Description
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Origin of Material
The material comes from a Geita gold deposit hosted within an Archean mesothermal orebody located in the Sukumaland Greenstones of the Geita Greenstone Belt. The deposit is largely hosted in a banded ironstone formation (BIF). Mineralisation is found where auriferous fluids, which are interpreted to have moved along shears often on BIF-diorite contacts, reacted with the BIF. Some lower-grade mineralisation can occur in the diorite as well (usually in association with BIF-hosted mineralisation).
Approximate Mineral and Chemical Composition
The mineralisation is associated with sulfidation fronts and replacements textures in ironstones and is mostly contained as disseminated sulphides in diorite. The major gangue mineral is magnetite with quartz, ankerite, and minor pyrrhotite and chalcopyrite. Approximately 20% of the gold is hosted in the diorite.
Recommended Concentrations and Limits
Certified Concentrations (at two Standard Deviations)
Analyte Method Certified Value (µ) Two standard deviations (2s) ± Unit
Au Pb Collection 25.00 1.4 g/t
Au FA_GRAV 24.58 2.8 g/t
Au PA 25.77 0.93 g/t
Ag 4A_MICP 557 22 ppm
Cu 2A_MICP 1751 201 ppm
Cu 4A_MICP 1779 87 ppm
C Combustion/LECO 2.53 0.14 %
S 4A_MICP 14.83 0.35 %
Al 4A_MICP 4.22 0.20 %
Be 4A_MICP 1 0.2 ppm
Ca 4A_MICP 2.41 0.23 %
Cd 4A_MICP 38 6 ppm
Ce 4A_MICP 58 8 ppm
Co 4A_MICP 281 28 ppm
Cr 4A_MICP 220 43 ppm
Cs 4A_MICP 2 0.2 ppm
Ga 4A_MICP 12 0.6 ppm
Ge 4A_MICP 0.1 0.03 ppm
Hf 4A_MICP 3 0.4 ppm
In 4A_MICP 0.4 0.04 ppm
K 4A_MICP 1.32 0.090 %
La 4A_MICP 27 5 ppm
Li 4A_MICP 16 3 ppm
Mg 4A_MICP 1.18 0.11 %
Mn 4A_MICP 1571 93 ppm
Mo 4A_MICP 15 3 ppm
Na 4A_MICP 8314 437 ppm
Nb 4A_MICP 5 1 ppm
Ni 2A_MICP 570 117 ppm
Ni 4A_MICP 595 73 ppm
P 4A_MICP 582 29 ppm
Pb 2A_MICP 2951 52 ppm
Pb 4A_MICP 2894 268 ppm
Rb 4A_MICP 49 2 ppm
Re 4A_MICP 0.01 0.002 ppm
Sb 4A_MICP 240 22 ppm
Sc 4A_MICP 13 1 ppm
Se 4A_MICP 9 3 ppm
Sn 4A_MICP 2 0.1 ppm
Sr 4A_MICP 166 11 ppm
Ta 4A_MICP 0.3 0.1 ppm
Te 4A_MICP 3 0.3 ppm
Th 4A_MICP 4 0.4 ppm
Tl 4A_MICP 0.7 0.07 ppm
U 4A_MICP 3 0.3 ppm
V 4A_MICP 116 15 ppm
Y 4A_MICP 16 3 ppm
Zn 2A_MICP 5138 153 ppm
Zn 4A_MICP 5002 420 ppm
Major Oxides
Certified Concentrations (at two Standard Deviations)
Analyte Method Certified Value (µ) Two standard deviations (2s) ± Unit
Al2O3 XRF 8.06 0.16 %
CaO XRF 3.48 0.068 %
Fe2O3 XRF 34.98 0.85 %
K2O XRF 1.59 0.044 %
MgO XRF 2.10 0.059 %
SiO2 XRF 28.45 0.46 %
TiO2 XRF 0.80 0.05 %
