Location

The Nyang Project comprises 3 granted Exploration Licences (E08/1644-46) and one application, for a total current granted area of 1,347km². It is located some 960km north-northwest of Perth and approximately 150km southeast of the coastal town of Exmouth.

The climate is arid sub-tropical with intermittent stream flow including major flood events related to cyclonic rainfall. The tenements lie in marginal pastoral country with no permanent habitation except station homesteads. Open to dense mulga scrub dominates, with some eucalyptus stands along drainages.

Topography is subdued with small mesas and buttes capped by resistant laterite and silcrete. These are interspersed with wide flood plain sediments related to the braided channels of the Lyndon River, with aeolian sands including dunefields occurring on the western side of the tenements.

Project Geology and Exploration History

The Nyang Project is located along the north-eastern margin of the Carnarvon Basin where basin sediments unconformably overlie Precambrian basement of the Gascoyne Province. The basement consists of Proterozoic granites, and metamorphic gneisses and schists. The margin of this basement is block faulted, mostly along north-south trending structures. On the western side of the Project area the Proterozoic complex deepens, due to the block faulting with a system of horst and grabens. The basin subsequently is overlain by sediments of the retaceous Winning group which consists of Birdrong Sandstone, Muderong Shale, Windalia Radiolarite and Gearle Siltstone. Late tertiary and quaternary laterite and silcrete overlay these cretaceous units and form resistant caps on mesas and buttes. Stratigraphically older than the cretaceous units are Devonian limestones, sandstones and mudstones that outcrop over small areas along the eastern side of the project area. 

The main host unit for uranium mineralisation throughout the project area is the Birdrong Sandstone, of the cretaceous Winning group. The cretaceous units are locally thickened in palaeochannels which incise into Devonian limestones, sandstones and mudstones or into the Proterozoic basement. Uranium mineralisation is associated with “red-ox” boundaries within the permeable units (Figure 2). These zones are marked visually by the disappearance of pyrite in dark grey sediments, which is replaced by hematite and goethite in brown to white oxidized zones. They are caused by progressive oxidation of the sediment due to the passage through the aquifer of oxidized groundwater. Some of these deposits are called “roll-front” deposits.

Figure 2. Carley Bore (Nyang Project). Drill spoil pile showing colour changes down through profile due to multiple red-ox zones (LYAC081 7399800N 295100E)

Minatome Australia Pty Ltd (later in joint venture agreement with Urangesellschaft Australia Ltd and Aquitane Australia Minerals Pty Ltd) began exploration in the area in September 1978. Total Mining Australia Pty Ltd continued this exploration until 1984. The main objective of the exploration program was to define the extent of the Birdrong Sandstone and to locate red-ox boundaries within it, with which roll-front mineralisation might be associated. Programs completed included regional aeromagnetics, a gravity survey, and drilling of rotary mud holes and a single diamond drill hole LYN-D-37 (7399490N 295470E) at Carley Bore. LYN-D-37 intersected finely disseminated uranium mineralisation at a depth of approximately 60m, and returned results ranging up to 0.9m at 2,360ppm U3O8 in the Birdrong Sandstone close to a red-ox boundary. Following these encouraging results no further drilling was completed and the tenements were relinquished in 1985.

In 2006 Carbon Energy acquired the tenements and completed the following work programs:

• Compiled and spatially located all historical exploration data;
• Completed approximately 1,030 line km of airborne EM (AEM) on 200m and 400m line spacing, and processed and interpreted all acquired data;
• Completed a program of regional groundwater sampling;
• Compiled and interpreted aeromagnetic and radiometric data from recent geophysical surveys undertaken by the Geological Survey of Western Australia;
• During 2007-08 completed a total of 119 aircore holes for 9,111m; and
• Completed a detailed ground gravity geophysical program on 200m x 50m centres covering an area of 16km2.

The results of these programs have produced encouraging results over a strike length of 3km at Carley Bore prospect in a palaeochannel near the Lyndon River (Figures 3 and 4). This mineralisation remains open along strike to the, south. It is associated with red-ox boundaries (shown by a variation from oxidized goethite-hematite sediments to grey sediments containing sparse fresh pyrite and organic material). As such, it has the characteristics of a roll-front deposit but at this stage the geometry of the oxidation boundaries is not known.

A selection of significant intersections from the two programmes is listed in Table 1.

Figure 3. Location of Mineralised Aircore Holes – Carley Bore prospect, Nyang Project – Showing indicative contours of U3O8 values returned from geochemical analysis.

 Table 1. Carley Bore prospect, Nyang uranium Project significant drilling results from 2007 and 2008 aircore drilling programs. (U3O8 assays by SGS laboratory, ICP-MS after 4-acid digest, with detection limit 0.05ppm U)

Note: Mineralised intervals are calculated as the cumulative total of U3O8 divided by the total down-hole intercept (metres).  A maximum internal dilution of 1m of less than 100ppm U3O8 has been permitted so long as the cumulative intersection exceeds 100ppm U3O8. All holes are vertical.

Figure 4. Cross section 7400040N – Carley Bore prospect, Nyang Project

The detailed gravity survey has shown the palaeochannel extending over a total strike length of at least 10km (Figure 5).

Figure 5. Residual gravity image from detailed ground survey - showing palaeochannel and area of Carley Bore drilling, Nyang Project