Dateline Resources has combined a high-powered series of multiple geology surveys to zero in on two compelling carbonatite-hosted rare earth targets at its Colosseum project in the US state of California.
An impressive suite of high-resolution datasets from geophysical, geological and geochemical surveys has provided a comprehensive view of the project. The company is now using the valuable insights gained from the potentially game-changing combo to charge into a drilling campaign at the two prospective zones.
Previous gravity, induced-polarisation (IP), magneto-tellurics (MT), airborne magnetics and radiometric surveys were interpreted in conjunction with geological mapping, recent geochemical data and historic surface sampling, to form a whizz-bang combination of data that has produced stunning clarity in understanding the project’s geological profile.
A twelve-hole diamond drilling program will now be unleashed to hammer into the company’s two targets, the Clark Mountain Fault Zone and Eastern Gravity. The drilling will test both prospects from multiple angles and a range of depths.
Plans are for several holes at depths beyond 750m to reach the rocks responsible for the geophysical signals. At Target 1, the holes will be drilled deeper and closer to the perceived centre of the system, as it is believed the rare earths-bearing rock widens with increasing depth.
Target 2 will see the drill bit punched down deep to test buried rock identified from the gravity and IP-MT surveys on the eastern side of its ground. The zone has never been tested previously with drilling.
Dateline’s primary target is known as Target 1, interpreted as a northwest bearing structure about 1.2 kilometres long and between 150 metres and 200m wide and follows along the Clark Mountain Fault Zone.
The company says the converging datasets make this target numero uno, due to a series of coincident anomalies. The IP and MT surveys indicated the presence of conductive material at depth along the fault, with radiometrics returning several elements commonly enriched near carbonatite bodies. The gravity survey also revealed high-density rock at a depth consistent with carbonatite intrusion and the geochemistry spat out elevated levels of anomalous minerals, which bear all the hallmarks of a carbonatite-related mineral system.
Target two is the Eastern Gravity prospect, defined by a strong gravity anomaly on the eastern side of the site and is a ring-like structure running north to south. The company says the target sits west of significant mantle-derived outcropping, along with a geochemical carbonatite anomaly at surface.
As a potential ace up its sleeve, Dateline has identified a third-priority target known as 2200N Anomaly, defined by broad coincident responses in its IP and MT surveys. The company intends to complete further modelling to optimise drill planning, prior to launching into a drilling program.
Dateline has also delivered a key breakthrough, with a recent drillhole plunging into anomalous subsurface rare earths on the margin of its primary target at the Clark Mountain Fault Zone. Rare earths were confirmed downhole at about 40m depth, marking the first time they have been identified at any depth at the site.
Dateline Resources managing director Stephen Baghdadi said: “The completion of the integrated high-resolution datasets has given us a level of confidence in our targeting that we have not had before. Two well-defined targets, twelve holes, and a third zone in the 2200N anomaly that we are continuing to work on. We are advancing this project methodically and the technical foundations are strong.”
Management believes the rare earths signature identified is mantle-derived and comparable to MP Materials’ groundbreaking Mountain Pass carbonatite system.
The carbonatite-style geochemical signature kicked up a slew of anomalies, returning elevated levels of barium, strontium, calcium, phosphorus, thorium and uranium, in addition to associated potassium-rich alteration in surrounding rock.
Management says the combination of elements is a widely recognised geochemical fingerprint of major carbonatite systems worldwide and believes it confirms proximity to an alkaline-carbonatite source.
Mountain Pass, 10 kilometres to the south of Colosseum, is the only operational rare earths mining and processing site in the US and accounts for about 15 per cent of global production. Both projects are within the Walker Lane geological corridor, with Colosseum sitting along strike from Mountain Pass.
In addition to the rare earths potential at Colosseum, Dateline has a firm grasp on its JORC-2012-compliant gold resource of 27.1 million tonnes grading 1.26 grams per tonne (g/t) gold for a noteworthy 1.1 million ounces.
A previous scoping study released in May last year outlined a potentially solid mining operation, projecting production of 635,000 ounces over an initial eight years, with net revenues of US$827 million (A$1.245 billion) and an internal rate of return (IRR) of 61 per cent.
The study was based on a gold price of US$2900 (A$4340) per ounce – a figure blown out of the water in recent times, given the significant move past US$5000 (A$7060) this year, currently standing at US$5180.
With the ultimate truth sayer - the drill-bit - to soon be unleashed at Colosseum, Dateline will be hoping for results that can put a similar shine from its gold resource onto the company’s rare earths fortunes.
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By Craig Nolan
