This is the only known Roosevelt Dime struck on a U.S. Copper Cent alloy planchet. This unique error was authenticated by the American Numismatic Association Authentication Bureau (A.N.A.A.B.). It was a front page featured article in Numismatic News Vol. 43 No. 48 November 29.1994.
This unique discovery piece needs to be further researched for several reasons. 1964 was the last year that the United States Mint struck Silver Dimes and 1965 was the first year that Clad Dimes were struck.
This may be an experimental piece since it is a 1964 Dime struck on U.S. Copper Cent Alloy that was punched to the size of a Dime planchet. To date, this is the only known Dime struck on U.S. Copper Cent Alloy.
Below is the original auction listing by Heritage.
In 1999 they auctioned off this discovery piece.