Sanding an End Grain Cutting board/butcher block.?

I am attempting to sand down an end grain cutting board/butcher block counter top. I need to take it down about 1/8 of an inch to level it and take out all of the imperfections. I have tried a palm sander, hand planner, and a large porter cable random orbit sander with as low as 60 grit sand paper. None of these have made the slightest dent in the hard maple end grain. Any suggestions?