Guinea's diamond resources are related to Cretaceous age kimberlitic sills dykes and pipes which exploited major north trending structures in eastern Guinea. It is estimated that at least 800m of erosion has taken place in this area, meaning that most primary kimberlite pipes and dykes have been eroded away. Subsequent alluvials are located in most rivers draining north of this area. Guinea has estimated diamond reserves of approximately 20 Mct.
Diamonds are Guinea's second largest export, after bauxite.
With the ban of unlicensed ventures, foreign mining companies have begun to invest in the diamond sector. K23 has been drilled and has an elongate structure measuring 150m by 50m and has not been drill tested past 166m depth. Outside of the Aredor mine, Hymex Diamond corporation operates the only other commercial diamond operation, the alluvial operations at Kerouane, which have recovered 43,665 stones weighing 24,022 carats. Most of Guinea's diamond production is produced by artisanal workers from alluvial workings. Debsam are apparantly carrying out a regional sampling program, including the drill testing of several kimberlite pipes and dykes.