Mineral Products
Above: Analysis of an abrasive feedstock not only provides information on the size, shape and association of the target mineral (garnet; red) but also the abundance and distribution of deleterious minerals (e.g. quartz; beige). In this case, most of the quartz occurs as free sand grains which can be removed during processing. However, micron-sized inclusions also occur within some of the garnet grains and may become problematic as the abrasive fragments during use.
The primary focus of Automated Mineralogy development was in the mineral processing and metallurgical application areas where both the mineralogy and the mode of occurrence of the phases of interest are of importance. Data such as liberation, locking, association, and mineral size are all key parameters for the optimization of the various processing circuits in the plant.
For instance, amongst other things, liberation is key to understanding grinding performance; poor liberation often indicates insufficient grinding and, conversely, minerals that are liberated but reduced in size, can indicate inefficiencies such as over-grinding. Characterization of feeds, products, and wastes is therefore critical in maximizing efficiency and associated cost management.
Indeed, even before a resource enters the plant, ore characterization studies provide information such as mineral size, association, and texture which give critical insights into the processability of each ore zone and are powerful tools in the prediction plant performance.
Bright Phase Searches
Precious metals such as gold, silver, and platinum group elements typically occur as sparse, extremely small (often micron-sized), finely disseminated grains. Scanning samples to find these phases is often prohibitively time consuming.
Fortunately, heavy elements such as these show as very bright specks under the electron beam. Hence, scans can be optimized to only target particles that contain these bright phases. Other particles are ignored thereby substantially speeding up the analysis.
Data outputs include attributes such as size, shape, composition, elemental deportment, as well as association, locking, and liberation; all key factors for understanding the ore and improving recovery.
Heap Leach
Heap leach operations have many similarities to oil and gas reservoirs; effective fluid flow is vital for production, mobilization of clays can be problematic, and alteration, dissolution, or precipitation of minerals can be deleterious.
Analysis of the feedstock can help predict if clay and silt mobilization, mineral precipitation or other factors are likely to be an issue. Similarly, even in the low grade ores typically processed using heap leach, automated mineralogical analysis can provide insights into recovery performance. For instance, information such as locking, liberation, and association can be derived for vector minerals.
Left: Automated mineralogy image of heap leach feed. Particles are porous allowing for penetration of the leach solution but clays (green) are potentially mobile.