There is a fuckton of coal in OTL Eastern Ukraine. I am sure that Russia would be willing to trade it. I don't know how useful that kind of coal is or when it was first used but it's still there and served as the backbone of Russia's (and later Ukraine's) Industry up to and including the modern day with a nickup from occupation during wwii.
Donets Basin coal is probably of sufficient quality for industrialization. As for getting it to Rhomania, could be, but transportation will be a bitch. Pre-steam engine, which will only come about from the industrial revolution, the fastest way to transport stuff from mines will be river barge. OTL Britain built a shitton of canals, but that option won't be fully available as they'd have to transship to larger vessels for the trip across the Black Sea.
You still also have the problem of what they're shipping to. If you look at the industrial clusters that popped up from the OTL industrial revolution, they were generally located close to the site of one strategic resource (e.g., coal, iron ore, wool/cotton) and had the rest shipped to them. Since Rhomania lacks both good sources of iron and coal, it just wouldn't make sense. In fact, now that I think about it, it's more likely to be a major supplier of wool to early textile industries.
Actually, come to think of it, industrialization is more likely in OTL Ukraine itself than in Rhomania, given that it has lots of rivers (Bug, Dnieper, Don, Desna, Inhulets, etc.), coal, and iron... but what it needs to industrialize the most is a large population.
