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Scientific Communications: Evaluation of Inter-Instrument Variations among Short Wavelength Infrared (SWIR) Devices
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posted on 2023-05-17, 16:10 authored by Chang, Zhaoshan, Yang, ZIn this study we investigate the inter-instrument variation of the alunite 1,480-nm OH (overall range ~1,475- 1,498 nm) and the white mica Al-OH (overall range ~2,186-2,225 nm) spectral absorption features by measuring the same sets of samples using two devices of each of the three major types of portable SWIR instruments: portable infrared mineral analyzer (PIMA), TerraSpec, and portable near-infrared spectrometer (PNIRS). All instruments have good short-term reproducibility. The ARC Centre of Excellence in Ore Deposits (CODES) PIMA was assessed for long-term reproducibility and it was found to be stable, with 0- to 1-nm variations over at least seven years. There are differences in the results measured by different instruments, even of the same type. The PIMA instrument from the Economic Geology Research Unit generates alunite results 1 to 2 nm lower than those of the CODES PIMA. The two TerraSpec instruments used in this study produced results very similar to each other, mostly with 0- to 1-nm differences in alunite 1,480-nm spectral absorption measurements, but the results are 1 to 3 nm lower than those of the CODES PIMA. The two PNIRS devices generated results that differed from each other by 1 to 4 nm, mostly with 2- to 3-nm differences in alunite measurements. Compared with the PIMA results, one PNIRS dataset is very similar, with 0- to 1-nm differences, whereas the other PNIRS dataset is 0 to 5 nm off, mostly with 3-nm differences, in alunite measurements. The white mica Al-OH spectral absorption feature wavelength measurements are more similar among the instruments, with the maximum difference being 2 nm. Despite the differences in absolute values, the ranking of the samples in those datasets for the two tested parameters is largely the same, which indicates that all the instruments will produce datasets showing the same trends. The implication is that one project should use the same instrument for all the measurements. If another instrument has to be used, or the original instrument is repaired or tuned, it is suggested that a set of samples covering most of the variation range should be measured with both instruments to evaluate the inter-instrument variation and to establish a correction formula to keep consistency in the database. © 2012 by Economic Geology, Inc.
Funding
Australian Research Council
AMIRA International Ltd
ARC C of E Industry Partner $ to be allocated
Anglo American Exploration Philippines Inc
AngloGold Ashanti Australia Limited
Australian National University
BHP Billiton Ltd
Barrick (Australia Pacific) PTY Limited
CSIRO Earth Science & Resource Engineering
Mineral Resources Tasmania
Minerals Council of Australia
Newcrest Mining Limited
Newmont Australia Ltd
Oz Minerals Australia Limited
Rio Tinto Exploration
St Barbara Limited
Teck Cominco Limited
University of Melbourne
University of Queensland
Zinifex Australia Ltd
History
Publication title
Economic GeologyVolume
107Issue
7Pagination
1479-1488ISSN
0361-0128Department/School
School of Natural SciencesPublisher
Society of Economic Geologists, Inc.Place of publication
7811 Shaffer Pky, Littleton, CO 80127 USARights statement
Copyright 2012 Society of Economic Geologists, Inc.Repository Status
- Restricted
Socio-economic Objectives
Other mineral resources (excl. energy resources) not elsewhere classifiedUsage metrics
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