Using
CheatEngine to enable unlimited health and armour allows entering Luculla Mines and walking through the lava to get to the section of the mine where you met Leandra, where you can take the mirror teleporter to get the spell (and other loot), then leave from the entrance hall mirror.
For CheatEngine the install you would either need to uncheck some extra 'offers', or install it while offline. There is also a
no-install rar file on the downloads page. If you don't already have an archive manager that can handle rar files, try the freeware
7-Zip.
Here is a
CheatEngine table I downloaded from
this topic (broken link) when it was still available. It wasn't updated for the latest version of the game, but works for this (I've also used it for adjusting abilities and talents).
Start the game and load a save, open the table (I just extracted it into the CheatEngine install folder), click the 'Select a process to open' button at the top left (highlighted with a flashing box cycling between red and green), select EoCApp.exe (preceded by a hex number, ie 00001FD0-EoCApp.exe) and click the Open button and then Yes. In the bottom list, select 'Unlimited Health' and 'Unlimited Durability', then enter the mine and walk through the lava.
If you can not select the boxes at the bottom in CheatEngine, exit the program and the game and start over. That happened to me a couple times. There may be an easier fix, but I haven't used CheatEngine enough to bother trying anything else.