Sébastien Blais-Ouellette

Photonic Knowledge, Inc., a spin-off of Photon etc., introduces the Core Mapper

 , a hyperspectral imager that produces instantaneous, precise in situ mineralogy, lithology, and alteration mapping. This unique patented technology answers the increasing demand of the mining industry for better exploration tools. 

Based on Photon etc's hyperspectral imaging technology the Core Mapper™ delivers a series of monochromatic images at user-specified wavelengths between 400 and 1000 nm, offering instant in situ mineral identification. The hyperspectral imager simultaneously analyses five drill core boxes with a spatial resolution of 1 mm

 . Spatial resolution is 900 times better and field of view is 1666 times wider than any currently available hand-held mineral spectrometer. It can provide fast mineralogy fields mapping services, as high as 1500 drill core meters per day with one imager. 

Using the optimized Hyperspectral Imager designed specifically for mineral identification, Photonic Knowledge demonstrated the unique precision of the Core Mapper™ to a mine site in the Rouyn-Noranda region (Figure 1).

 Figure 1: Transportable laboratory setup.			

Two drilling holes were dug and assessed. Gold analysis performed on the core of the first hole indicated gold values averaging 5 to 7 g/ton. The second hole was only partially sampled based on the geologist's assessment and labelled "of limited interest." No supplementary gold assays were performed on the second hole. 

 Optical spectra provide crystal field characteristics of transition metals, lathanides, actinides, and spectro-chemical clues on ligand contents. Using the Core Mapper™, Photonic Knowledge identified proper weighting of spectral classes vectorizing the gold mineralization on the first hole. This algorithm was then applied to the second hole and the same gold vectors were identified. Assays were subsequently performed on samples from the second hole yielding 0.1 g/ton to 0.5 g/ton, averaging 0.2 g/ton on 5 meters illustrating the accuracy and detection limit of the Core Mapper™ as well as the high potential for ore vectorization (Figure 2). Although subeconomic, this finding was significant as an indicator of proximity to the main mineralization zone.

Figure 2: Example of ore vectorization.			

Resulting in more than just an increase in efficiency, the Hyperspectral Imager supplies information on both spectral and spatial content, creating new opportunities for analysis, pushing the boundaries of the most demanding applications in mineral identification. Photonic Knowledge's optimized hyperspectral cube allows for spectral analysis of each and every pixel of a full resolution image, amounting to no more fastidious 

The Core Mapper™ technology affords the mining industry the opportunity to see things never seen before. The precision and speed with which it performs diagnostics of material, physical, or molecular is unparalleled. With a single acquisition, the photonic imaging system discovers gold bearing zones in a way geologists have only dreamed about!  

5795, Gaspé, #222, Montreal, Quebec, H2S 2X3, Canada

tel. (514) 385-9555, fax (514) 279-5493  

481 Grande-Côte, Rosemère, Quebec, J7A 1M1, Canada

Articles

Photonic Knowledge, Inc., a spin-off of Photon etc., introduces the Core Mapper?, a hyperspectral imager that produces instantaneous, precise in situ mineralogy, lithology, and alteration mapping. This unique patented technology answers the increasing demand of the mining industry for better exploration tools.

Finding Gold Just Became Easier than Ever Imagined

Marc Verhaegen and Sébastien Blais-Ouellette,

Photon etc. has designed two narrowband tunable filters for resonance Raman spectroscopy. These matched tunable passband and notch filters, based on thick volume Bragg gratings, exhibit a bandwidth less than 10 cm

  and cover a wavelength range of several hundreds of nanometers. 

Raman spectroscopy (RS) is a powerful tool to study vibrational, optical, and electronic properties of materials in a nondestructive manner. Raman signals are typically orders of magnitude lower than the intensity of the excitation laser line (1). However, it is possible to significantly increase Raman signals by choosing an excitation wavelength that corresponds to an optical transition of the material under investigation. 

Resonant Raman Spectroscopy (RRS) provides a unique tool to characterize the diameter and chirality distribution of a mixed population of carbon nanotubes (CNT). RRS is also a powerful method to monitor in-situ the CNT properties during growth. Thus, it can serve as a diagnosis tool in order to achieve better control of the CNT production.  

Using volume Bragg grating (VBG) technology, Photon etc. has developed, specifically for RRS, two types of ultra narrow band tunable filters: a laser line filter and a notch filter. 

The Laser Line Tunable Filter (LLTF) is installed just after the Tunable Ti:Saph laser (Figure 1) and blocks the unwanted fluorescence produced by the laser, leaving the excitation laser line untouched. Two steering mirrors (M1 and BS) send the laser line into a standard microscope where the laser beam is focused on the sample of interest. 

Figure 1: Experimental setup for Raman characterization.			

The second filter, a Tunable Top Notch™ Filter (TTNF), is installed after the microscope. The TTNF blocks the Rayleigh scattering coming from the material, leaving the Raman signal untouched down to 50 cm

The tunable filters are controlled by a computer via USB links, allowing fast wavelength selection. 

Stokes and anti-Stokes Raman spectra of single-walled carbon nanotube (SWNT) powder (Figure 2) were measured within less than 1 h using a standard spectrometer (2). Each peak corresponds to a radial breathing mode (RBM), and the center frequency of a given peak is inversely proportional to the nanotube diameter of a given population. Several populations of nanotubes with different diameters can therefore be readily observed and effectively characterized. 

Figure 2: Raman spectra of CNT using Ti:Saph laser and TTNF.			

(1) J. R. Ferraro, K. Nakamoto, and C. W. Brown, 

(2) M. Paillet, F. Meunier, M. Verhaegen, S. Blais-Ouellette, and R. Martel, 

5795, avenue de Gaspé, #222, Montreal, Quebec, H2S 2X3

Photon etc. has designed two narrowband tunable filters for resonance Raman spectroscopy.

Sébastien Blais-Ouellette

Articles

Finding Gold Just Became Easier than Ever Imagined

Carbon Nanotube Characterization by Resonance Raman Spectroscopy