Onix contains three gold targets spread over a 2 km2 area associated with a south-west trending shear zone located 26 km due south-west from the Aurizona Mine (Figures 1 and 2). Geochemical and geophysical data combined with geological mapping indicate that this target holds potential to host high-grade gold mineralization.
Figure 1. Location of the Onix target, Luna Greenfields project overlain on 1VD magnetic grid (CPRM, 2008).
Figure 2. Location of the Onix target within the Onix Shear Zone (OXSZ). Overlain on total field magnetic grid.
The Onix target was an active garimpo (artisanal mine) in the 1980′s where quartz veins hosted by tonalites and weathered basic volcanics were mined along diverse elongate structures. Outcrop is scarce and limited to garimpo pits. Onix is located 6 km due west south-west from the Areal target and several artisanal workings occur between both these targets. Gold is hosted in pyrite-bearing quartz veins with occasional tourmaline. Onix North is a narrow structure with pits extending along a 300 m strike length. The presence of vertical shafts and collapsed galleries coupled with elevated gold grades in quartz veins and tailings suggests potential for high-grade mineralized zones along the structure. Rock grab sampling from around the pits and pit walls returned several high-grade samples including 9.12 grams of gold per tonne (g/t Au), 5.06 g/t Au and 3.46 g/t Au. Grab sampling of tailings dumps also returned encouraging grades including best values of 4.24 g/t Au, 2.31 g/t Au and 2.16 g/t Au.
Onix South is located 0.5 km south-east from Onix North and consists of two north-east trending pits and several vertical shafts. Rock grab sampling around the pits returned best values of 1.37 g/t Au and 0.51 g/t Au. Grab sampling of tailings dumps returned best values of 2.63 g/t Au, 1.80 g/t Au and 1.52 g/t Au. Onix North and Onix South are separated by a strong magnetic low anomaly representing the Onix structures.
Luna’s field teams have also discovered a new sub-cropping mineralized structure located between the main Onix workings described above. Samples of quartz, some of which contain visible gold, assayed 41.00 g/t Au, 27.40 g/t Au and 4.49 g/t Au. 42 out of 46 rock and tailings grab samples collected across the entire Onix target assayed greater than 0.10 g/t Au. The adjacent table contains a summary of Luna’s reconnaissance rock and tailings sampling program at Onix.