By Chrispin Inambao ORANJEMUND As the land-based carat profile declines and diamond deposits in the Sperrgebiet could severely be depleted by 2020, the country’s prominent diamond miner Namdeb has of late shifted its focus towards untapped kimberlites in north-eastern Namibia. Kimberlites are a formation of diamond-bearing rock. This name was derived from a South African town Kimberley that was last century considered to be the world centre for diamond mining and is believed to be the site of the first diamonds found in rock. In a telephonic interview on Saturday, Namdeb’s Mineral Resources Manager Bob Burrell told New Era that at a recent tender board meeting, approval was granted for the alluvial diamond giant to commence mineral exploration activities in Western Caprivi and in Eastern Kavango where kimberlites were detected through aeromagnetic surveys. He said this year alone the global alluvial diamond giant has set aside an amount of N$16 million for ground geophysics and other exploratory work in north-east Kavango and western Caprivi and so far it has had meetings with the chiefs in the targeted areas. The meeting with the chiefs was mainly to “notify” them about Namdeb’s activities. Burrell says Namdeb has engaged joint partners Minnex, a South African company and Motapa, a Canadian company, to assist in diamond exploration in Caprivi and Kavango that could take many years before the actual mining takes place depending on deposits. When asked what the initial findings on these deposits looked like he said “it was far too early” and that even if the deposits are economically sustainable it could take “many, many years” before the actual mining could start. There is also a possibility the kimberlites have uneconomic or low diamond content per tonne of material excavated or mined. But he said the data from the ground geophysics survey from this “part of Namibia that is possibly prospective for kimberlites”, would be taken to Namdeb for interpretation. Motapa was also involved in similar prospective work in Zambia and Botswana and in some of the prospected areas the carat yield was found to be little and uneconomic. Namdeb has been involved in diamond exploration in the two northeastern regions over the past five years. Not all kimberlites are diamond bearing or economically viable, and when kimberlites are found it is necessary to evaluate the diamond content (carats per tonne), the size of the deposit and also the size and the quality of the diamonds. The last two characteristics are important to know because in the diamond mining industry, the product is valued in terms of individual pieces. In a kimberlite, there is a relationship between the quality of diamonds and the abundance of fragments from the mantle host rocks where diamonds form. To determine diamond content, tonnes of rock are collected from the top of the pipe and processed. If diamonds are found, drilling and petrological examinations will give the extent of the deposit and information about the diamond content. Between 5 000 and 10 000 carats of diamonds are needed to fully evaluate a deposit. A diamond concentration that would allow an economic development of a mine would be around 0.5 carats per tonne while a very good one would be in the range of 2 to 4 carats per tonne. The distribution of diamond size and quality also needs to be determined to be able to select a development strategy like surface excavation or underground mining. Last year Namdeb’s diamond production exceeded 2 million carats for the first time ever but this trend is set to decrease substantially from 2014 until 2020, when this strategic resource could be depleted, while a large number of its workers would also be retrenched. Over the past 100 years Namdeb and its predecessors have extracted over 80 million carats of gem-quality diamonds from operations in the Sperrgebiet area.