Coltan extraction causes problems that adjoin or overlap those caused by blood diamonds and uses similar methods such as smuggling across the porous Rwandan border, environmentalists and human rights workers began to speak of "conflict minerals" or "conflict resources" more generally. It is difficult to verify the sourcing of fungible materials like ores, so some processors, Cabot Corporation (USA) for example, have announced that they would avoid unsourced Central African coltan altogether.
