Key Highlights

  • New infill results have been reported from the Rise and Shine deposit at the Bendigo-Ophir gold project in Central Otago.
  • The HG1 domain is the highest concentration of gold at the deposit.
  • A newly recognised deeper high-grade domain has been identified.
  • Further infill and diamond drilling, along with metallurgical and environmental work, is planned.

Santana Minerals (ASX:SMI) has reported new infill results from the Rise and Shine deposit at its Bendigo-Ophir gold project in Central Otago, New Zealand. The 4 November release focuses on the HG1 domain, which the company describes as the highest concentration of gold at the deposit and central to the planned early years of open-pit mining.

The best intercept was 26.9 metres at 13.0 grams per tonne gold from 152.3 metres in hole MDD537, with an estimated true width of 24.9 metres. Hole MDD536 returned 34.4 metres at 8.8 g/t from 160.7 metres, a true width of 30.6 metres, while MDD528 delivered 24.4 metres at 10.9 g/t from 165.7 metres.

Unusually for an exploration release, Santana quotes true widths alongside downhole lengths. That matters because drill holes rarely cross a mineralised zone at right angles, so downhole intervals tend to overstate thickness.

Does the model hold?

The main purpose of infill drilling is to test continuity between existing holes rather than to find new ounces. Santana says the current programme of 16 holes for 3,503 metres has reduced average drill spacing in the targeted early Mining areas from about 25 metres to 21 metres.

The company reports that assays have generally matched what its existing Mineral Resource model predicted. For a project heading towards development, that is arguably more important than any single high grade, because it lowers the risk that the early mine schedule rests on poorly understood geology.

On the western and southern margins of HG1, results showed the expected pattern of broad lower-grade material with isolated very high grades linked to coarse gold. Examples include 3.3 metres at 40.3 g/t in MDD531B and 5.2 metres at 6.7 g/t from 59.9 metres in MDD533. Coarse gold can make grade estimation harder, which is one reason closer spacing is valuable.

A second high-grade layer

The more novel finding is a previously unrecognised high-grade domain inside the existing low-grade LG1 domain, lying below and roughly parallel to HG1. Intercepts from this zone include 2.0 metres at 89.5 g/t from 197.0 metres in MDD528, 2.0 metres at 34.6 g/t from 209.2 metres in MDD534B and 4.2 metres at 14.5 g/t from 211.8 metres in MDD504.

Santana interprets this as part of a vertically stacked mineralised system and notes that the zone is commonly associated with dilatational breccias; visible gold was logged in such a breccia in MDD537. The intervals are narrow so far, and the company has not quantified what the domain might add. It is undergoing geological assessment before inclusion in resource modelling and mine planning.

Chief executive Damian Spring said the programme was confirming continuity in HG1 and uncovering a deeper high-grade domain, and that the results would be factored into the company's model. That is management's assessment; the effect on tonnes, grade and mine plan will only be known once the model is updated.

Other HG1 results in the batch included 17 metres at 5.9 g/t and 8.5 metres at 4.2 g/t in MDD535, and 10.2 metres at 10.1 g/t from 175.8 metres in MDD534B. Together with the headline holes, they suggest the high-grade domain is behaving consistently as drill density increases, which is the outcome an infill programme is designed to test.

What comes next

Santana has outlined further infill drilling, diamond drilling to extend existing Inferred resources and test deeper sub-vertical structures, and continuing metallurgical, environmental, geotechnical and hydrological work for pre-mining studies. None of these activities carried firm dates in the announcement.

The next meaningful checkpoints for investors are an updated resource model reflecting the tighter HG1 data and some indication of whether the deeper domain can be mined economically alongside the shallower zone.