Norfolk Metals is re-assaying old copper core for gold at its Carmen project in Chile as it seeks to verify historic drill results and exploit a new zone that is sporting visible copper outcrops. The project is in Chile's copper-rich Atacama region where fresh targets are now emerging in the nearby Higueritas Belt.
Norfolk is ramping up its maiden drilling campaign at Carmen, with reverse circulation rigs now working to validate historical shallow high-grade historical copper intercepts along the Tabaco Thrust and fresh targets emerging in the adjacent Higueritas Belt.
The program also seeks to verify the existence, tenor and extent of gold mineralisation that has been reported from previous work in the area.
The company has completed 29 of 34 planned reverse circulation (RC) holes totalling 2176 metres out of an allocated 2510 metres, with the 30th hole currently in progress on an 8-hour day-shift basis.
Several planned drill collars from the program have been brought forward into the RC phase of drilling to expedite the confirmatory drilling of historical high-grade intercepts as the company seeks to wrap a JORC resource around the project that is clearly well mineralised. Two RC holes are also planned for the project expansion area within the nearby Higueritas Belt.
Norfolk Metals’ executive chairman Ben Phillips said: “The RC drilling phase is edging towards completion with the inclusion of previously planned DDH collars to be drilled within the RC phase. These new RC collars include important confirmatory drilling. The re-analysis of historical high grade intercept diamond core, including gold analysis, has also commenced.”
The company says it expects to release all of its RC drill assays upon completion of the drilling and when compilation of all relevant data from the program has been received and interpreted, with accompanying plan and sections.
It expects to be in a position to present all of the information later in the quarter - including confirmatory RC twins of historical drill holes – one of which came in at 63m going 1.45% copper from just 45m, including 24m at 2.15% copper and 14m at 1.77% copper.
With RC work wrapping up soon, the diamond rig will take centre stage with up to 15 diamond drill holes for 2575 metres to be drilled on a 24/7 basis to probe the deeper sulphide potential below the near-surface oxide blanket.
Focus has sharpened on the western side of Section 10,000NE, where RC drilling is planned to twin historical holes to validate elevated copper grades tied to structural dilational jogs along the hanging wall of the Tabaco Thrust.
This part of the RC drilling program, brought forward from the confirmatory collars planned for the diamond phase, aims to establish support for the project's historical foreign NI 43-101 copper oxide resource of 5.6 million tonnes at 0.6% copper.
That resource is not reported in accordance with the JORC Code and has not yet been subject to sufficient work to classify the foreign estimate as a JORC compliant Mineral Resource.
However, if sufficient work can be undertaken on this part of the deposit it could represent a future JORC-compliant resource ripe for expansion, possibly via heap-leach development.
To gain stronger support for its data integrity, Norfolk has selected several diamond holes put in by IPBX in 2006 which it is re-logging and cutting to provide quarter-core that will be re-assayed for copper and gold, focussing on high-grade zones to confirm polymetallic potential.
IPBX is a now-dormant Canadian junior mining company that was active in the mid-2000s. It undertook diamond drilling at the Tabaco zone in 2006, hitting high-grade copper intercepts below the resource.
Selected intercepts being re-tested in high-grade oxide zones within the foreign resource envelope include one historical hole which delivered 31m assaying 1.21% copper from 24 metres; and a second hole which gave up 27.5m at 1.12% copper from 1.5m, including 11.5m at 1.88% copper.
A third hole includes intercepted 19.4m at 0.61% copper from 4.6m, containing a higher-grade segment of 7.4m at 1.45% copper, while a fourth hole delivered a standout 4m at 3.67% copper from 20 metres, including 2m at 7.22% copper.
In addition to the near-surface oxide potential, Norfolk is also looking at IPBX’s deeper hits below the foreign resource which are also in the crosshairs for validation.
The selected holes include one which encountered 26m at 1.58% copper from 29m a second hole which delivered the 63m hit at 1.45% copper.
A third hole from below the resource that will be re-assayed logged 52m at 0.92% copper from 66m depth
Norfolk has also established access to the nearby 7.5km-long Higueritas Belt, a distance of about 2.5km southeast of the Carmen – Tabaco – Dolores trend.
The Higueritas Belt roughly parallels the Carmen-Tabaco trend and is largely untested but Norfolk has identified strong surface indications of copper mineralisation from its initial access work and prospecting in the northern part of the belt.
Reconnaissance mapping at Higueritas has identified several old copper workings which appear to be associated with northeast-southwest and north-south striking structures which are bounded by NW to NNW northwest to north-northwest district-scale faults.
Strong copper oxide mineralisation has been identified along a mapped north-south to north-northeast trending structure in a volcanic breccia that appears to correlate with a strong IP chargeability anomaly at 250 metres depth over volcanic breccia.
Norfolk also plans to put in a follow up diamond drill hole to test a large coincident IP anomaly over this area across the 200m-wide breccia host.
Channel chip and panel samples from mineralised outcrops have been dispatched to Australian Laboratory Services for assay, while two RC holes of 150m depth each are slated to probe deeper beneath surface oxides and the interpreted upper zone of the IP anomaly.
Encouragingly, there are four distinct strong IP anomalies ranging between 0.5 and 1.5km in strike length along the belt for a combined total of about 5kms of strike which are primed for further mapping, soil sampling, and targeting.
Spanning 46.6 square kilometres across 22 licences in Chile’s Huasco Province, the Carmen-Tabaco Belt is 8.5km long and hosts copper–silver–gold mineralisation in an abundance of key structures, some of which are of regional scale.
Reference to low-grade gold is historical and is drawn from previous explorer IPBX’ drilling at Tabaco/Carmen which showed consistent trace gold in the range 0.1–0.3g/t gold, with copper-silver mineralisation in skarn and breccia and was referred to in the NI 43-101 foreign resource estimate (5.6Mt @ 0.6% copper) referenced by Norfolk.
The near-surface oxide deposit at Carmen appears to be ideal for low-strip, rapid-payback operations amid Chile's global copper dominance.
With rigs humming and new prospective belts opening up, Norfolk is charging ahead to sort out the structures, geochemistry and mineralisation extent of Carmen’s oxide blanket and underlying sulphide zone in the world's top copper haven that just might also be harbouring some gold.
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By Doug Bright
