HEBERTO STYLE gold mineralization was intercepted in several holes from ten meters to tens of meters, that is sheared, silicified, pyritized, biotitized and potassic feldspar altered mineralized intercepts.
Initial diamond drilling results on the HEBERTO showing from first drill hole completed yielded 4.79 g/t Au over 8.65m (from 18 to 26.65 m depth) within a larger envelope grading 2.13 g/t Au over 22.90 m (true width). Mineralization consists in 1-5% mm quartz (carbonate) and/or 5-30% biotite (magnetite) stringers associated with traces to 3% pyrite and traces of chalcopyrite, hosted within a plurimetric north-south striking sheared potassic altered contact zone between a tonalite and a diorite.
Previous channel sampling on newly outlined mineralized structure returned up to 5.18 g/t gold over 5 m. Two 2014 grab samples from quartz veinlets bearing quartz-diorite intrusives returned 8.06 and 7.89 g/t gold at southern and eastern ends of stripping.
MAG VS DDH
ROBINO BECCIA FACIES
The AU33West property is located within the Lower Eastmain greenstone-belt wrapped around the Mistumis tonalite-granodiorite-diorite pluton of the Archean LaGrande Sub-province. The AU33West project hosts a regional east-west striking deep structure (Chain Lake Break) along which numerous significant gold occurrences such as Eastmain Clearwater and Virginia Mustang-Wabamisk gold systems are present. Along this favourable break, an area with complex cross-cutting NW-NNW-NS subsidiary structures was targeted and new gold showings were uncovered.
About 350 km NE of Matagami, near the James Bay EM-1 power dam, the AU33West project covers 200 sq. km. Access to the project is by Hydro-Quebec gravel road linking Nemaska/Eastmain-1/LaSarcelle.
AU33W MAG VS CHAIN LAKE
Dios 2009-2010 till sampling outlined a 15 km x 3-7 km well-structured gold anomalous dispersal train. This gold dispersal train is N240-250 striking, same as the area reported glacial striaes.
Dios compilation of all available till data for Lower Eastmain highlights the importance of this gold train.
AU33W TILL MAP
In 2010, a 3 day reconnaissance was carried out at the head of Eastmain-1 till gold train. From 40 representative samples from glacial (mineralized tonalite & basalt) floats, three 40-75 cm size tonalite boulders with 2-5% disseminated pyrite assayed 0.84 g/t Au, 1.5 g/t Ag ; 2.3 g/t Au, 1.6 g/t Ag ; and 2.3 g/t Au, 6.6 g/t Ag . Thin sections on auriferous floats confirmed potassic (biotite, microcline) alterations.
From July 2011 till November 2013, Osisko had the option to acquire a 51% undivided interest in the property and incurred some 1.4 M$ in exploration expenditures.
In 2011, two prospecting campaign carried out on the AU33 WEST property targeted the felsic (tonalite-granodiorite) igneous complex, diorites and volcanic belts found up-ice of gold-bearing till dispersal trains and boulders defined by DIOS’ earlier work. Outcropping auriferous mineralization comprises 1-2% pyrite as disseminations and fracture fillings, locally with minor chalcopyrite and malachite, and is associated with potassic alteration. Gold values are associated with silver grades and generally copper as well, suggesting a magmatic-hydrothermal deposit. Osisko completed geological mapping-prospecting, soil geochemistry (2 grids; b-horizon & humus). Dios and Osisko discovered several gold showings in outcrops ( between 0.535 and 3.79 g/t gold) in tonalitic rocks.
During the 2012 summer, a field program outlined five new gold showings in the tonalte-granodiorite complex. In the fall, further work revealed outcropping gold showings, with 34 of mineralized outcrops centered in an 18-km2 area. All showings yielded values above 100 ppb gold (0.1 g/t Au), and seven between 1.58 g/t and 23.6 g/t Au. In the 2012 Fall, ten trenches were dug to test soil geochemical anomalies or to extend known showings. Some targets were not fully tested due to overburden and accidental nature of the ground. Heberto showing (trench T7), a first priority target returned 5.0 g/t gold (grams per tonne) over 5.25 m et 1.12 g/t gold over 4.5 m in a sheared (type of granite). Several anomalous results of 0.5 to 1.1 g/t gold over 0.75 to 2.25 m were also returned in other trenches in the granitic rocks.
GEOLOGY AND SHOWINGS MAP
PHOTO OF HEBERTO SHOWING (Looking West)
During spring 2013, Osisko carried out a 33km induced polarization survey over Heberto area. In November 2013, Osisko terminated its option on the project due to cuts in its exploration budgets.
In 2014, DIOS reprocessed available AU33West geological data. Mineral maps were used to define geochemical characteristics of auriferous fluids associated with large hydrothermal pathways within project. They show good correlation between gold and presence of pyrite, chalcopyrite and/or magnetite-hematite (oxidized system) at the margins of several intrusions interpreted from total field & vertical gradient magnetics and geological mapping.
Pyrite-Chalcopyrite versus magnetics
Moreover, these mineralizations are located within large halos of potassic-feldspar, silica, epidote, magnetite-biotite and hematite alterations. The last three may be indicative of a large hydrothermal-magmatic system characterized by strongly oxidized fluids.
Hematite-Magnetite-Epidote ALTERATIONS MAP
Silica-Potassic Feldspar ALTERARIONS MAP
Juxtapposition of structural measurements and magnetic data strongly suggests presence of buried intrusive domes within mineralized and altered area which are mainly developped along a north-south structural vector in the plutonic domain.
MAGNETIC DOME STRUCTURES VERSUS GOLD
Concentration of sulfidic mineralization along margins of distinctive magnetic intrusions is also coincidental with higher potassium content (ground spectrometry).
K2O VERSUS MAGNETICS
In 2014, detailed mapping of Heberto stripping delineated the APEX ZONE: a north-south striking mineralized envelope grading 1.89 g/t gold averaging all channels in a 7 m wide X 10 m long zone, open along strike, at depth and to the west. The APEX ZONE is hosted within an open anticline structure, with limbs dipping 40-50° towards each side, suggesting potential for widening of gold mineralization close to surface. Previous channel sampling on mineralized structure returned up to 5.18 g/t gold over 5 m. The overall average for 72 one-meter channel samples (up to 21.4 g/t gold/ 1 m) over the 30 x 10 m Heberto stripping is 0.74 g/t gold. The APEX ZONEconsists of 1-5% disseminated pyrite associated with quartz stringers/stockworks and biotite-sericite alteration, hosted within sheared and altered quartz-diorite intrusive. The APEX ZONEis bordered to the east by lower grade mineralization (50-450 ppb gold) consisting of traces-1% pyrite associated with dilatational flat fractures. Two 2014 samples grabbed from quartz veinlets bearing quartz-diorite intrusives returned 7.89 and 8.06 g/t gold.
DIOS will focus on Heberto and Robino areas. The concentric structures, locally associated with gold mineralization, combined with recent discovery of a magmatic-hydrothermal breccia pipe, suggest buried magmatic-porphyry domes. Detailed geological mapping in 2014 confirmed diorite-tonalite complex on road-accessible Au33W property, in which felsic intrusives were injected by dioritic plugs and related breccias. Brittle north-south structures controlled breccia setting, alteration and gold mineralization. Moreover, the significant regional gold in till train and anomalous gold background in fractured intrusive rocks are good indicators of a large buried mineralized system. The Heberto area is similar to a structurally-controlled oxidized (IRG) intrusion-related gold system.
IP VS GOLD SOILS
Horizontal Diamond Saw Channel Photos