Mirroring Directory and Permissions
To do a mirror operation and properly copy the file and folder permissions, use the /sec and /secfix commands. The /sec command will copy the file security over for changed files, while the /secfix command will update the security for unchanged files.
By combining these commands with /mir you will effectively mirror all of the files, folders, and permissions from a source directory to a destination.
robocopy D:\Source\ D:\Destination /mir /sec /secfix /v /log:copy.log