Combined mineralogy and chemistry on drill cores: challenging for on-line-real-time analyses

Cédric Duée (1) , Nicolas Maubec (1) , Valérie Laperche (1) , Laure Capar (1) , Anne Bourguignon (1) , Xavier Bourrat (1) , Yassine El Mendili (2) , Daniel Chateigner (2) , Stéphanie Gascoin (2) , Gino Mariotto (3) , Marco Giarola (3) , Arun Kumar (3) , Nicola Daldosso (3) , Marco Zanatta (3) , Adolfo Speghini (3) , Andrea Sanson (4) , Luca Lutterotti (5) , Evgeny Borovin (5) , Mauro Bortolotti (5) , Maria Secchi (5) , Maurizio Montagna (5) , Beate Orberger (6, 7) , Monique Le Guen (7) , Anne Salaün (7) , Céline Rodriguez (7) , Fabien Trotet (7) , Mohamed Kadar (7) , Karen Devaux (7) , Henry Pillière (8) , Thomas Lefèvre (8) , Fons Eijkelkamp (9) , Harm Nolte (9) , Peter Koert (9) , Saulius Grazulis (10)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
3 UNIVR | DI - Department of Computer Science [Verona]
4 Unipd - Università degli Studi di Padova = University of Padua
5 UNITN - Università degli Studi di Trento = University of Trento
6 GEOPS - Géosciences Paris Sud
7 ERAMET - ERAMET
8 ThermoFisher Scientific
9 Royal Eijkelkamp
10 Vilnius University [Vilnius]

In order to evaluate the instrumental parameters for the combined on-line-on-mine-real-time expert system SOLSA (http://www.solsa-mining.eu), portable and laboratory analyses were carried out on coarse granite, sandstone, serpentinized harzburgite and siliceous breccia. Each sample was studied at 5 different surface roughnesses (sonic or diamond drilled, cut, polished at 6 µm and 0.25 µm, sample powders). X-ray diffraction (XRD), portable Infra-Red (pIR) and X-ray-fluorescence (pXRF), and laboratory micro-Raman spectroscopy gave complementary and corroborating results. No major effect on the analyses was noted for the selected surface states. pXRF gave variable results except for the homogeneously serpentinized harzburgite, related to coarse or contrasting grain sizes or pores, small spot size (3 mm) and needs close-to-surface analyses. Portable IR (spot size 1.76 cm 2) is carried out close to surfaces while Raman spectroscopy (1-2 µm) is performed at distance. Sampling strategies have to be defined for each lithology. Major challenges for a combined on-line analysis are to adapt the specificities of the techniques to (1) analyse similar surface areas (from ~2 cm 2 (pIR) to < µm (Raman)), (2) smartly combine all the techniques into a single instrument, and (3) develop appropriate databases to reach a reliable " real-time " outcome results, which can be used for more precise geomodeling, and to rapidly define exploration and beneficiation parameters.

Domaines: Géochimie

Cédric Duée, Nicolas Maubec, Valérie Laperche, Laure Capar, Anne Bourguignon, et al.. Combined mineralogy and chemistry on drill cores: challenging for on-line-real-time analyses. SGA Québec 2017, 14th biannual meeting, Aug 2017, Québec City, Canada. ⟨hal-01536653⟩