Assessment of Gold and Mercury Losses in an Artisanal Gold Mining Site in Nigeria and Its Implication on the Local Economy and the Environment
Abstract
:1. Introduction
2. Overview of ASGM in Uke Artisanal Gold Mining/Processing Site
3. Materials and Methods
3.1. Procedure for Gold Balance
- Five gold concentration processing operations in use (sluice boxes) were identified and sampled.
- Sampling in each sluice box was performed by collecting, every 15 min. with a mug, a sample of approximately 250 mL of pulp of feeding material (a cup of pulp) entering the sluice box. The sample was tossed into a 20 kg bucket (designated for Feed samples). After 15 min, another feed sample was collected in the same operation and added to the same bucket. Concomitantly, samples of 250 mL of pulp with 20% solids leaving the process (tailings) were collected and added into another bucket: the Tailing bucket. Samples of Feed and Tailings were collected for 4 h in each operation and added into the respective buckets (Figure 8).
- The solid materials collected were allowed to settle in the buckets and water was syphoned off. The two composite samples per operation, Feeds and Tailings, were separately dried under the sun.
- Two dry samples per operation, of approximately 1.5–2 kg/sample, were sent to a chemical lab.
- Fire assay of 50 g of sample: A gold bead was dissolved with aqua regia, and the gold grade was read in an Atomic Absorption Spectrometer at SGS Lab in Accra, Ghana.
- An intensive cyanidation of 500 g of a sample ground below 0.074 mm and 1 L of water with 10 g of Leachwell©, which is 75% NaCN; 25% Sodium M-Nitrobenzene Sulphonic Acid, a strong oxidant; and ~0.5% Lead Nitrate, to speed up the cyanidation process. The leaching was conducted in rolling bottles for 2 h and solubilized gold was analyzed by Atomic Absorption Spectrometry.
3.2. Methodology for Mercury Balance
- The weight of mercury before the miners adding it to amalgamate the concentrates was determined in a scale (this is the Mercury Entering).
- The weight of the recovered mercury after the miners squeezed the amalgam off in a piece of fabric was determined (this is the Mercury Recovered by Filtering).
- The weight of the amalgam the miners obtained after squeezing out the excess mercury was determined.
- The weight of the gold doré after the amalgam was burned was measured (the difference between this weight and the previous weight is the Mercury Lost by Evaporation). This is the mercury with high potential to cause health problems.
- The difference among Mercury Entering-Mercury Recovered-Mercury Evaporated = Mercury Lost with Tailings was the mercury with high potential to create environmental problems, such as that to be oxidized, complexed, methylated, and incorporated into the aquatic biota. This is also the mercury that forms toxic forms of complexes in the cyanidation plants.
4. Results and Discussion
4.1. Gold Results
4.2. Mercury Loss Results
4.3. Gold and Mercury in an Amalgamation Tailing
5. Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
- Oramah, I.T.; Richards, J.P.; Summers, R.; Garvin, T.D.; McGee, T.K. Artisanal and Small-Scale Mining in Nigeria: Experiences from Niger, Nasarawa and Plateau States. Extr. Ind. Soc. 2015, 2, 694–703. [Google Scholar] [CrossRef]
- Otoijamun, I.; Kigozi, M.; Abdulraman, S.O.; Adetunji, A.R.; Onwualu, A.P. Fostering the Sustainability of Artisanal and Small-Scale Mining (ASM) of Barite in Nasarawa State, Nigeria. Sustainability 2021, 13, 5917. [Google Scholar] [CrossRef]
- MMSD—Ministry of Mines and Steel Development (former MSMD). Nigeria’s Mining and Metals Sector: Investment Promotion Brochure; Deloitte: Abuja, Nigeria, 2016; 31p. Available online: https://msmd.gov.ng/wp-content/uploads/2022/09/Nigeria-Ministry-of-Solid-Minerals-Investment-BrochureV11.pdf (accessed on 16 September 2024).
- MMSD. Nationwide Baseline Study on the Development of Artisanal and Small-Scale Mining in Nigeria: Final Report; Wardell Armstrong: Stoke-on-Trent, UK, 2008; 255p. Available online: https://www.delvedatabase.org/uploads/resources/Nationwide-Baseline-Study-on-the-Development-of-Artisanal-Small-Scale-Mining-in-Nigeria_1-2.pdf (accessed on 16 September 2024).
- Plumlee, G.S.; Durant, J.T.; Morman, S.A.; Neri, A.; Wolf, R.E.; Dooyema, C.A.; Hageman, P.L.; Lowers, H.A.; Fernette, G.L.; Meeker, G.P.; et al. Linking Geological and Health Sciences to Assess Childhood Lead Poisoning from Artisanal Gold Mining in Nigeria. Environ. Health Perspect. 2013, 121, 744–750. [Google Scholar] [CrossRef] [PubMed]
- Umar-Tsafe, N.T.; Olayinka, A.T.; Ahmed, S.; Shehu, M.S.; Poggensi, G.; Habib, A.G.; Sabitu, K.; Nguku, P.M.; Jafiya, A.; Kachalla, M.G.; et al. The Lead Poisoning Control in Zamfara and Niger States, Nigeria: A 2010–2018 Review. In Proceedings of the International Conference of Drug Discovery & Translational Medicine 2018, Putrajaya, Malaysia, 3 December–5 February 2019. [Google Scholar] [CrossRef]
- Dooyema, C.A.; Neri, A.; Lo, Y.-C.; Durant, J.; Dargan, P.I.; Swarthout, T.; Biya, O.; Gidado, S.O.; Haladu, S.; Sani-Gwarzo, N.; et al. Outbreak of Fatal Childhood Lead Poisoning Related to Artisanal Gold Mining in Northwestern Nigeria, 2010. Environ. Health Perspect. 2012, 120, 601–607. [Google Scholar] [CrossRef]
- Environmental Law Institute. Artisanal and Small-Scale Gold Mining in Nigeria: Recommendations to Address Mercury and Lead Exposure; Environmental Law Institute: Washington, DC, USA, 2014; 75p, Available online: https://www.eli.org/research-report/artisanal-and-small-scale-gold-mining-nigeria-recommendations-address-mercury-and (accessed on 16 September 2024).
- Nigeria Federal Ministry of Environment. National Action Plan for the Reduction and Eventual Elimination of Mercury Use in Artisanal and Small-Scale Gold Mining in Nigeria; The Federal Ministry of Environment: Abuja, Nigeria, 2021; 174p. Available online: https://minamataconvention.org/sites/default/files/documents/national_action_plan/Nigeria_ASGM_NAP_2021_EN.pdf (accessed on 16 September 2024).
- Yoshimura, A.; Suemasu, K.; Veiga, M.M. Estimation of Mercury Losses and Gold Production by Artisanal and Small-Scale Gold Mining (ASGM). J. Sustain. Metall. 2021, 7, 1045–1059. [Google Scholar] [CrossRef]
- USGS—United States Geological Survey. 2019 Minerals Yearbook: Nigeria; USGS: Reston, VA, USA, 2020. Available online: https://pubs.usgs.gov/myb/vol3/2019/myb3-2019-nigeria.pdf (accessed on 16 September 2024).
- Intergovernmental Forum on Mining, Minerals, Metals and Sustainable Development (IGF). Global Trends in Artisanal and Small-Scale Mining (ASM): A Review of Key Numbers and Issues; International Institute for Sustainable Development: Winnipeg, MB, Canada, 2017; 81p, Available online: https://www.iisd.org/publications/report/global-trends-artisanal-and-small-scale-mining-asm-review-key-numbers-and (accessed on 16 September 2024).
- Adesipo, A.A.; Akinbiola, S.; Awotoye, O.O.; Salami, A.T.; Freese, D. Impact of Mining on the Floristic Association of Gold Mined Sites in Southwest Nigeria. BMC Ecol. 2020, 20, 9. [Google Scholar] [CrossRef]
- Adebayo, O.E.; Abosede, T.; Temitope, O.O.; Olusegun, O.A. Effects of Artisanal Gold Mining Activities on Soil Properties in a Part of Southwestern Nigeria. Cogent Environ. Sci. 2017, 3, 1305650. [Google Scholar] [CrossRef]
- Salami, M.A.; Jimoh, A.; Muoghalu, J.I. Impact of Gold Mining on Vegetation and Soil in Southwestern Nigeria. Int. J. Environ. Stud. 2003, 60, 343–352. [Google Scholar] [CrossRef]
- Ako, T.A.; Onoduku, U.S.; Oke, S.A.; Adamu, I.A.; Mamodu, A.; Ibrahim, A.T. Environmental Impact of Artisanal Gold Mining in Luku, Minna, Niger State, North Central Nigeria. J. Geosci. Geomat. 2014, 2, 28–37. Available online: https://pubs.sciepub.com/jgg/2/1/5/ (accessed on 16 September 2024).
- Odukoya, A.M.; Olobaniyi, S.B.; Oluseyi, T.O. Assessment of Potentially Toxic Elements Pollution and Human Health Risk in Soil of Ilesha Gold Mining Site, Southwest Nigeria. J. Geol. Soc. India 2018, 91, 743–748. [Google Scholar] [CrossRef]
- Minamata Convention on Mercury Nigeria—Notification—Article 30.4. 1 February 2018. Available online: https://minamataconvention.org/en/search?text=Nigeria (accessed on 12 September 2024).
- Global Environmental Facility GEF GOLD+ in Nigeria: Enhancing the Formalization and Mercury-Free Gold in Nigeria. 2013. Available online: https://www.thegef.org/projects-operations/projects/10603 (accessed on 16 September 2024).
- Veiga, M.M.; Fadina, O. A Review of the Failed Attempts to Curb Mercury Use at Artisanal Gold Mines and a Proposed Solution. Extr. Ind. Soc. 2020, 7, 1135–1146. [Google Scholar] [CrossRef]
- Veiga, M.M.; Angeloci-Santos, G.; Meech, J.A. Review of Barriers to Reduce Mercury Use in Artisanal Gold Mining. Extr. Ind. Soc. 2014, 1, 351–361. [Google Scholar] [CrossRef]
- Holley, E.A.; Smith, N.M.; Delgado-Jimenez, J.A.; Casasbuenas-Cabezas, I.; Restrepo-Baena, O.J. Socio-Technical Context of the Interactions between Large-Scale and Small-Scale Mining in Marmato, Colombia. Resour. Policy 2020, 67, 101696. [Google Scholar] [CrossRef]
- Zolnikov, T.R. Limitations in Small Artisanal Gold Mining Addressed by Educational Components Paired with Alternative Mining Methods. Sci. Total Environ. 2012, 419, 1–6. [Google Scholar] [CrossRef]
- Jønsson, J.B.; Appel, P.W.U.; Chibunda, R.T. A Matter of Approach: The Retort’s Potential to Reduce Mercury Consumption within Small-Scale Gold Mining Settlements in Tanzania. J. Clean. Prod. 2009, 17, 77–86. [Google Scholar] [CrossRef]
- Stocklin-Weinberg, R.; Veiga, M.M.; Marshall, B.G. Training Artisanal Miners: A Proposed Framework with Performance Evaluation Indicators. Sci. Total Environ. 2019, 660, 1533–1541. [Google Scholar] [CrossRef]
- Velásquez-López, P.C.; Veiga, M.M.; Hall, K. Mercury Balance in Amalgamation in Artisanal and Small-Scale Gold Mining: Identifying Strategies for Reducing Environmental Pollution in Portovelo-Zaruma, Ecuador. J. Clean. Prod. 2010, 18, 226–232. [Google Scholar] [CrossRef]
- Balzino, M.; Seccatore, J.; Marin, T.; Tomi, G.D.; Veiga, M.M. Gold Losses and Mercury Recovery in Artisanal Gold Mining on the Madeira River, Brazil. J. Clean. Prod. 2015, 102, 370–377. [Google Scholar] [CrossRef]
- Nigerian Geological Survey Agency. New Gold Finds in Nigeria; Nigerian Geological Survey Agency: Abuja, Nigeria, 2020; 5p. Available online: https://ngsa.gov.ng/wp-content/uploads/2020/06/Gold.pdf (accessed on 16 September 2024).
- Google Location of Abuja and Uke. 2024. Available online: https://www.google.ca/maps/search/Abuja+Nigeria+Uke+region/@8.8065373,7.0960505,9.11z?entry=ttu&g_ep=EgoyMDI0MDkwNC4wIKXMDSoASAFQAw%3D%3D (accessed on 11 September 2024).
- Odukoya, A.M.; Uruowhe, B.; Watts, M.J.; Hamilton, E.M.; Marriott, A.L.; Alo, B.; Anene, N.C. Assessment of Bioaccessibility and Health Risk of Mercury within Soil of Artisanal Gold Mine Sites, Niger, North-Central Part of Nigeria. Environ. Geochem. Health 2022, 44, 893–909. [Google Scholar] [CrossRef]
- Hinton, J.J.; Veiga, M.M.; Beinhoff, C. Women, Mercury and Artisanal Gold Mining: Risk Communication and Mitigation. J. Phys. IV France. 2003, 107, 617–620. [Google Scholar] [CrossRef]
- Park, J.-D.; Zheng, W. Human Exposure and Health Effects of Inorganic and Elemental Mercury. J. Prev. Med. Public Health 2012, 45, 344–352. [Google Scholar] [CrossRef]
- Mitra, S. Mercury in the Ecosystem; Trans Tech Publications Ltd.: Wollerau, Switzerland, 1986; 327p, ISBN 978-0-87849-529-0. [Google Scholar]
- Chang, L.W. Pathological Effects of Mercury Poisoning. In The Biogeochemistry of Mercury in the Environment; Nriagu, J.O., Ed.; Elsevier/North-Holland Biomedical Press: Amsterdam, The Netherlands, 1979; pp. 519–580. ISBN 0-444-80110-3. [Google Scholar]
- World Health Organization. WHO—Environmental Health Criteria: Mercury (Inorganic); World Health Organization: Geneva, Switzerland, 1991; 168p, Available online: https://iris.who.int/bitstream/handle/10665/40626/IPCS_EHC_118.pdf (accessed on 16 September 2024).
- ATSDR—Agency for Toxic Substances and Disease Registry. Evaluating Mercury Exposure: Information for Health Care Providers. 2018; 2p. Available online: https://www.atsdr.cdc.gov/dontmesswithmercury/pdfs/info-for-health-care-providers.pdf (accessed on 17 October 2024).
- Nuttall, K.L. Interpreting Mercury in Blood and Urine of Individual Patients. Ann. Clin. Lab. Sci. 2004, 34, 235–250. [Google Scholar] [PubMed]
- Bose-O’Reilly, S.; Bernaudat, L.; Siebert, U.; Roider, G.; Nowak, D.; Drasch, G. Signs and Symptoms of Mercury-Exposed Gold Miners. Int. J. Occup. Med. Environ. Health 2017, 30, 249–269. [Google Scholar] [CrossRef] [PubMed]
- Taux, K.; Kraus, T.; Kaifie, A. Mercury Exposure and Its Health Effects in Workers in the Artisanal and Small-Scale Gold Mining (ASGM) Sector—A Systematic Review. Int. J. Environ. Res. Public Health 2022, 19, 2081. [Google Scholar] [CrossRef]
- Veiga, M.M.; Baker, R. Protocols for Environmental and Health Assessment of Mercury Released by Artisanal and Small-Scale Gold Miners. GEF/UNDP/UNIDO Global Mercury Project; UNIDO: Vienna, Austria, 2004; 155p, Available online: https://digitallibrary.un.org/record/574459?ln=en&v=pdf (accessed on 17 October 2024)ISBN 92-1-106429-5.
- BC Centre for Disease Control. BC Clinician’s Guide to Mercury; 9p. Available online: http://www.bccdc.ca/resource-gallery/Documents/Guidelines%20and%20Forms/Guidelines%20and%20Manuals/Health-Environment/Clinicians%20Guide%20for%20Mercury.pdf#page=1&zoom=auto,606,-753 (accessed on 17 October 2024).
- Abdullahi, A.S.; Mukhtar, J.I. Armed Banditry as a Security Challenge in Northwestern Nigeria. Afr. J. Sociol. Psychol. Stud. 2022, 2, 45–62. [Google Scholar] [CrossRef]
- West African Network for Peacebuilding. Addressing Armed Banditry in the North-West Region of Nigeria: Exploring the Potentials of a Multi-Dimensional Conflict Management Approach; Accra-Ghana, 2020, 12p. Available online: https://wanep.org/wanep/policy-brief-addressing-armed-banditry-in-the-north-west-region-of-nigeria-exploring-the-potentials-of-a-multi-dimensional-conflict-management-approach-2/ (accessed on 21 October 2024).
- Mezie-Okoye, C.C. Artisanal Gold Mining and Violent Conflict in Nasarawa State, Nigeria. Int. J. Innov. Stud. Sci. Eng. Technol. 2020, 6, 55–63. [Google Scholar]
- Ahmed, Y.; Oruonye, E.D. Socioeconomic Impact of Artisanal and Small Scale Mining on the Mambilla Plateau of Taraba State, Nigeria. World J. Soc. Sci. Res. 2016, 3, 2375–9747. [Google Scholar] [CrossRef]
- Idris-Nda, A.; Waziri, N.M.; Bida, A.D.; Abdullahi, S. Socio-Economic Impacts of Artisanal and Small-Scale Mining in Parts of Niger State, Central Nigeria. Int. J. Min. Sci. 2018, 4, 21–30. Available online: https://www.delvedatabase.org/uploads/resources/Idra-Nda_2018_Socioeconomic-analysis-ASM-Nigeria.pdf (accessed on 16 September 2024).
- Veiga, M.M.; Gunson, A.J. Gravity Concentration in Artisanal Gold Mining. Minerals 2020, 10, 1026. [Google Scholar] [CrossRef]
- Clarke, J.A. Simplified Gravity-Recoverable-Gold Test. Master’s Thesis, McGill University, Montreal, QC, Canada, 2005; 141p. Available online: https://escholarship.mcgill.ca/concern/theses/rn301170f (accessed on 21 October 2024).
- Crespo-Lopez, M.E.; Augusto-Oliveira, M.; Lopes-Araújo, A.; Santos-Sacramento, L.; Souza-Monteiro, J.R.; Rocha, F.F.; Arrifano, G. Mercury Neurotoxicity in Gold Miners. In Occupational Neurotoxicology; Lucchini, R.G., Aschner, M., Costa, L.G., Eds.; Advances in Neurotoxicology; Academic Press: Cambridge, MA, USA, 2022; Volume 7, Chapter 8; pp. 283–314. [Google Scholar]
- Jønsson, J.B.; Charles, E.; Kalvig, P. Toxic Mercury versus Appropriate Technology: Artisanal Gold Miners’ Retort Aversion. Resour. Policy 2013, 38, 60–67. [Google Scholar] [CrossRef]
- UNEP—UN Environmental Programme. Retort Guide: Using Retorts to Reduce Mercury Use, Emissions, and Exposures in Artisanal and Small-Scale Gold Mining: A Practical Guide. 2015. 21p. Available online: https://www.unido.org/sites/default/files/files/2017-11/Retort_guide_English.pdf (accessed on 11 September 2024).
- UNEP. Reducing Mercury Use Through Mercury Retorts in Small-Scale Gold Mining. 2010. 9p. Available online: https://www.unep.org/resources/report/reducing-mercury-use-throught-mercury-retorts-small-scale-mining-goldmining (accessed on 11 September 2024).
- Chen, A.; Danfakha, F.; Hausermann, H.; Gerson, J.R. Education and Equipment Distribution Lead to Increased Mercury Knowledge and Retort Use in Artisanal and Small-Scale Gold Mining Communities in Senegal. Clean. Prod. Lett. 2023, 5, 100050. [Google Scholar] [CrossRef]
- Kiefer, A.M.; Drace, K.; Seney, C.S.; Veiga, M.M. Challenges Associated with Using Retorts to Limit Mercury Exposure in Artisanal and Small-Scale Gold Mining: Case Studies from Mozambique, Ecuador, and Guyana. In Trace Materials in Air, Soil, and Water; Evans, K.R., Roberts-Kirchhoff, E.S., Benvenuto, M.A., Lanigan, K.C., Rihana-Abdalla, A., Eds.; v. 1210. American Chemical Society Symposium Series; Oxford University Press: Oxford, UK, 2015; Chapter 3; pp. 51–77. 240p, ISBN 13: 9780841231108. [Google Scholar] [CrossRef]
- Mitchell, C.J.; Evans, E.J.; Styles, M.T. A Review of Gold-Particle-Size and Recovery Methods; BGS Technical Report WC/97/14; British Geological Survey: Nottingham, UK, 1997; pp. 57–77. Available online: https://core.ac.uk/download/pdf/58474.pdf (accessed on 16 September 2024).
- de Andrade Lima, L.R.P.; Bernardez, L.A.; Barbosa, L.A.D. Characterization and Treatment of Artisanal Gold Mine Tailings. J. Hazard. Mater. 2008, 150, 747–753. [Google Scholar] [CrossRef] [PubMed]
- Esdaile, L.J.; Chalker, J.M. The Mercury Problem in Artisanal and Small-Scale Gold Mining. Chem.—Eur. J. 2018, 24, 6905–6916. [Google Scholar] [CrossRef] [PubMed]
- Pantoja, F.; Alvarez, R. Decrease of Pollution by Mercury in Gold Mining in Latin Amercia. In Mine Closure in Iberoamerica; Boas, V.R.C., Berreto, M.L., Eds.; CYTED/IMAAC/UNIDO: Rio de Janeiro, Brazil, 2000; pp. 178–190. ISBN 85-7227-132-5. [Google Scholar]
- UN COMTRADE Database. UN Dept of Economic and Social Affairs Mercury HS 280540. 2024. Available online: https://comtradeplus.un.org/ (accessed on 12 September 2024).
- Jones, H.R. Mercury Pollution Control; Noyes Data Co.: New Jersey, NJ, USA, 1971; 251p, ISBN 0815503660. [Google Scholar]
- Eto, K.; Takizawa, Y.; Akagi, H.; Haraguchi, K.; Asano, S.; Takahata, N.; Tokunaga, H. Differential Diagnosis between Organic and Inorganic Mercury Poisoning in Human Cases-The Pathologic Point of View. Toxicol. Pathol. 1999, 27, 664–671. [Google Scholar] [CrossRef]
- USEPA Health Effects of Exposures to Mercury. 2024. Available online: https://www.epa.gov/mercury/health-effects-exposures-mercury (accessed on 11 September 2024).
- Stopford, W. Industrial Exposure to Mercury. In The Biogeochemistry of Mercury in the Environment; Nriagu, J.O., Ed.; Elsevier/North-Holland Biomedical Press: Amsterdam, The Netherlands, 1999; pp. 367–397. ISBN 0-444-80110-3. [Google Scholar]
- Mercury Safety Products Ltd. Mercury Vapour Proof Mask. 2024. Available online: http://www.mercurysafety.com/mercury-vapour-proof-mask (accessed on 11 September 2024).
- Torkaman, P.; Veiga, M.M. Comparing Cyanidation with Amalgamation of a Colombian Artisanal Gold Mining Sample: Suggestion of a Simplified Zinc Precipitation Process. Extr. Ind. Soc. 2023, 13, 101208. [Google Scholar] [CrossRef]
- Veiga, M.M.; Tarra, A.J.A.; Restrepo-Baena, O.J.; Tomi, G.D. Coexistence of Artisanal Gold Mining with Companies in Latin America. Extr. Ind. Soc. 2022, 12, 101177. [Google Scholar] [CrossRef]
- Uriah, L.; Kenneth, T.; Gusikit, R.; Ayuba, M. Lead and Mercury Contamination Associated with Artisanal Gold Mining in Anka, Zamfara State, North Western Nigeria: The Continued Unabated Zamfara Lead Poisoning. J. Earth Sci. Eng. 2013, 3, 764–775. Available online: https://www.academia.edu/6971512/Lead_and_Mercury_Contamination_Associated_with_Artisanal_Gold_Mining_in_Anka_Zamfara_State_North_Western_Nigeria_The_Continued_Unabated_Zamfara_Lead_Poisoning (accessed on 16 September 2024).
- Uriah, L.; Stephen, N.C.; Kenneth, T. Environmental Health Impact of Potentially Harmful Element Discharges from Mining Operations in Nigeria. Am. J. Environ. Prot. 2014, 3, 14–18. Available online: https://sciencepublishinggroup.com/article/10.11648/j.ajep.s.2014030602.12 (accessed on 16 September 2024).
- Mulenga, M.; Ouma, K.O.; Monde, C.; Syampungani, S. Aquatic Mercury Pollution from Artisanal and Small-Scale Gold Mining in Sub-Saharan Africa: Status, Impacts, and Interventions. Water 2024, 16, 156. [Google Scholar] [CrossRef]
- Donkor, A.K.; Ghoveisi, H.; Bonzongo, J.-C.J. Use of Metallic Mercury in Artisanal Gold Mining by Amalgamation: A Review of Temporal and Spatial Trends and Environmental Pollution. Minerals 2024, 14, 555. [Google Scholar] [CrossRef]
- Cartier, L.E.; Bürge, M. Agriculture and Artisanal Gold Mining in Sierra Leone: Alternatives or Complements? J. Int. Dev. 2011, 23, 1080–1099. [Google Scholar] [CrossRef]
- Hilson, G. Small-Scale Mining and Its Socio-Economic Impact in Developing Countries. Nat. Resour. Forum 2002, 26, 3–13. [Google Scholar] [CrossRef]
- Adranyi, E.; Stringer, L.C.; Altink, H. The Impacts of Artisanal and Small-Scale Gold Mining on Rural Livelihood Trajectories: Insights from Ghana. Extr. Ind. Soc. 2023, 14, 101273. [Google Scholar] [CrossRef]
Sample # | Weight (kg) |
---|---|
1 | 121.00 |
2 | 123.80 |
3 | 147.00 |
4 | 148.00 |
5 | 135.80 |
6 | 118.20 |
7 | 116.60 |
8 | 127.60 |
9 | 137.80 |
10 | 137.60 |
11 | 137.20 |
12 | 120.60 |
13 | 107.40 |
14 | 110.80 |
AVERAGE | 127.81 |
STD | 12.90 |
Method of Analysis | Average Gold Grade (g/t) | STD | |
---|---|---|---|
Fire Assay (FA) | FEED | 3.80 | 0.76 |
TAILING | 2.67 | 0.49 | |
Intensive Cyanidation (CN) | FEED | 3.55 | 0.65 |
TAILING | 2.39 | 0.43 |
Sample Point | Hg Added (g) | Hg Recovered by Filtration (g) | Hg Lost by Evaporation (g) | Hg Lost with Tailings (g) | %Hg Lost by Evaporation | %Hg Lost with Tailings | %Hg Recovered | Amalgam Obtained (g) | Doré Obtained (g) | %Hg In Amalgam | Hg Lost to Au Produced | %Total Hg Lost |
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 8.78 | 4.83 | 0.25 | 3.70 | 2.85 | 42.14 | 55.01 | 0.47 | 0.22 | 46.81 | 17.95 | 44.99 |
2 | 152.00 | 33.00 | 44.00 | 75.00 | 28.95 | 49.34 | 21.71 | 75.00 | 31.00 | 41.33 | 3.84 | 78.29 |
3 | 33.00 | 13.00 | 5.00 | 15.00 | 15.15 | 45.45 | 39.39 | 7.00 | 2.00 | 28.57 | 10.00 | 60.61 |
4 | 25.00 | 19.00 | 1.19 | 4.81 | 4.76 | 19.24 | 76.00 | 2.00 | 0.81 | 40.50 | 7.41 | 24.00 |
4 | 7.50 | 4.99 | 0.50 | 2.01 | 6.67 | 26.80 | 66.53 | 4.10 | 3.60 | 87.80 | 0.70 | 33.47 |
5 | 2.40 | 1.26 | 1.13 | 0.01 | 47.08 | 0.42 | 52.50 | 2.03 | 0.90 | 44.33 | 1.27 | 47.50 |
6 | 9.46 | 6.47 | 0.30 | 2.69 | 3.17 | 28.44 | 68.39 | 3.10 | 2.80 | 90.32 | 1.07 | 31.61 |
1 | 8.48 | 2.96 | 0.77 | 4.75 | 9.08 | 56.01 | 34.91 | 1.60 | 0.83 | 51.88 | 6.65 | 65.09 |
3 | 9.45 | 6.32 | 0.40 | 2.73 | 4.23 | 28.89 | 66.88 | 2.20 | 1.80 | 81.82 | 1.74 | 33.12 |
8 | 6.58 | 4.45 | 1.90 | 0.23 | 28.88 | 3.50 | 67.63 | 5.60 | 3.70 | 66.07 | 0.58 | 32.37 |
9 | 3.12 | 1.25 | 1.07 | 0.80 | 34.29 | 25.64 | 40.06 | 3.09 | 2.02 | 65.37 | 0.93 | 59.94 |
10 | 7.13 | 4.87 | 1.10 | 1.16 | 15.43 | 16.27 | 68.30 | 4.90 | 3.80 | 77.55 | 0.59 | 31.70 |
11 | 11.38 | 8.18 | 1.48 | 1.72 | 13.01 | 15.11 | 71.88 | 7.08 | 5.60 | 79.10 | 0.57 | 28.12 |
12 | 2.95 | 1.73 | 0.23 | 0.99 | 7.80 | 33.56 | 58.64 | 1.03 | 0.80 | 77.67 | 1.53 | 41.36 |
13 | 8.56 | 6.42 | 1.88 | 0.26 | 21.96 | 3.04 | 75.00 | 8.08 | 6.20 | 76.73 | 0.35 | 25.00 |
14 | 5.63 | 4.47 | 0.40 | 0.76 | 7.10 | 13.50 | 79.40 | 1.80 | 1.40 | 77.78 | 0.83 | 20.60 |
16 | 4.81 | 2.31 | 0.86 | 1.64 | 17.88 | 34.10 | 48.02 | 3.66 | 2.80 | 76.50 | 0.89 | 51.98 |
AVE | 18.01 | 7.38 | 3.67 | 6.96 | 15.78 | 25.97 | 58.25 | 7.81 | 4.13 | 76.50 | 3.35 | 41.75 |
STD | 35.41 | 7.96 | 10.14 | 17.35 | 12.66 | 16.44 | 16.54 | 17.46 | 7.13 | 19.06 | 4.73 | 16.54 |
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Anene, N.C.; Dangulbi, B.M.; Veiga, M.M. Assessment of Gold and Mercury Losses in an Artisanal Gold Mining Site in Nigeria and Its Implication on the Local Economy and the Environment. Minerals 2024, 14, 1131. https://doi.org/10.3390/min14111131
Anene NC, Dangulbi BM, Veiga MM. Assessment of Gold and Mercury Losses in an Artisanal Gold Mining Site in Nigeria and Its Implication on the Local Economy and the Environment. Minerals. 2024; 14(11):1131. https://doi.org/10.3390/min14111131
Chicago/Turabian StyleAnene, Nnamdi C., Bashir M. Dangulbi, and Marcello M. Veiga. 2024. "Assessment of Gold and Mercury Losses in an Artisanal Gold Mining Site in Nigeria and Its Implication on the Local Economy and the Environment" Minerals 14, no. 11: 1131. https://doi.org/10.3390/min14111131
APA StyleAnene, N. C., Dangulbi, B. M., & Veiga, M. M. (2024). Assessment of Gold and Mercury Losses in an Artisanal Gold Mining Site in Nigeria and Its Implication on the Local Economy and the Environment. Minerals, 14(11), 1131. https://doi.org/10.3390/min14111131