Accuracy of expanded vermiculite ore spectral source determinations.

Accuracy of expanded vermiculite ore spectral source determinations.

Detailed Description

Table 7.  Accuracy of expanded vermiculite ore spectral source determinations and impurity detections. 

Notes: Samples evaluated for impurities using the Modified Cincinnati Method (MCM) with separates examined by Scanning Electron Microscope – Energy-Dispersive X-Ray Spectroscopy (SEM-EDS) for the presence of amphibole, talc, and/or serpentine, and using the spectral 1.40/1.42-µm band depth ratio.  

a Details of MCM, electron probe microanalysis (EPMA), spectroscopy, XRD, and SEM-EDS analyses for expanded vermiculite ore samples can be found in Swayze et al. (2018).

b The expanded Enoree GDS651 sample has no detectable 1.38-µm absorption, so its symbol plots on the zero 1.38/2.32-µm band-depth-ratio line as do the Louisa sample symbols.  

c Only three of the expanded Enoree samples, one expanded Palabora sample, and one expanded “Mixtures” sample had sufficient volume for using the MCM for separating amphibole bundles.  

d The GDS629 sample was misidentified as an expanded Libby ore when it was actually a mixture of expanded Palabora and Enoree ores.  The 2.24-µm band position test (Fig. 21) reduces these types of false positive identifications (see text for details).  

e Three EPMA spot analysis values fall in the Enoree provenance field suggesting that the GDS327 sample is actually a mixture of expanded Palabora and Enoree ores and not just an expanded Palabora ore as indicated by spectroscopy.

f The expanded Jiangsu sample had insufficient volume for using the MCM. 

Details

Image Dimensions: 1000 x 445

Date Taken:

Location Taken: US