I remember the platform puzzle in the mine was redesigned a bit from D2:ED, so it was easier, but at first glance looks like it would be harder. I think I just jumped from behind the lever used to trigger the disappearing platforms, after initially trying to stand on the edge of the platform, hit the lever and jump backwards onto the first platform to theoretically save some time jumping forward to the second platform. IIRC it was easier to just face where the platforms would appear, jump forward, turn and jump again (you can pause the game as you land to rotate the camera direction, and make the second jump faster).
In another topic describing my playthrough I mentioned getting an elder class helmet out of that chest, which was a slight upgrade to the one I had been using (I cleared the mine of opponents earlier, and left the book and platform puzzles, as well as malachite veins, until I was level 35, just not getting back until I started clearing up stuff getting ready to head to the Hall of Echoes). I don't recall for sure if there were any predetermined items in the chest, but I don't think so (in any case the DKS
FAQ/Guide mentions set pieces in a couple other places in the depleted ore mine, but not this chest).
This puzzle is independent, so you can skip it and still do the one with the books and pedestals.