The Tanzanian Government has approved Acacia Mining's plan to start underground mining at its Gokona pit at the North Mara project.
Environmental impact assessment approval allows the company to begin commercial production during the second quarter this year, when Gokona open pit operation will be completed.
North Mara production is expected to be a combination of high-grade underground material from Gokona underground and open pit material from the Nyabirama pit for five years.
The underground project is expected to produce 450,000oz over its planned five years in operation, with possible lateral extensions and mineralisation remaining open under 300m vertical depth cut-off.
Acacia Mining CEO Brad Gordon said: This project is reflective of our new approach to operating our assets whereby we have re-engineered the mine to drive free cashflow and at the same time have significantly reduced the mine's footprint, which helps our relationships with the communities around the mine.
According to Acacia, Nyabirama pit and Gokona underground operations will enable the company to produce of more than 250,000oz of gold a year from North Mara mine.
North Mara started production in 2002 and has produced more than two million ounces to date. The life-of-mine is currently estimated to be nine years based on its reserves.
In November 2014, Acacia's board approved the underground operation at the Gokona pit.
The definitive feasibility study carried out by independent consultant Mining One has confirmed an attractive return for the company.
Formerly African Barrick Gold, Acacia Mining is one of the major gold producers in Africa with three mines in north-west Tanzania, and a portfolio of exploration projects in Tanzania, Kenya and Burkina Faso.
Image: Gokona underground operation is expected to produce 450,000oz over five years. Photo: courtesy of Acacia Mining plc.