Lake Mason Uranium Project
Prime has commissioned a detailed low level radiometric/magnetic survey to be flown over its Lake Mason project area, commencing in March 2007. The objective is to define surface radiometric anomalies additional to Bolitho Bore and others for immediate follow up drill testing, and to define litho/chemical and hydrological trap sites where uranium mineralisation may have accumulated below the surface. Prime holds a 100% interest in two tenements covering some 426km2 located approximately 40km SW of BHP Billiton’s Yeelirrie calcrete uranium deposit in Western Australia, the largest calcrete deposit in the world containing 52,000t of uranium (Refer Figure 1). Prime’s tenements cover the Lake Mason drainage system and surrounding areas, which have formed over predominantly Archaean granitoids and minor greenstones. It is assumed that the Lake Mason and Yeelirrie lake systems evolved during similar climatic conditions over a similar granitoid basement, but historical records show that there has been no systematic exploration over the Lake Mason drainage system for uranium. Minor previous exploration with shallow air core drilling at the Bolitho Bore has defined pre-JORC target mineralisation of approximately 170,000kg U3O8 (374,000lbs) of uranium. This mineralisation is open to the south under the lake, and open to the west (upstream) and east (downstream). Several other areas along this defined channel are covered by either water or non-radioactive sheet-wash sands and sediments that may have obscured a radiometric response in previously flown widely spaced (200m – 400m) airborne surveys. Prime believes these areas of shallow cover offer an excellent opportunity for the discovery of additional blind (buried) or partly blind uranium mineralisation, using very detailed low level radiometric surveying. A key feature in the targeting of calcrete uranium deposits is the identification of hydrological trap sites within the palaeochannel systems. Prime has also targeted the intersection of the east-west oriented Lake Mason palaeo-channel with the north-south oriented Booylgoo Range greenstone belt, and several significant bends in the channel, as potential trap sites for uranium mineralisation.
Background The Lake Mason Project also lies 40km to the south west of the Yeelirrie Project held by BHP Billiton which is the world’s largest calcrete associated uranium deposit, with a published resource of 52,500 tonnes of uranium oxide (U3O8). At Yeelirrie, carnotite mineralisation has precipitated within valley fill calcrete aquifers in response to changes in groundwater chemistry. The Directors assume that the Lake Mason and Yeelirrie lake systems developed during similar climatic conditions over a similar granitoid basement, and hence the opportunity exists to identify substantial uranium mineralisation within the Lake Mason palaeodrainage system. This potential is supported by existing uranium channel radiometric data and some drilling undertaken by previous explorers.
Previous exploration at Lake Mason has focused on the defined radiometric anomalies within the eastern extremity and northern shore of the main Lake Mason channel within E57/591, where pre-JORC target mineralisation of approximately 1 million tonnes at an Areas of specific interest identified by the Directors following a review of geophysical data and historical data are the northern and southern margins of the entire Lake Mason drainage system. Several discrete uranium anomalies are present within areas of thin Exploration Program |
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