We already mine landfills -- mostly for land reclamation but sometimes to recover resources.

In the longer run, when there's been more compaction, settling, and densification (and changes in what things are valuable), and more need to reclaim land that was previously landfilled, we will do this more.

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PaulHoule 4 hours ago | parent [-]

People sometimes build stuff on top of landfills.

	▲	dekhn 21 minutes ago \| parent \| next [-]
		Example: Shoreline Amphitheater, near Google HQ in Mountain View. Built on top of a landfill. For a while in the 80s, there were occasionally small fires during shows when people lit cigarettes. Google also harvested the methane and used it to power some stuff, although I can't find an authoritative article with details.
	▲	rootusrootus 2 hours ago \| parent \| prev \| next [-]
		Indeed, sometimes big things. The landfill we used when I was growing up is now beneath a Home Depot, which was built over the top of it almost 25 years ago. The landfill in this case was unlined, too.
	▲	mlyle 2 hours ago \| parent \| prev \| next [-]
		Yup. It is a little undesirable for various reasons, and not every landfill is suitable for construction on top (seismics, sealing/capping technique, materials, etc).
	▲	salad-tycoon 3 hours ago \| parent \| prev [-]
		Like ski courses!