(ShareCast News) - AIM-listed explorer Botswana Diamonds has started a drill programme at its mine in the Kalahari Desert and is "cautiously optimistic" of finding kimberlites. The company has started a first phase four dole drill programme on the PL135 licence in the Gope region of the Kalahari Desert for kimberlites, which is part of joint venture with Alrosa, a Russian diamond producer.Chairman John Teeling said: "The Gope drill campaign is breaking new ground in one of the most remote deserts on Earth. There are no people, even water must be transported long distances and the sand is deep. Temperatures can differ by 50 Celsius between day and night."No mining companies have ventured here before to undertake drilling programmes. And yet the preliminary geochemical and geophysical indicators are strongly positive. We are at the cutting edge of diamond exploration and are cautiously optimistic of finding kimberlites."It was selected in separate studies by the company's and Alrosa's geologists for significant potential and it has not been previously drilled.Intensive soil sampling and electromagnetic studies found anomalies in the geology with the core to be analysed by Alrosa mineralogists with results expected in twelve weeks , with further evaluation and analysis, if needed, in St. Petersburg.On Tuesday, the company said it had started drilling on the kimberlite pipe AK22 on its PL260 licence in the Orpa area, again a joint venture with Alrosa.Shares in Botswana Diamonds were up 12.28% to 1.60p at 1035 BST.