Venus Metals has identified some high-priority drill targets for clay-hosted and fresh rock rare earths mineralisation at its wholly-owned Marvel Loch East project in WA. High resolution 50m line spaced aeromagnetic survey results have delineated demagnetised zones possibly indicative of deep weathering of the previously-identified rare earth element-enriched monzogranite leading to clay-hosted rare earths deposits.
Hard rock rare earths targets were identified within a 25km long magnetic trend and a 2.5km by 3km zoned magnetic anomaly.
The zoned magnetic anomaly has a strong magnetic aureole surrounding a non-magnetic core that has limited monzogranite rock outcrop present. The company says the arcuate and ovoid magnetic highs within granite terrain are suggestive of a regional scale magnetite-bearing monzogranite that is enriched in rare earth elements. The monzogranite outcrop has previously returned total rare earths results up to 4365 parts per million.
A detailed radiometric survey was also undertaken. Previous soil sampling programs returned up to 6092ppm total rare earth oxides.
The most prominent magnetic high is a north-east trending lenticular anomaly about 700m in width, which can be traced semi-continuously over a 25km strike length. The southern and northern ends of the magnetic high correspond to outcropping monzogranite anomalous in rare earths and potassium. The strong magnetic signal reflects the mineral magnetite, according to the company. Additionally, sixteen potassium anomalies have been defined, further targeting outcropping monzogranite REE mineralisation.
Venus has sampled historical drill spoil and assays over 3000ppm total rare earths were returned from clay samples. A detailed study of the monzogranite bedrock identified weathering and the release of rare earths from the host mineral allanite, which the company deemed favourable for the formation of clay-hosted rare earths. Ten clay samples from the historical drill spoil have been submitted for diagnostic metallurgical tests. Acid leachability tests are critical to understanding the potential recovery economics of clay-hosted rare earths. Some rare earths are locked in minerals that are not easy to leach, seriously affecting recovery and Venus is being prudent in ensuring its clay-hosted rare earths have the right characteristics.
Laboratory studies have shown the primary magmatic rare earths mineral present in the monzogranite is allanite. Release of rare earths from the allanite primary host during weathering is deemed favourable for the formation of rare earths-enriched clays.
Venus has an extensive program planned including air-core drilling that will target demagnetised zones along regional magnetic highs to explore for clay-hosted rare earths deposits in the residual weathered zone. RC drilling will target bedrock monzogranite rare earths mineralisation. Soil and rock chip sampling will test new radiometric anomalies.
The company has applied for the WA Government’s exploration incentive scheme grant payments to assist with drilling costs.
The overlay of magnetic and radiometric anomalies, known geology, soil and rock chip samples with elevated rare earths leads to compelling hard rock drill targets for Venus. The demagnetised zones present similarly attractive clay-hosted targets. One to watch.
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By Matt Birney
