As long as they are just the small feeder roots, yes. But they will grow back and depending on the type of maple involved, make the area under the tree canopy so inhospitable most plants will not grow well.

Part of the issue is raising the soil level surrounding the tree. This effectively smothers the fine feeder roots located just below the soil surface and why the tree is now sending roots up into the added enriched soil.....it's trying to breath :-) If the area of raised soil is extensive enough, it can eventually kill the tree.

Larger maples are notoriously difficult to garden under due to this sort of root competition, the dryness it creates, lack of nutrients and the amount of shade. There are some plants that will work but it is a pretty short list.

thanks this is exactly what i needed to know.

Based on my understanding of what you say... at this point my best bet, in terms of the tree's health, is to just leave the raised border alone... don't try to plant anything... lightly mulch.