Until someone creates a machine that can pulverise anything into a fine powder and progressively sort each granule into their constituent metal, plastic, silica and organic type.

You use that machine on better ore.

That doesn’t make chemical sense. There is a huge energetic cost to smelting ore to remove the oxides, vs. landfill material that is exactly what you need but just needs to be sorted and cleaned.

The concentrations of valuable materials in the landfill are minuscule. It doesn't make energy sense to sort it even though the fractions are relatively ready to use.

Use it on landfill and you get to mine many desirable materials in one place.

Or recyclables.

There are places that run their entire waste stream through a recovery plant:

http://waste-technology.co.uk/what-is-a-dirty-mrf-and-why-th...

A substantial portion of the waste stream is just organic material (which is worth very little).

On a literal sense no less