Golden Deeps has started a deeper diamond drilling programme at its Graceland discovery in Namibia, initially targeting 10 holes as the Australian explorer tests whether high-grade copper, silver, zinc, lead and germanium mineralisation found close to the surface continues into larger sulphide zones at depth.
The drilling is targeting three priority Induced Polarisation sulphide anomalies along the Gossan 1 corridor in the Otavi Mountain Land Critical Metals Belt, where earlier exploration returned grades of up to 9.2% copper, 417 grams per tonne silver, 23.2% zinc, 8.2% lead and 118g/t germanium.
The programme marks a shift from the shallow drilling and surface exploration that established the high-grade mineralisation at Graceland towards testing what Golden Deeps believes could be deeper, potentially significant sulphide systems.
The company said the first 10 diamond holes will test down-plunge extensions of the high-grade zones already identified at Gossan 1 and Gossan 1 East, as well as IP chargeability anomalies beneath the two prospects. A second stage will target deeper extensions below 100 metres and the Gossan 1 Far East anomaly, described as the largest and strongest of the three IP anomalies identified so far. The Far East target has no surface expression and remains open both to the east and at depth.
Golden Deeps chief executive Jon Dugdale said the deeper programme follows systematic exploration, including rock-chip and channel sampling, shallow drilling, and IP surveys.
“We are very pleased to have commenced our deeper diamond drilling program at the exciting Graceland discovery in Namibia – to test the high-priority critical metals targets identified within the Gossan 1 corridor by our previous systematic exploration programs,” Dugdale said.
He said the earlier results gave the company confidence that the anomalies now being drilled could represent copper-silver-zinc-lead and germanium-bearing sulphide zones with the potential to become significant discoveries.
The deeper targets are particularly important because Golden Deeps is comparing their geological, structural and geochemical characteristics with the historic Tsumeb deposit, about 30 kilometres north of Graceland.
Tsumeb produced 27 million tonnes grading 4.3% copper, 10% lead, 3.5% zinc, 95g/t silver and 50g/t germanium. Its main orebody extended substantially deeper than the relatively modest surface gossan that originally indicated its presence. This feature underpins Golden Deeps’ strategy of testing beneath the high-grade surface and shallow mineralisation at Graceland.
“Adding to our confidence is the fact our drilling targets have a similar geological and structural setting, and geochemical footprint, to the world-class Tsumeb deposit, located just 30km to the north of Graceland,” Dugdale said.
Fresh results from four earlier shallow diamond holes have strengthened the company’s case for testing deeper. At Gossan 1, hole GLBPD009 returned 8.20 metres grading 3.5% copper equivalent from 6.8 metres, including 2.12 metres at 6.2% copper equivalent. Individual assays within the hole reached 23.18% zinc and 118g/t germanium.
At Gossan 1 East, GLBPD007 intersected 4.48 metres grading 4% copper equivalent from 2.52 metres, including 2.28 metres at 7.3% copper equivalent and 1.12 metres at 13% copper equivalent. A 0.30-metre interval within the hole returned 9.19% copper and 417g/t silver.
The company said these shallow results demonstrate continuity of mineralisation below the outcropping gossans. At the same time, the deeper drilling will now test the primary sulphide zones associated with the IP chargeability anomalies.
Graceland forms part of Golden Deeps’ broader position in the Otavi Mountain Land, where its 80%-owned subsidiaries hold six exclusive prospecting licences covering more than 440 square kilometres. The portfolio also includes Abenab, Nosib and Khusib Springs, along with several other base- and critical-metals prospects.
Exploration at Graceland has so far outlined a mineralised corridor extending more than three kilometres along strike and about one kilometre wide. Within it, IP modelling has identified three significant chargeability and low-resistivity anomalies extending for more than 800 metres east of Gossan 1 and remaining open eastwards and below 200 metres.
The new programme will therefore test whether the high grades already established near surface are connected to substantially deeper sulphide mineralisation, with Golden Deeps saying drilling will continue for several months and results will be released as they become available.
