Artisanal Gold Mining Research Articles

A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining

Mercury amalgamation is the method of choice to recover gold in artisanal and small-scale gold mining (ASGM). However, despite the low cost and simplicity of this method, the use of mercury presents serious health and environmental risks, as well as low efficiency in gold extraction. This study investigates the application of cyanide and thiosulphate leaching as alternatives to mercury amalgamation. This investigation was undertaken by conducting leach experiments using cyanide at 1 g/L, 3 g/L, and 5 g/L, and ammonium thiosulphate at 0.1 M and 0.5 M, on three ore samples originating from an artisanal mining area in Zimbabwe. The operating conditions (T = 26 °C, solids loading: 30%, particle size: −300 + 150 µm) were selected to mimic as closely as possible the conditions of artisanal mining processes. It was found that cyanide leaching was the better performing technology compared to thiosulphate leaching, as it achieved gold extractions of 71.6%, 69.7%, and 67.8% for the three ore samples (Sample 1, Sample 2, and Sample 3, respectively), whereas thiosulphate leaching achieved gold extractions of 54.1%, 35.6%, and 38.0% for the three ores, respectively. Both methods outperformed mercury amalgamation, which typically achieves gold recoveries of 30%–50%. Studying the minerology of the ores, using XRF, XRD, QEMSCAN, SEM-EDS, and a diagnostic leach, revealed the presence of sulphide minerals hosting refractory gold which contributed to the low gold extractions observed. Besides achieving higher gold extraction, cyanide leaching proved to be a system that is easier to control compared to thiosulphate leaching, making it much more attractive to artisanal miners.

Mercury mitigation and unintended consequences in artisanal and small-scale gold mining

The increased research attention on estimating the global mercury use and emissions in artisanal and small-scale gold mining (ASGM) has improved awareness of the problems associated with ASGM. However, little attention has been paid to the specific effects of particular intervention strategies to mitigate global mercury use and emissions in accordance with the Minamata Convention on Mercury. In this study, we examine the effect of each type of intervention (concentrate amalgamation, use of a retort, and the cyanidation technique). The results show that, despite the massive reduction in mercury emissions associated with the implementation of the retort and cyanidation technique, these interventions created new critical issues. As unintended outcome of these interventions, there has been a significant increase in the quantity of global mercury which needs to be properly and permanently managed as a waste (< 1740 Mg in 2050) and also in global hydrogen cyanide emissions (< 46,700 Mg in 2050). The findings of this study indicate that, when taking these measures alone, efforts to mitigate mercury use and emissions in accordance with the Minamata Convention on Mercury generate different risks which, in effect, jeopardize sustainability in ASGM. Comprehensive mercury mitigation strategies which also consider these unintended consequences should be included in the action plans adopted by policymakers at the national level.

Preponderance of vaccine-preventable diseases hotspots in northern Ghana: a spatial and space-time clustering analysis from 2010 to 2014

BackgroundVaccine-preventable diseases (VPDs) persist globally with a disproportionately high burden in Low and Middle-Income Countries (LMICs). Although this might be partly due to the failure to sustain vaccination coverage above 90% in some WHO regions, a more nuanced understanding of VPD transmission beyond vaccination coverage may unveil other important factors in VPD transmission and control. This study identified VPDs hotspots and explored their relationships with ecology, urbanicity and land-use variations (Artisanal and Small-scale Gold Mining (ASGM) activities) in Ghana.MethodsDistrict-level disease count data from 2010 to 2014 from the Ghana Health Service (GHS) and population data from the Ghana Population and Housing Census (PHC) were used to determine clustering patterns of six VPDs (Measles, Meningitis, Mumps, Otitis media, Pneumonia and Tetanus). Spatial and space-time cluster analyses were implemented in SaTScan using the discrete Poisson model. P-values were estimated using a combination of sequential Monte Carlo, standard Monte Carlo, and Gumbel approximations.ResultsThe study found a preponderance for VPD hotspots in the northern parts of Ghana and northernmost ecological zones (Sudan Savannah and Guinea Savannah). Incidence of meningitis was higher in the Sudan Savannah ecological zone relative to: Tropical Rain Forest (p = 0.001); Semi Deciduous Forest (p < 0.0001); Transitional Zone (p < 0.0001); Coastal Savannah (p < 0.0001) and Guinea Savannah (p = 0.033). Except for mumps, which recorded a higher incidence in urban districts (p = 0.045), incidence of the other five VPDs did not differ across the urban-rural divide. Whereas spatial analysis suggested that some VPD hotspots (tetanus and otitis media) occur more frequently in mining districts in the southern part of the country, a Mann-Whitney U test revealed a higher incidence of meningitis in non-mining districts (p = 0.019). Pneumonia and meningitis recorded the highest (722.8 per 100,000) and least (0.8 per 100,000) incidence rates respectively during the study period.ConclusionThis study shows a preponderance of VPD hotspots in the northern parts of Ghana and in semi-arid ecoclimates. The relationship between ASGM activities and VPD transmission in Ghana remains blurred and requires further studies with better spatial resolution to clarify.

High Environmental Radioactivity in Artisanal and Small-Scale Gold Mining in Eastern Democratic Republic of the Congo

The radioactivity associated with artisanal and small-scale gold mining activities (ASM) carried out along the Ulindi River, in the eastern Democratic Republic of the Congo, was evaluated by gamma-ray spectrometry and inductively coupled plasma–mass spectrometry of soil and sediment samples. The results revealed that activity concentrations of 238U (up to 3127 ± 98 Bq kg−1), 226Ra (up to 2710 ± 89 Bq kg−1) and 232Th (up to 2142 ± 162 Bq kg−1) were 71- to 89-fold higher than the worldwide average concentrations reported by UNSCEAR in soils. Primordial radionuclides are, thus, present in high concentrations in deposits of gold in that region and the average ambient effective radiation dose rate was determined at 8.4 mSv y−1 (range 0.5 to 40 mSv y−1). This area may be classified as a natural high background radiation area (HBRA). The radiation risk for artisanal miners and population members manipulating those geological materials were assessed through radiological parameters. such as the radium equivalent activity index (RaEq), outdoor gamma absorbed dose rate (ODRA), annual effective dose equivalent (AEDE), and excess lifetime cancer risk (ELCR). The mean values of these parameters were significantly elevated in comparison to the world average levels and indicated the existence of significant radiation risks for gold miners and members of the local population. A radiation safety policy seems needed to protect workers and the local population in this region.

Assessment of blood mercury, immune response, heat shock and oxidative stress marker in free-ranging chicken (Gallus Gallus domesticus) from gold mining areas in Zamfara State, Nigeria

We investigated serum mercury, immune response, heat shock and oxidative stress marker in free-ranging chicken (Gallus Gallus domesticus) from Artisanal and small-scale gold mining (ASGM) areas. Six groups were created from sixty free-ranging chickens (Gallus Gallus domesticus), three each from ASGM and non-ASGM areas. Immune response, heat shock and oxidative stress markers were analysed, and multivariate and univariate data analysis were used to discriminate the difference in the study group. Results revealed a significant increase in serum mercury (Hg) from chicken in ASGM areas. Superoxide dismutase, glutathione peroxidase (GPx), glutathione (GSH), catalase and total antioxidant capacity significantly decreased, while lactic acid dehydrogenase and malondialdehyde (MDA) content significantly increased in animals from ASGM areas. A unit increase in GPx and GSH significantly corresponds to a decrease in serum Hg by 0.001 μg/mL and 0.206 μg/mL, respectively. While a unit increase in MDA significantly corresponds to an increase in serum Hg level by 0.003 μg/mL. The activities of HSP-70, TNF-α, IL-1β and IL-6 were significantly higher in the serum of chicken from ASGM areas. All significance at p < 0.05. ASGM activities result in mercury bioaccumulation with potential health effects caused by dysregulated immunity, heat shock and oxidative stress.

Taming air and water: The fight against shimoke in artisanal and small-scale gold mining in South Kivu

How do miners in South-Kivu tame air and water in the underground? And in doing so, how do they manage and moderate leaks that creep into their mining gear? In this article, we use the so-called shimoke, deadly, invisible, and odorless fumes that exude from a small water pump, as an ethnographic entry-point to engage with these questions. In doing so, we weave a story that meanders and traces engagements from the import of mining gear under colonial rule to current underground attunements and aboveground socio-technical engineering.

Human risk assessment of ash soil after 2020 wildfires in Pantanal biome (Brazil)

Wildfires have increased in the last years and, when caused by intentional illegal burnings, are frequently run out of control. Wildfire has been pointed out as an important source of polycyclic aromatic hydrocarbons (PAHs) and trace elements (TEs) — such as, As, Ni, and Pb — to environmental compartments, and thus may pose a risk to human health and to the ecosystem. In 2020, the Brazilian biome, Pantanal, faced the largest losses by wildfires in the last 22 years. Ashes from the topsoil layer in Pantanal were collected after these wildfires at 20 sites divided into the sediment, forest, PF, PS, and degraded sites. Toxicity and associated risks for human health were also evaluated. The areas highly impacted by wildfires and by artisanal gold mining activities showed higher concentrations for TEs and PAHs than the protected areas. Pb varied from 8 ± 4 to 224 ± 81 mg kg−1, and total PAH concentration ranged between 880 ± 314 and 1350 ± 70 ng g−1, at sites impacted by anthropogenic activities. Moreover, health risk assessments for TE and PAH indicated a potentially great risk for children and adults, via ingestion, inhalation, and dermal pathway. The carcinogenic risks exceeded reference values, for both TE and PAH, suggesting harmful conditions, especially for vulnerable groups, such as children and the elderly.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11869-022-01248-2.

Appropriate technologies and the geosocial evolution of informal, small-scale gold mining in Madre de Dios, Peru

This article examines the evolution of gold extraction and processing technologies used in artisanal and small-scale gold mining (ASGM) in the Amazonian region of Madre de Dios, Peru. Beyond demonstrating a historical evolution in technologies, I discuss how differentiation in gold production practices has important implications for the governance of gold mining. Proposals by policymakers to reform ASGM into a more environmentally sustainable sector often obscure the differences in gold production practices within particular mining localities. A common intervention is aimed at replacing certain technologies like mercury amalgamation – commonly used in ASGM - with alternative technologies. However, as I argue in this article, the promise of cleaner gold production through adoption of alternative technologies ultimately fails to recognize how and why diverse modalities of gold production have evolved over time. I demonstrate how in Madre de Dios, diverse gold production modalities have evolved as a response to site-specific geological conditions, differences in miners’ access to capital, and a changing socio-political landscape. Putting my findings into conversation with current policy proposals, I argue that flexible governance approaches that account for heterogeneity in gold production practices and socioeconomic differentiation amongst operators, are more likely to succeed than one size fits all approaches.

Capitals in artisanal and small-scale mining in Marmato, Colombia: Using the sustainable livelihoods framework to inform formalization

This paper applies the concept of capitals in the sustainable livelihoods framework (SLF) to examine artisanal and small-scale mining livelihoods in the municipality of Marmato, Colombia and discusses the relevance of these findings to formalization efforts. Artisanal and small-scale mining (ASM) is an important and often traditional livelihood in the rural global south where income generating alternatives are scarce. Marmato is one of South America's oldest gold mining sites, and ASM has been intermittently practiced there since about 500 B.C. The present study maps ASM onto the five capitals of the SLF and identifies several forms of capitals that miners cited as the most relevant for pursuing ASM activities. The results show that artisanal and small-scale gold miners in Marmato strategically combine different forms of capital that enable them to make a living from mining; however, there are key factors that may impact the longer-term viability of artisanal and small-scale mining livelihoods. Although human, social, and financial capital function to support ASM livelihoods, the finite nature of natural capital and deterioration of physical capital erode the potential for sustainability of those livelihoods. This research highlights the utility of closely examining the capitals in the SLF and suggests that a more comprehensive understanding of ASM capitals can better inform formalization policies and associated development interventions.

Productivity and profitability: Investigating the economic impact of gold mining mechanisation in Kamituga, DR Congo

In South Kivu Province of the eastern Democratic Republic of the Congo, the use of new technologies in artisanal and small-scale gold mining (ASGM) has proliferated over the course of the last decade. Based on a case study of ASGM mechanisation in the major mining town of Kamituga, we investigate the economic impact of this process on the productivity of ASGM and the profitability of its operations. Drawing on a wide range of qualitative and quantitative data, we challenge the common perception of ASGM as traditional, conservative, and unproductive. We demonstrate that on the contrary, ASGM operators in Kamituga make use of sophisticated and productive machinery in their quest to profit from their activities. With the recent emergence of ball mills and other forms of mining technology, gold production in Kamituga now carries a distinctly 'small-scale' character.

Artisanal and small-scale mining methods and the Sustainable Development Goal 6: Perceived implications for clean water supply

This paper aims to examine methods of artisanal and small-scale mining (ASM) in Ghana, map their perceived impacts on water resources, and analyse the implications of these perceptions for meeting the targets related to Clean Water of the United Nations Sustainable Development Goal 6 (SDG 6). The paper draws on 74 interviews with artisanal and small-scale gold miners and other stakeholders to investigate communities’ perceptions of the effects of ASM methods (alluvial mining, surface/open-pit mining, and underground mining) on water bodies. We find that different ASM methods impact surface and groundwater in distinct ways while concurrently having a synergistic negative effect on water bodies. Stakeholders – including community leaders – perceive that the mining methods employed in ASM cause various forms of environmental degradation – thus affecting progress towards SDG 6, target 6.3 (water quality) – and severely hinder the availability of clean water for domestic and agricultural purposes, thus endangering the livelihoods of communities and affecting progress towards SDG 6, target 6.4 (sustainable water use). The community perceived impacts of ASM activities on water resources have implications for community acceptance of formalisation efforts in Ghana. We contend that a better understanding of these perceived impacts can help shape the country’s policy for achieving the targets of SDG 6 in relation to Clean Water by 2030. In particular, we propose that the integration of the Community Mining Scheme as part of formalisation efforts of informal gold mining in Ghana not only responds to SDG 6 target 6b (participation of local communities in water management) but also has the potential to reverse the current large-scale mining ‘bias’ in policy, while addressing the galamsey challenge that contributes to the increasing impact of informal gold mining on SDG 6, targets 6.3 and 6.4.

“We are mine workers”: Feminists’ political economy in artisanal and small scale gold mining in the Talensi District, Ghana

This article aims at exploring the social and political elements in women’s practices in artisanal and small-scale mining (ASM) in the Talensi District in Ghana. This study draws on feminist political economy literature to investigate how women exercise agency in this maledominated industry to carve out spaces for participation. In addressing how women exercise agency, this study examines the structural constraints of women in ASM and women’s practices to overcome those constraints. Although women take part in limited, unremunerated activities in the ASM industry, this study moves beyond socioeconomic dynamics into rethinking sociopolitical practices in ‘unmonitored’ spaces. This study employed ethnographic methods of participant observation, focus group discussions, voice-recorded semi-structured interviews, extensive field notes, and immersion in women’s work as miners to collect data in the Talensi mining area. The participants of this study were selected based on residence at the mines, interest to respond to the questions and motivation to be part of the study. Altogether, forty women with an average age of 40 years and eight men with an average age of 35 years were interviewed. Data analysis comprised a six-phase guide theoretical and thematic framework. The findings of the study noted that women’s work practices, organization and roles in the male-dominated ASM industry provide a clear picture of innovative and skillful actors. Women proactively engage in practices that promote their ability to carve spaces for participation. For example, women employ ethnicity as a tool to recruit other women into the industry. In conclusion, despite structural constraints in the small-scale mining industry, women create spaces in the substructures of the industry to negotiate for better remuneration and leadership roles, exercising their individual and collective agency. This study recommends that any programs and policies on ASM in Ghana should promote women’s proactive participation and contribution to the industry.

Framing illegal artisanal and small-scale gold mining in the Ghanaian media during the #StopGalamsey campaign

AbstractArtisanal and small-scale mining (ASM) plays a significant socio-economic role in the alleviation of poverty. In Ghana, the increase in and persistence of illegal ASM (galamsey) can be explained by unemployment, cumbersome and costly registration, lack of land, corruption and Chinese engagement. Traditionally, Ghanaian governments have neglected to address ASM activities by means of policy, while publicly emphasizing its negative impacts. In 2017, the media campaign #StopGalamsey became a culmination of this process. This study represents a qualitative content analysis of #StopGalamsey media discourses. It aims to understand how galamsey was framed in the media during the first two years of the campaign. Based on an analysis of 176 articles from the Daily Graphic newspaper, four dominant frames were identified – environmental menace, criminal activity, complex menace and corruption and collusion. Galamsey was portrayed in an overwhelmingly negative way, miners were dehumanised and criminalised, conflicting perspectives marginalised, and non-traditional perception emphasised via Chinese engagement.

Water pollution and environmental policy in artisanal gold mining frontiers: The case of La Toma, Colombia

Artisanal and small-scale gold mining (ASGM) is the largest anthropogenic source of mercury emissions globally. Concern over mercury pollution increases due to its long-term impacts on human health and aquatic and terrestrial ecosystems. Using a participatory research methodology, we gathered social and behavioral information regarding daily practices and water usage by an ASGM community in Suárez, Colombia. Based on this information, we identified 18 sampling sites of water sources commonly used by the community. The samples were analyzed for total mercury, total coliforms, pH, electrical conductivity, and total dissolved oxygen. Physicochemical and microbiological parameters from the water assessment were compared with the drinking water thresholds set by the Colombian regulatory agencies, the EPA, and the WHO. Our results showed that the majority of the samples do not meet one or more quality and safety standards. On average, the sampling sites showed total mercury levels below the regulatory limits; however, the data had considerable variability, and in many cases, individual observations fell above the maximum concentration limit for drinking water. We discuss these results within the larger framework of the regulatory gaps for human and environmental protection in ASGM contexts. The total lack of water, sanitation, and hygiene infrastructure, combined with the long-term consumption of sublethal doses of mercury and other water contaminants, constitutes a significant threat to the well-being of communities and territories that necessitates further research and intervention by institutional authorities.

Women who “age too fast”: Female work, bodies and health in the gold mines of Eastern Democratic Republic of Congo

Mining activities have particular effects on women's health, but these effects have hardly been documented in the literature. This article fills the gap by focusing on women's lived experiences in artisanal and small-scale gold mining (ASGM). Based on interviews with more than 150 women working in the mines in the city of Kamituga, eastern Democratic Republic of Congo (DRC), we illustrate how women feel the impact of their work on their bodies and reflect on how this impact could be mitigated. We analyse women's lived experiences in terms of the most common infectious diseases, as well as physical and psycho-social trauma. We argue that ASGM has gendered effects on the workforce's health and that, to better protect female workers, we need to take a holistic approach to their health problems and address structural constraints.

Mercury pollution assessment and metallothionein gene expression in tilapia (Oreochromis mossambicus): a case study of Revuè River in Manica, Mozambique

Revuè River has been considered as one of the most threatened systems in Mozambique due to increased anthropogenic activities such as artisanal and industrial gold mining using mercury (Hg), a heavy metal known for its diverse effects including, bioaccumulation and biomagnification in the environment. The present study aims to determine the metallothionein (MT) expressions in the hepatic tissue of Oreochromis mossambicus (tilapia) exposed to Hg in the laboratory and tilapia collected in Chicamba reservoir. Tilapia juveniles were exposed to different concentrations of Hg (0.037 and 0.37 mg/L) in the laboratory. Water, sediment and fish samples were collected to quantify Total Hg (THg). Furthermore, liver samples in tilapia exposed to Hg and tilapia samples from Chicamba reservoir were collected to analyze the gene expression levels of MT using a quantitative PCR. Results from the study showed a low contamination of the waters and sediment from Revuè River, demonstrated by the Hg concentration in the sediment and water. Slightly high concentrations of Hg were detected in fish from Chicamba reservoir, confirmed by the overexpression of MT observed in liver samples from tilapia and were higher than those expressed in tilapia from the laboratory experiment. There is a correlation between Hg exposure and the MT expression in tilapia, suggesting that MT can be used as a biomarker to assess Hg pollution in the Revuè River.

Monitoring Coexisting Rapid Small-Scale and Large-Scale Gold Mining Developments Using Planet Smallsats Constellations

Gold mining is a significant strategic sector for local, regional, and national economies. The rapid development of coexisting camp-type artisanal and small-scale gold mining (C-ASGM) and large-scale mining (LSM) accelerates the environmental and health risks associated with mercury pollution; however, transformations of coexisting sites have not been well quantified. This study used remote sensing (the PlanetScope smallsat constellations systems) to investigate the development of coexisting C-ASGM and LSM sites in Gorontalo, Indonesia, from 2019 to 2022. The results show a positive increase in the extent of barren land across all study zones, resulting from a road network construction connecting the southern port to major mining sites. Notably, greater landcover transformations in the C-ASGM sites after 2020 were attributed to the dumping of underground soils excavated using a shaft-mining method. The findings of this study expand our understanding of the rapid development of coexisting mining operations and quantify significant mining-induced environmental changes. These findings are anticipated to assist in timely monitoring and identification of development areas, rates, and volumes, together with the existing C-AGSM’s reactions associated with LSM’s massive developments. This also helps to detect possible local-level socioenvironmental impacts from massive land shape changes, leading to human disasters, including landslides and floods.

Work regimes and technology-driven transformations in DRCongo's artisanal and small-scale gold mines

Over the past two decades growing scarcity and rising costs have pushed artisanal and small-scale gold miners all over the world towards mechanization and technological innovation. Based on qualitative data gathered in the two largest artisanal and small-scale gold mining (ASGM) towns in South Kivu province, eastern Democratic Republic of Congo (DRC), we analyze what these technological innovations imply for the ASGM work regime, conceptualized as the set of practices used to organize and control workers. We observe transformations in workers’ tasks, skills and specializations; a reorganization of working time and space; an evolution in the payment system towards wage labour; a concentration of financial capital; and a strengthening of the position of mining cooperatives. We also stress the embedded and sedimented nature of these transformations.

Assessment and Awareness of Health Risks Posed by Mercury in Artisanal Gold Mining in the Ashanti Region of Ghana

Assessment and Awareness of Health Risks Posed by Mercury in Artisanal Gold Mining in the Ashanti Region of Ghana

Peruvian Native Bacterial Strains as Potential Bioremediation Agents in Hg-Polluted Soils by Artisanal Mining Activities in Southern Peru

Bioremediation of soils and waters due to mercury (Hg) contamination represents one of the most critical environmental challenges. In addition, this challenge is even greater in arid soils due to the low economic interest in these regions. Such is the case of the Secocha Annex, located in the Arequipa province of Camaná in Southern Peru. In this region, the excessive use of Hg in artisanal and small-scale gold mining (ASGM) activities has seriously endangered the health of its inhabitants. Unfortunately, there are few projects aimed at improving the environmental and sanitary conditions of this locality. An alternative to conventional cleaning technology is the use of native microorganisms that allow the recovery of ecological environments with low-cost and low-tech techniques. This work aims to present two new Hg-resistant bacterial strains obtained from Hg-polluted soils of the Secocha Annex as potential bioremediation agents. Both strains showed growth capacity on Hg substrates and their adsorption behaviors and Hg removal capacities were evaluated. By deoxyribonucleic acid (DNA) analysis, both Gram-positive strains were identified as Kocuria sp. (99.35% similarity) and Zhihengliuella sp. (99.78% similarity). Spectrometry results showed elimination capacities with values close to 28.4 and 33.3 % in an incubation time period of 45 days, with the maximum elimination efficiency in the first 24 h. These results are encouraging and offer new possibilities for the use of native strains in the bioremediation of arid soils contaminated with Hg in the Secocha Annex. Furthermore, due to the low cost and minimization of negative impacts, this technique and our bacterial strains could be used in other regions of Peru.