Mining Magazine > Panorama > Lundin evaluates Neves Corvo handling options

Panorama

Lundin Mining Corp has completed a future underground materials handling study for its Neves-Corvo mining complex in southern Portugal. This conceptual level study identified and evaluated the underground materials handling and access options necessary to pursue the exploitation of the deeper Lombador copper/zinc resources, as well as the Semblana copper deposit which are adjacent to the mine.

The study indicated two preferred options:
•    A new rock-hoisting and man-riding shaft approximately 1,200m deep, located to the north-east of the existing mine surface facilities, situated between the Semblana and Lombador mineralisation, and
•    A new decline from the existing plant area equipped with a conveyor system and man and material access facilities. This consists of a proposed two-leg decline driven by a high speed TBM and would be aligned to pass close to and underneath the Semblana deposit and then on to deeper parts of the Lombador resource, reaching a similar ultimate depth as the shaft option.

The shaft option is expected to comprise conventional shaft systems with combination skip/cages providing a designed rock hoisting capacity of 5Mt/y, coupled with rapid man-riding facilities to the lowest levels of the mine. The shaft would provide direct ventilation benefits and would allow ore and waste from production areas to be gravity-fed to a new deep haulage level. The shaft is expected to provide less positional and sequencing flexibility, as well as a longer development schedule, as compared to the decline option.

Should the shaft option be selected, it could be in production approximately 5 years from project start. It is expected to have a higher capital cost and lower operating cost than the decline option.

The decline option is expected to comprise a 6m diameter, inclined tunnel equipped with a conveyor system for rock hoisting, with the same design capacity as the shaft option. At a current design gradient of 1:5, the length of the decline from surface to the Semblana area is approximately 5,200m.

Access to the deeper parts of the Lombador mineralisation would require a decline extension of a further 2,200m. Man access would be provided by a rope haulage system or conventional vehicles depending on the final selected gradient of the decline.

The decline option is expected to allow earlier first production than the shaft option, with potential to be operational in approximately four years from project start. This option would also allow phased expenditure and sequential development of the Semblana and Lombador mineralisation. The decline option could also have the added benefit of providing greater flexibility in accessing several other areas of potential mineralisation located near the Semblana deposit.

The next level of study is advancing with a high priority, taking into account ongoing new exploration results, and to further develop designs and comparisons between the two options. Capital and operating cost estimates for the shaft and decline options are still at a conceptual stage, and Lundin expects to refine comparisons between the options with anticipated completion by the June quarter 2012.

Paul Conibear, CEO of Lundin Mining said, “The successive stages of refinement of the materials handling study are essential for the future development of new resources at Neves-Corvo. We intend to move forward aggressively with investment plans at the mine. Ongoing exploration efforts on Semblana, Lombador, and the drilling success we have recently achieved on new targets will continue to shape and support our investment in future underground materials handling infrastructure at Neves-Corvo.”