Nandi
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Property Type
Porphyry Copper Project
Size
5,000 ha
Status
Available for Partnership
Exploration Stage
Lithological and alteration mapping,
Geochemical stream sediment, soil and rock chip samplingLocation
- Located in the Paleocene porphyry Cu belt in northern Chile
- Easy road access along the asphalt highway from the port city of Antofagasta
- 30 km northwest of BHP’s Escondida Cu mine and 63 km southeast of Glencore’s Lomas Bayas Cu mine
The 100% owned Nandi Copper Project is located in the Paleocene porphyry Cu belt in northern Chile. The project was staked and 100% owned by Mirasol through its project generation program and comprises approximately 5,000 ha of exploration claims. With its first-pass reconnaissance and exploration programs completed, multiple targets have been delineated for follow up.
Geologically, Nandi is favorably situated in the area of intersection between the continental-scale north-south trending Domeyko Fault System and the northwest trending Archibarca Lineament, a regional structural framework that, for example, controlled the emplacement of the giant Escondida porphyry Cu deposit cluster. The project also benefits from easy access along the asphalt highway from the port city of Antofagasta to the Escondida mine, lying at a relatively low altitude of 1,800m above sea level.
To date, Mirasol has completed first-pass reconnaissance and exploration programs, including:
- Reconnaissance scale lithological and alteration mapping supported by spectral mineralogy analyses of rock samples;
- Geochemical stream sediment and rock chip sampling;
- Focused geochemical channel sampling from nine historical trenches; and
- Soil geochemical sampling on a 100 x 200m grid at the Border Zone target.
The results of these initial surveys have delineated multiple exploration targets for detailed follow up.
The Border Zone target, located in the northeast area of the Nandi project, has the potential to host porphyry Au/Cu style mineralization. Cretaceous andesites and volcanic breccias host a series of multiple phases of intrusive and hydrothermal events, which notably include a quartz porphyritic rhyodacite intrusive body that is cut by black banded quartz veins (BBV) and a phreatic breccia with banded quartz veined clasts. BBV veining is typically found in porphyry Au deposits of the Maricunga Belt such as the Marte deposit (Indicated Resources: 33.47 Mt at 1.58 g/t Au1). Anomalous Au includes assay values ranging from 0.1 to 2.6 g/t Au in rock chip samples (out of 65 samples, 8 samples returned over 0.1 g/t Au and 2 samples over 1 g/t Au), as well as 7 samples with values of 15 to 40 ppb Au from a soil grid completed over the Border Zone target. In addition, anomalous Cu values ranging from 100 to 4,850 ppm in rock chip samples were recovered in this zone (out of 65 samples, 7 samples returned above 200 ppm Cu).
The Central Zone target is located some 4 km west-southwest from the Border Zone target in the center of the tenure. It is characterized at surface by thin horizons of Pb-Zn stratiform mineralization with traces of secondary Cu oxides hosted by Jurassic silty dolomites. This mineralization may possibly be related to the intrusion of dykes of Paleocene quartz diorite and rhyolite quartz porphyry exposed in the historical trenching. Disseminated and also northwest fracture-controlled goethite and jarosite (1-3% by volume) could have formed from pyritic mineralization peripheral to a larger intrusive either at depth directly below the Central Zone, or under the gravel cover of the Pampa Zone directly to the north. In regard to the latter, there is a discrete, sizable magnetic low some 2 km in diameter, which could present a porphyry Cu target.
Initial exploration results have been encouraging and highlight the potential for porphyry Cu mineralization which merits follow up field work including geophysical surveys, to define targets for drill testing.
1Teck Cominco Limited – 2006 Annual Information Form
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