Premier African Minerals Limited (LON:PREM) has made further progress at the RHA mine in Zimbabwe - reporting a 300% increase in the open pit resources there.
The firm said this supported its planned production levels of up to 10,000 metric ton units of tungsten per month when installation and commissioning of the upgrades underway at the mine are complete.
Open pit resources and inventory now stand at 20.8 million tonnes at an increased grade of 2.34kg per tonne.
The group's first underground resource in developed areas was put at 1.3 million tonnes at 4.25kg per tonne, and a 40 year mine life is indicated.
The total therefore of underground and open pit is 22.149 million tonnes.
Premier chief executive George Roach told investors: "This maiden resource in the underground and update on the open pit, strongly supports the installation of X-Ray (XRT) based run-of-mine sorting technology and indicates a sustained profitable operation once the shaft upgrades are completed and the sorter is installed.
"At the same time, the production at this level is likely to see Zimbabwe placed into the top five wolframite producing countries and RHA as one of the larger producers outside of China."
Premier owns 49% of RHA and is the operator.
Shares added almost 8% on the day to stand at 0.324p.