Name and Location
Finsch mine expansion project, Northern Cape, South Africa.

Client
Petra Diamonds.

Project Description
The expansion of the Finsch mine will take production from about 1.4-million carats a year to 1.8-million carats a year by the 2016 financial year and to two-million tons a year by the 2019 financial year.

Current production is entirely from Block 4, which is a mature block that has mostly been mined out, resulting in ore being heavily diluted with waste rock.

To provide earlier access to undiluted ore before the main Block 5 Cave is established, Petra will use the sublevel cave (SLC) mining method over four levels from the 710 m level (mL) to the 780 mL, at a rate of 3.2-million tonnes a year. Once the transition is made from mining the SLC to the main Block 5 Cave, which is currently planned at the 900 mL, tonnages will increase to 3.5-million tonnes a year from the 2021 financial year.

Value
Not stated.

Duration
Not stated.

Latest Developments
In August this year, Petra announced enhancements to the expansion plan at Finsch, which will focus on revisions to the ore-handling system, including the implementation of a conveyor system that can transfer 710 mL to 780 mL SLC material to the existing loading and hoisting infrastructure on 650 mL; a further enlarged footprint of the Block 5 SLC; and the doubling up of crusher capacity to complement the enhanced ore-handling and engineering infrastructure, planned at the SLC and the Block 5 Cave, which was originally planned for the Block 5 Cave elevation only.

These measures will improve production flexibility and enable more efficient managing of grades and the earlier decommissioning of the Block 4 automated ore-handling infrastructure, resulting in long-term savings in operating costs and the added benefit of production efficiencies.

Run-of-mine (RoM) throughput is guided at 2.83-million tonnes for the 2014 financial year at a grade of about 32 ct per hundred tonnes (cpht) to 33 cpht. As the mine’s production profile gradually changes from diluted to undiluted ore, the RoM grade is expected to increase to an estimated 36 cpht by the 2015 financial year, to about 43 cpht by the 2016 financial year and to about 56 cpht by the 2017 financial year – up from previous guidance of 47 cpht and assisted by the plant changes mentioned, when full production is sourced from undiluted ore.

Meanwhile, the development of the declines and access tunnels, which are key deliverables at this stage of the project, is progressing in line with expectations and the development and drilling contractor services have been established. The successful progression of the programme is evident by the significant increase in development metres achieved for the year – 2 311 m in the 2013 financial year, compared with 169 m in the 2012 financial year.

Raiseboring activities also started in the fourth quarter of the 2013 financial year and yielded 165 m.

Treatment of the ‘pre-79 tailings’ is planned at 2.65 Mt for the 2014 financial year and expected to be mined for a further two to three years, at a grade of about 21 cpht to 22 cpht (an increase from the prior guidance as a result of the plant changes). Once the pre-79 tailings have been depleted, treatment of the post-79 tailings will continue until the 2020 financial year, at a lower estimated grade of about 10 cpht.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Petra Diamonds, tel +27 11 702 6900, fax +27 11 706 3071 or email info@petradiamonds.com.