Artisanal Small-scale Gold Mining Research Articles

Mercury pollution in Peru: geographic distribution, health hazards, and sustainable removal technologies.

Peru is one of the great gold producers worldwide. However, a significant portion of the gold produced in Peru derives from artisanal small-scale gold mining (ASGM) in the Andes and Amazon. In ASGM, gold amalgamation with mercury (Hg) is a critical procedure to refine gold through the formation of Au-Hg alloys. Due to the rudimentary and improvised techniques conducted by small-scale and informal miners, Hg contamination has become of great concern and is strictly associated with ASGM. Multiple studies have evidenced notably high concentrations of Hg in consumable fish species, rivers, sediments, and air in locations where ASGM is one of the main sources of income to local communities and is carried out aggressively. In the present review, we have conducted a systematic search for national and international literature reporting the concentration and distribution of Hg pollution across environmental compartments, biota, and human samples in Peru. The results and data retrieved from the articles were quantitatively and qualitatively analyzed, and the distribution of Hg across environmental compartments was visualized through a geographic information system. Additionally, we reviewed the use of adsorption techniques as alternatives to treat Hg0 vapor from the gold shop and smelter flues, one of the main sources of hazardous levels of Hg exposure.

Environmental and Health Impact of Small-Scale Gold Mining Activities in Ibanda District of Uganda

In the recent past, artisanal small-scale gold mining activities in Kicuzi Subcounty, Ibanda District, Uganda, have had a severe influence on the environment and people's health. The study investigated the environmental and health impacts of small-scale. The questionnaires of 156 respondents were given to the Ibanda District's surrounding areas. The findings demonstrated that p-value is substantially associated with perception and the surroundings (p < 0.0005). The finding also demonstrates that p-value is substantially connected with the environment and health (p< 0.0005). The findings revealed that diarrhoea, skin illness, and injuries are the most common ailments in the population. As can be observed from the results, 75% of health workers admit that the health system in this municipality is not equipped to deal with mining-related health issues.

Atmospheric Hg Levels in Tree Barks Due to Artisanal Small-Scale Gold Mining Activity in Bunut Seberang Village in Indonesia

Mercury (Hg) is a useful heavy metal; however, it is toxic to both humans and the environment. Tree bark is an excellent bioindicator, which has been proven to be effective in studying the level of atmospheric Hg contamination. This study aimed to determine the distribution of evaporated Hg using the total weight of Hg (THg) in tree barks in Indonesia at the artisanal and small-scale gold mining (ASGM) area of Bunut Seberang Village and Lampung University, respectively. Samples were taken using purposive sampling, based on the criteria of forestry trees at a height level of 1.3 m above ground as wide as 100 cm2. The samples were analyzed by atomic absorption spectrometry and Scanning electron microscopy to determine the levels of THg and to investigate the bark structures. Results showed that the highest THg values were found in a Magnolia champaca sample (56.5 µg), followed by Swietenia mahagoni (45.8 µg) and Swietenia mahagoni (33.5 µg). All species studied showed THg levels in the tree barks at an elevation from 30 to 320 m above sea level. The Hg amounts found in the sampled barks indicated the dispersion of Hg throughout the ASGM area, which signified hazardous atmospheric conditions in the area.

Change Detection of Amazonian Alluvial Gold Mining Using Deep Learning and Sentinel-2 Imagery

Monitoring changes within the land surface and open water bodies is critical for natural resource management, conservation, and environmental policy. While the use of satellite imagery for these purposes is common, fine-scale change detection can be a technical challenge. Difficulties arise from variable atmospheric conditions and the problem of assigning pixels to individual objects. We examined the degree to which two machine learning approaches can better characterize change detection in the context of a current conservation challenge, artisanal small-scale gold mining (ASGM). We obtained Sentinel-2 imagery and consulted with domain experts to construct an open-source labeled land-cover change dataset. The focus of this dataset is the Madre de Dios (MDD) region in Peru, a hotspot of ASGM activity. We also generated datasets of active ASGM areas in other countries (Venezuela, Indonesia, and Myanmar) for out-of-sample testing. With these labeled data, we utilized a supervised (E-ReCNN) and semi-supervised (SVM-STV) approach to study binary and multi-class change within mining ponds in the MDD region. Additionally, we tested how the inclusion of multiple channels, histogram matching, and La*b* color metrics improved the performance of the models and reduced the influence of atmospheric effects. Empirical results show that the supervised E-ReCNN method on 6-Channel histogram-matched images generated the most accurate detection of change not only in the focal region (Kappa: 0.92 (± 0.04), Jaccard: 0.88 (± 0.07), F1: 0.88 (± 0.05)) but also in the out-of-sample prediction regions (Kappa: 0.90 (± 0.03), Jaccard: 0.84 (± 0.04), and F1: 0.77 (± 0.04)). While semi-supervised methods did not perform as accurately on 6- or 10-channel imagery, histogram matching and the inclusion of La*b* metrics generated accurate results with low memory and resource costs. These results show that E-ReCNN is capable of accurately detecting specific and object-oriented environmental changes related to ASGM. E-ReCNN is scalable to areas outside the focal area and is a method of change detection that can be extended to other forms of land-use modification.

Mercury Contamination: A Growing Threat to Riverine and Urban Communities in the Brazilian Amazon.

In recent decades, widespread and uncontrolled use of mercury (Hg) in artisanal small-scale gold mining has released thousands of tons of mercury-contaminated waste in the Amazon biome, endangering the largest tropical rainforest worldwide. In this study, we assessed and compared blood Hg levels in individuals living in urban and riverine areas in the lower Tapajós basin and examined the association between Hg exposure and specific biochemical parameters. In total, 462 adults from eight riverine communities and one urban area were assessed. Overall, 75.6% of the participants exhibited Hg concentrations exceeding the safe limit (10 µg/L). Hg exposure was higher in the riverine population (90%) than in urban areas (57.1%). Mean Hg levels were 21.8 ± 30.9 µg/L and 50.6 µg/L in urban and riverine residents, respectively. The mean Hg level was higher in those aged 41–60 years in both urban and riparian areas, with riparian residents exhibiting a mean double that of urban residents. The highest glucose and hepatic biomarker levels were detected in the urban area, whereas the highest levels of renal biomarker occurred in the riverine population. Our results indicate that Hg contamination remains a persistent challenge for the urban population of Santarém, a major city in the Brazilian Amazon.

Mercury Stories: Understanding Sustainability Through a Volatile Element

<i>Mercury Stories: Understanding Sustainability Through a Volatile Element</i>

Planning for the effective and sustainable management of Ghana’s artisanal small-scale gold mining industry

Over the years, artisanal small-scale mining (ASM) activities have been associated with unacceptable mining practices, which pose several health and environmental risks to communities and nations at large. Ghana is currently confronted with pollution of its main water bodies, which has reduced the supply of good quality water to the populace. To address these problems, several attempts - policy formulation, formalisation and introduction of technical assistance - have been undertaken by the government of Ghana and other international bodies such as United Nations Industrial Development Organisation-UNIDO. Despite these attempts, majority of artisanal small-scale miners are not registered and even some registered miners together with unregistered miners indulge in unacceptable mining practices. Premised on these, the study sought to undertake a thorough review of the challenges associated with the management of ASM in Ghana and provide a framework for the effective management of the sector. Consequently, a three-pronged approach (problem analysis, planning and implementation and enforcement) with a cross-cutting focus on monitoring and evaluation is recommended.

Implementation Effectiveness of Mercury Elimination Policies in Artisanal Small-Scale Gold Mining

This study evaluated the implementation effectiveness of mercury elimination policies in the Artisanal Small-Scale Gold Mining (ASGM) at Bolaang Mongondow District. A qualitative method used as an explanatory design through interviews and questionnaires. The data collected were analyzed using the Regulatory Gap Analysis method. Based on the data obtained, only 33% of respondents (community representatives) were aware of the mercury elimination policy. 75% of respondents (relevant agencies) have been aware of UU No. 11/2017 about the ratification of the Minamata Convention and the national action plan of the mercury elimination in gold processing in 2014-2018 ESDM (RAN-PPM PE 2014-2018 ESDM). 63% of respondents were aware of PP No. 21/2019 about the national action plan for reduction and elimination of mercury (PP 21/2019 RAN-PPM), and only 50% of respondents who were aware of PMK No. 57/2016 about the national action plan for controlling health impacts due to mercury exposure in 2016-2020 (PMK 57/2016 RAN-PDKAM). The average gap value based on the evaluation result of each policy was: -0.4 in RAN-PPM PE 2014-2018 ESDM, -0.24 in PP 21/2019 RAN-PPM, and -0.21 in PMK 57/2016 RAN-PDKAM. Therefore, the implementation of these policies is unsuccessful in overcoming mercury usage in the ASGM.

Assessing the suitability of convolutional auto encoder as an unsupervised tool for image classification in artisanal small-scale gold mining environment

Efforts to control or stop illegal Artisanal Small-Scale Gold Mining (ASGM) in Ghana, which is causing significant environmental degradation, have faced numerous challenges because these illegal activities are carried out in remote areas, inaccessible by the current practice of using 4WD vehicles or trekking by foot. This paper sought to assess the suitability of using an Unmanned Aerial Vehicle (UAV) to capture the locations and features of all ASGM sites and use a Convolutional Autoencoder (CAE) to classify the defined sites into legal and illegal ASGM sites. The classification process used by the CAE involved three main stages, namely encoding, latent space learning, and decoding. The encoder accepts the UAV captured images as input, processes the input images to extract salient features and the decoder decodes the salient features to reconstruct the input image and define a site as an ASGM site. To classify a defined ASGM site as legal or illegal, a python program was integrated into the CAE which makes use of known point coordinates of all legal ASGM sites. A site is flagged as illegal if its point coordinates do not match those in the legal ASGM sites database, otherwise, it is a legal site. The performance of the CAE was measured using the following performance metrics: accuracy, precision, recall, and FI-score. The results of the CAE proved superior giving a classification accuracy of 97.52% when compared with the results obtained from other classification algorithms, namely Random Forest (RF) and Support Vector Machine (SVM) with 93.23% and 95.66% respectively. In this paper, it has been demonstrated that UAVs can be used to capture the locations and features of all ASGM sites, which otherwise would have been inaccessible by the use of 4WD vehicles or trekking, and classify the captured location into legal and illegal ASGM sites using a CAE, to facilitate the control and prevention of illegal ASGM in Ghana.

Characterisation of Small-Scale Gold Mining Tailings in the Western Region of Ghana

On average, small-scale miners can recover gold ranging from 20% to 70% of the total available gold by the conventional gravity separation methods only. As a result of this, tailings materials from Artisanal Small-Scale Gold Mining (ASGM) operations contain a significant amount of gold, and characterisation of these materials would inform metallurgical decisions concerning reprocessing of the tailings from ASGM. In this study, size-by-size analysis, gold grade, gold deportment, and cyanidation studies were carried out on ASGM tailings samples collected from five different locations (Asankragua, Bogoso, Prestea, Wassa-Akropong, and Tarkwa) in the Western Region of Ghana. Head grades of tailings samples from Asankragua, Bogoso, Prestea, Wassa-Akropong, and Tarkwa were 1.84 g/t, 4.12 g/t, 0.45g /t, 0.17 g/t, and 5.97 g/t, respectively. The 80% (P80) of the tailings materials passed through 1.797, 0.578, 1.636, 3.210, 0.380 mm screen sizes for samples from Asankragua, Wassa-Akropong, Tarkwa, Prestea and Bogoso, respectively, with an average of 1.52 mm. Also, the gold deportment analysis revealed that the highest metal distribution of 42.03% in -106 µm size fraction for samples from Bogoso, followed by 31.0% for Wassa-Akropong, 29.7% for Tarkwa, 27.0% for Prestea, and 22.0% for Asankragua. It was shown after cyanidation test works that the highest gold recovery was 81.5%, 72.3%, 75.3%, 65.6%, and 38.5% for samples from Wassa-Akropong, Asankragwa, Prestea, Tarkwa, and Bogoso, respectively. Cyanidation can thus be employed to get higher gold recovery in ASGM.

Identification of mercury‐resistant Streptomyces isolated from Cyperus rotundus L. rhizosphere and molecular cloning of mercury (II) reductase gene

Streptomyces is one of mercury‐resistant bacteria which can convert Hg2+ into nontoxic Hg0 . This study aimed to identify mercury‐resistant Streptomyces present in the Cyperus rotundus rhizosphere from artisanal small‐scale gold mining (ASGM) area and clone merA gene to the cloning and expression vectors. Molecular identification was conducted using 16s rRNA gene with the maximum likelihood algorithms. Results revealed that the AS1 and AS2 strains were a group of Streptomyces ardesiacus and the BR28 strain was closed to Brevibacillus agri. The AS2 merA gene was cloned to pMD20 cloning vectors, pGEX‐5x‐1 and pET‐28c expression vectors. The transformation was successfully performed in BL21 and DH5α competent cells. The full length of the merA gene was confirmed to be 1,425 bp. This study is the first research on identifying mercury‐resistant Streptomyces and cloning the full‐length merA gene in Indonesia.

Dynamics of artisanal gold mining in Gashaka local government area of Taraba State, Nigeria

Despite the fact that gold has been mined in Gashaka, Taraba State for over a century and has continued to present day in the area, not much is known about this activity and its associated environmental impact in the state. This study therefore, examines the dynamics of artisanal small scale gold mining activities in Gashaka Local Government Area of Taraba State, Nigeria. The study adopted survey research design approach which involves the use of direct fieldwork observation and interview of key informants. The findings of the study reveals that alluvial gold is mined along the streams and farmlands on the floodplains in the area. The gold exists as alluvial gold dust and nugget gold. The artisanal gold mining activity is carried out with rudimentary materials such as pickaxes, diggers, shovels, spades, pans and water pumps. Some of the local mining communities are Gayam, Jamtari, Karamti, Serti, Goje, Bodel, Mayo Jim, Bashishir, Kurr and Garbabi. The 3 major methods employed by artisanal gold miners in the study area include panning method, use of locally constructed devices and picking of gold nuggets or crystals from dug pit on the floodplain. The artisanal gold miners use sulphuric acid and white mercury in purifying the collected gold. The miners do not use any protective gears such as face masks, rubber gloves, leather boots or head coverings in the mining process. All golds collected from the mining activities are sold in the town (Serti/Baruwa). There is a ready market with both local buyers residing in the town and distant buyers coming from different parts of the country. Artisanal gold mining is an important livelihood activity in the study area despite the fact that many of them are carried out illegally. Based on the findings, the study recommended the establishment of a goldsmith industry, improvement in security in the local communities and organizing the artisanal gold miners into cooperative organizations.

Examining Preference Heterogeneity in Best-Worst Scaling: Case of Preferences for Job Opportunities in Artisanal Small-Scale Gold Mining (ASGM) Communities in Indonesia

This research empirically examines the preferences for job-related attributes among rural villagers living close to artisanal and small-scale gold mining (ASGM) in Indonesia. Based on hypothetical scenarios in which a private company collaborates with the local government to establish a food processing industry in these villages, a questionnaire survey designed with best–worst scaling (BWS) was administered to households to determine their preferences. Additionally, the heterogeneity among the villagers was examined by applying a latent class logit (LCL) model. The main household survey was conducted in 2019 in Bone Bolango Regency, Gorontalo Province. The estimation results revealed that villagers are separated into four classes, and each class has different and unique preferences. Creating more job opportunities for society is a highly evaluated attribute; however, the preference for skill acquisition differs among groups. The results indicate that accounting for heterogeneous preferences regarding job opportunities is helpful to delink dependency on ASGM and health hazards and improve the livelihoods of rural villagers. The study yields key information to substantially reduce environmental and health hazards in the poverty-plagued ASGM community by facilitating job opportunities in Indonesia.

Economic Impacts on Human Health Resulting from the Use of Mercury in the Illegal Gold Mining in the Brazilian Amazon: A Methodological Assessment.

Artisanal small-scale gold mining (ASGM) in the Amazon results in the dumping of tons of mercury into the environment annually. Despite consensus on the impacts of mercury on human health, there are still unknowns regarding: (i) the extent to which mercury from ASGM can be dispersed in the environment until it becomes toxic to humans; and (ii) the economic value of losses caused by contamination becomes evident. The main objective of this study is to propose a methodology to evaluate the impacts of ASGM on human health in different contexts in the Brazilian Amazon. We connect several points in the literature based on hypotheses regarding mercury dispersion in water, its transformation into methylmercury, and absorption by fish and humans. This methodology can be used as a tool to estimate the extent of environmental damage caused by artisanal gold mining, the severity of damage to the health of individuals contaminated by mercury and, consequently, can contribute to the application of fines to environmental violators. The consequences of contamination are evaluated by dose-response functions relating to mercury concentrations in hair and the development of the following health outcomes: (i) mild mental retardation, (ii) acute myocardial infarction, and (iii) hypertension. From disability-adjusted life years and statistical life value, we found that the economic losses range from 100,000 to 400,000 USD per kilogram of gold extracted. A case study of the Yanomami indigenous land shows that the impacts of mercury from illegal gold mining in 2020 totaled 69 million USD, which could be used by local authorities to compensate the Yanomami people.

Effects of forest fires on mercury accumulation in soil at the artisanal small-scale gold mining.

In response to the Minamata Convention on Mercury, international organizations, governments, nonprofit organizations, and other institutions as well as individuals have worked to promote the development and implementation of safe and environmentally healthy practices, processes, and products. It is expected that the accumulation of mercury in the natural environment will decrease in volume each year. However, even after Hg ceases to be used, the Hg already accumulated in forests will continue to pose an ecological risk. Forest fires are serious events, partly because they release accumulated Hg from the environment. In this study, the effects of forest fires on the accumulation and chemical species of Hg in soil, related to the mobilization of Hg, were investigated. The research was conducted in secondary forests located near artisanal small-scale gold mining sites, where Hg is used for the amalgamation of gold in Camarines Norte, Philippines. The results showed that the original Hg accumulation level in the burned forest was not as high as that in the control forest, and that burn severity might have affected only the surface soil (0-5cm). However, the proportion of water-soluble Hg, which was derived from ash, was increased by fire. Therefore, it is suggested that forest fires not only increase the release of Hg into the atmosphere but also increase the outflow risk to the aquatic system through rainfall.

Mercury Emissions from Artisanal Small-scale Gold Mining (ASGM), Primary Iron and Steel Production, and Techniques for Countermeasures

Mercury Emissions from Artisanal Small-scale Gold Mining (ASGM), Primary Iron and Steel Production, and Techniques for Countermeasures

Socio-environmental perceptions and barriers to conservation engagement among artisanal small-scale gold mining communities in Southeastern Peru

Artisanal small-scale gold mining (ASGM) poses threats to biodiversity and to the health and well-being of human communities. However, ASGM also economically supports several populations from lower social-economic backgrounds, especially in the Global South. In Madre de Dios (MDD), Peru, ASGM is the most significant economic activity, involving several stakeholders form different levels of governance. To protect this area’s forests and aquatic systems from further degradation, it is necessary to understand the socio-economic background and the impediments to mining formalization, as well as the local perceptions and willingness to engage in conservation. In this study, we aimed to establish the drivers of and barriers to participation in environmental conservation among communities in MDD, which economically rely on ASGM. Using a mixed method approach, we surveyed 85 households in six communities in the MDD gold corridor. Half of participants were cognizant of the effects of ASGM and concerned about deforestation and local decreases in fish and wildlife abundance, declaring willingness to take part in environmental conservation. Native participants in particular expressed concern about land degradation and the action of immigrants. However, several participants reported feeling alienated by government institutions and raised doubts about the intentions of non-governmental conservation organizations, and the purpose of protected areas. Participants in general felt that ASGM-related policies were not realistic and bureaucratic barriers were raised to prevent formalization. Our findings suggest that current policies and communication strategies may hinder efforts to transform relatively prevalent pro-environmental attitudes into matching behaviors, including participation in conservation initiatives. To achieve this goal, more efficient communication and more active involvement of local stakeholders in mining governance and conservation planning are necessary.

The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution

Abstract. Nur I, Aris EA, Yusnaini Y, Beavis S. 2021. The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution. Biodiversitas 22: 3764-3772. Artisanal small-scale gold mining and the use of mercury is widespread across Indonesia, often characterized by relatively short-lived gold rushes. In the late and post-mining phases, mercury stored in mine tailings and river beds was transported down catchment, posing risks to ecosystems and human health over much longer time scales. These risks can be under-rated when mercury concentrations in water, sediments, and aquatic species are low enough to meet relevant guideline thresholds. In this study in Southeast Sulawesi, Indonesia, we have investigated the Costraca barnacle, Octolasmis, as a bioindicator of mercury contamination. The presence of Octolasmis parasites in mud crabs, Scylla spp., and the accumulation of mercury (Hg) in the hosts, parasites, and the ambient environment, were analyzed across both dry and wet seasons. Severe infestation of Octolasmis was assessed using prevalence, abundance, and intensity. Hg concentrations were significantly higher in the Octolasmis parasites than in the host tissues, water and sediments. The mean bioconcentration factor (BCF) of Hg equaled 7938.21 from water to parasites, and 28.91 from the host’s gill tissue to the parasites. The results suggest that Octolasmis spp. can be used effectively as a bioindicator in coastal catchments impacted by mercury contamination, even when concentrations of mercury are low in water and river sediments. The study provides the first report of Octolasmis spp. parasitized to mud crabs as a reliable bioindicator of Hg contamination and pollution.

Sustainability of the Artisanal and Small-Scale Gold Mining in Northeast Antioquia-Colombia

The aim of this work is to explain the concepts of sustainability with respect to small artisanal gold mining. For this, a qualitative approach with a descriptive scope was used, for which the bibliographic review technique was conducted. In this sense, articles, theses, books and institutional documents, and any contribution related to the research topic were taken into consideration. Likewise, this documentation contributed to the delimiting aspects that allowed a contrast between the proposed definitions and small artisanal mining in the Northeast Antioquia region in Colombia. Based on the reviewed sources, different needs were recognized in artisanal small-scale gold mining in Northeast Antioquia that still need action. In conclusion, through the exposition of sustainability theories, three common factors were identified within the various positions that were raised—the environmental, economic, and sociocultural dimensions.

The politics of artisanal small-scale gold mining (ASM) in the Akyem Abuakwa Traditional Area of Ghana

ABSTRACT This paper explores the power relations and institutional arrangements that shape Ghana's artisanal small-scale gold mining industry. Using the Akyem Abuakwa Traditional Area in the Eastern region as a case, the paper relies on in-depth interviews of key informants including officials of relevant local government institutions, members of the traditional authority and selected small-scale miners, to gather evidence of socio-political relationships and power dynamics. The study also adopted focus group discussions; transect walks and field observations to explore the perceived breaches by small-scale mine operators and how these are influenced by power relationships at national and local levels. The study finds complex power relationships that make artisanal small-scale mining (ASM) unsustainable. Innovative and participatory interventions have been proposed to ensure the effective enforcement of existing mining and environmental protection policies and laws.