お知らせ • Jul 12
Empire Metals Limited Announces the Results of the First Petrographic and Mineralogical Studies on the High-Grade Titanium Discovery at the Pitfield Project Located in Western Australia
Empire Metals Limited announced the results of the first petrographic and mineralogical studies on the high-grade titanium discovery at the PitfieldProject, located in Western Australia, which confirm the presence of ilmenite, an important economic titanium-iron oxide mineral. Mineralogical Assessment As part of the petrographic study, an initial mineralogical assessment report was carried out on samples of RC drilling chips taken from four drill holes at Pitfield. Of these, three were drilled at Mt Scratch in the northern part of the tenement and the other hole was the most southern hole drilled on the Thomas property. The RC chip samples have all been interpreted to be weakly metamorphosed sedimentary rocks (siltstones, sandstones and conglomerates) containing quartz and feldspar as the dominant components. All the samples contain various amounts of iron oxides, iron-titanium oxides, chlorite, muscovite, epidote and carbonate with minor to trace amounts of rutile, leucoxene, chalcopyrite, apatite and tourmaline. Importantly from an economic perspective, the dominant iron and titanium oxide minerals, are hematite (Fe2O3) and ilmenite (FeTiO3), with lesser rutile and leucoxene, also titanium oxide minerals. Most importantly, only minor magnetite (Fe3O4) was identified within the samples. There is evidence of some trace amounts of titanomagnetite, but the vast majority of the iron oxide and iron-titanium oxide minerals are hematite and ilmenite respectively. This has significant economic implications as titanomagnetite can be very difficult to process, unlike hemo-ilmenite which is currently processed by Rio Tinto at its 70-year-old RTIT Quebec Operations in Quebec, Canada. Additional sampling and detailed mineralogical work is needed to determine if hemo-ilmenite is an important mineral at Pitfield. The petrographic study clearly supports field evidence indicating that the iron-titanium mineralisation at Pitfield is hydrothermal in origin and hosted by altered, clastic sedimentary rocks, and so is neither a palaeoplacer Heavy Mineral ('HM') Sands type deposit nor an igneous intrusive-hosted "hard-rock" type titanium deposit. Pitfield appears to belong to a new class of soft sedimentary rock type titanium deposits that are stratabound and hosted within a layered succession of clastic sedimentary beds. 3D Magnetics Model A 3-Dimensional Magnetic Susceptibility Inversion ("MSI") model has been created utilising the data from the regional magnetics survey carried out historically by the Geological Survey of Western Australia (GSWA). A threshold magnetic susceptibility value of 0.005 SI was used to create the MSI isoshell shown in red in Figures 2 and 3, which encapsulates magnetic susceptibility values ranging up to 6.6552 SI. The model highlights the depth extent and continuity of the 30km long core body of this massive regional magnetics anomaly at Pitfield, mapping the depth to at least 6km below surface, the extent to which the data has been modelled. From a geological viewpoint the magnetics model closely matches the interpreted structure and stratigraphy at Pitfield, where deep, northwest striking, sub-vertical structures define the sharp, western margin of the Yandanooka Basin and 50-80° easterly dipping strata define the eastern side of the Basin, Historical surface sediment sampling (stream sediments, soil and auger samples) byConzinc Riotinto of Australia ('CRA') shows TiO2 enrichment (greater than 1% TiO2) over virtually the entire 40km length of the regional magnetics anomaly. The areaof potential high-grade TiO2 mineralisation, confirmed by drilling in the immediate vicinity of Mt Scratch, has been extended from 3km2 to more than 50km2. There is also, potentially, a similar high-grade area (covering 50km2) to the east of the historical Baxter's Mine, lying 20km south of Mt Scratch.These large TiO2 enriched areas are both completely open to other parts of the 40km by 8km magnetics anomaly. Mineral Sands History in the Region Whilst the Pitfield titanium discovery is not a palaeoplacer HM Sands deposit, there are multiple known HM Sands resources within the Eneabba Region of the Perth Basin, some lying alongside the Western margin of the Yandanooka Basin. In August 2011, Sheffield Resources announced a maiden Resource estimate for the Yandanooka HM Sands project, which lies a few kilometres west of the Pitfield tenements, of 1.84 million tonnes of contained heavy mineral (71.75Mt @ 2.6% HM in Indicated and Inferred categories). The Yandanooka deposit was previously explored by RGC Ltd. during the late 1980s and by Iluka Resources Ltd. between 2003 and 2006. Both companies completed broadly spaced drill traverses across the deposit. The deposit is 5km long by 1.7km wide, between 2m and 20m thick, and is interpreted to be a dunal-style HM Sands deposit situated along an Eocene palaeo-shoreline. Given the HM deposit's close proximity there is considerable likelihood that the titanium bearing minerals, specifically the ilmenite and rutile, were sourced through westward erosion of the primary stratabound titanium deposit at Pitfield. Previous mineral assemblage work carried out initially by Iluka Resources and subsequently by Sheffield, identified high-quality ilmenite (>55% TiO2) and rutile (>95% TiO2) which augurs well for the quality of the titanium mineralisation at Pitfield. Future Work The maiden drill campaign consisted of only 21 RC drill holes totaling 3,206 metres, with the first 18 holes focused near the old Mt Scratch workings to the north and the final three holes spread evenly across a 30km distance to the south. Future drill programmes, including both diamond core and additional RC drilling, will be carried out along the entire length of the magnetics anomaly to confirm the scale of this giant, titanium-enriched mineral system and to also understand the distribution of key factors better, such as grade, mineralogy, thickness and extent of mineralised beds and controls on high-grade TiO2 mineralisation. Future mapping, geophysics (including airborne gravity and additional IP/resistivity) and geochemical sampling will focus on defining the structural and stratigraphic architecture of the Yandanooka Basin and which parts of this giant mineral system are most prospective for follow up drill testing.
