Infill Drilling Supporting DFS Commences at Tumas
The drill program, due to commence 12 February, will initially focus on Tumas 3 East and West and is part of a larger four-month program that will also extend to drilling of the Tumas 1 East deposits.
In all, a total of 700 to 800 RC holes are planned to be drilled totalling approximately 15,000m.
Drilling is targeting the Tumas deposits (Figure 1), starting at Tumas 3 and ending at Tumas 1 East to infill existing wider-spaced drilling areas, better define the current remaining 51.2Mlb grading 249ppm U3O8 of Inferred Mineral Resource and upgrade this Resource to Indicated and Measured categories.
All drill holes will be surveyed to provide equivalent uranium values based on down-hole radiometric gamma logging, carried out by qualified operators using a fully calibrated AusLog gamma logging system.
INFILL DRILLING AS PART OF THE DFS
Infill drilling is being undertaken to provide for additional Indicated Mineral Resources as input into an updated Ore Reserve estimate, for the recently commenced Tumas Definitive Feasibility Study (DFS).
The Inferred category of mineralisation established within the deposits is remarkably consistent over an extensive length. The Company is confident that the remaining Inferred Mineral Resources associated with the Tumas deposits will convert to Indicated Mineral Resource, at a conversion factor similar to that achieved for the recently announced PFS.
The uranium mineralisation occurring within the Tumas palaeochannel is of the calcretetype, located within an extensive, 125km, mainly east-west trending, palaeochannel system.
This mineralisation occurs in association with calcium and magnesium carbonate precipitations (calcrete) in clastic fluvial sediment filled palaeovalleys. Uranium minerals are dominated by carnotite, a uranium vanadate. The grade of the uranium mineralisation may vary considerably over short distances (metres), however at a larger scale (+100m and kilometres) the mineralisation is persistent and predictable both laterally and along the channel. The geology of this type of mineralisation is well understood, having been explored over many years. The Langer Heinrich uranium mining operation occurring within an adjacent palaeochannel system 30km to the north-east, mined this type of deposit.
To date, only 65km of the 125km Tumas palaeochannel system has been adequately tested, delivering a total calcrete resource base of 110Mlb at a 100ppm eU3O8 cut-off grade and an average grade of 251ppm eU3O8. Of this total Mineral Resource, 52.6Mlb eU3O8 at 245ppm are of the Indicated JORC category occurring in the Tumas 1, 2 and 3 deposits.
These were utilised in the Ore Reserve determinations for the PFS.
Infill drilling in 2020 at Tumas 3 to upgrade a portion of the existing Inferred Mineral Resources succeeded in converting 95% of this Mineral Resource to Indicated Mineral Resource status. In the adjacent Tumas 1 and 2 deposits, Indicated Mineral Resources comprise 95% of the Mineral Resource base associated with these deposits suggesting a consistent overall conversion rate of 95% over 25km of mineralised palaeochannel. It is expected that similar conversions may be achieved in the drill programs already planned as a component of the DFS. Consequently, the Company is targeting to convert approximately 95% of the currently defined Inferred calcrete Mineral Resources remaining at Tumas 1 East and Tumas 3 East and West to the higher JORC categories. Figure 2* shows the location of the uranium deposits within the Tumas palaeochannel system.
Since the host rock, type, grade and shape of the uranium mineralisation in the Tumas palaeochannel is very consistent, it is reasonably assumed, based on the Mineral Resource conversions already achieved, that the current Inferred Mineral Resources of 51.2Mlb eU3O8 may convert to Indicated material at similar rates as previously achieved.
The successful resource upgrade, infill drilling program, undertaken during the PFS succeeded in converting 63% of the 42.9Mlb Indicated Mineral Resources at Tumas 1, 2 and 3 (at a 150ppm eU3O8 cut-off grade) to 30.1Mlb eU3O8 of Ore Reserves.
As the forthcoming infill drilling program is targeting lateral extensions to the Tumas 3 deposit and the conversion of the shallow Tumas 1 East deposit, in total this upgraded material is expected to contribute materially to an updated Ore Reserve for DFS consideration at a rate similar to that already achieved in the PFS.
*To view tables and figures, please visit:
About Deep Yellow Limited
Deep Yellow Limited (ASX:DYL) (OTCMKTS:DYLLF) (Namibian Stock Exchange:DYL) is a differentiated, advanced uranium exploration company, in predevelopment phase, implementing a contrarian strategy to grow shareholder wealth. This strategy is founded upon growing the existing uranium resources across the Company's uranium projects in Namibia and the pursuit of accretive, counter-cyclical acquisitions to build a global, geographically diverse asset portfolio. A PFS has recently been completed on its Tumas Project in Namibia and a DFS commenced February 2021. The Company's cornerstone suite of projects in Namibia is situated within a top-ranked African mining destination in a jurisdiction that has a long, well-regarded history of safely and effectively developing and regulating its considerable uranium mining industry.
Deep Yellow Limited