Lundin More Than Doubling Zinc Production at Neves-Corvo
Pre-production capital costs for the expansion project are estimated at €257 million, including a 15% contingency. Payback is estimated at less than four years from the start of production. Neves-Corvo is an underground mining operation that currently mines five orebodies. Ore occurs in zinc-rich and copper-rich zones and, based on mineral content, is processed through a zinc concentrator or a copper concentrator. The copper concentrator has throughput capacity of 2.6 million mt/y, which will remain unchanged as zinc plant capacity is being expanded.
Feed for the expanded zinc concentrator will be derived from ongoing production from current mining areas and the development of a deeper, higherzinc- grade mining area known as Lombador Phase 2, which will be accessed via ramps from current operations. Additions to the mining fleet will include two drill jumbos, two rockbolting rigs, five LHDs and explosives loading platforms.
A new underground crusher will be installed, and an inclined, approximately 3.2-kilometer-long, three-leg conveyor system will be installed to move mined ore up to the base of the existing production shaft. The shaft will be expanded from its current hoisting capacity of 4.9 million mt/y to 5.4 million mt/y to handle the expanded mining production.
Modifications to surface zinc-ore processing operations will include new grinding and flotation buildings, a new control room and electrical rooms, and a new emergency stockpile feed system. Processing equipment will include a new 8.5-megawatt (MW) SAG mill for primary grinding. Secondary grinding will be carried out in existing mills ahead of newly installed and increased lead and then zinc flotation capacity. Upgrades are also proposed to lead thickening and filtration, water supply, and reagent circuits. Extensions to the mine’s ventilation, pumping, electrical reticulation and other infrastructure are planned.
The primary electrical feed to the Neves-Corvo site and the existing substation are capable of handling the increased power demands. The additional volumes of tailings to be produced will necessitate an expansion to the tailings thickening plant, while the tailings themselves will continue to be deposited in an expanded tailings management facility. Subject to receipt of anticipated environmental approval in the third quarter of 2017, Lundin expects to begin construction on the expanded zinc plant in the first quarter of 2018, with commissioning and ramp-up to be completed by the end of 2019.