Notably, the company has achieved an 18.8% increase in reserves from 92.2 million tonnes to 109.5 million tonnes.
Metro managing director and chief executive officer Simon Finnis said: “We are pleased to report the increase in Reserve, effectively extending the mine life of Bauxite Hills, and the greater level of confidence in the total Resource.
“There has been strong reconciliation from the results of mining to date and the Resource and Reserve model. The results of this update demonstrate our increased confidence in the project.”
The total reserve estimate for Bauxite Hills is now 109.5 million tonnes (wet) and takes into account depletion to March 2019 and additional conversion of resources.
The overall increase in reserves (taking into account depletion by mining) is 17.3 million tonnes or 18.8% from that published in March 2017.
Importantly, this has the potential to extend mine life by about three years to 2037, at the expanded run rate of 6 million tonnes per annum.
The total measured resource is now 78.1 million tonnes (dry), representing a 42.8% increase of the measured category from that published in March 2017, reflecting greater levels of confidence in the resource.
There has also been a slight improvement in alumina and silica grades.