I was watching some primitive technology channels. They show that a bucket of metal ore can make a spoonful or three of raw metal ingots. But most prospectors nowadays use water staircases to density-concentrate ore before smelting.
Is this a relatively new invention? Or did primitive peoples concentrate ore before refining too?
Thank you.
For mined ores and ores collected in pieces on the surface, chunks of ore are usually just picked by hand. This can give a reasonably pure ore (more than 50% ore, less than 50% other rock). With a copper ore (about 50% ore, 50% other rock), a yield of about 20% copper can be obtained (see W. Rostoker, "Some Experiments in Prehistoric Copper Smelting", Paléorient 3, 311-315 (1975), DOI : https://doi.org/10.3406/paleo.1975.4209 for an example).
If the ore is collected from the surface, the collection process is essentially just hand-picking the ore. If the ore is mined (ancient-style), it's mined by hand, with hand-tools (with fire used for rock-breaking), and hand-picking the ore doesn't add significantly to the already considerable labour in mining the ore.
Panning was certainly used, notably for concentrating iron sand. Without panning or some other washing process, many iron sand deposits are only a few percent ore, but with panning or sluicing, the ore can be concentrated to 50%.