By Dan McGraw
April 10 marks the first anniversary of the landslide in the Bingham Canyon copper mine, the largest spontaneous landslide on the continent and the first known to have created mini-earthquakes.
Accelerating micro-motions detected in advance allowed evacuation so no one was killed, injured, or even frightened during the slide, although there were many struck dumb. Perhaps it’s time to break the silence and ask what did it all mean? Or more broadly, what does copper mean? Since copper too seems mute on the subject, we will have to take a more oblique approach and let actions speak.
We are 1 millionth part copper. The ground underfoot is a hundred times richer, but apparently to no avail; copper plays a critical role in our life but not so much in the dirt’s. A lone copper atom enables an enzyme to make our connective tissue. It holds us together and makes us flexible and tough. Without it, horses heads would droop and we’d tear like cellophane.
Copper is also found conducting traffic at a critical junction in photosynthesis; directing energy from light to grow the plant out of thin air, excreting oxygen in the process. But this oxygen couldn’t give us the gumption to get up off the floor but for iron to carry it from our lungs to our cells, which in turn wouldn’t happen without copper to chaperone iron through our intestine wall, from gut to bloodstream.
Our copper deposits are essentially volcanoes that didn’t blow. As the magma pushed toward the surface, it progressively concentrated copper in such a way that the richest eighth of any tonnage contains about a quarter the copper, typically peppered in flecks throughout the rock. In contrast to copper’s wide dissemination, silver is more clustered, running in veins with the richest eighth tonnage holding most of the precious metal.
Interestingly, the distribution of wealth in our society can be similarly described: Today we are trending toward a top-heavy silver-like society where the richest eighth holds most of the wealth. This trend probably can’t be blamed on copper, though. Industrialization and electrification left us in mid-century with a society much like our copper deposits - holding most of its wealth in the poorest two-thirds.
The generosity that enabled this orange metal to catalyze industrialization can be quantified. Hooking up identical copper and teflon wires to your car battery reveals copper to be very forthcoming; giving 1 billion-trillion-billion electrons before teflon coughs up a single one. That’s a big number: 1 with thirty zeros. That many copper atoms (a morning’s production from Bingham Canyon) would make a wire the width of your finger stretch around the earth. And unlike our society our copper reserve’s continue to hold most of their wealth in the lower grades, as yet un-mined.
Those flecks of copper in Bingham Canyon cannot be detected with a metal detector but can be with a radio. You can conduct a copper choir in rock by blasting a high power radio tuned to 18.5 MHz on your AM dial. An antenna detects a clear echo originating from these tiny copper tabernacles in stone.
The song is evidently from the heart; it originates from the copper nucleus and is greatly amplified and raised three octaves by the magnetism of iron alloyed in these flecks of the mineral chalcopyrite — home to most of the world’s remaining copper. Without our orchestration it sings still, mainly to the choir but always in perfect tune and forever, as if to say, "We’re here! We’re here!"
Dan McGraw is a physicist and visiting associate professor of mining engineering at the University of Utah.
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