“The Federal Reserve has so debased the value of the dollar that it is now very expensive for the U.S. Mint to buy buy and use copper, nickel and zinc in the coins it produces. Currently, a penny costs more than two cents and a nickel costs more than 11 cents to make and distribute. A 400-page report presented last week to Congress outlines nearly two years of trials conducted at the Mint in Philadelphia, where a variety of metal recipes were put through their paces in the massive facility’s high-speed coin-making machinery. But the Mint couldn’t find any good replacements. Evaluations of 29 different alloys concluded that none met the ideal list of attributes.”
http://www.economicpolicyjournal.com/2012/12/a-desperate-us-mint-testing-new-metals.html