2012 – COM 2012, Niagara Falls Canada


The QEMSCAN system is the third generation of automated mineral analysis systems that began
with the QEM*SEM at CSIRO 30 years ago (Butcher et al. 2000). It is now a successful commercial
instrument with 39 instruments in operation around the world. Back Scattered Electrons (BSE) and Energy
Dispersive (EDS) X-Ray spectra are used to create digital mineral images with mineral identification
occurring online. Low-count EDS spectra are used preferentially to BSE brightness, allowing minerals to
be accurately identified by chemical composition. Individual minerals or groups of similar compositions
are identified by comparison to a comprehensive mineral database incorporated into the QEMSCAN
software. Optical mineralogy and Scanning Electron Microscopy is a metallurgists’ tool for determining
the ore process mineralogy and delivering a better flowsheet. These techniques have limitations, provide
limited information and sometimes fail to provide representative information. In contrast, QEMSCAN
provides information on the nature and occurrence of all mineral species present plus the liberation
characteristics, looking at thousands of particles in the sample presented. Some of the data presented
• Particle and grain sizes
• Dominant mineral species
• Particle shape
• Calculated metal content
• Density
• Deportment of elements of interest between the mineral phases
• Quantitative mineralogy
• Mineral associations, locking and liberation
• Textural relationships (particle images)
It can also be used on concentrates, polished sections or drill core. This is a significant improvement in
ore characterisation providing lithology, mineralogy, liberation, ore grade and porosity from a sample.
Theoretical grade-recovery curves can be created to be mineralogically limited from QEMSCAN analysis
which, when compared with metallurgical results, are valuable in evaluating whether liberation or chemical
selectivity is driving flotation performance. A number of case study examples are given where the
QEMSCAN had a significant bearing on future project development at an early stage of exploration and
mine development.

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