DevEx Resources holds 100% of the highly prospective Nabarlek Project, comprising a dominant 4,700km2 tenement package located in the Alligator Rivers Uranium Province (ARUP) in the Northern Territory, a Proterozoic mineral province which is known for its world-class uranium deposits (Figure 1). The ARUP is considered amongst the world’s most prospective for uranium mineralisation, with over 500 million pounds of uranium (U3O8) identified in mined current resources. At the heart of the project lies the historical Nabarlek Uranium Mine, considered Australia's highest-grade uranium mine with a previous production of 24 Mlbs @ 1.84% U3O8. However, the province is about more than just uranium.
Figure 1: Regional geology of the eastern Alligator River Uranium Province showing pre-mining endowment of uranium and gold deposits, and DevEx’s tenement holdings.
Multiple new uranium, and uranium-copper-gold exploration targets were identified following the completion of a comprehensive technical review of the historical pre- and post- mine exploration data covering the Nabarlek Project area, encompassing 50 years of exploration data (Figure 2). This highlights an outstanding exploration opportunity at the Company’s Arnhem Project.
Figure 2: Nabarlek Project – Uranium Prospects including the historic Nabarlek Uranium Mine. Uranium-copper-gold mineralisation has been intersected within basement rocks along both the Nabarlek Fault Zone (NW trending) and the North and Gabo Faults (NE trending) with the overlying Kombolgie Sandstone acting as a masking cap rock to mineralisation.
The targets surround the historic high-grade Nabarlek Uranium Mine within the Company’s granted Nabarlek Mining Lease and enclosing exploration tenements (Figure 2). The targets range from areas located immediately adjacent to the historic Nabarlek Uranium Mine, to drill targets further afield, located either down-plunge or along strike from previous high-grade drill intercepts.
Nabarlek South Prospect – Located 1.2km south-east of the Nabarlek Uranium Mine, the Nabarlek South Prospect lies at the intersection between two uranium-bearing fault zones, the west-dipping Nabarlek Fault, which hosts the uranium mineralisation at the Nabarlek Mine, and the north-dipping Gabo Fault (Figure 2). Drilling is planned to test a high-grade, north-plunging uranium shoot at the intersection of these two faults (Figure 3), containing high-grade intercepts such as:
NARD6017 25m @ 0.32% U3O8 from 115m
Incl. 2.0m @ 1.0% U3O8
and 3.0m @ 1.0% U3O8
Figure 3: High-grade U3O8 shoot at the intersection of the Nabarlek and Gabo Faults. View looking southwest.
Nabarlek Pit Prospect – The Nabarlek Pit environs possess compelling near-mine exploration targets along the North Fault through to the North Buffalo Prospect. Drilling is planned along the north-eastern Nabarlek Pit edge and eastward with the potential of extending the pre-existing uranium mineralisation (Figure 4).
Figure 4: Pre-mine (1972) ground radiometric survey clearly maps surface uranium mineralisation within the Nabarlek pit (mined 1980) with the majority of diamond/RC drilling angled to the south-west. A sharp north-east fault (North Fault) controls the northern extent of the uranium and a radiometric tail maps this fault east of the pit. Previous drilling has not tested for north-east orientated uranium mineralisation along this fault. The North Fault represents a high-priority target for extensions to the Nabarlek uranium mineralisation.
Prospective NW Uranium Corridors supported by Radon Track Etch Sampling - Between 1989 and 1990, an impressive 25,000 Radon Track Etch samples were collected on a 100mN x 200mE grid at Nabarlek. On the eastern side of the project area, the Radon Track Etch survey identified a cluster of priority radon anomalies oriented along several north-west structural corridors – parallel to the Nabarlek fault system (Figure 5).
Three of these anomalies (U40, U42 and Zeus) have been partially drilled by RC/diamond drilling with bedrock uranium mineralisation identified at the U40 and U42 prospects and significant copper identified at the Zeus Prospect.
Uranium-Copper-Gold Corridor: Zeus to U40 corridor – Previous drilling beneath a Radon Track Etch anomaly at the U40 Prospect intersected high-grade uranium-copper-gold-platinum group elements (PGE) mineralisation, including:
NAD7492 6m @ 7.6% U3O8, 0.7g/t Au, 2.0% Cu from 75m
NAD7493 12.3m @ 0.7% U3O8, 1.8g/t Au, 2.0% Cu from 80.4m
Incl. 4.8m @ 1.9% U3O8, 4.5g/t Au, 3.2% Cu
At the Zeus Prospect, a small programme of RC and diamond drilling targeting the Radon Track Etch Anomaly intersected broad open-ended copper sulphide mineralisation, including 18m @ 0.2% Cu from 38m (Figure 6).
Early-stage exploration, including drilling, is planned to test a uranium-copper-gold corridor from the Zeus to U40 Prospects.
Figure 5: A detailed 1989-1990 Radon Track Etch survey identified priority anomalies east of Nabarlek Uranium Mine. Drilling at three of the four anomalies have identified significant uranium at U40 and U42, with significant copper mineralisation seen at the Zeus Prospect. The KP Prospect has not been followed up and is considered a high priority target as it lies between the Gabo and North Fault and capped by the Kombolgie Sandstone.
Figure 6: Historical 1980’s Reverse Circulation drilling at the Zeus Prospect. Drilling has defined flat-lying copper mineralisation which remains open in all directions (see Figure 5). Historical RAB holes (NAB series) are also shown which were ineffective in defining the copper mineralisation.
Other similar uranium corridors exist on the Nabarlek, Gabo and North Faults, all of which appear to control the distribution of uranium mineralisation, as seen at the Overload, Coopers, North Buffalo, Black Bream and KP Prospects. All of these areas require a similar amount of exploration attention in the coming exploration program.
DevEx remains strongly leveraged to benefit in an improving uranium market.
Click here for Mine Management Plan - West Arnhem
Click here for Mine Management Plan - Nabarlek