Preliminary drilling at Northern Minerals’ Browns Range heavy rare earths project in the Kimberley region of W.A. has intersected significant mineralisation in the Gardiner sandstone, which stretches over tens of kilometres. The Gardiner was previously considered to be less prospective than the underlying Browns Range Metamorphics that host the Wolverine and Gambit West deposits.
Australia’s only heavy rare earths producer, Northern Minerals, has identified an extensive new exploration target at its Browns Range rare earths project in the Kimberley region of W.A.
The company says that significant mineralisation was intersected in the Gardiner sandstone, an overlying geological unit previously considered less prospective than the underlying Browns Range Metamorphics, which host the main Wolverine and Gambit West deposits at Browns Range.
Preliminary sampling using a portable XRF handheld machine has indicated wide, highly anomalous heavy rare earth mineralised zones with total rare earth oxide grades of up to 8%.
Both the Dazzler and Iceman prospects are located just 15km from the Browns Range pilot processing plant that started producing heavy rare earths for export last week.
The Dazzler prospect, which was partly the subject of the recent drilling campaign, is located to the south of the pilot plant on the edge of a small scarp adjacent to a strong geochemical soil anomaly.
It was previously drilled in 2013.
The current program is the first to assess the unconformity between the Gardiner sandstone and the underlying Browns Range Metamorphics.
Thirteen holes for 1,242 metres have been drilled in the current program with highly anomalous XRF readings returned in both the Gardiner sandstone and Browns Range Metamorphic units, with the higher readings in the overlying sandstone.
Northern Minerals said there is significant potential within the Browns Range project area to target the intersection of mineralising structures with the unconformity as a new exploration target.
The Iceman prospect is located about 400m along strike to the southeast of Dazzler and the recent campaign represented the first drilling to be carried out there.
Nine holes totalling 754m were drilled with anomalous XRF yttrium readings returned from several holes.
Samples from both prospects will be submitted to the laboratory, with geochemical assays expected in the next few weeks.
Follow-up drilling is planned to commence later in the September 2018 quarter, with diamond drilling likely to be included to assist with the interpretation of the structural controls on mineralisation.
Northern Minerals Managing Director George Bauk said: “I am particularly encouraged by the potential for heavy rare earth mineralisation to be discovered in the overlying Gardiner Sandstone given we have tens of kilometres of the unconformity that presents itself as a completely new exploration model.”
Browns Range is the only dysprosium and terbium heavy rare earth producing operation outside of China globally and the company is well-placed to become a significant, stable supplier of these important commodities.
Dysprosium is a key material that is used in the making of permanent industrial magnets that are used in motors for electric vehicles.
Nearly all electric vehicle permanent magnets contain some dysprosium and with EV demand expected to grow beyond 20 million vehicles annually by 2025, it is a critical material if this momentum is to continue.
The first stage of the Browns Range project is expected to run for three years with the plant producing up to 60,000 tonnes of heavy rare earth concentrate per annum.
The discovery of extensive new exploration targets at Browns Range could add substantially to the current expected mine life and turbo charge the all important NPV if they result in a significant enough mine life increase.