Guidelines for Geologists: Revolutionizing Mining Operations with Advanced Ore Analysis Technologies

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Xuan-Ce Wang

26/01/2024

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The mining industry, one of the world's largest industrial sectors, plays a crucial role by providing essential minerals for human daily life. In the process of mineral extraction, known as mineral processing, raw ores are transformed into valuable concentrates beneath the Earth's surface. Geologists play a vital role in optimizing mining operations through the critical analysis of ores.

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1. Fire Assay Method for Ore Analysis: The Industry Standard

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The fire-assay method stands as the industry standard for analyzing gold, silver, and platinum ores in mining. This method involves three stages: smelting the ores with fluxes, isolating precious metals from metallic lead, and analyzing the obtained metals. Finely ground ore is mixed with glass fluxes, litharge, and a carbon source, smelted in a ceramic crucible at temperatures between 900 to 1100 °C. The reduction in lead oxide results in the formation of a lead button collecting precious metals. Precious metals are isolated using magnesium oxide or calcium oxide cupels in the cupellation process.

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2. Wet Assay Ore Analysis Technique

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Wet metal assay techniques involve transforming the ore into powder and dissolving it in a liquid, typically an acid or a combination of acids. The peculiarities of the precipitate produced when a reagent is added to the solution help recognize the presence of known metals. For ores containing sulfur, arsenic, or other volatile substances, powdering and roasting are recommended to eliminate sulfur, leaving metallic portions in oxide form for examination.

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3. Total Reflection X-Ray Fluorescence Spectrometry for Elemental Analysis

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Total reflection X-Ray fluorescence (TXRF) spectrometry is a recent method efficient in determining trace amounts of minerals in ores. TXRF has been applied to elemental analysis in sulfur ores, depicting its effectiveness. A suspension is prepared for TXRF analysis using 5 mL of 1% Triton solution and 20 mg of fine powder with a median particle size below 10 μm. TXRF reliably determines sulfur in the suspension without acid digestion, showcasing its efficiency.

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4. Automated Mineral Liberation Analysis Techniques for Rare Earth Minerals

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Rare-earth elements (REEs) are found in various geological settings, and their analysis requires advanced techniques. Scanning electron microscopy (SEM) is employed for surface analysis, while inductively coupled plasma mass spectrometry (ICP-MS) determines REEs in ores. Non-destructive methods such as SEM with energy dispersive spectroscopy (EDS) and automated backscattered electron (BSE) image analysis, known as automated mineralogy, provide insights into particle-related aspects crucial in the beneficiation of REE ores.

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5. Automated On-Belt Sampling and Analysis of Ores

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Accurate chemical analysis is essential for optimizing mining operations. The automated on-belt sampling and analysis technique, using a cross-belt sampler, allows direct sample collection from a moving belt. The system is tailored to meet relevant sampling and preparation standards. Collected samples are crushed, and chemical analysis is performed in a fully automated process, seamlessly integrating results into the plant workflow and data management system.

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In conclusion, geologists are pivotal in implementing cutting-edge ore analysis technologies for revolutionizing mining operations. These technologies ensure accurate and rapid ore analysis, saving time, money, and effort while optimizing the mining process. As developments in imaging, analysis techniques, and artificial intelligence continue, a revolution in ore analysis is on the horizon.

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References and Further Reading:

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1.??????? Lane, C., (2022). How to Automate Sampling and Analysis of Ores and Mined Materials. [Online] Olympus. Available at: https://www.olympus-ims.com/en/insight/how-to-automate-sampling-and-analysis-of-ores-and-mined-materials/ (Accessed on 17 December 2023).

2.??????? Michaud, D., (2016). Wet Metal Assay Techniques. [Online] 911 Metallurgist. Available at: https://www.911metallurgist.com/blog/wet-metal-assay-techniques (Accessed on 16 December 2023).

3.??????? Pashkova, G., et al. (2020). Total-Reflection X-Ray Fluorescence Spectrometry as a Tool for the Direct Elemental Analysis of Ores: Application to Iron, Manganese, Ferromanganese, Nickel-Copper Sulfide Ores and Ferromanganese Nodules. Spectrochimica Acta Part B: Atomic Spectroscopy. doi.org/10.1016/j.sab.2020.105856.

4.??????? Schulz, B., et al. (2019). Automated SEM Mineral Liberation Analysis (MLA) with Generically Labelled EDX Spectra in the Mineral Processing of Rare Earth Element Ores. Minerals. doi.org/10.3390/min9090527.