East Africa FT correspondent Katrina Manson visits mineral traders in Rwanda and Democratic Republic of Congo to investigate efforts to clean up smuggling rackets that have repeatedly funded conflict in eastern Congo. She finds new legislation crafted thousands of kilometres away in Washington has backfired – Congo’s official exports have ground almost to a halt; conflict and smuggling continue and holes in a new tagging system has delivered a gift to the very people it was intended to stop.  (Video, 4m 19sec):