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3D Model - Yukon Base Metal Project : Andrew and Darcy Deposit
Yukon Base Metal Drill Plan in Google Earth |
Andrew Zinc Project:
The Andrew Zinc Deposit was discovered in 1996 when a prospector followed up a stream geochemistry anomaly delineated during a 1989 government funded regional stream sampling programme. Noranda Inc. optioned the property in 2000 and intersected thick, high grade zinc mineralisation in the first drilling programme ever conducted on the project in 2001. A second drilling programme followed in 2002. Despite mineralisation remaining open in all directions Noranda relinquished its option in 2003.
Deposit Style
The Andrew Zinc Deposit fits the descriptive model for Ag-Pb-Zn vein system described by Beaudoin and Sangster (1992). Key features of deposits fitting this model include: (1) the occurrence of the veins in faults cutting monotonous sequences of metasedimentary rocks that were deposited in basins subsequently intruded by granitic to gabbroic rocks; (2) the veins occur late in the tectonic evolution of the basin, commonly associated with extensional collapse; (3) ore mineralogy dominated by galena and sphalerite with minor diverse sulfosalts, pyrite, chalcopyrite and tetrahedrite, gangue minerals commonly include siderite, quartz, dolomite or calcite; (4) minerals precipitated via mixing and boiling of three fluids, a magmatic or metamorphic derived component, an upper crust-equilibrated meteoric fluid and a meteoric fluid; (5) sulfur derived from local country rocks, carbon from deep-seated mantle sources and lead from either source. Analogous deposits include the Coeur d’Alene district, Idaho; Keno Hill, Yukon; Pribram, Czech Republic; and the Freiberg and Harz Mountains, Germany (Beaudoin and Sangster, 1992).
In addition to these features the host rocks occur in metallogenic provinces containing sediment hosted lead-zinc massive sulphide deposits (SEDEX) highlighting the high potential for the area surrounding the Yukon Base Metal Project to host an as yet undiscovered SEDEX deposit.
High grade zinc mineralisation at the Andrew Zinc Deposit
JORC Code Compliant Resource
A JORC Code compliant resource was calculated in May 2009 incorporating historical drilling and Overland Resources drilling results from 2007 and 2008. The resource estimate now stands at
7.2Mt at 6.2% Zn and 1.5% Pb (applying a 2% zinc cut-off).
The majority of the resource, over 70%, is in the measured and indicated category, as presented in Table 1.
TABLE 1. JORC Code compliant resource base for the Andrew Zinc Deposit.
| Classification |
Tonnes |
Zn (%) |
Pb (%) |
| Measured |
1,610,000 |
5.4 |
1.7 |
| Indicated |
4,690,000 |
6.2 |
1.6 |
| Inferred |
900,000 |
7.0 |
0.7 |
| TOTAL |
7,200,000 |
6.2 |
1.5 |
Metallurgy
Metallurgical test work on mineralised material collected from the Andrew Zinc Deposit highlights outstanding metal recovery rates of up to 96.2% for zinc and 98.5% for lead. Reported concentrate grades were 58.1% for zinc and 63.3% for lead. The metallurgical test results indicate that a conventional processing circuit will facilitate the production of metal concentrates of saleable grade from the Andrew Zinc Deposit.
TABLE 2. Metallurgical test results from the Andrew Zinc Deposit.
| Concentrate |
Recovery % |
Assay % |
| |
Lead |
Zinc |
Lead |
Zinc |
| Lead |
98.5 |
2.6 |
63.3 |
2.6 |
| Zinc |
0.8 |
96.1 |
0.4 |
58.0 |
Metallurgy is a key aspect of developing any new zinc mine. The development of numerous zinc deposits globally have been stalled due to difficult metallurgical properties preventing the cost effective liberation of the metal from the ore. The positive metallurgical test work results from the Andrew Zinc Deposit reduce the project risk and provide the Company with confidence that a low cost, low technological risk, processing circuit can be utilised in any future development.
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