The Cattle Creek 2019 drilling programme sampling density is significantly greater than prior work and allows us to delineate new higher-grade rare earth (REE) areas below the alluvial sediments. In previous drill programmes, scandium was identified but not considered significant, so subsequently it was not routinely assayed. Grade modelling work in mid-2020 by SRK Perth, has identified potentially economic volumes/regions of scandium and REE grades in puggy clay and saprolite rock types. Further infill drill intercepts from the 2019 drilling programme, passing through these zones await assay. Drill sample assay work was deferred, focusing funding on metallurgical work. In July 2021, Enova committed to the submission of 70 composites for assaying. This constitutes the partial completion of assaying for an additional seven holes (132 lineal metres).
Previous project studies focused solely on the recovery of monazite/xenotime minerals from alluvial sediments by gravity separation. Further laboratory-scale gravity test work was completed from late 2019 to early 2020 by Mineral Technologies and IHC Robbins Brisbane to confirm prior results with the new drilling samples. Further work was completed by Brisbane Metallurgical Laboratories by mid-2020. Additional tests were also undertaken: included particle size analysis, classifier and cyclone upgrading tests for different rock types.
Following on from these tests, work focused on leach extraction of REE (and Sc) from in situ weathered saprock (variants), puggy clays and weathered bedrock, all of which have appreciably higher REE (and scandium) grades than the overlaying alluvial sediments. Initially, our laboratory 'sighter' leach tests ( 6 tests) were a process of discovery. Since mid-2020 we have completed multiple leach tests (13 tests) and gained extensive experience. Tests demonstrate exceptional leach efficiency under certain conditions. Current leach tests are focused on reducing acid consumption and finding optimum leach conditions. Our most recent tests focus on roasted (and unroasted) sample preparation followed by heated leaching at different acid concentrations at various dosage rates. Test work can then focus on metal adsorption and tailings neutralisation.
Results from our metallurgical test work currently in progress will dictate our process options going forward, so it is of utmost priority. It has knock-on effects on all other aspects of the project. Enova is confident project development will quickly accelerate with this work completed. Our efforts are slowed by limited funding, our testing is sequential and each test takes three weeks to obtain assay results. With increased funding, several tests could be completed in parallel.
Refinery product test-work is also required to provide greater confidence in the refining process, product yields and specification. Large scale laboratory test-work, involving bulk material processing, is required to obtain sufficient concentrate for refinery test work. This work also serves to provide metallurgical and engineering “proof of concept” for several of the concentration processes; normally these tests are completed during the pre-feasibility stage. With the JORC resource report update, Enova can seek further funding to commence work necessary to complete the Scoping Study.
By completing the described work programmes, Enova can update the Stage 2 Scoping Study, the basis to raise funds at significantly higher market value. The total budgeted cost of the process/refinery test work programmes and the Stage 2 Scoping Study update are estimated to be $750,000 to $1M.
Sizing and Tabling Test Work (Brisbane) - Completed May 2020
Updated July 2021