I'm done. Finally! After finding how I got stuck on the second chest, I finished the entire rest of the game in less than two hours. Craziness!
Travelling to the Mines
(5– The meadows )
The entrance back into the cave is at the top let side of the meadows. To reach this point climb on top of the pillars of rock that are over the river, then leap off the left side and onto the higher platform.
Proceed into the cave.
I've replied in more detail to your thread about this, but I think you just need to start with a running jump.