It doesn't respawn. But can be brought at the magic shop in port sarim.
There are easier ways to make money than that. Do fishing.
After being mined, a mithril rock takes an average of 3 minutes to respawn.
It depends how long you are on Runescape.
It takes around 17 seconds in highly populated world.
The time for a Yew to respawn can range from 60 to 98 seconds, with the time shortening as more players are logged in to that world.
Not that long, it's almost instant.
Go to:runescpae
about 30sec or 1min
well if you played runescape 24/7 it would take probealy take 2-3 days to do .
Teremus the Devourer takes between 24h and 48h to respawn.
If you just started RuneScape maybe 30 minutes and if you already have a RuneScape account 7 minutes minimum.
depends on what your cooking