Mineralogy and Geochemistry of Rocky Waste from Artisanal Mining Sites in Western Côte d'Ivoire

Soungari Jean Paul YEO^1, , Zié OUATTARA², Wilfried DIGBEU², Ismaïla OUATTARA¹, Abou Junior DIABY², Ismaël SYLLA¹ and Bamory KAMAGATE³

¹Department of Mines and Reservoirs, Geological and Mining Sciences, University of Man, Man, Côte d’Ivoire

²Department of Geology and Materials, Geological and Mining Sciences, University of Man, Man, Côte d’Ivoire

³Geosciences and Environment Laboratory, NANGUI ABROGOUA University, Abidjan, Côte d’Ivoire

Cite this paper:
Soungari Jean Paul YEO, Zié OUATTARA, Wilfried DIGBEU, Ismaïla OUATTARA, Abou Junior DIABY, Ismaël SYLLA and Bamory KAMAGATE. Mineralogy and Geochemistry of Rocky Waste from Artisanal Mining Sites in Western Côte d'Ivoire. American Journal of Mining and Metallurgy. 2025; 8(1):30-40. doi: 10.12691/ajmm-8-1-4

Abstract

Artisanal mining is spreading inexorably throughout Côte d’Ivoire, particularly in the western part of the country, with certain socio-environmental risks affecting both the gold miners and the populations living near mining sites. Gold is often associated with other metals and metalloids such as arsenic and lead, which are toxic to animals and humans. These toxic elements, released during mining activities, are dispersed into water and soil, while a significant proportion remains trapped in the huge amounts of waste produced and dumped into the environment. In western Côte d’Ivoire, which has become a zone of intense artisanal gold mining activity, the consequences of the activity are little studied. Indeed, the solid mining residues from this activity have not yet been the subject of a dedicated study. The present study is conducted based on observations, macroscopic and microscopic descriptions, and geochemical analyses. Microscopic studies using transmitted and reflected light revealed that the rocks from the mining sites are volcanosedimentary formations (schists and micaschists). The observed outcrops are metamorphic rocks, mostly metagranites, mica granulites, as well as granites and microgranites. These rocks are mainly composed of quartz, micas, feldspars, amphibole, and accessory minerals such as chlorite, epidote, and sericite. There is also a notable abundance of sulfides, including pyrite, chalcopyrite, pyrrhotite, arsenopyrite, and magnetite in the rocky waste, whose oxidation can lead to acid mine drainage. Geochemical analysis also highlights the effects of sulfide oxidation in the form of enrichment of residues in Cadmium, Cobalt, Chromium, Copper, Manganese, Nickel, and Palladium compared to the average concentrations of the Upper Continental Crust (UCC) or Clarke values. The trace metal elements identified in this study are specific to the geological and geochemical context of the studied area.

Keywords:
Metals and metalloids artisanal mining activity mining solid residues Western Côte d'Ivoire

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References:

[1]	J. Elder, “Metal biogeochemistry in surface-water systems; a review of principles and concepts,” Circular, 1988.
[2]	A. Papon, “Géologie et minéralisations du sud-ouest de la Côte-d’Ivoire: synthèse des travaux de l’opération SASCA 1962-1968.,” BRGM, Mémoire du BRGM, n° 80, 1973. Accessed: Nov. 11, 2025. [Online]. Available: https:// pascalfrancis.inist.fr/ vibad/index.php? action= getRecordDetail &idt= PASCALGE ODEBRGM732213702.
[3]	A. Lambert, “Prospects aurifères des monts Zya, Ity et Tontouo (Côte d’Ivoire)-Interprétation des résultats d’analyses multiéléments (ICP) effectuées sur les échantillons de puits et de sondages.,” Rapport BRGM N° 1646, 1994.
[4]	CNDH, “Rapport d’enquête sur la cartographie des sites d’orpaillage en côte d’ivoire,” Conseil National des Droits de l’Homme, 2022.
[5]	K. S. Gbamélé, S. Konan Kouakou, L. Kouassi Kouakou, A. Brou Loukou, F. Konan Koffi, and D. Bini Kouamé, “Evaluation de la Contamination Chimique des Eaux Souterraines par les Activités Anthropiques : Cas de la Zone d’Ity-Floleu Sous-Préfecture de ZouanHounien, Ouest de la Côte d’Ivoire,” ESJ, vol. 16, no. 6, 2020.
[6]	K. S. Konan, K. Kouassi, A. S. Yapo, and L. A. Brou, “Impacts de l’orpaillage sur la morphologie et la qualité des eaux du fleuve Cavally (Zouan-hounien, Côte d’Ivoire),” International Journal of Innovation and Applied Studies, vol. 28, no. 2, pp. 515–524, 2020.
[7]	P. J. O. Djadé, K. N. Keuméan, A. Traoré, G. Soro, and N. Soro, “Assessment of Health Risks Related to Contamination of Groundwater by Trace Metal Elements (Hg, Pb, Cd, As and Fe) in the Department of Zouan-Hounien (West Cöte D’Ivoire),” GEP, vol. 09, no. 08, pp. 189–210, 2021.
[8]	S. L. Coulıbaly, F. M. Zahui, L. C. Mangoua-Allali, A. Cherif, and L. Coulibaly, “Artisanal Mining Practice and Physical Impacts on the Environment in the Ity-Floleu Gold Region, Côte d’Ivoire,” IJECC, pp. 17–31, 2021.
[9]	O. C. N’Cho, I. Ouattara, Z. Ouattara, S. J.-P. Yeo, and B. Kamagate, “Soil and environment quality in artisanal small-scale mining areas in western Côte d’Ivoire,” World J. Adv. Res. Rev., vol. 20, no. 3, pp. 774–779, Dec. 2023.
[10]	Intergovernmental Forum on Mining, “Global Trends in Artisanal and Small-Scale Mining (ASM): A Review of Key Numbers and Issues,” International Institute for Sustainable Development, 2017.
[11]	M. A. Ondayo, M. J. Watts, C. J. Mitchell, D. C. P. King, and O. Osano, “Review: Artisanal Gold Mining in Africa—Environmental Pollution and Human Health Implications,” Expo Health, vol. 16, no. 4, pp. 1067–1095, Aug. 2024.
[12]	M. Champy and A. Dessertine, “« C’est la chaîne alimentaire, chacun prend pour lui. » Économie quotidienne de l’extraction aurifère de petite échelle dans un village de Côte d’Ivoire:” Afrique contemporaine, vol. N° 277, no. 1, pp. 79–101, 2024.
[13]	O. E. F. M. Illatou, “Impacts de l’orpaillage et de l’agriculture sur la qualité des eaux du Liptako nigérien : identification des hots spots des pollutions métalliques et organiques, transferts de connaissances entre recherche et terrain,” phdthesis, IMT - MINES ALES - IMT - Mines Alès Ecole Mines - Télécom ; Université Abdou Moumouni, 2021. Accessed: Nov. 11, 2025. [Online]. Available: https://theses.hal.science/tel-03624770.
[14]	S. Timsina et al., “Tropical surface gold mining: A review of ecological impacts and restoration strategies,” Land Degrad Dev, vol. 33, no. 18, pp. 3661–3674, Dec. 2022.
[15]	A. Malone et al., “Transitional dynamics from mercury to cyanide-based processing in artisanal and small-scale gold mining: Social, economic, geochemical, and environmental considerations,” Science of The Total Environment, vol. 898, p. 165492, Nov.2023.
[16]	L. Ramos, L. M. Hernandez, and M. J. Gonzalez, “Sequential Fractionation of Copper, Lead, Cadmium and Zinc in Soils from or near Doñana National Park,” J of Env Quality, vol. 23, no. 1, pp. 50–57, Jan. 1994.
[17]	A. J. Adewumi, T. A. Laniyan, T. Xiao, Y. Liu, and Z. Ning, “Exposure of children to heavy metals from artisanal gold mining in Nigeria: evidences from bio-monitoring of hairs and nails,” Acta Geochim, vol. 39, no. 4, pp. 451–470, Aug. 2020.
[18]	G. S. Plumlee et al., “Linking Geological and Health Sciences to Assess Childhood Lead Poisoning from Artisanal Gold Mining in Nigeria,” Environ Health Perspect, vol. 121, no. 6, pp. 744–750, June 2013.
[19]	C. B. Tabelin et al., “Solid-phase partitioning and release-retention mechanisms of copper, lead, zinc and arsenic in soils impacted by artisanal and small-scale gold mining (ASGM) activities,” Chemosphere, vol. 260, pp. 127–574, Dec. 2020.
[20]	E. Lombi, W. W. Wenzel, and D. C. Adriano, “Arsenic-contaminated soils: II. Remedial action,” in Remediation Engineering of Contaminated Soils, CRC Press, 2000, pp. 739–758. Accessed: Nov. 11, 2025. [Online]. Available: https:// www.taylorfrancis.com/ chapters/edit/10.1201/9781482289930-34/arsenic-contaminated-soils-ii-remedial-action-lombi-wenzel-adriano.
[21]	M. M. S. Aranguren, “Contamination en métaux lourds des eaux de surface et des sédiments du Val de Milluni (Andes Boliviennes) par des déchets miniers <br/> Approches géochimique, minéralogique et hydrochimique.” Thèse, Université Paul Sabatier - Toulouse III, 2008. Accessed: Nov. 11, 2025. [Online]. Available: https:// theses.hal.science/ tel-00277431.
[22]	K. Custer, “Cleaning Up Western Watersheds,” Environmental Impact Report, 2003.
[23]	W. A. Price, “Challenges posed by metal leaching and acid rock drainage at closed mines,” in Environmental Aspects of Mine Wastes, Jambor, J.L.; Blowes, D.W.; Ritchie, A.I.M., in Short Course Series, no. 31. , Vancouver: Mineralogical Association of Canada, 2003, pp. 1–10. Accessed: Nov. 11, 2025. [Online]. Available: https:// open.library.ubc.ca/ soa/cIRcle/ collections/ 59367/items/1.0042432.
[24]	D. G. Ahoulé, F. Lalanne, J. Mendret, S. Brosillon, and A. H. Maïga, “Arsenic in African Waters: A Review,” Water Air Soil Pollut, vol. 226, no. 9, p. 302, Sept. 2015.
[25]	K. B. Kouadio et al., “Environmental contamination by metals, metalloids, and cyanides in the historic and active ASGM area of Kokumbo in Côte d’Ivoire,” Environ Sci Pollut Res, vol. 32, no. 23, pp. 13699–13725, 2025.
[26]	S. Bakayoko, D. Soro, K. K. H. Kouadio, W. A. B. Konan, and P. Angui, “Characteristics of Tonkpi Mountain soils and plateaus soils in West Côte d’Ivoire.,” Herald Journal of Agriculture and Food Science Research, pp. 171–176, 2013.
[27]	C. B. Tiesse, E. N. Wandan, and H. D. N’da, “Apport De La Teledetection Pour Le Suivi SpatioTemporel De L’occupation Du Sol Dans La Region Montagneuse Du Tonkpi (Cote D’ivoire),” ESJ, vol. 13, no. 15, p. 310, May 2017.
[28]	J.-M. Avenard et al., Le milieu naturel de la Côte d’Ivoire, IRD Editions. 1971.
[29]	D. Z. Ettien, “Exploitation industrielle des gisements d’or et dynamique spatiale du terroir d’Ity dans l’Ouest de la Côte d’Ivoire. Une étude à base de la télédétection,” Revue de Géographie et de Lutte contre la désertification, pp. 1–15, 2010.
[30]	A. S. Kouadio, “Étude d’impact sur l’environnement, fondements théoriques et pratiques,” Université Abobo-Adjamé, Abidjan, Côte d’Ivoire, Rapport de séminaire sur les études d’impact sur l’environnement 4–6, 2001.
[31]	J. Camil, “Pétrographie, chronologie des ensembles archéens et formations associées de la région de Man (Côte d’Ivoire). Implications pour l’histoire géologique du craton ouest africain.,” Université de Cocody, Abidan, Côte d’Ivoire, 1984.
[32]	A.-N. Kouamelan, “Géochronologie et Géochimie des Formations Archéennes et Protérozoïques de la Dorsale de Man en Côte d’Ivoire. Implications pour la Transition Archéen-Protéozoïque,” phdthesis, Université Rennes 1, 1996. Accessed: Nov. 11, 2025. [Online]. Available: https://theses.hal.science/tel-00653760.
[33]	World Gold Council, “Gold demand trends data tables from 2010 to 2024.,” Goldhub – Research. Accessed: Sept. 11, 2025. [Online]. Available: https:// www.gold.org/ goldhub/ research/ gold-demand-trends.
[34]	SMI, “Projet de mise en valeur du gisement d’or d’Ity. Tome 1, descriptif technique,” SMI, Abidjan, Côte d’Ivoire, 1989.
[35]	R. L. Rudnick and S. Gao, “Composition of the Continental Crust,” in Treatise on Geochemistry, Elsevier, 2014, pp. 1–51.
[36]	A. N. Kouamelan, J.-J. Peucat, and C. Delor, “Reliques archéennes (3, 15 Ga) au sein du magmatisme birimien (2, 1 Ga) de Côte d’Ivoire, craton ouest-africain,” Comptes rendus de l’Académie des sciences. Série 2. Sciences de la terre et des planètes, vol. 324, no. 9, pp. 719–727, 1997.
[37]	S. C. Djro, “Evolution tectono-métamorphiques des gneiss granulitiques archéens du secteur de Biankouma,” Doct. ès Sci. Nat., Univ. Abidjan, p. 171, 1998.
[38]	M. Wilson, Ed., Igneous Petrogenesis: a global tectonic approach. Dordrecht: Springer Netherlands, 1989.
[39]	J. D. N. Winter, Principles of igneous and metamorphic petrology, 2nd ed., vol. 2. Pearson education Harlow, UK, 2014. Accessed: Nov. 11, 2025. [Online]. Available: http:// dni.dali.dartmouth.edu/ 1wiu2y7zem4f/12-eloise-jacobs-3/read-0321592573-principles-of-igneous-and-metamorphic- petrology--1.pdf.
[40]	J. P. Milési and J. L. Feybesse, “Gisement d’Ity (Côte d’Ivoire). Calage lithologique et structural,” BRGM Technical Note DMM/ DEX/ UR/93/029, 1993.
[41]	A.-S. Tabaud, P. Trap, D. Marquer, C. Durand, J.-L. Lescuyer, and R. Furic, “New insight on the magmatic and tectono-metamorphic evolution of the Paleoproterozoic gold-bearing Toulépleu-ity district (SW Ivory Coast),” in 13th SGA Biennial Meeting, Nancy, 2015. Accessed: Nov. 11, 2025. https:// www.researchgate.net/profile/Didier-Marquer/ publication/ 282334815_ New_ Insight_ on_the_ Magmatic_and_ TectonoMetamorphic_ Evolution_of_the_Paleoproterozoic_ GoldBearing_ToulepleuIty_ district_SW_ Ivory_Coast/links/ 5628f41208ae518e347c6bf0/New-Insight-on-the -Magmatic-and-Tectono-Metamorphic- Evolution-of-the- Paleoproterozoic-Gold- Bearing-Toulepleu-Ity -district-SW-Ivory-Coast.pdf.
[42]	P. L. Smedley, J. Knudsen, and D. Maiga, “Arsenic in groundwater from mineralised Proterozoic basement rocks of Burkina Faso,” Applied Geochemistry, vol. 22, no. 5, pp. 1074–1092, May 2007.
[43]	D. Béziat, M. Dubois, P. Debat, S. Nikiéma, S. Salvi, and F. Tollon, “Gold metallogeny in the Birimian craton of Burkina Faso (West Africa),” Journal of African Earth Sciences, vol. 50, no. 2–4, pp. 215–233, Feb. 2008.
[44]	M. M. Fonshiynwa et al., “Environmental impacts of artisanal and small-scale gold mining within Kambele and Pater gold mining sites, East Cameroon,” GeoJournal, vol. 89, no. 3, p. 100, 2024.
[45]	UNESCO, “La pollution naturelle à l’arsenic de l’eau potable est maintenant considérée comme une menace globale affectant près de 140 millions de personnes dans 70 pays sur tous les continents.,” UNESCO-WWAP (World Water Assessment Programme). Accessed: Sept. 11, 2025. [Online].: http:// www.unesco.org/ new/fr/natural:sciences/environment/water/wwap/facts-and-figures/all-factswwdr3/fact 41-natural-arsenic-pollution/.
[46]	V. Matera, “Etude de la mobilité et de la spéciation de l’arsenic dans les sols de sites industriels pollués: Estimation du risque induit,” PhD Thesis, Pau, 2001. Accessed: Nov. 11, 2025. [Online]. Available: https://theses.fr/2001PAUU3017.
[47]	V. Laperche, F. Bodénan, M. C. Dictor, and P. Baranger, “Guide méthodologique de l’arsenic, appliqué à la gestion des sites et sols pollués,” Rapport BRGM RP-52066-FR, 2003.