I don't know if you can make a perfect copy of the game (without haveing to apply a noCD) so i'll tell you how to make a copy that works with a noCD.

Use the program ClonyXL ( ####://clonyxl.tripod.com/ClonyXLFinal_eng.zip ) to detect the type of Protection (i think Civ3 has safedisk v2). It will also suggest settings for the program CloneCD. You can find CloneCD, the actual CD writer software, at ####://www.elby.org/.

Hope that helps