Source: Billion Photos, Shutterstock
- Altan Rio undertook a Downhole EM survey on two of the drill holes on the Pilot deposit.
- The survey identified sulphide-rich zones intersected in drillhole PARC005 and indicated possible high-grade gold mineralisation.
- Altan Rio may undertake follow up drilling to test the source of conductor and further Surface EM surveys on the deposit.
West Australian-focused gold explorer Altan Rio Minerals Limited (TSXV:AMO.H) says it has encountered possible high-grade gold mineralisation at its Pilot Deposit in the prolific gold producing Southern Cross Greenstone Belt.
The Canadian-listed company recently carried out Downhole Electromagnetic (EM) geophysical surveys of all technical data and information obtained from the Phase 1 drilling campaign at Pilot which consisted of 10 holes to test mineralisation along strike and at depths below the existing open pit.
Significant grade from PARC005
One of the drillholes from Phase 1 - PARC005 - returned sulphides of up to 30% in an interval of 201m-206m associated with gold mineralisation of 5m @ 13.93g/t Au from 201m within a broader mineralised intercept of 8m grading @ 9.65g/t Au from 199m.
Perth-based Newexco Exploration Pty Ltd was commissioned to investigate the application of DHEM in order to target gold mineralisation in sulphide-rich zones. Newexco is a consultancy group that specialises in geophysical and geological services.
Additionally, drillhole PARC014 was surveyed as a follow-up to provide additional information obtained in PARC005 hole.
Drill collar plan with downhole EM conductors projected to surface on Pilot deposit (Image source: Company update, 23 March 2021)
Findings of the Survey
The Downhole EM and Surface EM survey is a new development in the geophysical survey works on gold projects and are extensively used by the ASX listed gold explorers, including Bellevue Gold Limited, Apollo Consolidated Limited and Benz Mining Corp.
The DHEM survey on PARC005 delineated a high-frequency early-time on/off hole conductor at a depth of 170m (PEM 3). The conductor was coincident with the reported gold intercept of 13m @ 4.48g/t AU from 159m and another conductor was identified at a depth of 200m. The presence of the conductor at this depth, interpreted by Newexco, as an off-hole edge intersection with an anomaly. The source of the conductor is interpreted towards the south and below the hole (PEM 4).
For the hole PARCC014, the EM survey identified two on-hole conductors. The first was a weak on-hole anomaly at the depth range of 140-145m (PEM 1), and another one at a depth of ~240m (PEM 2). Both of these conductors are interpreted as a zone of a low percentage of disseminated pyrite and pyrrhotite with low-grade gold.
An anomaly was also identified at the same depth of 200m, and the source was interpreted towards the north and below the hole (PEM 4).
Pilot Longitudinal Section (Image source: Company update, 23 March 2021)
The Downhole EM survey interpreted both the results from the same source. Both the drillholes identified an off-hole conductor at a depth of around 200m. The modelling of the source using a single plate was done in accordance with the findings of the survey. The plate's estimated dimension is around 130m in strike extent with a depth extent of 200m commencing immediately below hole PARC005 where there is a reported intercept of 8m grading @ 9.65 g/t from 199m.
The findings of the EM survey can be summarised in the below table:-
Mr Paul Stephen, CEO of Altan Rio, shared his views on the excellent survey result and commented: -
Copyright © 2021 Kalkine Media Pty Ltd. (Data source: Company update, 23 March 2021)
Follow up works on the deposit
Based on the findings, Newexco has recommended Altan Rio drill test the source of the DHEM conductor (PEM 4) at a position down dip from the intersection in PARC005 as well as conduct surface EM surveys along strike to both north and south of the Pilot pit.
As of 9 April 2021, Altan Rio shares closed the day trading at $0.16 on the TSXV with a market cap of $13.47 million.
Note: All currencies are in the Canadian dollar.