[Unlicensed Dremel]

And it's even not true of aluminum. Or even oxygen, for that matter.

If we spread aluminum so thin into tens of thousands of landfills in itty bitty pieces, it's effectively non-recoverable / non-recycleable, in which case, when the mines run out, it's out.

When the earth's rotations slows down the point (and it will because it's always slowing) where the electro-magnetic field generated by this rotation combined with the nickel-iron core of the earth is significantly-reduced in power, then the solar winds (coronal mass ejections) will wipe our atmosphere clean, like the moon, and there will be no air.

There are many things which won't be around when the earth is still here in few billion more years, including homo sapiens.

Or in the case of metal minerals, they'll still be "here" somewhere, but depleted by being strewn far and wide all over the crust (in the vestigial remnants of what was our landfills and such). Won't matter a great deal, though, as it's unlikely that the living species remaining will have the intelligence to utilize them. The 2nd most advance species on earth behind humans, the bonobo, never harvests anything more sophisticated than rocks and sticks to use (for tools).