Taking 1 ton of Coal as 2000 lbs. MW of Carbon as 12, Oxygen as 16, and CO2 as 44.
The Carbon in coal varies widely from 46% to 98%. It will also contain organic Sulfur compounds, Oxygen, Hydrogen Sulfide, and ammonia. The composition will depend on the mines it was taken from. The more Carbon it contains, the more heat it will release when burned. It's the same with crude oil. Different fields produce crude with different compositions. The better quality it is, the more expensive it is.
Now, a basic combustion reaction is:
C + O2 to CO2 + H2O (imagine the numbers as subscripts, and yes, that equation isn't balanced) An incomplete combustion will yield CO instead of CO2.
But, assuming the coal is 98% Carbon, that's 2000lbs of coal. That's 1960 lbs of Carbon or 163 lb-mols of Carbon. So it's 1 mols C to 1 mols CO2. That's now 163 lb-mols of CO2 or 7186 lbs of CO2.
At the lower end of 46%, that's 880 lbs of Carbon or 73.3 lb-mols of Carbon. That's 73.3 lb-mols of CO2 produced or 3401 lbs of CO2.
So, 7186 lbs to 3401 lbs.