The bullion story
Refining gold at Giant Mine just part of the process
by Nancy Gardiner
NNSL (Oct 29/97) - When you visit the depths of a gold mine, all you see is rock and muck. When you walk into a refinery like Royal Oak's, you see almost pure gold.
The bullion bars poured at Royal Oak's Giant Mine are 80 per cent gold, 15 per cent silver and the remainder other metals. They are about the size of a loaf of bread.
Should you be fortunate to pick up one of the bars (for fun), it weighs about 62.5 pounds -- about 725 troy ounces. A single bar poured last week is worth about $300,000, possibly a little less.
The bars are sent to a smelter in the South, where gold, silver, copper are separated, then are poured into pure gold bars.
Each mine's bars are slightly different in content. "What's at Giant is slightly different than Con," says refiner Ralph Creed, clad in a silver fireproof suit that covers him from head to toe, making him look like a moon-walker.
Creed is originally from Kenora, Ont., but has been a full-time refiner for about a year. His refinery helper, Dave McWhinnie, is from Timmins, Ont. The two work as an in-synch team at gold-pouring time.
"I assist in mixing up precipitate, help pouring slag and brick gold bars," says McWhinnie. The precipitate comes from the processing plant.
The fuel-oil furnace sounds like it's fired up by a jet engine. The intense heat melts the precipitate. A blasting flame escapes from a large hole in the barrel-like furnace. Two furnaces are used and one is on standby.
A precipitate mixture is poured into the 2,000-degree Fahrenheit furnace in 100-pound bucket batches. It contains a flux of four agents: sodium nitrate, borax, soda ash and silicate.
It takes about three hours for the precipitate mixture in the furnace to melt down, ready for the gold pouring.
The slag waste of zinc dust and flux is poured off first, hardening into substance almost like glass.
Then the furnace rolls again like a drum on its side, this time dispensing searing liquid gold into a bar mould below.
"The gold is hard almost immediately, as soon as it's poured. That's why it's such a good conductor, it transfers the heat out of itself almost immediately," says refiner Ralph Creed.
"That's what makes gold so valuable for the electronics industry." For example, you get better sound quality with gold-coated (electronic) jacks, adds McWhinnie.
It takes about a few minutes for the gold brick to cool. In contrast, the slag takes a couple of hours to cool.