United States Mint officials are not yet ready to recommend new compositions for circulating U.S. coinage, but are continuing to study what they say is a "promising alternative."

The Mint on Dec. 12 released its 2014 Biennial Report to Congress on the research and development of alternative metals for the nation’s circulating coins, in which it reported on years of testing on various alternative compositions that could be used for U.S. coinage. The Mint has been studying alternative compositions in an effort to reduce materials costs for coinage.

According to the report: "At this juncture, there are several possible options to alter the metallic compositions that would lower the costs of United States coins, but the Mint does not recommend adopting any of these options until ongoing research is completed on a promising alternative that has the potential to duplicate the weight and EMS of existing coinage."

Among the promising alternative compositions is an alloy of 80 percent copper and 20 percent nickel. According to the Mint, it "chose the 80/20 alloy as a 'seamless' material, which matches the current material’s EMS [electromagnetic signature] and weight, and has no appreciable impact on the coin-accepting industry."

An alloy of 80 percent copper and 20 percent nickel could be used as the outer cladding on the dime, quarter dollar and half dollar, and as a solid alloy for the 5-cent coin. The Mint currently uses an alloy of 75 percent copper and 25 percent nickel for those two purposes, with the three higher denominations bearing a pure copper core.

However, the report also notes that changing to an 80 percent copper, 20 percent nickel composition would not result in substantial cost savings over the current 75 percent copper, 25 percent nickel.

In the latest round of testing, the Mint has focused on six compositions, down from 29 compositions initially tested. In addition to the 80/20 composition that has shown promise, the Mint in the most recent round of testing has studied nickel-plated steel, multi-ply-plated steel, stainless steel, copper-plated zinc, and tin-plated copper-plated zinc.

Additional findings

The report offers various interesting points, including a study of the possible use of a ringed-bimetallic composition, which the Mint said would be cost-efective only on higher denomination coins of $1 or more; consultation with the Royal Mint and Royal Canadian Mint, which assisted the U.S. Mint on the production of "nonsense dies" used in striking experimental coins; and industry reactions to possible compositional changes.

Coin World will report in greater detail on the 2014 research and development report in the days ahead.

The report can be found here.

This report is the second released under the Coin Modernization, Oversight, and Continuity Act of 2010.

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