Oklo Resources

ASX-listed Graphex Mining is underway with drilling campaigns on the Lakanfla and Tabakorole gold projects, located in western and southern Mali, respectively.

This follows the acquisition by Graphex of the joint venture earn-in rights on Altus Strategies’ 100%-owned Lakanfla and Tabakorole gold projects in June, which were previously held by Glomin Services.

Read more: Altus and Graphex enter gold JV and royalty agreement in Mali

The Stage 1 drill programme, comprising 1 544 m of diamond drilling and 1 811m of air core drilling, was completed at the Tabakorole gold project. The drilling comprised eight holes of diamond drilling for 1 544 m and 92 holes of air core drilling for 1 811 m.

Results are expected to be released in August and will underpin the maiden JORC 2012 resource estimate for Tabakorole.

Tabakorole has a large historical resource with upside in grade and ounces – historical intercepts include:

  • 44 m grading at 3.3 g/t Au from 24 m  
  • 60 m grading at 2.9 g/t Au from 14m  
  • 16 m grading at 9.3 g/t Au from 80m

The diamond drilling programme satisfies the main requirement for the company to earn a 33% interest in Tabakorole under the joint venture with Altus Strategies.

Read more news on Mali

The Stage 1 drilling follows 2 042 m of air core drilling and 520 line km of ground magnetics conducted in early 2020 by joint venture vendor Glomin Services under the direction of Graphex Executive Director, Chris van Wijk.

The Stage 1 drilling was designed as due diligence on the drilling and deposit model and also as a first pass test of the company’s exploration strategy, which is focused on increasing the size and grade of the mineral resource by:

  • Testing interpreted high-grade plunge extensions beyond the depth of historical drilling;
  • Drilling untested gaps along the 3km strike of the deposit; and
  • Testing the 600m strike extension to the north-west.

In addition to the Stage 1 drilling, the company has continued to advance its conceptual understanding of Tabakorole following detailed analysis of work carried out post-2007 (including high-grade intersections not incorporated in the 2007 Tabakorole mineral resource estimate), on-site technical review of core and drillhole information, a review of the structural controls on mineralisation and an updated 3D model of the mineralised system.

Lakanfla exploration update

The Lakanfla gold project, which is located 6 km to the south-east of the tier 1 Sadiola gold mine (13.5 Moz production historically) and 35 km south-east of the Yatela gold mine (4.5 Moz production historically), hosts a significant number of active and historic artisanal gold workings which are coincident with major geochemical and gravity anomalies.

Historical drilling has returned encouraging intersections including 26 m at 5.1 g/t Au from 32 m (hole 04KRC- 02) and 18 m at 4.31 g/t Au from 34 m (hole 04KDD-06).In addition, several drillholes have intersected voids and unconsolidated sand at depths of up to 150 m below surface. However, none of the priority gravity low targets have been systematically drill tested.

Of the historical drilling that has been undertaken at Lakanfla, 35 holes coincide with the priority targets, however the majority of these holes were drilled no deeper than 75 m vertical depth and the exploration target is expected to be below this stratigraphic level at the bedrock-weathering interface. In comparison with the nearby large scale Yatela deposit, which is a direct exploration analogue, mineralisation was encountered at depths up to 220 m below surface and as such, the company believes that a valid exploration target of this style exists at Lakanfla.

The company is of the view that the major karst target identified by a 2014 gravity survey has not been drill tested and with the project showing geological and geophysical similarities to the Yatela deposit, an opportunity exists to carry out a structured drilling programme to test these anomalies.

Next steps

At Lakanfla, the company is reviewing historical geophysical data including the 2014 gravity survey results as well as magnetics and induced polarisation surveys to assess how such data can be reprocessed to further refine planned drill targets. The company has started making plans for the upcoming Stage 1 drill program of 3 500 m, to be completed by Q4, 2020.

Following the success of the high-resolution ground magnetic survey at Tabakorole, the company is planning an additional survey over the remainder of the tenement that was previously covered by airborne magnetics. Interpretation of recently acquired satellite imagery for input into a regolith model, combined with the compilation of historical geochemical data will allow us to evaluate the effectiveness of the previous regional exploration. This data will provide input into a regional exploration programme for follow up in the next field season.