The greatest challenge in the precious metal mining industry (gold, silver, platinum group metals) is the production of consistently high-grade concentrates at maximum recovery rates. Grade of a concentrate is directly related to the mineralized block, gold distribution and diluents such as other sulphides, graphite, clays or organic matter and process conditions. 

Malvern Panalytical delivers analytical solutions to monitor geological, mineralogical and metallurgical parameters to optimize grade block definition, mine planning as well as the profitability of gold, silver and PGM mining operations. Our experts develop tailored designs together with exploration geologists, mine planners, process engineers, quality- and laboratory managers as well as for geometallurgists and plant managers.

Gold, Silver & PGM Exploration

Mineral exploration of gold, silver and PGM metal ores becomes more challenging every year. Mines increasingly facing lower ore grades and complex mineralogy, forcing mills and concentrators to process more material. Mine planning, separation and concentration are directly related to mineralogy, metallurgy and variability of the ore body. 

Malvern Panalytical offers portable mineralogical and analyzers that enable exploration geologists to safely obtain immediate information in the field or mine, to identify precious metal bearing mineralogical domains and predict optimal extraction and processing conditions. 

Our solutions based on Near InfraRed (NIR) spectroscopy deliver - with a push of a button - mineralogical results and can additionally track geochemical conditions using the Al-OH scalar or the Illite Spectral Maturity (ISM) scalar, an indicator of thermal maturity of a deposit. Our portable X-ray fluorescence spectrometers operating under safe conditions and allow to detect gold concentrations on loose powders down to less than 1.5ppm within 10 min.

Grade control & ore sorting

Mineral processing of gold, silver and PGM ores requires a constant quality of ore feed to the concentrator. Real-time elemental monitoring of ore passing on a conveyor belt enables ore sorting of precious metal ores based on proxy minerals and allows blending of different ore grades to a constant feed. If a mine can effectively exclude low quality ore feed, it can effectively increase the capacity of the concentrator, regardless the process. 

Many old gold tailing facilities have still impressive residual mineral values and get in the focus of mining companies for reprocessing. Such tailing damns provide opportunities to help in environmental reclamation, while at the same time, generate additional revenue. Malvern Panalytical offers expertise and analysis solutions to monitor the composition of such tailings to ensure efficient reprocessing.

Separation & Refining

By identifying mineralogical domains and monitoring the mineral composition at each step of the process, ore streams can be modified depending on the requirements during separation and concentration of precious metals. Based on the mineralogy composition the optimal amounts and mixtures of reactants or reagents can be applied to increase recovery rates and reduce costs for energy and consumables. 

X-ray diffraction is an easy, fast and reliable tool to quantify the mineral content even of complex ores. Our industrial diffractometers are designed to work in rough industrial environments. The equipment can be automated and tailored to the specific needs of precious metal ore processing. Besides mineral quantification, we provide statistical tools to direct predict process parameter and ensure short feedback loops to plant operation. 

Preg-robbing 

The absorption of precious metals by carbonaceous components in the ore, “Preg-robbing”, is a well-known challenge during flotation and leaching of precious metal ores. Our analytical solutions enable monitoring of the mineral and elemental composition as well as zeta potential. This makes immediate counteractions possible to prevent preg-robbing and increase gold, silver and PGM recoveries.

Analysis of Au on activated carbon 

A common activity of precious metal ore processing is the analysis of the Au concentrations on activated carbon. This is a critical measure on the efficiency of the carbon in pulp (CIP) and carbon in leach (CIL) processes. 

By measuring the gold in the stripping solution, operators can quickly and easily determine when the solution will be barren of gold, significantly improving the plant’s efficiency. Our benchtop X-ray fluorescence solutions offer a simple and low cost at-line analytical technique for monitoring the elemental composition of such solutions. Non-technical operators obtain results within minutes without the need for special sample preparation, sample conditioning or technical knowledge.

Optimizing charge make-up, slag and ingot production in gold refineries 

In order to achieve the most efficient and cost-effective refining and smelting process, the charge make-up for refineries needs to be perfected for each gold deposit, requiring detailed knowledge of each deposit’s mineral composition. One important component is iron bound in the minerals magnetite (Fe3O4) and hematite (Fe2O3), which require different amounts of reactant for compensation. Where elemental analysis previously only revealed the concentration of the total iron content, X-ray diffraction can now easily determine the amounts of both phases. With this knowledge furnace conditions can be optimized, resulting in huge energy savings. 

Continuous slag analysis using our XRD solutions, considerably improves the effectiveness of the melt by monitoring crystalline phases and amorphous content. The identifying silicon carbide and graphite in surface markings on the gold cast bars allows traceability back to their sources in the crucible and the casting moulds and enables optimal control of the ingot production process.

Mining waste management

All gold recovery processes generate waste material that must be disposed in the environment. In order to avoid legal problems and ensure sustainable mining, rejects of precious metal mining must be carefully monitored. 

Our dedicated analytical solutions secure safe waste management according to international norms and regulations and avoid penalties by: 

  • Elemental analysis of soil and waste water
  • Characterization of swelling and non-swelling clays
  • Particle size and shape characterization of tailings
  • Measurement of zeta potential of mine waste water and other rejects
Expert solutions in precious metal mining and processing. Contact us to discuss your challenges.
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