A multi-sensor logger for rock cores: Methodology and preliminary results from the Matagami mining camp, Canada

Ross, Pierre-Simon; Bourke, Alexandre; Fresia, Bastien

doi:10.1016/j.oregeorev.2013.01.002

Cited by 44 publications

(34 citation statements)

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“…For example, if the goal is to obtain highspatial resolution downhole geochemical profiles on entire drill holes, then in situ measurements with smoothing (e.g. three to five point moving averages) provide fit-for-purpose data (Ross et al 2013(Ross et al , 2014b.…”

Section: Discussionmentioning

confidence: 99%

“…Instead of taking measurements close together on a core sample and average them, it is possible to take measurements at regular intervals along the core and smooth the data with a 3-point or 5-point moving average (Ross et al, 2013(Ross et al, , 2014b. This assumes that geological units are much thicker than the measurement interval, which would typically be the case for lava flows or thick sills for example.…”

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confidence: 99%

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Portable X-ray fluorescence measurements on exploration drill-cores: comparing performance on unprepared cores and powders for ‘whole-rock’ analysis

Bourke

Ross

2015

GEEA

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One geoscience application of pXRF technology is acquiring 'whole-rock' analyses of unmineralized or weakly mineralized rock cores for major oxides and trace elements, to fill the gaps between traditional laboratory analyses and/or obtain geochemical data more quickly. But the question of whether the samples actually need to be crushed and pulverized before analysis to produce useful results has not been extensively studied. In this paper pXRF data quality is compared on unprepared rock cores and on powders in three ways: instrumental precision (relative standard deviation, RSD, of a series of measurements on the same spot), sample precision (for unprepared samples, RSD of a series of measurements on different spots on the core), and accuracy (average pXRF value versus laboratory geochemistry). Two Olympus Innov-X Delta Premium pXRF devices were tested on 27 core samples of dense, non-mineralized, fine-to medium-grained, Precambrian volcanic and intrusive rocks from Canada. In general, sample preparation does not improve instrumental precision or accuracy. The significant advantage of powders is to avoid mineralogical heterogeneity. However sample precision for in situ data is improved by averaging multiple measurements of different points on the sample: a significant gain is obtained between three and seven measurements. The sample precisions at 25 points -which is about the most measurements one can make during the same amount of time used for powdering a rock core sample -are better than the instrumental precision on powders for most elements. For high spatial resolution downhole element profiles on entire drill holes, in situ pXRF measurements with smoothing (e.g. three to five point moving averages) provide fit-forpurpose data; the alternative of turning the entire drill-core into powder is not realistic.. INTRODUCTIONDiamond drilling is a major component of advanced mining exploration programs. Two types of traditional laboratory geochemical analyses are often performed on exploration drill-cores by the mining industry, geological surveys and university researchers: (1) assays of mineralized or potentially mineralized samples, for elements such as base metals, precious metals, rare earth elements, etc. (e.g. Moon et al. 2006); and (2) 'whole-rock' analyses of unmineralized or weakly mineralized samples for major oxides and trace elements (e.g. Ross 2010; Mercier-Langevin et al. 2014;Rogers et al. 2014). The first type of analysis is carried out within selected intervals, often on c. 1 mlong sections of split or cut cores, to quantify the grades of orebodies. The second type of analysis can be

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Portable X-ray fluorescence measurements on exploration drill-cores: comparing performance on unprepared cores and powders for ‘whole-rock’ analysis

Bourke

Ross

2015

GEEA

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“…Alternative core logging or imaging systems exist in academic and commercial settings (some are reviewed and compared by Ross et al, 2013), but they do not integrate all of these parameters. Although in this study we have performed our measurements on drill cores that were several years old, it should be possible to integrate the multi-parameter logging in the exploration workflow before the visual description by geologists.…”

Section: Discussionmentioning

confidence: 99%

“…The logger also acquires a continuous image of the core using a line-scan camera. Our methods have been described in detail by Ross et al (2013Ross et al ( , 2014bRoss et al ( , 2014c and references therein, with recent improvements for geochemistry presented by Bourke and Ross (2015). LEM-37 is a 894.2 m-long BQ (3.7 cm diameter core) drill hole; the cored portion starts at 5.5 m, for a total core length of 888.7 m. We have obtained a total of 3486 measurements of density, magnetic susceptibility, and infrared spectrometry in this hole, for a downhole resolution (average measurement spacing) of 25.5 cm.…”

Section: Methodsmentioning

confidence: 99%

“…For high-resolution measurements of physical properties, geochemistry and mineralogy, one solution is to use a multi-sensor core logger (MSCL) housed in a mobile laboratory (Ross et al, 2013). The laboratory is utilized on core storage sites, and its non-destructive technology could potentially be used before geologists examine the cores and sample them, allowing for less subjective, more homogeneous core logs.…”

Section: Introductionmentioning

confidence: 99%

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High-Resolution Physical Properties, Geochemistry, and Alteration Mineralogy for the Host Rocks of the Archean Lemoine Auriferous Volcanogenic Massive Sulfide Deposit, Canada

et al. 2016

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Multi-parameter data on drill cores has a range of useful applications for ore deposit modeling and mineral exploration. Density, magnetic susceptibility, eight major elements, seven trace elements (portable X-ray fluorescence, pXRF), five mineral groups (near-infrared spectrometry) and average visible light reflectance were determined on rock cores from several drill holes. These are located near the Archean Lemoine auriferous volcanogenic massive sulfide (VMS) deposit in the Chibougamau mining district, Abitibi Subprovince, Quebec, Canada. This case study focuses on one drill hole in particular which has been recently characterized in detail by conventional methods (laboratory geochemistry, petrography, stable isotopes); this provides validation for the multi-sensor dataset. The best variables and immobile element ratios to distinguish between different lithological units in the multi-parameter data are density, magnetic susceptibility, Ti/Zr, Al/Zr, and Zr/Y. Downhole profiles of these parameters allow the four different felsic units in LEM-37, many of which are visually similar, to be distinguished, and geological contacts to be positioned precisely. Such methods would be even more useful in environments where recognition of primary characteristics is strongly hampered by intense hydrothermal alteration and superimposed deformation or metamorphism. Volcanic and intrusive rocks can be placed on classic diagrams to assign them names and magmatic affinities based on the corrected pXRF data. Downhole profiles of major and trace elements, combined with infrared mineralogy, allow hydrothermal alteration to be characterized, yielding results comparable to those of conventional techniques for the same drill hole, but with a much tighter spacing and within potentially shorter timeframes.

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Geochemistry of uranium-bearing rocks in the regions of Oued El Foula and Ain Sder

Welaty,

Maghlah,

Biha

et al. 2024

Arab J Geosci

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A multi-sensor logger for rock cores: Methodology and preliminary results from the Matagami mining camp, Canada

Cited by 44 publications

References 10 publications

Portable X-ray fluorescence measurements on exploration drill-cores: comparing performance on unprepared cores and powders for ‘whole-rock’ analysis

Portable X-ray fluorescence measurements on exploration drill-cores: comparing performance on unprepared cores and powders for ‘whole-rock’ analysis

High-Resolution Physical Properties, Geochemistry, and Alteration Mineralogy for the Host Rocks of the Archean Lemoine Auriferous Volcanogenic Massive Sulfide Deposit, Canada

Geochemistry of uranium-bearing rocks in the regions of Oued El Foula and Ain Sder

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