new zone (now named ‘Thunder') DRILL HOLE ST23-03 DETAILS
ST23-03 was drilled to a downhole depth of 396m and intersected two main zones of visual copper mineralization. The drill hole was designed to test a near-surface MLEM conductor approximately 1km to the west of the high-grade copper 2750N Zone, and the edge of a moderately dense gravity anomaly close to the Southern Graben Fault (Figure 3). Corresponding upper and lower zones of copper sulfide mineralization were intercepted.
The upper zone of copper mineralization encountered within ST23-03 is a 76m thick interval of strong breccia and vein-style copper sulfides, with broad zones of semi-massive to massive sulfide from 32m downhole. The massive sulfides are dominantly chalcocite, with bornite and chalcopyrite (Figures 1 & 4), and represent a significant new discovery of near-surface copper mineralization.
The thickness and intensity of the mineralization of the new zone (now named ‘Thunder'), and high-grade 2750N and 2200N Zones along strike to the east, suggest that this high-grade mineralization and structural setting may be directly related to their proximity to the Southern Graben Fault. These faults are interpreted to be the primary source of plumbing for both the near-surface, and deeper copper mineralization.
Figure 4: Massive chalcocite (dark grey) in drill hole ST23-03 from approximately 57.4m downhole.
The lower zone of mineralization was intersected at 273m downhole and is interpreted to correlate with the sediment hosted copper mineralization intersected in drill holes ST22-10, ST23-01 and ST23-02. The 2m mineralized interval consists of broad fractures and dense anastomosing veins of chalcocite, bornite and chalcopyrite (Figure 5).
The copper sulfides are hosted within a sequence of organic rich and vuggy dolomudstones that are visually very similar to ST22-10, ST23-01 and ST23-02.
Figure 5: Breccia chalcocite (dark grey), bornite (purple/grey) and chalcopyrite (brassy) in drill hole ST23-03 from approximately 272.9m downhole.
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