Lonrho Mining has recovered its highest-ever grade of diamonds, ranging up to 6.2 carats, after processing alluvial gravels from the BLK_06 bulk sample of the Lulo project in Angola.

The 19 million diamonds were recovered from less than 60m3 of alluvial gravels processed through the firm’s dense media separation (DMS) plant for an average grade of 31.86 carats per 100m3.

BLK_06 is part of a series of bulk samples designed to evaluate ancient alluvial gravels identified within the valley of the Cacuilo River.

BLK_06 targeted ancient gravels of the Calonda Formation, which are up to 2m thick and covered by 4m of overburden.