Nevsun Resources has announced that, together with its Eritrean partner ENAMCO, Nevsun has approved an extension to the Bisha zinc-copper mine in Eritrea, self-funded by existing cash flows from Bisha. The open-pit extension adds 3.3 Mt of high-grade ore to the mill and extends operations through the full year 2022, resulting in additional payable production of 470 million pounds of zinc and 52 millions pounds of copper over this time frame. In addition to incremental production and revenue, the extension provides time for Bisha to advance assessment of the Asheli and Harena underground deposits and to consider further open-pit extensions.
The plan will see Heavy Mining Equipment spending of $20.9 million up to 2022 to “primarily to purchase larger mining equipment that is expected to yield a unit mining cost 23% lower than the existing fleet. The other costs include new maintenance facilities for the larger trucks as well as other initiatives and projects to deliver the mine life extension.”
Kukielski continued, “This open pit extension is supported by the now fully implemented metallurgical improvements at Bisha, combined with continued strength in zinc and copper prices. We will have an additional open-pit extension to consider late next year and are actively evaluating underground mining at Asheli and Harena. We continue to work with our partner, ENAMCO, to maximize resource conversion to reserves.”
In August 2017, Nevsun decided to reduce the mine life at Bisha due to the operational risk of the original large open-pit cut-back. Since that time, Bisha has increased mining rates and significantly improved metallurgical performance, while metal prices have remained strong, leading the Company to re-visit the larger cut-back option. The open-pit extension accesses a portion of the previously envisaged cut back with an additional 3.3 million tonnes of ore over the existing reserve and assumed recoveries of 70% for copper to copper concentrate and 80% for zinc to zinc concentrate.
Several million tonnes of additional high-grade resource in the original pit design could also potentially be brought back into the mine life. The Company expects to assess investment in an additional cut-back to access this resource in late 2019. Approval will depend on performance in delivering the cost targets and increased mining rates for the extension announced today.