March 2000

All That Glitters is Mostly Copper - Part 1

Copper Applications in General Interest

By Konard J. A. Kundig, Ph.D.

All That Glitters is Mostly Copper - Part 2

Congress Defines New Coin's Attributes

The Sacagawea Dollar New U.S. "Golden Dollar," Made from New Bronze Alloy:
Incorporates Innovative Metallurgical Technology

By law, issuance of any new coinage by the U.S. government requires an act of Congress. The enabling legislation in this case was The United States One Dollar Coin Act of 1997. The Act is an interesting document, actually somewhat unique as these things go, because it not only mandated that a new dollar should be minted, it was quite specific about the coin's size and appearance, and even its physical properties. For example:

  • The new coin would be golden in color, thus making it readily distinguishable from the Susan B. Anthony (SBA) dollar, whose acceptance by the public was limited as a result of its similarity to the quarter.
  • The coin would be the same diameter (26.5 millimeters, 1.043 in) and weight (8.1 grams, 0.286 ounces) as the SBA, thereby avoiding the need to modify the literally millions of existing coin-acceptance machines found in toll booths, token dispensers, vending machines, car washes and coin-operated laundries, to name just a few examples. This was very important because the cost of modification would have been extremely high, and it would ultimately have been borne by the public.
  • The coin would be smooth-edged, like the nickel. In the language of the Act, the coin's edge must incorporate "tactile and visual features...that make the coin discernible, and distinctive so as not to be confused with the quarter—which has reeds (grooves) all the way around its edge—and is easy to find among other coins." Those features make the coin identifiable to folks who can't see well, or for that matter, anyone who has ever fumbled for correct change in the dark.

Now comes the interesting part...

  • The new dollar must, by law, have metallic, anti-counterfeiting properties similar to currently circulating U.S. coins. That's where copper becomes virtually irreplaceable.

Most Coins are Mostly Copper

Since the switch from silver more than 30 years ago, most U.S. coins have largely been made from copper. Look at the edge of any dime, quarter, 50-cent piece or SBA and three metallic layers are easily discernable. The outer two layers are made from alloys of copper and nickel, 87.5% copper—12.5% nickel in the case of the SBA and 75% copper—25% nickel in the others. (The nickel 5-cent coin is entirely 75-25 copper-nickel.) The inner layer, which comprises 50% of the thickness in both the SBA and the Golden Dollar (33% in other coins), is pure copper. Thus, there is an aggregate of 88.5% copper in the new dollar, up from an aggregate 87.5% in the SBA.

How much copper will be needed to make the new dollars is difficult to say because the Mint doesn't yet know how many of the new coins will be needed. The two key questions are:

  • Will the public accept the coin, and even more important,
  • Will the Golden Dollar eventually replace the paper greenback entirely?

It already appears that the new dollar will be considerably more popular than the SBA, having overcome many of the older coin's unfavorable features. In fact, market research conducted by the Mint indicates that consumers are ready to incorporate the Golden Dollar into their everyday lives. Studies showed that 65% of U.S. adults expect to spend and receive the new dollar coin in routine retail transactions; 55% expect to be able to obtain the new dollar coin from their local banks, and 30% said that they actually prefer to receive the dollar coin as change over the dollar bill.

Whether the Golden Dollar totally replaces paper currency depends on the government's willingness to take such a revolutionary step. According to James Benfield, director of the Coinage Coalition (a Washington-based organization that serves manufacturers and users of coin-acceptance equipment and related industries), experience in other countries has shown that the substitution of coinage for paper money is usually followed by a temporary period of public outcry. "The complaints are always similar," says Benfield. "People complain that the coins will be too heavy to carry, they regret having to give up a familiar banknote and believe (incorrectly) that the coins are worth less than the bills they replaced, among other things. After about six months, however, the complaints subside as people get used to the new coinage and begin to appreciate its advantages. Canada provides an excellent example. Canadians soon became so comfortable with their one-dollar 'loonie' that their Mint subsequently produced an equally successful two-dollar 'twonie'".

Time will tell whether the Golden Dollar becomes broadly accepted. If it is, the outcome will have a measurable effect on the amount of copper needed. That is not to say that even a huge demand for the new coins would create a shortage of copper or anything near it. Coinage of all denominations accounts for a only small fraction of the total amount of copper used in this and other countries.

The Mint initially envisioned a demand for between 50 and 100 million new dollar coins in 2000. Estimates have been revised upwards several times as public interest in the coin has grown, and actual demand may rise to the 1.0-1.5 billion coin level this year.

Since the new dollar weighs 8.1 grams (precisely the same as the SBA) and contains 7.17 grams of copper, each 100 million coins will require 1,580,000 pounds of the red metal. Almost 24 million pounds of copper would be needed if demand reaches 1.5 billion coins. To put that figure in perspective, the U.S. consumed 6,342,000,000 pounds of refined (i.e., newly mined) copper in 1998—the most recent year for which comprehensive data are currently available—and that figure doesn't include the vast amount of copper that is routinely recycled. Thus, the new coin may take up only about 0.4% of our annual refined copper consumption.

Speaking of recycling, it is interesting to note that the webbing left over when coins are punched from strip is 100% recycled to make—what else?—more coins. All that is necessary is the addition of alloying elements to adjust the composition of the scrap (which contains both the outer (alloy) and inner (copper) layers of the coin's sandwich construction) to that of the original cladding. This process may seem only sensible, but it points out copper's high degree of recyclability—100% in this case.

If the Golden Dollar actually replaces the dollar bill in general circulation, copper consumption numbers will go much higher for awhile, but the impact will only be temporary since coins tend to remain in circulation for approximately 25 years. Even in ordinary coinage, copper and its alloys are superbly durable.

In terms of copper usage, the really substantial numbers come as a result of the Mint's incredibly successful State Quarters program. Historically, the Mint produced around 1.5 to 2.0 billion of the "conventional" Washington quarters annually. This year (2000), production may increase to some 7 billion of the 25-cent pieces featuring the individual states. The quarters' faces are made from a 75% copper—25% nickel alloy; the interior of the sandwich is pure copper. The surface layers in this case comprise one-third of the coin's thickness, giving the quarter an aggregate copper content of 91.67%. A quarter weighs 5.67 grams (containing a little less than 5.2 grams of copper) so seven billion of the coins require about 40,000 tons of copper. That's about 20% lower than the amount of copper we once used for pennies.

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