Raymax new technologies like HySpex hyperspectral core scanning, advance the analysis of ‘green minerals’.

Mineral exploration plays an important role in society. Today, with the drive for a low carbon economy there is pressure to discover mineral deposits such as nickel, lithium, cobalt, zinc and copper that are required to build renewable energy sources such as solar panels, wind turbines and batteries for homes, industry and electric vehicles. Without access to ‘green metals’ a low-carbon world won’t be possible.

In support of mineral exploration are two technologies that offer improved mineral identification techniques through reliable analysis. One of these technologies is LIBS or Laser Induced Breakdown Spectroscopy. A rapid minimally destructive chemical analysis technique used to identify and detect mineralogical samples. A leading laser system is the J200 LIBS instrument from Applied Spectra designed specifically to handle the most demanding trace element analyses — those requiring high sensitivity and accuracy. With a single-digit ppm (parts per million) level of detection (LOD) limit for many elements in the periodic table, the J200 LIBS is an ideal instrument for challenging quantitative elemental analysis with many sample matrices and capable of monitoring single or multiple elements of analytical interest.

“Already Australian organisations are applying LIBS to analyse the chemical construct of sample rocks for the detection the mineralogical content,” says Chris Lay, from Raymax Applications Pty Ltd which distributes Applied Spectra Inc laser systems. “Using LIBS has enabled the identification of essential mineral deposits and even enable better mapping of mine sites,” Lay added.

LIBS technology advances existing technologies currently used for the direct analysis of mineralogical samples such as infrared spectroscopy or IR. However, while IR identifies the mineralogy of a rock sample it does not identify the elemental composition such as rare earth elements (REEs) needed for the identification and mining of ‘green minerals.’ XRF is a technology currently used to determine the concentration of basic metals such as copper, zinc, and nickel. However, XFR is known to be challenged when it comes to quantifying precious metals such as gold due to the low sensitivity and poor limit of detection. Additionally, portable X-ray systems used in situ in the field, have shown they are not sensitive enough to detect gold, for example in the ppm range – or parts per million, and often incur substrata interference with other minerals giving false values compromising determinations.

Compared to XRF techniques, the J200 LIBS instrument developed by Applied Spectra, offers attractive analytical advantages to the mining industry, detecting elements from H – Pu, including non-metals such as H, N, F and O, that are often difficult or impossible to discern with other types of analysis. The J200 LIBS laser system can measure a large number of elements, simultaneously as well as detecting lighter elements such as B, Li, C, K, Ca, Mg, Al, Si, etc, that are beyond the capabilities of other techniques. “Little to no sample preparation is required, meaning quick access to the system for analysis using Applied Spectra’s software package. Precise elemental analysis is fast, for instance, a single spot analysis can be achieved in a few seconds,” Lay says. The J200 laser system offers high reliability for important elemental analysis. To support this highly complex process Applied Spectra has developed very powerful chemometric software for LIBS data analysis: Principal Component Analysis. “What we are seeing is that accurate, effective LIBS elemental analysis, has the potential to revolutionise the mining industry,” said Lay who would be delighted to explain the LIBS process and its importance to mining ‘green minerals’ to members of the mining industry. In addition, Lay can explain the process of laser ablation in the J200 Tandem LA-LIBS instrument of capturing the emitted light from laser ablation plasma for rapid spectroscopic analysis.

A second and complementary technology is hyperspectral imaging, offered by HySpex NEO an established industry-leading brand for both airborne and ground-based hyperspectral imaging supplied by Raymax Applications for customers in Australasia. This powerful tool is used in various fields revolutionising the way we analyse and understand materials. One application is in core scanning a technique used to analyse the composition and properties of sediment and rock cores. With a growing demand on ‘green’ metals essential for producing low-carbon technologies such as electric cars and smartphones, a variety of natural resources have assumed greater importance in mining, increasing the demand for better samples from mine sites for geological analysis to achieve more accurate, detailed mineral maps.

Traditional core scanning methods often rely on visible light or limited wavelength bands to identify and characterize core samples. Hyperspectral imaging takes this process to a whole new level by capturing a spectrum of information for each pixel in an image. Instead of just a few discrete colour channels, hyperspectral systems collect data across hundreds of narrow and contiguous spectral bands. This results in a detailed spectral fingerprint for each pixel, providing unparalleled insights into the composition and distribution of materials within the core.

Image: Core and rock samples ready for analysis at HySpex NEO Applications Lab

Using HySpex NEO hyperspectral imaging systems for core scanning has several key advantages. First, it allows the identification and differentiation of minerals, organic matter, and other components that might be challenging to distinguish using conventional methods leading to more accurate lithological and mineralogical classifications, aiding in the interpretation of geological history and environmental conditions. Second, hyperspectral imaging enables the detection of subtle changes in composition particularly valuable for identifying variations in mineralogy, porosity, and other physical properties across the length of a core sample.

In addition, using HySpex hyperspectral core scanning can provide insights into environmental conditions and processes. However, the use of hyperspectral imaging for core scanning also presents challenges. The vast amount of spectral data generated requires sophisticated data analysis techniques to extract meaningful information. This demands specialized software and algorithms that can process, interpret, and visualise multidimensional data effectively. To meet this requirement, HySpex has partnered with Prediktera, whose premiere software solution, Breeze, enables a wide range of hyperspectral imaging applications for application development, routine analysis and real-time industrial analysis solutions.

“This complimentary technology to LIBS for core drill analysis incorporates HySpex VNIR and SWIR cameras which provide scientific-grade hyperspectral imagery,” explains Dr Cédric Chaminade from Raymax Applications, “Working together with the new Breeze Geo software tools, mineral mapping of the highest quality and highest resolution can now be undertaken.” In addition, the platform is linked to the USGS libraries and allows for mineral identification and quantification using many customisable algorithms such as minimum wavelength mapping, and spectral angle mapper, providing great resources for the end user.

HySpex NEO’s drill core scanner allows you to achieve a seamless user experience as the tools to implement hyperspectral imaging of mineral analysis in the laboratory, core shed, mine site, or even a mineral processing environment are provided with the hardware. Real-time interpretation and visualization of the scanned cores identifies areas of significance, such as alteration mineralization, and highlighting sections requiring assay or geochemical sampling. The resulting mineralogic interpretation can be optimized for core boxes, it can handle drill chip boxes, loose samples, and rock mass.

Due to the quality of data acquisition, hyperspectral imaging will minimise misclassification of false allocations of material that may have yielded itself using other technologies such as hand-held devices or lower fidelity and resolution systems. “With HySpex NEO cameras,” says Dr Chaminade, “Each pixel in a hyperspectral image has a continuous spectrum, a technique that has wide geological applications, including the identification and classification of mineralogical alteration assemblages and correlation of geological units.” Using VNIR and SWIR cameras, imaging spectroscopy can help both identify and evaluate mineral or deposit-specific geological materials. The data can also provide planning information in the form of a 3D model to help with on-the-ground activities, prior to extraction.

“At Raymax, we have extensive experience with HySpex NEO cameras, in the field, at mine sites, and for agricultural and defence applications. But the opportunities to assist with mining ‘green minerals’ to help the carbon-free economy is very exciting,” concludes Dr Chaminade.