Toro flipped by Wiluna disequilibrium
THE DRILL SERGEANT: Toro Energy (ASX: TOE) has had an independent analysis carried out on uranium samples from the company’s Wiluna uranium project in Western Australia by the Australian Nuclear Science and Technology Organisation (ANSTO).
According to Toro the analysis has highlighted levels of positive disequilibrium in three of the Wiluna deposits.
The company explained disequilibrium analysis to be a lab-based analytical technique that tests the accuracy of measuring uranium via a gamma probe compared to chemical assay.
Apparently the presence of disequilibrium can affect the interpretation of gamma measurements and subsequent uranium estimates that result.
Toro went on to say that a substantial portion of the published Mineral Resources for the Wiluna project have been based on historic samples which estimated uranium content from the results of gamma data alone.
The consequence of ANSTO’s findings, it said, is that the existing published Mineral Resources at the Wiluna uranium project could be greatly understated.
Disequilibrium of greater than 1.1 is considered by ANSTO to be ‘positive disequilibrium’.
ANSTO undertook disequilibrium analysis on 40 half metre full core samples, from 22 sonic holes at the Lake Way, Millipede and Dawson Hinkler deposits collected during Toro’s 2013 drilling season.
Of the 40 samples tested by ANSTO, 27 returned positive disequilibrium results.
Toro has interpreted ANSTO’S results to suggest the application of a disequilibrium factor of at least 1.2 may be appropriate to gamma results used to estimate existing Mineral Resources for the Wiluna uranium project, with the exception of the Lake Maitland deposit.
Toro acquired the Lake Maitland project in November 2013, and its Mineral Resource estimate already includes the application of a disequilibrium factor of 1.18 to gamma results.
This factor was determined from previous positive disequilibrium results.
During 2013 and the first half of 2014, Toro undertook a major drilling campaign at the Wiluna project, totalling 2,074 air core and sonic drill holes.
The purpose of the drilling was to provide further information on the continuity of uranium mineralisation and facilitate Ore Reserve calculations as part of the project definitive feasibility study when that study is commenced.
Early indications from the 2014 drilling program geochemical and gamma results support the positive difference shown by the ANSTO results.
Toro will now evaluate the magnitude and extent of the positive disequilibrium, and assess how to incorporate the findings into the Mineral Resource estimation process.
Email: info@toroenergy.com.au
Website: www.toroenergy.com.au