We use rebar for staking our pavillions down when we go camping...
the trick to pulling them out is to first tap them tangengential to
the hole.... This makes the hole just a bit wider, which allows for
some room to stop it gripping. Then you pull directly inline with the
hole. Any "sideways" pulling will make it very difficult.
We usually leave the rope on the stake to make it easier.

We pull 1" rebar pounded 3' (we call them "pennsic penetrators",
after the name of the camping event) in the ground out by hand
this way. Of course, the ground there is heavy clay, so your shale might
make a difference.

Have you considered that there might be a concrete plug at the base of
the rebar? good luck in any case!

--
May no harm befall you,
flip
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