McEwen aggressively exploring Grey Fox Complex east of Timmins
McEwen Mining Inc. is providing new assay results from the Grey Fox deposit, part of our Fox Complex. The results demonstrate intriguing exploration targets at depth and attractive near-surface gold grades with the potential to be recovered utilizing lower-cost open-pit mining methods.
Gold at Grey Fox has been found in multiple zones, including Gibson, Whiskey-Jack, 147 and Grey Fox South (GFS). The current resource estimate for Grey Fox is 1,168,000 oz gold at a grade of 4.80 g/t Au Indicated and 236,000 oz gold at 4.35 g/t Au Inferred. An updated resource estimate will be completed in late September. Much of the drilling performed in 2023 and continuing into 2024 was focused on increasing the existing resource in addition to identifying new mineralized horizons.
Geological interpretations suggest that Grey Fox sits stratigraphically above the mineralization of the Black Fox & Froome mines. Consequently, there is potential for deeper Black Fox & Froome style mineralization directly below some of the Grey Fox zones. Historical production from these two mines is more than 1,000,000 oz gold.
Figure 1 shows the location of the Grey Fox zones relative to the Black Fox and Froome mines, on the same large property, separated by approximately 3 kilometers (1.9 miles). There has been limited drilling between Black Fox and Grey Fox, despite historical drill results that indicate similar rock types associated with the A1 Fault, the principal structure that controls the mineralization at Black Fox.
Gibson Zone
The Gibson zone has a history that made it an obvious target. A bulk sample taken in 1989 had historical documentation suggesting an average gold grade in excess of 27 g/t Au. Results from our recent drilling have established Gibson as a high priority target. The Gibson zone consists primarily of a syenite intrusion with sediments lying to the East (see Figure 2). This geological setting is similar to the Young-Davidson Mine, which has estimated gold reserves of about 3,300,000 oz gold at a grade of 2.3 g/t Au. This mine is located about 100 kilometers (62 miles) southwest of Grey Fox.
In Figure 2 we illustrate some of the newly received drill intercepts at Gibson, which are conveniently located close to surface and close to the historical ramp used to take the bulk sample (e.g., 22GF‑1366: 8.8 g/t Au over 3.9 m and 24GF‑1397: 17.4 g/t Au over 4.2 m). In addition, these results demonstrate the potential for higher grading mineralization within the current resource.
We have just commenced an aggressive follow-up infill program at Gibson, designed to identify near-term mineralization. Figure 3 shows the first two holes (24GF-1452 and 24GF-1453; assays pending) for this program, drilled in proximity to the Gibson Ramp. Both drillholes have multiple occurrences of visible gold (VG). Much of the VG is associated with existing mineralized lenses, indicating the current resource model is performing well i.e., the mineralization is being intersected where it is anticipated to be present.
Earlier drilling in the sediments to the east of the Gibson syenite also generated attractive assay results (e.g., 21GF-1333: 5.6 g/t Au over 10.2 m from 386 m to 403.6 m downhole, at 365 m elevation), which shows the possible extension of favorable mineralization. In addition, limited recent deep drilling at Gibson showed evidence for mineralization at depths greater than 600 m (e.g., 23GF-1389: 4.4 g/t Au over 5.9 m within the Gibson syenite), indicating the resource growth potential for the Grey Fox area. Many of the intercepts reported for the Gibson zone are also open in most directions, including at depth.
Whiskey-Jack, GFS & 147 Zones
The Whiskey-Jack zone is the highest grading portion of the Grey Fox deposit, with current Indicated resource of approximately 80,000 oz gold at a grade of 7.0 g/t Au and an Inferred resource of approximately 43,000 oz gold at a grade of 6.1 g/t Au. Located at the NW corner of the current Grey Fox resource, it is associated with a local NW bend in the stratigraphy controlled by the A1 splay fault (see Figure 2). The A1 fault is interpreted to extend from Black Fox south to Grey Fox and may mark the boundary between shallow Grey Fox style mineralization and deeper-seated Black Fox style mineralization. A regional exploration campaign is currently underway at Grey Fox to test for this deeper style of mineralization East of the A1 fault and to verify historical drilling, which indicated mineralization in that area that could extend northwest back to Black Fox.
Geological interpretations suggests that the mineralization at Whiskey-Jack extends from less than 50 m below surface down to a depth of at least 275 m and remains open at depth.
Two other targets are the GFS and 147 zones, located near the Southern edge of the Grey Fox deposit. Figure 2 shows the locations of the newly received intercepts for both zones. The better gold grades and intercept widths are generally located within the north-south oriented variolitic mafic volcanics (e.g., 24GF‑1426: 586.7 g/t Au over 0.5 m and 24GF-1424: 14.3 g/t Au over 5.0 m). This is likely due to their enrichment in iron, which is a more favorable host rock and is a high priority target at GFS. The very high-grade value seen in 24GF-1426 also warrants additional follow-up drilling. Mineralization at GFS also begins at shallow depths (less than 50 m) and thus is amenable to open pit mining methods.
The following features make Grey Fox a strong candidate for open pit mining:
- The gold grades are above average for an open pit mine;
- Relatively shallow overburden;
- Much of the gold mineralization identified starts at less than 50 m below surface with the majority of the current resources less than 300 m below surface;
- Much of the mineralization is hosted in sub-parallel ‘stacked’ lenses located in proximity to each other with a steep (approx. 70⁰) dip, which means they are ideal for surface mining e.g., more optimal blasting patterns and less dilution, with a potentially low strip ratio.
An active exploration program will continue throughout the year and into 2025.
Figure 1 – Surface Plan View of the Geology for the Black Fox and Grey Fox Deposits
Figure 2 – Plan View Map for the Grey Fox Area With Highlighted Assay Intercepts
Figure 3 – Mineralization in Proximity of the Historical Gibson Ramp
(Cross Section Looking North-East)
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