Drilling at Mitre Hill has delivered an initial 21 million tonnes grading 767 parts per million total rare earth oxide, containing 278ppm critical REO, 226ppm heavy REO and 541ppm light REO.
In terms of grade, it is in line with its more advanced neighbour,
Australian Rare Earths, which has a total resource of 81Mt at 785ppm TREO across the border at Koppamurra in South Australia.
Resource Base's drilling has been confined to a single exploration licence, which also comes with a new exploration target suggesting the permit could host a further 13-34Mt grading 630-830ppm TREO.
Non-executive chair Maurice Feilich said further drilling could rapidly convert the target into additional "robust" resources.
Additionally, drilling on another lease 6km to the east has been completed, and while not yet resource ready, has offered higher grades up to 2447ppm TREO with assays such as 2m at 2010ppm and 4m at 1142ppm.
Feilich said the initial resource could be used to move Mitre Hill into economic, technical and metallurgical studies.
Australian Rare Earths' test work is more advanced, and has produced a rare earth carbonate from a trial pit at Koppamurra, suggesting Resource Base should be able to replicate the flow sheet, assuming the clays of the Murray Basin are similar in mineralogy.
Resource Base claims to have a
dominant land position in the southern margin of the Murray Basin with some 7022sq.km now under tenement or applications.
The explorer ended 2022 with cash of A$1.35 million following a placement to raise $750,000 at 7.5c in October.
Resource Base shares were up 20% this morning at 12c, valuing the company at $8 million.
It has traded in the range of 7.8-30c over the past year.