Gemstone producer Richland Resources (LON:RLD) today announced a resource upgrade for its tanzanite mine in Tanzania.
The total inferred and indicated resource now stands at 105 million carats - an increase of 33 million carats, the firm said.
The new JORC compliant numbers mean the life of mine of the project has been extended by around 30 years - using the indicated resource alone, based on a ramped up production of 2.7 mln carats.
Chief executive Bernard Olivier said these were "significant, positive" developments for the firm as it looked to begin ramping up production over the next five years.
"In addition, following on from the recent JV announcement, the 33 million carat increase in the total size of the inferred and indicated resource consolidates Richland as one of the premier coloured gemstone mining operations in the world," he added.
The estimate comprises an indicated resource of 30.6 mln carats and an inferred resource of 74.4 mln carats.
It was based on a review of around 5,075 metres of drilling over 17 holes along with mine production between 2001 and the middle of last year.
Between the previous resource estimate in 2004 and 2011, the mine generated more than 11.5 million carats from around 266,000 tonnes at an average grade of 43 cpt (carats per tonne).
In December last year, the company revealed it had entered into a tanzanite joint venture agreement (JVA) with a group of Tanzanian individuals who own government mining licences for exploring and mining an area 2.5 km south of its existing mine.
If successful, it will mean feedstock from the new area, which consists of three tenements, will be fed through the firm's existing processing and sorting plant. The area is currently believed to contain an estimated 500 metres of strike.