De Beers Consolidated Mines is only four years away from recovering the first carats from its US$2 billion Limpopo-based Venetia underground mine, writes Laura Cornish.The mine may be the only asset in the company’s South African portfolio in the nearby future (Voorspoed is up for sale) – it is and will remain a world-class, tier one partially automated operation and the third largest in the entire De Beers Group, with potential to expand.
While the majority of underground production will be delivered from the K01 pipe (below the K01 pit), scheduled to start in 2023 and reach nameplate capacity approximately 24 months later, the smaller K02 underground mine will serve as a production buffer from 2021.
“The K02 open pit resource has been depleted to a depth of 350 m and will serve as the exit point for material to be delivered from the underground mine to surface from 2021.
Decline development for this mine is well underway and advancing according to plan,” says Phillip Barton, CEO of De Beers Consolidated Mines.
The larger scale K01 open pit’s mine life will finish in 2023, facilitating the production start-up from the underground resource immediately thereafter.
“Mining cannot start earlier as concurrent open pit and underground operations are not possible on the same pipe so we need to ensure a smooth transition from open pit mining to underground mining with no overlap.”
This article first appeared in the November edition of Mining Review Africa, to read the full article click here.
To ensure this, all necessary supporting underground infrastructure (including ore passes, rim tunnels, etc.) will be complete and ready for production start-up as soon as the last open pit truck leaves the mine.
Barton notes that Venetia is expected to realize a slight drop in production as the mine transitions, but adds that the company has incorporated a ‘stockpile strategy’ into the production profile to keep the tonnages constant, albeit at lower grades.
“The early onset of K02 will also help to mitigate against this drop.”
The plant will operate at a 6 Mtpa ROM capacity (as is scheduled for now) and it will deliver 4.5 million carats per annum over its lifespan which is currently forecast for closure in 2046.
This however could change.
“While our production constraint lies with the plant which can only handle 6 Mtpa, our underground infrastructure has been designed for 8 Mtpa.
"We do however believe there is potential to de-bottleneck our 25 year old process plant through the incorporation of new technologies which remains an on-going process of investigation and practice,” Barton reveals.
“De Beers has a long history of diamond recovery and we have become experts in X-ray technology more specifically. Ultimately, we believe this is an area that could have significant de-bottlenecking results for us in time.”
And while such a project would reduce Venetia’s lifespan, DBCM is already evaluating the possibility of extending this to 2050 or even 2060.
These are blue sky plans at this stage but even so, it is important to take cognizance of the mine’s future potential beyond current plants.
Converting inferred resources at depth (below 980 m at K1 and 600 m at K2) will form part of this exercise. Maintaining production and bringing the new underground mines on-stream as planned is however the top priority at present.
Feature image credit: Wikimedia