"From a remote corner of northeastern Myanmar, an insurgent army sells tin ore to suppliers of some of the world's largest consumer companies"

Reuters:

More than 500 companies, including leading brands such as smartphone maker Apple, coffee giant Starbucks and luxury jeweler Tiffany

...

The mine is controlled by the United Wa State Army (UWSA), which the United States placed under sanctions for alleged narcotics trafficking in 2003. The seven companies extracting tin from the mine are all owned or controlled by Wa military and government leaders, Wa officials and people with close ties to UWSA leadership told Reuters.

This potentially puts companies, which also include industrial conglomerate General Electric (GE.N), at risk of violating sanctions that forbid "direct or indirect" dealings with blacklisted groups, according to a former and a serving U.S. official and lawyers with expertise in sanctions enforcement.

Several sanctions experts said the U.S. government was unlikely to fine companies who unwittingly used the Myanmar tin.