Quantitative Evaluation Of Minerals By Scanning Electron Microscopy (QEMSCAN™)
The QEMSCAN™ is a fast chemical data collection system which uses a combination of backscattered electron SEM images and EDS analysis to create an image of a sample based on chemical composition.
These images can then be processed off-line to provide modal abundance, grain size, mode of occurrence and liberation information. Because the elemental proportions of each identified mineral are stored in the QEMSCAN™’s database, a “chemical analysis” can also be calculated. New mineral information can be entered into the database as required.
The detailed analysis establishes not only the percentage of each mineral in the sample, but also the proportions of elements of interest contained in each mineral phase, if it is in an easily accessible form, and how much is recoverable.
The information can be used to guide exploration, assess ore body delineation, develop processing routes and improve plant operations.
The QEMSCAN™ has three basic modes of operation:
- Point Scan
- Line Scan
- Area Scan
With all three modes of operation, a BSE scan of the field of view is performed to locate mineral particles for analysis before any EDS analyses are carried out. This ensures that time is not wasted analysing the epoxy mounting medium. A BSE threshold or window can also be set to include only minerals of interest. In this way, the QEMSCAN™ may also be used to search for low grade specific mineral phases in a sample. (eg. gold and PGM particles).