43-101 2008 Technical Report On The La Fortuna Project, Durango ...

6.0 MINERALIZATION
Gold mineralization on the Property is hosted by thinly-bedded volcaniclastic rocks of the Lower Volcanic
Series and adjacent dacitic sills or dikes. The mineralized zones have locally been oxidized to depths
greater than 200 m below surface but an average depth is more in the order of 150 m.
Mineralization occurs in a series of northwest-trending lenses up to 150 m in length and 40 m in width.
This northwest trend probably reflects individual mineralized volcaniclastic units. While the trend of the
individual mineralized bodies is to the northwest, the overall trend of ALL the mineralized bodies is to the
northeast, suggesting a possible northeast-trending structural control such as a structure through which the
mineralizing fluids gained access to the permissive host rocks.
Mineralization in thinly-bedded volcaniclastic rocks is disseminated and occurs with earthy red hematite
(Plate 2) or in narrow fractures with earthy red hematite (Plate 2). Quartz is rare although quartz veinlets
are present locally.
Plate 2. Mineralized thinly-bedded volcaniclastic rocks.
Due to extensive oxidation, primary hydrothermal alteration is difficult to characterize. Silicification is
rare, although some of the chalcedonic silica may have formed by replacement of volcaniclastic units.
Argillic alteration is widespread but may be related to supergene processes. Strong potassic alteration in
the form of biotite and potassium feldspar in fractures with some secondary copper minerals within
intermediate intrusive rocks may suggest a porphyry copper environment at depth (Arturo Guerrerro,
personal communication).
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