On Tuesday, ECR Minerals (LSE:ECR) announced that processing and interpretation of airborne geophysics data has completed for its Windidda gold project in the Yilgarn region of Western Australia. The development marks a crucial step towards determining drill targets and assessing the potential for gold mineralisation at the asset, which is made up of nine licences covering 1,600km2 of ground.
The geophysics work, completed by Western Geophysics on behalf of ECR, aimed to determine the depth of Archaean units below overlying sediments at Windidda. Modelling showed that depths to magnetic sources are shallowest on the magnetic trend strike north-north-west to south-south-east in the western half of the project. In some areas, magnetic units were indicated at depths of fewer than 200m. Ahead of future exploration or drilling, ECR said that additional geophysics surveys are recommended to reduce risk further at Windidda
Previous work was completed c.7km to the south of the southern boundary of Windidda exploration licence application E38-3369 by mining firm North at its Bermuda project area between 1998 and 2000. North concluded:
‘Significant gold anomalism has been intersected within E38/589. Associated with anomalous gold values are strong alteration zones, major through-going structures and anomalous multi-element geochemistry. All these factors show that E38/589 exhibits significant potential for hosting gold mineralisation and, requires further drilling to test anomalous zones.’
ECR said that the Bermuda trend projects into Windidda exploration licence application E38-3369, with modelling results indicating ‘feasible drill targets’ in the area.
ECR applied for the Windidda licences in January, and this process is ongoing. The Yilgarn Craton, on which Windidda sits, is host to around 30pc of the world’s known gold reserves and has been explored for over a century. Thanks to its position as Australia’s premier mineral province, the area attracts more than half of the country’s mineral exploration expenditure and produces around two-thirds of all of its mined gold. Beyond gold, the region also contains some 20pc of the world’s nickel reserves, 80pc of its tantalum assets, and vast amounts of copper and zinc.
Location of ECR’s Windidda licence applications (Source: ECR Minerals)
Much of the Yilgarn Craton, and Western Australian for that matter, is made up of what are known as Archaean greenstone belts- formed during the early stage of earth’s development. Importantly, these formations – which can also be found in Eastern Canada and South Africa – often contain vast supplies of gold as well as other metals such as silver, copper, zinc, and lead.
Thanks to its location and encouraging geophysics, ECR has identified the Windidda as a potential greenstone-hosted orogenic gold exploration opportunity. It believes it has significant potential to contain Archaean greenstones buried beneath cover. Speaking to ValueTheMarkets, ECR’s chief executive Craig Brown elaborated on this point.
‘The results of the study by Western Geophysics are most encouraging and demonstrate real potential for the discovery of gold mineralisation hosted in under-cover Archaean greenstones in the world-class gold mining environment of Western Australia. The under-cover greenstone exploration model has been successfully tested to date by Greatland Gold at its Ernest Giles project located approximately 125km east of ECR’s Windidda gold project.
‘Nearly a third of the world’s gold reserves are contained within the Yilgarn Craton, and the Yilgarn Craton only covers a part of Western Australia. The majority of all gold deposits within both Western Australia and the Yilgarn Craton are contained within Greenstone belts, so it is very promising that the geophysics shows that some of those magnetic targets are only 50-150m deep, which is very shallow.’
Tuesday’s update comes as ECR continues its new approach to sampling for gold at its Creswick project in Victoria, Australia. Following a technical review earlier this year, the business confirmed that the Victoria-based project’s mineralisation is ‘nuggety’ in nature. This meant that the firm’s assay results to date from the project, which were completed using ‘part-of-bag’ sampling techniques, may have understated its gold potential considerably.
To rectify this, ECR devised a new ‘whole-of-bag’ sampling technique called gravity concentration that it has now begun reapplying to all of the samples it has collected to date. At the time, the organisation’s chief executive Craig Brown said that this new approach could be ‘company transformational’, leading ECR’s share to soar to 1.23p.
In an August update, ECR said that, following delays stemming from poor winter weather in Victoria, it had established a testing process fully. This uses the dual methods of gravity and chargeability and is capable of removing coarse, fine and ultrafine particles of gold from the RC samples. ECR said that, while the process adds time to the testing period for each bag, it is essential for reliable data collection.
The process is now beginning to yield results from samples taken from the quartz zones around the higher grade results from holes CSR006 and CSR012 and a single bag from CSR010. The CSR006 sample from 15-16 m has been upgraded from 44.63 g/t to 63.03 g/t. Of this gold, 50pc was in the tails indicating there is a significant component of very fine gold with the nuggets) Meanwhile, ECR said it recorded further gold content upgrades in most bags processed along with downgrades in three packs.
In the video below from Visual News Services, Brown explains why he is confident that ECR’s new sampling method will continue to yield gold upgrades at Creswick over coming months.