Canada-based Nevsun Resources has completed the new zinc flotation plant at its 60%-owned Bisha mine in Eritrea.
Adding to the existing copper flotation and Bisha, the new plant will continue to produce copper, as well as zinc for the remaining current nine-year primary reserve life.
Nevsun Resources CEO Cliff Davis said: "We are again very pleased with how the zinc plant expansion has progressed, on time and under budget.
"We look forward to reaching commercial production before the end of Q3. In the meantime, we will continue to accelerate the monetisation of the DSO high-grade gold equivalent stock piles so as to augment cashflow during 2016."
The Bisha zinc expansion project is expected to average more than 100,000t of zinc and 20,000t of copper per year for the next nine years from the middle of this year.
As part of the project, the copper regrind mills were replaced with a new IsaMill, which is the same as the zinc plant's mill.
The company also completed wet commissioning tests, utilising air, water and slurry.
Bisha has started hot commissioning to generate combinations of copper, zinc and bulk concentrates until transition to commercial production later.
Using this process, Nevsun will be able to optimise the efficiency of the plant and increase recoveries of copper and zinc in their respective concentrates.
The company currently estimates the project cost to be less than $80m.