The Richmond – Julia Creek Mineral Resource is hosted in soft oxidised marine sediments as opposed to many hard rock resources around the world.
Exploration is a relatively low impact process due to this. With such a soft and shallow deposit aircore drilling is the preferred method and has been used previously in the area and by Richmond Vanadium. Aircore drilling uses hardened steel or tungsten blades to bore holes into the soft ground. An aircore drill rig is mounted on the back of a light truck or utility vehicle. Each hole drilled is around 20 metres deep and 15 centimetres wide and takes less than half an hour to complete. The drill rig consumes negligible water and makes little noise. Following drilling the holes are capped with specialised hole plugs and covered over with soil, with minimal disturbance to the surface.
A small regional drilling program was undertaken in 2018. In late 2019 RVT completed an infill drilling program on the Lilyvale deposit comprising 333 aircore holes for 7,817m. The aim of the drilling was to infill previous drilling to enable an Updated Mineral Resource estimate at an improved JORC Category from Inferred to Indicated. The drilling was highly successful in intercepting remarkably consistent oxide mineralisation along section. The grade has improved, relative to historic resource, by this infill drilling.
Extensive metallurgical testwork initially focussed on upgrading the run of mine ore prior to downstream processing of the concentrate. Results from the concentration tests using simple screening, gravity and flotation mineral dressing techniques produced excellent results with the concentrate comprising 21% of the original mass at an improved grade of 1.6% V2O5 and a 73% recovery (see ASX:HRZ announcements dated 8 May 2018 and 26 November 2018).
Downstream pilot plant testing utilising conventional techniques produced commercial grade vanadium pentoxide with acceptable recoveries. With the success of the pre-concentration and downstream testwork, work has now advanced to simulated production tests.