- Resource extension drilling produces an overall Inferred Mineral Resource estimate of 31.2Mlb grading 377ppm eU3O8 for the expanding Tumas 3 deposit.
o A 32% resource growth achieved while maintaining the average grade.
- In 18 months have doubled the pre-2017 32.1Mlb palaeochannel related Mineral Resource base on the Reptile Project, now reaching 63.3Mlb grading 301ppm eU3O8.
o Highly positive progress continues to advance the project toward achieving stated calcrete mineral resource target.
- Drilling planned west of Tumas mineralisation remains open to further enhance resource base
o 85km of uranium fertile palaeochannels offering highly prospective targets remain to be properly tested.
- Mineralisation is calcrete associated and hosted in palaeochannels, similar to the Langer Heinrich uranium mine located 30km to the north-east.
A 4-month resource extension RC drilling program was completed in June 2018, immediately east and west of Tumas 3 (see Figure 1 in link below). Drilling added 6km to the previously identified 4.4km long Tumas 3 discovery and defined extensive uranium mineralisation. Of the 274 RC holes drilled for 6,781m, 125 returned positive results - an overall 46% success rate.
The expanded Tumas 3 uranium resource has increased the Company's surficial calcrete palaeochannel Mineral Resource base on its Namibian projects by a significant 62% and now totals 81.3Mlb U3O8.
The mineralisation at Tumas 3 occurs as a distinct mineralised body separate from the other uranium mineral resources the Company identified previously within these palaeochannels in its Tumas 1 & 2 and Tubas Red Sands/calcrete deposits (see Figure 1 in link below).
The palaeochannels occurring away from these deposits and Tumas 3 have only been sparsely drilled along widely spaced regional lines in part with large sections remaining completely untested.
As previously reported Deep Yellow has identified 125km of prospective palaeochannel systems providing targets where large sections remain inadequately tested. The very encouraging follow-up drilling just completed identified a further 6km of extensive uranium mineralisation. This was targeted to expand the maiden Resource as announced 27 Sept 2017 at Tumas 3 and has produced a cumulative 63.3Mlb eU3O8 attributable to the Reptile Project palaeochannels. With this addition the Company is notably advancing its calcrete resource base towards its stated total Exploration Target(see Note below) of 100 to 150Mlb at a grade range of 300ppm to 500ppm for this type of uranium mineralisation. Deep Yellow's total JORC conforming uranium Mineral Resources on its Namibian projects are shown in Appendix 1 (see link below).
Note: With the additional resources announced herein, the Company has now determined an MRE of 81.3Mlb of calcrete mineralisation (or 81% of the lower range of the Exploration Target. The Company however acknowledges that the potential quantity and grade of the Exploration Target is conceptual in nature, and that there has been insufficient additional exploration to estimate an expanded Mineral Resource at the date of this report. Additional exploration is planned; however, it is uncertain if this will result in the estimation of an additional expanded Mineral Resource. From the review and evaluation of calcrete associated mineralisation already identified on the Company's tenements which commenced in the December 2017 Quarter and the exploration carried out over recent months, the Company has a greater understanding of the stratigraphy of the palaeochannels which host mineralisation. This work has provided renewed confidence that mineralisation is likely to be identified in targeted but contiguous areas on the Company's tenements.
Targeted tonnage/grades are based on results and understanding from work carried out over past 10 years in this region. The Exploration Targets are planned to be tested over the next 12 to 24 months by continued exploration programs predominantly drill testing of targeted areas.
Tumas 3 Mineral Resource Estimate Summary
The Mineral Resource was estimated by Ordinary Kriging. Cut-off grades used for the expanded MRE included 100, 150, 200, 250, and 300ppm eU3O8 and the Inferred Mineral Resources derived from these cut-off grades indicate the mineralisation remains robust and consistent (see Table 1 in link below).
The expanded MRE for the extended Tumas 3 deposit at a 200ppm cut off gives an Inferred Mineral Resource of 31.2Mlb at 377ppm eU3O8 as shown in in Table 1 (see link below). The 200ppm eU3O8 cut-off has been selected as being the most appropriate for headline reporting of the resource estimations.
ASX Additional Information
The following is a summary of the material information used to estimate the Mineral Resources as required by Listing Rule 5.8.1 and JORC 2012 Reporting Guidelines
Deposit Parameters: The Tumas 3 uranium mineralisation is of the calcrete type located within an extensive mainly east-west trending palaeochannel system. The uranium mineralisation occurs in conjunction with calcium carbonate precipitations (calcrete) in sediment filled palaeovalleys. Uranium is the only economically extractable metal in this type of mineralisation although vanadium production can be considered if the price for vanadium becomes high enough. Uranium minerals mainly include uranium vanadates. The geology of this type of mineralisation is well understood having been explored over a number of years. The Langer Heinrich uranium mine located 30km to the north-east exploits this type of deposit and has been mined since 2007.
The mineralisation domains used for the current extended MRE study were interpreted to capture continuous zones of mineralisation above 100ppm eU3O8. The mineralisation included in this study has a strike length of approximately 10km and ranges in width 100m to 900m extending to a depth of 40 to 50m averaging around 25m below surface along the main Tumas channel. This includes the 3km of mineralisation encountered along 3 associated tributary channels. The mineralisation occurs in a reasonably continuous, seam-like horizon and extends west beyond the currently drilled area. It is closed off to the south-east and remains open to the west.
Drilling for the project was based on RC methods only. Drill holes used in the MRE included the 274 recently drilled holes totalling 6781m, 462 holes drilled in 2017 for 12,323m and 338 historical drill holes totalling 8,343m drilled by Deep Yellow between 2011 and 2012. Drilling achieved recoveries around 90%. All drill chips were geologically logged and their radioactivity was measured. All data were added to the database.
The 2017 and 2018 drilling programs were carried out on a spacing of 100m x 100m. Around the tributary palaeochannels drill spacing was reduced to 50m x 50m if required. Pre-2017 drilling carried out by the Company was along regional 2km spaced drill lines with drill holes spaced 50m apart which was of insufficient resolution to make a discovery.
Methodology: Data used in the MRE is largely based on down-hole radiometric gamma logging taken by a fully calibrated Aus Log gamma logging system which was used in the recent and previous drilling programs. Down-hole gamma readings were taken at 5cm intervals and deconvolved into equivalent uranium values (eU3O8) before being combined to 1m intervals. Geochemical assays were collected from 1m RC-drilling intervals, which were split to 1 to 1.5kg samples by riffle splitters. 120gm were further pulverised for use in regular XRF determinations and ICP-MS check analysis work. Selected samples from the historical holes previously were also assayed for U3O8 by ICP-MS method to confirm the XRF results. For further description of sampling techniques and associated data see Appendix 2 Table 1.
The geochemical assays were used to confirm the validity of the eU3O8 values determined by down-hole gamma probing. After validation, the eU3O8 values derived from the down-hole gamma logging were given preference over geochemical assays for the resource estimation.
The relevant drill hole details and results were previously reported by Deep Yellow in announcements made to the ASX on 19 April 2017, 22 May 2017, 22 June 2017, 11 July 2017, 27 September 2017, 14 December 2017, 17 April 2018 and 5 July 2018.
Figure 2 (see link below) shows the Tumas 3 Deposit grade thickness (GT- eU3O8ppm x metre thickness) contour map outlining extent and nature of the mineralisation over the 10km length of channel tested and includes the 3km of mineralised tributary channels. Cross-sections through the western and eastern extensions of the Tumas 3 uranium mineralisation are shown in Figures 3 and 4 (see link below) respectively.
Prospectivity, High Potential and Future Drilling
The continued drilling of the palaeochannel at Tumas 3 continues to prove highly successful, fully endorsing the new approach that has been taken to test this highly prospective area. This work keeps adding substantial new uranium resources at Tumas 3. Additionally, the investigations over the past months has also identified extensive untested palaeochannels over which high prospectivity is being confirmed.
The 31.2Mlb now attributable to Tumas 3 translates to 3Mlb/km for the 10km over which this deposit occurs. The 63.3Mlb of Inferred Mineral Resources now attained from the Reptile Project palaeochannels represent a remarkable 97.5% increase in the calcrete resource base on this project since the new investigations commenced 18 months ago. Deep Yellow is now within reach of the first major milestone of 100Mlb eU3O8. As has been previously stated, increasing the palaeochannel calcrete resource base toward the range of 100-150Mlb uranium resources in the 300 to 500ppm U3O8 grade range is regarded as a realistic objective. With Tumas 3 remaining open to the immediate west and a further 85km of palaeochannel identified still to be tested, it is not unreasonable to estimate that 15 - 20km of these channel systems will return 3 - 5Mlb/km of uranium mineralisation.
This strongly justifies the need to continue exploration and systemically drill-test the underexplored palaeochannel systems contained in the Company's 100% owned tenements, EPLs 3496 and 3497.
Drilling will resume on these targets in late July 2018.
To view tables and figures, please visit:
About Deep Yellow Limited
Deep Yellow Limited (ASX:DYL) (OTCMKTS:DYLLF) (Namibian Stock Exchange:DYL) is a specialist differentiated uranium company implementing a new 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. 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.
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Deep Yellow Limited (ASX:DYL) New Discovery East of Tumas 1 Deposit Introducing Significant Additional Resource Upside