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TitreLake sediment grab sampling versus coring for environmental risk assessment of metal mining
TéléchargerTéléchargements
AuteurAlpay, S; Alpay, R J; Grenier, A; Gould, W D
SourceCommission géologique du Canada, Présentation scientifique 26, 2014, 1 feuille, https://doi.org/10.4095/295559
Image
Année2014
ÉditeurRessources naturelles Canada
RéunionGeological Association of Canada - Mineralogical Association of Canada Joint Annual Meeting; Fredericton; CA; mai 21-23, 2014
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.4095/295559
Mediaen ligne; numérique
Référence reliéeCette publication est reliée Alpay, S; McNeil, R J; Grenier, A; Gould, W D; (2014). Lake sediment grab sampling versus coring for environmental risk assessment of metal mining, L'Association géologique du Canada-L'Association minéralogique du Canada, Réunion annuelle conjointe, Recueil des résumés vol. 37
Formatspdf
ProvinceQuébec
SNRC32D/03; 32D/06
Lat/Long OENS-79.5333 -79.2000 48.3500 48.0000
Sujetsetudes de l'environnement; effets sur l'environnement; méthodes d'exploitation minière; exploitation minière; contamination des métaux lourds; cuivre; zinc; or; argent; Mine Aldermac ; géologie économique; géologie de l'environnement
Illustrationslocation maps; photographs; plots; tables
ProgrammeOutils d'adaptation et d'impacts sur l'environnement pour les mines de métaux, Géosciences de l'environnement
Diffusé2015 05 06
Résumé(disponible en anglais seulement)
Current practices for baseline studies of sites to be developed for mining include surface grab sampling of sediments in aquatic receiving environments. In contrast, vertical sediment coring is a universal tool of paleolimnological research. This study evaluates the effectiveness of sediment grab sampling versus sediment coring for environmental risk assessment of metal mining. The former Aldermac mine (Cu, Zn, Au and Ag), 25 km west of Rouyn-Noranda in Abitibi, Quebec, operated from 1932-1943 and discharged acid mine drainage to the watershed downstream. The study site is representative of both a common mineral deposit and the legacy of historical mining practices. Contamination and adverse effects on aquatic habitats were demonstrated to the point where the government of Quebec led an environmental restoration of the Aldermac property (2008-11). Further mining development is foreseeable in the watershed. Surveys of sediment grab samples (2011-13) were done by Petite Ponar® with a penetration depth of approximately 5-10 cm at 32 sites. Co-located sediment coring surveys were conducted using a 10-cm diameter gravity corer, modified with extension rods, to a sediment depth of 30-45 cm. Cores were sub-sampled at discrete depth intervals in two exercises: one survey with a larger regional distribution and thicker sediment slices (32 sites) and the other at 1-cm interval sections at 5 sites for detailed study. Grab sampling generated rapid results that permitted estimates of the current environmental reference state (baseline before new development), metal contaminant sources, and the spatial extent of metal contamination. Sediment coring produced estimates of naturally-occurring metal concentrations (pre-industrial background), the current baseline metal concentrations, metal contaminant sources, the duration of contamination, and its spatial extent. Although surveys of surface sediment grabs are faster and simpler and provide more sample material, they are imprecise snapshots without temporal scales. Sediment coring offers chronology of metal contaminant deposition, more precision, and potential for more targeted data (e.g., to fingerprint metal contaminant sources, assess diagenetic metal mobility, determine stability of metal-bearing phases). Cores can be taken in a reasonably rapid and simple manner, but less efficiently than grab sampling with less sample material for each core slice if sub-sampled at high resolution. Grab sampling offers a first approximation that may be sufficient for an initial environmental risk assessment. However, when further investigation is warranted, sediment coring can be optimized for efficiency and provide insight into accumulated metal contamination over time and an estimate of the range of metal levels in a naturally mineralized region (natural background).
Résumé(Résumé en langage clair et simple, non publié)
Différentes méthodes d'échantillonnage de sédiments aquatiques en aval d'un site contaminé connu (l'ancienne mine Aldermac, en Abitibi, Québec) sont présentées pour démontrer les options pour l'évaluation du risque environnemental des mines de métaux. L'échantillonnage de sédiments en vrac peu profondes est rapidement et les résultats estiment les conditions de base (avant nouveau développement), les sources de contamination, et l'étendue spatiale de la contamination, bien que la méthode génère des données imprécises sans la dimension temporelle. Quand l'étude plus avancée est nécessaire, les carottes de sédiments fournissent la contamination de métaux accumulée au fil du temps, une plus grande précision, et des données plus ciblées (par exemple, pour identifier les sources de contamination et la mobilité des métaux).
GEOSCAN ID295559