Oh, surely it is possible, but how? The original AI has this and many more aspects. The AI complexity is its problem or, rather, my problem. I tried to stress resource boni more but it somehow did not work. It does not work properly in the original game, so who should be surprised by it... Many times, you pull some lever up imagining what it might lead to, but instead you get some other response, because some other emergency hidden mechanism (you obviously had no idea about) kicks in. Wish I knew how this can be done.
I'm not certain about this, might it be possible that the AI is so eager to plant mines all over the place because you also explicitly told it to build roads there? You could try encouraging it to place roads on resource specials, and see what happens.
If watched a few more games since I wrote the first post, here's what I've noticed:
1) Mines are definitely a problem as is. The AI builds lots of them, but they rarely ever get worked. This amounts to a lot of wasted former time.
I'm inclined to recommend you change it that the AI either leaves ordinary rocky squares unworked, or that it uses 'terraform level' on them and builds other improvements. If a rocky square is on level terrain, it would also a good spot for a borehole later on.
The exception are mineral specials - a mineral mine will produce 0/7/0, that's big enough to convince the AI to work them. There is one borderline case where it might make sense (for the AI) to build a mine in rolling terrain; if it is rainy and has a mineral special, a farm + mine + road will boost it to 2/5/0. However, a forest or depending on elevation, a farm + solar would get you nearly as much, for less terraforming investment. I thought I'd mention it because the AI can tend to get a little mineral-starved with its focus on farm + solar.
For nutrient and energy specials, or minerals on flat terrain, it's better to build something else. for nutrients, leveling the terrain is best. It might be possible to leave a rocky/energy square for a borehole, if it's on level terrain.
2) The AI does build condensers. However, with your rules for farms + solars, it won't build them on farms anymore. This is a problem. Absent pop-booming, condenser farms are probably the best way to boost the AI's growth and mid-game power.
3a) It's rarely used by human players, but remember that 'logging' a forest by building something else there will add 5 minerals to the nearest base. For some squares, it might be worthwhile to simply have the AI plant forests at first, and then construct other improvements as the restrictions get lifted and/or advanced terraforming becomes available.
3b) Forests are great on rivers. Before restrictions are lifted, you can't beat getting 1/2/2 for only 4 turns of terraforming. They also seem to spread fast along rivers.
3c) I believe the original AI would increase planting forests once it had tree farms/hybrid forests. In tends to happen quite late for the AI, but even so, you should add a check that once a base has a TF, forests take precedent over farm/solar at <2k elevation.
4) On reconsideration, I think farm/solars aren't bad at 2k+ elevation. If you can get the AI to intersperse them with an occasional Echelon Mirror, they should become quite solid.
I am grateful for your concrete suggestions, very good. You may think about more and putting here, aquifers at 2k+, should work perfectly and is generally easy to do. My problem with advanced terraforming is that the function is very complex and embroiled in some sets of rules which I do not understand one little bit. I believe this has a lot to do with scenario settings and multiplayer. I did not play them, I am unfamiliar with the special rules and I am lost in their quantity. Hell, if original Alpha Centauri weren't multiplayer, I'd have a lot more progress on AI front. It makes the code understanding foolish.
In general, I would love to see here a set of rules for advanced terraforming similar to the table I put above. Can you make it? That would help me.
Can you go into a little more detail what conditions you can easily check for? Buildings present in the city, i.e. tree farms? Eco-damage? Can you make a check what terraformings/conditions are present in adjacent tiles? IIRC, the AI can 'cheat' in the base game by building boreholes next to each other. It would be good to fix that, and this would probably also be necessary so it can't drill aquifiers next to existing rivers.
Example:
Improvement: Borehole
conditions
a) necessary: City has at least 6 size
b) City has at least +2 nutrients output
c) flat terrain unworked tile present
d) City has no other borehole
etc...
then odds are XYZ to start a borehole.
I can try my hand on condensers for a start. I think those are more important, as they can be available quite early, if the AI gets the Weather Paradigm. (Boreholes are pointless until the restrictions get lifted, even if you could build them earlier.) The big question is how well the AI can handle the eco-damage from advanced terraforming.
Improvement: Condenser
First of all the basic squares
moist/rainy + rolling + 0k
moist/rainy + rolling + nuts
Making rolling a requirement should keep the AI from simply plastering condensers everywhere at ground level. The condenser should bring a moist square up to rainy, so there's no difference between the two. Before soil enrichers, these will provide 4 or 7 nuts each. These are the kinds of squares the AI shouldn't build solars on to leave room for condensers.
Conditions:
a) Eco-damage is 0
b) Base isn't at population limit, if it has a Hab Complex
c) farm built on square
d) limit 2/3 condensers if there's no Hab Complex in base (Morgan/rest). - (This assumes that bases' radius overlaps, i.e. condensers can be in the radius, but worked by another city.)
e) limit 4/6 if there's a Hab Complex. (Morgan/rest) (By the time you get Domes, you shouldn't depend on condensers alone anymore.)
That's my first shot. It's probably a good idea if we take this discussion to the various Alpha Centauri forums, so that anyone who still plays the game a lot can contribute.