Firms that dig tin in eastern Democratic Republic of Congo, merchants and ends users have launched a monitoring scheme to show armed groups are not profiting from mines, an industry body said on Friday...Mining is one of the principal sources of income and jobs in eastern Congo, but bad publicity surrounding so-called "conflict minerals" prompted Belgian metals merchant Traxys and tin smelter Thaisarco to stop buying material from the area last year...The scheme "will begin to track minerals and provide verifiable provenance information from individual mine sites in eastern DRC; something that has not been possible up to now," tin industry federation ITRI said in a statement. [Also refers to Apple, IBM, Sony]