A tough winter drilling campaign in northern Tasmania has borne fruit for ABx Group with assays from its Deep Leads prospect more than tripling the lateral extent of the deposit’s high-grade rare earth elements mineralisation.
ABx has now kicked off its maiden rare earths resource estimation with the body of work expected to be completed in Q4.
One of the assay highlights was returned by a drill hole which returned an average total rare earth oxide, or “TREO”, of 2,910 parts per million, from 5m to 10m with a maximum TREO of 3,856 ppm. The so-called “super magnet” rare earths came in at 953 ppm from this hole.
Two other holes returned TREO averages of more than 3,000 ppm TREO, with lower super magnet grades.
The market liked the news with its shares closing 32 per cent higher at the end of trading.
Deep Leads is one of four ABx tenements that total 372 square kilometres in a 50km-plus corridor between Devonport and Launceston. It lies beneath a forest plantation and has been the focus of the company’s exploration efforts.
The 150 holes drilled in the winter campaign discovered rare earths mineralised intercepts over an area 7km by 4.6km
The most recent campaign was conducted during one of the harshest winters for years.
New drilling technologies were used, including push tube coring developed in conjunction with the company’s drilling contractor.
They seem to have paid off.
ABx says the new technique resulted in many holes now reaching target depths, confirming much thicker rare earths zones and collecting cores from important strata.
Results to date from the 150 holes drilled have led to the lateral extent of the mineralisation at Deep Leads being extended by 230 per cent to more than 4 square kilometres.
The assays have extended the rare earths mineralisation 6km east and 1km west of Deep Leads.
The southwest trending channel has been extended 750m westwards by a drill hole that intersected 5m thickness of ionic adsorption clay, or “IAC” rare earths mineralisation averaging 2,170 ppm TREO.
ABx says the new drilling technology will be further developed in the next drilling campaign that is due to start in October.
ABx Managing Director and CEO Dr Mark Cooksey said: “Tests on this channel mineralisation in hole DL403 confirmed that it can be easily processed at low cost with extraction rates of 50 per cent to 75 per cent under standard leach conditions — the same as used in similar Chinese IAC rare earth elements deposits.”
To the south of Deep Leads line of lode, drilling uncovered mineralisation which has excited ABx. One hole returned 6m averaging 1,435ppm TREO between 4m and 10m depth.
“This is a new style of REE mineralisation which could be thick and very extensive,” Cooksey said.
Previous high grades at Deep Leads have included 3,943 ppm TREO, part of 3 metres averaging 2,992 ppm TREO.
The highest grade from Portrush is 4,800 ppm TREO.
As to the quality of the mineralisation of the 6km corridor between Deep Leads and the Rubble Mound discovery to the east, this will be revealed when final assay results are in.
Holes in this anvil-shaped area were drilled late in the campaign and ABx is eagerly awaiting the assays — hardly surprising considering the good grades of TREO returned to its west, east and south-east.
Rare earths belie their name in that they are not particularly rare.
The key is finding the right combination of rare earths that are in high grades and easy to mine.
The most keenly sought-after rare earths are so-called “super-magnet” rare earths like neodymium and praseodymium that are necessary for electric vehicles, wind turbines, mobile phones and computers.
These are abundant at ABx’s Tasmanian deposits.
Deep Leads appears to tick the other important boxes, too.
Its mineralisation is relatively shallow, found in IAC so it can be developed quickly and at low cost and contains no “nasties” such as radioactive thorium and uranium that can complicate processing.
Besides Deep Leads and Rubble Mound, ABx’s portfolio of rare earths prospects include the Wind Break and Portrush projects 16km and 52km respectively from Deep Leads.
Previously known as Australian Bauxite, ABx is a high-tech company that creates new sources and technologies for the supply of strategic minerals.
It has bauxite interests in Queensland and a proposed aluminium smelter bath recycling project in Tasmania.
ABx says it is the first company to discover rare earth in Tasmania and the clay type of deposit is rare — the only commercial production to date occurring in China.
Although rare earths exploration is only one part of its business it has the potential to become a lucrative one if the discoveries of high-grade super magnet TREO continue flowing.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Matt Birney
