Master bath remodel

I am rdemodeling my master bath. The orig. bath had a bedit next to where the new shower wall will be. I am getting rid of the bedit and want to use its water supply (h & c) as the source for my new shower.
Any problem trenching this water source to new shower then covering original hole in slab with cement? I'm using 1/2" copper.

You don't want copper embedded in ( touching ) any cement. The chemicals will cause pinhole leaks in the copper.