A Synoptic Review of Mineralogical and Chemical Characteristics of Clays in the Southern Part of Nigeria

Authors

  • Moses Oghenenyoreme Eyankware Department of Geology, Faculty of Sciences, Ebonyi State University, Abakaliki. P.M.B. 053, Ebonyi State, Nigeria;Geomoses Consultancy Limited Warri, Delta State, Nigeria
  • Christopher Ogwah Department of Geology, Faculty of Sciences, Ebonyi State University, Abakaliki. P.M.B. 053, Ebonyi State, Nigeria
  • Joy Chiaka Ike Department of Energy and Petroleum Studies, Novena University, Ogume Delta State, Nigeria

DOI:

https://doi.org/10.30564/re.v3i2.3057

Abstract

This paper reviews the mineralogical and chemical characteristics of clays found in southern part of Nigeria, with a view to determine its usability. The usability of clays, depends on its chemical and mineralogical charactertics, the end product of clay after it is been processed is also based on it’s charactertics. From reviewed literature, it was observed that sampled clay within the study area were analyzed using the XRD, XRF and ICPMS method. Further findings also revealed that the dominant clay minerals within the study area include montmorillonite, illite, and kaolinite. On the other hand, it was observed that non-clay minerals such as feldspar, quartz, dickite and many others were found with clay as revealed by several scholars. While chemical charactertics of clay consists mainly of Al2O3, K2O, CaO and SiO2, with other major oxides such as P2O5, MgO, Fe2O3, TiO2, MnO and Na2O. Some trace elements such Be, Ba, Sc, Sr, Zr, V and Y were reported to be present in clays deposit found in selected part of Ogun state. From reviewed articles, it was observed that mineralogical and chemical charactertics of clay make it suitable for pharmaceutical, textile, cosmetic and polymer industries, but considered to be fairly suitable for oil and gas industry.

Keywords:

Clay, Montmorillonite, Kaolinite, Illite, Oxide, Nigeria

References

[1] Nesse, W.D. (2000), Introduction to Mineralogy. New York: Oxford UP.

[2] Keller, WD (1970). Environmental aspects of clay minerals. J. Sed. Petrol. Geol., 40(3): 39-46.

[3] Nwosu, D.C., Ejikeme, P.C. N. and Ejikeme, E. M. (2013). Physico-chemical characterization of “NGWO” White clay for industrial use. International Journal of Multidisciplinary Sciences and Engineering, 4(3): 11-14.

[4] Umudi, E. Q., Emefiele, T. (2017).Quality Assessment of Kaolin Clay from Ozanagogo, Umutu and Otorho, Delta State, Nigeria. Journal of Sciences and Multidisciplinary Research, 9(1); 19-26.

[5] Ike, J.C., Ezeh, H. N., Eyankware, M. O., Haruna, A.I. (2021). Mineralogical and geochemical assessment of edda clays for possible use in the ceramics industry, Afikpo Sub-Basin, Nigeria. Journal of Geological Research. 3(2);41-52.

[6] Onyeogu T., Uzoegbu, M.U., Ideozu, R.U. (2016). Clay Minerals Assessment from Maastrichtian Syclinal Afikpo, Nigeria. Intern. J. of Scientific and Res. Pub., 6(9): 746-753.

[7] Aramide, F. O., Alaneme, K. K., Olubambi, P. A., Borode, J.O. (2014).Characterization of some clay deposits in South West Nigeria. Leonardo Electronic Journal of Practices and Technologies, 23; 46-57.

[8] Idenyi. N.E., Nwajagu C.O. (2003). Non metallic material technology. 1st ed. Olison publication, Enugu Nigeria.

[9] Okorie, E., Anietie, N. O., Udoh, F. D. (2015). A review of Nigerian bentonitic clay as drilling Mud. Nigeria Annual International Conference and Exhibition, Lagos Nigeria.

[10] Souza D. J.L., Varajão A.F.D.C., Yvon J., Scheller T., Moura C.A.V. (2007). Ages and possible provenance of the sediments of the Capim River kaolin, northern Brazil, Journal of South American Earth Sciences, 24, 25-33.

[11] Dominguez, E., Iglesias C., Dondi M. (2008). The geology and mineralogy of a range of kaolins from the Santa Cruz and Chubut Provinces, Patagonia (Argentina). Applied Clay Sciences, 40, 124-142.

[12] Lang W.B., Warren W.C., Thompson, R.M., Overstreet, E.F. (1965). Bauxite and kaolin deposits of the Irwinton District, Georgia. Geological Survey Bulletin, 1199-J, 1-26.

[13] Murray, H.H. (1999). Applied clay mineralogy today and tomorrow, Clay Minerals, 34; 39-49.

[14] Bloodworth, A.J., Morgan D.J., Briggs D.A. (1989). Laboratory processing trials on kaolin-bearing sandstones from Pugu, Tanzania, using conventional and new hydrocyclone bodies, Clay Minerals, 24; 539-548.

[15] Mineral Detraction. (2001). Mineral powder diraction fle data book. International Centre for Detraction Data, Newton Square, USA.

[16] Ekosse, G. I.E. (2005). Fourier transform infrared spectrophotometry and X-ray powder diffractometry as complementary techniques in characterising clay size fraction of kaolin. Journal of Applied Science and Environmental Management, 9 (2); 43-48.

[17] Baioumy H.M. (2014). Geochemistry and origin of the Cretaceous sedimentary kaolin deposits, Red Sea, Egypt, Chemie der Erde, 74; 195-203.

[18] Bam, S. A., Gundu, D.T., Akaaza, J.N. (2014). Liquid and plastic limit study of Makurdi and Ujagba clay deposits for foundry applications. Journal of Multidisciplinary Engineering Science and Technology,1(5);28-31.

[19] Faheem U. (2018). Montmorillonite: An Introduction to Properties and Utilization. Intechopen, http://dx.doi.org/10.5772/intechopen.77987.

[20] Grim, R. E. (1968a). Applied clay mineralogy, McGraw-Hill Book Co., New York, 596 pp.

[21] Środoń, J., Eberl, D.D. (1984). Illite. Mineral. Soc. Am. Rev. Mineral, 13, 495-544.

[22] Fanning, D. S, Keramides, V.Z., El-Desoky M. A. (1989). Micas. In: Dixon JB & Weed SB ed. Minerals in soil environments. Madison, Wisconsin, Soil Science Society of America, pp 551-634.

[23] Attah , L.E., Oden, M. I.(2010). Physciochemical properties and industrial potential of some clay deposits in Calabar Area, Southwestern Nigeria. Journal of Mining and geology, 9(1-2); 39-49.

[24] Elueze, A. A., Bakare, C. A., Bolarinwa, A. T. (2004). Mineralogical, industrial and chemical characteristics of residual clay occurrences in Iwo and Ijebu district, Southwestern Nigeria. Journal of mining & geology, 40(2); 119-126.

[25] Adeola, A. J., Dada R. G. (2017). Mineralogical and geochemical trends in lateritic weathering profiles on basement rocks in Awa-Oru Ijebu and its environ, southwestern Nigeria. Global Journal of Geological Sciences, 15, 1-11.

[26] Chukwu, G.U., Nwachukwu, U.H., Azunna, D.E. (2017). Geophysical characterization of Bende Clay Deposit for Industrial Applications. International Journal of Innovative Environmental Studies Research, 5(2):1-9.

[27] Elakhame, Z., Bello, S. A., Agunsoye, J. O., Patric . I., Otitoju, O. (2016). Characterization of Ujogba clay deposits in Edo State, Nigeria for refractory applications. Kathmandu University Journal of Science, Engineering and Technology, 12(2); 71- 82.

[28] Umudi, E. Q. (2017). Mineral Composition of edible clays from the Ozanagogo, Delta State, Nigeria. International Journal of Chemistry and Chemical Processes, 3(2); 20-24.

[29] Akinyemi, S. A., Ogunniyi, S. O., Ojo, A. O., Gitari, W. M., Momoh, A., Akinola, O.O., Talabi, A.O., Afolagboye, L. O., Olaolorun, O. A., Ayodele, O. S. (2014). Mineralogy, physiochemical characteristics and industrial potential of some residual clay deposits within Ekiti State , Southwestern Nigeria, International journal of earth sciences, 14(7); 70-88.

[30] Braide, S. P., Huff, W.D. (1986). Clay mineral variation in Tertiary sediments from the eastern flank of the Niger Delta. Clay Mineral, 21; 211- 224.

[31] Olaonipekun O., Georges-Ivo E., John O. (2020). Physico-chemical, Mineralogical, and Chemical Characterization of Cretaceous–Paleogene/Neogene Kaolins within Eastern Dahomey and Niger Delta Basins from Nigeria: Possible Industrial Applications Minerals, 10, 670. DOI: http://dx.doi.org/10.3390/min10080670.

[32] Onyekuru, S.O., Iwuoha P. O., Iwuagwu C. J., Nwozor K..K.., Opara K. D. (2018). Mineralogical and geochemical properties of clay deposits in parts of Southeastern Nigeria. International Journal of Physical Sciences, 13(14), 217-229.

[33] Nweke, O.M., Igwe, E.O., Nnabo, P.N. (2015). Comparative evaluation of clays from Abakaliki formation with commercial bentonite clays for use as drilling mud. Afr. J. Environ. Sci. Technol. 9 (6):508-518. http://dx.doi.org/10.5897/AJEST2015.1904.

[34] Olugbenga, A.G., Garba, M.U., Soboyejo, W., Chukwu, G. (2013). Beneficiation and characterization of a bentonite from Niger Delta Region of Nigeria. Int. J. Sci. Eng. Invest. 2 (14), 14-18.

[35] Raw Materials Research, Development Council (2007). Technical Brief on Mineral Raw Materials in Nigeria - Bentonite. RMRDC, Abuja.

[36] Aigbedion, I., Iyayi, S.E. (2007a). Formation evaluation of Oshioka field using geophysical well logs. Middle-East J. Sci. Res. 2, 107.

[37] Aigbedion, I., Iyayi, S.E. (2007b). Formation evaluation of Oshioka field using geophysical well logs. Middle-East J. Sci. Res. 2, 107.

[38] Omole, O., Adeleye, J.O., Falode, O., Malomo, S., Oyedeji, O.A. (2013). Investigation into the rheological and filtration properties of drilling mud formulated with clays from Northern Nigeria. J. Petrol. Gas Eng. 4 (1), 1-13.

[39] James, O.O., Mesubi, M.A., Adekola, F.A., Odebunmi, E.O., Adekeye, J. I. (2008). Beneficiation and characterization of a bentonite from North-Eastern Nigeria. J. N. C. Acad. Sci. 124 (4), 154-158.

[40] Nweke, O.M. (2015). Evaluating the suitability of clays from Abakaliki Area, Southeastern Nigeria for oil industrial application using geotechnical and rheological properties. Sci. Innov. 3 (2):22-31. http://dx.doi.org/10.11648/j.si.20150302.11.

[41] Afolabi, R. O., Orodu, O. D., Efeovbokhan, V, E. (2017). Properties and application of Nigerian bentonite clay deposits for drilling mud formulation: Recent advances and future prospects. Applied Clay Science, 143;39-49.

[42] Falode, O.A., Ehinola, O.A., Nebeife, P.C. (2008). Evaluation of local bentonitic clay as oil well drilling fluids in Nigeria. Appl. Clay Sci. 39:19–27. http://dx.doi.org/10.1016/j.clay.2007.04.011.

[43] Ahmed, A.S., Salahudeen, N., Ajinomoh, C.S., Hamza, H., Ohikere, A. (2012a). Studies on the mineral and chemical characteristics of Pindiga bentonitic clay. Petrol. Technol. Dev. J. 1, 1-8.

[44] Ahmed, A.S., Salahudeen, N., Ajinomoh, C.S., Hamza, H., Ohikere, A. (2012b). Studies on the mineral and chemical characteristics of Pindiga Bentonitic Clay. Petrol.Techn. Dev. J. 1, 1-8.

[45] Obaje, S.O. (2013). Suitability of Borno bentonites as drilling mud. Int. J. Sci. Technol. 3 (2), 151- 152.

[46] Inegbenebor, A.I., Sanya, O.O., Ogunniran, K.O., Inegbenebor, A.O., Adekola, A.O. (2014). Potentially exploitable base-metal containing bentonite clay minerals of Ibeshi-Ikorodu South-Western Nigeria for oil bleaching. Covenant J. Phys. Life Sci. 2 (2), 123-137.

[47] Emofurieta, W.O. (2001). The characteristics of the Nigerian bentonite. Geociecaias Rev. Univ. Aveiro 15, 39-47.

[48] Agwu, O.E., Okon, A.N., Udoh, F.D. (2015). A review of Nigerian bentonitic clays as drilling mud. Paper SPE-178264-MS Presented at the Nigeria Annual International Conference and Exhibition. Society of Petroleum Engineers, Lagos, pp. 1-18.

[49] Raw material Research and Development Council (2010). Non-Metallic Endowments in Nigeria. Federal Ministry of Science and Technology Abuja.

[50] Raw Material Research and Development Council. (2008). Research and Development Update of Raw Materials in Nigeria. Retrieved from https://www.rmrdc.gov.ng/.../raw-material...rawmaterials-update/60-raw-materials-research-and-development-council.html.

[51] Ajugwe, C., Oloro, J., Akpotu, D. (2012). Determination of the rheological properties of drilling mud from locally sourced clay from various geographical areas. J. Eng. Appl. Sci. 4,38-49.

[52] Oyinloye, A. O. (1991). Application of kaolinitic clays in Industrial Clay technology TERRA. A Journal of Environmental Concern, 1(1), 68-72.

[53] Bolarinwa and Adeola Ovat F. A., Bisong, M. K. A. (2017). Assessment of the industrial potentials of some Nigerian kaolinitic clay deposits. European Journal of Engineering and Technology, 5(2);48- 53.

[54] Olaremu AG (2015). Physico-chemical characterization of Akoko mined kaolin clay. J. Miner. Mater. Charact. Eng. 3:353-361.

[55] WHO. (2005). Bentonite, Kaolin, and Selected Clay Minerals (Environmental Health Criteria 231), World Health Organization, Geneva, 196 pp.

[56] Edozuino, F. O., Iloghalu, F. S., Akaeze M. C., Umeohia, N.O., Nwaeju, C. C., Anene, I. A. (2016). A Study of Casting Characterization of Some Nigerian Clay Slips for Industrial Production. International Journal of Advanced Scientific Research, (1)2; 41-45.

[57] Ochieng, O. (2016). Characterization and Classification of Minerals for Potential Application in Rugi Ward, Kenya. African Journal of environmental science and Technology, 10(11); 415-431.

[58] George, E.C. (2011). Industrial Clays Technical University of Crete, Department of Mineral Resources Engineering, 73100 Chania, Greece. Pp.041-49.

[59] Adewole, J. A., Modupe A. O. (2018). Mineralogical and geochemical appraisal of clay deposits in Papalanto and Its Environs, Southwestern, Nigeria. Earth Science Research, 7(1); 1-12.

[60] Murali, D., K., Sambath, K., Muhammed, S. H. (2018). A review of clay and it engineering significance. International Journal of Scientific and Research Publication, Volume 8(2); 2250-3153.

[61] Grim, R. E. (1968b) Clay mineralogy, 2nd edition. New York, McGraw-Hill, 596 pp.

[62] Okunlola, O. A. (2008). Compositional characteristics and functional Industrial Application of Itakpe clay occurrence, Central Nigeria. Eurp. Jour. of Sc. Research, 19(3); 453-461.

[63] Akinola, O. O., Obasi, R. A. (2014). Compositional Characteristics and Industrial Potential of The Lateritic Clay Deposit In Ara-Ijero Ekiti Areas, Southwestern Nigeria. International Journal of Scientific & Technology Research, 3(8); 305-311.

[64] Ajayi, J.O., Agagu, O. K. (1981). Mineralogy of primary clay deposits in the basement complex areas of Nigeria. J. Min. Geology, 18(1); 27-30.

[65] Salihu, S. A., Suleiman, I. Y. (2018). Comparative analysis of physical and chemical characteristics of selected clays deposits found in Kebbi State, Nigeria. International Journal of Physical Sciences, 13(10); 163-17.

[66] Ehinola, O. A., Oladunjoye, M. A., Gbadamosi T. O. (2009). Chemical composition, geophysical mapping and reserve estimation of clay deposit from parts of Southwestern Nigeria. Journal of Geology and Mining Research, 1(3); 057-066.

[67] Olaolorun, O., Oyinloye, A. O. (2010). Geology and geotechnical appraisal of some clay deposits around IjeroEkiti Southwestern Nigeria: Implication for Industrial Uses. Pak.J. Sci. Ind. Res., 53, (3) 127-135.

[68] Onyeobi, T. U. S., Imeokparia, E. G., Ilegieuno, O. A., Egbuniwe, I. G. (2013). Compositional, Geotechnical and Industrial characteristics of Some Clay Bodies in Southern Nigeria. Journal of Geography and Geology, 2(3); 73-82.

[69] Igbozuruike, M.U. (1975). Climatology and Vegetation types. Eastern states Ethiope Publishing House, Benin City.

[70] Monanu, P. C. (1975). Rainfall. In: Nigeria in maps: Eastern States, Ofomata, G.E.K. (Ed). Ethiope Publishing House, Benin City, Nigeria, pp. 25-26.

[71] Eyankware, M.O., Obasi, P. N. (2015). Physiochemical analysis of water resources in selected part of Oji-river, Enugu State southeastern Nigeria. Intern Jour of innovative and Science Research International Journal of Innovational and Scientific Research, 10(1):171-178.

[72] Okorie, P.N., Ademowo, G.O., Saka, Y., Davies, E., Okoronkwo, C., Bockarie, M. J., Molyneux, D. H., Kelly-Hope, L. A. (2013). Lymphatic Filariasis in Nigeria; Micro-stratification Overlap Mapping (MOM) as a Prerequisite for Cost Effective Resource Utilization in Control and Surveillance. PLoS Negl Trop Dis 7(9): e2416. DOI: https://doi.org/10.1371/journal.pntd.0002416.

[73] Adewole, J. A., Adeyemi M. O., Omojola D. I. (2020). Geochemical and mineralogical characteristics of clay deposits at Ijesha–Ijebu and its environs, Southwestern Nigeria. Global Journal of Pure and Applied Sciences. 119-130. DOI: https://dx.doi.org/10.4314/gjpas.v26i2.4.

[74] Ramaswamy S, Raghavan P (2011). Significance of impurity mineral identification in the value addition of kaolin – a case study with reference to acidic kaolin from India. J. Miner. Charact. Eng. 10(11):1007-1025.

[75] Dill, H.G. (2016). Kaolin: Soil, rock and ore: From the mineral to the magmatic, sedimentary and metamorphic environments. Earth Sci. Rev, 161, 16- 129.

[76] Dondi, M. Raimondo, M., Zanelli, C. (2014). Clays and bodies for ceramic tiles: Reappraisal and technological classification. Appl. Clay Sci, 96, 91-109.

[77] Apugo-Nwosu, T. U., Mohammed-Dabo, I. A., Ahmed, A.S., Abubakar, G., Alkali, A.S., Ayilara, S.I. (2011). The suitability of Ubakala Bentonitic clay for oil well drilling mud formulation. British Journal of Applied Science and Technology, 1(4): 152-171.

[78] Ferrari, S., Gualtieri, A. F. (2006). The use of illitic clays in the production of stoneware tile ceramics. Applied Clay Science 32; 73-81.

[79] Bhatacharyya, K. G., Gupta, S. S. (2008). Adsorption of few heavy metals on natural and modified kaolinite and montmorillonite: A review. Advances in Colloid and Interface Science, 140(2):114-131.

[80] Braide, S. P. (1987). Clay mineral burial diagenesis: A case study from the Calabar Flank of the Niger Delta. Journal of African Earth Sciences, 6(2); 18l- 196.

[81] Braide and Huff Braide, S.P., Huff, W. D. (1986). Clay mineral variation in Tertiary Sediments from eastern flank of the Niger Delta. Clay minerals, 21; 211-224.

[82] Eigbike, C.O., Nfor, B. N., Imasuen, I. O. (2013). Physicochemical investigations and health implications of geophagial clays of Edo State, Mid-Western Nigeria. Journal of Geology and Geosciences. 3:140. DOI: http://dx.doi.org/10.4172/2329-6755.1000140.

[83] Eigbike, O.C., Anegbe, B.,Obomese, F., Megbuluba, T. (2016). Geochemical, physico-chemical and mineralogical characterization of clayey soils used traditionally as therapeutic and cosmetic ingredients in Edo State Nigeria. International Journal of Geography and Environmental Management, 2(1); 47-60.

[84] Bertram M. O. (2017). Formation Sensitivity Assessment of the Gbaran Field, Niger Delta Basin, Nigeria. International journal of scientific and technical research in engineering, 2(9); 1-12.

[85] Okogbue, C.O., Ene, E. (2008). Geochemical and geotechnical characteristics and the potential for use in drilling mud of some clay bodies in Southeastern Nigeria. Journal of Mining and Geology, 44(2); 121-130.

[86] Olufemi A. O., Dennis I. O. (2020). Physiochemical Properties of Ajona-Obukpa Clay Mineral for Refractory and Industrial Application. The Pacific Journal of Science and Technology, 21(2); 293- 301.

[87] Njoku, R. E., Ocheri, C. (2020). Influence of Particle Size and Clay Content on some Moulding Properties of Ehalumona Sand Blended with Nkpologu Clay for Sand Casting Applications. Journal of Scientific and Engineering Research, 7(5):40- 47.

[88] Joel, O. F., Nwokoye, C. U. (2010). Performance Evaluation of local Bentonite with imported grade for utilization in oil field operations in Nigeria, refereed proceedings, SPE paper 136957, 34th Annual PE International Technical Conference and Exhibition, in Tinapa, Calabar, Cross River State, July 31- August 7.

[89] Udoh, F.D., Okon, A.N. (2012). Formulation of water based drilling fluid using local materials. Asian Journal of Microbiology and Environmental Sciences, 14(2); 167-174.

[90] Osadebe, C.C., Obrike, S.E., Sulymon, N.A. (2011). Evaluation of Imo clay shale deposit (Paleocene) from Okada, Edo State, South Western Nigeria as drilling mud clay. J. Appl. Technol. Environ. Sanit. 1 (4), 311-316.

[91] Porrenga, D. H. (XX). Clay Mineral in Recent sediments of the Niger Delta.

[92] Ehibor, I. U., Akpokodje, E. G., Tse, A .C. (2019). Geotechnical Properties of Clay Soils in Uyo Town, Eastern Niger Delta, Nigeria. Journal of Applied Geology and Geophysics, 7(3); 08-16.

[93] Nwosu, O.U., Ewulonu, C.M. (2014). Rheological Behaviour of Eco-friendly Drilling Fluids from Biopolymers. J. Polymer Biopolymer Phys. Chem. 2 (3), 50-54.

[94] Ekpunobi U. E., Duru C. B., Ogbuagu A. S. and Obumselu F. O. (2003). Analysis and characterization of clay deposit in Idemili river, south eastern Nigeria. Pelagia Research Library Der Chemica Sinica, 4(3); 6-9.

[95] Olubayode, S.A., Awokola, O.S., Dare, E.O., Olateju, O.T. (2016) Suitability of Some Selected Clay Deposit from Edo, Ogun, Ondo and Ekiti State of Nigeria for Ceramic Water Filters Production. Journal of Minerals and Materials Characterization and Engineering, 4, 26-32. http://dx.doi.org/10.4236/jmmce.2016.41003.

[96] Olusola, J. O., Suraj A. A., Temitope M. A., Aminat, O. A. (2011). Sedimentological and geochemical studies of Maastrichtian clays in Bida Basin, Nigeria: Implication for resource potential. Centrepoint Journal, 17(2); 71-88.

[97] Obi, C., Agha, I. I. (2016). Base – Line Characterization of Unwana Ogwuta Cave (Iyi Ogo) New Site Clay in Afikpo, Ebonyi State. International Journal of Innovative Environmental Studies Research 4(3):1-6.

[98] Oyebanjo, O.M. Ekosse, G.E., Odiyo, J.O. (2018). Mineral Constituents and Kaolinite Crystallinity of the <2 µm Fraction of Cretaceous-Paleogene/ Neogene Kaolins from Eastern Dahomey and Niger Delta Basins, Nigeria, Open Geosci. 2018; 10:157-166.

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Eyankware, M. O., Ogwah, C., & Ike, J. C. (2021). A Synoptic Review of Mineralogical and Chemical Characteristics of Clays in the Southern Part of Nigeria. Research in Ecology, 3(2), 32–45. https://doi.org/10.30564/re.v3i2.3057

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Vol. 3 , Iss. 2 (June 2021)

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