In addition to its flagship Omahola Project, the Tubas Sand Project and the Shiyela Iron Project, RUN’s EPLs also contain palaeochannel deposits within an extensive, highly prospective palaeochannel system developed over some 80 kilometres (Figure 1).
These palaeochannel uranium deposits, made up of the Tumas, Tubas Calcrete and Aussinanis deposits have a combined JORC Mineral Resource of 56.8 Mt at 288 ppm U3O8 for 16,384 tonnes – 36.0 Mlbs U3O8.
Figure 1: Digital Elevation Model overlain by U2/Th anomalies showing outline of JORC Mineral Resources at Tubas Sand, Tubas Calcrete, Tumas and Aussinanis
The palaeochannel deposits contain secondary uranium mineralisation (carnotite) hosted predominantly by fluviatile sheetwash sands and gravels with some deeper incised palaeochannel development.
It is envisaged that these shallow resources will be mostly free digging with some drill and blast sections, allowing for cost effective mining. Ore would most likely be treated in an alkali plant (as per the Langer Heinrich deposit).
The current Tubas-Tumas Palaeochannel JORC Mineral Resources totals 22.2 Mt at 369 ppm U3O8 for 8,181 tonnes – 18.0 Mlbs U3O8 (Table 1).
The palaeochannel systems within RUN’s tenements, aggregate 80 kilometres of prospective channel with JORC Mineral Resources established at Tubas Calcrete (2012), Tumas (2009 and 2010) and Aussinanis (2010). RC drilling of the Tumas-3 sector of the palaeochannel over 25 kilometres on wide spaced regional lines outlined a potential target in the range of 10 to 30 Mt at a grade of 300 to 400 ppm U3O8 at 200 ppm cut-off.
Figure 2: Tubas-Tumas Palaeochannel Drilling on AEM Survey Image
Geomine Consulting Namibia CC (ASX 28 February 2012) provided the Company with an Inferred Mineral Resource estimate (reported to JORC Code standard) for the Tubas Palaeochannel which includes the Tubas Sand deposit. The estimate is based on the historical data reported by Anglo American Prospecting Services (Anglo) from work undertaken on the deposit during the 1970’s and early 1980’s. Anglo also undertook a feasibility study during that period.
The 2012 Inferred Mineral Resource for the Tubas Palaeochannel totalled 99.3 Mt at 162 ppm U3O8 for 16,087 tonnes – 35.5 Mlbs U3O8 at 70 ppm U3O8 cut-off. An Inferred Mineral Resource to JORC Standard has also been determined for the portion of the Tubas Sand deposit that falls within the Tubas Palaeochannel. This resource (Tubas Sand) totals 87 Mt at 148 ppm U3O8 for 12,876 tonnes – 28.4 Mlbs U3O8 at a 70 ppm cut-off and is the carnotite bearing red sand that is amenable to upgrading via physical beneficiation in a Schauenburg Hydrocyclone plant.
The balance of the Tubas resource is classified as Non-Schauenburg material is more typically a calcrete-hosted style of mineralisation which has been reclassified at 100 ppm cut-off (Table 1) and included in the JORC Summary designated as Tubas Calcrete with the near-by Tumas palaeochannel deposit. This is in line with DYL’s standard criteria that set a minimum economic grade for calcretes at around 300 ppm U3O8.
In October 2010, Hellman & Schofield Pty Ltd (H&S) provided the Company with a JORC Indicated and Inferred JORC Mineral Resource estimate for the Tumas deposit totalling 14.8 Mt at 366 ppm U3O8 for 5,414 tonnes or 11.9 Mlbs U3O8 at a cut-off grade of 200 ppm U3O8.
Tumas mineralisation occurs as secondary carnotite enrichment of a variably calcretised palaeochannel and sheetwash sediments and adjacent weathered bedrock. The Tumas deposit has a strike length of approximately 16 kilometres with an average width of around 400 metres and extends to a maximum depth of 47 metres (Figure 1).
The Tumas-3 area drill data was also evaluated by H&S but due to broadly and irregularly spaced lines of drillholes, the mineralisation was determined to be too poorly defined for inclusion in the resource estimates. However when combined with geophysical survey results, the Tumas-3 drill results provide an indication of the orientation and extent of the mineralised zone. Consequently a conceptual exploration target range of 10 to 30 Mt at a grade of 300 to 400 ppm U3O8 at 200 ppm cut-off has been estimated for Tumas-3, although it is uncertain if future exploration will result in the determination of a Mineral Resource over the entire Tumas-3 channel system.
In November 2010 drilling at the Oryx Prospect within the Tumas-3 palaeochannel identified high-grade uranium mineralised red sand adjacent to the main channel similar to the Tubas Sand deposit material (Figure 2), as well as additional high-grade mineralisation within the palaeochannel.
RC drillhole ORXR37 intercepted:
• 8 metres at 516 ppm U3O8 from 5 metres depth
ORXR37 is located approximately 20 km east of the Tubas Sand deposit and demonstrates that mineralised red sand is not restricted to a single area of the palaeochannel system. (Figure 2)
Infill drilling within the palaeochannel at Oryx also outlined additional high-grade mineralisation (XRF chemical assays) with selected intercepts of:
• 8 metres at 614 ppm U3O8 from 7 metres
• 11 metres at 1,097 ppm U3O8 from 5 metres
• 7 metres at 782 ppm U3O8 from 3 metres
The Aussinanis Project is located within EPL 3498 approximately 100 kilometres SSE of Swakopmund. In May 2010 H&S completed a Mineral Resource estimate for Aussinanis comprising Indicated and Inferred resources reported in accordance with the JORC Code for a total of 34.6 Mt at 237 ppm U3O8 for 8,203 tonnes 18.1 Mlbs U3O8 at cut-off grade of 150 ppm U3O8.
Table 2: Aussinanis JORC Mineral Resource Estimates Summary – June 2011
Mineralisation occurs as secondary carnotite enrichment of a variably calcretised palaeochannel and sheetwash sediments and adjacent weathered bedrock within a northeast trending zone approximately 29 kilometres in length (Figure 4). The mineralisation commonly outcrops but is generally overlain by an average thickness 1.7 metres of poorly mineralised material. The mineralised sand ranges in thickness from 1 to 19 metres and averages approximately 4.4 metres.
The fine grained wind-blown mineralised sand deposit known as Tubas Sand, which is associated with the Tubas-Tumas palaeochannel, was recently subjected to hydrocyclone beneficiation testwork which successfully upgraded the uranium content of the sand by a factor of 6.9 into 12% of the mass at 84% recovery resulting in a significant boost to the economics of the deposit. This process may have wider application across other deposits in the region, including Aussinanis.
The area has been rehabilitated and its future development is being discussed with interested parties.
Deep Yellow announced it had executed a Heads of Agreement (HOA) with the Epangelo Mining Company (Pty) Ltd (Epangelo) to progress the Aussinanis Project on 22 January 2013. Epangelo is a private company with the Government of the Republic of Namibia as its sole shareholder, established to ensure national participation in the discovery, exploitation and beneficiation of Namibia’s mineral resources. It aims to develop a portfolio of high quality assets and services for the benefit of its stakeholders.
The Aussinanis and Ripnes tenements (EPLs 3498 and 3499) were transferred into a newly established company, Yellow Dune Uranium Resources (Pty) Ltd (Yellow Dune). Epangelo has acquired an initial 5% of Yellow Dune to fund testwork to demonstrate that the Aussinanis deposit can be upgraded by physical beneficiation.
The shareholding of Yellow Dune is initially RUN 85%, Epangelo 5% and RUN’s empowerment partner, Oponona Investments (Pty) Ltd (Oponona) 10%. Assuming the initial phase of testwork is successful, Epangelo will become the operator of the joint venture and would earn up to 70% in Yellow Dune by funding a pre-feasibility and bankable feasibility study. RUN and Oponona will at that stage hold 20% and 10% respectively, with the terms and conditions of Oponona’s participation reflecting those of its existing agreement with RUN.