Ann: West Arunta Project - Luni Metallurgical Results, page-152

In WA1 2.2.24 they announced the program commencement : "Following receipt of diamond core samples in Dec, the Company has now commenced targeted metallurgical testwork programs at select laboratories both locally and internationally.", adding the 5 month timeline in WA1 21.2.24, which together implied end of Jun completion.
In today's announcement they said; "The primary objective of the flotation testwork was to demonstrate that the niobium mineralisation (both pyrochlore and columbite) is amenable to concentration via flotation. This objective was achieved sooner than expected,...", hence you might expect an earlier completion and the timing of today's announcement may simply reflect ASX continuous disclosure.