They could make a zero emmission coal powerplant if they were willing to invest the money and if regulation required it. You would basically have a building aboutt he size of your generaor dedicated to air scrubbing. Think Catylitic converters, but on a massive scale, probably followed by electrostatic seperation for the rest of the particulate matter, and then pump the remaining exhaust gasses through an algae farm, then use the algae for biomass for biofuels.
A nuclear power plant would be far cheaper, and far less polluting. The current generation pebble bed reactors literally cannot go critical even if they lose coolant and are running at full capacity. The waste material is a problem, but it is less of a problem than coal residue, and I would bet money we are less than a generation away from a working Fusion reactor, in which case, problem solved, you feed the fission waste into the fusion reactor and let it take care of the waste for us.
The coal companies really have it coming though. They treat their workers like ****, they don't make a good faith effort to restore the land in most cases, and have been tring to ***** us all over for years is finally starting to catch up to them.