I'm in the depleted ore mine and I've come accross a platform puzzle I can't solve.
The puzzle is where you have to jump from platform to platform and each time you'll end up a bit higher, all the way until you reach a platform with a lever. When pulling the lever, two more platforms appaer and the upper of the two has a pressure plate on it. When standing on the pressure plate, a treasure chest appears all the way at the bottom! However, when leaving the platform/preasure plate, the chest dissapears! How do I get to that chest ???

TIA!