Nearly 80 per cent of U.S. public companies analyzed by human rights groups are failing to adequately check and disclose whether their products contain conflict minerals from Central Africa, a new report by Amnesty International and Global Witness reveals...The report, Digging for Transparency, analyzes 100 conflict minerals reports filed by companies...under the 2010 Dodd Frank Act..., known as the conflict minerals law. The findings point to alarming gaps in U.S. corporate transparency...The Democratic Republic of Congo...is an important source of minerals...For over fifteen years armed groups in eastern DRC have preyed on the mining sector to finance their operations with devastating impact, committing gross human rights abuses in the process...79 of the 100 companies analyzed failed to meet the minimum requirements of the U.S. conflict minerals law...[O]ne in five surveyed companies did comply with the law's requirements. This dismantles the argument...that implementation is too difficult and too expensive...