In Mac OS X 10.7 and above, The Unarchiver can extract them for use in Mini vMac or via Floppy Emu. You can download Stuffit Expander at MacFixer.
Note: These Disk Copy 4.2 disk images* are stored inside early Stuffit (.sit) archives, which can be extracted by Stuffit Expander 3.5 (and above) in System 6 (and above). The disks are complete and the files are unaltered. These are Apple's recommended releases for machines with 128K and 512K of memory.