Background on Australian Ilmenite Resources Pty Limited (AIR) tenements, McArthur Basin

Abstract

Australian Ilmenite Resources Pty Limited (AIR) holds several exploration licenses and exploration license applications within the Roper River region of the Northern Territory. One ML within this region has been applied for. The Roper HM project was established in 2001 as Exploration & Resource Development Pty Limited (ERD) to explore and develop the HM mineral potential of the region. On February 05th 2009 ERD changed its name to Australian Ilmenite Resources Pty Ltd (AIR). The Roper Heavy Minerals Project is confined to the Roper Group specifically targeting the ilmenite-bearing dolerite sill horizons and their erosional transport trails. The strata are generally flat lying to undulating although secondary folding and reactivation of older faults result in steepening of dips and stratigraphic dislocation in places (WNW trending Urapunga Tectonic Ridge in the central area and N-S trending Strangeways Fault in the southwest). The absence of Cambrian flood basalts and only remnant outliers of Cretaceous sandstones, both of which are extensive and surround the Project, suggest a significant exposure to uplift and erosion within the area permitting exposure of the underlying Proterozoic sediments and dolerite sills. Extensive deposits of Quaternary to Recent sediments comprising alluvium, colluvium, unconsolidated gravel and sand overlain by mud-rich soils are mapped in the project area and reflect material derived from prolonged weathering and erosion during the Tertiary. Sills of the Derim Derim Dolerite were emplaced at various stratigraphic horizons from a primary magma source at depth. Extensive lateritised outcrops, subcrops and regolithic soils of the dolerite have been mapped over approximately 1,300km2. The dolerite outcrops as low-relief medium to coarse grained, variably altered and weathered ('onion-skin' weathering) rounded boulders. Composition is dominated by plagioclase (40%), clinopyroxene (40%), amphibole (7%), opaques (ilmenite & magnetite 5%) and clay (7%). The associated regolith soils are deep red-purple-brown, clay-rich and contain abundant liberated ilmenite and locally with accessory titanomagnetite, magnetite and haematite grains. In some areas these dolerite sills have only been recently exhumed (higher elevations) and in other instances, larger areas of dolerite sills have been exposed for a longer geological time resulting in pisolitic laterite formation and attendant erosion (lower elevations). These latter areas are considered to have the best potential for higher insitu ilmenite grades in both eluvial and alluvial terrain. Diamond drillhole intercepts of the dolerite sills show a thickness in the order of 60-70 metres with upper and basal fine-grained chilled margins of 6-10m. Thin section work commissioned by Pacific Oil & Gas in the late 1980's showed the rock to be representative of a small, high-level intrusion of doleritic basic rocks. Ilmenite and magnetite are observed to be primary constituents of the dolerite. A chemical analysis (Cochrane & Edwards, 1960) of fresh dolerite within the Moroak Formation (Prk) near the Sherwin Iron Deposits reported 1.52% TiO2. The ML application is a small portion of a very large ilmenite resource where the company has applied to take a large sample (10,000 t). This is required for a Chinese company (potential JV partner) to undertake metallurgical testing for processing in China. The company was issued approval under the Mining Act for the bulk sample in May 2009 and now awaits approval from the Chinese company to proceed to extraction. Throughout the region and within tenement AIR has over 300,000 ton measured resources of ilmenite with a further 4 million ton either indicated or inferred. Work now continues on the southerly tenements where it is believed a further 5 to 12 million ton ilmenite is present in the top 1m of soils. Over 6000 auger holes have been drilled and in excess of 20,000 samples taken and analysed. AIR ilmenite is very low in deleterious minerals such as Cr2O3, U + Th and is suitable for the production of both synthetic rutile and titanium sponge.