Latin Resources Limited (ASX: LRS): Ilo Norte Copper-Gold Project: Part II
The geology of Ilo Norte comprises a sequence of volcanic and sedimentary rocks, up to 600 metres thick, that dips moderately to the north-northeasteast. The rocks are variably altered, with the central 300 metres of the sequence being the most altered, as shown in the figure below. This is the target zone for the forthcoming drill program.
The alteration extends for a strike length of at least 10 kilometres, all on ground held by Latin Resources. This alteration is important for several reasons:
- Many mineral deposits are surrounded by a halo of altered rocks that is a much larger exploration target than the deposit alone.
- Variations in alteration can be used as vectors for the location of a mineral deposit
- Large alteration zones can indicate large mineral deposits
Notwithstanding the above, it is important to note that while most mineral deposits are surrounded by alteration, there are many altered rocks that do not host mineral deposits. However, at Ilo Norte the alteration is accompanied by iron, copper and gold.
Ilo Norte – Cross section showing drill target and proposed drill holes
The target zone outcrops at surface but has been extensively leached, or weathered. This means that any sulphides have long gone. However, although the sulphides have been leached, they have left behind evidence of their presence. Shapes (“boxworks”) characteristic of chalcopyrite (the main ore of copper) have been recognised within the target zone at surface.
Eight drill holes completed in 2011 are downslope of the target zone, but nonetheless returned good results. The best results were 36 metres at 0.29% copper and 0.09g/t gold; and 21 metres at 0.25% copper and 0.09g/t gold.
The “IP Chargeability Anomaly” in this setting will almost certainly be caused by sulphides (pyrite and chalcopyrite) and/or magnetite. The forthcoming drill program will target this large anomaly at a depth of around 400 metres.
This is a superb drill target. It is located within a very large alteration system that is comparable with alteration zones around giant iron-copper-gold deposits in Peru and northern Chile. Drilling is imminent, watch this space.
18 March 2013
Disclosure: Market Capital holds securities in Latin Resources Ltd as at the date of publication of this article.