Due diligence seems to involve surveying direct suppliers and participation in CFSI.

"Our due diligence measures included conducting a supply-chain survey with Tier 1 production suppliers using the CMRT, which contains questions about the facilities used to process these minerals, as well as supplier due diligence. The goal of this activity was to identify, where applicable, the 3TG smelters or refiners who contribute refined conflict minerals to Xerox components, assemblies and Original Equipment Manufacturer (OEM) Products. The CMRT was developed to facilitate disclosure and communication of information regarding smelters or refiners that provide material to a company’s supply chain. It includes questions regarding a company’s conflict-free policy, engagement with its direct suppliers, and a listing of the smelters or refiners the company and its suppliers use. In addition, our current standard supplier contracts also require our suppliers to adopt a policy on the responsible sourcing of minerals, implement due diligence processes to support that policy, and complete and return to Xerox the CFSI CMRT.

Our Tier 1 supplier survey request also included the CFSI informational links on available conflict mineral and smelter information."