Land Use and Land Cover Dynamics in the Eseka Alluvial Gold Mining District, Centre Region, Cameroon

Local populations in Cameroon thrive on forest resources and the flow of ecosystem services they provide are pivotal in sustaining national economy, improving people’s lives, safeguarding biodiversity, and mitigating the impacts of environmental changes. The exploitation of these resources invariably leads to deforestation and forest degradation. This study was designed to evaluate land use land cover change (LULCC) in the Eseka alluvial gold mining district with the aid of Landsat images. In the investigation of forest cover change, four Landsat satellite images for (1990, 2002, 2015 and 2022) were used. Ground-truthing also helped to identify the activities carried out by the local population and to determine agents, drivers and pressures of land use and land cover change. Four main land cover classes namely: forest, agricultural land, settlement/mining camps and water bodies were selected. Between 1990 and 2022, the proportion of forest decreased from 98% to 34% while those of agricultural land and settlement/mining camps increased from 2% to 60% and 0.54% to 6% respectively. Analysis showed ongoing deforestation with forest cover loss of ~98,263 ha in 32 years giving a cover change percentage of 63.94%. Kappa coefficient for the study period ranged from 0.92 to 0.99. Forest cover loss could be attributed to farming activities, wood extraction and alluvial gold mining activities. Economic motives notably the need to increase household income from a frequent demand for farm and wood products in neighbouring towns and the quest for gold were the main drivers of these activities. Hence, this study assesses the impact of human activities from the mining sector on the forest ecosystem in a bid to inform mitigation policies.

Development and Application of Water Quality Index (WQI) for the Evaluation of the Physico-Chemical Quality of Groundwater in Gold Mining Areas of Southeastern Senegal

Water is the most essential requirement for life. It provides a variety of purposes such as a source of water supply for drinking, domestic and industrial use, irrigated agriculture, livestock, and mining activities. Evaluating the status of water quality from traditional approaches does not guarantee the whole overview of the water quality situation. Therefore, developing a tool that can convert multiple parameters data into information that is understandable by both technical and non-technical personnel is vital. In this context, the purpose of this paper was to develop, calculate, and apply a water quality index for assessing the suitability (for drinking purposes) of groundwater in the gold mining areas in south-eastern Senegal. The development of this index based on WHO water quality guidelines followed the five standards steps i.e., parameters selection, sub-index formation, parameters weighting and sub-index aggregation and evaluation. Finally, the WQI summarized twelve key water quality parameters into 05 simple terms (excellent, good, medium, poor, and very poor) which is more relevant for reporting to managers and the public in a consistent manner. Thus, it was observed in the study area, that the water quality indexes in artisanal and industrial mining areas are either poor or very poor while in the reference stations (where there are no mining activities) WQI are either good or excellent. This situation was attributed to the effects of mining activities in such zones which contribute to the pollution of groundwater with heavy metals, nitrates, and suspended solids.

Evaluation of ecological risk and primary empirical research on heavy metals in polluted soil over Xiaoqinling gold mining region,Shaanxi,China

Soil,crop and residents'hair over Xiaoqinling gold mining region,China,which was selected as a case study,were sampled and analyzed for Hg,Cd,Pb,Cu,Cr,As and Zn concentrations.The concentrations of heavy metals in soil or crop and hair samples were used to assess their potential ecological risks,or to find the responses to these metals as evidences to prove the potential risk was coming down to observed harm,respectively.The results showed that,these metals in soil were ranked by severity of ecological risk as Hg>Cd>Pb>Cu>Cr>As>Zn,based on their single-element indexes.In the view of the potential ecological risk indexes,of all soil samples,about half had significantly high or high potential ecological risk,which covered more than 74%of the studied region.Most of the risks were 97.41%from Hg,Pb and Cd,especially,84.37%from Hg.Both the single-element and potential ecological risk indexes indicated that,the ecological risk grades had a special spatial characteristic,and increased from northwest to southeast generally.This was agreed with the spatial distribution of the strength in gold mining activities over the studied region.The concentrations of Hg and Pb were higher than their relative backgrounds in the corps,and were even 9.48 and 25.09 times higher than their relative backgrounds in residents'hair,respectively.All these showed that the heavy metals in the soil had a high potential ecological risk,especially,had been affecting these crops'growing and yield,and even the residents'health through food strains.Obviously,these metals'potential ecological harm had been coming down to observed harm to the ecology.

Migration and speciation transformation mechanisms of mercury in undercurrent zones of the Tongguan gold mining area, Shaanxi Loess Plateau and impact on the environment

In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infiltration test and laboratory test were carried out in three typical sections of river-side loess,alluvial and proluvial strata in Tongguan gold mining area of Shaanxi Province,and the following results were obtained:(1)The source of Hg in subsurface flow zone is mainly caused by mineral processing activities;(2)the subsurface flow zone in the study area is in alkaline environment,and the residual state,iron and manganese oxidation state,strong organic state and humic acid state of mercury in loess are equally divided in dry and oxidizing environment;mercury in river alluvial or diluvial strata is mainly concentrated in silt,tailings and clayey silt soil layer,and mercury has certain stability,and the form of mercury in loess is easier to transform than the other two media;(3)under the flooding condition,most of mercury is trapped in the silt layer in the undercurrent zone where the sand and silt layers alternate with each other and the river water and groundwater are disjointed,and the migration capacity of mercury is far less than that of loess layer and alluvial layer with close hydraulic connection;(4)infiltration at the flood level accelerates the migration of pollutants to the ground;(5)the soil in the undercurrent zone is overloaded and has seriously exceeded the standard.Although the groundwater monitoring results are safe this time,relevant enterprises or departments should continue to pay attention to improving the gold extraction process,especially vigorously rectify the small workshops for illegal gold extraction and the substandard discharge of the three wastes,and intensify efforts to solve the geological environmental problems of mines left over from history.At present,the occurrence form of mercury in the undercurrent zone is relatively stable,but the water and soil layers have been polluted.The risk of disjointed groundwater pollution can not be ignored while giving priority to the treatment of loess and river alluvial landform areas with close hydraulic links.The research results will provide a scientific basis for water conservancy departments to groundwater prevention and control in water-deficient areas of the Loess Plateau.

Exposure of aboriginal people to methylmercury due to gold mining in the Amazon, Brazil

This paper outlines the results of our study aiming at evaluating the actual extent of human exposure to Hg mainly in Tapajos River Basin in central Amazonia, which is considered to be the oldest and most productive gold mining area in the Amazon. Human hair and blood as well as fish samples were collected from gold mining areas and various fishing villages located at different distances from main gold mining areas, and analyzed for total mercury(T Hg) and methylmercury (MeHg) with new methods recently being developed in our laboratory. The results to date showed the inhabitants of fishing villages particularly in the upstream Tapajos areas were constantly exposed to MeHg at abnormally high levels, with little confounding exposure to inorganic Hg. A highly significant correlation between Hg in hair and blood was observed in fishing villages, and the ratios of hair Hg to blood Hg were very close to 250g, generally established for MeHg. While, the levels of MeHg in hair and blood of gold miners and goldshop workers were low, indicating that they were mainly exposed to Hg in inorganic form. From these data, together with the levels of MeHg in fish, Hg contamination mechanisms are discussed.

Epidemiological investigation on mercury contamination in gold mining and its effect on health

In this paper, it is reported the environmental contamination of mercury in gold mining in China and the effect of mercury exposure on health. The results showed that Hg concentration of air in the Hg\|use workshop, the mining area and the population's living area were 0.058 mg/m 3, 0.047 mg/m 3 and 0.043 mg/m 3, respectively. Hg content of air in the suburbs 5 km from the mining area was 0.007 mg/m 3. The difference in Hg concentration of air was statistically significant ( p <0.05) between the Hg\|use workshop and the population's living area. But there was no difference between the mining area and the population's living area ( p >0.05). All of the values determined above were excessed the Chinese national standards. Hg concentration of snowfall and soil in the mining area were 0.058 mg/L and 2.78 μg/g. Both of them differed from those of the living area ( p< 0.01 and p <0.05). Hg content of the waste water was up to the national emission standards. Hg contents of wild plants differed inside as compared to outside the mining area ( p <0.05). But Hg content of plants of the two places was both in the range of the background. The results that Hg levels accumulated in the bodies showed that Hg concentration of hair, blood and urine of the workers of the Hg\|exposed group (group I, GI) were all higher than those of the non\|Hg\|exposed group (group II, GII). Hg in hair and urine was statistically significant ( p<0.001 and p<0.005) between the two groups. Hg content of hair of twenty\|five percent of workers in GI was higher than 4 ppm, and a small number of workers in this group was higher than 10 ppm. The Hg content of urine of eighty percent of workers in GI was higher than that of the Chinese normal human's standard. Some slight but typical clinical symptoms, of Hg poisoning were found in some worker's by clinical examination. It proved that the environment of the gold mining area was polluted by Hg vapor in varying degrees. The population was suffering from mild degree of Hg poisoning. It pointed to the fact that protecting the ecosystem and human's health against Hg pollution should be paid great attention in this gold mining area.

Mercury consumption and contamination of environment in gold mining in China

Amalgamation (sluice methods) used in the extraction of golds from ores and concentrates causes mercury contamination of the environment, which is increasingly concerned in China. The mercury specific consumption in the technical procedures has been evaluated based on the investigation of 33 mines. The average consumption of Hg is 14.6 g/ton raw ores, the ratio of Hg to gold is 6.35 g(Hg)/g(Au), total consumption of Hg in 1995 was 80 tons. The mercury amount entering into environment was 20 tons/a. Up to now 13.26% total gold produced in China is still using amalgamation, although prohibition of amalgamation since 1985 was officially proclaimed. At present, the amalgamation usage tendds to go up in some companies becasue of the benefic promotion. The irreversible mercury consumption was dispersed in the air(50%), tailing (23%) and partly(27%) entered into the downward products in the production, such as ore concentrates which was refined in the plants and caused pollution of environment near the smelter.

Physical and Metals Impact of Traditional Gold Mining on Soils in Kombo-Laka Area (Meiganga, Cameroon)

Concentrations of metals (As, Cr, Cd, Fe, Ni, Pb, Sb, and Zn) in soil samples from Kombo-Laka were investigated. The area under study is subjected to traditional gold mining and receives various wastes from miners and mining activities. Direct observations on the field displayed the destruction of soils by this activity. An assessment of pollution was performed using an Enrichment Factor (EF) and geoaccumulation index (Igeo). Levels of As, Cr, Cd, Cu, Pb and Sb in soil samples were above average in the Upper Continental Crust (UCC). EF revealed anthropogenic sources for Cd, As and Sb in these soils. Igeo indicates that Kombo-Laka soils are moderately to extremely polluted with As and Sb. There are high to very high positive correlations among the metals suggesting their possible common sources. This study reveals that traditional gold mining activities in the area are harmful to the environment.

Gold mining in Siberia and the Far East as a source of mercury contamination of the environment

The results of scientific and applied investigations on mercury contamination in the areas impacted by gold mining in Siberia and the Far East were considered. Gold mining has an impact on the contamination not only in industrial but in residential territories too. The mutual Russian Chinese investigation on mercury contamination of the Amur (Heilongjiang) River was proposed. The program of solving of the problems of mercury contamination in Russian gold mining areas is discussed.

Spatial distribution and potential ecological and health risks associated with heavy metals in the Ijero-Ekiti mining site,Nigeria

Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-term effects on economy,environment,and society.This study collected soil samples from 16 sample points including a control point to examine the pollution degrees and spatial distribution of heavy metals,as well as ecological and health risks associated with heavy metal pollution in the Ijero-Ekiti mining site,Nigeria.Geographical Information System(GIS)and remote sensing technologies were used to identify regions with high concentrations of heavy metals and assess the environmental impact of gold mining activities.The results show that the mean heavy metal concentrations of 16 soil pointa are 8.94(±5.97)mg/kg for As,0.18(±0.54)mg/kg for Cd,0.11(±1.06)mg/kg for Co,14.32(±3.43)mg/kg for Cr,6.89(±0.64)mg/kg for Cu,48.92(±11.77)mg/kg for Fe,135.81(±30.75)mg/kg for Mn,5.92(±0.96)mg/kg for Ni,5.72(±1.66)mg/kg for Pb,and 13.94(±1.38)mg/kg for Zn.The study reveals that heavy metal concentration in soils follows the order of Mn>Fe>Cr>Zn>As>Cu>Ni>Pb>Co>Cd.An analysis of soil samples indicates that 3 principal components(PCs)account for 70.008%of the total variance and there are strong positive correlations between various pairs of heavy metals.The total potential ecological risk index(309.599)in the study area is high.Non-carcinogenic risk suggests that there may be long-term health impacts on people who work in the mining areas due to chronic exposure to the environment.Based on the study,the hazard index of carcinogenic health risks associated with heavy metals through ingestion is 520.00×10^(–4).Dermal contact from As and Cr also increases the risk of cancer,with the highest hazard index value of 18.40×10^(–4).The lowest exposure pathway,with the hazard index value of 0.68×10^(–4),indicates that the inhalation of heavy metals has a comparatively low risk of cancer.This study recommends the formulation of policies to monitor the Ijero-Ekiti mining site and other regions in Nigeria where indiscriminate artisanal gold mining activities exist.

The Ban on Illegal Mining in Ghana: Environmental and Socio-Economic Effect on Local Communities

The study was conducted to assess the effects of small-scale (artisanal) gold mining and its social and economic implications on the people in Amansie West District of Ghana. The artisanal gold mining communities were studied using secondary data from scholarly articles and journals, books, conference papers, research reports, policy documents, working papers, and briefs. Descriptive and systematic analyses were conducted. The result indicated that youth aged between 21 - 30 were most likely to engage in illegal mining operations in the selected study areas. The study revealed that farmland had been destroyed, making farming difficult for the inhabitants. It is evident from the review that dug-out pits from mining serve as breeding grounds for mosquitoes and death traps for humans. The study, therefore, accentuates the need for illegal small-scale gold mining to be formalised and strategic interventions and policies proposed for the protection of Ghana’s Natural resources. Furthermore, community members should be involved in policy-making and environmental protection issues to help control the menace of landscape destruction. Although the ban on illegal gold mining activity by the government has caused more people to lose their jobs leading to livelihood challenges in mining communities, it is a step in the right direction, as the ban seeks to halt and check the illegal small-scale mining sector. The study recommended alternative livelihood and income-generating projects such as beekeeping, mushroom culture, grasscutter rearing, and agroforestry technologies including the growth of economic fruit trees as alternative livelihood ventures.

Gold Mining Enterprises Are Mulling Over Overseas M&A

China’s gold mining enterprises are actively plotting deployment of overseas resources,the'Thirteenth Five Year Plan'period may become a crucial period for resource reserve expansion by domestic gold enterprises.'China National Gold Group Corporation will quicken its pace of walking out,and speed up the process of setting up a batch of

Survival of Seedlings of Native Woody Species in the Rehabilitation of Gold Mined-Site within a Three Years Old Acacia mangium Willd Plantation of St. Elizabeth-Mahdia, Guyana

Active restoration is a critical component of biodiversity conservation for degraded tropical forest ecosystems caused by artisanal gold mining, and the success of restoration is dependent on native species selection. However, significant knowledge gaps exist regarding when and where to plant trees. This article reports on a revegetation trial undertaken in St Elizabeth, Mahdia, Guyana, to assess the survival and RGR (Relative Growth Rate) of three native woody trees and shrubs planted within three years old Acacia mangium Willd trees pruned and unpruned blocks. ANOVA (Analysis of Variance) for a completely randomized block design with four blocks, two pruned and two unpruned, within A. mangium plots. Biochar treatment was added to the plants during transplanting. Thirty-six (36) wildlings of Humiria balsamifera (Aublet.) (Tauroniro), Goupia glabra Aublet (Kabukalli), and Vismia guianensis (Aublet.) Choisy (Bloodwood) were collected and raised in a tree nursery for two weeks. The native plants were transplanted 3 m apart, survival observations and each seedling’s initial height and diameter were measured and recorded. After the experiment, 13% of seedlings from a population of 720 had died, with the highest mortality being experienced at the 92 days of the experiment (t ≤ 122 days). While the overall survival rates were high, emphasizing the importance of field trials on native and exotic species in different environments is essential to fill the knowledge gaps on suitable species for restoration in degraded areas with other land use histories.

Mining the Green Gold

Ethiopian and Chinese bamboo craftsmen work to develop the untapped potential of Africa＇s largest bamboo forests.

Visceral Leishmaniasis at the National Reference University Hospital Center of N’Djamena (Chad): Epidemiological, Clinical, Diagnostic, Therapeutic and Prognostic Aspects

Introduction: leishmaniasis is a group of parasitic diseases caused by a parasite of the genus Leishmania transmitted by the bite of an infected vector called a sandfly. There are four forms. Visceral leishmaniasis is the most severe form. The aim of our work is to study the epidemiological, clinical, diagnostic, therapeutic and prognostic aspects of the disease in the Infectious Diseases Department of the Centre Hospitalier Universitaire de Référence Nationale in N'Djaména. Methodology: Patients were recruited on the basis of clinical signs suggestive of visceral leishmaniasis, i.e. prolonged fever, splenomegaly and altered general condition. Biological confirmation was performed with a rapid diagnostic test using recombinant K39 parasite antigen, which is known to have good specificity and sensitivity. Epidata version 3.1 software was used to process patient data. Results: From 05/04/21 to 15/12/23, 153 positive cases were managed. The mean age of patients was 18 years, with a sex ratio of 9.2. Of these patients, 103 (67.3%) had recently stayed at gold mining sites. Patients testing positive were treated with sodium stibogluconate combined with paromomycin for 17 days. The mortality rate was 13.2%. Conclusion: Leishmaniasis is a serious and little-known disease in Chad. In order to respond to the disease, it is necessary to reinforce the capacities of health structures and to carry out appropriate actions in the outbreaks.

Mining Threats to Ancient Anthropogenic Soils and other Resources Associated to Indigenous Food Security in the Middle Caqueta River, Colombia

Mining is encroaching upon Protected Areas and Indigenous Reserves in the Colombian Amazon. In the Middle Caqueta region small-scale, illegal gold mining is eroding riverbanks, affecting water quality, and jeopardizing the livelihoods of indigenous peoples. In addition, mining also threatens the integrity of pre-Columbian anthropogenic soils （terra preta） created between 500 years to 2,000 years B.P. on the bluffs of the Caqueta . River. These soils are the only, non-flooded fertile soils present in the region, and as such are important for local indigenous communities. In Colombia, there is little knowledge about Terra Preta soils. This work assesses the present and potential dangers artisanal mining has for terra preta soils and other natural resources that are central to indigenous peoples＇ food security. Results posit that more knowledge is needed about the way terra preta soils are related to the livelihoods of indigenous people so that informed policy decisions can be made about the desirability of mining in the region.

Occupational Health Hazards among Large-Scale Gold Mineworkers in Ghana

Introduction: The mining industry ranks among the most hazardous occupations globally owing to the high prevalence of workplace accidents. To better protect workers in the industry, there is a need for a comprehensive understanding of risk factors, common illnesses and provision of PPE. Objective: This study examined the prevalence and underlying risk factors to work-related injuries, common illnesses, and Personal Protective Equipment (PPE) usage among mineworkers in two large-scale mining companies in Ghana that consented to participation. Methodology: Two hundred mineworkers were selected through stratified sampling in these companies using a semi-structured questionnaire. Chi-square test and binomial logistic regression were employed to determine the relationship between the incidence of occupational injury and selected risk factors using R studio. Results: The results showed that more than a tenth (16%;n = 31) of mineworkers had sustained physical injuries since being employed—mostly lacerations (53%). Out of those injured, (85%;n = 22) reportedly sustain an injury annually. A little more than half (57%;n = 112) of the mineworkers work for more than 40 hours per week. Injuries were significantly associated with the type of profession at the mine (p = 0.04;χ2 = 4.3)—Technicians and Mechanics were more likely to be injured. Although not statistically significant, working for more than 40 hours/week doubled the odds of being injured at the workplace (aOR = 1.77;95% CI: -0.27 - 1.48). The topmost illnesses among mineworkers were musculoskeletal pains (MSPs) [53%] and headaches (35%). About two-thirds (65%) had all the needed PPEs for their work. Safety goggles were the predominant PPE reportedly lacking among the mineworkers (16%;n = 31). Conclusion: There is a need for targeted training/intervention programmes and adoption of assistive ergonomic devices to protect mineworkers.

Province-scale commonalities of some world-class gold deposits:Implications for mineral exploration

Discovery rates for all metals, including gold, are declining, the cost per significant discovery is increasing sharply, and the economic situation of the industry is one of low base rate. The current hierarchical structure of the exploration and mining industry makes this situation difficult to redress. Economic geologists can do little to influence the required changes to the overall structure and philosophy of an industry driven by business rather than geological principles, However, it should be possible to follow the lead of the oil industry and improve the success rate of greenfield exploration, necessary for the next group of lower-exploration-spend significant mineral deposit discoveries. Here we promote the concept that mineral explorers need to carefully consider the scale at which their exploration targets are viewed. It is necessary to carefully assess the potential of drill targets in terms of terrane to province to district scale, rather than deposit scale, where most current economic geology research and conceptual thinking is concentrated. If orogenic, IRGD, Carlin-style and IOCG gold-rich systems are viewed at the deposit scale, they appear quite different in terms of conventionally adop- ted research parameters. However, recent models for these deposit styles show increasingly similar source-region parameters when viewed at the lithosphere scale, suggesting common tectonic settings. It is only by assessing individual targets in their tectonic context that they can be more reliably ranked in terms of potential to provide a significant drill discovery. Targets adjacent to craton margins, other lithosphere boundaries, and suture zones are clearly favoured for all of these gold deposit styles, and such exploration could lead to incidental discovery of major deposits of other metals sited along the same tectonic boundaries.