The Mount Padbury Project covers a relatively unexplored area of the Murchison Mineral Field where uranium mineralisation has been found in calcrete deposits developed within intermittently flowing tributaries of the Murchison and Talga Rivers.
The Mount Padbury Project comprises Exploration Licences E51/1147 and E51/1150 and is located near the town of Meekatharra, WA about 700 km north of Perth. Access to Mount Padbury tenements from Meekatharra is by way of the Meekatharra-Mount Clere Road, which passes from south to north through the centre of the area.
Regional Geology
The regional geological setting of the Mount Padbury Project area comprises the contact zone between the Archaean Yilgarn Craton, with the Paleoproterozoic Bryah Group rock sequence to the north. This contact trends south easterly through the northern part of E51/1150.
The north western part of the Yilgarn Craton, which forms the basement to these Paleoproterozoic rocks, is composed of the Murchison and Narryer Terranes. The Murchison terrain, which mostly underlies the Mount Padbury Project, consists mainly of "hot" (radioactive) granitic intrusives into greenstone remnants.
The Narryer Terrane, to the north, contains extensive remnants of old cratonic granitic gneisses inter-leaved with younger Archaean subcrustal rocks and late Archaean granitoids intrusives.
Project Geology
The geological setting of the Mount Padbury Project is made up of an extensive cover of quaternary-aged alluvium, sheet-wash deposits of clay, silt, sand and colluvium within an extensive south westerly draining system of intermittently flowing drainages.
Within these watercourses there are irregular areas of calcrete. Underlying these surficial deposits is a radioactive biotite monzogranite which is present within most of the northern tenement, E51/1150. This granite is intruded by generally east-west trending Proterozoic-aged dolerite dykes. To the west of E51/1150 there is a 3km thick succession of mafic to ultramafic and felsic volcanic rocks of the Mount Maitland Greenstone Belt.
In the northern part of E51/1147, there are small outcrops of Proterozoic sandy and silty sediments.
Carnotite mineralisation in the area is exposed in two shire quarries; Discovery Pit 1 and Discovery Pit 2. Carnotite mineralisation in Discovery Pit 1 occurs over an area of some 1,200m², while in Discovery Pit 2 it occurs over a 250m X 75m area in a shear developed in granite.
Both pits are within a few kilometres distance and lie to the east and west of the Meekatharra-Mount Clere Road. Mount Padbury carnotite uranium discovery is hosted within surficial sediments and overlying calcrete developed within the fossil drainage profile of the tributary system of Murchison River.
This dendritic fossil drainage system overlies deeply eroded Late Archaean granitic basement rocks. The catchment area includes "hot" radiometric granitic intrusives giving the prospect a geologic setting bearing considerable similarities to the "Yeelirrie-type valley calcrete uranium deposit".
Mount Padbury Recent Exploration Work
Exploration 2007-2008
The style of uranium mineralisation observed in the Project area and the hardpan covering the known mineralisation, makes a normal uranium exploration approach (airborne radiometric survey followed by drilling) difficult. Moreover, rock exposures within the Project area are poor; being less than 1% over much of the area.
The Project area falls in the Wajarri Yamatji indigenous heritage area. To advance exploration work further, several attempts were made to meet with the Wajarri Yamatji Working Group (WYWG) during the report period to plan a Heritage Survey over a 4km2 area at E51/1147, with Discovery Pit 1 in the centre (Plate 14).
This survey is deemed essential for planning exploration activities (drilling, trenching, rock chip sampling, etc.) in the area.
Outlook
The presence of shear hosted carnotite mineralisation suggests that there may be other setting(s) in the Project area that may contribute to an increase in the project's potential prospectivity. Accordingly, over the Heritage Surveyed area an on-ground radiometric survey (with reading on a 100m by 50m pattern) for the concentration and trends of Potassium (K), Uranium (U) and Thorium (Th), using a hand held scintillometer is planned.
After locating the broader outline of uranium anomalies in the surveyed area, detailed studies on different scales to narrow down the areas for drilling will be carried out, and the targeted areas will be drill tested.
There are also gold targets in the area as marked on the geology map.