Aim-listed Bushveld Minerals’ updated mineral resource and ore reserve for the Vametco vanadium mine near Brits on the western limb of the Bushveld Complex has indicated a significant increase in ore reserves and grade from the 2017 estimate, Bushveld CEO Fortune Mojapelo indicated in a statement on Wednesday.
The updated mineral resource and ore reserve incorporates data from the 2018 drilling campaign, which comprised 13 drill holes over 1 506 m, and has been compiled in accordance with Joint Ore Reserves Committee reporting standards.
“The conversion of additional indicated mineral resources to probable ore reserves, plus the larger pit shell, means we have added significant increased production life at Vametco. In fact, even at the future expanded rates of production we have previously laid out, this mine will operate for decades into the future.”
Ore reserves have more than doubled to 279 100 t of vanadium pentoxide (V2O5) in magnetite, compared with the previously reported reserves of 137 152 t V2O5 in magnetite, notwithstanding the 5 700 t of vanadium produced between October 2017 and March 2019.
The grade, meanwhile, increased to 2.02% V2O5, from 1.96% V2O5 previously.
Indicated resources have increased by 187% to 965 900 t V2O5 in magnetite, compared with 336 604 t V2O5 previously.
The recently drilled holes added further confidence to the mineral resource, resulting in a higher ratio of indicated mineral resource to the inferred mineral resources, constituting 75% of the total mineral resource.
The aggregate inferred and indicated mineral resource is distributed across three seams – the lower, intermediate and upper seams – and is reported as 186.7-million tonnes at an average grade of 1.98% V2O5 in magnetite, with an average magnetite content of 35% in whole rock for 719 300 t of contained vanadium.
Within this, the ore reserve in the probable category is reported as 48.4-million tonnes across the three seams, at an average grade of 2.02% V2O5 in magnetite, with an average magnetite content of 28.5% in whole rock for 156 300 t of vanadium.
The 31% increase in the 2019 mineral resource over the 2017 estimate is primarily attributed to reporting the mineral resource to a maximum depth of 150 m below surface, versus 120 m in 2017.
A relatively higher grade in the 2019 estimate resulted from better definition of the mineralised units owing to the recent drilling, which allowed the re-scrutinising of historical data.
This, together with reporting the mineral resource at a cutoff grade of 20% magnetite (previously no cutoff grade was applied), resulted in a higher-grade mineral resource than in 2017, particularly for the upper seam that is now defined as a layer of massive magnetite.
The magnetite content grade increase in the ore reserves from 26.8% to 28.5% is a direct result of the increase in magnetite content in the mineral resources.
The impact of this translates to additional potential ore production and vanadium through the processing plant.