Re: UXA - Uranium Exploration Australia
16.5 Drill Bit Contamination and Analysis
Although anomalous silver mineralization occurs on the property, erratically high and irregularly occurring silver assays indicated a possible silver contamination particularly in zones of strong silicification, silica sand and incompetent rock. Drill bits were often broken and chipped through these intervals and returned with the core. It was postulated that pieces of milled drill bits inadvertently were included in the samples enhancing the silver values. As such, an effort was made to distinguish between ‘natural’ silver mineralization and silver contamination from drill bit material.
To that end, 30 gram samples of drill bit and adhered core material were gathered by hand magnet and sent for geochemical analysis. Samples were crushed and prepared by ALS-Chemex laboratories in Izmir, Turkey and the pulps were shipped to ALS Chemex in North Vancouver, BC for analysis. Samples were analyzed by fire assay and by ICP-AES with Aqua Regia Digestion. The drill bit samples displayed maximum enrichment of Ag (x8), Co (x800), Cr (x50), Cu (x50), Fe (x12), Mn (x15), Mo (x50), Ni (x30), V (x3), W (x20) and Zn (x30). Based on
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these findings criteria to distinguish the naturally occurring silver from that of the drill bits was determined.
Naturally occurring silver mineralization is characterized by:
Wide intervals of silver mineralization, concomitant with gold mineralization.
Good depth correlation of mineralization between drill holes.
Competent core.
Limited to no drill bit material.
Concomitant enrichment of silver with Sb, Au, Bi, Hg, and some Mo.
Contaminated core displays some or all of the following characteristics:
Isolated, highly-enriched samples within otherwise barren siliceous core.
Poor correlation between drill holes.
Severe reduction of core competency, commonly to silica sand.
Readily apparent drill bit material.
Concomitant enrichment of silver and tungsten (commonly with Co, Cr, Cu, Fe, Mn, Ni and V).
crayfish said:
16.5 Drill Bit Contamination and Analysis
Although anomalous silver mineralization occurs on the property, erratically high and irregularly occurring silver assays indicated a possible silver contamination particularly in zones of strong silicification, silica sand and incompetent rock. Drill bits were often broken and chipped through these intervals and returned with the core. It was postulated that pieces of milled drill bits inadvertently were included in the samples enhancing the silver values. As such, an effort was made to distinguish between ‘natural’ silver mineralization and silver contamination from drill bit material.
To that end, 30 gram samples of drill bit and adhered core material were gathered by hand magnet and sent for geochemical analysis. Samples were crushed and prepared by ALS-Chemex laboratories in Izmir, Turkey and the pulps were shipped to ALS Chemex in North Vancouver, BC for analysis. Samples were analyzed by fire assay and by ICP-AES with Aqua Regia Digestion. The drill bit samples displayed maximum enrichment of Ag (x8), Co (x800), Cr (x50), Cu (x50), Fe (x12), Mn (x15), Mo (x50), Ni (x30), V (x3), W (x20) and Zn (x30). Based on
37
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these findings criteria to distinguish the naturally occurring silver from that of the drill bits was determined.
Naturally occurring silver mineralization is characterized by:
Wide intervals of silver mineralization, concomitant with gold mineralization.
Good depth correlation of mineralization between drill holes.
Competent core.
Limited to no drill bit material.
Concomitant enrichment of silver with Sb, Au, Bi, Hg, and some Mo.
Contaminated core displays some or all of the following characteristics:
Isolated, highly-enriched samples within otherwise barren siliceous core.
Poor correlation between drill holes.
Severe reduction of core competency, commonly to silica sand.
Readily apparent drill bit material.
Concomitant enrichment of silver and tungsten (commonly with Co, Cr, Cu, Fe, Mn, Ni and V).
