US Coins

Mint asks Congress to give it authority to change alloys

The U.S. Mint continues its research into developing compositional alternatives for specific circulating coin denominations that could save millions of dollars annually, while two circulating U.S. coins continue to cost more to produce and distribute than their face values.

It cost more than double face value in 2022 for the bureau to produce and distribute each Jefferson copper-nickel 5-cent coin. The cost to the Mint in 2022 to produce and distribute each copper-plated zinc cent was nearly triple its face value.

On April 18, the bureau submitted its sixth biennial report to Congress on alternative metals research as required under provisions of the Coin Modernization, Oversight, and Continuity Act of 2010, Public Law 111-302.

U.S. Mint officials recommend that Congress pass legislation granting the bureau, through the Treasury Department, the authority to implement seamless alternatives.

“There is already legislation, introduced both in the 116th and 117th Congresses, that would provide that type of authority (the Coin Metal Modification Authorization and Cost Savings Act, H.R. 1789 and S. 672),” according to the 2022 Biennial Report to Congress. “Enacting this legislation would allow the Mint to act in real time on various alternative metals.

“This would help to address market fluctuations in metals; proactively reduce risk of supply chain problems; make counterfeiting coins more difficult; and, most important, reduce costs.

“Alternatively, the Mint recommends granting authority to the Department of the Treasury to produce coins with the 80/20 alternative metal for nickels, dimes, quarters, and half-dollar denominations.

“Based on 2022 production levels, this could increase revenue by approximately $12 million per year, and it is the one alternative metal that has completed its full research. Once authorized, the Mint would need approximately one year for final supplier validation for large-scale production before starting production or general circulation in the next calendar year.

The primary recent focus of research and development testing at the Philadelphia Mint is the 5-cent denomination, currently composed of 75% copper and 25% nickel; and the copper-nickel clad dime and quarter dollar, composed of outer layers of 75% copper and 25% nickel bonded to a core of pure copper.

While earlier research also resulted in an alternative composition for the copper-plated zinc cent, the costs for any option still exceeded face value. The seamless alternative for the Lincoln cent was copper-plated steel with a weight, diameter and edge thickness similar to the current cent.

“Achieving specification coin edge thickness at reasonable stamping tonnage (40 metric tons) was the major challenge to producing a CPS penny, because of CPS planchets’ thinner gauge and higher hardness,” according to the 2022 biennial report to Congress. “The development approach was that modifying die curvature and lowering design relief would provide the best stamping results. Nonsense master tooling/stamping dies incorporating these modifications were manufactured to support further optimization stamping trials and phase two extended stamping trials.”

Researched alternatives

Testing and experimentation conducted over the past 12 years by the U.S. Mint has resulted in a number of seamless, and/or co-circulating alloy alternatives.

The denominations tested, alternatives determined, and their suitability/feasibility are:

➤ 5-cent, dime, quarter dollar, seamless, 80/20 (an alloy of 80% copper, 20% nickel).

➤ 5-cent coin, seamless, C99750T-M, a monolithic nickel alloy developed jointly with the National Institute of Standards and Technology that lessens the percentage of copper and nickel, but substitutes zinc and manganese (50.75% copper, 14% nickel, 33% zinc and 2.1% manganese). Testing included hue variants because this alloy has a tendency toward a gold hue. The hue variants were tested to better simulate the color of the copper-nickel alloy currently in use for the 5-cent denomination. This alloy offers the highest annual savings ($50.9 million) if used for the 5-cent, dime and quarter dollar denominations.

➤ Quarter dollar, co-circulate, multi-ply plated steel.

➤ Quarter dollar, co-circulate, nickel-plated steel.

➤ 5-cent coin and quarter dollar, co-circulate, nickel-plated zinc.

➤ 5-cent coin, co-circulate, R52 Stainless (monolithic).

➤ 5-cent and dime, co-circulate, nickel-plated silicon-steel.

➤ 5-cent monolithic, dime and quarter dollar, co-circulate/seamless, nickel steel (monolithic/clad).

Each of the six biennial reports to Congress can be accessed here.

Current alloys

The current alloys for the cent, 5-cent coin, dime, quarter dollar and half dollar have been used for decades or longer.

The composition of the cent was switched from an alloy of 95% copper and 5% zinc in 1982, with a 95% copper and 5% tin and zinc alloy used from 1864 to 1962. The 5-cent coin is made of same alloy introduced in 1866 when the denomination was first struck. Both compositions were briefly replaced by different ones during World War II so that the traditional metals could be used for military purposes.

The dime and quarter dollar have been made of copper-nickel clad since the 1965 issues, with the first half dollars made of that composition struck in 1971. The 90% silver, 10% copper alloy used for the three denominations through 1964 had been introduced in the 1830s. From 1965 to 1970, the half dollar was made of a silver-copper clad composition.
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