(IDEX Online) - Lucara has announced another huge diamond - a 692.3-ct Type IIa high white gem - just two weeks after the recovery of a 1,080-ct stone.Both are from the Karowe mine, in Botswana, which the Canadian miner has operated since 2012. Lucara says the diamond measure 46.5mm x 40.7mm x 28.4 mm. It is the fourth +300-ct diamond recovered this year and the 20th +100-ct.Earlier this month the miner, famous for the Lesedi La Rona and Sewelo diamonds, recovered its fourth +1,000-ct stone.The 692-ct diamond was recovered from the direct milling of ore sourced from the EM/PK(S) unit of the South Lobe at Karowe.William Lamb, who has now taken over from Eira Thomas as CEO, said: "The successful track record of delivering some of the world's largest diamonds continues with the recent recovery of a 692.3 carat diamond."The recovery of large diamonds from the EM/PK(S) lithology of the South Lobe strongly supports our expectations for the underground project where the majority of material mined will constitute this phase of kimberlite during the first years of underground production."The underground expansion at Karowe should extend the mine's life until at least 2040, but costs are up 25 per cent on the original forecast (from $547m to $683m) because of technical challenges, and production won't now start until the first half of 2028, rather than the second half of 2026.Pic courtesy Lucara