No conflicts here*

In the company's 2014 Supplier Responsibility report published on Wednesday, Apple identified that its suppliers use 20 global smelters or refiners whose tantalum has been verified by third-party auditors as what the industry calls “conflict-free.”…

For gold, tin, and tungsten, Apple has had less success because it does not have as much financial leverage to pressure the smelters. It identified 166 smelters of the other three minerals used by its suppliers. The majority of those firms have not agreed to an audit…

The Wall Street Journal

In case you were wondering: Tantalum.