Evaluation of non-destructive tools for preliminary environmental risk assessment during mining exploration

Abstract

Environmental assessment is generally performed when a mining project is at an advanced development stage, such as the prefeasibility study. It involves several laboratory tests such as detailed characterisation and geochemical mobility prediction tests, which require many samples considered representative of the deposit. Having early characterisation information could be useful to select the most relevant samples for the overall environmental assessment. The present study proposes a selection of non destructive and portable tools for improving the early environmental assessment of a mineral deposit. Three tools (x-ray fluorescence (XRF), mineral spectrometer, carbonate staining) were identified to form a preliminary environmental assessment methodology that can be performed directly on the exploration site. This methodology was applied to two different mining projects: i) a well developed mine, LaRonde zone 5, with available geochemical data in a volcanic-associated massive sulfide (VMS) context, and ii) an exploration project, O’Brien, with ongoing geochemical acquisition in an Au-quartz vein context. Both mine sites are in the south of the Blake River Group within the Abitibi greenstone belt, Quebec, Canada. The first site was used to validate the developed methodology, whereas the second acted as a test site to apply the methodology as a preliminary environmental assessment. The results on the first site confirmed that the selected tools provide geochemical and mineralogical data sets comparable to those of traditional testing methods. The developed methodology then enabled the classification of preliminary geo-environmental domains for the second site. Standard static and kinetic tests were performed on the second site samples to confront the preliminary assessment protocol. The proposed preliminary protocol made it possible to discriminate low-risk samples versus those with a potentially higher risk for the selection of subsequent environmental assessments.