Site works began in May last year and the project was completed by project manager Bateman Materials Handling in April this year.
The new plant will boost production at the mine by more than 30% to 60 000 ct/y of highly sought-after gem-quality diamonds.
"The plant upgrade has created 15 new positions and 52 employees have undergone additional skills training, which has placed them in high earning occupations," says THG operations MD Peter Danchin. Efficiencies obtained by the new plant have reduced total unit operating costs by 37%, which has reduced the ore grade required for profitability.
This has extended the overall life-of-mine to 14 years – another positive development for local employment.
The payback period at present diamond prices and interest rates is expected to be two-and-a-half years.
"With the commissioning of the new plant we have introduced a three eight-hour-shift system operating five days a week year round – a departure from the previous two shift eleven-month programme – a development fully endorsed by organised labour," says Danchin.
The new plant, capable of treating 1 300 t/h of diamond-bearing gravel feed, has replaced three smaller plants that will be mothballed and used in future exploration activities.
Baken's treatment plant, which has increased throughput by 67%, has two trommel screens capable of processing 650 t/h each.
The dense media separation (DMS) plant stockpiles more than 3 600 t.
Two units processing –25 mm to +2 mm material at a rate of 150 t/h each are contained in the DMS system.
Based as a percentage of total plant throughput, the final recovery plant has a guaranteed throughput of six tons an hour.
The percentage of run-of-mine that goes through the hand sorter is 0,0023%.
The plant uses 5 MVA of power and consumes 350 m3 of water an hour.
Standing on its own, 50 km upstream from the coastal town of Alexander Bay on the left bank of the Orange river, 158 tractor trailer deliveries were made to site to erect the processing plant.
It was constructed with 938 t of fabricated steel and platework; more than five kilometres of conveyer belt was installed; 3 123 m3 of concrete was poured; and 88 km of electrical and instrument cabling has been installed.
THG achieves some of the highest run-of-mine diamond prices in the world and the Baken operation has averaged over $800/ct over the past year.
The highest value per carat diamond in the company's history – a 24,04 ct light pink, selling for $25 042/ct – was recovered in Baken.
The gem group markets its diamonds independently through a tender system under the auspices of the South African Diamond Board.
All diamonds offered for sale carry a Certificate of Origin, indicating their 'conflict-free' status.
A silent benefactor of the plant upgrade will be the Namaqualand Diamond Fund Trust (NDFT) – a statutory body representing the inhabitants of seven regions in Namaqualand.
The NDFT receives a 4,5% royalty from all diamond sales originating from THG's Namaqualand mines.
These funds are used for community infrastructural needs, educational programmes and skills training.
Since mining began in 1981, THG has paid more than R114-million in royalties to the NDFT – with R14-million contributed in financial 2001.
The central plant upgrade could boost this annual figure by 30%. In addition to its onshore operations, the company has entered into a joint venture with Namibian sea concession-holder Diamond Fields International.
This will involve deep-water mining off the L