I visited a copper mine in Arizona! Absolutely fascinating. I'm remembering bubbles on a flowing metallic surface, but no idea what the memory is about.
Grandfather was
Jack Bell. He had a
copper-gold claim that started the Buckskin stampede. Won and lost fortunes from Alaska down to Central America. Stetson and six shooter, with a
gunfight at the bottom of a silver mine.
The process you recall was “floatation”. In the mill/concentrated they first crush and use a ball mill to grind the ore finely. They then use reagents and frothing agents to separate the ore particles from the waste (tails). The ore is concentrated to about 25% copper and heavy metals which is then smelted and the metals are separated from the slag (waste).