Mwadui diamond revenue up 15pc

MWADUI’S Williamson Diamond revenue has increased 15 per cent due to the higher proportion of run of mine (ROM) versus alluvial diamonds for the year.

The mine, contributed 15 per cent of total Petra Diamond revenue for the year that went up to 62.1 million US dollars in 2015 compared to 53.9 million US dollars in 2015. Petra, the mother company of Williamson Diamond, said in a financial statement yesterday that production carats increased by 7.0 per cent to 202,265 carats.

The miner financial year starts in July and ends in June. The ROM throughput is planned at 3.8 metric tonnes in this financial year, lower than previous guidance of 4.5mt due to downtime associated with the aforementioned plant modifications.

“This is a particularly relevant strategy at this lower grade operation and the modifications are planned to enable the mine to reach throughput of 5 Mtpa by 2018,” the report said. The modification sought to raise a grade of circa 7.0 carats per hundred tonnes (cpht) from previously guided circa 6.0cpht.

Petra’s current mine plan for Williamson has a lifespan extending to 2033, but given that the Mwadui Kimberlite hosts a major resource of 33.1 million carats per hundred tonnes (mcts), there is potential to extend the life of mine considerably.

A decision was taken by management last year to carry out plant modifications at Williamson in order to improve throughput and diamond liberation. Such an increase in ROM grade, partially offset by a finer diamond size population, is expected to yield between seven and 10 per cent increase in revenue per tonne.

The plant enhancements will include the introduction of an additional crusher circuit and two autogenous mills, with construction commencing in 2016. The commissioning of the crusher planned for this year and installation and commissioning of the two autogenous mills planned for first half of next year.