SUNTECHOLOGY. lumumba, LUBUMBASHI, KATANGA, Congo (DRC),2000. We are supply of Coltan, gold, cassiterite, copper, cobalt and diamonds available in DRC congo we proving safe source. our coltan is 25% to 40% pure at competitive prices. can provide any quantities,contact us on : 243 81 478 6867 ... coltan, gold, copper, cobalt, cassiterite.