species richness and detection rates across different vegetation types. Using camera traps, we monitored a 43,000-hectare area, which included active mining areas and adjacent lands, over a period of five years (2020–2024). Data on 44 animal species ranging from small mammals to large megaherbivores were collected, with a large variation in species richness across the study site being observed. The detection of species that are of conservation concern, such as the vulnerable Temminck’s ground pangolin (Smutsia temminckii) and endangered mountain reedbuck (Redunca fulvorufula), highlighted additional potential risks that mining activities pose to biodiversity in the area, emphasizing the importance of monitoring biodiversity in areas that are impacted by large-scale anthropogenic and mining activities. Furthermore, the results suggest that some areas may require a more targeted approach to conservation in order to mitigate the disruptive effect of mining. Benchmarking the species present and proving the presence of endangered and vulnerable species prove the successful first steps into understanding habitat disruption caused by mining activities and will guide future conservation and management efforts.

Hazard Study of Sludge from Mining Wastewater Treatment Systems (Tailings), Accumulation of Contaminants and Potential Utilization Proposals

The increase in gold mining activities has led to a substantial rise in tailings generation, which carry distinct physicochemical and microbiological properties. This study aimed to evaluate the hazardous characteristics of mining tailings using the CRETIB (corrosivity, reactivity, explosiveness, toxicity, ignitability, biological-infectious) methodology. The research analyzed concentrations of heavy metals including arsenic, cadmium, copper, chromium, lead, mercury, nickel, and zinc, alongside parameters such as pH, cyanide, hydrogen sulfide, and coliform bacteria. Tailings samples were collected from a mine in Ponce Enriquez, Ecuador, at the surface and at a depth of 2 m across three monitoring campaigns. The results indicate that the tailings do not exhibit hazardous characteristics according to CRETIB criteria. While arsenic, chromium, copper, nickel, zinc, and mercury concentrations showed significant differences between the surface and 2 m depth, accumulating at the bottom of the tailings dam by 30–72%, parameters such as pH, cyanide, and hydrogen sulfide were higher at the surface, likely due to volatilization and precipitation effects. Lead did not show significant differences, but also tended to accumulate at depth. These findings suggest that the tailings could be safely utilized in the production of construction materials such as bricks, geopolymer concrete, and fiber cement, promoting circular economy practices and sustainable development in mining.

Mine design on mangrove block site of Indrabakti Mustika company in Lameruru, North Konawe regency, Southeast Sulawesi province

Abstract The increasing demand for nickel in Indonesia grows with the trend of electric vehicles, inspiring nickel mining companies to enhance their supplies. PT IBM, a company engaged in nickel mining, is operating laterite nickel resource mining activities in a 576-ha area of open-cut mining in the village of Lameruru, North Konawe Regency, Southeast Sulawesi province. The mining activities are divided into several blocks, including a mangrove block to meet the production target of 125,000 WMT ore per month in case other blocks fail to meet the cut-off grade (CoG) of 1.2% Ni. This study recommends a mining design to effectively determine the overburden and ore extracted in the mangrove block. This quantitative research collected data from literature studies and field studies. The results of the mine design revealed eight mining sequences with a total amount of mined overburden and mined ore volume of 1,584,589 BCM and 1,069,481 WMT, respectively. The stripping ratio obtained was 1:1.48, indicating that it takes 1.48 BCM overburden to obtain 1 WMT ore.

Geochemical assessment and transfer of potential effects of metallic trace elements around abandoned mining sites in Kettara region (Morocco)

The degradation of environmental quality due to pollution is a pressing concern worldwide, particularly in areas that have been abandoned after mining activities. One significant aspect of this degradation is the contamination of soil and water resources by Metallic Trace Elements (MTE). These elements, originating from mining operations, pose serious environmental and human health risks, necessitating urgent attention and remediation efforts. Understanding the characteristics and extent of MTE contamination in abandoned mining areas is crucial for effective environmental management and sustainable development. In this context, this study aims to investigate the patterns, distribution, and impacts of MTE contamination in soil and water resources within Kettara abandoned mining areas (Morocco), offering insights into potential mitigation strategies and policy interventions to address this critical environmental issue. Stream and groundwater samples were collected in the Kettara region where the abandoned tailings constitute with Acid Mine Drainage (AMD), the principal source of this contamination. Stream samples were collected in 2018 at fourteen points near sixteen hydrogeological wells and situated at different distance from the pollution source.This study addresses an environmental concern, focusing on the dispersion of MTE such as Arsenic, Zinc, and Nickel in both streams and groundwater. Through geochemical analysis, it is revealed that Arsenic is particularly prevalent, with higher concentrations detected in streams, especially those proximate to mining waste sites. The main sampling water near the abandoned mine shows several anomalies (As, Ni and Zn). The higher As concentration in the stream samples E1 and E2 with 179.55 and 96.63 ppm and near the mine wastes. The concentration of As is also higer in the water samples especially in the hydrogeological well P21 and P2 with 9.665 and 7.798 ppm.The presence of MTE in groundwater is linked to various factors, including the direction of flow (vertical or lateral) from soil to groundwater and the hydraulic conditions (presence of the drainage axis that is materialized by the convergence of the groundwater flow from the upstream to the downstream, generally from the hydrogeological wells P1 to P23). The hydraulic relationship between streams and groundwater, hydrogeological properties such as aquifer porpermeability (vertical scale 2.5 × 10-14 to 1.31 × 10-12 m/s and horizontal scale 9 × 10-14 to 0.37 × 10-9 m/s) and transmissivity (about 10−2 m2/s), and the configuration of the piezometric geometry (including the presence of drainage axes and divisional boundaries within the Ketarra groundwater) are factors that contribute to the mobility and distribution of MTE within the water resources of the Kettara basin.

Fixation behavior of oceanic manganese nodule-sodium alginate composite microspheres for heavy metal release during manganese nodule mining

Research on the environmental impact of deep-sea mining is crucial, particularly for fragile deep-sea ecosystems. This research focuses on the issue of heavy metal release during mining activities. Through simulation experiments, we investigated the release of Cu2+, Co2+, and Ni2+ from sediments under disturbance conditions and the fixation behavior during the deployment of ocean manganese nodule-sodium alginate composite microspheres (OMN@SA). The experimental results revealed that mining disturbances cause the release of 0.291% of Cu2+, 7.34% of Co2+, and 4.13% of Ni2+ from sediments into the water, primarily in the form of exchangeable metals. Compared with the bottom adsorption, OMN@SA has a faster adsorption rate in the slow settling process. The removal rates of Cu2+, Co2+ and Ni2+ reached 54.0%, 78.3% and 61.8% for 5 h adsorption, and the bottom adsorption removal rates reached 96.4%, 97.8% and 95.1% for 30 d adsorption, which has a good removal effect. In addition, OMN@SA can effectively block the diffusion of Cu2+, Co2+, and Ni2+ from interstitial water to overlying water, and reduce the influence of interstitial water on overlying water. SEM-EDS, FTIR, and XRD analyses revealed that OMN@SA adsorbs heavy metal ions through its abundant -OH groups and incorporates Cu2+, Co2+, and Ni2+ into the crystal lattices of vernadite and todorokite via substitution or intercalation. This study provides guidance for the remediation of heavy metal release from deep-sea mining using adsorption methods and demonstrates the promising application prospects of OMN@SA.

Spatial distributions, potential sources, and ecological risks of heavy metals in stream sediments in Zambia

The ecological risk assessment and source identification of heavy metals (HMs) are significant for resource utilization and food security. This study aims to assess the spatial distributions, potential sources, and ecological risks of HMs in stream sediments in Zambia. Using 735 samples collected from stream sediments across the country and methods such as inductively coupled plasma mass spectrometry (ICP-MS), atomic fluorescence spectrometry (AFS), and X-ray fluorescence spectrometry (XRFS), this study determined the concentrations of the seven HMs, i.e., arsenic (As), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn). The spatial distributions of these HMs were determined using a Geographic Information System (GIS), and their ecological risks were accessed based on the analytical results of their potential sources. Additionally, this study explored the relationships between mining activities and regions with high heavy metal (HM) concentrations based on the statistical analysis of the HM concentrations and geology of the study area. The results indicate the stream sediments in Zambia exhibit average As, Cr, Cu, Hg, Ni, Pb, and Zn concentrations of 1.49 × 10−6, 19.34 × 10−6, 12.12 × 10−6, 12.70 × 10−9, 7.13 × 10−6, 12.52 × 10−6, and 16.30 × 10−6, respectively. The analytical results of the geoaccumulation index (Igeo) and potential ecological risk index (PERI) reveal the presence of relatively high As and Cu concentrations, especially in Copperbelt and North-Western provinces and areas surrounding Lusaka—the capital of Zambia. The HM contamination in stream sediments in Zambia is primarily caused by Cu and gold (Au) mining. This study exemplifies how to determine potential sources and ecological risks of HMs in stream sediments, holding important implications for nation-scale environmental contamination prevention and land utilization planning.

Nickel mine planning application to support smelter demand fulfilment: a case study of gag nickel mine

Abstract Gag Nickel is a mining project in West Papua developed by Antam, with a total resource of approximately 300 million wet metric tons. In the central block, mining activities are carried out to meet the demand target for the nickel smelter. There are two types of specifications, saprolite and limonite ores, each with specific grade requirement based on sales purchase contract. The aim of this study was to fulfill the long-term target from 2024 to 2028 through integrated mine planning to generate production scheduling plan based on agreed contract of around 6 million wet metric tons ore per year. The quantitative method was implemented to gather primary data, including the 6-meter-high bench and material classification based on specific quality of elements-compounds, and to use the secondary data such as reserve block model to create a reverse model. The challenges of this study included different ore specifications of each location of the hill, and constraints on limited stockyard location to support differentiation between two types of products. Based on the simulations performed, production and sales targets could be achieved according to predetermined product specifications, amounting to 6 million wet metric tons of saprolite and limonite with fluctuating processes during the period. From the scheduling results, the smelter supply composition ratio between saprolite and limonite was between 1.37 and 1.85. After the implementation above, Gag Nickel can conserve resources by optimizing reserves of both limonite and saprolite for optimum utilization.

Toxic layering and compound extremes: Per- and polyfluoroalkyl substances (PFAS) exposure in rural, environmental justice copper mining communities

Per- and polyfluoroalkyl substances (PFAS) are pervasive environmental pollutants with significant impacts on ecosystems and public health. This study aimed to characterize PFAS concentrations in an environmental justice community impacted by active/legacy copper mining, compounded by wildfires and flash floods. Additionally, the study explored the (re)mobilization of PFAS and co-occurrence with metal(loid)s following these events. Twenty-eight PFAS compounds in 35 residential and 8 control surface soil samples were analyzed via liquid chromatography-tandem mass spectrometry (LCMS/MS). The maximum total PFAS concentration observed in the residential samples was 96.40 μg kg−1, compared to 1.69 μgkg−1 in the control samples. Perfluorobutanoic acid (PFBA) had a maximum concentration of 61 μg kg−1 in residential samples, while Perfluorohexane sulfonic acid (PFHxS) had the highest concentration in the control samples at 0.92 μg kg−1. Long-chain PFAS were most dominant in this study. Perfluorooctane sulfonic acid (PFOS) (58 % of the samples), Perfluorooctanoic acid (PFOA) (35 %), and Perfluorohexane sulfonic acid (PFHxS) (72 %) exceeded the U.S. EPA Soil-to-Groundwater Risk-Based Screening Levels, highlighting the potential risk of contaminants migrating from soil to groundwater, which could ultimately impact groundwater quality. Co-occurrence analysis showed that increases in PFAS concentrations were positively associated with Zn (β = 1.25, p = 0.0034) and Ba (β = 1.23, p = 0.0284) but negatively associated with Pb (β = −0.83, p = 0.0115) and Co (β = −1.38, p = 0.04671). In general, a spatial distribution map indicated that greater PFAS concentrations were observed near potential sources i.e., active mines. This evidence combined with select metal co-occurrence highlights the potential role of mining activities on PFAS concentration.

Co-disposal as an alternative method for waste rock and tailings management–a review of geochemical aspects

Abstract Gold mining and processing activities produce at least two materials with adverse impacts on the environment: waste rock and tailings. Waste rock is generally disposed of in a waste rock dump (WRD) or in-pit backfill, while tailings are disposed to facilities such as landfill, tailings dam, or in-pit backfill. This separation is a common practice that requires a large area and specific technical considerations of respective materials and locations. Geochemically, waste rock can be potentially acid forming (PAF) and produce acid mine drainage, while tailings geotechnically have low stability due to the very fine particles. Combining these two materials in one placement location, known as co-disposal, is expected to benefits the geochemical and geotechnical aspects. The present research aims to design a geochemically-safe co-disposal of waste rock and tailings. Field kinetic geochemical tests were carried out using a 200-liter barrel in an open space area with different co-disposal compositions and treatments to identify the leachate and surface water quality. The results show that co-disposal with a 2:1 ratio of waste rock to tailings composition with the addition of lime sand of 15 kg/ton of tailings and compaction process gives the best results on leachate water quality under the natural condition during the test. This series of tests concluded to determine geochemical factors in co-disposal quality, namely pH value of tailings, lime dosage, the quality and exposure period of the waste rock, and the compaction process of the co-disposal layers.