Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation Georesources & Geo-Imaging Research Group Georesources & Geo-Imaging Research Group © CSIRO Quantitative Microscopy On Line Vision Core Scanning 3D particle size & shape

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Range 50µm -> 5mm particles/min o Mechanical dispersion Vibration (tray) Acceleration (conveyor) o Suction Laminar air flow Free flowing powders Free flowing powders

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Range 500nm - 150µm particles / min Vacuum dispersion For dry powders Flow cell For wet powders suspensions emulsions,… Non free flowing powders Non free flowing powders

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Estimation of chromite content in UG2 slurries o Modified flow cell Identification of chromite grains (opaque) Real time estimation of chromite content and liberation Size and Mineralogy Size and Mineralogy 5 [chromite] from AA [chromite] from IMAGE

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Existing spectral databases o Specular reflectance of ore-forming minerals QDFIII 400nm-700nm (Criddle & Stanley, 1993) Extended to 1000nm (Brea et al., 2010) Mineralogy & Particle Size Mineralogy & Particle Size 6

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Existing spectral databases o Diffuse reflectance of rock forming minerals Speclab USGS, Grove et al. (1992) Mineralogy & Particle Size Mineralogy & Particle Size 7 < 45 µm < 125 µm < 500 µm Chalcopyrite Pyrite Specular (QDFIII)

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Best of both worlds o Diascopic imaging for opaques White LED illumination o Episcopic imaging Selected LEDs Eight wavelength Dichroic mirrors Dark field objective Multispectral Set Up Multispectral Set Up 8

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Gangue Silicates vs Sulphides Diascopic Imaging Diascopic Imaging 9

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Oxides vs Sulphides Episcopic Darkfield RGB Imaging Episcopic Darkfield RGB Imaging 10

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Chromite vs Pyrite o Photonfocus MV1 D1312ie 1312x1082 (binning) 3,1 µm/pixel 400 ms Episcopic Darkfield Spectral Imaging Episcopic Darkfield Spectral Imaging 11 Backlit image F0=405 nm F1=455 nm F3=590 nm F4=617 nm F2=530 nm F5=735 nm F6=950 nm

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Darkfield imaging o Reflectance angles Maximum reflectance depends on particle shape and λ Calibration and discrimination Calibration and discrimination Cu wire Ø=100 µm

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Darkfield imaging o Pyrite vs. Copper Percentile P 80 of intensity distribution within particle Combination of > P 80 per wavelength Discrimination Discrimination Pixels voted > P 80 for every λ Pyrite Ø=52 µm Mask P 80 Cu wire Ø=100 µm P 80 P 99 Raw spectrum

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement LYSC: Pyrite-rich (> 91%) LYSB: Mixed sulphides (Py+Cp+…) Particle sizing vs. 405nm/617nm band ratio Discrimination Discrimination Pyrite-rich (LYSC ) Mixed sulphides (LYSB) Pyrite-rich (LYSC ) Mixed sulphides (LYSB)

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement LYSC: Pyrite-rich (> 91%) LYSB: Mixed sulphides (Py+Cp+…) Particle sizing vs. 455nm/617nm band ratio Discrimination Discrimination Pyrite-rich (LYSC ) Mixed sulphides (LYSB) Pyrite-rich (LYSC ) Mixed sulphides (LYSB) Py Cp

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement LYSC: Pyrite-rich (> 91%) LYSB: Mixed sulphides (Py+Cp+…) Particle sizing vs. 405nm/617nm band ratio Discrimination Discrimination Pyrite-rich (LYSC ) Mixed sulphides (LYSB) Pyrite-rich (LYSC ) Mixed sulphides (LYSB) Grey sulphide (sphalerite, galena, arsenopyrite,…) (tbc) Yellow sulphides mix (pyrite,chalcopyrite,…)

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Improved flow cell imaging system o Combined dia- and episcopic imaging o Particle size, shape + mineralogy, (liberation) Multispectral imaging o Simple and flexible o Tunable to dedicated minerals Image processing o Spectra of brightest pixels (> P 80 ) to limit size and shape influence Mineralogy o Band-ratio discrimination Online mineralogy Online mineralogy 17

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Mineralogical Analysis o Needs further calibration o Cross-validation with chemistry and XRD Discrimination limits o Gangue Carbonates vs. Silicates o Sulphides Cp, Py, Ga, Sp, Po,… o Oxides Hem vs. Goe; Ilm vs. Lcx vs. Rut; … Sample Preparation o Dilution needed for dirty and dense pulps Multimodal imaging o Add other imaging modules (i.e. SWIR, Raman,…) Online mineralogy Online mineralogy 18

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement See you in Liège in 2015 See you in Liège in Liège, Belgium