1. Representative, high-spatial resolution geochemistry from diamond drill fines (powders): An example from Brukunga, Adelaide, South Australia.
- Author
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Uvarova, Yulia A., Gazley, Michael F., Cleverley, James S., Baensch, Aaron, Lawie, David, and leGras, Monica
- Subjects
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ROCK-drills , *GEOCHEMISTRY , *HYDROTHERMAL alteration , *X-ray diffraction , *ORE sampling & estimation - Abstract
The analysis of drill powders (drill fines) extracted from fluid that is returned during drilling can provide a sampling media that records cm-scale changes in the geochemistry of the rock being drilled through. In addition to being an ideal sample media (~ 78% of particles are < 38 μm; cf. conventionally pulverised samples where ~ 42% of particles are < 38 μm) that is ready for analysis once dried, diamond drill fines may produce a larger sample per meter drilled than recovered by the core itself, and thus be a better representation of the rock that has been drilled through. For an HQ hole size (for rocks with specific gravity = 3100 kg/m 3 ), the mass of drill fines produced in 1 m of drilling is 12.5 kg, whereas, the mass of the 1 m in length of core for the same interval is 9.7 kg. In this contribution we compare high-spatial resolution geochemistry collected by portable X-ray fluorescence (pXRF) and mineralogy collected by portable X-ray diffraction (pXRD) from 12 m of diamond drill core to the corresponding interval of drill fines to highlight the depth fidelity (at the cm-scale) that this sample source may record. We also demonstrate that the drill fines that were previously discarded show high potential to act as a representative sample media of the lithology intersected by the drill hole and can be successfully used for analysis in real time. The integrated pXRF-pXRD data can be used to constrain lithologies and contacts between various units, hydrothermal alteration and ore types. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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