Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery

Abstract The severe drought of 1983–1984 in the Sahel region, and its socio‐economic impacts for people relying on farming had for consequence the first major gold rush at Koma Bangou in the southwestern part of Niger. Initiated in 1984, the gold panning activities were interrupted from 1989 to 1999...

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Autores principales:	A. Abass Saley, D. Baratoux, L. Baratoux, K. E. Ahoussi, K. A. Yao, K. J. Kouamé
Formato:	article
Lenguaje:	EN
Publicado:	American Geophysical Union (AGU) 2021
Materias:	Koma Bangou gold panning waste Landsat imagery feature oriented principal component selection Astronomy QB1-991 Geology QE1-996.5
Acceso en línea:	https://doaj.org/article/a6010c61a03c4ec0b00734817aae59de
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spelling	oai:doaj.org-article:a6010c61a03c4ec0b00734817aae59de2021-11-23T21:03:07ZEvolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery2333-508410.1029/2021EA001879https://doaj.org/article/a6010c61a03c4ec0b00734817aae59de2021-11-01T00:00:00Zhttps://doi.org/10.1029/2021EA001879https://doaj.org/toc/2333-5084Abstract The severe drought of 1983–1984 in the Sahel region, and its socio‐economic impacts for people relying on farming had for consequence the first major gold rush at Koma Bangou in the southwestern part of Niger. Initiated in 1984, the gold panning activities were interrupted from 1989 to 1999 with exploration permits assigned to the mining industry. The site was reclassified at the year‐end 1999 as a gold panning site and artisanal mining resumed until present‐day. Gold panning activities such as ore extraction and cyanide processing produced mining waste including rocks, mine tailings, and treatment residues. Mining waste is a serious environmental, health and safety problem. Multispectral Landsat images (TM4‐5, ETM7+, OLI/TIRS) acquired between 1984 and 2020 were used to map the spatial evolution of waste generated by gold panning activities at Koma Bangou. Different processing methods were tested, including Minimum Noise Fraction (MNF) transform, Band Ratio (BR), and Feature Oriented Principal Component Selection (FPCS). The FPCS applied to hydroxyl‐bearing minerals appears to be most efficient to map gold extraction and cyanidation waste areas. The waste surface associated with ore extraction has increased from 9.43 ha in 1984 to 234.20 ha in 2020, with continuous expansion during the period of clandestine activity (1989–1999). The waste surface associated with cyanidation has increased from 5.56 ha in 2009 (the year of cyanide treatment introduction) to 99.53 ha in 2020. Landsat multispectral imagery proved a suitable data source for monitoring the evolution of gold mining waste and consequences of public policies at Koma Bangou.A. Abass SaleyD. BaratouxL. BaratouxK. E. AhoussiK. A. YaoK. J. KouaméAmerican Geophysical Union (AGU)articleKoma Bangougold panningwasteLandsat imageryfeature oriented principal component selectionAstronomyQB1-991GeologyQE1-996.5ENEarth and Space Science, Vol 8, Iss 11, Pp n/a-n/a (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Koma Bangou gold panning waste Landsat imagery feature oriented principal component selection Astronomy QB1-991 Geology QE1-996.5
spellingShingle	Koma Bangou gold panning waste Landsat imagery feature oriented principal component selection Astronomy QB1-991 Geology QE1-996.5 A. Abass Saley D. Baratoux L. Baratoux K. E. Ahoussi K. A. Yao K. J. Kouamé Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery
description	Abstract The severe drought of 1983–1984 in the Sahel region, and its socio‐economic impacts for people relying on farming had for consequence the first major gold rush at Koma Bangou in the southwestern part of Niger. Initiated in 1984, the gold panning activities were interrupted from 1989 to 1999 with exploration permits assigned to the mining industry. The site was reclassified at the year‐end 1999 as a gold panning site and artisanal mining resumed until present‐day. Gold panning activities such as ore extraction and cyanide processing produced mining waste including rocks, mine tailings, and treatment residues. Mining waste is a serious environmental, health and safety problem. Multispectral Landsat images (TM4‐5, ETM7+, OLI/TIRS) acquired between 1984 and 2020 were used to map the spatial evolution of waste generated by gold panning activities at Koma Bangou. Different processing methods were tested, including Minimum Noise Fraction (MNF) transform, Band Ratio (BR), and Feature Oriented Principal Component Selection (FPCS). The FPCS applied to hydroxyl‐bearing minerals appears to be most efficient to map gold extraction and cyanidation waste areas. The waste surface associated with ore extraction has increased from 9.43 ha in 1984 to 234.20 ha in 2020, with continuous expansion during the period of clandestine activity (1989–1999). The waste surface associated with cyanidation has increased from 5.56 ha in 2009 (the year of cyanide treatment introduction) to 99.53 ha in 2020. Landsat multispectral imagery proved a suitable data source for monitoring the evolution of gold mining waste and consequences of public policies at Koma Bangou.
format	article
author	A. Abass Saley D. Baratoux L. Baratoux K. E. Ahoussi K. A. Yao K. J. Kouamé
author_facet	A. Abass Saley D. Baratoux L. Baratoux K. E. Ahoussi K. A. Yao K. J. Kouamé
author_sort	A. Abass Saley
title	Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery
title_short	Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery
title_full	Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery
title_fullStr	Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery
title_full_unstemmed	Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery
title_sort	evolution of the koma bangou gold panning site (niger) from 1984 to 2020 using landsat imagery
publisher	American Geophysical Union (AGU)
publishDate	2021
url	https://doaj.org/article/a6010c61a03c4ec0b00734817aae59de
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Evolution of the Koma Bangou Gold Panning Site (Niger) From 1984 to 2020 Using Landsat Imagery

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