The Cheechoo gold project is located in the Eeyou Istchee James Bay region of Quebec, less than 15 km from Newmont’s Éléonore gold mine.
The property consists of a main block of 121 claims as well as a secondary block of 35 claims located about 20 km to the west. These 156 claims totaling 81 km2, are fully owned by Sirios (with a royalty to Golden Valley Mines Ltd. ranging from 2.5% to 4% based on gold price on 145 claims).
The property straddles the suture zone between the Opinaca meta-sedimentary subprovince and the La Grande volcano-plutonic province. It is composed of both granitoids typical of the La Grande sub-province and metatexites typical of the Opinaca sub-province. The geology of the property consists of tonalite, meta-wacke, paragneiss, granite and pegmatite.
The gold mineralization is primarily hosted in a silicified and albite rich tonalite, with the presence of parallel or stockwork-type centimetric quartz veins or veinlets. It includes a very low sulfide content (<1%, pyrrhotite-arsenopyrite-pyrite) along with variable amounts of amphibole, biotite, chlorite, diopside, tourmaline and scheelite. Most of the gold occurs as free coarse grains. These overall characteristics are typical of Reduced Intrusion Related Gold Systems.
For more information, please consult the scientific article published by the Geological Survey of Canada in 2018 on the Cheechoo property.
The first resource estimation conducted on the property (December 2019), based on an open-pit constrained model, resulted in:
- Inferred resources containing 1.6 million ounces of gold (Moz), from 71.0 million tonnes (Mt) at an average grade of 0.69 grams of gold per tonne (g/t Au);
- Significant upside for expanding the maiden mineral resources with the potential to add an additional 25% more ounces that have been outlined on the Cheechoo property but require an agreement with the neighbouring property to access this material.
This data comes from the resource estimate (BBA Inc., Pierre-Luc Richard, geo.) whose results have been published in the December 11, 2019 press release.
Completed exploration work
As of December 2019, the exploration work conducted on Cheechoo amounts to 64,200 m of drilling (270 holes) and 3,200 m of channel sampling. (For more details, please consult the press release list announcing the drilling results.)
The main gold area (approximately 500 by 500 m) has been drilled with a 50 m spacing. In order to collect structural data, downhole logging surveys were completed on 57 drill holes.
The following work has also been conducted on the property:
- Ground magnetometer and induced polarization surveys (2012);
- Helicopter-borne magnetometer surveys (2014, 2017);
- Soil (humus) and till sampling surveys (2010, 2015-2017).
The work undertaken to date demonstrates the extent of the Cheechoo mineralized system. The mineralization spreads for more than 1,400 m along the tonalite/meta-sediments contact. (ref. February 8, 2018 press release) and up to 500 m towards the interior of the intrusion. Gold mineralization has also been tested down to 650 m below the surface.
Furthermore, the exploration work carried out to the west of the main area indicates that the mineralized envelope could extend to the west towards the Eclipse area.
High-grade gold intervals are frequently intersected within the low-grade envelope. As of January 2020, a total of 37 high-grade zones have been defined and modelled, including the Jordi Zone, which is distinguishable by the presence of gold bearing pegmatite and quartz-feldspar veins with visible gold. This zone, which is 5 to 10 m thick, is continuous for more than 300 m laterally and for nearly 200 m downdip, while remaining open at depth. About 50 drill holes have intersected it, with grades up to 56.4 g/t Au over 8.2 m.
Mineralization at Depth
Intervals of medium to high-grade gold were intersected at depth in the tonalite including, for example, drill hole #82E (2.0 g/t Au over 16.0 m, including 7.4 g/t Au over 3.1 m) at a depth of more than 600 m and drill hole #98 (17.4 g/t Au over 3.0 m, including 159.3 g/t Au over 1.0 m) at a depth of more than 400 m.
Gold mineralization was also observed in meta-sedimentary rocks in deeper drill holes such as drill hole #98 (1.7 g/t Au over 34.9 m, including 4.4 g/t Au over 8 m) at a vertical depth of 505 m and drill hole #82E (1.1 g/t Au over 24 m, including 4.6 g/t Au over 2.5 m) at a vertical depth of 491 m (ref. May 30, 2017 press release).
The Eclipse area is located at more than 750 m west of the main area and represents the continuity of the Moni showing (from the neighboring Éléonore South property). This area’s mineralization is characterized by near-surface, very high-grade gold veins, which are hosted in a low-grade tonalite.
These veins have been intersected by multiple drill holes, including drill hole #95 (11.9 g/t Au over 13.5 m, including a quartz vein with visible gold assaying 65.1 g/t Au over 2.1 m) and drill hole #99 (11.2 g/t Au over 10.6 m, including two intervals with visible gold assaying 63.3 g/t Au over 1.0 m and 50.5 g/t Au over 1.0 m).
Other exploration targets
North-West Area. 1.5 km north-west of the main area, many gold mineralized intervals were intersected by drill holes #47 (5.5 g/t Au over 1.0 m and 5.3 g/t Au over 1.1 m), #48 (1.6 g/t Au over 8.3 m), #63 (3.4 g/t Au over 1.1 m) and #64 (1.9 g/t Au over 3.3 m).
Till Area. 3 km north-west of the main area, gold anomalies have been detected in till samples. In this area, drill hole #73 intersected anomalous gold grades, including 0.8 g/t Au over 5.4 m.
Metallurgical tests conducted in 2019 on samples representative of Cheechoo’s mineralization obtained gold recovery rates up to 97%, including 88% by gravimetric process.
The tests also demonstrated potential to concentrate the sulfides in the gravity process tailings using flotation. Note that the tailings from the treatment of Cheechoo samples have a very low sulfides content, in the order of less than 0.2%. Cyanidation tests also show a low consumption of reagents (< 0.6 kg/t of NaCN and < 1.1 kg/t of Ca(OH)2).
For more details, please consult the September 2, 2019 press release.
The Cheechoo project has numerous positive characteristics, including:
- A strong exploration potential;
- Excellent gold recovery (up to 97% of recovered gold, including 88% by gravity);
- A low strip ratio of 1.1:1;
- Proximity to existing infrastructures, including :
- Road access;
- An airfield;
- A hydro-electric power line;
- The Éléonore mine camp;
- A cell tower.
The Sirios team focuses its efforts for the purpose of increasing the grade and size of the deposit with additional drilling campaigns (as well as with discussions with adjacent property owners).
The next steps of Cheechoo’s development planned by Sirios are the following:
- February-March 2020: Drilling campaign
- 2020: Impact studies
- 2021: Preliminary Economic Assessment (PEA)
- Prefeasibility Study (PFS)