What does it mean when an ore needs to be concentrated? Core Chemistry

I think there are two types of 'concentration' when talking about metal ores:

One is in the ore itself - if there is a high concentration of copper within a copper ore, say 20%, it's more economical to use than an ore of only 0.5%.

And you don't want to waste loads of energy extracting the metal. So when you have the rock containing the metal ore, you can concentrate it, which just means getting rid of everything in the rock that isn't the metal compound. So bauxite - a rock containing aluminium ore - is reacted with sodium hydroxide, which separates the aluminium oxide from the unwanted rock. So you end up with just the aluminium oxide, and not any of the extra stuff in the rock that you don't want. This is what they mean by concentrated.

I hope that makes sense!