Recently - back in May - we removed a buried fuel storage tank. We
dug out about 6' deep, maybe 8 feet wide, and 12 feet long. The hole
was refilled by the excavator, and though the excavator did a bit of
'tamping' with the bucket, not a lot of soil compaction was done.
Since then, the soil has sunk maybe 8 inches. This is in Western
Oregon; the soil is mostly clay.

We'd like to put a flagstone or paver patio over this area. What type
of soil prep is necessary? Do we need to re-excavate the entire pit,
and refill/recompact layer by layer with a jumping jack? Or can we
get away with a shallower re-excavation? Or is there some way to do
it with no excavation at all?

Is there some more expedient way to accomplish this? Just looking for
the lowest cost/effort way to prep this area for the patio, without
having to worry about re-doing it in a few years.

Thanks,

Kelly