There is, but you'll need to make a mod that does several things...

First, you need to copy the entity manifest and remove all references to mines...

The entity manifest basically is a long list of all the entity files, and the game uses this list to load all those files at startup...I do not have all the file names memorized off the top of my head (and I'm not at home) but I'll try to do my best...don't worry about deleting the actual entity files (mods don't "delete" files, they simply add or replace), just delete the associated entries in the entity manifest...

TEC mines are a planet module, so you will need to remove that entry...Advent mines are a type of SC, so you will need to remove the squadron as well as the individual strike craft entries...Vasari have two different mines and an associated frigate, so you will need to remove all three entries...

Additionally, each mine has an associated ability, and each of these abilities has at least one buff...also, remember that the Vasari minelayer has two abilities as well (one for laying each type of mine), so there is a total of 6 ability files right there (1 for each of the 4 types of mines and 2 for the Vasari minelayer)...you will need to remove all references to these abilities and buffs...

Also, each technology related to mines (1 TEC, 1 Advent, and 2 Vasari) has an entry that needs to be removed...

It is very important that you count how many entries you remove, and change the top line of the entity manifest (which says how many entries there are) accordingly...

Second, you need to copy each player file (something like "PlayerPsi", for Advent) and remove all references to mines...

For all three factions, you will need to remove the reference to all relevant technologies (1 for TEC, 1 for Advent, and 2 for Vasari who also researches the minelayer)...remember to adjust the "number of technologies" count accordingly...then you will need to 1) for TEC, remove the tactical structure reference to mines and 2) for Vasari, remove the ship reference for the minelayer....I don't think you need to do anything in this regard for Advent...as always, adjust any "counts" accordingly...

Third, you need to copy and change the entity files for the Advent hangar and Advent Aeria Drone host...in each of these files, you will need to remove the ability of these entities to construct mine laying squadrons...

So:

• Remove all references to any structures, squadrons, or ships that are mines/mine layers; any associated abilities; any associated buffs; and any associated technologies in the entity manifest
• Remove all references to any technologies, ships, or structures that are mines/mine layers in the player files
• Remove all references to mine layer squadrons in the Advent hangar and light carrier
• REMEMBER TO CHANGE ALL "COUNTS" ACCORDINGLY in the entity manifest and player files

I apologize in advance if I forgot something or this was all confusing...

While seleuceia's way is the most complete way to do it, if it proves too much there maybe easier ways to prevent them from being built without removing them completely from the game (I.e. make the mine research cost ridiculously expensive and take a ton of labs).

Also just to be clear do not modify the base game files, copy the files Seleuceia mentions into a mod and change them there.

That doesn't mean the mod didn't work...in general you can't load a save file from a different version (though sometimes it does work)...the game mini-dumped because you started a vanilla game and then tried to reload the game while playing a mod...

Try starting a new game with your mod and see if things work out...

Ah, the .entity files would be 'integrated' (so to speak) into the saved game?

Thanks, will see what a new game does!

This makes me think you haven't even edited any entity files...you can't just remove file names from the entity manifest...you also have to remove references to those files (such as the player files or the ships/structures that have mines) so that the game doesn't look for them...

If you haven't converted any files to TXT, then you won't be able to get rid of mines regardless of which method you choose...