THE DIAMOND PAGE — DiamondWorks starts mining in Angola

DiamondWorks (DMW-V) has begun mining alluvial diamonds at its Luo project in Angola, following the commissioning of a 120-tonne-per-hour floating dredge.

The dredge, airlifted in from South Africa, began limited mining of diamond-bearing gravel from the Chicapa River Valley in mid-March. The dredge is operating where the river flows over a section of the Camatchia kimberlite pipe.

“The start of production at Luo marks an important milestone for DiamondWorks,” says Chairman Eric Friedland. “We remain on schedule to begin full-scale commercial production in May.”

The 27.9-ha Camatchia pipe contains proven and probable reserves estimated at 26 million tonnes grading 0.11 carat per tonne to a depth of 96 metres, or 3 million carats and an additional 10 million carats in inferred reserves below that.

Camatchia is one of the world’s largest diamond pipes, and one of five known pipes on the Luo concession.

The diamonds being recovered will be evaluated to identify key target areas for future mining along some 20 km of the Chicapa River, which flows through the property in Angola’s Lunda Norte province.

Gravel recovered by the dredge is being processed using an interim system of pans and grease tables. All tailings are being stockpiled for reprocessing through the new dense media separation (DMS) plant, which will soon be airlifted from South Africa.

The DMS plant will be integrated with the existing pretreatment plant and can concentrate diamonds from about 100 tonnes of alluvial material each hour.

The diamonds will be recovered using high-security Sortex machines.

In addition to alluvial mining, DiamondWorks plans to carry out bulk-sampling on the Camatchia pipe, on the west bank of the Chicapa River, and on the 20.7-ha Camagico pipe, about 8 km to the south.

Meanwhile, in Sierra Leone, the company will begin bulk sampling from the two Koidu pipes as part of the project’s final feasibility study.

The accumulated silt is being removed from the existing mining pits over the pipes, and the pits are being surveyed in preparation for drilling and blasting.

Some 10,000 tonnes of kimberlite will be mined and processed from each of the pipes. The total bulk sample is expected to yield 10,000 carats of diamonds for independent valuation.

Proven and probable reserves at Koidu are estimated at 7.6 million tonnes grading 0.352 carat per tonne, for a total of 2.7 million carats.