Tectonic Metals Inc. has announced check drill assay results, including 104.5 g/t gold (Au) over 1 m, from quarter-core check assay sampling of the previously announced Michigan Zone drill hole TBDD21-002. The original sample from this interval returned 1.034 g/t Au over 1 m from 74 – 75 m downhole. A total of nine specks of visible gold (VG) were identified within a quartz vein from that sample during the initial logging of the drill core. This check assay demonstrates the presence of a significant coarse gold ‘nugget effect’. Drill hole TBDD21-002 is located in the heart of Michigan, which has 275 m of drilled mineralised strike to a confirmed vertical depth of 250 m with mineralisation open in all directions. Michigan is one of several gold zones at the company’s Tibbs Gold Project, Alaska, USA.
Highlights and key points
- Drill hole TBDD21-002 underwent multiple assaying methods (half core fire and metallic screen assaying along with routine quarter core check fire assaying). Comparison of assay results suggests that a gold nugget effect is present at Michigan consisting of a heterogeneous distribution of coarse gold particles, which appears to be controlled both by style (high-grade quartz-sulfide-gold veining) and spatial distribution of mineralisation (discrete structural corridors).
- Drilling at Michigan exhibits high-grade gold:
- 6.03 g/t Au over 28.95 m (2019).
- 6.71 g/t Au over 9.14 m (2020).
- 7.69 g/t Au over 6.12 m (2021).
- 104.5 g/t Au over 1 m (2021).
- 57.1 g/t Au over 1.52 m (2011).
- New interpretation suggests that these high-grade intercepts may be situated on a newly identified steep structure. This structure, tested by the 2021 diamond drill holes, is highly oblique to the historical drill orientation. Drill testing of this potential new structure will be a top priority going forward.
- Nuggety gold and VG have been observed at other mineralised zones at Tibbs, including the high-grade Gray Lead Zone 4km to the southwest of Michigan.
- Tectonic is initiating a programme of selective metallic screen assaying for all known intervals of quartz vein mineralisation and VG drilled during the 2021 season. The forthcoming assay results will allow Tectonic to further understand the extent and distribution of nuggety gold within the project area and how to best assay drill samples going forward.
A nugget effect results when a small sampling size fails to adequately represent the composition of the core tested due to the non-uniform distribution and/or coarse grain size of gold particles in the material sampled. A more representative assay value can be determined using metallic screen analyses, a widely used technique in the mining industry. A metallic screen analysis consists of one assay from the coarser fraction and a second assay from the finer fraction of a sample. The two values are then combined to provide a more representative weighted average gold value. Tectonic’s sampling methodology has been to always send the same side of the split core for assay, regardless of where any potential visible gold is noted, to eliminate bias in the sampling procedure.
Read the article online at: https://www.globalminingreview.com/exploration-development/07032022/tectonic-metals-announces-michigan-zone-assay-results/