The diamond, measuring 49 millimetres by 42 mm by 26 mm, was recovered from direct milling of ore sourced from the EM/PK(S) unit of the mine’s South Lobe area.
The 470-carat recovery forms a notable contribution to a series of top-quality gem and clivage quality diamond recoveries during a recent production run, including an additional five diamonds greater than 100 carats and 13 diamonds between 50 and 100 carats in weight.
Lucara shares were unchanged at 75 cents. The stock is trading in a 52-week range of $1 and 45 cents.
The company has said continued and consistent recovery of large diamonds, such as the 378-carat and 341-carat stones, comes at a critical time and provides continued strength and additional foundation to the underground expansion at Karowe that will see mining continue for at least another 13 years after the open pit ceases operations in 2026, the company said.
The current mine plan is based on probable reserves form surface to a depth of 324 metres below surface of 19.84 million tonnes containing 2.6 million carats. Total mineral reserves (including stockpiles) stand at 25.40 million tonnes containing 2.96 million carats.
The May production run, dominated by EM/PK(S) ore, produced diamonds greater than 10.8 carats in weight, accounting for 12.7% of total production, exceeding resource expectations. The company said strong resource performance and recovery of large diamonds reinforces the significance of the EM/PK(S) as an important economic driver of the proposed underground mine at Karowe.
The 470-carat diamond was recovered in the coarse XRT circuit and represents the third +300 carat diamond recovered to date in 2021. Year to date, Karowe has produced 10 diamonds greater than 100 carats including six diamonds greater than 200 carats. That includes the 341-carat and 378-carat top white diamonds recovered in January, 2021.
“The benefits of a South Lobe-dominated mine plan continue to be realized in 2021 and underpins our confidence in the ever-improving Karowe resource as we mine deeper in the open pit to 2026 and move into underground mining out to at least 2040,” said Lucara CEO Eira Thomas.
“Both main rock types from the South Lobe continue to deliver large, high-value diamonds, including six diamonds greater than 200 carats in the first five months of the year alone,” she said.
On January 4, 2021, the company said its mining license has been renewed and is effective for 25 years, securing the company’s mining rights to 2046.