VANCOUVER, British Columbia–(BUSINESS WIRE)–Aug 5, 2022–
Northisle Copper and Gold Inc. (TSX-V: NCX) (“Northisle” or the “Company”) is pleased to announce assay results from its 2022 Spring drill program at Hushamu. These new results continue to affirm the interpretation that higher grade mineralization exists in under-drilled areas of the modelled pit at Hushamu. In addition, HU22-06 was continued in copper mineralization for at least 200 meters beyond the outline of the modelled pit shell.
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Table 1: Hushamu 2022 Significant Intercepts. Copper and gold equivalent calculations based on the following metal prices which were used in the Company’s 2021 PEA (as defined below) on the North Island Project: Cu = US$3.25/lb, Au = US$1,650/oz, Mo = US$10/lb, Re = $1,256/kg. Calculations assume 100% recovery; totals may not add due to rounding. Note on equivalent calculation: Copper equivalent is determined by calculating total contained metal value/ tonne, dividing by the copper price, and then dividing the resultant number of pounds of copper by 2204.6. Gold equivalent is determined by calculating total contained metal value/tonne, dividing by the gold price, and then multiplying the resultant number of troy ounces of gold by 31.103. (Graphic: Business Wire)
Robin Tolbert, Vice President Exploration of Northisle stated “Drilling at Hushamu during early 2022 continues to demonstrate the potential for improved grade and tonnage at Hushamu. In addition, we have demonstrated that historical visual interpretations of the alteration profile at Hushamu may have underestimated the overall size of the mineralized portion of the system.”
Figure 1 shows the Company’s existing deposits as well as key exploration targets at the North Island Project. The Hushamu deposit forms the core of the technical report titled “North Island Copper and Gold Project Form 43-101F1 Technical Report Preliminary Economic Assessment” issued June 8, 2022, with an effective date of February 4, 2021 (the “2021 PEA”).
Hushamu 2022 Drill Results
Northisle has now received the assay results of the six drill holes from its 2022 Spring drill program at Hushamu (HU22-01 to HU22-06), which has the objective of converting in-pit Inferred Mineral Resources to Indicated Mineral Resources ahead of the Company’s planned pre-feasibility study. The mineralization remains open to the northwest and southeast of the deposit, and based on results released today is interpreted to be open at depth significantly past previous modelling. Significant intercepts from the 2022 Spring drill holes can be found in Table 1 above.
Drill hole collar locations for the 2022 drilling at Hushamu can be found in Table 2, and the drill holes are shown in context in Figure 2 with key sections showing the 2021 PEA proposed final pit outline as well as the surface projection of the Hushamu Mineral Resource estimate.
The significance of the additional 2022 Spring infill holes at Hushamu are:
- HU22-01 shows significant mineralization extends from hole H-12-03 along the base of the proposed pit bottom. This may add tonnes and maintain the mineral grades over a longer distance than previously estimated.
- HU22-02 shows a thicker combined mineralized interval than holes EC-184 and H-12-09 on either side of it. An additional hole will be drilled in the gap between these two holes.
- HU22-03 and HU22-04 were infill holes drilled to the south of the main mineralized zone. Both intersected leached altered zones with a few narrow copper intercepts 0.01% Cu.
- HU22-05 was part of a two-hole program to fill in the gap between H-12-08 and H17-02 and test the extent below the planned pit bottom. This hole showed mineralization extends to this point but not to depth. An in-fill hole between this hole and H17-02 is required to test to the south of an interpreted fault along Section 5613600E.
- HU22-06 indicates that mineralization extends significantly beyond the modelled outline of the 2021 PEA pit shell on Section 581000 E:
- Historical drilling generally ends at the interpreted interface of CMG alteration and propylitic alteration.
- XRF scanning of drill core in real time indicated that core contained copper below the previously interpreted bottom of CMG alteration, so drilling was continued.
- Results suggest future drilling should continue to greater depth and may represent a significant extension of mineralization.
- The spring drilling program continues to demonstrate the potential to improve tonnage and grade in an updated Mineral Resource estimate at Hushamu through both upgrading of existing blocks as well as extension of the overall orebody.
Figure 3 shows Section 580300E, where HU22-02 can be seen in the context of other drill holes.
Figure 4 shows HU22-01 on section 580500E in context of previous drill holes.
The drill hole structure log for H17-02 on Figure 5: Section 580700E indicates the presence of a fault zone from 307 m to 384 m, similar discontinuities in drill holes along UTM Easting 5613600E on other sections may explain the lower grades exhibited in these and other holes in this area. The objective of future additional drilling like HU21-04 on either side of these ’null’ holes is to increase the Mineral Resource in these and similar areas elsewhere in the deposit.
As Table 1 and Figure 6 indicates hole HU22-06 extended mineralization 1200 meters beyond the 2021 PEA modelled pit shell outline on Section 581000
Logging, Sampling, Assaying and Quality Control (“QA/QC”) Procedures
The diamond drill core logging and sampling program was carried out under a rigorous quality assurance / quality control program using industry best practices. Drill intersections in this release are typically HQ to 100 m and NQ thereafter to the end of holes. After drilling, core was logged for geology, structure, and geotechnical characteristics utilizing Geospark© core logging software, then marked for sampling and photographed on site. The cores for analyses were marked for sampling based on geological intervals with individual samples 3 m or less in length. Drill core was cut lengthwise in half with a core saw. Half-core was sent for assays reported in this news release. Prior to cutting core for assay bulk density was also determined on site by taking 20 to 25 cm lengths of whole core of each lithology at 10 m intervals. The ends of these were then cut at right angle to the core axis, retaining all pieces to be returned to the core box for later sample cutting and analysis. The diameter of each core sampled for bulk density was measured at each end with digital calipers to 3 decimal places and recorded. The length of the core was measured on four sides at 90 degrees to each other, to 2 decimal places and recorded. The software averaged the lengths and diameters. The mass of the dry core was measured twice on an Ohaus© balance to 2 decimal places. If no discrepancy occurred the measurement was recorded. If there was a discrepancy the measuring was repeated until no discrepancy between 2 measurements occurred. The density was calculated using the formula Bulk Density = π times r² times h (where r is radius of core and h is length of core). Certified standard masses are used to calibrate the scale balance used for bulk density determinations. The balance in the core logging area was levelled on a large concrete block to avoid vibration, was leveled, and surrounded by a wooden partition to avoid wind affecting the balance. The measurements were recorded in Geospark© logging software and Bulk Density calculated to 2 decimal places. In compiling assays on sections, intervals of less than 0.1% Cu, if less than 10 metres continuous width, within larger intervals 0.1% Cu were considered internal waste and included in the reported assays. If the interval was 13 m or greater, these assays were excluded from the compilation. Likewise, any intervals…