In mint condition

Lifting a heavy gold bar

"Diplomatic Hospitality" invites foreign diplomats or their spouses, some of them men, these days, to visit Canadian institutions in Ottawa or participate in Canadian-themed activities. Yesterday morning we took people for a tour of the Royal Canadian Mint on Sussex Drive, to learn about the coin production there.

The Ottawa mint makes commemorative coins and medals only; coinage for general distribution is minted in Winnipeg, and the Bank of Canada sees to the paper money. The Royal Mint in Ottawa,  until 1931part of the British Mint, is more than 100 years old. It has its own gold refinery.

24 carat is pure gold, whereas 10 carat gold is an alloy containing 50% silver. Ottawa made the Olympic medals for the Vancouver 2010 Olympics. The gold medal has an outer layer of 6 grams of pure gold but its inside is silver. Most commemorative coins are made of silver. It takes 300 tons of pressure to cut into a lump of silver. In the basement of the mint, the raw silver is cut into small pieces before being heated in a furnace to 1250ºC. Then it can be rolled flat into silver coils, each weighing 975 lbs. Any leftovers go back into the furnace after trimming. The coil is wound slowly between heavy rollers, then heated once again to 700º so that the strip can be rolled even thinner.

Workers wear goggles, earplugs, hairnets, lab-coats and gloves or finger protectors, depending on their assignment.  Tourists are allowed nowhere near the machinery or the coins but can see the activity through the windows of an overhead passage. At the end of each day the workers have to walk through metal detectors before leaving the premises. The Sack and Kiesselbach machines punch out blanks and leftovers are once again recycled, like pastry for mince pies. Then the rimming machine comes into action. With their rims, coins survive for up to 15 years longer than they would without.

The blank coins are spun in tumblers with small steel beads, a process that cleans and polishes their surfaces. Then they're weighed with great precision. If not perfect, they have to be re-melted, a recovery technique that saves an estimated $10,000 a week. To preserve your commemorative coins in mint condition, by the way, you should never take them out of their containers. There's a proof finish and a specimen finish and a good deal more technical vocabulary besides. I jotted down: "hobbing the working dies," "the master punch," "the matrix," "photo-etching," but don't really know what any of this means. Regarding the image on a coin, a long process creates it from a plaster positive, to a negative plaster model, to a silicon rubber positive, to a "black magic epoxy negative" (?!) to a brass model.

Some modern coins are coloured with enamel paint; this is applied by hand.

The Australian mint is Ottawa's chief rival, but a quarter of the world's population uses Canadian-minted coins. In the latest version of the Queen's profile on the reverse of Canada's coins (in use from 2003 onwards) she is not wearing a crown or tiara. As the heads of state change from one monarch to another, their heads on the coins face in different directions, except for the brothers George V and George VI who are both facing in the same direction, because George V's reign was so short.

Diplomats having fun outside the Mint

After our guided tour 26 of us walked over the road for lunch at the nearby Earl of Sussex Pub.