Mine Site Research Articles

Plant traits regulated metal(loid)s in dominant herbs in an antimony mining area of the karst zone, China.

Understanding how plant functional traits respond to mining activities and impact metal(loid)saccumulation in dominant species is crucial for exploring the driving mechanisms behind plant community succession and predicting the ecological restoration potential of these plants. In this study, we investigated four dominant herbaceous species (Artemisia argyi, Miscanthus sinensis, Ficus tikoua, and Ageratina adenophora) growing on antimony (Sb) mining sites (MS) with high Sb and arsenic (As) levels, as well as non-mining sites (NMS). The aim was to analyze the variations in functional traits and their contribution to Sb and As concentrations in plants. Our results indicate that mining activities enhanced soil nitrogen (N) limitation and phosphorus (P) enrichment, while significantly reducing the plant height of three species, except for F. tikoua. The four species absorbed more calcium (Ca) to ensure higher tolerance to Sb and As levels, which is related to the activation of Ca signaling pathways and defense mechanisms. Furthermore, plant Sb and As concentrations were dependent on soil metal(loid) levels and plant element stoichiometry. Overall, these findings highlight the regulatory role of plant element traits in metal(loid) concentrations, warranting widespread attention and further study in the future.

Photosystem modulation and extracellular silicification in green microalgae: Key strategies for lead tolerance and removal

The escalating contamination caused by lead ions (Pb2⁺) and its harmful effects on all life forms has raised global concerns. Certain microalgae thrive in metal mining sites characterized by low pH and high concentrations of Pb2⁺, which are usually prohibitive for many microorganisms. Little is known about the mechanisms underlying the adaptation of such microalgae to these hostile conditions. In this study, we elucidated the adaptive strategies of the green microalga Micractinium belenophorum strain AUMW, isolated from a lead mining site, and its application for the removal of Pb+2. Results revealed that strain AUMW can efficiently tolerate up to 200 ppm of Pb+2 in an F/2 medium. Further experimental variables were optimized through response surface methodology (RSM), and 99.6 % removal of Pb2⁺ was achieved. Novel adaptive responses of strain AUMW to high levels of Pb2⁺ include: (i) activation of metal-protective response by modulation of quantum yield (Fv/Fm) and non-photochemical quenching (NPQ) of photosystem II; (ii) extracellular silicification encapsulated cells of strain AUMW and altered cell morphology from oval to hexagonal; (iii) silicification prevented intracellular translocation of Pb+2; (iv) silicification boosted adsorption of Pb+2, thus enhanced its removal. This study offers new insights into the protective role of silicification in green microalgae and its potential for the removal of metals from metal-polluted sites, waste from energy storage battery industries, and spent batteries. It also provides a solid base to explore the genetic and metabolic pathways involved in the adaptation of strain AUMW to elevated levels of Pb+2.

Comment on: The La Lucette Sb-Au-(W) vein-deposit (Armorican Massif, France): New time and genetic constraints to decipher the 310–295 Ma Sb-Au metallogenic peak in the Variscan Belt by

Recently, Cheval-Garabédian et al. (2023) published a paper in Ore Geology Reviews entitled “The La Lucette Sb-Au-(W) vein-deposit (Armorican Massif, France): new time and genetic constraints to decipher the 310–295 Ma Sb-Au metallogenic peak in the Variscan Belt.” Studies on Sb mineralisation are highly welcomed, especially in France, where there is a lack of updated data hindering a comprehensive understanding of this mineral system. The paper provides new mineralogical, fluid inclusion and geochronological data from historical collection samples of La Lucette mine, a mining site no more accessible since at least 40 years (Serment, 1978). These data, together with structural data from literature, lead the authors to build a metallogenic model related to dextral shear zone during the Carboniferous-Permian transition. The authors further argue for a single and unique 310–295 Ma Sb-Au metallogenic peak in the European Variscan Belt, a late Variscan hydrothermal event coeval with post-thickening tectonics (Munoz et al., 1992; Bouchot et al., 1997, 2005). This assertion is not correct. In this comment, we highlight that (i) several errors and approximations question the validity of their model, and (ii) the authors omit certain information that contradicts their metallogenic model. In our view, their data do not fully support the existence of a generalised and unique Late Carboniferous Sb-Au metallogenic peak in the French Variscan Belt. Furthermore, the idea defended by the authors that ore deposits occurred during dextral strike-slip tectonics that affected the area may better support a possible long-lived history during Palaeozoic times.

Integrated approach for seismic wave prediction and structural evaluation of Oya tuff quarry underground spaces: Field observations and numerical modeling

This study evaluates the structural stability of large underground spaces in seismic conditions, represented by the Oya underground stone mining plant. By directly monitoring the seismic response of the underground mining site, significant earthquake activities at the plate boundaries of the Tokyo region and Ibaraki Prefecture offshore area were observed. Additionally, through an in-depth analysis of seismic records from different locations within the underground structure, the dynamic characteristics and motion patterns of the Oya underground stone mining plant were revealed, revealing its movement trajectory during earthquakes. Additionally, this study innovatively applied seismic waves measured at the original site as input parameters and artificially generated seismic waves based on their response spectra. A numerical analysis was performed after ensuring the model's high correlation with the original site was met. The findings demonstrate that the results of both parameter input methods are confirmable and valuable. Under severe seismic conditions, instability was observed in some regions of the underground mining site. The study also discusses the location and damage mechanisms of the mining site's structure under seismic effects, providing valuable insights for the safety assessment of similar large underground spaces and proposing new approaches for selecting input parameters in seismic analysis.

Bioaccumulation of Heavy Metals in Living Organisms, Soil, and Health Risk Assessment: A Systematic Review of Mining Sites in the Philippines

Despite the known presence of heavy metals around mining sites, a critical gap exists in understanding how these metals accumulate in living organisms and soil. This lack of knowledge hinders effective management and poses potential health risks to surrounding ecosystems, including humans. This review included articles published between 2014 and 2024 that focused on bioaccumulation of heavy metals in living organisms, soil contamination at mining sites, and health risks associated with mining exposure. Articles were selected based on originality, full-text availability, and English language. Excluded were case studies, reviews without data, or articles lacking full text or English translation. All relevant studies were systematically selected from Google Scholar, ResearchGate, Elsevier, Springer, and Academia.edu to identify relevant research exploring the impacts of mining activities on local biota. The review identified a total of 25 studies. We were able to use 15 of these studies for a more in-depth quantitative analysis. The qualitative analysis of all 10 studies revealed that Arsenic, Copper, Nickel, Mercury, Chromium, Lead, and Zinc are the most frequently observed heavy metals impacting humans near mining sites. Among the identified heavy metals, Mercury and Arsenic stand out as posing the greatest health risk such as skin allergies, respiratory problems and various types of cancer. Their high toxicity and ability to bioaccumulate in the food chain are particularly concerning. Bioaccumulation means these metals become more concentrated at each level of the food web, posing a significant threat to top predators like humans. Specific species demonstrate significant metal accumulation, underscoring the toxicological risks associated with heavy metal bioaccumulation and the need for environmental intervention and monitoring to protect both organisms and ecosystems. Through this systematic review, the researchers aim to shed light on bioaccumulation patterns of heavy metals around mining sites. These findings will be crucial for developing better strategies to mitigate environmental impacts and protect the health of surrounding ecosystems.

Characterization, potential valuable metals recovery and remediation of historic wolframite mining waste

The understanding of tungsten (W) mineral weathering and mobilization in nature remains limited due to W being a transition element with a wide range of oxidation states, which enables it to form a variety of complex chemical compounds. This study examined W mining waste at the abandoned Wolfram Camp mine in North Queensland, Australia, to address this gap. The mineralogical analysis showed the W tailings primarily consisted of silicates, including quartz, illite/mica, plagioclase, and K-Feldspar, with low WO3 content. Static acid mine drainage (AMD) tests indicated most tailings were non-acid forming, while groundwater samples exhibited acidification, with pH ranging from 3.8 to 5.2. The reprocessing trials using gravity separation and bioleaching demonstrated promising results, suggesting both techniques could effectively recover resource and decontaminate the mining waste. The gravity separation reprocessing test has successfully recovered 48.4% W from the tailings, with the resulting W concentrate achieving a 21.6% WO3 grade. On the other hand, the bioleaching reprocessing exhibited a remarkable 44-fold enrichment of W from the tailings, with 2.2% W in the AMD sediment. Synchrotron-based XFM/μ-XANES imaging analysis revealed significant wolframite weathering in reprocessed W concentrates. This study proposed a comprehensive approach, integrating environmental remediation and resource recovery technologies, to repurpose abandoned W mining waste. Passive treatment appears to be an economical option for remediating abandoned W mine sites. The findings provide valuable insights for sustainable W mining waste management and the rehabilitation of the abandoned Wolfram Camp W mine site.

Green Transformation of Mining towards Energy Self-Sufficiency in a Circular Economy—A Case Study

This article presents the concept of green transformation of the coal mining sector. Pump stations that belong to Spółka Restrukturyzacji Kopalń S.A. (SRK S.A., Bytom, Poland) pump out approximately 100 million m3 of mine water annually. These pump stations protect neighboring mines and lower-lying areas from flooding and protect subsurface aquifers from contamination. The largest cost component of maintaining a pumping station is the expenditure for purchasing electricity. Investment towards renewable energy sources will reduce the environmental footprint of pumping station operation by reducing greenhouse gas emissions. The concept of liquidation of an exemplary mining site in the context of a circular economy by proposing the development/revitalization of a coal mine site is presented. This concept involves the construction of a complex consisting of photovoltaic farms combined with efficient energy storage in the form of green hydrogen produced by water electrolysis. For this purpose, the potential of liquidated mining sites will be utilized, including the use of pumped mine wastewater. This article is conceptual. In order to reach the stated objective, a body of literature and legal regulations was analyzed, and an empirical study was conducted. Various scenarios for the operation of mine pumping stations have been proposed. The options presented provide full or nearly full energy self-sufficiency of the proposed pumping station operation concept. The effect of applying any option for upgrading the pumping station could result in the creation of jobs that are alternatives to mining jobs and a guarantee of efficient asset management.

Case Report: Multidisciplinary management of severe blast-related craniofacial and ocular injuries at artisanal gold mining sites in Niger: An unusual case report and comprehensive literature review

Blast-related craniofacial and ocular injuries have traditionally been associated with battlefields. In civilian populations, these injuries were infrequent, primarily arising from accidental explosions or terrorism incidents. Explosions can inflict severe damage to the neurological, ocular, and auditory systems through blast waves, high-velocity foreign bodies, and thermal radiation. The pathophysiology of blast-related craniofacial injuries is specific and complex, with severe cases often involving both penetrating and blunt trauma, leading to high mortality and morbidity rates. These injuries necessitate multidisciplinary management and can be defined as intracranial polytrauma. Recently, Niger has seen a surge in blast injuries, predominantly due to the increase in clandestine artisanal gold mining. Managing these injuries in resource-limited settings poses significant challenge. Comprehensive national data on these injuries are sparse due to high pre-hospital mortality rates and their infrequent occurrence, resulting in limited experience among our local physicians in their management. We present a rare case involving an artisanal gold miner with a history of smoking and previous concussions from explosion exposures. The patient was transferred to our hospital following severe craniofacial and ocular injuries caused by an accidental dynamite explosion at a mining site. On admission, the patient presented altered consciousness, agitation, unstable vital signs, multiple craniofacial wounds, including a large frontal wound with brain substance extrusion, diffuse facial burns, left globe rupture, and rhinorrhagia. After resuscitation and stabilization, brain imaging revealed multiple complex craniofacial fractures with foreign bodies. The patient underwent multidisciplinary surgical management. However, the postoperative course was complicated by post-concussive syndrome, and infection of the surgical wounds, necessitating surgical revision. Following the second surgery, the postoperative course was uneventful, although the patient experienced reduced visual acuity. This case highlights the management challenges in Niger and underscores the urgent need for clinical studies and training for gold miners to enhance safety practices in their activities.

TEKNOLOGI REKLAMASI LAHAN BEKAS TAMBANG TIMAH MELALUI PEMBERIAN BAHAN AMELIORAN DAN PEMILIHAN JENIS TANAMAN: STUDI KASUS KEPULAUAN BANGKA BELITUNG

Indonesia, besides being the country with the largest nickel reserves in the world, also holds the largest tin reserves globally in 2023. Meanwhile, in terms of production, Indonesia ranks second after China. Tin mining in Indonesia has led to serious environmental damage, illustrated by the numerous open pits and inadequately restored tin mining sites. The characteristics of soil in these post-mining lands generally include sandy texture, low pH, nutrient deficiencies, low organic carbon content, and low water holding capacity. This study aims to improve the soil chemical properties in post-mining lands by utilizing the KOMFABA technology, which consists of a mixture of compost and fly ash-bottom ash with appropriate dosages tailored to the type of crops to be planted, along with revegetation strategies involving suitable plant selections. The research methodology consists of field experiments to test the application of KOMFABA with various dosages and crop types, as well as a literature review to identify suitable revegetation strategies. The research result show that Indonesia holds tin reserves of 800,000 tons, making it the largest in the world, with a production of 74,000 tons, placing it second after China. Additionally, the results of KOMFABA testing demonstrate its effectiveness in improving soil chemical properties such as soil pH, organic carbon content, cation exchange capacity (CEC), nutrient content, and soil base saturation. The success of reclaiming post-mining lands also dependent on proper fertilization dosages and suitable plants selection.

Evaluation of soil pollution effects on maize (Zea mays) at selected Pb-Zn and limestone mine sites in Ebonyi State, Southeastern Nigeria.

This research examined soil contamination and the uptake of potentially toxic elements (PTEs) by maize plants in mining communities. We collected 192 soil samples and 40 maize plant samples from two mining areas and a pristine site. We analyzed the physical properties and element content of the soil, including phosphorus, nitrogen, potassium, Fe, Zn, Co, Pb, Cd, Cr, and Ni. We also measured the elemental concentrations in the maize plants. The study found higher levels of Zn, Cu, and Pb at the mining sites compared to the control areas. The pollution factor (CF) indicated pollution with Cu > Pb > and > Zn at both mine sites. The pollution index (PLI) showed no pollution in the Nkalagu mine and control sites, but heavy and moderate pollution at the Ameka mine and control sites, respectively. The Ameka mine site was enriched with Zn. The bioaccumulation coefficient (BAC) was < 1 except for Zn at the Nkalagu mine and control site. The transfer factor for Fe and Zn from root to shoot was > 1. Pb was > 1 in all study areas except the Ameka mining areas. The results suggest remediation is needed for the two mine sites, especially at Ameka.

Harnessing phosphate limestone waste as a cost-effective solution for acid mine drainage treatment

Mining mineral ores like pyrrhotite often generates positive and negative outcomes for the community. On the one hand these valuable minerals are explored to provide economic opportunities. On the other, mining pyrrhotite presents adverse environmental and health effects that relates to acid mine drainage (AMD) formation in abandoned mines. This suggest that the sustainable mining of valuable minerals in Pyrrhotite requires cost and environmentally friendly approaches. In this research, we simulate in-situ neutralisation effect of phosphate limestone waste (PLW) on AMD from two mining sites in Morocco under continuous oxic conditions. To this end, we conducted batch tests to assess the effectiveness of PLW in mitigating AMD and releasing contaminants. These tests involved reacting limestone particles (at two sizes: <2 cm and < 4 cm) with AMD leachates over a five-day period The results indicated that the AMD is characterised by a pH of 2.5 and an electrical conductivity of 11.8 mS/cm. The inductively coupled plasma optical emission spectroscopy (ICP-OES) analyses showed a high sulfate concentration of 3668.83 mg/L and the presence of some metals, notably copper, aluminium, and iron. The neutralisation process of the AMD using PLW under oxic conditions was highlighted by the variation in pH while the water was in contact with the PLW. The pH rose from 2.5 to 5.25 while the electrical conductivity decreased from 11.8 to 7.03 mS/cm. During the treatment of the AMD with PLW, the percentage of sulfate removal from the effluent was 35 %. In addition, iron and aluminium were significantly removed from the AMD with a percentage of 99 % in the leachate. Therefore, these results indicate that neutralising AMD using this passive treatment approach is effective and may serve as a cost-effective mitigation for AMD, since no excessive grinding is required for the PLW.

Visiting mine reclamation: How field experience shapes perceptions of mining.

Recognizing the prevailing negative public opinion on mining, it is important to understand how firsthand encounters with mining activities might influence these perceptions. This study investigates how field trips to open pit coal mines and their reclamation sites in the Czech Republic affected the attitudes of 148 university students toward mining and mine reclamation. Using pre and post trip questionnaires, we observed significant changes: Students became less neutral about mining, saw it as a temporary disruptive activity, expressed reduced concern for social conflicts in mining areas, and showed increased support for the ecological restoration of post mining sites. These findings underscore the transformative impact of direct engagement with mine reclamation activities on shaping attitudes. Understanding these effects offers promise for positively shifting public perceptions of mining practices, emphasizing the potential for constructive changes in attitudes through field experiences with reclamation efforts in the Global North.

Amendments promote Douglas-fir survival on Formosa Mine tailings.

While mining provides valuable metals and minerals to meet societal demands, it can cause environmental contamination from the residuals (i.e., tailings) of mining. Tailings are often acidic, laden with heavy metals, and lacking adequate nutrients and physical conditions for plant growth, precluding the establishment of plant cover to reduce the offsite movement of mining wastes. This paper describes a case study at the Formosa Mine in Douglas County, Oregon, where tailings were amended with a mixture of lime, biosolids, biochar, and microbial inoculum to facilitate establishment of Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) seedlings. Results show that the tailings pH increased, and Douglas-fir seedlings survived and grew with these amendments. After 2years, pH did, however, decrease in some downslope locations and was associated with an increase in tree mortality. This suggests that tailings conditions should be monitored, and amendments should be reapplied as needed, particularly in areas receiving acidic runoff from unamended upslope tailings, until the seedlings are fully established. This study not only provides a prescription for the addition of biochar and other amendments to enhance plant growth for revegetation purposes in low-pH, metal-contaminated mine tailings, but it also demonstrates a method that can be used to address similar problems at other mine sites.

Nexus between Western and Chinese crude oil mining firms: An examination of modalities, practices, and socio-ecological ramifications

This study examines the operational methods, procedures, and socio-ecological impacts of Western and Chinese crude oil extraction industries, focusing on regional variations. Due to institutional dynamics, the study reveals distinct emissions patterns among state-owned sectors in China and the Western Union region. This was achieved by employing DID regression models, using a sample of 60 crude oil mining companies. Furthermore, the data demonstrates that intensifying research and development endeavors directly correlate with pollution reduction, indicating that technological advancements could foster a greater sense of environmental consciousness. Nevertheless, larger corporations emit more pollution, substantially utilizing resources and manufacturing. Both nations prioritize the government's role in reducing negative environmental impacts caused by pollution by implementing regulatory frameworks. Additionally, they focus on achieving long-term ecological sustainability through corporate social responsibility (CSR) initiatives. The paper suggests government involvement is necessary to enhance socio-ecological conditions at crude oil mining sites in Western and Chinese regions.

The Identification, Spatial Distribution, and Reconstruction Mode of Abandoned Mining Areas

The rehabilitation of abandoned mining sites is an increasingly pressing issue in the context of sustainable development. Recent research has emphasized the need for a holistic approach to the abandoned mining sites and their environmental rehabilitation. Based on field analysis, environmental assessments, satellite imagery processing and geographic information operations, this paper pushes forward the existing knowledge by conducting a comprehensive assessment of abandoned mining sites in the Romanian Carpathians and by proposing innovative and sustainable rehabilitation solutions. Our findings highlight that abandoned mining sites and their surrounding territories in the Romanian mountains have significant ecological imbalances and complex socio-economic issues. The findings also suggest that by adopting innovative, integrated, and sustainability-oriented approaches, territories affected by mining can be transformed into valuable and sustainable spaces to meet human needs. We conclude by presenting the importance of innovation in ecological reconstruction and spatial–functional reintegration of mining sites in mountain areas as a useful tool in making fair decisions, both in the context of implementing appropriate development policies as well as for the resilience and environmental sustainability of mining-affected mountain areas.

Comprehensive review of unmanned aerial vehicle application to safety mining management

The increasing interest of users in unmanned aerial vehicle (UAV) technology has developed new fields of application for it. Presently, UAVs are working in so many areas and the mining industry has shown grown interest in the use of UAVs for routine operations in surface, underground mines, and mine waste dumps. In this paper, a thorough review has been performed on the application of UAVs in mine safety management. Systematic reviews were conducted to summarize the results of over 60 papers published during the 2010-2021 period. The study offers a review of the most common applications involving mine safety, the styles of flying control, and the UAV types exploited. The paper also contributes to the identification of prevalent data acquired by sensors and points out the most popular processing techniques of aerial imagery. The obtained results revealed that UAVs are used at mining sites for safety purposes including mine surface displacements, stability monitoring, working environment, coal fire identification, drill and blast, and mine waste dump operations. This research hopes to provide a technical reference, expanding the knowledge and recognition of UAV monitoring to manage mine safety, as well as an assessment of applications in mining activities.

Regeneration of post‐mining and post‐fire soil function by assessment of tree nutrient status: Evidence from pioneer and N‐fixing species

AbstractNutrient concentrations in the foliage of particular tree species can identify growth‐limiting factors. Therefore, the adaptability and usefulness of certain trees in the afforestation of barren soils after disturbances could be based on nutrient supply and stoichiometry. In this study, we investigated the macronutrient supply to (i.e., nitrogen [N], phosphorus [P], potassium, sulfur, calcium [Ca], and magnesium [Mg]) and C:N:P (carbon:nitrogen:phosphorus) stoichiometry of the foliage of black alder (Alnus glutinosa), common birch (Betula pendula), and Scots pine (Pinus sylvestris) in two different regeneration scenarios—a reclaimed mine site with primary succession and an afforested post‐fire (PF) site with secondary succession. The control plot was on an undisturbed forest site hosting stands of the studied tree species. The lower concentrations of elements in the post‐mining soils developed from “point zero” were enough to supply the trees with a similar level of nutrition to those in the PF and undisturbed soils. The studied tree species differed in their foliage chemistry and had different effects on the soil properties. The alder and birch foliage contained more nutrients than the pine foliage. In particular, the birch foliage contained the highest concentrations of Ca, Mg, and P, thus enhancing the biogeochemical cycling of these elements. The alder foliage had the highest N concentration, albeit the soil total N contents under this species were not higher than those under birch. Thus, its phytomeliorative effect may have been overestimated. The pine foliage contained the lowest concentrations of nutrients, indicating the high nutrient use efficiency of this species. On the sites degraded after disturbance, pine and birch grew under N‐limitation stress, while the alder—a N‐fixing species—grew under P‐limitation stress, especially at the PF site. The PF soils under alder were also characterized by higher acidity, P depletion, and higher C:P and N:P ratios compared to the PF soils under the other studied species. We found that birch should be the most common tree species in the first phase of area regeneration after disturbances. Introducing alder into afforestation should take place in admixtures, especially at the PF site.

Sustainable valorization of mining waste: Phosphate sludge repurposing for advanced ceramic production

Managing the vast quantities of waste constantly generated by mining activities is one of the major environmental and economic problems facing mankind today. Fluorapatite is separated from the associated gangue minerals by a series of crushing and screening, washing, and flotation processes. These processes produce a significant amount of phosphate sludge, which is stored on the mine site in drift rock and large surface ponds. One possible environmental option is to reuse it as an alternative raw material in ceramics and building materials. Consequently, two phosphate sludges from two different Moroccan towns, Youssoufia and Khouribga, were studied. Due to the complexity of these raw materials resulting from long geological processes, in-depth physical, chemical, mineralogical, and thermal characterization is required. Dry compressed powder pellets were sintered at 900 °C, 1000 °C, and 1100 °C for 2 h. The study focuses on the effect of sintering temperature on mineralogical transformations and ceramic properties such as apparent porosity, water absorption, and mechanical strength. At 1100 °C, a slight increase in density was observed for both phosphate sludges. Water absorption was reduced by 2.51 % in both sludges for pellets sintered at 1100 °C compared to those sintered at 900 °C. Mechanical strength improved significantly, with an increase of about 60 % for samples sintered at 1100 °C, recording 227 N for Youssoufia sludge and 247 N for Khouribga sludge. This work has provided new data on the physical, chemical, mineralogical, and thermal changes in ceramics as the sintering temperature increases. These data will be useful for the manufacture of high-value ceramics.

Models Development for Prediction of Blast Efficiency and Total Charge in a Typical Quarry

The prediction of blast efficiency is usually achieved by using models; this in turn, gives better and more efficient rock fragmentation. However, the accuracy of the prediction often times relies on the model development validation. In this study, models were developed and compared upon validation for predicting the blast efficiency and total charge required for efficient fragmentation using artificial neural network (ANN). Rock samples were gathered from the study are, and the uniaxial compressive strength (UCS) test was carried out on all the samples based on international standard. The average UCS obtained from the rock samples at the Eminent quarry (EQ) is 153.61 MPa. The dimension of in-situ rock mass considered in the study area is 60 m x 40 m, and the in-situ block sizes obtained vary from 2.02 m2 to 3.20 m2. The average percentage value of F50 obtained from the Split-Desktop image analyses is approximately 72.44 cm. The various results obtained from the UCS, in-situ block size distribution, image analysis of the blasted rocks and the total charge were used to develop the models for the prediction of blast efficiency. The key issue of concern about these models is that they are mostly site specific and the fact that if they perform well in a location does not guarantee the other. Hence, the validation and suitability of these models on the mine site. The blast efficiency prediction using ANN is compared with measured efficiency and the value of coefficient of determination, R2 obtained is 0.9733. The value of the coefficient of determination, R2 obtained from ANN by comparing the prediction of the total charge and the measured total charge is 0.9773. The findings showed that, the proposed ANN based mathematical models are suitable and thus, give better prediction to blasting efficiency and the possible total charge.

Assessing soil contamination by potentially toxic elements in artisanal and small-scale gold mining sites of the Adamawa Region, Cameroon

Gold mining is acknowledged as a principal source of environmental contamination, primarily due to the release of potentially toxic elements (PTEs) through tailings dispersion into adjacent soils. Such contamination leads to land degradation, pollution, biodiversity loss and soil contamination, and subsequently impacts the food chain, human health and soil ecosystems. This study evaluates the extent of PTE contamination in soils at artisanal and small-scale gold mining (ASGM) sites within the Meiganga area of the Adamawa-Yade Domain, Cameroon. ASGM extraction processes from quartz veins in this area involve the removal of topsoil to access the ore. Comparative analysis of soil samples from three profiles within the mining zone were conducted to determine contamination levels using pollution indices: enrichment factor, geoaccumulation index, contamination factor and pollution load index. Results indicate higher concentrations of PTEs in soils from the mining area compared to the control profile, with notable contamination in the bottom slope profiles and B horizons, reflecting considerable metal accumulation. The contamination levels of PTEs substantially exceed background levels in the upper continental crust. The study attributes the elevated concentrations of PTEs not only to local mineralization but also to anthropic activities, particularly ASGM, which contributes to their enrichment, distribution and mobility. This pronounced contamination necessitates immediate intervention, advocating for pollution-control measures to address potential ecosystem and human health risks. It highlights the environmental toll of ASGM and underscores the imperative for sustainable mining practices and effective soil remediation techniques, including phytoremediation and soil replacement, to alleviate the adverse effects.