First shot - its not oli in tower - it coal and coal dust~smoke :) . This smoke is done in after effects so its chance i can fix it quickly.
Smoke from chimney towers. Its much more complicated than i expect.. im not fx specialist.. and i have to say its very difficult for me to make it right . First i had big problems with right speed of it. When i was play with timescale , speed was better but then i started to loose detials ( it was looking like blured). There is wind , thats why this smoke is going a bit to side. But when i did stronger wind then smoke behaved exacly the same but faster, and again when i was trying to slow it down by time scale it was loosing details... I was trying to add few winds with turbulences ect.. nothing helped.. when some part was looking better then other behaved very bad .. and vice versa with other settings.. And every test with even medium detail took a lot of time.. Maybe if some time will left i will try do another somulation for only upper part of this smoke and will try blend it with what i have now.
Shape i will leave as it is, true its wierd but i like it I had hidden plan - ok i will tell you , i was thinking about last shot where flesh creature will stand up from underground to out side of mine and this creature will be very similar shape - that way all will connect as a puzzel :). Similar shot to opent shot but everything is destroyed and huge moster in exchange of somke from chimneys.
third shot - exacly , there missing some cool fx. I was thinking about volume fog and maybe some water dropes from pipes :). I will try your idea with 'jet steam' - it should give cool atmosphere :)