Nuclear Mines 
You can use the land mine animations with a few minor changes to make them into nuclear mines:
1.Create a subfolder under \art\units called "Nuclear Mine" (without quotes)
2.Copy all the land mine files into "Nuclear Mine" folder
3.Rename Land Mine.ini to Nuclear Mine.ini
4.Copy ICBMAttackA.flc and ICBMAttackA.wav from \art\units\ICBM to art\units\Nuclear Mine
5.Delete LandMineAttackA.flc and mineboom.wav from Nuclear Mine subfolder
6.In the Nuclear Mine subfolder, rename ICBMAttackA.flc as LandMineAttackA.flc, and rename ICBMAttackA.wav as mineboom.wav
7.Use the editor to add a "Nuclear Mine" unit to civ3mod.bic
you're done! now go get 'em