The Project is located within the Yalgoo-Singleton greenstone belt of the Murchison Domain, to the west of the Ida Fault in the Archean-aged Yilgarn Craton of Western Australia. The north-northwest trending Yalgoo-Singleton greenstone belt is bound to the north, east and west by granitic rocks, which are dominated by biotite monzogranite. This greenstone belt consists of basal tholeiitic to komatiitic basalts that are uncomformably overlain by siliciclastic sediments, BIFs and andesites. The sequence has been intruded by late Archean mafic and ultramafic, with most occurring at the contact between the basal basalts and the sediments.
The Magnetite Iron mineralisation at the Yogi deposit is hosted within three separate amphibole-magnetite BIF units that have been interpreted over a strike length of approximately 18km. The BIFs strike northwest and dip moderately to steeply towards the west. The individual BIF units are usually separated by lenses of mafic, ultramafic and felsic volcanic. To the west of the hanging wall BIF, the sequence is dominated by the Olive Queen Gabbro and the Western Ultramafic. To the east of the footwall BIFs, the sequence is dominated by the Eastern Mafic. Several unmineralised dolerite dykes cross-cut the BIF in the central to the northern part of the deposit. Weathering has resulted in the oxidation and remobilisation of iron minerals in the upper parts of the profile. Within the BIF units, this has resulted in the conversion of magnetite to hematite and goethite. A typical cross-section through the deposit showing the main lithological units is presented in the Figures below.
The resource model has been confined to the northern half of the deposit where it is centred on the mining lease (M 59/740-I), and where it is considered that there are adequate data for the delineation of JORC-compliant Measured and Indicated Mineral Resources.
Graph of typical cross section through the Yogi deposit