Most of the effort so far is a battle of paperwork trying to hand off responsibility and covering your own behind.
Another regulation with good intentions, vaguely worded and broadly applied results in massive red tape for companies that have no control over the use/source of these materials.
Unless you employ significant penalties for anyone using conflict minerals, they will continue to be moved about and sold.
If you have inspectors who show up and take samples at random, you can begin to identify and police the people who "don't" care.
Just a thought.