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Regolith Enrichment of the Wonmunna Marra Mamba Iron Ore Deposits of the Hamersley
Region, Western Australia
Angela MarshallSupervisor Dr Solomon Buckman
University of Wollongong
Iron OreMount Whaleback
Mount Tom Price
Aim
to describe the nature of the iron mineralisation at Wonmunna and
determine the processes responsible for Fe-enrichment
WONMUNNAHamersley Province, Pilbara
Wonmunna
Banded Iron Formation (BIF)
SILICA
Fe
FeSILICA
SILICA
Ore Types
Unenriched BIF
Martite-goethite ore
Microplaty-hematite ore
Enrichment ProcessesHypogene Model1. warm, reduced fluids leach silica2. Oxidisation ( hot meteoric oxidising fluids)3. Microplaty hematite formed in carbonate matrix4. Late stage supergene leaching
Taylor et al., (2001)
Supergene – Metamorphic Model
1. Supergene processes for martite-goethite ore2. Burial metamorphism upgrades this to
microplaty-hematite ore
Morris (1985)
Regolith ProcessesRamanaidou (2009)
Field work and mapping
Petrography
10 x, plane polarized light 10 x, crossed polarized light
Reflected light microscopy
Distribution of minerals downhole, NMM deposit Hole 150
0% 20% 40% 60% 80% 100%
0-2
2-4
4-6
6-8
8-10
10-12
12-14
14-16
16-18
18-20
20-22
22-24
24-26
26-28
28-30
30-32
32-34
34-36
36-38
38-40
40-42
42-44
44-46
46-48
48-50
50-52
52-54
54-56
56-58
58-60
60-62
62-64
64-66
66-68
68-70
70-72
Dep
th (m
)
Composition %
HematiteGoethiteMagnetiteQuartzKaolinite
MineralogyXRD
Conclusion• Relationship with the current surface and
regolith development.
• Microplaty hematite in the Marra Mamba Iron Formation at Wonmunna
• Regolith enrichment model for Wonmunna: oxidation, leaching, goethitisation dehydration of goethite mpl-H
• Implications for exploration models
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