As far as I know that's pretty much exactly the amount of fissile material used annually world-wide. The caveat is of course that for 1 kg of coal you have to

As far as I know that's pretty much exactly the amount of fissile material used annually world-wide. The caveat is of course that for 1 kg of coal you have to dig up a lot less material than you have to for 1 kg of fissile material - U235 is around 1 % of natural Uranium, and Uranium is around 1 % of the ore.