1 banana equivalent dose is approximately 15 Bq. Table 2 of this document shows the radioactivity of the coal - let's use the lowest US figures. The note above table 2 says to multiply the U-238 value by 14 and the Th-232 by 10, and add those to the K-40. The results in 124 Bq/kg for US coal, and 1628 Bq/kg for Brazilian coal. That indicates that 1 kg of unburnt US coal is 8.22 BEDs. When burnt, between 1% and 10% of the ash escapes the scrubbers and is emitted into the environment directly (new vs old plants). Assuming that all of the radioactive elements are end up in the ash/slag and NOT directly put up the flue (as would be the case with gaseous radioactive elements such as Ra-226 and Ra-228), 12.1kg of coal when burnt and passed thru 'new plant' scrubbers results in 1 BED out the smokestack. With 850 million tonnes (850x10^9 kq) burned in the US in 2009, that resulted in 70.25 billion BEDs.
If you use the worst-case US figures and an old plant, you end up with 12320 Bq/kg, which is conveniently close to 100x the best-case numbers - 0.121 kg unburnt coal = 1 BED, and 7.025 trillion BEDs up the flue. Interestingly, 121g is close to the mass of the average banana at 150g, so unburnt US 'bad' coal is as radioactive as your average banana, mass-for-mass.
In the USA, 850 million tonnes of coal was used in 2009 for electricity production. With an average content of 1.3 ppm uranium and 3.2 ppm thorium, US coal-fired electricity generation in that year gave rise to 1100 tonnes of uranium and 2700 tonnes of thorium in coal ash.
If we apply the 1% up the stack rule, that means 11 tonnes of U and 2.7 tonnes of Th went out the stack - that's a lot of radioactivity up the flue and a lot of fissionable material wasted.
It is evident that even at 1 part per million (ppm) U in coal, there is more energy in the contained uranium (if it were to be used in a fast neutron reactor) than in the coal itself. If coal had 25 ppm uranium and that uranium was used simply in a conventional reactor, it would yield half as much thermal energy as the coal.
Please check my math.