Specifications
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CRM State:
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Matrix:
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Mineralisation:
OREAS 909 was prepared from oxide ore sourced from the Sepon Copper–Gold Mine, Savannakhet Province, Lao P.D.R. The material is representative of oxidised copper mineralisation typical of the Sepon district.
Copper occurs predominantly as finely disseminated phases within a gangue-dominated matrix. Mineralisation comprises minor residual sulphide minerals (including pyrite and chalcopyrite as identified by XRD) together with secondary and/or non-crystalline copper-bearing phases that are not readily detectable by XRD. The gangue mineral assemblage is dominated by quartz, dolomite, clay minerals (muscovite/illite and kaolinite), and minor feldspar and apatite, consistent with a weathered and oxidised ore system.
Ten commercial analytical laboratories participated in the program to certify the elements reported below using the following methods:
To confirm homogeneity, gold by instrumental neutron activation analysis (INAA) was undertaken on 20 x 85mg. This format enabled a nested ANOVA treatment of the INAA results to compare within- and between-unit variances, providing a statistical measure of batch homogeneity.
| Analyte | Certified Value | 1SD | Expanded Uncertainty Low | Expanded Uncertainty High | Method |
|---|---|---|---|---|---|
| Cu, Copper (ppm) | 8472 | 99 | 8338 | 8605 | 4-Acid Digestion |
| Au, Gold (ppb) | 80 | 3.6 | 75 | 84 | Pb Fire Assay |
| Ag, Silver (ppm) | 6.25 | 0.287 | 5.62 | 6.88 | 4-Acid Digestion |
| S, Sulphur (wt.%) | 0.694 | 0.011 | 0.674 | 0.715 | 4-Acid Digestion |
| C, Carbon (wt.%) | 2.92 | 0.037 | 2.86 | 2.98 | Infrared Combustion |