New Gold has launched an internally-funded strategy for the development of another block cave at its New Afton gold-copper mine in British Columbia, Canada, as it looks to extend production through to 2030.

While further details of the strategy are expected later in January, a 2016 feasibility study on the C-Zone implied another 25 Mt of gold and copper ore reserves, equivalent to five years of mine life, could be added through the development of the new block cave.

Early last year, the company decided to defer development of the C-Zone in 2018, electing to evaluate opportunities “that have the potential to further optimise the C-Zone project”. Some of the opportunities identified, which were not featured in the feasibility study, included different tailings options (such as dry stack or thickened/amended tailings), as well as mining approaches based on operating experience in the B-Zone (including reassessing the amount of required underground development in the cave as well as optimising draw bell and pillar designs).

New Afton is a block cave mining operation able to produce 4 Mt/y of copper-gold ore for processing in a flotation plant. The deposit has been partitioned into three zones. The two nearest the surface cave readily and provide the initial mine production, while the deeper block is expected to require assistance in cave development.

An undercut and extraction level has been developed at each block, with ore hauled to ore passes and dropped to a tramming level for transport to the crusher. Ore from the deeper block is hauled by 50-t truck to the crusher level, from where it is conveyed to the mill via a 4.5-km long conveyor system.

Since the start of the current underground block cave operation in July 2012, exploration at New Afton has focused on extending the mineral resource below the current B-Zone block cave reserve. This work has resulted in the development of the C-Zone mineral resource, which was stated as 18.3 Mt at 0.8 g/t Au, 2.2 g/t Ag and 0.95% Cu as of December 31, 2017.

While investors will await further news of the internally-funded strategy for the C-Zone, the existing mine exceeded guidance in 2018. It produced 18,778 oz of gold in the December quarter for 77,329 oz in 2018, above expectations. Copper output also toppled expectations, with 20.8 MIb (9,435 t) and 85.1 MIb for the quarter and year, respectively.

And expectations are for these positive results to continue into 2019.

New Gold said in the December quarter results release that it had started an “ore segregation” strategy during the quarter, which has been further enhanced with the recent commissioning of an ore scanner. This is expected to increase overall mill grade, New Gold said.

Also, during the quarter, the initial phase of a two-phase mill upgrade to address supergene ore recovery was completed on time and on budget. This included the installation of pressure jigs and a magnetic separator with commissioning currently underway.

The second phase of the planned upgrade will be launched during the current quarter, with commissioning scheduled for the September quarter, the company said.