Dateline Resources has sparked fresh excitement after unveiling geophysical results from its Colosseum gold and rare earths project in California that closely resemble the signatures of the world-class Mountain Pass rare earths deposit, sitting just 10 kilometres south.
The company’s now-completed magnetotelluric (MT) geophysical survey revealed a textbook trio of anomalies – a gravity high, magnetic low and moderately resistive zone – directly beneath rare earth element-bearing fenite dykes at surface.
This is the same geophysical fingerprint that defines Mountain Pass, the western hemisphere’s largest rare earths deposit.
Adding to the intrigue, the targets sit precisely along a high-resistivity corridor that runs right through outcropping fenite and trachyte dykes, which are classic markers for carbonatite-related rare earths systems.
Mountain Pass is also hosted by a carbonatite and Dateline’s data appears to be ringing the same bell.
Management says the resemblance to Mountain Pass is striking. The survey has picked up all the right signals in the exact spot where rare earths-bearing rocks have already been mapped.
Although the preliminary 2D resistivity models have already proven invaluable in cross-checking the validity of the data, a full 3D inversion model is now underway to give the company a crystal-clear view beneath the surface.
Two groups of independent geophysics experts - one in Colorado and the other in Perth - have been engaged to generate and cross-verify the 3D models using different inversion techniques to tighten up confidence in the final interpretation.
While the initial MT survey has done its job, Dateline’s geochemical sampling program is also shaping up as a valuable piece of the exploration puzzle. About 75 per cent of a planned 1200 soil and rock samples have been collected across the Colosseum claims, with early assay results already confirming rare earths anomalies in surface samples.
Cerium, lanthanum and other key rare earths have popped up in numbers that exceed background levels, helping to support the geophysical case that the project area is home to a rare earths-rich system at depth.
The company will use all the collected data from the upcoming 3D MT survey, the soil sampling and reprocessed gravity and magnetic surveys to build what it has dubbed its stacked evidence approach.
By combining all the results, Dateline believes it can better pinpoint drill targets at the spots where everything lines up. Any location showing the triple play of a gravity high, magnetic low and moderate resistivity, especially when backed by surface rare earths signatures, will be fast-tracked for drilling.
Colosseum is already endowed with plentiful riches. The site already hosts a JORC-compliant gold resource of 27.1 million tonnes grading 1.26 grams per tonne (g/t) for 1.1 million ounces of gold.
Just last month, Dateline turned up the heat at its project by cranking its gold price assumption from US$2200 to a more realistic US$2900 (A$4450) an ounce as part of its ongoing bankable feasibility study.
The move supercharged the project’s net present value by a whopping 134 per cent, soaring to US$550 million (A$850 million), while slashing the payback period from three years to a lightning-fast 17 months.
The company now has its sights set on pulling in a hefty 635,000 ounces of gold over an 8.3-year mine life, averaging 71,000 ounces annually at a healthy grade of 1.3g/t and at a juicy 92 per cent recovery rate.
Operating costs are looking lean and mean at just US$1182 (A$1818) per ounce, with all-in sustaining costs coming in at US$1490 (A$2292), both of which sit well below the company’s revised gold price forecast.
As new layers of rare earths potential now emerge from the geophysical data, anticipation appears to be growing that Dateline could be on the cusp of a major gold-rare earths dual commodity play.
When the 3D survey has been completed and drill targets picked, all eyes are likely to be laser-focused on what treasures may be lurking beneath the dykes.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By James Pearson
